- Email: [email protected]
Postoperative Surgical Site Infection After Spine Surgery: An Update From the Scoliosis Research Society (SRS) Morbidity and Mortality Database*
Spine Deformity 6 (2018) 634e643 www.spine-deformity.org
Case Series
Postoperative Surgical Site Infection After Spine Surgery: An Update From the Scoliosis Research Society (SRS) Morbidity and Mortality Database* Jamal N. Shillingford, MDa, Joseph L. Laratta, MDa,*, Hemant Reddy, BSa, Alex Ha, MDa, Ronald A. Lehman, Jr, MDb, Lawrence G. Lenke, MDa, Charla R. Fischer, MDa a
Department of Orthopaedic Surgery, Columbia University Medical Center, The Spine Hospital, New York-Presbyterian Healthcare System, 5141 Broadway, 3 Field West, New York, NY 10034, USA b The Daniel and Jane Och Spine Hospital, NewYork-Presbyterian/The Allen Hospital, 5141 Broadway, 3 Field West, New York, NY 10034, USA Received 5 October 2017; revised 11 March 2018; accepted 9 April 2018
Study Design: Retrospective review of prospectively collected data. Objective: Analyze the Scoliosis Research Society (SRS) Morbidity & Mortality (M&M) database to assess the incidence and characteristics related to postoperative surgical site infection (SSI) after spinal deformity surgery. Summary of Background Data: Infections involving spinal instrumentation are associated with greater rates of disability. Rates of postoperative SSI after spinal deformity surgery range from 1.9% to 4.4%. Postoperative SSI rates of 4.2% for adult kyphosis, 2.1% for adult spondylolisthesis, and 3.7% for adult scoliosis have been reported. Methods: The SRS M&M database was evaluated to define patient demographics, perioperative factors, and infection characteristics of spinal deformity patients with postoperative spine infections after deformity surgery in 2012. Results: Of the 47,755 procedures reported to the SRS in 2012, there were 578 (1.2%) diagnosed SSIs. Infection rates for patients with kyphosis were significantly higher compared with patients with scoliosis (2.4% vs. 1.1%, p ! .0001) or spondylolisthesis (2.4% vs. 1.1%, p ! .0001). Spinal fusions were performed in 86.3% of patients, 75.1% of which were performed posteriorly. Osteotomies were performed in 30.1% of patients. Deep infections below the fascia accounted for 68.0% of infections. Methicillin-sensitive (41.9%) and methicillin-resistant (17.0%) Staphylococcus aureus were the most commonly isolated pathogens, whereas gram-negative bacteria accounted for 25.4% of cases. Long-term antibiotic suppression was required in 18.9% of patients, and overall complications from antibiotics occurred in 4.5% of patients. Operative treatment was required in 81.8% of SSI cases. Conclusion: SSIs occur in 1.2% of spine deformity patients, with a rate significantly higher in patients with kyphosis. Approximately 25% of these infections are secondary to gram-negative species. Antibiotic complications occur in 4.5% of patients being treated for SSI. Despite advancements in surgical technique and infection prophylaxis, postoperative SSI remains one of the most common complications in spinal deformity surgery. Level of Evidence: Level III Ó 2018 Scoliosis Research Society. All rights reserved. Keywords: Spine; Surgical site infection; Scoliosis Research Society; Deformity; Kyphosis
Author disclosures: JNS (none), JLL (none), HR (none), AH (none), RAL (grants from PRORP [Department of Defense Peer Reviewed Orthopaedic Research Program]; personal fees and nonfinancial support from DePuy Synthes Spine, Stryker, and Medtronic, outside the submitted work), LGL (other [board membership fees] from OREF and GSO, personal fees [for consultancy] from DePuy Synthes Spine, K2M, and Medtronic, personal fees [for expert testimony] from Fox Rothschild, LLP; grants from AOSpine, Scoliosis Research Society, DePuy Synthes Spine, Setting Scoliosis Straight Foundation, and EOS; other [royalties from patents] from Medtronic; personal fees [travel accommodations/meeting expenses] from AOSpine, Broadwater, Seattle Science Foundation, Scoliosis Research Society, and The Spinal Research Foundation; fellowship grant [Evnor] from AOSpine,
North America; grants from [philanthropic research funding] Fox Family Foundation and Evans Family, outside the submitted work), CRF (none). This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors. IRB approval. The data within the SRS M&M database was de-identified and therefore deemed exempt by our institutional review board. *Corresponding author. Department of Orthopaedic Surgery, Columbia University Medical Center, The Spine Hospital, New York-Presbyterian Healthcare System, 5141 Broadway, 3 Field West, New York, NY 10034, USA. Tel.: (212) 305-4565; fax: (212) 305-6193. E-mail address: [email protected] (J.L. Laratta).
2212-134X/$ - see front matter Ó 2018 Scoliosis Research Society. All rights reserved. https://doi.org/10.1016/j.jspd.2018.04.004
J.N. Shillingford et al. / Spine Deformity 6 (2018) 634e643
635
Introduction
Materials and Methods
Surgical site infection (SSI) is a catastrophic and difficult complication to manage after spine surgery. Since the first description of tuberculosis manifestations in the spine hundreds of years ago, the morbidity of spine infections have been well documented in the medical literature [1]. According to the literature, infections involving spinal instrumentation are associated with even greater rates of disability [2]. Previous studies have implicated age O60 years, diabetes, increased body mass index, cigarette smoking, hypertension, alcohol abuse, procedure complexity, patient health status, traditional open approach, and prior SSI as risk factors for postoperative SSI [3-7]. Surgical databases, such as the Scoliosis Research Society (SRS) Morbidity and Mortality (M&M) database, have tremendous value in orthopedic surgery. SRS has gathered surgeon-reported complications, including instrumentation failure, visual disturbance, new neurologic deficits, death, and, most recently, infection. SRS members are required to submit data annually on all spine surgeries performed, as well as those associated with morbidity and mortality. Recently the amount of data gathered has increased massively [8]. Correspondingly, there have been numerous publications reporting on the data [9-13]. Unfortunately, many of the studies reporting on complications in spine surgery are limited by single surgeons, single institutions, or relatively small patient populations [14-17]. The true power of the SRS database is gained through its large and diverse sample size: extensive data collection, vast number of cases, broad spectrum of pathology, and extensive numbers of surgeons and institutions. Subsequent studies investigating complication rates between the SRS M&M database and longstanding complication databases have confirmed its validity in tracking postoperative outcomes [18]. With an aging population in the United States and an increasing amount of degenerative spinal conditions, there is an increased demand for surgical reconstructions, and correspondingly, an increased number of SSIs is expected. The risks for development of SSI after spine surgery warrants further investigation in order to appropriately inform patients preoperatively and address preventive measures [1922]. The purpose of this study was to analyze the SRS M&M database to assess the incidence and analyze characteristics related to postoperative SSI after spinal deformity surgery. The data garnered from a large, validated database, such as the SRS database, may allow for the development of generalizable conclusions about SSI in patients undergoing spinal deformity surgery.
Each year, members of the SRS are required to submit data on all spine surgeries performed, including those associated with morbidity and mortality. Deidentified data are collected through a secure web-based data entry form and attested for accuracy by the operating surgeon. If any SRS member chooses to forego the datareporting process, he or she is charged a monetary fee. Collected information includes the total number of surgeries performed across several diagnoses, death, acute infection, visual disturbance, and new neurologic deficit. The prospectively collected data submitted by 782 SRS members in the year 2012 was queried for all patients who experienced SSI as a complication. Patient demographics, medical comorbidities, preoperative diagnosis, intraoperative characteristics, and perioperative factors were analyzed. Intraoperative characteristics included operative time, operative blood loss, surgical approach, procedure type, osteotomies performed, procedure staging, type of antibiotic used for index surgery, timing of antibiotics before incision, and timing of postoperative antibiotic continuance. SSI-specific characteristics included timing of identification of infection, location of infection with respect to the fascia, bacteria cultured, antibiotic chosen for treatment, associated organ system infections, long-term antibiotic suppression, return to operation theater, number of irrigation and debridements, type of closure, surgical packing use, instrumentation removal and reinsertion, and complications from antibiotics. Basic descriptive statistics were reported and chisquare or Fisher exact tests were performed to determine differences between categorical data. A p value !.05 was considered statistically significant. Data were analyzed using SPSS Statistics v24.0 (IBM Corp, Armonk, NY). Results In 2012, of the 47,755 procedures reported to the SRS, there were 578 diagnosed SSIs, accounting for an infection rate of 1.2% (Table 1). The mean age for patients with SSI was 40.8 26.2, and 62.3% of patients were female. The most frequent comorbidities included hypertension (31.5%), pulmonary disorders (16.6%), and type 2 diabetes (13.7%). Data on American Society of Anesthesiologists (ASA) classification are reported in Table 1. Infection rates for patients with kyphosis were significantly higher compared with patients with scoliosis (2.4% vs. 1.1%, p ! .0001) or spondylolisthesis (2.4% vs. 1.1%, p ! .0001) (Table 1, Fig. 1). Spinal fusion was performed in 86.3% of patients, with the majority performed posteriorly (75.1%)
636
J.N. Shillingford et al. / Spine Deformity 6 (2018) 634e643
Table 1 Infection demographic data.
Table 2 Perioperative factors.
Demographics (N 5 578)
n (%) or mean SD
Surgical factors (N 5 578)
n (%) or mean SD
Age (yrs) Female Preoperative diagnosis Kyphosis Scoliosis Spondylolisthesis ASA classification 1: Normal healthy individual 2: Mild systemic disease 3: Severe systemic disease 4: Incapacitation systemic disease Comorbidities Type 1 diabetes Type 2 diabetes Smoker Hypertension Vascular disease Coronary artery disease Thromboembolic history Pulmonary history Cancer history
40.8 26.2 360 (62.3)
Fusion performed Staged procedure Operative blood loss, mL Osteotomy performed Osteotomy type Smith-Petersen Three-column osteotomy Fusion type Anterior fusion Posterior fusion Combined anterior/posterior fusion Operative times !2 hours 2e6 hours 6e9 hours 9e12 hours O12 hours Perioperative antibiotics for index surgery Cefazolin 1 g Cefazolin 2 g Cefazolin per weight Vancomycin 1 g Vancomycin per weight Vancomycin powder at surgical site Timing of antibiotics before incision !30 minutes 30e60 minutes O60 minutes Postoperative antibiotic continuance !24 hours 24e48 hours Until drains removed None of the above
499 (86.3) 49 (8.5) 918.9þ1356.2 174 (30.1)
112 (19.4) 294 (50.9) 169 (29.2) 127 184 218 35
(22.0) (31.8) (37.7) (6.1)
41 79 60 182 54 42 24 96 17
(7.1) (13.7) (10.4) (31.5) (9.3) (7.3) (4.2) (16.6) (2.9)
ASA, American Society of Anesthesiologists; SD, standard deviation.
