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Outcomes and Safety of Overlapping Surgery in Patients Undergoing Microvascular Decompression for Hemifacial Spasm and Trigeminal Neuralgia
Original Article
Outcomes and Safety of Overlapping Surgery in Patients Undergoing Microvascular Decompression for Hemifacial Spasm and Trigeminal Neuralgia Lingzhao Min, Mingxing Liu, Wenbo Zhang, Bangbao Tao, Qiuyang Sun, Shiting Li, Xiaoqiang Wang
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OBJECTIVE: Overlapping surgery, performed by the same primary attending surgeon asynchronously, has gained significant attention from the government and media as potentially harmful to patients. Therefore, the goal of this study was to evaluate the outcomes and safety of overlapping versus nonoverlapping microvascular decompression (MVD) operations.
overlapping surgeries had longer total surgical procedure times (HFS: standardized coefficient [ 0.066, P < 0.05; TN: standardized coefficient [ 0.086, P < 0.05). Overlapping surgery was not associated with a significant difference in operation time under microscope, mean LOS, efficacy (at discharge, 6 months, 1 year), short-term complications, and long-term complications.
METHODS: Patients who underwent MVD operations were retrospectively reviewed: 1153 with hemifacial spasm (HFS), 694 (60.2%) of whom underwent overlapping procedures, and 935 with trigeminal neuralgia (TN), 612 (65.5%) of whom underwent overlapping procedures. Collected variables included patient age, sex, side, disease duration, clinical characteristic, comorbidity, affected vessel, intraoperative neuroelectrophysiology, operation time under microscope, total surgical procedure times, mean length of stay (LOS), efficacy (at discharge, 6 months, 1 year), short-term complications, and long-term complications. c2 and t tests were performed to compare overlapping versus nonoverlapping cases, and then multivariate analysis were conducted to adjust for patient demographics, clinical characteristics, and comorbidity between the 2 groups.
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RESULTS: Patient variables (age, sex, side, disease duration, clinical characteristic, and comorbidity), affected vessel, and intraoperative neuroelectrophysiology were similar between the 2 groups. After adjustment for patient demographics, clinical characteristics, and comorbidity,
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Key words Hemifacial spasm - Microvascular decompression - Overlapping surgery - Trigeminal neuralgia -
Abbreviations and Acronyms AMR: Abnormal muscle response BAEP: Brainstem auditory evoked potential BNI: Barrow Neurologic Institute CSF: Cerebrospinal fluid DFP: Delayed facial palsy HFS: Hemifacial spasm LOS: Length of stay
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CONCLUSIONS: Overlapping MVD operations may be performed safely at our institution. Further prospective studies are needed to understand the association of overlapping surgery among MVD operations.
INTRODUCTION
O
verlapping surgery, a long-established practice in academic surgical centers, is defined as 2 operations being performed by the same primary attending surgeon asynchronously, without any overlap of the critical or key portions of the operation.1 With potential harm to patients, overlapping surgery has recently come under intense scrutiny from governments and the media. In response, a few medical institutions and researchers have investigated this practice and found no evidence of worse outcomes with overlapping surgery.2,3 However, these studies examined heterogeneous populations of patients undergoing a variety of neurosurgical procedures. Whether overlapping surgery has an effect in similar operations requires further exploration, such as microvascular
MVD: Microvascular decompression TN: Trigeminal neuralgia Neurosurgery Department, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China To whom correspondence should be addressed: Xiaoqiang Wang, M.D. [E-mail: [email protected]] Lingzhao Min and Mingxing Liu are coefirst authors. Citation: World Neurosurg. (2019). https://doi.org/10.1016/j.wneu.2019.07.092 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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ORIGINAL ARTICLE LINGZHAO MIN ET AL.
MICROVASCULAR DECOMPRESSION FOR HEMIFACIAL SPASM AND TRIGEMINAL NEURALGIA
Table 1. Patient Variables for Overlapping versus Nonoverlapping Cases HFS (1153)
TN (935)
Variable
Overlapping (n [ 694)
Nonoverlapping (n [ 459)
P
Overlapping (n [ 612)
Nonoverlapping (n [ 323)
Sex (M/F)
213/481 (30.7%/69.3%) 53.7 10.3
137/322 (29.8%/70.2%)
0.76
188/424 (30.7%/69.3%)
100/223 (31%/69%)
0.94
53.1 9.8
0.265
64.1 12.2
54.6 11.3
0.591
302/392 (43.5%/56.5%)
216/243 (47.1%/52.9%)
0.236
264/348 (43.1%/56.9%)
154/169 (47.7%/52.3%)
0.184
5.4 4.7
5.3 4.8
0.76
5.4 4.7
5.4 4.7
0.774
Age (years), mean (SD) Side (right/left) Disease duration (years), mean (SD) Number of dermatomes (mean)
P
0.163
V1 (%)
213 (34.8%)
125 (38.7%)
V2 (%)
307 (50.2)
163 (50.5%)
V3 (%)
92 (15%)
35 (10.8%)
Clinical course (onset)
0.783
Periocular
358 (51.6%)
Perioral
246 (53.6%)
53 (7.6%)
35 (7.6%)
283 (40.8%)
178 (38.8%)
Hypertension
486/208 (70%/30%)
324/135 (70.6%/29.4%)
0.839
434/178 (70.9%/29.1%)
225/98 (69.7%/30.3%)
0.689
Diabetes mellitus
654/40 (94.2%/5.8%)
436/23 (95%/5%)
0.582
577/35 (94.3%/5.7%)
307/16 (95%/5%)
0.624
Stroke
660/34 (95.1%/4.9%)
437/22 (95.2%/4.8%)
0.935
589/23 (96.2%/3.8%)
310/13 (96.0%/4.0%)
0.84
437/257 (63%/37%)
279/180 (60.8%/39.2%)
0.454
421/191 (68.8%/31.2%)
209/114 (64.7%/35.3%)
0.205
462/232 (66.6%/33.4%)
285/174 (62.1%/37.9%)
0.119
473/139 (77.3%/22.7%)
247/76 (76.5%/23.5%)
0.778
Hemifacial Comorbidities
Smoking Alcohol use
Data are n (%). P values calculated from c2 test or t test where appropriate for all categories under the particular variable. HFS, hemifacial spasm; TN, trigeminal neuralgia; SD, standard deviation.
decompression (MVD) for hemifacial spasm (HFS) and trigeminal neuralgia (TN), in which Teflon felts were inserted between the nerve and the affected vessels. To date, there has been no analysis of the efficacy and safety of overlapping surgery in the MVD literature. The aim of this study was therefore to evaluate the patient outcomes and complications of overlapping versus nonoverlapping MVD surgeries performed by a single surgeon at our institution. MATERIALS AND METHODS Data Collection In this retrospective cohort study, we enrolled 1153 patients with primary HFS and 935 patients with primary TN treated with MVD by a senior neurosurgeon (Dr. Shiting Li) of the Neurosurgery Department of Xinhua Hospital from January 1, 2014, to June 30, 2018, after excluding 29 patients with secondary facial spasm and 37 patients who were lost to follow-up. This study was approved by the Institutional Ethics Committee of Xinhua Hospital. All
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patients underwent MVD of the facial or trigeminal nerve via a routine retrosigmoid approach, and several Teflon felts were inserted between the nerve and the affected vessels. For each case, demographic information, surgical findings, neuroelectrophysiologic recordings, operation time under microscope, total procedure duration (from incision to wound closure, in minutes) and length of hospital stay (LOS, days) were retrieved from electronic medical records. Patients were included in the overlapping group if there was any degree of overlap between the operative start and end times between 2 cases with the same surgeon according to the American College of Surgeons.1 Intraoperative neuroelectrophysiology monitoring was implemented in all cases, including brainstem auditory evoked potential (BAEP) and abnormal muscle response (AMR) (only for HFS).4 If AMR persisted after the exploration of regions I to V of the facial nerve, the decompression procedure would be terminated and the patient would be considered as a case of persistent AMR. When the latency of peak V in BAEP was prolonged to 1.0 ms or longer, or persistent decreases (>50%)
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ORIGINAL ARTICLE LINGZHAO MIN ET AL.
