- Email: [email protected]
Impact of Dialysis on 30-Day Outcomes After Spinal Fusion Surgery for Pathologic Fractures: Insights from a National Quality Registry
Original Article
Impact of Dialysis on 30-Day Outcomes After Spinal Fusion Surgery for Pathologic Fractures: Insights from a National Quality Registry Mohammed Ali Alvi1,2, Jad Zreik1,2, Waseem Wahood1,2, Anshit Goyal1,2, Brett A. Freedman3, Arjun S. Sebastian3, Mohamad Bydon1,2
BACKGROUND: Patients with chronic renal failure undergoing hemodialysis have been shown to have poor overall health, osteoporosis, and altered bone metabolism. However, the impact of hemodialysis on patient outcomes after spinal fusion remains unknown. We sought to assess the effect of dialysis on 30-day perioperative and postoperative outcomes after cervical and lumbar fusion for pathologic compression fractures.
-
METHODS: We queried the National Surgical Quality Improvement Program from 2009 to 2016 for patients undergoing cervical or lumbar fusion for compression fractures. Three-to-one propensity score matching using sex, age, body mass index, and number of operated levels was used to match patients not undergoing dialysis with those undergoing dialysis. Multivariable conditional regression was used to identify the association between dialysis and 30-day clinical outcomes, after adjusting for confounders.
-
RESULTS: A total of 48,492 patients undergoing cervical fusion were identified; 156 (0.32%) of these were on dialysis. On multivariable regression, dialysis dependency was associated with increased operative time (regression coefficient [coef.], 15.93; 95% CI, 0.4e31.5; P [ 0.045), length of stay (coef. 6.06; 95% CI, 4.64e7.48; P < 0.001), 30-day readmissions (odds ratio [OR], 1.07; 95% CI, 1.02e1.12;
-
Key words Cervical - Dialysis - Fusion - Lumbar - NSQIP - Spine - Surgery -
Abbreviations and Acronyms ACS-NSQIP: American College of Surgeons National Surgical Quality Improvement Program ASA: American Association of Anesthesiologists BMI: Body mass index Coef.: Regression coefficient CPT: Current Procedural Terminology CRF: Chronic renal failure ICD-9-CM: International Classification of Diseases, Ninth Revision, Clinical Modification
WORLD NEUROSURGERY -: e1-e12, - 2019
P [ 0.009), any complications (OR 1.08; 95% CI, 1.03e1.13; P [ 0.002), and serious complications (OR, 1.08; 95% CI, 1.02e1.14; P [ 0.012). A total of 25,417 patients undergoing lumbar fusion were identified; 51 of these (0.2%) were on dialysis. On multivariable regression, dialysis dependency was associated with significantly higher length of stay (coef. 2.98; 95% CI, 1.28e4.68; P < 0.001). CONCLUSIONS: Our analyses indicated that dialysis dependency is associated with poor perioperative and postoperative outcomes after cervical/lumbar fusion for pathologic compression fractures.
-
INTRODUCTION
C
hronic renal failure (CRF) is a major public health issue with increasing prevalence and debilitating associated morbidity.1 In the United States in 2015, >660,000 Americans were being treated for CRF, with 468,000 of those on dialysis.2 Patients with CRF often experience disturbances in mineral and bone metabolism, which can lead to altered bone microstructure and strength.1,3-5 As a result, these patients more often have poorer overall health, osteoporosis, and increased risk for bone fracture, including vertebral fractures.4-6 CRF may
ICD-10-CM: International Classification of Diseases, Tenth Revision, Clinical Modification OR: Odds ratio ROR: Return to operation room SSI: Surgical site infection From the 1Mayo Clinic Neuro-Informatics Laboratory and Departments of 2Neurologic Surgery and 3Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota, USA To whom correspondence should be addressed: Mohamad Bydon, M.D. [E-mail: [email protected]] Mohammed Ali Alvi and Jad Zreik contributed equally to the article. Citation: World Neurosurg. (2019). https://doi.org/10.1016/j.wneu.2019.07.021 Journal homepage: www.journals.elsevier.com/world-neurosurgery Available online: www.sciencedirect.com 1878-8750/$ - see front matter ª 2019 Elsevier Inc. All rights reserved.
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Unmatched No Dialysis (n [ 48336)
Dialysis (n [ 156)
Age (years), median (Q1eQ3)
54 (46e63)
Male sex, n (%)
23,962 (49.6)
Matched Total (n [ 48492)
P Value
No Dialysis (n [ 467)
Dialysis (n [ 155)
Total (n [ 622)
P Value
60 (55e66.25)
54 (46e63)
<0.001
60 (54e65)
60 (55e66.5)
60 (54e66)
0.376
101 (64.7)
24,063 (49.6)
<0.001
293 (62.7)
100 (64.5)
393 (63.2)
0.699
Demographics
<0.001
Race, n (%)
MOHAMMED ALI ALVI ET AL.
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Table 1. Demographic, Preoperative, and Operative Variables for Unmatched and Matched Patients Undergoing Cervical Fusion
<0.001
White
8521 (79.7)
62 (39.7)
38,583 (79.6)
361 (77.3)
62 (40.0)
423 (68)
Black or African American
5045 (10.4)
77 (49.4)
5122 (10.6)
51 (10.9)
76 (49.0)
127 (20.4)
Other
1354 (2.8)
8 (5.1)
1362 (2.8)
12 (3.6)
8 (5.2)
20 (3.2)
Unknown
3416 (7.1)
9 (5.8)
3425 (7.1)
43 (9.2)
9 (5.8)
52 (8.4)
29.3 (25.7e33.8)
27.8 (24.0e33.0)
29.3 (25.7e33.8)
27.9 (24.6e31.7)
27.8 (24.0e33.0)
27.9 (24.5e31.8)
Comorbidities
Independent
0.003 <0.001
Functional status, n (%)
<0.001
0.802 <0.001
47,093 (97.4)
121 (77.6)
47,214 (97.4)
456 (97.6)
120 (77.4)
576 (92.6)
Partially dependent
865 (1.8)
33 (21.2)
898 (1.9)
9 (1.9)
22 (21.3)
42 (6.8)
Totally dependent
95 (0.2)
1 (0.6)
96 (0.2)
0 (0.0)
1 (0.6)
1 (0.2)
283 (0.6)
1 (0.6)
284 (0.6)
2 (0.4)
1 (0.6)
3 (0.5)
13,670 (28.3)
45 (28.8)
13,715 (28.3)
0.88
145 (31.0)
45 (29.0)
190 (30.5)
0.637
Diabetes, n (%)
7648 (15.8)
57 (36.5)
7705 (15.9)
<0.001
77 (16.5)
56 (36.1)
133 (21.4)
<0.001
Steroid use, n (%)
1650 (3.4)
8 (5.1)
1658 (3.4)
0.239
20 (4.3)
8 (5.2)
28 (4.5)
0.648
Weight loss, n (%)
110 (0.2)
4 (2.6)
114 (0.2)
<0.001
2 (0.4)
4 (2.6)
6 (1.0)
0.018
Dyspnea, n (%)
2546 (5.3)
23 (14.7)
2569 (5.3)
<0.001
32 (6.9)
23 (14.8)
55 (8.8)
0.006
Bleeding disorder, n (%)
586 (1.2)
18 (11.5)
604 (1.2)
<0.001
2 (0.4)
18 (11.6)
20 (3.2)
<0.001
Open wound/wound infection, n (%)
196 (0.4)
4 (2.6)
200 (0.4)
<0.001
3 (0.6)
4 (2.6)
7 (1.1)
0.047
Preoperative blood transfusion, n (%)
44 (0.1)
6 (3.8)
50 (0.1)
<0.001
1 (0.2)
6 (3.9)
7 (1.1)
<0.001
1859 (3.8)
0 (0.0)
1859 (3.8)
11 (2.4)
0 (0.0)
11 (1.8)
2 (mild disturbance)
25,720 (53.2)
6 (3.8)
25,726 (53.1)
234 (50.1)
6 (3.0)
240 (38.6)
3 (severe disturbance)
19,663 (40.7)
76 (48.7)
19,739 (40.7)
204 (43.7)
76 (49.0)
280 (45.0)
Operative <0.001
American Association of Anesthesiologists class, n (%) 1 (no disturbance)
<0.001
ORIGINAL ARTICLE
Unknown Smoke, n (%)
IMPACT OF DIALYSIS ON 30-DAY OUTCOMES AFTER SPINAL FUSION
WORLD NEUROSURGERY, https://doi.org/10.1016/j.wneu.2019.07.021
Body mass index, median (Q1eQ3)
ORIGINAL ARTICLE
167 (26.8)
25 (4.0)
4 (0.6)
575 (92.4)
44 (7.1)
36 (23.2)
8 (5.2)
1 (0.6)
134 (86.5)
19 (12.3)
37 (23.7)
8 (5.1)
1 (0.6)
14,568 (30.1)
2063 (4.3)
412 (0)
25 (5.4) 2450 (5.1)
Data Source The American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database was queried to perform this study. ACS-NSQIP is the largest surgical quality outcomes database in the United States and receives data from >500 hospitals in the country.11 It collects data on patient demographic information, comorbidities, intraoperative variables, and 30-day postoperative complications for inpatient and outpatient procedures.12 Each hospital involved in the program assigns an ACS-trained surgical clinical reviewer to collect preoperative through 30-day postoperative data on randomly assigned patients.13 Patient Cohort Current Procedural Terminology (CPT) codes were used to include patients who underwent vertebral fusion procedures between 2009 and 2016 for compression fractures. After identifying the cohort of interest, the remaining CPT codes for all cases were examined, and patients who underwent concurrent major surgical procedures were excluded. International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) and International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) codes were examined in the remaining patients and used to exclude those who had a diagnosis unrelated to pathologic compression fractures. All included and excluded CPT codes are presented in Supplementary Table 1 All excluded ICD-9-CM and ICD-10-CM codes are presented in Supplementary Table 2.
Bold indicates P value < 0.05. Q, quartile.
431 (92.3) 0.001
<0.001
45,162 (93.1)
Posterior cervical fusion; , n (%)
Anterior cervical discectomy and fusion, n (%)
19 (12.2)
3 (0.6) 412 (0.8) 4
134 (85.9)
17 (3.6) 2071 (4.3)
2431 (5.0)
131 (28.1) 14,605 (30.1)
3
2
45,028 (93.2)
316 (67.7)
PATIENTS AND METHODS
31,403 (64.8) 1
0.904
WORLD NEUROSURGERY -: e1-e12, - 2019
predispose patients to a higher risk of fractures of the cervical or lumbar vertebrae (fragility fractures) secondary to metabolic abnormalities. Such fractures have been increasingly addressed by spinal fusion surgery.7-9 Fusion of the cervical or lumbar spine is one of the most common surgical procedures performed in the United States.10 In 2011, approximately 488,000 spinal fusion procedures were performed, which accounted for about 3.1% of all operating room procedures.10 Patients on dialysis represent a high-risk group for postoperative surgical complications and morbidity; however, it is unclear what the impact of dialysis is on surgical outcomes after spinal fusion. Hence, the objective of this study was to assess the impact of dialysis dependency as an independent predictor of 30day postoperative outcomes for patients undergoing cervical and lumbar spinal fusion procedures for pathologic compression fractures using a prospective national surgical registry.
0.004
0.029 426 (68.5) 110 (71.0) 110 (70.5) 31,293 (64.7)
0.028
0.747
14 (2.3) 7 (4.5) 7 (1.5) <0.001 529 (1.1) 7 (4.5) Levels, n (%)
Emergency, n (%)
522 (1.1)
0.005 118.5 (82.0e171.3) 131.0 (90.0e191.5) 116.0 (79.0e160.5) <0.001 114 (82e159) 131 (89.75e191.25)
524 (84.2)
114 (82e159) Operative time (minutes), median (Q1eQ3)
607 (97.6)
150 (96.8) 374 (80.1) <0.001 37,837 (78.0) 151 (96.8) 37,686 (78.0)
140 (90.3) 467 (100.0) <0.001 48,382 (99.8) 141 (90.4) 48,241 (99.8)
Inpatient, n (%)
Wound class 1 or 2, n (%)
1 (0.2) 1 (0.2) Not assigned
72 (0.1)
0 (0.0) 0 (0.0) 72 (0.1)
0 (0.0) 0 (0.0)
90 (14.5) 17 (3.6)
1 (0.0) 5 (moribund)
4 (life threatening)
1095 (2.3)
0 (0.0) 0 (0.0)
73 (47.1) 74 (47.4)
1 (0.0)
<0.001
IMPACT OF DIALYSIS ON 30-DAY OUTCOMES AFTER SPINAL FUSION
1021 (2.1)
<0.001
MOHAMMED ALI ALVI ET AL.
Patient Characteristics Patient demographics included age, sex, and race. Preoperative comorbidities of interest included body mass index (BMI), functional status, smoking status, weight loss (>10% within the last 6 months), diabetes, dyspnea, bleeding disorder, steroid use for a chronic condition, an open/infected wound, and preoperative blood transfusion. Operative variables included American Association of Anesthesiologists (ASA) class, wound class, inpatient/outpatient procedure, operative time, emergency procedure, number of operated levels, and procedure type (i.e., lumbar, anterior cervical discectomy and fusion, or posterior cervical fusion).
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ORIGINAL ARTICLE MOHAMMED ALI ALVI ET AL.
IMPACT OF DIALYSIS ON 30-DAY OUTCOMES AFTER SPINAL FUSION
Table 2. Multivariable Regression for Patients Undergoing Cervical Fusion for Operative Time, Length of Stay, and 30-Day Readmissions Operative Time
Variable Dialysis Male (vs. female)
Length of Stay
30-Day Readmissions
Regression Coefficient (95% CI)
P Value
Regression Coefficient (95% CI)
P Value
Odds Ratio (95% CI)
15.93 (0.4e31.5)
0.045
6.06 (4.64e7.48)
<0.001
1.07 (1.02e1.12)
12.82 (0.33 to 25.96)
0.056
NS
P Value 0.009
NS
Diabetes No
(Base)
Insulin
NS
0.08 (1.88 to 1.71)
0.92
1.07 (1.00e1.14)
0.03
Noninsulin
NS
1.44 (3.29 to 0.4)
0.12
1.00 (0.95e1.07)
0.83
Smoker
NS
NS
NS
Functional status Independent
(base)
Partially dependent
18.42 (8.56 to 45.4)
0.18
2.93 (0.064e5.22)
0.01
1.1 (1.02e1.19)
0.018
Totally dependent
4.1 (162 to 153.8)
0.96
7.7 (20.9 to 5.42)
0.25
0.88 (0.56e1.4)
0.61
Unknown
6.79 (84.21 to 97.8)
0.88
0.95 (0.73e1.23)
0.69
1.68 (9.29 to 5.92)
0.66
Ventilator dependent
NS
22.6 (8.36e36.87)
0.002
History of severe chronic obstructive pulmonary disease
NS
NS
Ascites
NS
History of congestive heart failure
48.6 (7.94 to 105.22)
Hypertension requiring medication
0.093
NS
NS
1.47 (1.06e2.03)
0.021
NS
1.14 (0.97e1.34)
0.12
0.68 (0.48 to 1.84)
NS
NS
0.25
NS
Disseminated cancer
NS
NS
NS
Steroid use for chronic condition
NS
NS
NS
Bleeding disorder
NS
1.21 (1.91 to 4.32)
0.45
NS
Preoperative transfusion
NS
17.6 (12.08e23.18)
<0.001
NS
Bold indicates P value < 0.05. CI, confidence interval; NS, not significant in the univariate analysis.