(Table 2). Of the patients who had a postoperative SSI and fusion, 262 (52.5%) had sacrum extension and 233 (46.7%) did not have sacrum extension. Osteotomies were performed in 30.1% of patients, and 10.6% of all patients underwent a three-column osteotomy (Table 2). Postoperative infection occurred in 66.4% of patients with operative times lasting between 2 and 6 hours. Cefazolin was the most common perioperative antibiotic administered (83.1%), and intrawound vancomycin
110 (19.0) 61 (10.6) 4 (0.7) 434 (75.1) 59 (10.2) 56 384 96 29 3
(9.7) (66.4) (16.6) (5.0) (0.5)
183 219 78 59 32 59
(31.7) (37.9) (13.5) (10.2) (5.5) (10.2)
272 (47.1) 248 (42.9) 22 (3.8) 229 151 121 77
(39.6) (26.1) (20.9) (13.3)
SD, standard deviation.
Fig. 1. Infection complication rates were compared based on diagnosis. The rate of postoperative SSI varied based on the spinal pathology, with rates of 2.4% for kyphosis, 1.1% for spondylolisthesis, and 1.1% for scoliosis. Infection rates for patients with kyphosis were significantly higher compared with patients with scoliosis (2.4% vs. 1.1%, p ! .0001) or spondylolisthesis (2.4% vs. 1.1%, p ! .0001). SSI, surgical site infection.
J.N. Shillingford et al. / Spine Deformity 6 (2018) 634e643
637
Fig. 2. Perioperative antibiotic use among patients with surgical site infections was plotted against antibiotic regimen. Cefazolin was the most common antibiotic administered (83.1%). Cefazolin 1 g was given 31.7%, cefazolin 2 g was given 37.9%, and cefazolin per weight was given 13.5% of the time. Vancomycin 1 g was given 10.2%, vancomycin per weight was given 5.5%, and vancomycin powder at surgical site was given 10.2% of the time.
powder was applied at the index procedure in 10.2% of patients with postoperative infections (Table 2, Fig. 2). Among patients with SSI, 39.6% received postoperative antibiotics for 24 hours, 26.1% for 48 hours, and 20.9% until drains were removed (Table 2, Fig. 3).
SSIs were identified at an average of 18.4 16.2 days from the index procedure (Table 3). Deep infection, defined as those occurring below the fascia, accounted for 68.0% of infections (Table 3). Bacteria cultured from SSIs were stratified as gram positive only, gram negative only,
Fig. 3. The percentage of patients receiving postoperative antibiotic treatment for surgical site infection (SSI) was plotted against the duration of infection treatment. Among patients with SSI, 39.6% received postoperative antibiotics for 24 hours, 26.1% for 48 hours, and 20.9% of patients received antibiotics until drains were removed.
638
J.N. Shillingford et al. / Spine Deformity 6 (2018) 634e643
Table 3 Infection-specific characteristics. Infection specific characteristics (N 5 578) Time to infection Average days from surgery to infection Infection location Superficial (above fascia) Deep (below fascia) Bacteria cultured Gram-positive: methicillin-sensitive Staphylococcus aureus Gram-positive: methicillin-resistant S. aureus Gram-positive: Staphylococcus epidermidis Gram-negative: Escherichia coli Gram-negative: Proteus Gram-negative: Pseudomonas Gram-negative: not listed Polymicrobial: gram-positive and gram-negative Other: not listed Polymicrobial cultures: Gram-positive and gram-negative Gram-positive: methicillin-sensitive S. aureus Gram-positive: methicillin-resistant S. aureus Gram-positive: Staphylococcus epidermidis Gram-negative: E. coli Gram-negative: Proteus Gram-negative: Pseudomonas Gram-negative: not listed
n (%) or mean SD 18.4 16.2 158 (27.3) 393 (68.0) 222 (38.4) 88 41 38 9 21 42 37 80
(15.2) (7.1) (6.6) (1.6) (3.6) (7.3) (6.4) (13.8)
20 10 7 18 1 5 13
(54.1) (27.0) (18.9) (48.6) (2.7) (13.5) (35.1)
SD, standard deviation.
or polymicrobial, culturing both gram-positive and gramnegative organisms. Among gram-positive only SSI, methicillin-sensitive (MSSA) and methicillin resistant (MRSA) Staphylococcus aureus were the most commonly
isolated pathogens, cultured in 38.4% and 15.2% of SSIs, respectively (Table 3, Fig. 4). Polymicrobial cultures were found in 6.4% of SSI. Of the polymicrobial SSIs, 54.1% cultured MSSA and 48.6% cultured Escherichia coli (Table 3). Of all SSIs, including polymicrobial SSIs, 41.9% isolated MSSA, 17.0% isolated MRSA, and 25.4% contained gram-negative bacteria. Adult and pediatric spinal deformity were compared (Table 4). Between adult and pediatric patients with SSI, the highest SSI was seen in pediatric scoliosis (31.8%) followed by spondylolisthesis (29.6%). Of those with adult kyphosis, 45.2% of SSIs were due to MSSA versus 33.3% with adult scoliosis. Of those with adult scoliosis, 21.3% of SSIs were due to MRSA versus 6.8% with adult kyphosis. Of those with pediatric scoliosis, neuromuscular scoliosis accounted for 45.0% of SSIs followed by 33.3% with idiopathic scoliosis. Overall, gram-negative pediatric spine SSIs were 27.3%, with 6.8% being polymicrobial in nature. Gramnegative organisms accounted for 42.0% of neuromuscular scoliosis SSIs, with 9.9% being polymicrobial in nature (Table 4). Among patients with SSIs after perioperative cefazolin, 44.0% of SSIs were due to MSSA and 14.4% were due to MRSA. Among patients with SSIs after perioperative vancomycin, 16.0% of SSIs were due to MSSA and 29.3% were due to MRSA (Fig. 5). Vancomycin (29.1%) followed by cefazolin (13.5%) were the primary antibiotics used in the treatment of SSI (Table 5). The average duration of antibiotics for treating SSI was 29.1 days for intravenous (IV) administration and 70.8 days for oral therapy. The most commonly associated organ system infections were
Fig. 4. The causal infectious pathogens for surgical site infection were compared. Methicillin-sensitive (38.4%) and methicillin-resistant (15.2%) Staphylococcus aureus were the most commonly isolated pathogens in surgical site infection (SSI). Of all SSIs, including polymicrobial SSI, 25.4% contained gramnegative bacteria.
J.N. Shillingford et al. / Spine Deformity 6 (2018) 634e643
639
Table 4 A comparison of adult and pediatric spinal deformity. Adult and pediatric spinal deformity, N 5 570
Surgical site infection, n (%)
Methicillinsensitive Staphylococcus aureus, n (%)
Adult kyphosis 73 (12.8) 33 (45.2) (age O18 years) Adult scoliosis 108 (18.9) 36 (33.3) (age O18 years) Pediatric kyphosis 39 (6.8) 19 (48.7) (age !18 years) Pediatric scoliosis 181 (31.8) 80 (44.2) (age !18 years) Spondylolisthesis 169 (29.6) 51 (30.2) (any age years) Scoliosis, pediatric, N 5 181 Idiopathic 60 (33.3) 30 (50.0) scoliosis Congenital 16 (8.9) 10 (62.5) scoliosis Neuromuscular 81 (45.0) 28 (34.6) scoliosis
Methicillin- Staphylococcus Escherichia Proteus, Pseudomonas, resistant epidermidis, coli, n (%) n (%) n (%) S. aureus, n (%) n (%)
Other Polymicrobial, Other: gramn (%) not negative, listed, n n (%) (%)
5 (6.8)
9 (12.3)
4 (5.5)
2 (2.7)
3 (4.1)
3 (4.1)
5 (6.8)
9 (12.3)
23 (21.3)
8 (7.4)
4 (3.7)
2 (1.9)
4 (3.7)
10 (9.3)
8 (7.4)
13 (12.0)
3 (7.7)
2 (5.1)
2 (5.1)
0 (0.0)
2 (5.1)
2 (5.1)
5 (12.8)
19 (10.5)
9 (5.0)
15 (8.3)
3 (1.7)
6 (3.3)
13 (7.2)
13 (7.2)
23 (12.7)
37 (21.9)
13 (7.7)
13 (7.7)
2 (1.2)
6 (3.6)
11 (6.5)
9 (5.3)
27 (16.0)
5 (8.3)
5 (8.3)
0 (0.0)
0 (0.0)
3 (5.0)
4 (6.7)
2 (3.3)
11 (18.3)
4 (25.0)
1 (6.3)
1 (6.3)
0 (0.0)
0 (0.0)
0 (0.0)
0 (0.0)
0 (0.0)
9 (11.1)
1 (1.2)
12 (14.8)
3 (3.7)
3 (3.7)
8 (9.9)
8 (9.9)
9 (11.1)
lung (2.2%) and genitourinary (2.2%). Of the patients with associated lung infection, 61.5% occurred in scoliosis patients, with neuromuscular scoliosis (75.0%) being the most common type (Table 5). Long-term antibiotic suppression was required in 18.9% of patients, largely because of grampositive (57.0%) organisms, followed by gram-negative (17.2%) and polymicrobial infections (10.2%) (Table 6).
4 (10.3)
Complications from antibiotics occurred in 4.5% of patients, the most common of which were allergic reactions (0.7%), colitis/diarrhea (0.5%), and Clostridium difficile infection (0.5%). Other complications were fever/neutropenia (0.3%), pancytopenia (0.2%), acute renal failure (0.2%), acute kidney injury (0.2%), arthralgia (0.2%), drug reaction with eosinophilia and systemic symptoms
Fig. 5. Perioperative antibiotic use was plotted against bacteria cultured from a surgical site infection (SSI). Among those who received perioperative cefazolin, 44.0% of SSIs were due to methicillin-sensitive Staphylococcus aureus and 14.4% were due to methicillin-resistant S. aureus. Among those who received perioperative vancomycin, 16.0% of SSIs were due to methicillin-sensitive S. aureus and 29.3% were due to methicillin-resistant S. aureus.