MICROVASCULAR DECOMPRESSION FOR HEMIFACIAL SPASM AND TRIGEMINAL NEURALGIA
Table 2. Surgical Findings for Nonoverlapping versus Overlapping Cases HFS (1153)
TN (935)
Overlapping (n [ 694)
Nonoverlapping (n [ 459)
AICA
391 (56.3%)
251 (54.7%)
PICA
85 (12.2%)
53 (11.5%)
Factor
P
Affected vessel
AICA þ PICA
Overlapping (n [ 612)
Nonoverlapping (n [ 323)
55 (9%)
34 (10.5%)
0.224
0.856
14 (2%)
13 (2.8%)
1 (0.2%)
0 (0)
123 (17.7%)
77 (16.8%)
15 (2.5%)
6 (1.9%)
AICA þ vein
23 (3.8%)
18 (5.6%)
BA þ AICA
2 (0.3%)
0 (0)
BA
4 (0.7%)
3 (0.9%)
AICA þ VA
BA þ VA
4 (0.7%)
3 (0.9%)
SCA
357 (58.3)
191 (59.1%)
SCA þ AICA
63 (10.3%)
33 (10.2%)
SCA þ VA
2 (0.3%)
0 (0)
SCA þ AICA þ VA
8 (1.3%)
3 (0.9%)
SCA þ vein
21 (3.4%)
6 (1.9%)
SCA þ PICA
1 (0.2%)
0 (0)
1 (0.2%)
0 (0)
19 (3.1%)
12 (3.7%)
1 (0.2%)
0 (0)
35 (5.7%)
14 (4.3%)
26/586 (4.2%/95.8%)
18/305 (5.6%/94.4%)
PICA þ VA
45 (6.5%)
22 (4.8%)
AICA þ PICA þ VA
17 (2.4%)
16 (3.5%)
VA
15 (2.2%)
20 (4.4%)
AICA þ VA þ vein
2 (0.3%)
3 (0.7%)
PICA þ vein Vein Preoperative AMR (presence/absence)
2 (0.3%)
4 (0.9%)
128/13 (90.8%/9.2%)
313/22 (93.4%/6.6%)
0.31
Postoperative AMR (disappearance/persistence)
137/4 (97.2/2.8%)
320/15 (95.5%/4.5%)
0.40
Intraoperative BAEP (normal/abnormal)
135/6 (95.7/4.3%)
319/15 (95.5%/4.5%)
0.91
P
0.36
Data are n (%). P values calculated from c2 test. HFS, hemifacial spasm; TN, trigeminal neuralgia; AICA, anteroinferior cerebellar artery; PICA, posteroinferior cerebellar artery; VA, vertebral artery; BA, basilar artery; SCA, superior cerebellar artery; BAEP, brainstem auditory evoked potential; AMR, abnormal muscle response.
in amplitude of wave V were observed, procedures would be suspended to prevent irreversible impairment.5 Follow-Up and Clinical Assessment Follow-up data, including outcomes (at discharge, 6 months, and 1 year) and postoperative complications (at discharge and 1 year) were collected from outpatient records or by telephone. According to Kondo et al.,6 the results of MVD for HFS were divided into the following 4 grades: E-0 (complete disappearance of spasm), E-1 (occasional slight spasm), E-2 (moderate spasm, apparently persisting), E-3 (not cured). Grades E-0 and E-1 were considered successful. The Barrow Neurologic Institute (BNI) pain score was used to quantify TN symptoms: I (no pain, not taking any medications), II (occasional pain, not taking any
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medications), III (some pain, adequately controlled with medications), IV (some pain, not adequately controlled with medications), V (severe pain or no relief). BNI scores I and II were defined as good pain control and BNI scores III through V as poor pain control for analysis.7 Postoperative complications at discharge, including cerebrospinal fluid (CSF) rhinorrhea, intracranial infection, intracranial hemorrhage, wound infection, facial palsy, hearing impairment, tinnitus, vertigo, facial numbness, headache; and long-term postoperative complications, including delayed facial palsy (DFP), hearing impairment, tinnitus, vertigo, facial numbness, wound discomfort, and headache were investigated. Grade III or higher-grade facial palsy based on the House-Brackmann grading system was regarded as significant.8
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ORIGINAL ARTICLE LINGZHAO MIN ET AL.
MICROVASCULAR DECOMPRESSION FOR HEMIFACIAL SPASM AND TRIGEMINAL NEURALGIA
Table 3. Surgical Times, Patient Outcomes, and Complications for Nonoverlapping versus Overlapping Cases HFS (1153)
Factor Operation times under microscope, mean (SD) Total surgical procedure times, mean (SD) Mean LOS SD (days)
TN (935)
Overlapping (n [ 694)
Nonoverlapping (n [ 59)
P
Overlapping (n [ 612)
Nonoverlapping (n [ 323)
P
18.9 5.1
19.0 4.4
0.81
19.0 5.2
19.2 5.9
0.52
112.8 14.8
114.7 12.9
<0.01*
111.8 14.3
114.3 13.2
<0.01*
7.0 1.38
7.1 1.457
0.103
7.1 1.5
7.2 1.5
0.643
Efficacy at discharge
650/44 (93.7%/6.3%)
432/27 (94.1%/5.9%)
0.75
573/39 (93.6%/6.4%)
304/19 (94.1%/5.9%)
0.77
Efficacy at 6 months
653/41 (94.1%/5.9%)
435/24 (94.8%/5.2%)
0.63
576/36 (94.1%/5.9%)
304/19 (94.7%/5.3%)
0.70
Efficacy at 1 year
648/46 (93.4%/6.6%)
427/32 (93.0/7.0)
0.82
576/36 (94.1/5.9)
305/18 (94.4/5.6)
0.85
10/684 (1.4%/98.6%)
9/450 (2.0%/98.0%)
0.497
10/602 (1.6%/98.4%)
7/316 (2.2%/97.8%)
0.562
Intracranial infection
5/689 (0.7%/99.3%)
1/458 (0.2%/99.8%)
0.412
4/608 (0.7%/99.3%)
1/322 (0.3%/99.7%)
0.664
Intracranial hemorrhage
2/692 (0.3%/99.7%)
0/459 (0/100%)
0.52
1/611 (0.2%/99.8%)
0/323 (0/100%)
1
Wound infection
12/682 (1.7%/98.3%)
5/454 (1.1%/98.9%)
0.378
12/600 (2.0%/98.0%)
6/317 (1.9%/98.1%)
0.913
Facial palsy
40/654 (5.8%/94.2%)
27/432 (5.9%/94.1%)
0.933
15/597 (2.5%/97.5%)
8/315 (2.5%/97.5%)
0.981
Hearing impairment
33/661 (4.8%/95.2%)
22/437 (4.8%/95.2%)
0.976
12/600 (2.0%/98.0%)
7/316 (2.2%/97.8%)
0.832
Tinnitus
17/677 (2.4%/97.6%)
11/448 (2.4%/97.6%)
0.954
13/599 (2.1%/97.9%)
6/317 (1.9%/98.1%)
0.784
Vertigo
39/655 (5.6%/94.4%)
32/426 (7%/93%)
0.345
15/597 (2.5%/97.5%)
11/312 (3.4%/96.6%)
0.399
23/589 (3.8%/96.2%)
11/312 (3.4%/96.6%)
0.784
Short-term complications CSF rhinorrhea
Facial numbness Headache
28/66 (4%/96%)
18/440 (3.9%/96.1%)
0.929
33/579 (5.4%/94.6%)
22/301 (6.8%/93.2%)
0.381
Delayed facial palsy
14/680 (2.0%/98.0%)
11/448 (2.4%/97.6%)
0.665
9/603 (1.5%/98.5%)
7/316 (2.2%/97.8%)
0.435
Hearing impairment
19/675 (2.7%/97.3%)
10/449 (2.2%/97.8%)
0.553
3/609 (0.5%/99.5%)
1/322 (0.3%/99.7%)
1
Tinnitus
5/689 (0.7%/99.3%)
2/457 (0.4%/99.6%)
0.709
4/608 (0.7%/99.3%)
1/322 (0.3%/99.7%)
0.664
Vertigo
4/690 (0.6%/99.4%)
1/458 (0.2%/99.8%)
0.654
1/322 (0.3%/99.7%)
1/322 (0.3%/99.7%)
1
9/603 (1.5%/98.5%)
6/316 (1.9%/98.1%)
0.654
Long-term complications
Facial numbness Wound discomfort
8/686 (1.2%/98.8%)
7/452 (1.5%/98.5%)
0.585
18/594 (2.9%/97.1%)
9/314 (2.8%/97.2%)
0.893
Headache
10/684 (1.4%/98.6%)
5/454 (1.1%/98.9%)
0.606
14/598 (2.3%/97.7%)
8/315 (2.5%/97.5%)
0.856
Data are n (%). P values calculated from c2 test or t test where appropriate for all categories under the particular variable. HFS, hemifacial spasm; TN, trigeminal neuralgia; SD, standard deviation. *P<0.01.