Primary Predictor Dialysis dependency was based on the DIALYSIS variable in the ACS-NSQIP database. This variable identifies patients who are currently on dialysis (preoperatively), according to the ACS-NSQIP Participant Use Data File.14 Outcomes Outcomes assessed included operative time, length of stay, 30-day readmissions, any 30-day complications, serious 30-day complications, any return to operating room (ROR), and related ROR. Any complications and serious complications were designated according to the ACS-NSQIP Risk Calculator.15 Any complications represented a patient who experienced 1 of superficial incisional surgical site infection (SSI), deep incisional SSI, organ space SSI, wound disruption, pneumonia, unplanned intubation, pulmonary embolism, ventilation for >48 hours, progressive renal insufficiency, acute renal failure, urinary tract infection, stroke, cardiac arrest, myocardial infarction, deep vein thrombosis,
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reoperation, or systemic sepsis. Serious complications represented a patient who experienced 1 of cardiac arrest, myocardial infarction, pneumonia, progressive renal insufficiency, acute renal failure, pulmonary embolism, deep vein thrombosis, reoperation, deep incisional SSI, organ space SSI, systemic sepsis, unplanned intubation, urinary tract infection, or wound disruption. Related ROR was determined by examining the CPT codes for the reoperation in each cohort. Included CPT codes for related ROR are listed in Supplementary Table 3. Statistical Analysis Three-to-one propensity score matching was performed to account for confounding variables and to attenuate selection bias.16,17 Cases were matched based on age, sex, BMI, and number of operated levels. Patients with missing values for these variables were excluded before matching. Demographics, operative variables, and comorbidities were compared before and after matching between patients undergoing dialysis and patients not
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ORIGINAL ARTICLE MOHAMMED ALI ALVI ET AL.
IMPACT OF DIALYSIS ON 30-DAY OUTCOMES AFTER SPINAL FUSION
Table 3. Multivariable Regression for Patients Undergoing Cervical Fusion for Any Complications, Serious Complications, Any Return to Operating Room, and Related Return to Operating Room Any Complications Variable Dialysis
Serious Complications
Any Return to Operation Room OR (95% CI)
OR (95% CI)
P Value
OR (95% CI)
P Value
1.08 (1.03e1.13)
0.002
1.08 (1.02e1.14)
0.012
Related Return to Operation Room
P Value
OR (95% CI)
P Value 0.16
1.02 (0.98e1.05)
0.34
1.02 (0.99e1.06)
Male (vs. female)
NS
NS
1.03 (1.00e1.07)
0.074
NS
Age
NS
NS
NS
NS
Diabetes No
(Base)
Insulin
1.06 (1.00e1.13)
0.05
1.06 (0.99e1.14)
0.1
NS
NS
Noninsulin
0.99 (0.93e1.06)
0.85
0.98 (0.91e1.06)
0.66
NS
NS
NS
1.04 (1.01e1.07)
Smoker
NS
NS
0.016
Functional status Independent
(Base)
Partially dependent
1.08 (1.00e1.16)
0.061
1.04 (0.95e1.15)
0.37
NS
NS
Totally dependent
0.91 (0.58e1.41)
0.67
0.87 (0.51e1.49)
0.62
NS
NS
Unknown Ventilator dependent
0.94 (0.73e1.21)
0.62
0.9 (0.66e1.26)
0.5
2.55 (1.58e4.12)
<0.001
2.08 (1.17e3.72)
0.013
NS 2.30 (1.48e3.59)
NS <0.001
2.4 (1.63e3.5)
History of severe chronic obstructive pulmonary disease
NS
NS
NS
NS
Ascites
NS
NS
NS
NS
NS
NS
NS
NS
NS
1.24 (1.03e1.48)
History of congestive heart failure
1.11 (0.95e1.31)
0.18
NS
Hypertension requiring medication
1.00 (0.96e1.04)
0.97
1.02 (0.97e1.07)
Disseminated cancer Steroid use for chronic condition
NS
0.38
NS
NS
NS
NS
<0.001
0.021
NS
Bleeding disorder
1.31 (1.18e1.45)
<0.001
1.2 (1.07e1.37)
0.0035
1.10 (0.99e1.21)
0.08
NS
Preoperative transfusion
0.97 (0.81e1.17)
0.75
1.14 (0.91e1.43)
0.26
1.10 (0.9301.31)
0.27
1.1 (0.94e1.27)
0.24
Bold indicates P value < 0.05. OR, odds ratio; CI, confidence interval; NS, not significant in the univariate analysis.
undergoing dialysis while stratified by procedure type. These patient characteristics were compared between the dialysis and nondialysis groups by conducting a 2-sample t test for continuous variables and a c2 test for categorical variables to determine whether there was a significant difference between the means or categories, respectively, for each variable between the 2 groups.18 Multivariable conditional logistic regression was used to assess the association between dialysis and 30-day readmissions, any 30-day complications, serious 30-day complications, any ROR, and related ROR. Multivariable linear regression was used for the outcomes operative time and length of stay. Comorbidities significant for a given outcome on the univariate level were included in the multivariable regression. These analyses were performed on the matched cohort.19 Statistical analyses were conducted using R version 3.5.2 (R
WORLD NEUROSURGERY -: e1-e12, - 2019
Foundation for Statistical Computing, Vienna, Austria).20 P values <0.05 were considered to be statistically significant. RESULTS Cervical Fusion A total of 48,492 patients who underwent cervical fusion for a pathologic compression fracture were identified; 156 (0.32%) were on dialysis and 48,336 (99.68%) were not on dialysis. After matching, none of the variables matched on sex, age, BMI, and number of operated levels was statistically significant. A total of 155 patients on dialysis (25%) and 467 patients not on dialysis (75%) were analyzed after matching. Patients on dialysis were more likely to be African American (n ¼ 76, 49.0% vs. n ¼ 51,
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Unmatched No Dialysis (n [ 25,366)
Dialysis (n [ 51)
Age, median (Q1eQ3)
61 (51e69)
63 (56.5e67)
Male sex, n (%)
11,455 (45.2)
37 (72.5)
Matched Total (n [ 25,417)
P Value
No Dialysis (n [ 153)
Dialysis (n [ 51)
Total (n [ 204)
P Value
61 (51e69)
0.311
63 (56e70)
63 (56.5e67)
63 (56e69)
0.797
11,492 (45.2)
<0.001
112 (73.2)
37 (72.5)
149 (73)
0.927
Demographics
<0.001
Race, n (%) White
<0.001
21,008 (82.8)
22 (43.1)
21,030 (82.7)
123 (80.4)
22 (43.1)
145 (71.1)
1956 (7.7)
21 (41.2)
1977 (7.8)
12 (7.8)
1 (2.0)
33 (16.2)
Other
537 (2.1)
7 (13.7)
544 (2.1)
5 (3.3)
7 (13.7)
12 (5.9)
Unknown
1865 (7.4)
1 (2.0)
1866 (7.3)
13 (8.5)
1 (2.0)
14 (6.9)
29.9 (26.2e34.3)
29.8 (25.7e34.2)
29.9 (26.1e34.3)
28.3 (26.0e32.3)
29.8 (25.7e34.2)
28.7 (26.0e32.9)
Black or African American
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Table 4. Demographic, Preoperative, and Operative Variables for Unmatched and Matched Patients Undergoing Lumbar Fusion
Comorbidities
Independent
0.68 <0.001
Functional status, n (%)
0.21 0.004
24,652 (97.2)
44 (86.3)
24,696 (97.2)
149 (97.4)
44 (86.3)
193 (94.6)
Partially dependent
512 (2.0)
5 (9.8)
517 (2.0)
2 (2.6)
5 (9.8)
9 (4.4)
Totally dependent
49 (0.2)
2 (3.9)
51 (0.2)
0 (0.0)
2 (3.9)
2 (1.0)
153 (0.6)
0 (0.0)
153 (0.6)
2 (2.6)
0 (0.0)
2 (1.0)
5464 (21.5)
14 (27.5)
5478 (21.6)
0.31
39 (25.5)
14 (27.5)
53 (26.0)
0.782
Diabetes, n (%)
4404 (17.4)
22 (43.1)
4426 (17.4)
<0.001
31 (20.3)
22 (43.1)
53 (26.0)
<0.001
Steroid use, n (%)
1011 (4.0)
1 (2.0)
1012 (4.0)
0.46
4 (0.7)
1 (2.0)
5 (2.5)
0.794
Weight loss, n (%)
57 (0.2)
2 (3.9)
59 (0.2)
<0.001
1 (0.7)
2 (3.9)
3 (1.5)
0.093
Dyspnea, n (%)
1342 (5.3)
7 (13.7)
5.30%
<0.001
19 (6.5)
7 (13.7)
26 (12.7)
0.034
Bleeding disorder, n (%)
334 (1.3)
5 (9.8)
339 (1.3)
<0.001
3 (2.0)
5 (9.8)
8 (3.9)
0.012
Open wound/wound infection, n (%)
91 (0.4)
2 (3.9)
93 (0.4)
<0.001
3 (2.0)
2 (3.9)
5 (2.5)
0.433
Preoperative blood transfusion, n (%)
42 (0.2)
0 (0.0)
42 (0.2)
0.77
0 (0.0)
0 (0.0)
0 (0.0)
1
813 (3.2)
0 (0.0)
813 (3.2)
7 (4.6)
0 (0.0)
7 (3.4)
2 (mild disturbance)
12,320 (48.6)
3 (5.9)
12,323 (48.5)
64 (41.8)
3 (5.9)
67 (32.8)
3 (severe disturbance)
11,617 (45.8)
29 (56.9)
11,646 (45.8)
80 (52.3)
29 (56.9)
109 (53.4)
Operative <0.001
American Association of Anesthesiologists class, n (%) 1 (no disturbance)
<0.001
ORIGINAL ARTICLE
Unknown Smoke, n (%)
IMPACT OF DIALYSIS ON 30-DAY OUTCOMES AFTER SPINAL FUSION
WORLD NEUROSURGERY, https://doi.org/10.1016/j.wneu.2019.07.021
Body mass index, median (Q1eQ3)
ORIGINAL ARTICLE
0 (0) 0 (0) 64 (0.3)
0 (0)
6 (2.9)
1 (0.49) 0 (0.0) 233 (0.9)
2 (3.9) 4 (2.6)
1 (0.65)
1041 (4.1)
170 (83.3)
27 (13.2) 5 (9.8) 22 (14.4) 6240 (24.6)
44 (86.3) 126 (82.4) 17778 (69.9)
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Bold indicates P value < 0.05. Q, quartile.
64 (0.3) 5
0 (0.0)
233 (0.9) 4
0 (0.0)
1039 (4.1) 3
2 (3.9)
6235 (24.6)
5 (9.8)
17734 (69.9)
2
Levels, n (%)
1
44 (86.3)
0.62
0.51
10.9%; P < 0.001). They were also more likely to be disposed to comorbidities including worse functional status at presentation (dependent status, n ¼ 23, 14.8% vs. n ¼ 9, 1.9%; P < 0.001), diabetes (n ¼ 56, 36.1% vs. n ¼ 77, 16.5%; P < 0.001), bleeding disorder (n ¼ 18, 11.6% vs. n ¼ 2, 0.4%; P < 0.001), and preoperative blood transfusion (n ¼ 6, 3.9% vs. n ¼ 1, 0.2%; P < 0.001). In addition, they were more likely to have higher ASA grade (ASA 3 or 4, n ¼ 149, 96.1% vs. n ¼ 218, 46.7%; P < 0.001), higher wound class designation (wound class 3 or 4, n ¼ 15, 9.7%% vs. n ¼ 0, 0%; P < 0.001), more likely to be an inpatient (n ¼ 150, 96.8% vs. n ¼ 374, 80.1%; P < 0.01), and longer operative time (median time, 131.0 vs. 116.0 minutes; P ¼ 0.005). Unmatched and matched patient demographic, preoperative, and operative variables for the dialysis and nondialysis cohorts are listed in Table 1. On multivariable analysis, adjusted for an array of demographic characteristics and comorbidities, dialysis dependency was found to have a significant impact on operative time (regression coefficient [coef.], 15.93; 95% CI, 0.4e31.5; P ¼ 0.045), length of stay (coef., 6.06; 95% CI, 4.64e7.48; P < 0.001), 30-day readmissions (odds ratio [OR], 1.07; 95% CI, 1.02e1.12; P ¼ 0.009), any complications (OR, 1.08; 95% CI, 1.03e1.13; P ¼ 0.002), and serious complications (OR, 1.08; 95% CI, 1.02e1.14; P ¼ 0.012) for cervical fusions for pathologic compression fractures after propensity score matching. Dialysis dependency was not significantly associated with any ROR (OR, 1.02; 95% CI, 0.98e1.05; P ¼ 0.34) or related ROR (OR, 1.02; 95% CI, 0.98e1.05; P ¼ 0.16). Multivariable regression analyses are summarized in Tables 2 and 3.
0.631
1
0.211 199 (144.75e284.25)
0 (0.0) 0 (0.0)
0.086
0 (0.0)
212 (0.8)
0 (0.0)
206 (155e301.5)
IMPACT OF DIALYSIS ON 30-DAY OUTCOMES AFTER SPINAL FUSION
212 (0.8)
197 (143e268)
Emergency, n (%)
Operative time (minutes), median (Q1eQ3)
206 (155e301.5)
197 (143e268)
196 (136e273)
0.314 201 (98.5)
200 (98.0) 47 (92.2)
51 (100.0) 150 (98.0) 0.25 24,763 (97.4)
153 (100.0) <0.001 25,316 (99.6) 47 (92.2)
Inpatient, n (%)
51 (100.0)
25,269 (99.6)
24,712 (97.4)
Wound class 1 or 2, n (%)
0 (0.0) 0 (0.0) 43 (0.2) Not assigned
0 (0.0)
43 (0.2)
0 (0.0)
0 (0.0) 0 (0.0)
0 (0.0)
2 (1.3)
3 (0.0) 3 (0.0) 5 (moribund)
0 (0.0)
570 (2.2) 4 (life threatening)
19 (37.3)
589 (2.3)
19 (37.3)
21 (10.3)
<0.001
MOHAMMED ALI ALVI ET AL.