640
J.N. Shillingford et al. / Spine Deformity 6 (2018) 634e643
Table 5 Primary antibiotic agent chosen for treatment, associated organ system infections, and stratification of genitourinary and lung infection by diagnosis (N 5 578). n (%) Primary antibiotic agent chosen Penicillin Cefazolin Vancomycin Cephalosporin (other) Aminoglycoside Combination agent Sulfonamide Fluoroquinolone Macrolide Tetracycline Carbapenem Anti-parasitic Other Average duration of antibiotic therapy for postoperative SSI, Intravenous antibiotic Oral antibiotic Associated organ system infection Central nervous system Lung Genitourinary Other Diagnosis of patients with genitourinary infection, n 5 13 Kyphosis Spondylolisthesis Scoliosis Diagnosis of patients with lung infection, n 5 13 Kyphosis Spondylolisthesis Scoliosis Type of scoliosis in patients with lung infection, n 5 8 Idiopathic Degenerative Neuromuscular
23 (4.0) 78 (13.5) 168 (29.1) 66 (11.4) 13 (2.2) 20 (3.5) 6 (1.0) 19 (3.3) 28 (4.8) 2 (0.3) 18 (3.1) 4 (0.7) 22 (3.8) days 29.1 70.8 1 13 13 14
(0.2) (2.2) (2.2) (2.4)
4 (30.8) 4 (30.8) 5 (38.5) 3 (23) 2 (15.4) 8 (61.5) 1 (12.5) 1 (12.5) 6 (75.0)
SSI, surgical site infection.
(DRESS) syndrome (0.2%), mouth ulcers (0.2%), red man syndrome (0.2%), PICC line infection (0.2%), neck line deep venous thrombosis (0.2%), and rhabdomyolysis from daptomycin (0.2%). Operative treatment was required in 81.8% of cases, with 5.5% of patients requiring four or more irrigation and debridements (Table 6). Of the patients requiring four or more irrigation and debridements, 21.9% was due to MRSA and 15.6% due to MSSA (Table 6). Of those patients who underwent operative irrigation and debridement, 72.3% had their incision primarily closed, whereas 21.8% underwent secondary closure. Closed system (ie, Vacpack) packing was used most frequently after the operative debridement for postoperative management (33.2%). Instrumentation was removed in 12.1% of patients who returned to the operation theater for irrigation and debridement. Of the patients who underwent instrumentation removal, 40.4% had instrumentation reinserted between 45 and 90 days after the index procedure.
Table 6 Operative and long-term treatments of surgical site infection. SSI treatment (N 5 578)
n (%)
Long-term antibiotic 109 (18.9) Return to operation theater 473 (81.8) Organisms requiring long-term antibiotics Gram-positive 73 (57.0) Gram-negative 22 (17.2) Polymicrobial: gram-positive 13 (10.2) and gram-negative Other: not listed 7 (5.5) Type of closure Primary 345 (59.7) Secondary 103 (17.8) Packing used Closed system (ie, Vacpack) 192 (33.2) Inflow-outflow irrigation 23 (4.0) system Open packing 11 (1.9) Antibiotic beads 17 (2.9) Instrumentation removed 57 (9.9) Instrumentation reinserted 23 (4.0) How long from surgery to reinstrumentation 45e90 days 50% SSI treatment, n 5 473 Return to operation theater for irrigation and debridement 0 105 (18.2) 1 282 (48.8) 2 106 (18.3) 3 46 (8.0) 4 10 (1.7) O4 22 (3.8) Organisms requiring >4 irrigation and debridement, n 5 32 5 (15.6) Gram-positive: methicillin-sensitive Staphylococcus aureus Gram-positive: 7 (21.9) methicillin-resistant S. aureus Gram-positive: 0 (0.0) Staphylococcus epidermidis Gram-negative: 4 (6.3) Escherichia coli Gram-negative: Proteus 3 (9.4) Gram-negative: 4 (12.5) Pseudomonas Gram-negative: other 4 (12.5) Polymicrobial: gram4 (12.5) positive and gramnegative Other: not listed 3 (9.4)
Discussion Using data obtained from the SRS M&M database, the current study investigated the presence of SSI complications after spine surgery. Postoperative SSI is a devastating complication, which requires a rigorous analysis of predisposing risk factors and potential prevention methods in the perioperative period. Our study reports the most updated benchmarks regarding the
J.N. Shillingford et al. / Spine Deformity 6 (2018) 634e643
incidence, perioperative factors, and treatment of SSI after spinal deformity surgery. We report an overall postoperative SSI rate of 1.2%, or 12 infections per 1,000 deformity patients, which is lower than the rates of 1.9% to 4.4% previously reported in the literature [2-7,23,24]. In the current analysis, the rate of postoperative SSI varied based on the spinal pathology, with rates of 2.4% for kyphosis, 1.1% for spondylolisthesis, and 1.1% for scoliosis. Smith and colleagues reviewed 108,419 procedures from 2004 to 2007 and reported an overall SSI rate of 2.1%, with 4.2% for adult kyphosis, 2.1% for adult spondylolisthesis, and 3.7% for adult scoliosis [7]. Similarly, we found that patients with kyphosis have a significantly higher rate of postoperative SSI in comparison to patients with scoliosis and spondylolisthesis. Our analysis found that the most frequent comorbidities in patients with postoperative SSI were hypertension (31.5, pulmonary disorders (16.6%) and type 2 diabetes (13.7%), which parallels the literature [3-5]. Gunne and colleagues showed that diabetes and obesity were significant independent risk factors for both deep and superficial SSIs [4]. Chahoud and colleagues reviewed SSIs after spine surgery, noting that the common presenting symptoms typically manifested two to four weeks and up to three months after the index procedure [3]. Our analysis found an average infection identification of 18.4 16.2 days from the index procedure. Previous studies have shown that the commonly isolated pathogen in SSIs is S. aureus, occurring in about 50% of cases, ranging from 12% to 65% [2,3,13,14]. In our study, S. aureus was isolated in 58.8% of patients. Recent studies have shown that gram-negative bacteria account for more than 30% of all spine SSIs, and as much as 50% in pediatric cases of spine SSI [25]. Croft and colleagues’ study of pediatric SSI reported a gram-negative rate of 55% and found that neuromuscular scoliosis was associated with SSI (odds ratio 5 20.8, p ! .0001) and hospital readmission (odds ratio 5 23.6, p 5 .0007) [25]. Similarly, Mackenzie and colleagues’ multicenter retrospective review of SSI in pediatric spine surgery found that neuromuscular scoliosis had the greatest SSI rate (9.2%). Additionally, they found that 46.5% of SSI cultured gram-negative organisms (95% CI, 35.5% to 57.5%), and 97% of those infections occurred in nonidiopathic scoliosis patients (95% CI, 90.8% to 100.0%). Both studies attributed the high rate of gram-negative infection to wound contamination by feces or urine postoperatively [25,26]. We report an overall gram-negative SSI rate of 25.4% and overall gramnegative pediatric spine SSI rate of 27.3%, with 6.8% being polymicrobial in nature. Additionally, gramnegative organisms accounted for 42.0% of neuromuscular scoliosis SSI, with 9.9% being polymicrobial in nature. It can be argued that preoperative antibiotics with adequate gram-negative coverage in addition to traditional gram-positive coverage with first-generation
641
cephalosporins may assist in reducing SSI. However, according to the America Society of Health-System Pharmacists Therapeutic Guidelines, second- and thirdgeneration cephalosporins are not better than firstgeneration agents at preventing SSI, despite the broader range of coverage [27]. If there is clinical indication for administering antibiotics with greater gram-negative coverage, IV clindamycin or vancomycin with cefazolin should be administered. If patients are beta lactam allergic, aztreonam, gentamicin, or a single-dose fluoroquinolone may be used [27]. Patients at high risk for gram-negative SSI that may benefit from broader prophylactic coverage include those with lower lumbar spine surgery, neuromuscular scoliosis, bladder or fecal incontinence, posterior approach, and intravenous drug use [3,28-30]. Interestingly, an in vivo rabbit study of tobramycin-sensitive E. coliecontaminated wounds found that all rabbits treated with tobramycin powder had zero bacterial growth when cultured compared with control rabbits that all cultured positively (p ! .0001) [31]. Further research into the risk factors for gram-negative SSI and potential prophylactic measures is still required. Ultimately, clinicians must weigh the use of broaderspectrum antibiotics against the selection of antibiotic resistant organisms, antibiotic complications, and patient risk factors. Intrawound antibiotic powders are inexpensive and allow localized application of antibiotics to reach higher tissue concentrations in comparison to IV-administered antibiotics. Our study found that only 10.2% of patients who had intrawound vancomycin powder developed postoperative SSI. Multiple meta-analyses have reported that intrawound local vancomycin powder application significantly decreases SSI and S. aureus SSI [32-34]. Hida and colleagues’ 2017 retrospective study of 174 patients found that intrawound vancomycin had zero cases of deep SSI after undergoing invasive spine surgery with instrumentation implantation and high risk of infection [35]. Sweet and colleagues’ retrospective study of 1,732 patients found 2.6% deep SSI with cephalexin and a 0.2% deep SSI with cephalexin plus vancomycin powder (p ! .0001) [36]. O’Neil and colleagues’ retrospective study of 110 patients found a 0% SSI rate with vancomycin powder versus control with standard prophylaxis (13%, p 5 .02) [37]. In patients with significant comorbidities or undergoing complex spine surgery that increase the risk of infection, the North American Spine Society recommends the application of intrawound vancomycin or gentamicin to decrease SSI in comparison to standard prophylaxis regimens [34]. Takemoto and colleagues’ prospective randomized trial of 314 patients found no significant difference in SSI between 24-hour perioperative antibiotic prophylaxis and antibiotics until drain removal (12.4% vs. 13.2%, p 5 .48) [38]. They concluded that continued perioperative antibiotics for the entire duration that a drain is in place after spinal surgery did not decrease the rate of SSI.