Statistical Analysis All statistical analyses were performed with SPSS 22.0 software (IBM Corporation, Armonk, New York, USA). Continuous variables are presented as mean standard deviation and analyzed with the Student t test. Categoric variables are presented as frequency or percentage and analyzed with the Pearson c2 test or Fisher exact test. Multivariate analysis was carried out to determine the effect of variable (overlapping vs. nonoverlapping cases) on the outcomes and complications. We could not perform a multivariate analysis for postoperative complications
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because of the very low frequency of their outcome, including in short-term complications (intracranial infection, intracranial hemorrhage, and facial numbness in HFS) and long-term complications (hearing impairment in TN, tinnitus, and vertigo). RESULTS A total of 1153 HFS patients, of whom 694 (60.2%) underwent overlapping procedures, and 935 TN patients, of whom 612
WORLD NEUROSURGERY, https://doi.org/10.1016/j.wneu.2019.07.092
ORIGINAL ARTICLE LINGZHAO MIN ET AL.
MICROVASCULAR DECOMPRESSION FOR HEMIFACIAL SPASM AND TRIGEMINAL NEURALGIA
Table 4. Multiple Analysis for the Effect of Overlapping (n ¼ 848) versus Nonoverlapping MVD Cases (n ¼ 1471) HFS
Factor
Odds Ratio
95% CI
TN Standardized Coefficient
P
Odds Ratio
95% CI
Standardized Coefficient
P
Operation times under microscope, minutes
0.001
0.974
0.023
0.478
Total surgical procedure times, mean SD
0.066
0.026*
0.086
0.009*
Mean LOS, SD, days
0.049
0.099
0.039
0.239
Preoperative AMR
0.809
0.513e1.276
0.361
Postoperative AMR
0.825
0.474e1.434
0.494
Intraoperative BAEP
0.686
0.435e1.084
0.106
0.741
0.398e1.378
0.343
Efficacy at discharge
1.084
0.66e1.783
0.749
1.063
0.599e1.885
0.834
Efficacy at 6 months
1.14
0.677e1.92
0.622
1.103
0.605e2.01
0.75
Efficacy at 1 year
0.954
0.596e1.526
0.843
1.04
0.577e1.874
0.897
CSF rhinorrhea
0.685
0.273e1.718
0.42
0.732
0.274e1.959
0.534
Short-term complications
Wound infection
1.515
0.526e4.366
0.442
1.041
0.385e2.82
0.936
Facial palsy
0.993
0.595e1.656
0.978
1.02
0.423e2.457
0.965
Hearing impairment
0.898
0.507e1.592
0.713
0.901
0.348e2.333
0.83
Tinnitus
0.976
0.450e2.118
0.952
1.107
0.414e2.961
0.84
Vertigo
0.774
0.475e1.261
0.304
0.696
0.312e1.555
0.377
1.145
0.548e2.394
0.719
0.986
0.535e1.816
0.963
0.819
0.461e1.454
0.495
Delayed facial palsy
0.779
0.342e1.777
0.553
0.649
0.237e1.78
0.401
Hearing impairment
1.113
0.501e2.473
0.793 0.808
0.277e2.362
0.698
Wound discomfort
0.738
0.26e2.097
0.569
1.064
0.469e2.413
0.882
Headache
1.258
0.418e3.787
0.683
0.912
0.373e2.226
0.839
Facial numbness Headache Long-term complications
Facial numbness
Values on these outcomes are shown after adjustment for patient demographics, clinical characteristics, and comorbidities. For most variables, the odds ratio is shown, followed by the 95% confidence interval (in parentheses) and the P value. For numeric outcomes (operation time under microscope, surgical procedure time, and LOS), the coefficient is shown, followed by the P value. MVD, microvascular decompression; HFS, hemifacial spasm; TN, trigeminal neuralgia; CI, confidence interval; SD, standard deviation; LOS, length of stay; AMR, abnormal muscle response; BAEP, brainstem auditory evoked potential; SF, cerebrospinal fluid. *P<0.01.
(65.5%) underwent overlapping procedures underwent MVD. There were no significant differences in age, sex, side, disease duration, comorbidity, number of dermatomes, or clinical course of overlapping versus nonoverlapping procedures in the HFS and TN patients (Table 1). Table 2 presents the intraoperative findings and neuroelectrophysiologic results in the 2 groups. The affected vessels were well matched between the 2 groups. Additionally, preoperative positive AMR, BAEP, and postoperative AMR persistence showed no significant difference between the overlapping and nonoverlapping groups in HFS patients or in TN patients (Table 2).
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In unadjusted analyses, overlapping MVD for HFS and TN had significantly longer total procedure duration (HFS: 112.8 14.8 vs. 114.7 12.9, P < 0.01; TN: 111.8 14.3 vs. 114.3 13.2, P < 0.01) (Table 3). However, there was no significant difference between overlapping and nonoverlapping MVD in terms of HFS and TN. There was no significant difference between overlapping and nonoverlapping MVD in terms of LOS (Table 3). Operative outcomes and complications are summarized in Table 3. The difference in efficiency between the overlapping and nonoverlapping groups was not significant at discharge, at the 6-month follow-up visit, or at the 1-year follow-up visit in HFS
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ORIGINAL ARTICLE LINGZHAO MIN ET AL.