Lumbar Fusion A total of 25,417 patients who underwent lumbar fusion for a pathologic compression fracture were identified; 51 (0.2%) were on dialysis and 25,366 (99.8%) were not on dialysis. After matching, none of the variables matched on sex, age, BMI, and number of operated levels was statistically significant. A total of 51 patients on dialysis (25%) and 153 patients not on dialysis (75%) were analyzed after matching. Patients on dialysis were less likely to be white than were those not on dialysis (n ¼ 22; 43.1% vs. n ¼ 123, 80.4%; P < 0.001). They were also more likely be disposed to comorbidities such as diabetes (n ¼ 22; 43.1% vs. n ¼ 31, 20.3%; P < 0.001), a higher ASA grade (ASA 3 or 4, n ¼ 48, 94.1% vs. n ¼ 82, 53.6%; P < 0.001), and a higher wound class designation (wound class 3 or 4, n ¼ 4, 7.8% vs. n ¼ 0, 0%; P < 0.001). Unmatched and matched patient demographic, preoperative, and operative variables for the dialysis and nondialysis cohorts are listed in Table 4. On multivariable analysis adjusted for comorbidities, dialysis dependency was found to have a significant impact on length of stay (coef., 2.98; 95% CI, 1.28e4.68; P < 0.001) for lumbar fusions for pathologic compression fractures after propensity score matching. Dialysis dependency was not significantly associated with operative time (coef., 14.3; 95% CI, e23.5 to 52.1; P ¼ 0.46), 30-day readmissions (OR, 0.99; 95% CI, 0.91e1.07; P ¼ 0.79), any complications (OR, 0.98; 95% CI, 0.89e1.12; P ¼ 0.70), serious complications (OR, 0.99; 95% CI, 0.91e1.08; P ¼ 0.81), any ROR (OR, 0.97; 95% CI, 0.90e1.04; P ¼ 0.46), or related ROR (OR, 0.98; 95% CI, 0.94e1.02; P ¼ 0.25). Multivariable regression analyses are summarized in Tables 5 and 6.
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ORIGINAL ARTICLE MOHAMMED ALI ALVI ET AL.
IMPACT OF DIALYSIS ON 30-DAY OUTCOMES AFTER SPINAL FUSION
Table 5. Multivariable Regression for Patients Undergoing Lumbar Fusion for Operative Time, Length of Stay, and 30-Day Readmissions Operative Time
Length of Stay
30-Day Readmissions
Variable
Regression Coefficient (95% CI)
P Value
Regression Coefficient (95% CI)
P Value
Odds Ratio (95% CI)
P Value
Dialysis
14.3 (23.5 to 52.1)
0.46
2.98 (1.28e4.68)
<0.001
0.99 (0.91e1.07)
0.79
Male (vs. female)
NS
NS
NS
Age
NS
NS
NS
Diabetes No
(base)
Insulin
NS
2.73 (0.46e5.00)
0.019
NS
Noninsulin
NS
0.58 (1.44 to 2.59)
0.58
NS
Smoker
NS
NS
NS
Functional status Independent
(base)
Partially dependent
26.5 (e104.9 to 51.9)
0.51
6.35 (2.98e9.73)
<0.001
Totally dependent
239.7 (75.7e403.6)
0.005
21.79 (14.4e29.19)
<0.001
NS NS
Ventilator dependent
NS
NS
NS
History of severe chronic obstructive pulmonary disease
NS
NS
NS
NS
NS
Hypertension requiring medication
History of congestive heart failure
172.8 (11.2e334.5) NS
0.0037
NS
NS
Steroid use for chronic condition
NS
NS
1.4 (1.13e1.75)
Bleeding disorder
NS
1.68 (1.99 to 5.35)
0.37
0.003
NS
Bold indicates P value < 0.05. CI, confidence interval; NS, not significant in the univariate analysis.
DISCUSSION To our knowledge, this is the first study to assess the risks of dialysis dependency independent of comorbidities in a matched cohort analysis for patients undergoing cervical and lumbar fusions for pathologic compression fractures. Dialysis dependency was independently associated with longer operative time, higher length of stay, higher odds of 30-day readmissions, higher odds of any complications, and higher odds of serious complications for cervical fusion. It was also independently associated with increased length of stay for lumbar fusions. The impact of dialysis dependency on postoperative outcomes is increasingly relevant as health centers shift toward bundling payments and performance-based reimbursements in spine care.21,22 Our findings related to operative time and length of stay are particularly important; we found that dialysis may increase operative time by 15 minutes and length of stay by 6 days. This finding has several implications, the most important of which is increased associated health care costs.23,24 There is also significant variation in costs for spinal procedures within given diagnoses-related groups.25 Understanding outcomes for patients on dialysis will allow for more accurate risk stratification of patients for their impact on cost.
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Our findings are consistent with previous studies that show that dialysis dependency is significantly associated with adverse outcomes after surgery. Patients with CRF who are on dialysis have been previously shown to experience poorer bone strength and metabolism.3-5 This situation can lead to difficulties during surgical procedures and adverse postoperative outcomes. Hickson et al.4 identified 22,621 patients undergoing hip fracture repair from ACS-NSQIP between 2010 and 2013 and found that dialysis dependency was associated with prolonged postoperative stay past 7 days (OR, 1.43; CI, 1.51e3.48), higher in-hospital mortality (OR, 3.13; CI, 1.72e5.7), and 30-day death (OR, 2.29; CI, 1.51e3.48). Chung et al.26 and Chikuda et al.27 found that patients on dialysis had an increased risk of perioperative complications and mortality after elective lumbar surgery and various nonfusion spinal procedures, respectively. Inoue et al.28 studied 48 and 42 patients with dialysis undergoing cervical or lumbar spine posterior decompression, respectively, and found that patients on dialysis were more likely to have a higher rate of perioperative blood transfusions but similar postoperative outcomes. Chikawa et al.29 studied 33 chronic patients on hemodialysis with destructive spondyloarthropathy who underwent cervical or lumbar spinal surgeries and found that
WORLD NEUROSURGERY, https://doi.org/10.1016/j.wneu.2019.07.021
ORIGINAL ARTICLE MOHAMMED ALI ALVI ET AL.
IMPACT OF DIALYSIS ON 30-DAY OUTCOMES AFTER SPINAL FUSION
Table 6. Multivariable Regression for Patients Undergoing Lumbar Fusion for Any Complications, Serious Complications, Any Return to Operating Room, and Related Return to Operating Room Any Complications Variable Dialysis
Serious Complications
Any Return to Operation Room
Related Return to Operation Room
OR (95% CI)
P Value
OR (95% CI)
P Value
OR (95% CI)
P Value
OR (95% CI)
P Value
0.98 (0.89e1.12)
0.7
0.99 (0.91e1.08)
0.81
0.97 (0.9e1.04)
0.46
0.98 (0.94e1.02)
0.25
Male (vs. female)
NS
NS
NS
NS
Age
NS
NS
NS
NS
Diabetes No
(Base)
Insulin
1.11 (0.89e1.08)
0.103
NS
1.11 (1.00e1.23)
0.046
NS
Noninsulin
0.99 (0.88e1.11)
0.82
NS
1.00 (0.91e1.09)
0.95
NS
NS
NS
Smoker
NS
NS
Functional status Independent
(Base)
Partially dependent
1.12 (0.92e1.35)
0.26
1 (0.83e1.21)
0.97
0.95 (0.81e1.10)
0.48
NS
Totally dependent
1.42 (0.95e2.13)
0.09
1.56 (1.06e2.28)
0.025
1.46 (1.06e2.01)
0.023
NS
Ventilator dependent
2.16 (1.21e3.87)
0.01
2.08 (1.18e3.63)
0.011
NS
NS
History of severe chronic obstructive pulmonary disease
1.2 (1.00e1.44)
0.057
1.22 (1.02e1.46)
0.029
NS
1.09 (1.01e1.17)
History of congestive heart failure
1.44 (0.97e2.15)
0.08
1.4 (0.95e2.06)
0.091
NS
NS
Hypertension requiring medication
NS
NS
NS
NS
Steroid use for chronic condition
NS
NS
NS
NS
Bleeding disorder
NS
NS
NS
NS
0.026
Bold indicates P value < 0.05. OR, odds ratio; CI, confidence interval; NS, not significant in the univariate analysis.
spinal surgeries reliably obtain neurologic and functional improvement if preoperative inclusion criteria were correctly assessed by the surgeon. The results of our study provide additional information that spinal surgeons can use when considering the potential risks for dialysis-dependent patients considering cervical or lumbar fusion for their vertebral fractures. This factor can aid both groups in having thorough conversations about treatment options to optimize patient outcomes. Overall, the present study is one of the largest to assess the impact of dialysis on postoperative outcomes of patients undergoing cervical or lumbar fusion. However, there are some limitations to our study. Although the ACS-NSQIP database provides reliably collected information from medical institutions across the United States, its retrospective nature leads to inherent biases. It lacks some patient-specific factors that may act as unknown confounders when assessing 30-day quality outcomes. Data describing bone metabolism parameters related to CRF and preoperative timing of dialysis treatment are not provided in ACS-NSQIP.4 In addition, dialysis dependency may not adequately represent underlying differences in end-stage renal disease and its treatment
WORLD NEUROSURGERY -: e1-e12, - 2019
modalities (peritoneal vs. hemodialysis), when comparisons have been mixed for various outcomes.30 We also acknowledge the limitations associated with the low number of dialysis-dependent patients as well as the discrepancy in sample size between the dialysis and nondialysis groups; however, our numbers closely resemble the national prevalence of dialysis in United States. Moreover, using propensity score analysis to match the 2 groups enabled us to conduct meaningful analyses.16
CONCLUSIONS Our analyses indicate that dialysis dependency may have a significant adverse impact on 30-day postoperative outcomes among patients undergoing cervical and lumbar fusion for pathologic fractures. These findings suggest that dialysis dependency should be an important consideration for spine surgeons when deciding whether to perform a fusion procedure because it may assist them in having appropriate preoperative discussions with these patients to help optimize outcomes for this high-risk group.
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IMPACT OF DIALYSIS ON 30-DAY OUTCOMES AFTER SPINAL FUSION
12. Kerezoudis P, McCutcheon BA, Murphy M, et al. Predictors of 30-day perioperative morbidity and mortality of unruptured intracranial aneurysm surgery. Clin Neurol Neurosurg. 2016;149:75-80.
24. Hartman C, Hemphill C, Godzik J, et al. Analysis of cost and 30-day outcomes in single-level transforaminal lumbar interbody fusion and less invasive, stand-alone lateral transpsoas interbody fusion. World Neurosurg. 2019;122:e1037-e1040.
13. American College of Surgeons National Surgical Quality Improvement Program. About ACS NSQIP. Available at: https://www.facs.org/qualityprograms/acs-nsqip/about; 2019. Accessed April 18, 2019.
25. Ugiliweneza B, Kong M, Nosova K, et al. Spinal surgery: variations in health care costs and implications for episode-based bundled payments. Spine (Phila Pa 1976). 2014;39:1235-1242.
14. American College of Surgeons National Surgical Quality Improvement Program. ACS NSQIP Participant Use Data File. Available at: https:// www.facs.org/quality-programs/acs-nsqip/particip ant-use; 2019. Accessed April 21, 2019.
26. Chung AS, Campbell DH, Hustedt JW, Olmscheid N, Chutkan N. Inpatient outcomes in dialysis-dependent patients undergoing elective lumbar surgery for degenerative lumbar disease. Spine (Phila Pa 1976). 2017;42:1494-1501.
15. American College of Surgeons National Surgical Quality Improvement Program. About the ACS Risk Calculator. Available at: https:// riskcalculator.facs.org/RiskCalculator/about.html; 2019. Accessed April 21, 2019.
27. Chikuda H, Yasunaga H, Horiguchi H, et al. Mortality and morbidity in dialysis-dependent patients undergoing spinal surgery: analysis of a national administrative database in Japan. J Bone Joint Surg Am. 2012;94:433-438.
5. Sidibe A, Auguste D, Desbiens LC, et al. Fracture risk in dialysis and kidney transplanted patients: a systematic review. JBMR Plus. 2019;3:45-55.
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6. Rodriguez-Garcia M, Gomez-Alonso C, NavesDiaz M, Diaz-Lopez JB, Diaz-Corte C, CannataAndia JB. Vascular calcifications, vertebral fractures and mortality in haemodialysis patients. Nephrol Dial Transplant. 2009;24:239-246.
17. Wahood W, Yolcu Y, Alvi MA, Goyal A, Long TR, Bydon M. Assessing the differences in outcomes between general and non-general anesthesia in spine surgery: results from a national registry. Clin Neurol Neurosurg. 2019;180:79-86.
28. Inoue T, Mizutamari M, Fukuda K, Hatake K. Postoperative complications in dialysis-dependent patients undergoing elective decompression surgery without fusion or instrumentation for degenerative cervical or lumbar lesions. Spine (Phila Pa 1976). 2018;43:1169-1175.
7. Feng R, Finkelstein M, Bilal K, Oermann EK, Palese M, Caridi J. Trends and disparities in cervical spine fusion procedures utilization in the New York state. Spine (Phila Pa 1976). 2018;43: E601-E606.
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2. National Kidney Foundation. End Stage Renal Disease in the United States. Available at: https:// www.kidney.org/news/newsroom/factsheets/EndStage-Renal-Disease-in-the-US; 2016. Accessed April 19, 2019. 3. Trombetti A, Stoermann C, Chevalley T, et al. Alterations of bone microstructure and strength in end-stage renal failure. Osteoporos Int. 2013;24: 1721-1732. 4. Hickson LJ, Farah WH, Johnson RL, et al. Death and postoperative complications after hip fracture repair: dialysis effect. Kidney Int Rep. 2018;3: 1294-1303.
10. Weiss AJ, Elixhauser A, Andrews RM. Characteristics of operating room procedures in U.S. Hospitals, 2011: Statistical Brief #170. Rockville, MD: Healthcare Cost and Utilization Project; 2006. 11. Sebastian A, Goyal A, Alvi MA, et al. Assessing the performance of National Surgical Quality Improvement Program surgical risk calculator in elective spine surgery: insights from patients undergoing single-level posterior lumbar fusion [epub ahead of print] World Neurosurg. https://doi.org/10. 1016/j.wneu.2019.02.049, accessed May 20, 2019.
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29. Chikawa T, Sakai T, Bhatia NN, et al. Clinical outcomes of spinal surgery in patients treated with hemodialysis. J Spinal Disord Tech. 2013;26: 321-324. 30. Locatelli F, Marcelli D, Conte F, et al. Survival and development of cardiovascular disease by modality of treatment in patients with end-stage renal disease. J Am Soc Nephrol. 2001;12:2411-2417.
Conflict of interest statement: The authors declare that the article content was composed in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. Received 29 May 2019; accepted 1 July 2019
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Citation: World Neurosurg. (2019). https://doi.org/10.1016/j.wneu.2019.07.021 Journal homepage: www.journals.elsevier.com/worldneurosurgery Available online: www.sciencedirect.com 1878-8750/$ - see front matter ª 2019 Elsevier Inc. All rights reserved.
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ORIGINAL ARTICLE MOHAMMED ALI ALVI ET AL.