642
J.N. Shillingford et al. / Spine Deformity 6 (2018) 634e643
Contrastingly, our analysis found that of those who developed an SSI, more patients with 24-hour prophylaxis (39.6%) and 48-hour prophylaxis (26.1%) developed SSIs than those with antibiotics for drain duration (20.9%). In addition to discussing the possibility of developing a postoperative SSI, physicians must also inform patients about management of SSIs, which involve the likelihood of multiple visits to the operation theater, possible instrumentation removal, or long-term antibiotics to help eradicate the infection. In this study, multiple operative debridements were performed in 31.8% of patients, and instrumentation removal was required in 12.1% of patients who returned to the operation theater for irrigation and debridement. Long-term antibiotic suppression was required for 18.9% of patients, and we found an overall complication rate of 4.5% secondary to antibiotics used for treatment of SSI. Intravenous antibiotics are usually recommended for six to eight weeks for patients with resistant organisms such as MRSA [38]. Given the long duration and complications secondary to IV antibiotic treatment, the prognosis of SSI treatment should be explained thoroughly to the patients undergoing spinal deformity surgery. The presented data is generalizable as it represents complication data from the largest deformity patient cohort from modern, fellowship-trained surgeons operating within the current standard of care across multiple institutions. Through a reduction in regional, institutional, and demographic influences, our reported data have significant generalizability. There are several limitations in the current study, most of which are inherent to analyses of large patient databases and the accuracy of submitted data. The SRS M&M database is subject to recall bias as members may input all data once a year before the deadline. Although complications may be underreported by members as higher complication rates are found in other retrospective studies, prior efforts aimed at validating the SRS database have ultimately concluded that differences would remain across several databases as a result of varying methods of data collection [12,18,23,39]. Additionally, the database does not include information regarding the postoperative evaluation and workup of patients with infection complications. Information regarding patient evaluation, such as appropriate physical examination findings, laboratory studies, imaging studies, and neurologic or infectious disease consultations, would allow for the creation of postoperative complication protocols. Lastly, because infection data were not collected in previous years, the data for the current analysis were limited to the year of 2012. Analysis of 47,755 spinal deformity cases submitted by SRS members in 2012 showed an average SSI rate of 1.2%, corresponding to an incidence of 12.1 per 1000 patients. Patients with a diagnosis of kyphosis had significantly higher rates of SSI than those with scoliosis or spondylolisthesis. More than 25% of isolated pathogens were secondary to gram-negative species. Antibiotic complications
occurred in 4.5% of patients with SSI. Despite advancements in surgical technique and infection prophylaxis, postoperative SSI remains one of the most common complications in spinal deformity surgery. Future studies are necessary to further elucidate potentially modifiable preoperative risk factors and develop evidence-based treatment protocols for the management of postoperative SSI. Key points Surgical site infections (SSIs) occur in 1.2% of spine deformity patients, with a rate significantly higher in patients with kyphosis. The rate of postoperative SSI varied based on the spinal pathology, with rates of 2.4% for kyphosis, 1.1% for spondylolisthesis, and 1.1% for scoliosis. Approximately 25% of these infections are secondary to gram-negative species. Antibiotic complications occur in 4.5% of patients being treated for SSI. Despite advancements in surgical technique and infection prophylaxis, postoperative SSI remains one of the most common complications in spinal deformity surgery.
References [1] Holloway KL, Henneberg RJ, de Barros Lopes M, Henneberg M. Evolution of human tuberculosis: a systematic review and metaanalysis of paleopathological evidence. Homo 2011;62:402e58. [2] Levi ADO, Dickman CA, Sonntag VKH. Management of postoperative infections after spinal instrumentation. J Neurosurg 1997;86: 975e80. [3] Chahoud J, Kanafani Z, Kanj SS. Surgical site infections following spine surgery: eliminating the controversies in the diagnosis. Front Med 2014;1:7. [4] ter Gunne A, Cohen D. Incidence, prevalence, and analysis of risk factors for surgical site infection following adult spinal surgery. Spine (Phila Pa 1976) 2009;34:1422e8. [5] Wimmer C, Glutch H, Franzreb M, Ogon M. Predisposing factors for infection in spine surgerda survey of 850 spinal procedures. J Spinal Disord 1998;11:124e8. [6] Olsen MA, Mayfield J, Lauryssen C, et al. Risk factors for surgical site infection in spinal surgery. J Neurosurg Spine 2003;98: 149e55. [7] Smith JS, Shaffrey CI, Sansur CA, et al. Rates of infection after spine surgery based on 108,419 procedures. Neurosurgery 2009;65:409. [8] Shaffrey E, Smith JS, Lenke LG, et al. Defining rates and causes of mortality associated with spine surgery: comparison of 2 data collection approaches through the Scoliosis Research Society. Spine (Phila Pa 1976) 2014;39:579e86. [9] Hamilton DK, Smith JS, Sansur CA, et al. Rates of new neurological deficit associated with spine surgery based on 108,419 procedures: a report of the Scoliosis Research Society Morbidity and Mortality Committee. Spine (Phila Pa 1976) 2011;36:1218e28. [10] Sansur CA, Smith JS, Coe JD, et al. Scoliosis Research Society morbidity and mortality of adult scoliosis surgery. Spine (Phila Pa 1976) 2011;36:E593e7. [11] Smith JS, Shaffrey CI, Sansur CA, et al. Rates of infection after spine surgery based on 108,419 procedures: a report from the Scoliosis Research Society Morbidity and Mortality Committee. Spine (Phila Pa 1976) 2011;36:556e63.
J.N. Shillingford et al. / Spine Deformity 6 (2018) 634e643 [12] Coe JD, Arlet V, Donaldson W, et al. Complications in spinal fusion for adolescent idiopathic scoliosis in the new millennium. A report of the Scoliosis Research Society Morbidity and Mortality Committee. Spine (Phila Pa 1976) 2006;31:345e9. [13] MacEwen GD, Bunnell WP, Sriram K. Acute neurological complications in the treatment of scoliosis. A report of the Scoliosis Research Society. J Bone Joint Surg Am 1975;57:404e8. [14] Gum JL, Lenke LG, Bumpass D, et al. Does planned staging for posterior-only vertebral column resections in spinal deformity surgery increase perioperative complications? Spine Deform 2016;4:131e7. [15] Papadopoulos EC, Boachie-Adjei O, Hess WF, et al. Early outcomes and complications of posterior vertebral column resection. Spine J 2015;15:983e91. [16] Ayvaz M, Olgun ZD, Demirkiran HG, et al. Posterior all-pedicle screw instrumentation combined with multiple chevron and concave rib osteotomies in the treatment of adolescent congenital kyphoscoliosis. Spine J 2014;14:11e9. [17] Ghayem Hassankhani E, Omidi-Kashani F, Moradkhani S, et al. Comparison of clinical and radiologic outcome of adolescent idiopathic scoliosis treated with hybrid hook-screw instrumentation versus universal clamp system. Adv Med 2016;2016:7639727. [18] Webb ML, Lukasiewicz AM, Samuel AM, et al. Overall similar infection rates reported in the physician-reported Scoliosis Research Society database and the chart-abstracted American College of Surgeons National Surgical Quality Improvement Program Database. Spine (Phila Pa 1976) 2015;40:1431e5. [19] Deyo RA, Gray DT, Kreuter W, et al. United States trends in lumbar fusion surgery for degenerative conditions. Spine (Phila Pa 1976) 2005;30:1441e5; discussion 1446e7. [20] Oglesby M, Fineberg SJ, Patel AA, et al. Epidemiological trends in cervical spine surgery for degenerative diseases between 2002 and 2009. Spine (Phila Pa 1976) 2013;38:1226e32. [21] Rajaee SS, Bae HW, Kanim LEA, Delamarter RB. Spinal fusion in the United States. Spine (Phila Pa 1976) 2012;37:67e76. [22] Weinstein JN, Lurie JD, Olson PR, et al. United States’ trends and regional variations in lumbar spine surgery: 1992e2003. Spine (Phila Pa 1976) 2006;31:2707e14. [23] Fang A, Hu SS, Endres N, Bradford DS. Risk factors for infection after spinal surgery. Spine (Phila Pa 1976) 2005;30:1460e5. [24] Weinstein MA, McCabe JP, Cammisa FPJ. Postoperative spinal wound infection: a review of 2,391 consecutive index procedures. J Spinal Disord 2000;13:422e6. [25] Croft LD, Pottinger JM, Chiang H-Y, et al. Risk factors for surgical site infections after pediatric spine operations. Spine (Phila Pa 1976) 2015;40:E112e9.
643
[26] Mackenzie WG, Matsumoto H, Williams BA, et al. Surgical site infection following spinal instrumentation for scoliosis: a multicenter analysis of rates, risk factors and pathogens. J Bone Joint Surg Am 2013;95:800e6. [27] Bratzler DW, Dellinger EP, Olsen KM, et al. Clinical practice guidelines for antimicrobial prophylaxis in surgery. Am J Health Pharm Ther Guidel 2013;70:582e667. [28] Massie JB, Heller JG, Abitbol JJ, et al. Postoperative posterior spinal wound infections. Clin Orthop Relat Res 1992;284:99e108. [29] Nasto LA, Colangelo D, Rossi B, et al. Post-operative spondylodiscitis. Eur Rev Med Pharmacol Sci 2012;16:50e7. [30] McDermott H, Bolger C, Humphreys H. Postprocedural discitis of the vertebral spine: challenges in diagnosis, treatment and prevention. J Hosp Infect 2012;82:152e7. [31] Laratta JL, Shillingford JN, Hardy N, et al. Intrawound tobramycin powder eradicates surgical wound contamination: an in vivo rabbit study. Spine (Phila Pa 1976) 2017;42:1393e7. [32] Chiang HY, Herwaldt LA, Blevins AE, et al. Effectiveness of local vancomycin powder to decrease surgical site infections: a meta-analysis. Spine J 2014;14:397e407. [33] Xiong L, Pan Q, Jin G, et al. Topical intrawound application of vancomycin powder in addition to intravenous administration of antibiotics: a meta-analysis on the deep infection after spinal surgeries. Orthop Traumatol Surg Res 2014;100:785e9. [34] Shaffer WO, Baisden JL, Fernand R, Matz PG. North American Spine Society. An evidence-based clinical guideline for antibiotic prophylaxis in spine surgery. Spine J 2013;13:1387e92. [35] Hida T, Ando K, Kobayashi K, et al. Intrawound vancomycin powder as prophylaxis of surgical site infection after invasive spine surgery with a high risk of infection. Nagoya J Med Sci 2017;79: 545e50. [36] Sweet FA, Roh M, Sliva C. Intrawound application of vancomycin for prophylaxis in instrumented thoracolumbuar fusions: efficacy, drug levels and patient outcomes. Spine (Phila Pa 1976) 2011;36: 2084e8. [37] O’Neil KR, Smith JG, Abtahi AM, et al. Reduced surgical site infections in patients undergoing posterior spinal stabilization of traumatic injuries using vancomycin powder. Spine J 2011;11: 641e6. [38] Takemoto R, Lonner B, Andres T, et al. Appropriateness of twentyfour-hour antibiotic prophylaxis after spinal surgery in which a drain is utilized. J Bone Joint Surg 2015;97:979e86. [39] Sharma S, Wu C, Andersen T, et al. Prevalence of complications in neuromuscular scoliosis surgery: a literature meta-analysis from the past 15 years. Eur Spine J 2013;22:1230e49.