MICROVASCULAR DECOMPRESSION FOR HEMIFACIAL SPASM AND TRIGEMINAL NEURALGIA
and TN patients (HFS: 93.7% vs. 94.1%, P ¼ 0.75; 94.1% vs. 94.8%, P ¼ 0.63; 93.4% vs. 93.0%, P ¼ 0.82, respectively; TN: 93.6% vs. 94.1%, P ¼ 0.77; 94.1% vs. 94.7%, P ¼ 0.70; 94.1% vs. 94.4%, P ¼ 0.85, respectively). There were no statistically significant differences in surgical complications at discharge and longterm complications in HFS or TN patients. Multivariate analyses that adjusted for age, sex, side, disease duration, and comorbidity showed there was no significant difference in overlapping versus nonoverlapping MVD for the following outcomes in HFS and TN patients: operation time under microscope, LOS, efficiency rate (at discharge, 6 months, 1 year); however, overlapping procedures had significantly longer total procedure durations in HFS and TN patients (P ¼ 0.026, P ¼ 0.009, respectively) (Table 4). There was no difference in short-term complications and long-term complications (Table 4). DISCUSSION Overlapping surgery has been a routine practice at many institutions because it reduces downtime between surgical cases and facilitates scheduling of elective and urgent and/or emergency operations.9 Overlapping surgery has been a long-established practice in the Chinese medical environment, especially in big academic surgical centers. However, the relative safety of overlapping surgical procedures has been recently questioned in the public arena. Because of the controversy’s public nature, studies have been launched to evaluate the safety of overlapping surgery and have found no association between overlapping surgery and adverse outcomes.2,10,11 Consistent with previous studies, our analysis of 2088 MVD procedures revealed that patient demographics, comorbidity, affected vessel, and neuroelectrophysiologic results were similar between the overlapping and nonoverlapping groups. Another significant finding is that overlapping surgeries have longer total surgical procedure times than nonoverlapping ones, even after identified in a multivariate analysis, which is consistent with findings in general neurosurgical procedures.3,12 However, procedure times under microscope were equivalent between the overlapping and nonoverlapping groups. Possible explanations for this discrepancy include extended periods of time while an attending surgeon is working on a different overlapping case and lack of residents to perform wound closure. Nonetheless, there were no significant differences in LOS, efficacy at discharge, 6-month efficacy, 1-year efficacy, or short-term and long-term operative complications between the 2 groups, which is the cornerstone for evaluating the safety of any surgical practice, even after adjustment for patient demographics, clinical characteristics, and comorbidities. In agreement with our study, previous studies found that duration of operative time, and subsequently exposure to anesthetic, did not correlate with complications and outcomes in other surgery.13 Postoperative outcomes and complications after
REFERENCES 1. Abelson J, Saltzman J, Kowalczyk L, Allen S. Clash in the name of care. Available at: https://aaps. bostonglobe.com/spotlight/clash-inthe-name-ofcare/story/; Oct 25, 2015. Accessed March 29, 2016.
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MVD have been found to correlate with underlying patient age, comorbidities, and the indentation of the root exit zone.14,15 Taken together, these results do not support the claim that the practice of overlapping surgery is unsafe for patients in cases of MVD. On the contrary, this improved efficiency, including reducing wait times before surgery and more operations completed during daytime hours. Furthermore, in teaching institutions, overlapping cases are also associated with more resident involvement and graduated autonomy for surgeons in training, providing an invaluable learning opportunity for residents.2,3,9 The goals of MVD for HFS and TN are to separate the nerves from affected vessels using Teflon felts. As a result, complications may result in devastating facial palsy and hearing loss as improper surgical operation.16 Performing the MVD operation requires precision, coordination, and expertise that allows intricate and complex procedures to be achieved with great outcomes. Previous publications have shown that surgeons who have completed large numbers of similar operations performed operations with lower complication rates and improved outcomes.17,18 This introduction of overlapping surgery enables more patients to benefit from an attending surgeon’s specialized surgical skills. The retrospective design of this study carries all the limitations of a study of this nature, and these data come from a single department at 1 institution. It focused on a specific set of MVD operations performed by a specialized neurosurgeon in a highvolume medical center. As a result, our findings may not generalize to other institutional settings or other neurosurgeons. Besides, although these MVD operations were performed by different residents, we believe that the comparison between those operations was similar, given that they come from the same highly specialized team. In addition, given the low frequency of several complications (intracranial infection, intracranial hemorrhage, facial numbness in HFS, hearing impairment in TN, and tinnitus and vertigo), our study may be underpowered to detect a significant difference between the overlapping and nonoverlapping MVD groups. However, despite these limitations, we believe that this study is an important step toward understanding the effect of overlapping surgery on the MVD operation, demonstrating its safety, and increasing patient access to highly specialized surgical experts. CONCLUSIONS Overlapping MVD operations may be performed safely at our institution. Further prospective studies are needed to understand the association of overlapping surgery with MVD operations. ACKNOWLEDGMENT The authors thank Shiting Li for allowing to use the patient’s clinical information.
2. Guan J, Brock AA, Karsy M, et al. Managing overlapping surgery: An analysis of 1018 neurosurgical and spine cases. J Neurosurg. 2017;127: 1096-1104. 3. Zygourakis CC, Lee J, Barba J, Lobo E, Lawton MT. Performing concurrent operations in
academic vascular neurosurgery does not affect patient outcomes. J Neurosurg. 2017;127:1089-1095.
4. Zhang X, Zhao H, Ying TT, Tang YD, Zhu J, Li ST. The effects of dual abnormal muscle response monitoring on microvascular decompression in
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ORIGINAL ARTICLE LINGZHAO MIN ET AL.
patients with hemifacial spasm. World Neurosurg. 2017;101:93-98. 5. Polo G, Fischer C, Sindou MP, Marneffe V. Brainstem auditory evoked potential monitoring during microvascular decompression for hemifacial spasm: intraoperative brainstem auditory evoked potential changes and warning values to prevent hearing loss: Prospective study in a consecutive series of 84 patients. Neurosurgery. 2004;54:97-104 [discussion: 104-106]. 6. Kondo A, Date I, Endo S, et al. A proposal for standardized analysis of the results of microvascular decompression for trigeminal neuralgia and hemifacial spasm. Acta Neurochir (Wien). 2012;154: 773-778. 7. Rogers CL, Shetter AG, Fiedler JA, Smith KA, Han PP, Speiser BL. Gamma knife radiosurgery for trigeminal neuralgia: The initial experience of the Barrow Neurological Institute. Int J Radiat Oncol Biol Phys. 2000;47:1013-1019. 8. Vrabec JT, Backous DD, Djalilian HR, et al. Facial nerve grading system 2.0. Otolaryngol Head Neck Surg. 2009;140:445-450. 9. Beasley GM, Pappas TN, Kirk AD. Procedure delegation by attending surgeons performing concurrent operations in academic medical centers: Balancing safety and efficiency. Ann Surg. 2015;261:1044-1045.
MICROVASCULAR DECOMPRESSION FOR HEMIFACIAL SPASM AND TRIGEMINAL NEURALGIA
10. Sweeny L, Rosenthal EL, Light T, et al. Effect of overlapping operations on outcomes in microvascular reconstructions of the head and neck. Otolaryngol Head Neck Surg. 2017;156:627-635. 11. Howard BM, Holland CM, Mehta CC, et al. Association of overlapping surgery with patient outcomes in a large series of neurosurgical cases. JAMA Surg. 2018;153:313-321. 12. Zygourakis CC, Keefe M, Lee J, et al. Comparison of patient outcomes in 3725 overlapping vs 3633 nonoverlapping neurosurgical procedures using a single institution’s clinical and administrative database. Neurosurgery. 2017;80:257-268.
hemifacial spasm: Lessons from experience of 2040 cases. Neurosurg Rev. 2016;39:151-158 [discussion: 158]. 17. Aquina CT, Probst CP, Becerra AZ, et al. High volume improves outcomes: The argument for centralization of rectal cancer surgery. Surgery. 2016;159:736-748. 18. Yeo HL, Abelson JS, Mao J, O’Mahoney PR, Milsom JW, Sedrakyan A. Surgeon annual and cumulative volumes predict early postoperative outcomes after rectal cancer resection. Ann Surg. 2017;265:151-157.