IMPACT OF DIALYSIS ON 30-DAY OUTCOMES AFTER SPINAL FUSION
SUPPLEMENTARY DATA
Supplementary Table 1. Current Procedural Terminology Codes: Included and Excluded Codes included Fusion
20930,20931, 20936, 20937, 20938, 22548, 22551, 22552, 22554, 22556, 22558, 22585, 22590, 22595, 22600, 22610, 22612, 22614, 22630, 22632, 22633, 22634, 22800, 22802, 22804, 22808, 22810, 22812, 22818, 22819, 22840, 22841, 22842, 22843, 22844, 22845, 22846, 22847, 22848, 22849, 22851, 22856, 22857, 22861, 22862
Cervical
22210, 22220, 22224, 22318, 22319, 22548, 22551, 22552, 22554, 22590, 22595, 22600, 22610, 22612, 22810, 61597, 63040, 63045, 63050, 63051, 63075, 63076, 63081, 63082, 63180, 63182, 63250, 63265, 63275, 63280, 63285, 63304, 63306, 22510
Lumbar
0163T, 0202T, 21610, 22010, 22015, 22206, 22207, 22212, 22214, 22216, 22222, 22520, 22521, 22523, 22524, 22525, 22532, 22533, 22534, 22556, 22586, 22632, 22633, 22634, 22804, 22812, 22818, 22819, 22847, 27280, 27282, 63001, 63003, 63005, 63011, 63012, 63015, 63016, 63017, 63020, 63030, 63035, 63042, 63043, 63044, 63046, 63047, 63048, 63055, 63056, 63057, 63064, 63066, 63077, 63078, 63101, 63102, 63103, 63170, 63251, 63252, 63266, 63267, 63271, 63272, 63273, 63276, 63277, 63278, 63281, 63282, 63287, 63290, 63302, 63303, 63305, 63307, 63710, 64714, 22208, 22514, 22522, 27279, 72133, 0171T, 0196T, 0221T, 22515, 52260, 62270, 62272, 62362, 63661, 63685, 64719, 64449
Anterior cervical discectomy and fusion
22551, 22554, 63075
Posterior cervical fusion;
22590, 22595, 22600
Codes excluded Fusion
10140, 22112, 27218, 29888, 39599, 61312, 20680, 27071, 31631, 35761, 41251, 63704, 21299, 15877, 44146, 20661, 25120, 29851, 61450, 21208, 35661, 11100, 29200, 10061, 36000, 40816, 27299,
10180, 11043, 11044, 15570, 15732, 15734, 19260, 19340, 19350, 19361, 19380, 20902, 20955, 21180, 21245, 22100, 22102, 22114, 22325, 22326, 22327, 23460, 23615, 24515, 24900, 25628, 27006, 27066, 27077, 27125, 27130, 27132, 27134, 27146, 27228, 27236, 27244, 27245, 27446, 27447, 27486, 27495, 27507, 27535, 27685, 27705, 27792, 27822, 27828, 28445, 29845, 32100, 32220, 32480, 32900, 33320, 35081, 35082, 35092, 35102, 35221, 35351, 35566, 35583, 35637, 35638, 35800, 35840, 42894, 45110, 45111, 49000, 49010, 49215, 49505, 49520, 49560, 50230, 51597, 56810, 57288, 60220, 60240, 60252, 60260, 61343, 61510, 61512, 61521, 61548, 61575, 62120, 62121, 69642, 69644, 13101, 13121, 13151, 15931, 19271, 19370, 20610, 20900, 21244, 21510, 21555, 21556, 21600, 21615, 21750, 21899, 21930, 22999, 23410, 23470, 23480, 23700, 25447, 25574, 27105, 27334, 27514, 27570, 27786, 28810, 29826, 31515, 31525, 31526, 31530, 31535, 31575, 31600, 31603, 31605, 31610, 31899, 32035, 32095, 32110, 32120, 32140, 32160, 32440, 32500, 32999, 35188, 35201, 35216, 35226, 35231, 35281, 35286, 36005, 36010, 36620, 37181, 37617, 37620, 37650, 37660, 38230, 38505, 38510, 38542, 38720, 38724, 39010, 39501, 40810, 42180, 42720, 42725, 42826, 42900, 42953, 44020, 56625, 58100, 58120, 60500, 60520, 61526, 61624, 63088, 63286, 63688, 64718, 64721, 10060, 11471, 11606, 11971, 12034, 12035, 12037, 13100, 13132, 15220, 15936, 19357, 20005, 20920, 20926, 21501, 23430, 26989, 27498, 32124, 32150, 32225, 34203, 38525, 38564, 38999, 39000, 42140, 42440, 43100, 43410, 47600, 20962, 27080, 27216, 32820, 34151, 34421, 39400, 44120, 49900, 60000, 61576, 38115, 78800, 20251, 49905, 75650, 51045, 27001, 11400, 11402, 11403, 11406, 11900, 11900, 12004, 14060, 15770, 19318, 20225, 20240, 20245, 20250, 20525, 20615, 20665, 20670, 20694, 20922, 21110, 21127, 21181, 21925, 21935, 22101, 22305, 22310, 22315, 23044, 23520, 23600, 24579, 25350, 25545, 27065, 27067, 27070, 27090, 27170, 27179, 27215, 27284, 27600, 27645, 27829, 28103, 28420, 28820, 29830, 29876, 29877, 29882, 33851, 33877, 34201, 35131, 35371, 35261, 36200, 36430, 36600, 38200, 38240, 39200, 43239, 44799, 61500, 61711, 61795, 63283, 63615, 63655, 63660, 63702, 63706, 63740, 63741, 11404, 11954, 12031, 13120, 16035, 19101, 23405, 23630, 25825, 26080, 27033, 27047, 27050, 27076, 27187, 27380, 27602, 27695, 27840, 28240, 28415, 28455, 33210, 37206, 37565, 55845, 57410, 61055, 61530, 64802, 64818, 66250, 67015, 69000, 69910, 86891, 86900, 88233, 92547, 95956, 15839, 20550, 23130, 23140, 23146, 23155, 24105, 25210, 25605, 26370, 26530, 27194, 27614, 28106, 28220, 28465, 28630, 29840, 29879, 31225, 32405, 33820, 33845, 35820, 36014, 37205, 38500, 42806, 42950, 57250, 61501, 61703, 62142, 62146, 11200, 11401, 11421, 11772, 20600, 20974, 21310, 21557, 23020, 23585, 27087, 27140, 27676, 28400, 28585, 29305, 30930, 38241, 43030, 43415, 88300, 15876, 17999, 20206, 20950, 30117, 37204, 61345, 61458, 11420, 15852, 20200, 20205, 20910, 41150, 51705, 61107, 62100, 69930, 27702, 55840, 20605, 27345, 29345, 22856, 22857, 22858, 22861, 22862, 22864, 22865, 27472, 32503, 32666, 35879, 43644, 44602, 47562, 49203, 49561, 49585, 49587, 49999, 58570, 32505, 32550, 32551, 32601, 32651, 43200, 43235, 43300, 43420, 44005, 44604, 45330, 49020, 49650, 49652, 49904, 61608, 61619, 61781, 0095T, 0098T
Cervical
22556, 22558, 22610, 22612, 22614, 22633, 22800, 22802, 22804, 22808, 22810, 22810, 22812, 22848, 22849
Lumbar
None
WORLD NEUROSURGERY -: e1-e12, - 2019
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22110, 27158, 29881, 37799, 60270, 20660, 26055, 31622, 35701, 41250, 63700, 20969, 49255, 33802, 20650, 24579, 29848, 61304, 19371, 35341, 10120, 28899, 62223, 31720, 21550, 23929, 32650,
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ORIGINAL ARTICLE MOHAMMED ALI ALVI ET AL.
IMPACT OF DIALYSIS ON 30-DAY OUTCOMES AFTER SPINAL FUSION
Supplementary Table 2. All Excluded International Classification of Diseases, Ninth Revision, Clinical Modification and International Classification of Diseases, Tenth Revision, Clinical Modification Codes International Classification of Diseases, Ninth Revision, Clinical Modification
1985, 8054, 8052, 80502, 3241, 1983, 80506, 1702, 95203, 80505, 7217, 2253, 2254, 7200, 80507, 1984, 80501, 80500, 83905, 73008, 73018, 73200, 8064, 1922, 2392, 80605, 80508, 83920, 83906, 83908, 80504, 80503, 80600, 20300, 80625, 2132, 8058, 80608, 2375, 3492, 80603, 95200, 2159, 3249, 95205, 99859, 1719, 83904, 1923, 2386, 2380, 83903, 2397, 8056, 19889, 2157, 2158, 80500, 83901, 74782, 80500, 1991, 80604, 83900, 9051, 2148, 73319, 80609, 83921, 95200, 1709, 2259, 34400, 72691, 73381, 75552, 7802, 78079, 80606, 95204, 1706, 1929, 2252, 23771, 3361, 42731, 56731, 71538, 71598, 73312, 73322, 80624, 80629, 95209, 99644, 99663, 99709, 138, 1718, 185, 193, 20288, 72702, 72743, 72749, 73098, 73329, 73395, 78097, 7842, 83907, 95200, 95202, 99812, 99932, 1505, 1143, 1623, 1629, 1749, 1976, 19881, 20979, 2136, 2376, 2379, 2396, 23989, 2536, 27402, 34409, 3449, 3484, 34989, 3559, 4019, 4211, 431, 4353, 44024, 47824, 55221, 5531, 56211, 6224, 6828, 7135, 72612, 72888, 73000, 73000, 73088, 73711, 7402, 75617, 7674, 7812, 7907, 79092, 80514, 8053, 80601, 80628, 8069, 82021, 9072, 9522, 9528, E8781, V5417, V689, 1502, 1504, 3819, 1539, 1542, 1625, 1714, 1717, 1743, 1918, 1919, 1955, 1961, 1972, 1973, 19882, 2152, 2258, 226, 2281, 2298, 2373, 23773, 2389, 23981, 2411, 2419, 2449, 25022, 2572, 2724, 27489, 2749, 27651, 2809, 2851, 28521, 29181, 2967, 3383, 34402, 34404, 3535, 3551, 3561, 3569, 3962, 4011, 41071, 41401, 41519, 4241, 4275, 42833, 4321, 43491, 4359, 44021, 4564, 51851, 51889, 53909, 5409, 55091, 55321, 5559, 6111, 6121, 6183, 66564, 6822, 7092, 71616, 71918, 7235, 7282, 7285, 7311, 7324, 73314, 73315, 73316, 73342, 73733, 73742, 7383, 75551, 75613, 7564, 75651, 7724, 78031, 7854, 7962, 80602, 80607, 80619, 80621, 80627, 80635, 8065, 81342, 82002, 85202, 85221, 85226, 95201, 95206, 99662, V1052, V1081
International Classification of Diseases, Tenth Revision, Clinical Modification
A1781, A1789, A1801, C061, C3411, C3490, C412, C700, C701, C720, C729, C7900, C7931, C7949, C800, C801, G061, G062, G8254, M4200, M4202, M4204, M4205, M4212, M4216, M450, M452, M453, M454, M456, M457, M459, M4620, M4622, M4623, M4624, M4625, M4626, M4627, M4632, M4633, M4634, M4636, M4640, M4642, M4643, M4644, M4645, M4646, M4647, M4682, M4686, M4687, M4691, M4692, M4694, M4696, M4810, M4812, M4816, M4817, M4830, M4832, M4836, M4837, M4842XA, M4848XA, M4852XA, M4852XG, M4852XS, M4854XA, M4854XG, M4855XA, M4856XA, M4856XG, M4857XA, M4858XA, M8440XA, M8448XA, M8458XA, M8458XG, M8468XA, M8468XK, M8550, M8558, M86172, M8618, M8629, M8668, M868X8, M869, M889, M8938, Q762, Q763, Q76414, Q76415, Q7649, Q796, S065X1A, S066X0A, S12000A, S12000B, S12000K, S12001K, S1201XA, S1202XA, S1202XG, S12030A, S12040A, S12040K, S12090K, S12091A, S12100A, S12100G, S12100K, S12100S, S12101A, S12110A, S12110G, S12110K, S12111A, S12111G, S12111K, S12112A, S12112B, S12112K, S12120A, S12120G, S12120K, S12121A, S12121K, S1214XA, S12190A, S12190G, S12190K, S12200A, S12200S, S12290A, S12300A, S12300K, S12330A, S12390A, S12400A, S12400G, S12400K, S12401A, S12430A, S12430K, S1244XA, S12450A, S12490A, S12500A, S12500B, S12500K, S12500S, S12501A, S12530A, S12530G, S12590A, S12591A, S12600A, S12600G, S12600K, S12600S, S12601A, S12601S, S12630A, S12690A, S12690G, S128, S129XXA, S129XXD, S129XXS, S130XXA, S13100A, S13111A, S13120A, S13121A, S13140A, S13141A, S13150A, S13151A, S13151S, S13160A, S13160D, S13161A, S13161D, S13170A, S13171A, S13180A, S134XXA, S140XXA, S14101A, S14103A, S14104A, S14105A, S14106A, S14107A, S14109A, S14109S, S14113A, S14116A, S14121A, S14122A, S14123A, S14123S, S14124A, S14125A, S14126A, S14127A, S14129A, S14129D, S14133A, S14141D, S14152A, S14154A, S14155A, S21209A, S22000A, S22001S, S22008B, S22009A, S22009G, S22009S, S22010A, S22019A, S22029G, S22032A, S22039A, S22041A, S22050A, S22058A, S22059A, S22060A, S22061A, S22062A, S22068A, S22068D, S22069A, S22070A, S22071A, S22071K, S22078A, S22078G, S22080A, S22080D, S22080K, S22081A, S22081B, S22081S, S22082A, S22082B, S22082K, S22088A, S22089A, S22089D, S23111A, S23150A, S23161A, S23163A, S23171A, S24103A, S24104A, S24151A, S242XXS, S3200, S32000D, S32001A, S32001D, S32001K, S32009A, S32009K, S32009S, S32010A, S32010K, S32011A, S32011G, S32012A, S32018A, S32018K, S32019A, S32021A, S32022A, S32022K, S32028A, S32029A, S32030A, S32030G, S32031A, S32031K, S32032A, S32038A, S32039A, S32041A, S32042A, S32042K, S32048A, S32049A, S32050A, S32051A, S32058A, S32058K, S32059A, S32059K, S3210XA, S3215XA, S329XXA, S329XXK, S329XXS, S330XXA, S330XXD, S33100A, S33131A, S33141A, S3339XA, S3421XA, S42292A, S72001A, S72145A
Supplementary Table 3. Current Procedural Terminology Codes for Related Return to the Operating Room Lumbar
10180, 11042, 20680
Cervical
10140, 10180, 11043, 11044, 12020, 13160, 20680, 21501, 22010, 22551, 22600, 22830, 22840, 22849, 31600, 37600, 63045, 63081, 63740, 97597
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WORLD NEUROSURGERY, https://doi.org/10.1016/j.wneu.2019.07.021
Impact of Dialysis on 30-Day Outcomes After Spinal Fusion Surgery for Pathologic Fractures: Insights from a National Quality Registry Mohammed Ali Alvi1,2, Jad Zreik1,2, Waseem Wahood1,2, Anshit Goyal1,2, Brett A. Freedman3, Arjun S. Sebastian3, Mohamad Bydon1,2
BACKGROUND: Patients with chronic renal failure undergoing hemodialysis have been shown to have poor overall health, osteoporosis, and altered bone metabolism. However, the impact of hemodialysis on patient outcomes after spinal fusion remains unknown. We sought to assess the effect of dialysis on 30-day perioperative and postoperative outcomes after cervical and lumbar fusion for pathologic compression fractures.