Case Series
Postoperative Surgical Site Infection After Spine Surgery: An Update From the Scoliosis Research Society (SRS) Morbidity and Mortality Database* Jamal N. Shillingford, MDa, Joseph L. Laratta, MDa,*, Hemant Reddy, BSa, Alex Ha, MDa, Ronald A. Lehman, Jr, MDb, Lawrence G. Lenke, MDa, Charla R. Fischer, MDa a
Department of Orthopaedic Surgery, Columbia University Medical Center, The Spine Hospital, New York-Presbyterian Healthcare System, 5141 Broadway, 3 Field West, New York, NY 10034, USA b The Daniel and Jane Och Spine Hospital, NewYork-Presbyterian/The Allen Hospital, 5141 Broadway, 3 Field West, New York, NY 10034, USA Received 5 October 2017; revised 11 March 2018; accepted 9 April 2018
Study Design: Retrospective review of prospectively collected data. Objective: Analyze the Scoliosis Research Society (SRS) Morbidity & Mortality (M&M) database to assess the incidence and characteristics related to postoperative surgical site infection (SSI) after spinal deformity surgery. Summary of Background Data: Infections involving spinal instrumentation are associated with greater rates of disability. Rates of postoperative SSI after spinal deformity surgery range from 1.9% to 4.4%. Postoperative SSI rates of 4.2% for adult kyphosis, 2.1% for adult spondylolisthesis, and 3.7% for adult scoliosis have been reported. Methods: The SRS M&M database was evaluated to define patient demographics, perioperative factors, and infection characteristics of spinal deformity patients with postoperative spine infections after deformity surgery in 2012. Results: Of the 47,755 procedures reported to the SRS in 2012, there were 578 (1.2%) diagnosed SSIs. Infection rates for patients with kyphosis were significantly higher compared with patients with scoliosis (2.4% vs. 1.1%, p ! .0001) or spondylolisthesis (2.4% vs. 1.1%, p ! .0001). Spinal fusions were performed in 86.3% of patients, 75.1% of which were performed posteriorly. Osteotomies were performed in 30.1% of patients. Deep infections below the fascia accounted for 68.0% of infections. Methicillin-sensitive (41.9%) and methicillin-resistant (17.0%) Staphylococcus aureus were the most commonly isolated pathogens, whereas gram-negative bacteria accounted for 25.4% of cases. Long-term antibiotic suppression was required in 18.9% of patients, and overall complications from antibiotics occurred in 4.5% of patients. Operative treatment was required in 81.8% of SSI cases. Conclusion: SSIs occur in 1.2% of spine deformity patients, with a rate significantly higher in patients with kyphosis. Approximately 25% of these infections are secondary to gram-negative species. Antibiotic complications occur in 4.5% of patients being treated for SSI. Despite advancements in surgical technique and infection prophylaxis, postoperative SSI remains one of the most common complications in spinal deformity surgery. Level of Evidence: Level III Ó 2018 Scoliosis Research Society. All rights reserved. Keywords: Spine; Surgical site infection; Scoliosis Research Society; Deformity; Kyphosis
Author disclosures: JNS (none), JLL (none), HR (none), AH (none), RAL (grants from PRORP [Department of Defense Peer Reviewed Orthopaedic Research Program]; personal fees and nonfinancial support from DePuy Synthes Spine, Stryker, and Medtronic, outside the submitted work), LGL (other [board membership fees] from OREF and GSO, personal fees [for consultancy] from DePuy Synthes Spine, K2M, and Medtronic, personal fees [for expert testimony] from Fox Rothschild, LLP; grants from AOSpine, Scoliosis Research Society, DePuy Synthes Spine, Setting Scoliosis Straight Foundation, and EOS; other [royalties from patents] from Medtronic; personal fees [travel accommodations/meeting expenses] from AOSpine, Broadwater, Seattle Science Foundation, Scoliosis Research Society, and The Spinal Research Foundation; fellowship grant [Evnor] from AOSpine,
North America; grants from [philanthropic research funding] Fox Family Foundation and Evans Family, outside the submitted work), CRF (none). This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors. IRB approval. The data within the SRS M&M database was de-identified and therefore deemed exempt by our institutional review board. *Corresponding author. Department of Orthopaedic Surgery, Columbia University Medical Center, The Spine Hospital, New York-Presbyterian Healthcare System, 5141 Broadway, 3 Field West, New York, NY 10034, USA. Tel.: (212) 305-4565; fax: (212) 305-6193. E-mail address: [email protected] (J.L. Laratta).
2212-134X/$ - see front matter Ó 2018 Scoliosis Research Society. All rights reserved. https://doi.org/10.1016/j.jspd.2018.04.004
J.N. Shillingford et al. / Spine Deformity 6 (2018) 634e643
635
Introduction
Materials and Methods
Surgical site infection (SSI) is a catastrophic and difficult complication to manage after spine surgery. Since the first description of tuberculosis manifestations in the spine hundreds of years ago, the morbidity of spine infections have been well documented in the medical literature [1]. According to the literature, infections involving spinal instrumentation are associated with even greater rates of disability [2]. Previous studies have implicated age O60 years, diabetes, increased body mass index, cigarette smoking, hypertension, alcohol abuse, procedure complexity, patient health status, traditional open approach, and prior SSI as risk factors for postoperative SSI [3-7]. Surgical databases, such as the Scoliosis Research Society (SRS) Morbidity and Mortality (M&M) database, have tremendous value in orthopedic surgery. SRS has gathered surgeon-reported complications, including instrumentation failure, visual disturbance, new neurologic deficits, death, and, most recently, infection. SRS members are required to submit data annually on all spine surgeries performed, as well as those associated with morbidity and mortality. Recently the amount of data gathered has increased massively [8]. Correspondingly, there have been numerous publications reporting on the data [9-13]. Unfortunately, many of the studies reporting on complications in spine surgery are limited by single surgeons, single institutions, or relatively small patient populations [14-17]. The true power of the SRS database is gained through its large and diverse sample size: extensive data collection, vast number of cases, broad spectrum of pathology, and extensive numbers of surgeons and institutions. Subsequent studies investigating complication rates between the SRS M&M database and longstanding complication databases have confirmed its validity in tracking postoperative outcomes [18]. With an aging population in the United States and an increasing amount of degenerative spinal conditions, there is an increased demand for surgical reconstructions, and correspondingly, an increased number of SSIs is expected. The risks for development of SSI after spine surgery warrants further investigation in order to appropriately inform patients preoperatively and address preventive measures [1922]. The purpose of this study was to analyze the SRS M&M database to assess the incidence and analyze characteristics related to postoperative SSI after spinal deformity surgery. The data garnered from a large, validated database, such as the SRS database, may allow for the development of generalizable conclusions about SSI in patients undergoing spinal deformity surgery.
Each year, members of the SRS are required to submit data on all spine surgeries performed, including those associated with morbidity and mortality. Deidentified data are collected through a secure web-based data entry form and attested for accuracy by the operating surgeon. If any SRS member chooses to forego the datareporting process, he or she is charged a monetary fee. Collected information includes the total number of surgeries performed across several diagnoses, death, acute infection, visual disturbance, and new neurologic deficit. The prospectively collected data submitted by 782 SRS members in the year 2012 was queried for all patients who experienced SSI as a complication. Patient demographics, medical comorbidities, preoperative diagnosis, intraoperative characteristics, and perioperative factors were analyzed. Intraoperative characteristics included operative time, operative blood loss, surgical approach, procedure type, osteotomies performed, procedure staging, type of antibiotic used for index surgery, timing of antibiotics before incision, and timing of postoperative antibiotic continuance. SSI-specific characteristics included timing of identification of infection, location of infection with respect to the fascia, bacteria cultured, antibiotic chosen for treatment, associated organ system infections, long-term antibiotic suppression, return to operation theater, number of irrigation and debridements, type of closure, surgical packing use, instrumentation removal and reinsertion, and complications from antibiotics. Basic descriptive statistics were reported and chisquare or Fisher exact tests were performed to determine differences between categorical data. A p value !.05 was considered statistically significant. Data were analyzed using SPSS Statistics v24.0 (IBM Corp, Armonk, NY). Results In 2012, of the 47,755 procedures reported to the SRS, there were 578 diagnosed SSIs, accounting for an infection rate of 1.2% (Table 1). The mean age for patients with SSI was 40.8 26.2, and 62.3% of patients were female. The most frequent comorbidities included hypertension (31.5%), pulmonary disorders (16.6%), and type 2 diabetes (13.7%). Data on American Society of Anesthesiologists (ASA) classification are reported in Table 1. Infection rates for patients with kyphosis were significantly higher compared with patients with scoliosis (2.4% vs. 1.1%, p ! .0001) or spondylolisthesis (2.4% vs. 1.1%, p ! .0001) (Table 1, Fig. 1). Spinal fusion was performed in 86.3% of patients, with the majority performed posteriorly (75.1%)
636
J.N. Shillingford et al. / Spine Deformity 6 (2018) 634e643
Table 1 Infection demographic data.
Table 2 Perioperative factors.
Demographics (N 5 578)
n (%) or mean SD
Surgical factors (N 5 578)
n (%) or mean SD
Age (yrs) Female Preoperative diagnosis Kyphosis Scoliosis Spondylolisthesis ASA classification 1: Normal healthy individual 2: Mild systemic disease 3: Severe systemic disease 4: Incapacitation systemic disease Comorbidities Type 1 diabetes Type 2 diabetes Smoker Hypertension Vascular disease Coronary artery disease Thromboembolic history Pulmonary history Cancer history
40.8 26.2 360 (62.3)
Fusion performed Staged procedure Operative blood loss, mL Osteotomy performed Osteotomy type Smith-Petersen Three-column osteotomy Fusion type Anterior fusion Posterior fusion Combined anterior/posterior fusion Operative times !2 hours 2e6 hours 6e9 hours 9e12 hours O12 hours Perioperative antibiotics for index surgery Cefazolin 1 g Cefazolin 2 g Cefazolin per weight Vancomycin 1 g Vancomycin per weight Vancomycin powder at surgical site Timing of antibiotics before incision !30 minutes 30e60 minutes O60 minutes Postoperative antibiotic continuance !24 hours 24e48 hours Until drains removed None of the above
499 (86.3) 49 (8.5) 918.9þ1356.2 174 (30.1)
112 (19.4) 294 (50.9) 169 (29.2) 127 184 218 35
(22.0) (31.8) (37.7) (6.1)
41 79 60 182 54 42 24 96 17
(7.1) (13.7) (10.4) (31.5) (9.3) (7.3) (4.2) (16.6) (2.9)
ASA, American Society of Anesthesiologists; SD, standard deviation.