13. Corbitt C, Skoracki RJ, Yu P, Hanasono MM. Free flap failure in head and neck reconstruction. Head Neck. 2014;36:1440-1445. 14. Liu LX, Ren YM, Ren PW, et al. Prognosis of symptoms and complications after microvascular decompression for hemifacial spasm: A singlecenter experience. World Neurosurg. 2018;118: e557-e561. 15. Kim HR, Rhee DJ, Kong DS, Park K. Prognostic factors of hemifacial spasm after microvascular decompression. J Korean Neurosurg Soc. 2009;45: 336-340. 16. Lee MH, Jee TK, Lee JA, Park K. Postoperative complications of microvascular decompression for
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Conflict of interest statement: Supported by the Science and Technology Committee of Shanghai Municipal (13ZR1426800). Received 20 June 2019; accepted 9 July 2019 Citation: World Neurosurg. (2019). https://doi.org/10.1016/j.wneu.2019.07.092 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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Outcomes and Safety of Overlapping Surgery in Patients Undergoing Microvascular Decompression for Hemifacial Spasm and Trigeminal Neuralgia Lingzhao Min, Mingxing Liu, Wenbo Zhang, Bangbao Tao, Qiuyang Sun, Shiting Li, Xiaoqiang Wang
-
OBJECTIVE: Overlapping surgery, performed by the same primary attending surgeon asynchronously, has gained significant attention from the government and media as potentially harmful to patients. Therefore, the goal of this study was to evaluate the outcomes and safety of overlapping versus nonoverlapping microvascular decompression (MVD) operations.
overlapping surgeries had longer total surgical procedure times (HFS: standardized coefficient [ 0.066, P < 0.05; TN: standardized coefficient [ 0.086, P < 0.05). Overlapping surgery was not associated with a significant difference in operation time under microscope, mean LOS, efficacy (at discharge, 6 months, 1 year), short-term complications, and long-term complications.
METHODS: Patients who underwent MVD operations were retrospectively reviewed: 1153 with hemifacial spasm (HFS), 694 (60.2%) of whom underwent overlapping procedures, and 935 with trigeminal neuralgia (TN), 612 (65.5%) of whom underwent overlapping procedures. Collected variables included patient age, sex, side, disease duration, clinical characteristic, comorbidity, affected vessel, intraoperative neuroelectrophysiology, operation time under microscope, total surgical procedure times, mean length of stay (LOS), efficacy (at discharge, 6 months, 1 year), short-term complications, and long-term complications. c2 and t tests were performed to compare overlapping versus nonoverlapping cases, and then multivariate analysis were conducted to adjust for patient demographics, clinical characteristics, and comorbidity between the 2 groups.
-
-
RESULTS: Patient variables (age, sex, side, disease duration, clinical characteristic, and comorbidity), affected vessel, and intraoperative neuroelectrophysiology were similar between the 2 groups. After adjustment for patient demographics, clinical characteristics, and comorbidity,
-
Key words Hemifacial spasm - Microvascular decompression - Overlapping surgery - Trigeminal neuralgia -
Abbreviations and Acronyms AMR: Abnormal muscle response BAEP: Brainstem auditory evoked potential BNI: Barrow Neurologic Institute CSF: Cerebrospinal fluid DFP: Delayed facial palsy HFS: Hemifacial spasm LOS: Length of stay
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CONCLUSIONS: Overlapping MVD operations may be performed safely at our institution. Further prospective studies are needed to understand the association of overlapping surgery among MVD operations.
INTRODUCTION
O
verlapping surgery, a long-established practice in academic surgical centers, is defined as 2 operations being performed by the same primary attending surgeon asynchronously, without any overlap of the critical or key portions of the operation.1 With potential harm to patients, overlapping surgery has recently come under intense scrutiny from governments and the media. In response, a few medical institutions and researchers have investigated this practice and found no evidence of worse outcomes with overlapping surgery.2,3 However, these studies examined heterogeneous populations of patients undergoing a variety of neurosurgical procedures. Whether overlapping surgery has an effect in similar operations requires further exploration, such as microvascular
MVD: Microvascular decompression TN: Trigeminal neuralgia Neurosurgery Department, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China To whom correspondence should be addressed: Xiaoqiang Wang, M.D. [E-mail: [email protected]] Lingzhao Min and Mingxing Liu are coefirst authors. Citation: World Neurosurg. (2019). https://doi.org/10.1016/j.wneu.2019.07.092 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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ORIGINAL ARTICLE LINGZHAO MIN ET AL.
MICROVASCULAR DECOMPRESSION FOR HEMIFACIAL SPASM AND TRIGEMINAL NEURALGIA
Table 1. Patient Variables for Overlapping versus Nonoverlapping Cases HFS (1153)
TN (935)
Variable
Overlapping (n [ 694)
Nonoverlapping (n [ 459)
P
Overlapping (n [ 612)
Nonoverlapping (n [ 323)
Sex (M/F)
213/481 (30.7%/69.3%) 53.7 10.3
137/322 (29.8%/70.2%)
0.76
188/424 (30.7%/69.3%)
100/223 (31%/69%)
0.94
53.1 9.8
0.265
64.1 12.2
54.6 11.3
0.591
302/392 (43.5%/56.5%)
216/243 (47.1%/52.9%)
0.236
264/348 (43.1%/56.9%)
154/169 (47.7%/52.3%)
0.184
5.4 4.7
5.3 4.8
0.76
5.4 4.7
5.4 4.7
0.774
Age (years), mean (SD) Side (right/left) Disease duration (years), mean (SD) Number of dermatomes (mean)
P
0.163
V1 (%)
213 (34.8%)
125 (38.7%)
V2 (%)
307 (50.2)
163 (50.5%)
V3 (%)
92 (15%)
35 (10.8%)
Clinical course (onset)
0.783
Periocular
358 (51.6%)
Perioral
246 (53.6%)
53 (7.6%)
35 (7.6%)
283 (40.8%)
178 (38.8%)
Hypertension
486/208 (70%/30%)
324/135 (70.6%/29.4%)
0.839
434/178 (70.9%/29.1%)
225/98 (69.7%/30.3%)
0.689
Diabetes mellitus
654/40 (94.2%/5.8%)
436/23 (95%/5%)
0.582
577/35 (94.3%/5.7%)
307/16 (95%/5%)
0.624
Stroke
660/34 (95.1%/4.9%)
437/22 (95.2%/4.8%)
0.935
589/23 (96.2%/3.8%)
310/13 (96.0%/4.0%)
0.84
437/257 (63%/37%)
279/180 (60.8%/39.2%)
0.454
421/191 (68.8%/31.2%)
209/114 (64.7%/35.3%)
0.205
462/232 (66.6%/33.4%)
285/174 (62.1%/37.9%)
0.119
473/139 (77.3%/22.7%)
247/76 (76.5%/23.5%)
0.778
Hemifacial Comorbidities
Smoking Alcohol use
Data are n (%). P values calculated from c2 test or t test where appropriate for all categories under the particular variable. HFS, hemifacial spasm; TN, trigeminal neuralgia; SD, standard deviation.
decompression (MVD) for hemifacial spasm (HFS) and trigeminal neuralgia (TN), in which Teflon felts were inserted between the nerve and the affected vessels. To date, there has been no analysis of the efficacy and safety of overlapping surgery in the MVD literature. The aim of this study was therefore to evaluate the patient outcomes and complications of overlapping versus nonoverlapping MVD surgeries performed by a single surgeon at our institution. MATERIALS AND METHODS Data Collection In this retrospective cohort study, we enrolled 1153 patients with primary HFS and 935 patients with primary TN treated with MVD by a senior neurosurgeon (Dr. Shiting Li) of the Neurosurgery Department of Xinhua Hospital from January 1, 2014, to June 30, 2018, after excluding 29 patients with secondary facial spasm and 37 patients who were lost to follow-up. This study was approved by the Institutional Ethics Committee of Xinhua Hospital. All
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patients underwent MVD of the facial or trigeminal nerve via a routine retrosigmoid approach, and several Teflon felts were inserted between the nerve and the affected vessels. For each case, demographic information, surgical findings, neuroelectrophysiologic recordings, operation time under microscope, total procedure duration (from incision to wound closure, in minutes) and length of hospital stay (LOS, days) were retrieved from electronic medical records. Patients were included in the overlapping group if there was any degree of overlap between the operative start and end times between 2 cases with the same surgeon according to the American College of Surgeons.1 Intraoperative neuroelectrophysiology monitoring was implemented in all cases, including brainstem auditory evoked potential (BAEP) and abnormal muscle response (AMR) (only for HFS).4 If AMR persisted after the exploration of regions I to V of the facial nerve, the decompression procedure would be terminated and the patient would be considered as a case of persistent AMR. When the latency of peak V in BAEP was prolonged to 1.0 ms or longer, or persistent decreases (>50%)
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ORIGINAL ARTICLE LINGZHAO MIN ET AL.