-
METHODS: We queried the National Surgical Quality Improvement Program from 2009 to 2016 for patients undergoing cervical or lumbar fusion for compression fractures. Three-to-one propensity score matching using sex, age, body mass index, and number of operated levels was used to match patients not undergoing dialysis with those undergoing dialysis. Multivariable conditional regression was used to identify the association between dialysis and 30-day clinical outcomes, after adjusting for confounders.
-
RESULTS: A total of 48,492 patients undergoing cervical fusion were identified; 156 (0.32%) of these were on dialysis. On multivariable regression, dialysis dependency was associated with increased operative time (regression coefficient [coef.], 15.93; 95% CI, 0.4e31.5; P [ 0.045), length of stay (coef. 6.06; 95% CI, 4.64e7.48; P < 0.001), 30-day readmissions (odds ratio [OR], 1.07; 95% CI, 1.02e1.12;
-
Key words Cervical - Dialysis - Fusion - Lumbar - NSQIP - Spine - Surgery -
Abbreviations and Acronyms ACS-NSQIP: American College of Surgeons National Surgical Quality Improvement Program ASA: American Association of Anesthesiologists BMI: Body mass index Coef.: Regression coefficient CPT: Current Procedural Terminology CRF: Chronic renal failure ICD-9-CM: International Classification of Diseases, Ninth Revision, Clinical Modification
WORLD NEUROSURGERY -: e1-e12, - 2019
P [ 0.009), any complications (OR 1.08; 95% CI, 1.03e1.13; P [ 0.002), and serious complications (OR, 1.08; 95% CI, 1.02e1.14; P [ 0.012). A total of 25,417 patients undergoing lumbar fusion were identified; 51 of these (0.2%) were on dialysis. On multivariable regression, dialysis dependency was associated with significantly higher length of stay (coef. 2.98; 95% CI, 1.28e4.68; P < 0.001). CONCLUSIONS: Our analyses indicated that dialysis dependency is associated with poor perioperative and postoperative outcomes after cervical/lumbar fusion for pathologic compression fractures.
-
INTRODUCTION
C
hronic renal failure (CRF) is a major public health issue with increasing prevalence and debilitating associated morbidity.1 In the United States in 2015, >660,000 Americans were being treated for CRF, with 468,000 of those on dialysis.2 Patients with CRF often experience disturbances in mineral and bone metabolism, which can lead to altered bone microstructure and strength.1,3-5 As a result, these patients more often have poorer overall health, osteoporosis, and increased risk for bone fracture, including vertebral fractures.4-6 CRF may
ICD-10-CM: International Classification of Diseases, Tenth Revision, Clinical Modification OR: Odds ratio ROR: Return to operation room SSI: Surgical site infection From the 1Mayo Clinic Neuro-Informatics Laboratory and Departments of 2Neurologic Surgery and 3Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota, USA To whom correspondence should be addressed: Mohamad Bydon, M.D. [E-mail: [email protected]] Mohammed Ali Alvi and Jad Zreik contributed equally to the article. Citation: World Neurosurg. (2019). https://doi.org/10.1016/j.wneu.2019.07.021 Journal homepage: www.journals.elsevier.com/world-neurosurgery Available online: www.sciencedirect.com 1878-8750/$ - see front matter ª 2019 Elsevier Inc. All rights reserved.
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Unmatched No Dialysis (n [ 48336)
Dialysis (n [ 156)
Age (years), median (Q1eQ3)
54 (46e63)
Male sex, n (%)
23,962 (49.6)
Matched Total (n [ 48492)
P Value
No Dialysis (n [ 467)
Dialysis (n [ 155)
Total (n [ 622)
P Value
60 (55e66.25)
54 (46e63)
<0.001
60 (54e65)
60 (55e66.5)
60 (54e66)
0.376
101 (64.7)
24,063 (49.6)
<0.001
293 (62.7)
100 (64.5)
393 (63.2)
0.699
Demographics
<0.001
Race, n (%)
MOHAMMED ALI ALVI ET AL.
e2
Table 1. Demographic, Preoperative, and Operative Variables for Unmatched and Matched Patients Undergoing Cervical Fusion
<0.001
White
8521 (79.7)
62 (39.7)
38,583 (79.6)
361 (77.3)
62 (40.0)
423 (68)
Black or African American
5045 (10.4)
77 (49.4)
5122 (10.6)
51 (10.9)
76 (49.0)
127 (20.4)
Other
1354 (2.8)
8 (5.1)
1362 (2.8)
12 (3.6)
8 (5.2)
20 (3.2)
Unknown
3416 (7.1)
9 (5.8)
3425 (7.1)
43 (9.2)
9 (5.8)
52 (8.4)
29.3 (25.7e33.8)
27.8 (24.0e33.0)
29.3 (25.7e33.8)
27.9 (24.6e31.7)
27.8 (24.0e33.0)
27.9 (24.5e31.8)
Comorbidities
Independent
0.003 <0.001
Functional status, n (%)
<0.001
0.802 <0.001
47,093 (97.4)
121 (77.6)
47,214 (97.4)
456 (97.6)
120 (77.4)
576 (92.6)
Partially dependent
865 (1.8)
33 (21.2)
898 (1.9)
9 (1.9)
22 (21.3)
42 (6.8)
Totally dependent
95 (0.2)
1 (0.6)
96 (0.2)
0 (0.0)
1 (0.6)
1 (0.2)
283 (0.6)
1 (0.6)
284 (0.6)
2 (0.4)
1 (0.6)
3 (0.5)
13,670 (28.3)
45 (28.8)
13,715 (28.3)
0.88
145 (31.0)
45 (29.0)
190 (30.5)
0.637
Diabetes, n (%)
7648 (15.8)
57 (36.5)
7705 (15.9)
<0.001
77 (16.5)
56 (36.1)
133 (21.4)
<0.001
Steroid use, n (%)
1650 (3.4)
8 (5.1)
1658 (3.4)
0.239
20 (4.3)
8 (5.2)
28 (4.5)
0.648
Weight loss, n (%)
110 (0.2)
4 (2.6)
114 (0.2)
<0.001
2 (0.4)
4 (2.6)
6 (1.0)
0.018
Dyspnea, n (%)
2546 (5.3)
23 (14.7)
2569 (5.3)
<0.001
32 (6.9)
23 (14.8)
55 (8.8)
0.006
Bleeding disorder, n (%)
586 (1.2)
18 (11.5)
604 (1.2)
<0.001
2 (0.4)
18 (11.6)
20 (3.2)
<0.001
Open wound/wound infection, n (%)
196 (0.4)
4 (2.6)
200 (0.4)
<0.001
3 (0.6)
4 (2.6)
7 (1.1)
0.047
Preoperative blood transfusion, n (%)
44 (0.1)
6 (3.8)
50 (0.1)
<0.001
1 (0.2)
6 (3.9)
7 (1.1)
<0.001
1859 (3.8)
0 (0.0)
1859 (3.8)
11 (2.4)
0 (0.0)
11 (1.8)
2 (mild disturbance)
25,720 (53.2)
6 (3.8)
25,726 (53.1)
234 (50.1)
6 (3.0)
240 (38.6)
3 (severe disturbance)
19,663 (40.7)
76 (48.7)
19,739 (40.7)
204 (43.7)
76 (49.0)
280 (45.0)
Operative <0.001
American Association of Anesthesiologists class, n (%) 1 (no disturbance)
<0.001
ORIGINAL ARTICLE
Unknown Smoke, n (%)
IMPACT OF DIALYSIS ON 30-DAY OUTCOMES AFTER SPINAL FUSION
WORLD NEUROSURGERY, https://doi.org/10.1016/j.wneu.2019.07.021
Body mass index, median (Q1eQ3)
ORIGINAL ARTICLE
167 (26.8)
25 (4.0)
4 (0.6)
575 (92.4)
44 (7.1)
36 (23.2)
8 (5.2)
1 (0.6)
134 (86.5)
19 (12.3)
37 (23.7)
8 (5.1)
1 (0.6)
14,568 (30.1)
2063 (4.3)
412 (0)
25 (5.4) 2450 (5.1)
Data Source The American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database was queried to perform this study. ACS-NSQIP is the largest surgical quality outcomes database in the United States and receives data from >500 hospitals in the country.11 It collects data on patient demographic information, comorbidities, intraoperative variables, and 30-day postoperative complications for inpatient and outpatient procedures.12 Each hospital involved in the program assigns an ACS-trained surgical clinical reviewer to collect preoperative through 30-day postoperative data on randomly assigned patients.13 Patient Cohort Current Procedural Terminology (CPT) codes were used to include patients who underwent vertebral fusion procedures between 2009 and 2016 for compression fractures. After identifying the cohort of interest, the remaining CPT codes for all cases were examined, and patients who underwent concurrent major surgical procedures were excluded. International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) and International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) codes were examined in the remaining patients and used to exclude those who had a diagnosis unrelated to pathologic compression fractures. All included and excluded CPT codes are presented in Supplementary Table 1 All excluded ICD-9-CM and ICD-10-CM codes are presented in Supplementary Table 2.
Bold indicates P value < 0.05. Q, quartile.
431 (92.3) 0.001
<0.001
45,162 (93.1)
Posterior cervical fusion; , n (%)
Anterior cervical discectomy and fusion, n (%)
19 (12.2)
3 (0.6) 412 (0.8) 4
134 (85.9)
17 (3.6) 2071 (4.3)
2431 (5.0)
131 (28.1) 14,605 (30.1)
3
2
45,028 (93.2)
316 (67.7)
PATIENTS AND METHODS
31,403 (64.8) 1
0.904
WORLD NEUROSURGERY -: e1-e12, - 2019
predispose patients to a higher risk of fractures of the cervical or lumbar vertebrae (fragility fractures) secondary to metabolic abnormalities. Such fractures have been increasingly addressed by spinal fusion surgery.7-9 Fusion of the cervical or lumbar spine is one of the most common surgical procedures performed in the United States.10 In 2011, approximately 488,000 spinal fusion procedures were performed, which accounted for about 3.1% of all operating room procedures.10 Patients on dialysis represent a high-risk group for postoperative surgical complications and morbidity; however, it is unclear what the impact of dialysis is on surgical outcomes after spinal fusion. Hence, the objective of this study was to assess the impact of dialysis dependency as an independent predictor of 30day postoperative outcomes for patients undergoing cervical and lumbar spinal fusion procedures for pathologic compression fractures using a prospective national surgical registry.
0.004
0.029 426 (68.5) 110 (71.0) 110 (70.5) 31,293 (64.7)
0.028
0.747
14 (2.3) 7 (4.5) 7 (1.5) <0.001 529 (1.1) 7 (4.5) Levels, n (%)
Emergency, n (%)
522 (1.1)
0.005 118.5 (82.0e171.3) 131.0 (90.0e191.5) 116.0 (79.0e160.5) <0.001 114 (82e159) 131 (89.75e191.25)
524 (84.2)
114 (82e159) Operative time (minutes), median (Q1eQ3)
607 (97.6)
150 (96.8) 374 (80.1) <0.001 37,837 (78.0) 151 (96.8) 37,686 (78.0)
140 (90.3) 467 (100.0) <0.001 48,382 (99.8) 141 (90.4) 48,241 (99.8)
Inpatient, n (%)
Wound class 1 or 2, n (%)
1 (0.2) 1 (0.2) Not assigned
72 (0.1)
0 (0.0) 0 (0.0) 72 (0.1)
0 (0.0) 0 (0.0)
90 (14.5) 17 (3.6)
1 (0.0) 5 (moribund)
4 (life threatening)
1095 (2.3)
0 (0.0) 0 (0.0)
73 (47.1) 74 (47.4)
1 (0.0)
<0.001
IMPACT OF DIALYSIS ON 30-DAY OUTCOMES AFTER SPINAL FUSION
1021 (2.1)
<0.001
MOHAMMED ALI ALVI ET AL.
Patient Characteristics Patient demographics included age, sex, and race. Preoperative comorbidities of interest included body mass index (BMI), functional status, smoking status, weight loss (>10% within the last 6 months), diabetes, dyspnea, bleeding disorder, steroid use for a chronic condition, an open/infected wound, and preoperative blood transfusion. Operative variables included American Association of Anesthesiologists (ASA) class, wound class, inpatient/outpatient procedure, operative time, emergency procedure, number of operated levels, and procedure type (i.e., lumbar, anterior cervical discectomy and fusion, or posterior cervical fusion).
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ORIGINAL ARTICLE MOHAMMED ALI ALVI ET AL.
IMPACT OF DIALYSIS ON 30-DAY OUTCOMES AFTER SPINAL FUSION
Table 2. Multivariable Regression for Patients Undergoing Cervical Fusion for Operative Time, Length of Stay, and 30-Day Readmissions Operative Time
Variable Dialysis Male (vs. female)
Length of Stay
30-Day Readmissions
Regression Coefficient (95% CI)
P Value
Regression Coefficient (95% CI)
P Value
Odds Ratio (95% CI)
15.93 (0.4e31.5)
0.045
6.06 (4.64e7.48)
<0.001
1.07 (1.02e1.12)
12.82 (0.33 to 25.96)
0.056
NS
P Value 0.009
NS
Diabetes No
(Base)
Insulin
NS
0.08 (1.88 to 1.71)
0.92
1.07 (1.00e1.14)
0.03
Noninsulin
NS
1.44 (3.29 to 0.4)
0.12
1.00 (0.95e1.07)
0.83
Smoker
NS
NS
NS
Functional status Independent
(base)
Partially dependent
18.42 (8.56 to 45.4)
0.18
2.93 (0.064e5.22)
0.01
1.1 (1.02e1.19)
0.018
Totally dependent
4.1 (162 to 153.8)
0.96
7.7 (20.9 to 5.42)
0.25
0.88 (0.56e1.4)
0.61
Unknown
6.79 (84.21 to 97.8)
0.88
0.95 (0.73e1.23)
0.69
1.68 (9.29 to 5.92)
0.66
Ventilator dependent
NS
22.6 (8.36e36.87)
0.002
History of severe chronic obstructive pulmonary disease
NS
NS
Ascites
NS
History of congestive heart failure
48.6 (7.94 to 105.22)
Hypertension requiring medication
0.093
NS
NS
1.47 (1.06e2.03)
0.021
NS
1.14 (0.97e1.34)
0.12
0.68 (0.48 to 1.84)
NS
NS
0.25
NS
Disseminated cancer
NS
NS
NS
Steroid use for chronic condition
NS
NS
NS
Bleeding disorder
NS
1.21 (1.91 to 4.32)
0.45
NS
Preoperative transfusion
NS
17.6 (12.08e23.18)
<0.001
NS
Bold indicates P value < 0.05. CI, confidence interval; NS, not significant in the univariate analysis.