(Table 2). Of the patients who had a postoperative SSI and fusion, 262 (52.5%) had sacrum extension and 233 (46.7%) did not have sacrum extension. Osteotomies were performed in 30.1% of patients, and 10.6% of all patients underwent a three-column osteotomy (Table 2). Postoperative infection occurred in 66.4% of patients with operative times lasting between 2 and 6 hours. Cefazolin was the most common perioperative antibiotic administered (83.1%), and intrawound vancomycin
110 (19.0) 61 (10.6) 4 (0.7) 434 (75.1) 59 (10.2) 56 384 96 29 3
(9.7) (66.4) (16.6) (5.0) (0.5)
183 219 78 59 32 59
(31.7) (37.9) (13.5) (10.2) (5.5) (10.2)
272 (47.1) 248 (42.9) 22 (3.8) 229 151 121 77
(39.6) (26.1) (20.9) (13.3)
SD, standard deviation.
Fig. 1. Infection complication rates were compared based on diagnosis. The rate of postoperative SSI varied based on the spinal pathology, with rates of 2.4% for kyphosis, 1.1% for spondylolisthesis, and 1.1% for scoliosis. Infection rates for patients with kyphosis were significantly higher compared with patients with scoliosis (2.4% vs. 1.1%, p ! .0001) or spondylolisthesis (2.4% vs. 1.1%, p ! .0001). SSI, surgical site infection.
J.N. Shillingford et al. / Spine Deformity 6 (2018) 634e643
637
Fig. 2. Perioperative antibiotic use among patients with surgical site infections was plotted against antibiotic regimen. Cefazolin was the most common antibiotic administered (83.1%). Cefazolin 1 g was given 31.7%, cefazolin 2 g was given 37.9%, and cefazolin per weight was given 13.5% of the time. Vancomycin 1 g was given 10.2%, vancomycin per weight was given 5.5%, and vancomycin powder at surgical site was given 10.2% of the time.
powder was applied at the index procedure in 10.2% of patients with postoperative infections (Table 2, Fig. 2). Among patients with SSI, 39.6% received postoperative antibiotics for 24 hours, 26.1% for 48 hours, and 20.9% until drains were removed (Table 2, Fig. 3).
SSIs were identified at an average of 18.4 16.2 days from the index procedure (Table 3). Deep infection, defined as those occurring below the fascia, accounted for 68.0% of infections (Table 3). Bacteria cultured from SSIs were stratified as gram positive only, gram negative only,
Fig. 3. The percentage of patients receiving postoperative antibiotic treatment for surgical site infection (SSI) was plotted against the duration of infection treatment. Among patients with SSI, 39.6% received postoperative antibiotics for 24 hours, 26.1% for 48 hours, and 20.9% of patients received antibiotics until drains were removed.
638
J.N. Shillingford et al. / Spine Deformity 6 (2018) 634e643
Table 3 Infection-specific characteristics. Infection specific characteristics (N 5 578) Time to infection Average days from surgery to infection Infection location Superficial (above fascia) Deep (below fascia) Bacteria cultured Gram-positive: methicillin-sensitive Staphylococcus aureus Gram-positive: methicillin-resistant S. aureus Gram-positive: Staphylococcus epidermidis Gram-negative: Escherichia coli Gram-negative: Proteus Gram-negative: Pseudomonas Gram-negative: not listed Polymicrobial: gram-positive and gram-negative Other: not listed Polymicrobial cultures: Gram-positive and gram-negative Gram-positive: methicillin-sensitive S. aureus Gram-positive: methicillin-resistant S. aureus Gram-positive: Staphylococcus epidermidis Gram-negative: E. coli Gram-negative: Proteus Gram-negative: Pseudomonas Gram-negative: not listed
n (%) or mean SD 18.4 16.2 158 (27.3) 393 (68.0) 222 (38.4) 88 41 38 9 21 42 37 80
(15.2) (7.1) (6.6) (1.6) (3.6) (7.3) (6.4) (13.8)
20 10 7 18 1 5 13
(54.1) (27.0) (18.9) (48.6) (2.7) (13.5) (35.1)
SD, standard deviation.
or polymicrobial, culturing both gram-positive and gramnegative organisms. Among gram-positive only SSI, methicillin-sensitive (MSSA) and methicillin resistant (MRSA) Staphylococcus aureus were the most commonly
isolated pathogens, cultured in 38.4% and 15.2% of SSIs, respectively (Table 3, Fig. 4). Polymicrobial cultures were found in 6.4% of SSI. Of the polymicrobial SSIs, 54.1% cultured MSSA and 48.6% cultured Escherichia coli (Table 3). Of all SSIs, including polymicrobial SSIs, 41.9% isolated MSSA, 17.0% isolated MRSA, and 25.4% contained gram-negative bacteria. Adult and pediatric spinal deformity were compared (Table 4). Between adult and pediatric patients with SSI, the highest SSI was seen in pediatric scoliosis (31.8%) followed by spondylolisthesis (29.6%). Of those with adult kyphosis, 45.2% of SSIs were due to MSSA versus 33.3% with adult scoliosis. Of those with adult scoliosis, 21.3% of SSIs were due to MRSA versus 6.8% with adult kyphosis. Of those with pediatric scoliosis, neuromuscular scoliosis accounted for 45.0% of SSIs followed by 33.3% with idiopathic scoliosis. Overall, gram-negative pediatric spine SSIs were 27.3%, with 6.8% being polymicrobial in nature. Gramnegative organisms accounted for 42.0% of neuromuscular scoliosis SSIs, with 9.9% being polymicrobial in nature (Table 4). Among patients with SSIs after perioperative cefazolin, 44.0% of SSIs were due to MSSA and 14.4% were due to MRSA. Among patients with SSIs after perioperative vancomycin, 16.0% of SSIs were due to MSSA and 29.3% were due to MRSA (Fig. 5). Vancomycin (29.1%) followed by cefazolin (13.5%) were the primary antibiotics used in the treatment of SSI (Table 5). The average duration of antibiotics for treating SSI was 29.1 days for intravenous (IV) administration and 70.8 days for oral therapy. The most commonly associated organ system infections were
Fig. 4. The causal infectious pathogens for surgical site infection were compared. Methicillin-sensitive (38.4%) and methicillin-resistant (15.2%) Staphylococcus aureus were the most commonly isolated pathogens in surgical site infection (SSI). Of all SSIs, including polymicrobial SSI, 25.4% contained gramnegative bacteria.
J.N. Shillingford et al. / Spine Deformity 6 (2018) 634e643
639
Table 4 A comparison of adult and pediatric spinal deformity. Adult and pediatric spinal deformity, N 5 570
Surgical site infection, n (%)
Methicillinsensitive Staphylococcus aureus, n (%)
Adult kyphosis 73 (12.8) 33 (45.2) (age O18 years) Adult scoliosis 108 (18.9) 36 (33.3) (age O18 years) Pediatric kyphosis 39 (6.8) 19 (48.7) (age !18 years) Pediatric scoliosis 181 (31.8) 80 (44.2) (age !18 years) Spondylolisthesis 169 (29.6) 51 (30.2) (any age years) Scoliosis, pediatric, N 5 181 Idiopathic 60 (33.3) 30 (50.0) scoliosis Congenital 16 (8.9) 10 (62.5) scoliosis Neuromuscular 81 (45.0) 28 (34.6) scoliosis
Methicillin- Staphylococcus Escherichia Proteus, Pseudomonas, resistant epidermidis, coli, n (%) n (%) n (%) S. aureus, n (%) n (%)
Other Polymicrobial, Other: gramn (%) not negative, listed, n n (%) (%)
5 (6.8)
9 (12.3)
4 (5.5)
2 (2.7)
3 (4.1)
3 (4.1)
5 (6.8)
9 (12.3)
23 (21.3)
8 (7.4)
4 (3.7)
2 (1.9)
4 (3.7)
10 (9.3)
8 (7.4)
13 (12.0)
3 (7.7)
2 (5.1)
2 (5.1)
0 (0.0)
2 (5.1)
2 (5.1)
5 (12.8)
19 (10.5)
9 (5.0)
15 (8.3)
3 (1.7)
6 (3.3)
13 (7.2)
13 (7.2)
23 (12.7)
37 (21.9)
13 (7.7)
13 (7.7)
2 (1.2)
6 (3.6)
11 (6.5)
9 (5.3)
27 (16.0)
5 (8.3)
5 (8.3)
0 (0.0)
0 (0.0)
3 (5.0)
4 (6.7)
2 (3.3)
11 (18.3)
4 (25.0)
1 (6.3)
1 (6.3)
0 (0.0)
0 (0.0)
0 (0.0)
0 (0.0)
0 (0.0)
9 (11.1)
1 (1.2)
12 (14.8)
3 (3.7)
3 (3.7)
8 (9.9)
8 (9.9)
9 (11.1)
lung (2.2%) and genitourinary (2.2%). Of the patients with associated lung infection, 61.5% occurred in scoliosis patients, with neuromuscular scoliosis (75.0%) being the most common type (Table 5). Long-term antibiotic suppression was required in 18.9% of patients, largely because of grampositive (57.0%) organisms, followed by gram-negative (17.2%) and polymicrobial infections (10.2%) (Table 6).
4 (10.3)
Complications from antibiotics occurred in 4.5% of patients, the most common of which were allergic reactions (0.7%), colitis/diarrhea (0.5%), and Clostridium difficile infection (0.5%). Other complications were fever/neutropenia (0.3%), pancytopenia (0.2%), acute renal failure (0.2%), acute kidney injury (0.2%), arthralgia (0.2%), drug reaction with eosinophilia and systemic symptoms
Fig. 5. Perioperative antibiotic use was plotted against bacteria cultured from a surgical site infection (SSI). Among those who received perioperative cefazolin, 44.0% of SSIs were due to methicillin-sensitive Staphylococcus aureus and 14.4% were due to methicillin-resistant S. aureus. Among those who received perioperative vancomycin, 16.0% of SSIs were due to methicillin-sensitive S. aureus and 29.3% were due to methicillin-resistant S. aureus.