MICROVASCULAR DECOMPRESSION FOR HEMIFACIAL SPASM AND TRIGEMINAL NEURALGIA
Table 2. Surgical Findings for Nonoverlapping versus Overlapping Cases HFS (1153)
TN (935)
Overlapping (n [ 694)
Nonoverlapping (n [ 459)
AICA
391 (56.3%)
251 (54.7%)
PICA
85 (12.2%)
53 (11.5%)
Factor
P
Affected vessel
AICA þ PICA
Overlapping (n [ 612)
Nonoverlapping (n [ 323)
55 (9%)
34 (10.5%)
0.224
0.856
14 (2%)
13 (2.8%)
1 (0.2%)
0 (0)
123 (17.7%)
77 (16.8%)
15 (2.5%)
6 (1.9%)
AICA þ vein
23 (3.8%)
18 (5.6%)
BA þ AICA
2 (0.3%)
0 (0)
BA
4 (0.7%)
3 (0.9%)
AICA þ VA
BA þ VA
4 (0.7%)
3 (0.9%)
SCA
357 (58.3)
191 (59.1%)
SCA þ AICA
63 (10.3%)
33 (10.2%)
SCA þ VA
2 (0.3%)
0 (0)
SCA þ AICA þ VA
8 (1.3%)
3 (0.9%)
SCA þ vein
21 (3.4%)
6 (1.9%)
SCA þ PICA
1 (0.2%)
0 (0)
1 (0.2%)
0 (0)
19 (3.1%)
12 (3.7%)
1 (0.2%)
0 (0)
35 (5.7%)
14 (4.3%)
26/586 (4.2%/95.8%)
18/305 (5.6%/94.4%)
PICA þ VA
45 (6.5%)
22 (4.8%)
AICA þ PICA þ VA
17 (2.4%)
16 (3.5%)
VA
15 (2.2%)
20 (4.4%)
AICA þ VA þ vein
2 (0.3%)
3 (0.7%)
PICA þ vein Vein Preoperative AMR (presence/absence)
2 (0.3%)
4 (0.9%)
128/13 (90.8%/9.2%)
313/22 (93.4%/6.6%)
0.31
Postoperative AMR (disappearance/persistence)
137/4 (97.2/2.8%)
320/15 (95.5%/4.5%)
0.40
Intraoperative BAEP (normal/abnormal)
135/6 (95.7/4.3%)
319/15 (95.5%/4.5%)
0.91
P
0.36
Data are n (%). P values calculated from c2 test. HFS, hemifacial spasm; TN, trigeminal neuralgia; AICA, anteroinferior cerebellar artery; PICA, posteroinferior cerebellar artery; VA, vertebral artery; BA, basilar artery; SCA, superior cerebellar artery; BAEP, brainstem auditory evoked potential; AMR, abnormal muscle response.
in amplitude of wave V were observed, procedures would be suspended to prevent irreversible impairment.5 Follow-Up and Clinical Assessment Follow-up data, including outcomes (at discharge, 6 months, and 1 year) and postoperative complications (at discharge and 1 year) were collected from outpatient records or by telephone. According to Kondo et al.,6 the results of MVD for HFS were divided into the following 4 grades: E-0 (complete disappearance of spasm), E-1 (occasional slight spasm), E-2 (moderate spasm, apparently persisting), E-3 (not cured). Grades E-0 and E-1 were considered successful. The Barrow Neurologic Institute (BNI) pain score was used to quantify TN symptoms: I (no pain, not taking any medications), II (occasional pain, not taking any
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medications), III (some pain, adequately controlled with medications), IV (some pain, not adequately controlled with medications), V (severe pain or no relief). BNI scores I and II were defined as good pain control and BNI scores III through V as poor pain control for analysis.7 Postoperative complications at discharge, including cerebrospinal fluid (CSF) rhinorrhea, intracranial infection, intracranial hemorrhage, wound infection, facial palsy, hearing impairment, tinnitus, vertigo, facial numbness, headache; and long-term postoperative complications, including delayed facial palsy (DFP), hearing impairment, tinnitus, vertigo, facial numbness, wound discomfort, and headache were investigated. Grade III or higher-grade facial palsy based on the House-Brackmann grading system was regarded as significant.8
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ORIGINAL ARTICLE LINGZHAO MIN ET AL.
MICROVASCULAR DECOMPRESSION FOR HEMIFACIAL SPASM AND TRIGEMINAL NEURALGIA
Table 3. Surgical Times, Patient Outcomes, and Complications for Nonoverlapping versus Overlapping Cases HFS (1153)
Factor Operation times under microscope, mean (SD) Total surgical procedure times, mean (SD) Mean LOS SD (days)
TN (935)
Overlapping (n [ 694)
Nonoverlapping (n [ 59)
P
Overlapping (n [ 612)
Nonoverlapping (n [ 323)
P
18.9 5.1
19.0 4.4
0.81
19.0 5.2
19.2 5.9
0.52
112.8 14.8
114.7 12.9
<0.01*
111.8 14.3
114.3 13.2
<0.01*
7.0 1.38
7.1 1.457
0.103
7.1 1.5
7.2 1.5
0.643
Efficacy at discharge
650/44 (93.7%/6.3%)
432/27 (94.1%/5.9%)
0.75
573/39 (93.6%/6.4%)
304/19 (94.1%/5.9%)
0.77
Efficacy at 6 months
653/41 (94.1%/5.9%)
435/24 (94.8%/5.2%)
0.63
576/36 (94.1%/5.9%)
304/19 (94.7%/5.3%)
0.70
Efficacy at 1 year
648/46 (93.4%/6.6%)
427/32 (93.0/7.0)
0.82
576/36 (94.1/5.9)
305/18 (94.4/5.6)
0.85
10/684 (1.4%/98.6%)
9/450 (2.0%/98.0%)
0.497
10/602 (1.6%/98.4%)
7/316 (2.2%/97.8%)
0.562
Intracranial infection
5/689 (0.7%/99.3%)
1/458 (0.2%/99.8%)
0.412
4/608 (0.7%/99.3%)
1/322 (0.3%/99.7%)
0.664
Intracranial hemorrhage
2/692 (0.3%/99.7%)
0/459 (0/100%)
0.52
1/611 (0.2%/99.8%)
0/323 (0/100%)
1
Wound infection
12/682 (1.7%/98.3%)
5/454 (1.1%/98.9%)
0.378
12/600 (2.0%/98.0%)
6/317 (1.9%/98.1%)
0.913
Facial palsy
40/654 (5.8%/94.2%)
27/432 (5.9%/94.1%)
0.933
15/597 (2.5%/97.5%)
8/315 (2.5%/97.5%)
0.981
Hearing impairment
33/661 (4.8%/95.2%)
22/437 (4.8%/95.2%)
0.976
12/600 (2.0%/98.0%)
7/316 (2.2%/97.8%)
0.832
Tinnitus
17/677 (2.4%/97.6%)
11/448 (2.4%/97.6%)
0.954
13/599 (2.1%/97.9%)
6/317 (1.9%/98.1%)
0.784
Vertigo
39/655 (5.6%/94.4%)
32/426 (7%/93%)
0.345
15/597 (2.5%/97.5%)
11/312 (3.4%/96.6%)
0.399
23/589 (3.8%/96.2%)
11/312 (3.4%/96.6%)
0.784
Short-term complications CSF rhinorrhea
Facial numbness Headache
28/66 (4%/96%)
18/440 (3.9%/96.1%)
0.929
33/579 (5.4%/94.6%)
22/301 (6.8%/93.2%)
0.381
Delayed facial palsy
14/680 (2.0%/98.0%)
11/448 (2.4%/97.6%)
0.665
9/603 (1.5%/98.5%)
7/316 (2.2%/97.8%)
0.435
Hearing impairment
19/675 (2.7%/97.3%)
10/449 (2.2%/97.8%)
0.553
3/609 (0.5%/99.5%)
1/322 (0.3%/99.7%)
1
Tinnitus
5/689 (0.7%/99.3%)
2/457 (0.4%/99.6%)
0.709
4/608 (0.7%/99.3%)
1/322 (0.3%/99.7%)
0.664
Vertigo
4/690 (0.6%/99.4%)
1/458 (0.2%/99.8%)
0.654
1/322 (0.3%/99.7%)
1/322 (0.3%/99.7%)
1
9/603 (1.5%/98.5%)
6/316 (1.9%/98.1%)
0.654
Long-term complications
Facial numbness Wound discomfort
8/686 (1.2%/98.8%)
7/452 (1.5%/98.5%)
0.585
18/594 (2.9%/97.1%)
9/314 (2.8%/97.2%)
0.893
Headache
10/684 (1.4%/98.6%)
5/454 (1.1%/98.9%)
0.606
14/598 (2.3%/97.7%)
8/315 (2.5%/97.5%)
0.856
Data are n (%). P values calculated from c2 test or t test where appropriate for all categories under the particular variable. HFS, hemifacial spasm; TN, trigeminal neuralgia; SD, standard deviation. *P<0.01.