Primary Predictor Dialysis dependency was based on the DIALYSIS variable in the ACS-NSQIP database. This variable identifies patients who are currently on dialysis (preoperatively), according to the ACS-NSQIP Participant Use Data File.14 Outcomes Outcomes assessed included operative time, length of stay, 30-day readmissions, any 30-day complications, serious 30-day complications, any return to operating room (ROR), and related ROR. Any complications and serious complications were designated according to the ACS-NSQIP Risk Calculator.15 Any complications represented a patient who experienced 1 of superficial incisional surgical site infection (SSI), deep incisional SSI, organ space SSI, wound disruption, pneumonia, unplanned intubation, pulmonary embolism, ventilation for >48 hours, progressive renal insufficiency, acute renal failure, urinary tract infection, stroke, cardiac arrest, myocardial infarction, deep vein thrombosis,
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reoperation, or systemic sepsis. Serious complications represented a patient who experienced 1 of cardiac arrest, myocardial infarction, pneumonia, progressive renal insufficiency, acute renal failure, pulmonary embolism, deep vein thrombosis, reoperation, deep incisional SSI, organ space SSI, systemic sepsis, unplanned intubation, urinary tract infection, or wound disruption. Related ROR was determined by examining the CPT codes for the reoperation in each cohort. Included CPT codes for related ROR are listed in Supplementary Table 3. Statistical Analysis Three-to-one propensity score matching was performed to account for confounding variables and to attenuate selection bias.16,17 Cases were matched based on age, sex, BMI, and number of operated levels. Patients with missing values for these variables were excluded before matching. Demographics, operative variables, and comorbidities were compared before and after matching between patients undergoing dialysis and patients not
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ORIGINAL ARTICLE MOHAMMED ALI ALVI ET AL.
IMPACT OF DIALYSIS ON 30-DAY OUTCOMES AFTER SPINAL FUSION
Table 3. Multivariable Regression for Patients Undergoing Cervical Fusion for Any Complications, Serious Complications, Any Return to Operating Room, and Related Return to Operating Room Any Complications Variable Dialysis
Serious Complications
Any Return to Operation Room OR (95% CI)
OR (95% CI)
P Value
OR (95% CI)
P Value
1.08 (1.03e1.13)
0.002
1.08 (1.02e1.14)
0.012
Related Return to Operation Room
P Value
OR (95% CI)
P Value 0.16
1.02 (0.98e1.05)
0.34
1.02 (0.99e1.06)
Male (vs. female)
NS
NS
1.03 (1.00e1.07)
0.074
NS
Age
NS
NS
NS
NS
Diabetes No
(Base)
Insulin
1.06 (1.00e1.13)
0.05
1.06 (0.99e1.14)
0.1
NS
NS
Noninsulin
0.99 (0.93e1.06)
0.85
0.98 (0.91e1.06)
0.66
NS
NS
NS
1.04 (1.01e1.07)
Smoker
NS
NS
0.016
Functional status Independent
(Base)
Partially dependent
1.08 (1.00e1.16)
0.061
1.04 (0.95e1.15)
0.37
NS
NS
Totally dependent
0.91 (0.58e1.41)
0.67
0.87 (0.51e1.49)
0.62
NS
NS
Unknown Ventilator dependent
0.94 (0.73e1.21)
0.62
0.9 (0.66e1.26)
0.5
2.55 (1.58e4.12)
<0.001
2.08 (1.17e3.72)
0.013
NS 2.30 (1.48e3.59)
NS <0.001
2.4 (1.63e3.5)
History of severe chronic obstructive pulmonary disease
NS
NS
NS
NS
Ascites
NS
NS
NS
NS
NS
NS
NS
NS
NS
1.24 (1.03e1.48)
History of congestive heart failure
1.11 (0.95e1.31)
0.18
NS
Hypertension requiring medication
1.00 (0.96e1.04)
0.97
1.02 (0.97e1.07)
Disseminated cancer Steroid use for chronic condition
NS
0.38
NS
NS
NS
NS
<0.001
0.021
NS
Bleeding disorder
1.31 (1.18e1.45)
<0.001
1.2 (1.07e1.37)
0.0035
1.10 (0.99e1.21)
0.08
NS
Preoperative transfusion
0.97 (0.81e1.17)
0.75
1.14 (0.91e1.43)
0.26
1.10 (0.9301.31)
0.27
1.1 (0.94e1.27)
0.24
Bold indicates P value < 0.05. OR, odds ratio; CI, confidence interval; NS, not significant in the univariate analysis.
undergoing dialysis while stratified by procedure type. These patient characteristics were compared between the dialysis and nondialysis groups by conducting a 2-sample t test for continuous variables and a c2 test for categorical variables to determine whether there was a significant difference between the means or categories, respectively, for each variable between the 2 groups.18 Multivariable conditional logistic regression was used to assess the association between dialysis and 30-day readmissions, any 30-day complications, serious 30-day complications, any ROR, and related ROR. Multivariable linear regression was used for the outcomes operative time and length of stay. Comorbidities significant for a given outcome on the univariate level were included in the multivariable regression. These analyses were performed on the matched cohort.19 Statistical analyses were conducted using R version 3.5.2 (R
WORLD NEUROSURGERY -: e1-e12, - 2019
Foundation for Statistical Computing, Vienna, Austria).20 P values <0.05 were considered to be statistically significant. RESULTS Cervical Fusion A total of 48,492 patients who underwent cervical fusion for a pathologic compression fracture were identified; 156 (0.32%) were on dialysis and 48,336 (99.68%) were not on dialysis. After matching, none of the variables matched on sex, age, BMI, and number of operated levels was statistically significant. A total of 155 patients on dialysis (25%) and 467 patients not on dialysis (75%) were analyzed after matching. Patients on dialysis were more likely to be African American (n ¼ 76, 49.0% vs. n ¼ 51,
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Unmatched No Dialysis (n [ 25,366)
Dialysis (n [ 51)
Age, median (Q1eQ3)
61 (51e69)
63 (56.5e67)
Male sex, n (%)
11,455 (45.2)
37 (72.5)
Matched Total (n [ 25,417)
P Value
No Dialysis (n [ 153)
Dialysis (n [ 51)
Total (n [ 204)
P Value
61 (51e69)
0.311
63 (56e70)
63 (56.5e67)
63 (56e69)
0.797
11,492 (45.2)
<0.001
112 (73.2)
37 (72.5)
149 (73)
0.927
Demographics
<0.001
Race, n (%) White
<0.001
21,008 (82.8)
22 (43.1)
21,030 (82.7)
123 (80.4)
22 (43.1)
145 (71.1)
1956 (7.7)
21 (41.2)
1977 (7.8)
12 (7.8)
1 (2.0)
33 (16.2)
Other
537 (2.1)
7 (13.7)
544 (2.1)
5 (3.3)
7 (13.7)
12 (5.9)
Unknown
1865 (7.4)
1 (2.0)
1866 (7.3)
13 (8.5)
1 (2.0)
14 (6.9)
29.9 (26.2e34.3)
29.8 (25.7e34.2)
29.9 (26.1e34.3)
28.3 (26.0e32.3)
29.8 (25.7e34.2)
28.7 (26.0e32.9)
Black or African American
MOHAMMED ALI ALVI ET AL.
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Table 4. Demographic, Preoperative, and Operative Variables for Unmatched and Matched Patients Undergoing Lumbar Fusion
Comorbidities
Independent
0.68 <0.001
Functional status, n (%)
0.21 0.004
24,652 (97.2)
44 (86.3)
24,696 (97.2)
149 (97.4)
44 (86.3)
193 (94.6)
Partially dependent
512 (2.0)
5 (9.8)
517 (2.0)
2 (2.6)
5 (9.8)
9 (4.4)
Totally dependent
49 (0.2)
2 (3.9)
51 (0.2)
0 (0.0)
2 (3.9)
2 (1.0)
153 (0.6)
0 (0.0)
153 (0.6)
2 (2.6)
0 (0.0)
2 (1.0)
5464 (21.5)
14 (27.5)
5478 (21.6)
0.31
39 (25.5)
14 (27.5)
53 (26.0)
0.782
Diabetes, n (%)
4404 (17.4)
22 (43.1)
4426 (17.4)
<0.001
31 (20.3)
22 (43.1)
53 (26.0)
<0.001
Steroid use, n (%)
1011 (4.0)
1 (2.0)
1012 (4.0)
0.46
4 (0.7)
1 (2.0)
5 (2.5)
0.794
Weight loss, n (%)
57 (0.2)
2 (3.9)
59 (0.2)
<0.001
1 (0.7)
2 (3.9)
3 (1.5)
0.093
Dyspnea, n (%)
1342 (5.3)
7 (13.7)
5.30%
<0.001
19 (6.5)
7 (13.7)
26 (12.7)
0.034
Bleeding disorder, n (%)
334 (1.3)
5 (9.8)
339 (1.3)
<0.001
3 (2.0)
5 (9.8)
8 (3.9)
0.012
Open wound/wound infection, n (%)
91 (0.4)
2 (3.9)
93 (0.4)
<0.001
3 (2.0)
2 (3.9)
5 (2.5)
0.433
Preoperative blood transfusion, n (%)
42 (0.2)
0 (0.0)
42 (0.2)
0.77
0 (0.0)
0 (0.0)
0 (0.0)
1
813 (3.2)
0 (0.0)
813 (3.2)
7 (4.6)
0 (0.0)
7 (3.4)
2 (mild disturbance)
12,320 (48.6)
3 (5.9)
12,323 (48.5)
64 (41.8)
3 (5.9)
67 (32.8)
3 (severe disturbance)
11,617 (45.8)
29 (56.9)
11,646 (45.8)
80 (52.3)
29 (56.9)
109 (53.4)
Operative <0.001
American Association of Anesthesiologists class, n (%) 1 (no disturbance)
<0.001
ORIGINAL ARTICLE
Unknown Smoke, n (%)
IMPACT OF DIALYSIS ON 30-DAY OUTCOMES AFTER SPINAL FUSION
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Body mass index, median (Q1eQ3)
ORIGINAL ARTICLE
0 (0) 0 (0) 64 (0.3)
0 (0)
6 (2.9)
1 (0.49) 0 (0.0) 233 (0.9)
2 (3.9) 4 (2.6)
1 (0.65)
1041 (4.1)
170 (83.3)
27 (13.2) 5 (9.8) 22 (14.4) 6240 (24.6)
44 (86.3) 126 (82.4) 17778 (69.9)
WORLD NEUROSURGERY -: e1-e12, - 2019
Bold indicates P value < 0.05. Q, quartile.
64 (0.3) 5
0 (0.0)
233 (0.9) 4
0 (0.0)
1039 (4.1) 3
2 (3.9)
6235 (24.6)
5 (9.8)
17734 (69.9)
2
Levels, n (%)
1
44 (86.3)
0.62
0.51
10.9%; P < 0.001). They were also more likely to be disposed to comorbidities including worse functional status at presentation (dependent status, n ¼ 23, 14.8% vs. n ¼ 9, 1.9%; P < 0.001), diabetes (n ¼ 56, 36.1% vs. n ¼ 77, 16.5%; P < 0.001), bleeding disorder (n ¼ 18, 11.6% vs. n ¼ 2, 0.4%; P < 0.001), and preoperative blood transfusion (n ¼ 6, 3.9% vs. n ¼ 1, 0.2%; P < 0.001). In addition, they were more likely to have higher ASA grade (ASA 3 or 4, n ¼ 149, 96.1% vs. n ¼ 218, 46.7%; P < 0.001), higher wound class designation (wound class 3 or 4, n ¼ 15, 9.7%% vs. n ¼ 0, 0%; P < 0.001), more likely to be an inpatient (n ¼ 150, 96.8% vs. n ¼ 374, 80.1%; P < 0.01), and longer operative time (median time, 131.0 vs. 116.0 minutes; P ¼ 0.005). Unmatched and matched patient demographic, preoperative, and operative variables for the dialysis and nondialysis cohorts are listed in Table 1. On multivariable analysis, adjusted for an array of demographic characteristics and comorbidities, dialysis dependency was found to have a significant impact on operative time (regression coefficient [coef.], 15.93; 95% CI, 0.4e31.5; P ¼ 0.045), length of stay (coef., 6.06; 95% CI, 4.64e7.48; P < 0.001), 30-day readmissions (odds ratio [OR], 1.07; 95% CI, 1.02e1.12; P ¼ 0.009), any complications (OR, 1.08; 95% CI, 1.03e1.13; P ¼ 0.002), and serious complications (OR, 1.08; 95% CI, 1.02e1.14; P ¼ 0.012) for cervical fusions for pathologic compression fractures after propensity score matching. Dialysis dependency was not significantly associated with any ROR (OR, 1.02; 95% CI, 0.98e1.05; P ¼ 0.34) or related ROR (OR, 1.02; 95% CI, 0.98e1.05; P ¼ 0.16). Multivariable regression analyses are summarized in Tables 2 and 3.
0.631
1
0.211 199 (144.75e284.25)
0 (0.0) 0 (0.0)
0.086
0 (0.0)
212 (0.8)
0 (0.0)
206 (155e301.5)
IMPACT OF DIALYSIS ON 30-DAY OUTCOMES AFTER SPINAL FUSION
212 (0.8)
197 (143e268)
Emergency, n (%)
Operative time (minutes), median (Q1eQ3)
206 (155e301.5)
197 (143e268)
196 (136e273)
0.314 201 (98.5)
200 (98.0) 47 (92.2)
51 (100.0) 150 (98.0) 0.25 24,763 (97.4)
153 (100.0) <0.001 25,316 (99.6) 47 (92.2)
Inpatient, n (%)
51 (100.0)
25,269 (99.6)
24,712 (97.4)
Wound class 1 or 2, n (%)
0 (0.0) 0 (0.0) 43 (0.2) Not assigned
0 (0.0)
43 (0.2)
0 (0.0)
0 (0.0) 0 (0.0)
0 (0.0)
2 (1.3)
3 (0.0) 3 (0.0) 5 (moribund)
0 (0.0)
570 (2.2) 4 (life threatening)
19 (37.3)
589 (2.3)
19 (37.3)
21 (10.3)
<0.001
MOHAMMED ALI ALVI ET AL.
Lumbar Fusion A total of 25,417 patients who underwent lumbar fusion for a pathologic compression fracture were identified; 51 (0.2%) were on dialysis and 25,366 (99.8%) were not on dialysis. After matching, none of the variables matched on sex, age, BMI, and number of operated levels was statistically significant. A total of 51 patients on dialysis (25%) and 153 patients not on dialysis (75%) were analyzed after matching. Patients on dialysis were less likely to be white than were those not on dialysis (n ¼ 22; 43.1% vs. n ¼ 123, 80.4%; P < 0.001). They were also more likely be disposed to comorbidities such as diabetes (n ¼ 22; 43.1% vs. n ¼ 31, 20.3%; P < 0.001), a higher ASA grade (ASA 3 or 4, n ¼ 48, 94.1% vs. n ¼ 82, 53.6%; P < 0.001), and a higher wound class designation (wound class 3 or 4, n ¼ 4, 7.8% vs. n ¼ 0, 0%; P < 0.001). Unmatched and matched patient demographic, preoperative, and operative variables for the dialysis and nondialysis cohorts are listed in Table 4. On multivariable analysis adjusted for comorbidities, dialysis dependency was found to have a significant impact on length of stay (coef., 2.98; 95% CI, 1.28e4.68; P < 0.001) for lumbar fusions for pathologic compression fractures after propensity score matching. Dialysis dependency was not significantly associated with operative time (coef., 14.3; 95% CI, e23.5 to 52.1; P ¼ 0.46), 30-day readmissions (OR, 0.99; 95% CI, 0.91e1.07; P ¼ 0.79), any complications (OR, 0.98; 95% CI, 0.89e1.12; P ¼ 0.70), serious complications (OR, 0.99; 95% CI, 0.91e1.08; P ¼ 0.81), any ROR (OR, 0.97; 95% CI, 0.90e1.04; P ¼ 0.46), or related ROR (OR, 0.98; 95% CI, 0.94e1.02; P ¼ 0.25). Multivariable regression analyses are summarized in Tables 5 and 6.