640
J.N. Shillingford et al. / Spine Deformity 6 (2018) 634e643
Table 5 Primary antibiotic agent chosen for treatment, associated organ system infections, and stratification of genitourinary and lung infection by diagnosis (N 5 578). n (%) Primary antibiotic agent chosen Penicillin Cefazolin Vancomycin Cephalosporin (other) Aminoglycoside Combination agent Sulfonamide Fluoroquinolone Macrolide Tetracycline Carbapenem Anti-parasitic Other Average duration of antibiotic therapy for postoperative SSI, Intravenous antibiotic Oral antibiotic Associated organ system infection Central nervous system Lung Genitourinary Other Diagnosis of patients with genitourinary infection, n 5 13 Kyphosis Spondylolisthesis Scoliosis Diagnosis of patients with lung infection, n 5 13 Kyphosis Spondylolisthesis Scoliosis Type of scoliosis in patients with lung infection, n 5 8 Idiopathic Degenerative Neuromuscular
23 (4.0) 78 (13.5) 168 (29.1) 66 (11.4) 13 (2.2) 20 (3.5) 6 (1.0) 19 (3.3) 28 (4.8) 2 (0.3) 18 (3.1) 4 (0.7) 22 (3.8) days 29.1 70.8 1 13 13 14
(0.2) (2.2) (2.2) (2.4)
4 (30.8) 4 (30.8) 5 (38.5) 3 (23) 2 (15.4) 8 (61.5) 1 (12.5) 1 (12.5) 6 (75.0)
SSI, surgical site infection.
(DRESS) syndrome (0.2%), mouth ulcers (0.2%), red man syndrome (0.2%), PICC line infection (0.2%), neck line deep venous thrombosis (0.2%), and rhabdomyolysis from daptomycin (0.2%). Operative treatment was required in 81.8% of cases, with 5.5% of patients requiring four or more irrigation and debridements (Table 6). Of the patients requiring four or more irrigation and debridements, 21.9% was due to MRSA and 15.6% due to MSSA (Table 6). Of those patients who underwent operative irrigation and debridement, 72.3% had their incision primarily closed, whereas 21.8% underwent secondary closure. Closed system (ie, Vacpack) packing was used most frequently after the operative debridement for postoperative management (33.2%). Instrumentation was removed in 12.1% of patients who returned to the operation theater for irrigation and debridement. Of the patients who underwent instrumentation removal, 40.4% had instrumentation reinserted between 45 and 90 days after the index procedure.
Table 6 Operative and long-term treatments of surgical site infection. SSI treatment (N 5 578)
n (%)
Long-term antibiotic 109 (18.9) Return to operation theater 473 (81.8) Organisms requiring long-term antibiotics Gram-positive 73 (57.0) Gram-negative 22 (17.2) Polymicrobial: gram-positive 13 (10.2) and gram-negative Other: not listed 7 (5.5) Type of closure Primary 345 (59.7) Secondary 103 (17.8) Packing used Closed system (ie, Vacpack) 192 (33.2) Inflow-outflow irrigation 23 (4.0) system Open packing 11 (1.9) Antibiotic beads 17 (2.9) Instrumentation removed 57 (9.9) Instrumentation reinserted 23 (4.0) How long from surgery to reinstrumentation 45e90 days 50% SSI treatment, n 5 473 Return to operation theater for irrigation and debridement 0 105 (18.2) 1 282 (48.8) 2 106 (18.3) 3 46 (8.0) 4 10 (1.7) O4 22 (3.8) Organisms requiring >4 irrigation and debridement, n 5 32 5 (15.6) Gram-positive: methicillin-sensitive Staphylococcus aureus Gram-positive: 7 (21.9) methicillin-resistant S. aureus Gram-positive: 0 (0.0) Staphylococcus epidermidis Gram-negative: 4 (6.3) Escherichia coli Gram-negative: Proteus 3 (9.4) Gram-negative: 4 (12.5) Pseudomonas Gram-negative: other 4 (12.5) Polymicrobial: gram4 (12.5) positive and gramnegative Other: not listed 3 (9.4)
Discussion Using data obtained from the SRS M&M database, the current study investigated the presence of SSI complications after spine surgery. Postoperative SSI is a devastating complication, which requires a rigorous analysis of predisposing risk factors and potential prevention methods in the perioperative period. Our study reports the most updated benchmarks regarding the
J.N. Shillingford et al. / Spine Deformity 6 (2018) 634e643
incidence, perioperative factors, and treatment of SSI after spinal deformity surgery. We report an overall postoperative SSI rate of 1.2%, or 12 infections per 1,000 deformity patients, which is lower than the rates of 1.9% to 4.4% previously reported in the literature [2-7,23,24]. In the current analysis, the rate of postoperative SSI varied based on the spinal pathology, with rates of 2.4% for kyphosis, 1.1% for spondylolisthesis, and 1.1% for scoliosis. Smith and colleagues reviewed 108,419 procedures from 2004 to 2007 and reported an overall SSI rate of 2.1%, with 4.2% for adult kyphosis, 2.1% for adult spondylolisthesis, and 3.7% for adult scoliosis [7]. Similarly, we found that patients with kyphosis have a significantly higher rate of postoperative SSI in comparison to patients with scoliosis and spondylolisthesis. Our analysis found that the most frequent comorbidities in patients with postoperative SSI were hypertension (31.5, pulmonary disorders (16.6%) and type 2 diabetes (13.7%), which parallels the literature [3-5]. Gunne and colleagues showed that diabetes and obesity were significant independent risk factors for both deep and superficial SSIs [4]. Chahoud and colleagues reviewed SSIs after spine surgery, noting that the common presenting symptoms typically manifested two to four weeks and up to three months after the index procedure [3]. Our analysis found an average infection identification of 18.4 16.2 days from the index procedure. Previous studies have shown that the commonly isolated pathogen in SSIs is S. aureus, occurring in about 50% of cases, ranging from 12% to 65% [2,3,13,14]. In our study, S. aureus was isolated in 58.8% of patients. Recent studies have shown that gram-negative bacteria account for more than 30% of all spine SSIs, and as much as 50% in pediatric cases of spine SSI [25]. Croft and colleagues’ study of pediatric SSI reported a gram-negative rate of 55% and found that neuromuscular scoliosis was associated with SSI (odds ratio 5 20.8, p ! .0001) and hospital readmission (odds ratio 5 23.6, p 5 .0007) [25]. Similarly, Mackenzie and colleagues’ multicenter retrospective review of SSI in pediatric spine surgery found that neuromuscular scoliosis had the greatest SSI rate (9.2%). Additionally, they found that 46.5% of SSI cultured gram-negative organisms (95% CI, 35.5% to 57.5%), and 97% of those infections occurred in nonidiopathic scoliosis patients (95% CI, 90.8% to 100.0%). Both studies attributed the high rate of gram-negative infection to wound contamination by feces or urine postoperatively [25,26]. We report an overall gram-negative SSI rate of 25.4% and overall gramnegative pediatric spine SSI rate of 27.3%, with 6.8% being polymicrobial in nature. Additionally, gramnegative organisms accounted for 42.0% of neuromuscular scoliosis SSI, with 9.9% being polymicrobial in nature. It can be argued that preoperative antibiotics with adequate gram-negative coverage in addition to traditional gram-positive coverage with first-generation
641
cephalosporins may assist in reducing SSI. However, according to the America Society of Health-System Pharmacists Therapeutic Guidelines, second- and thirdgeneration cephalosporins are not better than firstgeneration agents at preventing SSI, despite the broader range of coverage [27]. If there is clinical indication for administering antibiotics with greater gram-negative coverage, IV clindamycin or vancomycin with cefazolin should be administered. If patients are beta lactam allergic, aztreonam, gentamicin, or a single-dose fluoroquinolone may be used [27]. Patients at high risk for gram-negative SSI that may benefit from broader prophylactic coverage include those with lower lumbar spine surgery, neuromuscular scoliosis, bladder or fecal incontinence, posterior approach, and intravenous drug use [3,28-30]. Interestingly, an in vivo rabbit study of tobramycin-sensitive E. coliecontaminated wounds found that all rabbits treated with tobramycin powder had zero bacterial growth when cultured compared with control rabbits that all cultured positively (p ! .0001) [31]. Further research into the risk factors for gram-negative SSI and potential prophylactic measures is still required. Ultimately, clinicians must weigh the use of broaderspectrum antibiotics against the selection of antibiotic resistant organisms, antibiotic complications, and patient risk factors. Intrawound antibiotic powders are inexpensive and allow localized application of antibiotics to reach higher tissue concentrations in comparison to IV-administered antibiotics. Our study found that only 10.2% of patients who had intrawound vancomycin powder developed postoperative SSI. Multiple meta-analyses have reported that intrawound local vancomycin powder application significantly decreases SSI and S. aureus SSI [32-34]. Hida and colleagues’ 2017 retrospective study of 174 patients found that intrawound vancomycin had zero cases of deep SSI after undergoing invasive spine surgery with instrumentation implantation and high risk of infection [35]. Sweet and colleagues’ retrospective study of 1,732 patients found 2.6% deep SSI with cephalexin and a 0.2% deep SSI with cephalexin plus vancomycin powder (p ! .0001) [36]. O’Neil and colleagues’ retrospective study of 110 patients found a 0% SSI rate with vancomycin powder versus control with standard prophylaxis (13%, p 5 .02) [37]. In patients with significant comorbidities or undergoing complex spine surgery that increase the risk of infection, the North American Spine Society recommends the application of intrawound vancomycin or gentamicin to decrease SSI in comparison to standard prophylaxis regimens [34]. Takemoto and colleagues’ prospective randomized trial of 314 patients found no significant difference in SSI between 24-hour perioperative antibiotic prophylaxis and antibiotics until drain removal (12.4% vs. 13.2%, p 5 .48) [38]. They concluded that continued perioperative antibiotics for the entire duration that a drain is in place after spinal surgery did not decrease the rate of SSI.
