Effect of bispectral index on intra-operative awareness: A meta-analysis of randomized controlled studies.

Background: Randomized controlled trials (RCTs) investigating the efficacy of bispectral index (BIS) to reduce intra-operative awareness (IOA) have reported conflicting results. The purpose of this meta-analysis is to consolidate results from RCTs to assess the efficacy of BIS in reducing IOA when compared to controls. Secondary outcomes included time to extubation, time to spontaneous and/or verbal eye opening, PACU discharge time, and utilization of inhaled anesthetics. Methods: RCTs which reported on one of the primary and/or secondary outcomes were included. Literature search utilized keywords "randomized control trial" and "intraoperative awareness." Meta-analysis was performed using RevMan 5. Results: Twenty-seven RCTs were included in the study with a total of 35,585 patients, with 18,146 patients in the BIS and 17,439 in the control group. Eighteen of 14,062 patients (0.12%) and 42 of 16,765 (0.25%) reported definite IOA in the BIS and control group, respectively, with no statistically significant difference. BIS was effective in reducing the time to spontaneous eye opening by an average of 1.3 minutes and the time to extubation by an average of 1.97 minutes. There was no difference in PACU discharge times among the groups. There was a significant decrease in consumption of sevoflurane but no difference in desflurane and propofol compared to the control group. Conclusion: While BIS monitoring results in decreased incidence of intra-operative awareness by half, it was not statistically significant. BIS provides modest benefits with regard to reducing the time to extubation, the time to spontaneous eye opening, and consumption of sevoflurane.Level of evidence: I.

Effect of intraoperative methadone vs other opioids on postoperative outcomes: a meta-analysis of randomized controlled studies.

ABSTRACT: Recent randomized controlled trials comparing the efficacy between intraoperative methadone and other opioids on postoperative outcomes have been limited by their small sample sizes and conflicting results. We performed a meta-analysis on randomized controlled trials which investigated outcomes between methadone and an opioid control group. Primary outcome data included postoperative opioid consumption, number of patients who received postoperative opioids, time to first analgesic, and pain scores. Secondary outcomes included time to extubation and incidence of nausea, vomiting, and respiratory depression. Statistical analysis was performed using RevMan. A P < 0.05 was considered statistically significant. Nine studies comprising 632 patients were included. There was no statistically significant reduction in opioid consumption postoperatively between the groups. Forty-seven percentage of patients in the methadone group received a dose of opioid postoperatively compared with 55% in the other opioids control group, which was not statistically significant. (P = 0.25) There was no difference in average time to receiving first postoperative analgesic among the groups. Pain scores within 24 hours were significantly lower in the methadone group when compared with other opioids (8 studies, n = 622, -0.49 [-0.74, -0.23], P = 0.002). However, there was no difference between 24 and 72 hours. There was no difference among the groups with respect to extubation time, nausea, vomiting, or respiratory depression. This meta-analysis concludes that there is currently insufficient evidence for the use of intraoperative methadone, when compared with other opioids. Although there was a decrease in average pain scores with methadone when compared with controls at 24 hours, there was no difference between 24 and 72 hours.

Lead extrusion ten months after spinal cord stimulator implantation: a case report.

OBJECTIVES: The purpose of this case report is to describe an occurrence of a rare complication of lead extrusion, which was observed 10 months after spinal cord stimulator (SCS) implantation. METHODS: A patient with low back pain and failed back surgery syndrome underwent implantation of a SCS without complications. Ten months after implantation, one SCS lead extruded from her lower back leading to surgical removal of the leads. RESULTS: After identifying the complication of a SCS lead extruding from the patient's back, a surgical revision was performed to remove the SCS leads but retain the implantable pulse generator (IPG) in the gluteal region. During the surgery, it was noted that the anchors were in the appropriate position, sutured and fibrosed to a deep fascial layer. There were no complications from the surgical revision and no infectious process was observed. CONCLUSIONS: We report the occurrence and management of a rare complication of SCS lead extrusion after SCS implantation for failed back surgery syndrome. After recognition, removal of the leads with retention of the IPG was able to effectively resolve the complication. The revising procedure was well tolerated but resulted in the recurrence of the patient's previous low back pain. We believe that knowledge of this case and its management will aid future physicians in the recognition and management of this rare complication of SCS implantation. Furthermore, as there is a paucity of literature discussing the management of lead extrusion after SCS implantation, we hope that this case report will spur additional research on the management of this complication.

Efficacy of intraoperative cell salvage in spine surgery: a meta-analysis.