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ORIGINAL ARTICLE MOHAMMED ALI ALVI ET AL.
IMPACT OF DIALYSIS ON 30-DAY OUTCOMES AFTER SPINAL FUSION
Table 5. Multivariable Regression for Patients Undergoing Lumbar Fusion for Operative Time, Length of Stay, and 30-Day Readmissions Operative Time
Length of Stay
30-Day Readmissions
Variable
Regression Coefficient (95% CI)
P Value
Regression Coefficient (95% CI)
P Value
Odds Ratio (95% CI)
P Value
Dialysis
14.3 (23.5 to 52.1)
0.46
2.98 (1.28e4.68)
<0.001
0.99 (0.91e1.07)
0.79
Male (vs. female)
NS
NS
NS
Age
NS
NS
NS
Diabetes No
(base)
Insulin
NS
2.73 (0.46e5.00)
0.019
NS
Noninsulin
NS
0.58 (1.44 to 2.59)
0.58
NS
Smoker
NS
NS
NS
Functional status Independent
(base)
Partially dependent
26.5 (e104.9 to 51.9)
0.51
6.35 (2.98e9.73)
<0.001
Totally dependent
239.7 (75.7e403.6)
0.005
21.79 (14.4e29.19)
<0.001
NS NS
Ventilator dependent
NS
NS
NS
History of severe chronic obstructive pulmonary disease
NS
NS
NS
NS
NS
Hypertension requiring medication
History of congestive heart failure
172.8 (11.2e334.5) NS
0.0037
NS
NS
Steroid use for chronic condition
NS
NS
1.4 (1.13e1.75)
Bleeding disorder
NS
1.68 (1.99 to 5.35)
0.37
0.003
NS
Bold indicates P value < 0.05. CI, confidence interval; NS, not significant in the univariate analysis.
DISCUSSION To our knowledge, this is the first study to assess the risks of dialysis dependency independent of comorbidities in a matched cohort analysis for patients undergoing cervical and lumbar fusions for pathologic compression fractures. Dialysis dependency was independently associated with longer operative time, higher length of stay, higher odds of 30-day readmissions, higher odds of any complications, and higher odds of serious complications for cervical fusion. It was also independently associated with increased length of stay for lumbar fusions. The impact of dialysis dependency on postoperative outcomes is increasingly relevant as health centers shift toward bundling payments and performance-based reimbursements in spine care.21,22 Our findings related to operative time and length of stay are particularly important; we found that dialysis may increase operative time by 15 minutes and length of stay by 6 days. This finding has several implications, the most important of which is increased associated health care costs.23,24 There is also significant variation in costs for spinal procedures within given diagnoses-related groups.25 Understanding outcomes for patients on dialysis will allow for more accurate risk stratification of patients for their impact on cost.
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Our findings are consistent with previous studies that show that dialysis dependency is significantly associated with adverse outcomes after surgery. Patients with CRF who are on dialysis have been previously shown to experience poorer bone strength and metabolism.3-5 This situation can lead to difficulties during surgical procedures and adverse postoperative outcomes. Hickson et al.4 identified 22,621 patients undergoing hip fracture repair from ACS-NSQIP between 2010 and 2013 and found that dialysis dependency was associated with prolonged postoperative stay past 7 days (OR, 1.43; CI, 1.51e3.48), higher in-hospital mortality (OR, 3.13; CI, 1.72e5.7), and 30-day death (OR, 2.29; CI, 1.51e3.48). Chung et al.26 and Chikuda et al.27 found that patients on dialysis had an increased risk of perioperative complications and mortality after elective lumbar surgery and various nonfusion spinal procedures, respectively. Inoue et al.28 studied 48 and 42 patients with dialysis undergoing cervical or lumbar spine posterior decompression, respectively, and found that patients on dialysis were more likely to have a higher rate of perioperative blood transfusions but similar postoperative outcomes. Chikawa et al.29 studied 33 chronic patients on hemodialysis with destructive spondyloarthropathy who underwent cervical or lumbar spinal surgeries and found that
WORLD NEUROSURGERY, https://doi.org/10.1016/j.wneu.2019.07.021
ORIGINAL ARTICLE MOHAMMED ALI ALVI ET AL.
IMPACT OF DIALYSIS ON 30-DAY OUTCOMES AFTER SPINAL FUSION
Table 6. Multivariable Regression for Patients Undergoing Lumbar Fusion for Any Complications, Serious Complications, Any Return to Operating Room, and Related Return to Operating Room Any Complications Variable Dialysis
Serious Complications
Any Return to Operation Room
Related Return to Operation Room
OR (95% CI)
P Value
OR (95% CI)
P Value
OR (95% CI)
P Value
OR (95% CI)
P Value
0.98 (0.89e1.12)
0.7
0.99 (0.91e1.08)
0.81
0.97 (0.9e1.04)
0.46
0.98 (0.94e1.02)
0.25
Male (vs. female)
NS
NS
NS
NS
Age
NS
NS
NS
NS
Diabetes No
(Base)
Insulin
1.11 (0.89e1.08)
0.103
NS
1.11 (1.00e1.23)
0.046
NS
Noninsulin
0.99 (0.88e1.11)
0.82
NS
1.00 (0.91e1.09)
0.95
NS
NS
NS
Smoker
NS
NS
Functional status Independent
(Base)
Partially dependent
1.12 (0.92e1.35)
0.26
1 (0.83e1.21)
0.97
0.95 (0.81e1.10)
0.48
NS
Totally dependent
1.42 (0.95e2.13)
0.09
1.56 (1.06e2.28)
0.025
1.46 (1.06e2.01)
0.023
NS
Ventilator dependent
2.16 (1.21e3.87)
0.01
2.08 (1.18e3.63)
0.011
NS
NS
History of severe chronic obstructive pulmonary disease
1.2 (1.00e1.44)
0.057
1.22 (1.02e1.46)
0.029
NS
1.09 (1.01e1.17)
History of congestive heart failure
1.44 (0.97e2.15)
0.08
1.4 (0.95e2.06)
0.091
NS
NS
Hypertension requiring medication
NS
NS
NS
NS
Steroid use for chronic condition
NS
NS
NS
NS
Bleeding disorder
NS
NS
NS
NS
0.026
Bold indicates P value < 0.05. OR, odds ratio; CI, confidence interval; NS, not significant in the univariate analysis.
spinal surgeries reliably obtain neurologic and functional improvement if preoperative inclusion criteria were correctly assessed by the surgeon. The results of our study provide additional information that spinal surgeons can use when considering the potential risks for dialysis-dependent patients considering cervical or lumbar fusion for their vertebral fractures. This factor can aid both groups in having thorough conversations about treatment options to optimize patient outcomes. Overall, the present study is one of the largest to assess the impact of dialysis on postoperative outcomes of patients undergoing cervical or lumbar fusion. However, there are some limitations to our study. Although the ACS-NSQIP database provides reliably collected information from medical institutions across the United States, its retrospective nature leads to inherent biases. It lacks some patient-specific factors that may act as unknown confounders when assessing 30-day quality outcomes. Data describing bone metabolism parameters related to CRF and preoperative timing of dialysis treatment are not provided in ACS-NSQIP.4 In addition, dialysis dependency may not adequately represent underlying differences in end-stage renal disease and its treatment
WORLD NEUROSURGERY -: e1-e12, - 2019
modalities (peritoneal vs. hemodialysis), when comparisons have been mixed for various outcomes.30 We also acknowledge the limitations associated with the low number of dialysis-dependent patients as well as the discrepancy in sample size between the dialysis and nondialysis groups; however, our numbers closely resemble the national prevalence of dialysis in United States. Moreover, using propensity score analysis to match the 2 groups enabled us to conduct meaningful analyses.16
CONCLUSIONS Our analyses indicate that dialysis dependency may have a significant adverse impact on 30-day postoperative outcomes among patients undergoing cervical and lumbar fusion for pathologic fractures. These findings suggest that dialysis dependency should be an important consideration for spine surgeons when deciding whether to perform a fusion procedure because it may assist them in having appropriate preoperative discussions with these patients to help optimize outcomes for this high-risk group.
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IMPACT OF DIALYSIS ON 30-DAY OUTCOMES AFTER SPINAL FUSION
12. Kerezoudis P, McCutcheon BA, Murphy M, et al. Predictors of 30-day perioperative morbidity and mortality of unruptured intracranial aneurysm surgery. Clin Neurol Neurosurg. 2016;149:75-80.
24. Hartman C, Hemphill C, Godzik J, et al. Analysis of cost and 30-day outcomes in single-level transforaminal lumbar interbody fusion and less invasive, stand-alone lateral transpsoas interbody fusion. World Neurosurg. 2019;122:e1037-e1040.
13. American College of Surgeons National Surgical Quality Improvement Program. About ACS NSQIP. Available at: https://www.facs.org/qualityprograms/acs-nsqip/about; 2019. Accessed April 18, 2019.
25. Ugiliweneza B, Kong M, Nosova K, et al. Spinal surgery: variations in health care costs and implications for episode-based bundled payments. Spine (Phila Pa 1976). 2014;39:1235-1242.
14. American College of Surgeons National Surgical Quality Improvement Program. ACS NSQIP Participant Use Data File. Available at: https:// www.facs.org/quality-programs/acs-nsqip/particip ant-use; 2019. Accessed April 21, 2019.
26. Chung AS, Campbell DH, Hustedt JW, Olmscheid N, Chutkan N. Inpatient outcomes in dialysis-dependent patients undergoing elective lumbar surgery for degenerative lumbar disease. Spine (Phila Pa 1976). 2017;42:1494-1501.
15. American College of Surgeons National Surgical Quality Improvement Program. About the ACS Risk Calculator. Available at: https:// riskcalculator.facs.org/RiskCalculator/about.html; 2019. Accessed April 21, 2019.
27. Chikuda H, Yasunaga H, Horiguchi H, et al. Mortality and morbidity in dialysis-dependent patients undergoing spinal surgery: analysis of a national administrative database in Japan. J Bone Joint Surg Am. 2012;94:433-438.
5. Sidibe A, Auguste D, Desbiens LC, et al. Fracture risk in dialysis and kidney transplanted patients: a systematic review. JBMR Plus. 2019;3:45-55.
16. D’Agostino RB Jr. Propensity score methods for bias reduction in the comparison of a treatment to a non-randomized control group. Stat Med. 1998; 17:2265-2281.
6. Rodriguez-Garcia M, Gomez-Alonso C, NavesDiaz M, Diaz-Lopez JB, Diaz-Corte C, CannataAndia JB. Vascular calcifications, vertebral fractures and mortality in haemodialysis patients. Nephrol Dial Transplant. 2009;24:239-246.
17. Wahood W, Yolcu Y, Alvi MA, Goyal A, Long TR, Bydon M. Assessing the differences in outcomes between general and non-general anesthesia in spine surgery: results from a national registry. Clin Neurol Neurosurg. 2019;180:79-86.
28. Inoue T, Mizutamari M, Fukuda K, Hatake K. Postoperative complications in dialysis-dependent patients undergoing elective decompression surgery without fusion or instrumentation for degenerative cervical or lumbar lesions. Spine (Phila Pa 1976). 2018;43:1169-1175.
7. Feng R, Finkelstein M, Bilal K, Oermann EK, Palese M, Caridi J. Trends and disparities in cervical spine fusion procedures utilization in the New York state. Spine (Phila Pa 1976). 2018;43: E601-E606.
18. Austin PC. Comparing paired vs non-paired statistical methods of analyses when making inferences about absolute risk reductions in propensity-score matched samples. Stat Med. 2011;30:1292-1301.
8. Drazin D, Nuno M, Shweikeh F, et al. Outcomes and national trends for the surgical treatment of lumbar spine trauma. Biomed Res Int. 2016;2016, 3623875.
19. Breslow NE, Day NE, Halvorsen KT, Prentice RL, Sabai C. Estimation of multiple relative risk functions in matched case-control studies. Am J Epidemiol. 1978;108:299-307.
9. Rajaee SS, Bae HW, Kanim LE, Delamarter RB. Spinal fusion in the United States: analysis of trends from 1998 to 2008. Spine (Phila Pa 1976). 2012;37:67-76.
20. R Core Team. R. A language and environment for statistical computing. Available at: https://www. R-project.org; 2018. Accessed January 10, 2019.
2. National Kidney Foundation. End Stage Renal Disease in the United States. Available at: https:// www.kidney.org/news/newsroom/factsheets/EndStage-Renal-Disease-in-the-US; 2016. Accessed April 19, 2019. 3. Trombetti A, Stoermann C, Chevalley T, et al. Alterations of bone microstructure and strength in end-stage renal failure. Osteoporos Int. 2013;24: 1721-1732. 4. Hickson LJ, Farah WH, Johnson RL, et al. Death and postoperative complications after hip fracture repair: dialysis effect. Kidney Int Rep. 2018;3: 1294-1303.
10. Weiss AJ, Elixhauser A, Andrews RM. Characteristics of operating room procedures in U.S. Hospitals, 2011: Statistical Brief #170. Rockville, MD: Healthcare Cost and Utilization Project; 2006. 11. Sebastian A, Goyal A, Alvi MA, et al. Assessing the performance of National Surgical Quality Improvement Program surgical risk calculator in elective spine surgery: insights from patients undergoing single-level posterior lumbar fusion [epub ahead of print] World Neurosurg. https://doi.org/10. 1016/j.wneu.2019.02.049, accessed May 20, 2019.
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29. Chikawa T, Sakai T, Bhatia NN, et al. Clinical outcomes of spinal surgery in patients treated with hemodialysis. J Spinal Disord Tech. 2013;26: 321-324. 30. Locatelli F, Marcelli D, Conte F, et al. Survival and development of cardiovascular disease by modality of treatment in patients with end-stage renal disease. J Am Soc Nephrol. 2001;12:2411-2417.
Conflict of interest statement: The authors declare that the article content was composed in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. Received 29 May 2019; accepted 1 July 2019
21. Kazberouk A, McGuire K, Landon BE. A survey of innovative reimbursement models in spine care. Spine (Phila Pa 1976). 2016;41:344-352. 22. Manchikanti L, Caraway DL, Parr AT, Fellows B, Hirsch JA. Patient Protection and Affordable Care Act of 2010: reforming the health care reform for the new decade. Pain Physician. 2011;14:E35-E67.