642
J.N. Shillingford et al. / Spine Deformity 6 (2018) 634e643
Contrastingly, our analysis found that of those who developed an SSI, more patients with 24-hour prophylaxis (39.6%) and 48-hour prophylaxis (26.1%) developed SSIs than those with antibiotics for drain duration (20.9%). In addition to discussing the possibility of developing a postoperative SSI, physicians must also inform patients about management of SSIs, which involve the likelihood of multiple visits to the operation theater, possible instrumentation removal, or long-term antibiotics to help eradicate the infection. In this study, multiple operative debridements were performed in 31.8% of patients, and instrumentation removal was required in 12.1% of patients who returned to the operation theater for irrigation and debridement. Long-term antibiotic suppression was required for 18.9% of patients, and we found an overall complication rate of 4.5% secondary to antibiotics used for treatment of SSI. Intravenous antibiotics are usually recommended for six to eight weeks for patients with resistant organisms such as MRSA [38]. Given the long duration and complications secondary to IV antibiotic treatment, the prognosis of SSI treatment should be explained thoroughly to the patients undergoing spinal deformity surgery. The presented data is generalizable as it represents complication data from the largest deformity patient cohort from modern, fellowship-trained surgeons operating within the current standard of care across multiple institutions. Through a reduction in regional, institutional, and demographic influences, our reported data have significant generalizability. There are several limitations in the current study, most of which are inherent to analyses of large patient databases and the accuracy of submitted data. The SRS M&M database is subject to recall bias as members may input all data once a year before the deadline. Although complications may be underreported by members as higher complication rates are found in other retrospective studies, prior efforts aimed at validating the SRS database have ultimately concluded that differences would remain across several databases as a result of varying methods of data collection [12,18,23,39]. Additionally, the database does not include information regarding the postoperative evaluation and workup of patients with infection complications. Information regarding patient evaluation, such as appropriate physical examination findings, laboratory studies, imaging studies, and neurologic or infectious disease consultations, would allow for the creation of postoperative complication protocols. Lastly, because infection data were not collected in previous years, the data for the current analysis were limited to the year of 2012. Analysis of 47,755 spinal deformity cases submitted by SRS members in 2012 showed an average SSI rate of 1.2%, corresponding to an incidence of 12.1 per 1000 patients. Patients with a diagnosis of kyphosis had significantly higher rates of SSI than those with scoliosis or spondylolisthesis. More than 25% of isolated pathogens were secondary to gram-negative species. Antibiotic complications
occurred in 4.5% of patients with SSI. Despite advancements in surgical technique and infection prophylaxis, postoperative SSI remains one of the most common complications in spinal deformity surgery. Future studies are necessary to further elucidate potentially modifiable preoperative risk factors and develop evidence-based treatment protocols for the management of postoperative SSI. Key points Surgical site infections (SSIs) occur in 1.2% of spine deformity patients, with a rate significantly higher in patients with kyphosis. The rate of postoperative SSI varied based on the spinal pathology, with rates of 2.4% for kyphosis, 1.1% for spondylolisthesis, and 1.1% for scoliosis. Approximately 25% of these infections are secondary to gram-negative species. Antibiotic complications occur in 4.5% of patients being treated for SSI. Despite advancements in surgical technique and infection prophylaxis, postoperative SSI remains one of the most common complications in spinal deformity surgery.
References [1] Holloway KL, Henneberg RJ, de Barros Lopes M, Henneberg M. Evolution of human tuberculosis: a systematic review and metaanalysis of paleopathological evidence. Homo 2011;62:402e58. [2] Levi ADO, Dickman CA, Sonntag VKH. Management of postoperative infections after spinal instrumentation. J Neurosurg 1997;86: 975e80. [3] Chahoud J, Kanafani Z, Kanj SS. Surgical site infections following spine surgery: eliminating the controversies in the diagnosis. Front Med 2014;1:7. [4] ter Gunne A, Cohen D. Incidence, prevalence, and analysis of risk factors for surgical site infection following adult spinal surgery. Spine (Phila Pa 1976) 2009;34:1422e8. [5] Wimmer C, Glutch H, Franzreb M, Ogon M. Predisposing factors for infection in spine surgerda survey of 850 spinal procedures. J Spinal Disord 1998;11:124e8. [6] Olsen MA, Mayfield J, Lauryssen C, et al. Risk factors for surgical site infection in spinal surgery. J Neurosurg Spine 2003;98: 149e55. [7] Smith JS, Shaffrey CI, Sansur CA, et al. Rates of infection after spine surgery based on 108,419 procedures. Neurosurgery 2009;65:409. [8] Shaffrey E, Smith JS, Lenke LG, et al. Defining rates and causes of mortality associated with spine surgery: comparison of 2 data collection approaches through the Scoliosis Research Society. Spine (Phila Pa 1976) 2014;39:579e86. [9] Hamilton DK, Smith JS, Sansur CA, et al. Rates of new neurological deficit associated with spine surgery based on 108,419 procedures: a report of the Scoliosis Research Society Morbidity and Mortality Committee. Spine (Phila Pa 1976) 2011;36:1218e28. [10] Sansur CA, Smith JS, Coe JD, et al. Scoliosis Research Society morbidity and mortality of adult scoliosis surgery. Spine (Phila Pa 1976) 2011;36:E593e7. [11] Smith JS, Shaffrey CI, Sansur CA, et al. Rates of infection after spine surgery based on 108,419 procedures: a report from the Scoliosis Research Society Morbidity and Mortality Committee. Spine (Phila Pa 1976) 2011;36:556e63.
J.N. Shillingford et al. / Spine Deformity 6 (2018) 634e643 [12] Coe JD, Arlet V, Donaldson W, et al. Complications in spinal fusion for adolescent idiopathic scoliosis in the new millennium. A report of the Scoliosis Research Society Morbidity and Mortality Committee. Spine (Phila Pa 1976) 2006;31:345e9. [13] MacEwen GD, Bunnell WP, Sriram K. Acute neurological complications in the treatment of scoliosis. A report of the Scoliosis Research Society. J Bone Joint Surg Am 1975;57:404e8. [14] Gum JL, Lenke LG, Bumpass D, et al. Does planned staging for posterior-only vertebral column resections in spinal deformity surgery increase perioperative complications? Spine Deform 2016;4:131e7. [15] Papadopoulos EC, Boachie-Adjei O, Hess WF, et al. Early outcomes and complications of posterior vertebral column resection. Spine J 2015;15:983e91. [16] Ayvaz M, Olgun ZD, Demirkiran HG, et al. Posterior all-pedicle screw instrumentation combined with multiple chevron and concave rib osteotomies in the treatment of adolescent congenital kyphoscoliosis. Spine J 2014;14:11e9. [17] Ghayem Hassankhani E, Omidi-Kashani F, Moradkhani S, et al. Comparison of clinical and radiologic outcome of adolescent idiopathic scoliosis treated with hybrid hook-screw instrumentation versus universal clamp system. Adv Med 2016;2016:7639727. [18] Webb ML, Lukasiewicz AM, Samuel AM, et al. Overall similar infection rates reported in the physician-reported Scoliosis Research Society database and the chart-abstracted American College of Surgeons National Surgical Quality Improvement Program Database. Spine (Phila Pa 1976) 2015;40:1431e5. [19] Deyo RA, Gray DT, Kreuter W, et al. United States trends in lumbar fusion surgery for degenerative conditions. Spine (Phila Pa 1976) 2005;30:1441e5; discussion 1446e7. [20] Oglesby M, Fineberg SJ, Patel AA, et al. Epidemiological trends in cervical spine surgery for degenerative diseases between 2002 and 2009. Spine (Phila Pa 1976) 2013;38:1226e32. [21] Rajaee SS, Bae HW, Kanim LEA, Delamarter RB. Spinal fusion in the United States. Spine (Phila Pa 1976) 2012;37:67e76. [22] Weinstein JN, Lurie JD, Olson PR, et al. United States’ trends and regional variations in lumbar spine surgery: 1992e2003. Spine (Phila Pa 1976) 2006;31:2707e14. [23] Fang A, Hu SS, Endres N, Bradford DS. Risk factors for infection after spinal surgery. Spine (Phila Pa 1976) 2005;30:1460e5. [24] Weinstein MA, McCabe JP, Cammisa FPJ. Postoperative spinal wound infection: a review of 2,391 consecutive index procedures. J Spinal Disord 2000;13:422e6. [25] Croft LD, Pottinger JM, Chiang H-Y, et al. Risk factors for surgical site infections after pediatric spine operations. Spine (Phila Pa 1976) 2015;40:E112e9.
643
[26] Mackenzie WG, Matsumoto H, Williams BA, et al. Surgical site infection following spinal instrumentation for scoliosis: a multicenter analysis of rates, risk factors and pathogens. J Bone Joint Surg Am 2013;95:800e6. [27] Bratzler DW, Dellinger EP, Olsen KM, et al. Clinical practice guidelines for antimicrobial prophylaxis in surgery. Am J Health Pharm Ther Guidel 2013;70:582e667. [28] Massie JB, Heller JG, Abitbol JJ, et al. Postoperative posterior spinal wound infections. Clin Orthop Relat Res 1992;284:99e108. [29] Nasto LA, Colangelo D, Rossi B, et al. Post-operative spondylodiscitis. Eur Rev Med Pharmacol Sci 2012;16:50e7. [30] McDermott H, Bolger C, Humphreys H. Postprocedural discitis of the vertebral spine: challenges in diagnosis, treatment and prevention. J Hosp Infect 2012;82:152e7. [31] Laratta JL, Shillingford JN, Hardy N, et al. Intrawound tobramycin powder eradicates surgical wound contamination: an in vivo rabbit study. Spine (Phila Pa 1976) 2017;42:1393e7. [32] Chiang HY, Herwaldt LA, Blevins AE, et al. Effectiveness of local vancomycin powder to decrease surgical site infections: a meta-analysis. Spine J 2014;14:397e407. [33] Xiong L, Pan Q, Jin G, et al. Topical intrawound application of vancomycin powder in addition to intravenous administration of antibiotics: a meta-analysis on the deep infection after spinal surgeries. Orthop Traumatol Surg Res 2014;100:785e9. [34] Shaffer WO, Baisden JL, Fernand R, Matz PG. North American Spine Society. An evidence-based clinical guideline for antibiotic prophylaxis in spine surgery. Spine J 2013;13:1387e92. [35] Hida T, Ando K, Kobayashi K, et al. Intrawound vancomycin powder as prophylaxis of surgical site infection after invasive spine surgery with a high risk of infection. Nagoya J Med Sci 2017;79: 545e50. [36] Sweet FA, Roh M, Sliva C. Intrawound application of vancomycin for prophylaxis in instrumented thoracolumbuar fusions: efficacy, drug levels and patient outcomes. Spine (Phila Pa 1976) 2011;36: 2084e8. [37] O’Neil KR, Smith JG, Abtahi AM, et al. Reduced surgical site infections in patients undergoing posterior spinal stabilization of traumatic injuries using vancomycin powder. Spine J 2011;11: 641e6. [38] Takemoto R, Lonner B, Andres T, et al. Appropriateness of twentyfour-hour antibiotic prophylaxis after spinal surgery in which a drain is utilized. J Bone Joint Surg 2015;97:979e86. [39] Sharma S, Wu C, Andersen T, et al. Prevalence of complications in neuromuscular scoliosis surgery: a literature meta-analysis from the past 15 years. Eur Spine J 2013;22:1230e49.