Statistical Analysis All statistical analyses were performed with SPSS 22.0 software (IBM Corporation, Armonk, New York, USA). Continuous variables are presented as mean standard deviation and analyzed with the Student t test. Categoric variables are presented as frequency or percentage and analyzed with the Pearson c2 test or Fisher exact test. Multivariate analysis was carried out to determine the effect of variable (overlapping vs. nonoverlapping cases) on the outcomes and complications. We could not perform a multivariate analysis for postoperative complications
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because of the very low frequency of their outcome, including in short-term complications (intracranial infection, intracranial hemorrhage, and facial numbness in HFS) and long-term complications (hearing impairment in TN, tinnitus, and vertigo). RESULTS A total of 1153 HFS patients, of whom 694 (60.2%) underwent overlapping procedures, and 935 TN patients, of whom 612
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ORIGINAL ARTICLE LINGZHAO MIN ET AL.
MICROVASCULAR DECOMPRESSION FOR HEMIFACIAL SPASM AND TRIGEMINAL NEURALGIA
Table 4. Multiple Analysis for the Effect of Overlapping (n ¼ 848) versus Nonoverlapping MVD Cases (n ¼ 1471) HFS
Factor
Odds Ratio
95% CI
TN Standardized Coefficient
P
Odds Ratio
95% CI
Standardized Coefficient
P
Operation times under microscope, minutes
0.001
0.974
0.023
0.478
Total surgical procedure times, mean SD
0.066
0.026*
0.086
0.009*
Mean LOS, SD, days
0.049
0.099
0.039
0.239
Preoperative AMR
0.809
0.513e1.276
0.361
Postoperative AMR
0.825
0.474e1.434
0.494
Intraoperative BAEP
0.686
0.435e1.084
0.106
0.741
0.398e1.378
0.343
Efficacy at discharge
1.084
0.66e1.783
0.749
1.063
0.599e1.885
0.834
Efficacy at 6 months
1.14
0.677e1.92
0.622
1.103
0.605e2.01
0.75
Efficacy at 1 year
0.954
0.596e1.526
0.843
1.04
0.577e1.874
0.897
CSF rhinorrhea
0.685
0.273e1.718
0.42
0.732
0.274e1.959
0.534
Short-term complications
Wound infection
1.515
0.526e4.366
0.442
1.041
0.385e2.82
0.936
Facial palsy
0.993
0.595e1.656
0.978
1.02
0.423e2.457
0.965
Hearing impairment
0.898
0.507e1.592
0.713
0.901
0.348e2.333
0.83
Tinnitus
0.976
0.450e2.118
0.952
1.107
0.414e2.961
0.84
Vertigo
0.774
0.475e1.261
0.304
0.696
0.312e1.555
0.377
1.145
0.548e2.394
0.719
0.986
0.535e1.816
0.963
0.819
0.461e1.454
0.495
Delayed facial palsy
0.779
0.342e1.777
0.553
0.649
0.237e1.78
0.401
Hearing impairment
1.113
0.501e2.473
0.793 0.808
0.277e2.362
0.698
Wound discomfort
0.738
0.26e2.097
0.569
1.064
0.469e2.413
0.882
Headache
1.258
0.418e3.787
0.683
0.912
0.373e2.226
0.839
Facial numbness Headache Long-term complications
Facial numbness
Values on these outcomes are shown after adjustment for patient demographics, clinical characteristics, and comorbidities. For most variables, the odds ratio is shown, followed by the 95% confidence interval (in parentheses) and the P value. For numeric outcomes (operation time under microscope, surgical procedure time, and LOS), the coefficient is shown, followed by the P value. MVD, microvascular decompression; HFS, hemifacial spasm; TN, trigeminal neuralgia; CI, confidence interval; SD, standard deviation; LOS, length of stay; AMR, abnormal muscle response; BAEP, brainstem auditory evoked potential; SF, cerebrospinal fluid. *P<0.01.
(65.5%) underwent overlapping procedures underwent MVD. There were no significant differences in age, sex, side, disease duration, comorbidity, number of dermatomes, or clinical course of overlapping versus nonoverlapping procedures in the HFS and TN patients (Table 1). Table 2 presents the intraoperative findings and neuroelectrophysiologic results in the 2 groups. The affected vessels were well matched between the 2 groups. Additionally, preoperative positive AMR, BAEP, and postoperative AMR persistence showed no significant difference between the overlapping and nonoverlapping groups in HFS patients or in TN patients (Table 2).
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In unadjusted analyses, overlapping MVD for HFS and TN had significantly longer total procedure duration (HFS: 112.8 14.8 vs. 114.7 12.9, P < 0.01; TN: 111.8 14.3 vs. 114.3 13.2, P < 0.01) (Table 3). However, there was no significant difference between overlapping and nonoverlapping MVD in terms of HFS and TN. There was no significant difference between overlapping and nonoverlapping MVD in terms of LOS (Table 3). Operative outcomes and complications are summarized in Table 3. The difference in efficiency between the overlapping and nonoverlapping groups was not significant at discharge, at the 6-month follow-up visit, or at the 1-year follow-up visit in HFS
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ORIGINAL ARTICLE LINGZHAO MIN ET AL.