Citation: World Neurosurg. (2019). https://doi.org/10.1016/j.wneu.2019.07.021 Journal homepage: www.journals.elsevier.com/worldneurosurgery Available online: www.sciencedirect.com 1878-8750/$ - see front matter ª 2019 Elsevier Inc. All rights reserved.
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ORIGINAL ARTICLE MOHAMMED ALI ALVI ET AL.
IMPACT OF DIALYSIS ON 30-DAY OUTCOMES AFTER SPINAL FUSION
SUPPLEMENTARY DATA
Supplementary Table 1. Current Procedural Terminology Codes: Included and Excluded Codes included Fusion
20930,20931, 20936, 20937, 20938, 22548, 22551, 22552, 22554, 22556, 22558, 22585, 22590, 22595, 22600, 22610, 22612, 22614, 22630, 22632, 22633, 22634, 22800, 22802, 22804, 22808, 22810, 22812, 22818, 22819, 22840, 22841, 22842, 22843, 22844, 22845, 22846, 22847, 22848, 22849, 22851, 22856, 22857, 22861, 22862
Cervical
22210, 22220, 22224, 22318, 22319, 22548, 22551, 22552, 22554, 22590, 22595, 22600, 22610, 22612, 22810, 61597, 63040, 63045, 63050, 63051, 63075, 63076, 63081, 63082, 63180, 63182, 63250, 63265, 63275, 63280, 63285, 63304, 63306, 22510
Lumbar
0163T, 0202T, 21610, 22010, 22015, 22206, 22207, 22212, 22214, 22216, 22222, 22520, 22521, 22523, 22524, 22525, 22532, 22533, 22534, 22556, 22586, 22632, 22633, 22634, 22804, 22812, 22818, 22819, 22847, 27280, 27282, 63001, 63003, 63005, 63011, 63012, 63015, 63016, 63017, 63020, 63030, 63035, 63042, 63043, 63044, 63046, 63047, 63048, 63055, 63056, 63057, 63064, 63066, 63077, 63078, 63101, 63102, 63103, 63170, 63251, 63252, 63266, 63267, 63271, 63272, 63273, 63276, 63277, 63278, 63281, 63282, 63287, 63290, 63302, 63303, 63305, 63307, 63710, 64714, 22208, 22514, 22522, 27279, 72133, 0171T, 0196T, 0221T, 22515, 52260, 62270, 62272, 62362, 63661, 63685, 64719, 64449
Anterior cervical discectomy and fusion
22551, 22554, 63075
Posterior cervical fusion;
22590, 22595, 22600
Codes excluded Fusion
10140, 22112, 27218, 29888, 39599, 61312, 20680, 27071, 31631, 35761, 41251, 63704, 21299, 15877, 44146, 20661, 25120, 29851, 61450, 21208, 35661, 11100, 29200, 10061, 36000, 40816, 27299,
10180, 11043, 11044, 15570, 15732, 15734, 19260, 19340, 19350, 19361, 19380, 20902, 20955, 21180, 21245, 22100, 22102, 22114, 22325, 22326, 22327, 23460, 23615, 24515, 24900, 25628, 27006, 27066, 27077, 27125, 27130, 27132, 27134, 27146, 27228, 27236, 27244, 27245, 27446, 27447, 27486, 27495, 27507, 27535, 27685, 27705, 27792, 27822, 27828, 28445, 29845, 32100, 32220, 32480, 32900, 33320, 35081, 35082, 35092, 35102, 35221, 35351, 35566, 35583, 35637, 35638, 35800, 35840, 42894, 45110, 45111, 49000, 49010, 49215, 49505, 49520, 49560, 50230, 51597, 56810, 57288, 60220, 60240, 60252, 60260, 61343, 61510, 61512, 61521, 61548, 61575, 62120, 62121, 69642, 69644, 13101, 13121, 13151, 15931, 19271, 19370, 20610, 20900, 21244, 21510, 21555, 21556, 21600, 21615, 21750, 21899, 21930, 22999, 23410, 23470, 23480, 23700, 25447, 25574, 27105, 27334, 27514, 27570, 27786, 28810, 29826, 31515, 31525, 31526, 31530, 31535, 31575, 31600, 31603, 31605, 31610, 31899, 32035, 32095, 32110, 32120, 32140, 32160, 32440, 32500, 32999, 35188, 35201, 35216, 35226, 35231, 35281, 35286, 36005, 36010, 36620, 37181, 37617, 37620, 37650, 37660, 38230, 38505, 38510, 38542, 38720, 38724, 39010, 39501, 40810, 42180, 42720, 42725, 42826, 42900, 42953, 44020, 56625, 58100, 58120, 60500, 60520, 61526, 61624, 63088, 63286, 63688, 64718, 64721, 10060, 11471, 11606, 11971, 12034, 12035, 12037, 13100, 13132, 15220, 15936, 19357, 20005, 20920, 20926, 21501, 23430, 26989, 27498, 32124, 32150, 32225, 34203, 38525, 38564, 38999, 39000, 42140, 42440, 43100, 43410, 47600, 20962, 27080, 27216, 32820, 34151, 34421, 39400, 44120, 49900, 60000, 61576, 38115, 78800, 20251, 49905, 75650, 51045, 27001, 11400, 11402, 11403, 11406, 11900, 11900, 12004, 14060, 15770, 19318, 20225, 20240, 20245, 20250, 20525, 20615, 20665, 20670, 20694, 20922, 21110, 21127, 21181, 21925, 21935, 22101, 22305, 22310, 22315, 23044, 23520, 23600, 24579, 25350, 25545, 27065, 27067, 27070, 27090, 27170, 27179, 27215, 27284, 27600, 27645, 27829, 28103, 28420, 28820, 29830, 29876, 29877, 29882, 33851, 33877, 34201, 35131, 35371, 35261, 36200, 36430, 36600, 38200, 38240, 39200, 43239, 44799, 61500, 61711, 61795, 63283, 63615, 63655, 63660, 63702, 63706, 63740, 63741, 11404, 11954, 12031, 13120, 16035, 19101, 23405, 23630, 25825, 26080, 27033, 27047, 27050, 27076, 27187, 27380, 27602, 27695, 27840, 28240, 28415, 28455, 33210, 37206, 37565, 55845, 57410, 61055, 61530, 64802, 64818, 66250, 67015, 69000, 69910, 86891, 86900, 88233, 92547, 95956, 15839, 20550, 23130, 23140, 23146, 23155, 24105, 25210, 25605, 26370, 26530, 27194, 27614, 28106, 28220, 28465, 28630, 29840, 29879, 31225, 32405, 33820, 33845, 35820, 36014, 37205, 38500, 42806, 42950, 57250, 61501, 61703, 62142, 62146, 11200, 11401, 11421, 11772, 20600, 20974, 21310, 21557, 23020, 23585, 27087, 27140, 27676, 28400, 28585, 29305, 30930, 38241, 43030, 43415, 88300, 15876, 17999, 20206, 20950, 30117, 37204, 61345, 61458, 11420, 15852, 20200, 20205, 20910, 41150, 51705, 61107, 62100, 69930, 27702, 55840, 20605, 27345, 29345, 22856, 22857, 22858, 22861, 22862, 22864, 22865, 27472, 32503, 32666, 35879, 43644, 44602, 47562, 49203, 49561, 49585, 49587, 49999, 58570, 32505, 32550, 32551, 32601, 32651, 43200, 43235, 43300, 43420, 44005, 44604, 45330, 49020, 49650, 49652, 49904, 61608, 61619, 61781, 0095T, 0098T
Cervical
22556, 22558, 22610, 22612, 22614, 22633, 22800, 22802, 22804, 22808, 22810, 22810, 22812, 22848, 22849
Lumbar
None
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22110, 27158, 29881, 37799, 60270, 20660, 26055, 31622, 35701, 41250, 63700, 20969, 49255, 33802, 20650, 24579, 29848, 61304, 19371, 35341, 10120, 28899, 62223, 31720, 21550, 23929, 32650,
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IMPACT OF DIALYSIS ON 30-DAY OUTCOMES AFTER SPINAL FUSION
Supplementary Table 2. All Excluded International Classification of Diseases, Ninth Revision, Clinical Modification and International Classification of Diseases, Tenth Revision, Clinical Modification Codes International Classification of Diseases, Ninth Revision, Clinical Modification
1985, 8054, 8052, 80502, 3241, 1983, 80506, 1702, 95203, 80505, 7217, 2253, 2254, 7200, 80507, 1984, 80501, 80500, 83905, 73008, 73018, 73200, 8064, 1922, 2392, 80605, 80508, 83920, 83906, 83908, 80504, 80503, 80600, 20300, 80625, 2132, 8058, 80608, 2375, 3492, 80603, 95200, 2159, 3249, 95205, 99859, 1719, 83904, 1923, 2386, 2380, 83903, 2397, 8056, 19889, 2157, 2158, 80500, 83901, 74782, 80500, 1991, 80604, 83900, 9051, 2148, 73319, 80609, 83921, 95200, 1709, 2259, 34400, 72691, 73381, 75552, 7802, 78079, 80606, 95204, 1706, 1929, 2252, 23771, 3361, 42731, 56731, 71538, 71598, 73312, 73322, 80624, 80629, 95209, 99644, 99663, 99709, 138, 1718, 185, 193, 20288, 72702, 72743, 72749, 73098, 73329, 73395, 78097, 7842, 83907, 95200, 95202, 99812, 99932, 1505, 1143, 1623, 1629, 1749, 1976, 19881, 20979, 2136, 2376, 2379, 2396, 23989, 2536, 27402, 34409, 3449, 3484, 34989, 3559, 4019, 4211, 431, 4353, 44024, 47824, 55221, 5531, 56211, 6224, 6828, 7135, 72612, 72888, 73000, 73000, 73088, 73711, 7402, 75617, 7674, 7812, 7907, 79092, 80514, 8053, 80601, 80628, 8069, 82021, 9072, 9522, 9528, E8781, V5417, V689, 1502, 1504, 3819, 1539, 1542, 1625, 1714, 1717, 1743, 1918, 1919, 1955, 1961, 1972, 1973, 19882, 2152, 2258, 226, 2281, 2298, 2373, 23773, 2389, 23981, 2411, 2419, 2449, 25022, 2572, 2724, 27489, 2749, 27651, 2809, 2851, 28521, 29181, 2967, 3383, 34402, 34404, 3535, 3551, 3561, 3569, 3962, 4011, 41071, 41401, 41519, 4241, 4275, 42833, 4321, 43491, 4359, 44021, 4564, 51851, 51889, 53909, 5409, 55091, 55321, 5559, 6111, 6121, 6183, 66564, 6822, 7092, 71616, 71918, 7235, 7282, 7285, 7311, 7324, 73314, 73315, 73316, 73342, 73733, 73742, 7383, 75551, 75613, 7564, 75651, 7724, 78031, 7854, 7962, 80602, 80607, 80619, 80621, 80627, 80635, 8065, 81342, 82002, 85202, 85221, 85226, 95201, 95206, 99662, V1052, V1081
International Classification of Diseases, Tenth Revision, Clinical Modification
A1781, A1789, A1801, C061, C3411, C3490, C412, C700, C701, C720, C729, C7900, C7931, C7949, C800, C801, G061, G062, G8254, M4200, M4202, M4204, M4205, M4212, M4216, M450, M452, M453, M454, M456, M457, M459, M4620, M4622, M4623, M4624, M4625, M4626, M4627, M4632, M4633, M4634, M4636, M4640, M4642, M4643, M4644, M4645, M4646, M4647, M4682, M4686, M4687, M4691, M4692, M4694, M4696, M4810, M4812, M4816, M4817, M4830, M4832, M4836, M4837, M4842XA, M4848XA, M4852XA, M4852XG, M4852XS, M4854XA, M4854XG, M4855XA, M4856XA, M4856XG, M4857XA, M4858XA, M8440XA, M8448XA, M8458XA, M8458XG, M8468XA, M8468XK, M8550, M8558, M86172, M8618, M8629, M8668, M868X8, M869, M889, M8938, Q762, Q763, Q76414, Q76415, Q7649, Q796, S065X1A, S066X0A, S12000A, S12000B, S12000K, S12001K, S1201XA, S1202XA, S1202XG, S12030A, S12040A, S12040K, S12090K, S12091A, S12100A, S12100G, S12100K, S12100S, S12101A, S12110A, S12110G, S12110K, S12111A, S12111G, S12111K, S12112A, S12112B, S12112K, S12120A, S12120G, S12120K, S12121A, S12121K, S1214XA, S12190A, S12190G, S12190K, S12200A, S12200S, S12290A, S12300A, S12300K, S12330A, S12390A, S12400A, S12400G, S12400K, S12401A, S12430A, S12430K, S1244XA, S12450A, S12490A, S12500A, S12500B, S12500K, S12500S, S12501A, S12530A, S12530G, S12590A, S12591A, S12600A, S12600G, S12600K, S12600S, S12601A, S12601S, S12630A, S12690A, S12690G, S128, S129XXA, S129XXD, S129XXS, S130XXA, S13100A, S13111A, S13120A, S13121A, S13140A, S13141A, S13150A, S13151A, S13151S, S13160A, S13160D, S13161A, S13161D, S13170A, S13171A, S13180A, S134XXA, S140XXA, S14101A, S14103A, S14104A, S14105A, S14106A, S14107A, S14109A, S14109S, S14113A, S14116A, S14121A, S14122A, S14123A, S14123S, S14124A, S14125A, S14126A, S14127A, S14129A, S14129D, S14133A, S14141D, S14152A, S14154A, S14155A, S21209A, S22000A, S22001S, S22008B, S22009A, S22009G, S22009S, S22010A, S22019A, S22029G, S22032A, S22039A, S22041A, S22050A, S22058A, S22059A, S22060A, S22061A, S22062A, S22068A, S22068D, S22069A, S22070A, S22071A, S22071K, S22078A, S22078G, S22080A, S22080D, S22080K, S22081A, S22081B, S22081S, S22082A, S22082B, S22082K, S22088A, S22089A, S22089D, S23111A, S23150A, S23161A, S23163A, S23171A, S24103A, S24104A, S24151A, S242XXS, S3200, S32000D, S32001A, S32001D, S32001K, S32009A, S32009K, S32009S, S32010A, S32010K, S32011A, S32011G, S32012A, S32018A, S32018K, S32019A, S32021A, S32022A, S32022K, S32028A, S32029A, S32030A, S32030G, S32031A, S32031K, S32032A, S32038A, S32039A, S32041A, S32042A, S32042K, S32048A, S32049A, S32050A, S32051A, S32058A, S32058K, S32059A, S32059K, S3210XA, S3215XA, S329XXA, S329XXK, S329XXS, S330XXA, S330XXD, S33100A, S33131A, S33141A, S3339XA, S3421XA, S42292A, S72001A, S72145A
Supplementary Table 3. Current Procedural Terminology Codes for Related Return to the Operating Room Lumbar
10180, 11042, 20680
Cervical
10140, 10180, 11043, 11044, 12020, 13160, 20680, 21501, 22010, 22551, 22600, 22830, 22840, 22849, 31600, 37600, 63045, 63081, 63740, 97597
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WORLD NEUROSURGERY, https://doi.org/10.1016/j.wneu.2019.07.021