MICROVASCULAR DECOMPRESSION FOR HEMIFACIAL SPASM AND TRIGEMINAL NEURALGIA
and TN patients (HFS: 93.7% vs. 94.1%, P ¼ 0.75; 94.1% vs. 94.8%, P ¼ 0.63; 93.4% vs. 93.0%, P ¼ 0.82, respectively; TN: 93.6% vs. 94.1%, P ¼ 0.77; 94.1% vs. 94.7%, P ¼ 0.70; 94.1% vs. 94.4%, P ¼ 0.85, respectively). There were no statistically significant differences in surgical complications at discharge and longterm complications in HFS or TN patients. Multivariate analyses that adjusted for age, sex, side, disease duration, and comorbidity showed there was no significant difference in overlapping versus nonoverlapping MVD for the following outcomes in HFS and TN patients: operation time under microscope, LOS, efficiency rate (at discharge, 6 months, 1 year); however, overlapping procedures had significantly longer total procedure durations in HFS and TN patients (P ¼ 0.026, P ¼ 0.009, respectively) (Table 4). There was no difference in short-term complications and long-term complications (Table 4). DISCUSSION Overlapping surgery has been a routine practice at many institutions because it reduces downtime between surgical cases and facilitates scheduling of elective and urgent and/or emergency operations.9 Overlapping surgery has been a long-established practice in the Chinese medical environment, especially in big academic surgical centers. However, the relative safety of overlapping surgical procedures has been recently questioned in the public arena. Because of the controversy’s public nature, studies have been launched to evaluate the safety of overlapping surgery and have found no association between overlapping surgery and adverse outcomes.2,10,11 Consistent with previous studies, our analysis of 2088 MVD procedures revealed that patient demographics, comorbidity, affected vessel, and neuroelectrophysiologic results were similar between the overlapping and nonoverlapping groups. Another significant finding is that overlapping surgeries have longer total surgical procedure times than nonoverlapping ones, even after identified in a multivariate analysis, which is consistent with findings in general neurosurgical procedures.3,12 However, procedure times under microscope were equivalent between the overlapping and nonoverlapping groups. Possible explanations for this discrepancy include extended periods of time while an attending surgeon is working on a different overlapping case and lack of residents to perform wound closure. Nonetheless, there were no significant differences in LOS, efficacy at discharge, 6-month efficacy, 1-year efficacy, or short-term and long-term operative complications between the 2 groups, which is the cornerstone for evaluating the safety of any surgical practice, even after adjustment for patient demographics, clinical characteristics, and comorbidities. In agreement with our study, previous studies found that duration of operative time, and subsequently exposure to anesthetic, did not correlate with complications and outcomes in other surgery.13 Postoperative outcomes and complications after
REFERENCES 1. Abelson J, Saltzman J, Kowalczyk L, Allen S. Clash in the name of care. Available at: https://aaps. bostonglobe.com/spotlight/clash-inthe-name-ofcare/story/; Oct 25, 2015. Accessed March 29, 2016.
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MVD have been found to correlate with underlying patient age, comorbidities, and the indentation of the root exit zone.14,15 Taken together, these results do not support the claim that the practice of overlapping surgery is unsafe for patients in cases of MVD. On the contrary, this improved efficiency, including reducing wait times before surgery and more operations completed during daytime hours. Furthermore, in teaching institutions, overlapping cases are also associated with more resident involvement and graduated autonomy for surgeons in training, providing an invaluable learning opportunity for residents.2,3,9 The goals of MVD for HFS and TN are to separate the nerves from affected vessels using Teflon felts. As a result, complications may result in devastating facial palsy and hearing loss as improper surgical operation.16 Performing the MVD operation requires precision, coordination, and expertise that allows intricate and complex procedures to be achieved with great outcomes. Previous publications have shown that surgeons who have completed large numbers of similar operations performed operations with lower complication rates and improved outcomes.17,18 This introduction of overlapping surgery enables more patients to benefit from an attending surgeon’s specialized surgical skills. The retrospective design of this study carries all the limitations of a study of this nature, and these data come from a single department at 1 institution. It focused on a specific set of MVD operations performed by a specialized neurosurgeon in a highvolume medical center. As a result, our findings may not generalize to other institutional settings or other neurosurgeons. Besides, although these MVD operations were performed by different residents, we believe that the comparison between those operations was similar, given that they come from the same highly specialized team. In addition, given the low frequency of several complications (intracranial infection, intracranial hemorrhage, facial numbness in HFS, hearing impairment in TN, and tinnitus and vertigo), our study may be underpowered to detect a significant difference between the overlapping and nonoverlapping MVD groups. However, despite these limitations, we believe that this study is an important step toward understanding the effect of overlapping surgery on the MVD operation, demonstrating its safety, and increasing patient access to highly specialized surgical experts. CONCLUSIONS Overlapping MVD operations may be performed safely at our institution. Further prospective studies are needed to understand the association of overlapping surgery with MVD operations. ACKNOWLEDGMENT The authors thank Shiting Li for allowing to use the patient’s clinical information.
2. Guan J, Brock AA, Karsy M, et al. Managing overlapping surgery: An analysis of 1018 neurosurgical and spine cases. J Neurosurg. 2017;127: 1096-1104. 3. Zygourakis CC, Lee J, Barba J, Lobo E, Lawton MT. Performing concurrent operations in
academic vascular neurosurgery does not affect patient outcomes. J Neurosurg. 2017;127:1089-1095.
4. Zhang X, Zhao H, Ying TT, Tang YD, Zhu J, Li ST. The effects of dual abnormal muscle response monitoring on microvascular decompression in
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ORIGINAL ARTICLE LINGZHAO MIN ET AL.
patients with hemifacial spasm. World Neurosurg. 2017;101:93-98. 5. Polo G, Fischer C, Sindou MP, Marneffe V. Brainstem auditory evoked potential monitoring during microvascular decompression for hemifacial spasm: intraoperative brainstem auditory evoked potential changes and warning values to prevent hearing loss: Prospective study in a consecutive series of 84 patients. Neurosurgery. 2004;54:97-104 [discussion: 104-106]. 6. Kondo A, Date I, Endo S, et al. A proposal for standardized analysis of the results of microvascular decompression for trigeminal neuralgia and hemifacial spasm. Acta Neurochir (Wien). 2012;154: 773-778. 7. Rogers CL, Shetter AG, Fiedler JA, Smith KA, Han PP, Speiser BL. Gamma knife radiosurgery for trigeminal neuralgia: The initial experience of the Barrow Neurological Institute. Int J Radiat Oncol Biol Phys. 2000;47:1013-1019. 8. Vrabec JT, Backous DD, Djalilian HR, et al. Facial nerve grading system 2.0. Otolaryngol Head Neck Surg. 2009;140:445-450. 9. Beasley GM, Pappas TN, Kirk AD. Procedure delegation by attending surgeons performing concurrent operations in academic medical centers: Balancing safety and efficiency. Ann Surg. 2015;261:1044-1045.
MICROVASCULAR DECOMPRESSION FOR HEMIFACIAL SPASM AND TRIGEMINAL NEURALGIA
10. Sweeny L, Rosenthal EL, Light T, et al. Effect of overlapping operations on outcomes in microvascular reconstructions of the head and neck. Otolaryngol Head Neck Surg. 2017;156:627-635. 11. Howard BM, Holland CM, Mehta CC, et al. Association of overlapping surgery with patient outcomes in a large series of neurosurgical cases. JAMA Surg. 2018;153:313-321. 12. Zygourakis CC, Keefe M, Lee J, et al. Comparison of patient outcomes in 3725 overlapping vs 3633 nonoverlapping neurosurgical procedures using a single institution’s clinical and administrative database. Neurosurgery. 2017;80:257-268.
hemifacial spasm: Lessons from experience of 2040 cases. Neurosurg Rev. 2016;39:151-158 [discussion: 158]. 17. Aquina CT, Probst CP, Becerra AZ, et al. High volume improves outcomes: The argument for centralization of rectal cancer surgery. Surgery. 2016;159:736-748. 18. Yeo HL, Abelson JS, Mao J, O’Mahoney PR, Milsom JW, Sedrakyan A. Surgeon annual and cumulative volumes predict early postoperative outcomes after rectal cancer resection. Ann Surg. 2017;265:151-157.
13. Corbitt C, Skoracki RJ, Yu P, Hanasono MM. Free flap failure in head and neck reconstruction. Head Neck. 2014;36:1440-1445. 14. Liu LX, Ren YM, Ren PW, et al. Prognosis of symptoms and complications after microvascular decompression for hemifacial spasm: A singlecenter experience. World Neurosurg. 2018;118: e557-e561. 15. Kim HR, Rhee DJ, Kong DS, Park K. Prognostic factors of hemifacial spasm after microvascular decompression. J Korean Neurosurg Soc. 2009;45: 336-340. 16. Lee MH, Jee TK, Lee JA, Park K. Postoperative complications of microvascular decompression for
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Conflict of interest statement: Supported by the Science and Technology Committee of Shanghai Municipal (13ZR1426800). Received 20 June 2019; accepted 9 July 2019 Citation: World Neurosurg. (2019). https://doi.org/10.1016/j.wneu.2019.07.092 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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