OBJECTIVE: Intraoperative cell salvage systems, or cell savers, are widely used for the management of blood loss in patients undergoing spine surgery. However, recent studies report conflicting evidence of their efficacy. The purpose of the meta-analysis was to investigate the efficacy of cell savers in reducing blood transfusion requirements in patients undergoing spine surgery. METHODS: Both retrospective and prospective studies that investigated the efficacy of cell savers in reducing transfusion requirements in spine surgery patients when compared with control patients were identified from MEDLINE, Embase, Cochrane Collaboration Library, Google Scholar, and Scopus databases. Outcome data extracted included number of patients receiving allogenic transfusions (transfusion rate); units of allogenic transfusions; postoperative hemoglobin; costs; operative time; and complications. RevMan 5 software was used to perform statistical analyses. A random-effects model was used to calculate pooled odds ratios (with 95% CIs) and weighted mean differences (WMDs [95% CI]) for dichotomous and continuous variables, respectively. RESULTS: Eighteen studies with 2815 patients in total were included in the meta-analysis. During spine surgery, the use of intraoperative cell salvage did not reduce the intraoperative (OR 0.66 [95% CI 0.30, 1.41]), postoperative (OR -0.57 [95% CI 0.20, 1.59]), or total transfusion (OR 0.92 [95% CI 0.43, 1.98]) rate. There was a reduction in the number of allogenic units transfused intraoperatively by a mean of 0.81 (95% CI -1.15, -0.48). However, there were no differences in the number of units transfused postoperatively (WMD -0.02 [95% CI -0.41, 0.38]) or the total units transfused (WMD 0.08 [95% CI -1.06, 1.22]). There were also no differences in operative time (WMD 19.36 [95% CI -2.43, 42.15]) or complications reported (OR 0.79 [95% CI 0.46, 1.37]) between groups. A difference in postoperative hemoglobin (WMD 0.54 [95% CI 0.11, 0.98]) between both groups was observed. CONCLUSIONS: Cell saver is efficacious at reducing intraoperative allogenic units transfused. There is no difference in transfusion rates, postoperative units transfused, and the total number of units transfused. Further cost analysis studies are necessary to evaluate the cost-effectiveness of this method of blood conservation.■ CLASSIFICATION OF EVIDENCE Type of question: therapeutic; study design: meta-analysis; strength of recommendation: low.

Approach to learning and educational environment: time to rethink measurement tools in postgraduate medical training?

OBJECTIVES: To assess the correlation between perception of the learning environment and the approach to learning adopted by anesthesiology residents throughout training in an academic institution in the United States. METHODS: This is a cross-sectional study involving forty-one anesthesiology residents who completed electronic forms of the Revised Two-Factor Study Process Questionnaire to assess learning approaches, and the Dundee Ready Educational Environment Measure questionnaire to assess learning environment. Convenience sampling was used with the current anesthesiology residents. Learning approaches were analyzed with a multiple regression model for correlation between total score, domains, and training level. Analysis of variance was used to assess differences in perception of the learning environment based on training level. Multivariate logistic regression was used to assess the correlation between domains of learning the environment and approaches questionnaires. Cronbach α was used to evaluate the internal consistency of responses within each domain of both questionnaires. RESULTS: Forty-one residents completed the questionnaires. Cronbach α varied between 0.604 and 0.76 among the domains in the Study Process Questionnaire and was greater than 0.60 for the Dundee questionnaire. There was a moderate correlation between total deep approach scores and the total subjective perception of teachers scores (R2= - 0.507, p <0.01). There was no significant association between specific domains of Dundee and study process questionnaires and resident year of training. CONCLUSIONS: The learning approaches adopted by anesthesiology residents and the perception of the educational environment are not correlated with years of training. The DREEM and R-SPQ-2F questionnaires should not be recommended for evaluation of anesthesiology residents.

Color your epidural: color flow Doppler to confirm labor epidural needle position.

BACKGROUND: Labor epidural analgesia success depends on precise needle position placement within the epidural space, with reported failure rates to be as high as 32%. In this study, we describe a novel technique employing color Doppler to aid in the confirmation of the correct position of the epidural needle tip. METHODS: Retrospective evaluation of 35 patients who received labor combined spinal-epidural (CSE) with confirmation of epidural needle position with color flow Doppler (CFD) ultrasonography. Demographic data, intervertebral level of insertion and dermatome sensory level were extracted. Video and image evaluation of CFD patterns were used to confirm epidural needle tip and catheter position. CFD was used to visualize intrathecal injection of local anesthetic in two patients. RESULTS: Three different color flow patterns were visualized after the loss of resistance technique: visualization of a red and blue mosaic adjacent to the posterior complex, a mosaic pattern enveloping the trajectory of the epidural needle, and a linear deeper mosaic color pattern during spinal injection in relation to the posterior complex. Identification of epidural needle tip and epidural catheter tip occurred in 77% and 37.1% of patients, respectively. CONCLUSIONS: CFD is a novel and useful technique to confirm the precise position of the epidural needle tip in the context of labor analgesia. Identification of the epidural catheter with CFD is difficult despite an adequate CSE technique.

Anesthetic and obstetric outcomes in pregnant women undergoing cesarean delivery according to body mass index: Retrospective analysis of a single-center experience.

AIM: To evaluate maternal, neonatal and anesthetic outcomes according to BMI in women undergoing cesarean section. BACKGROUND: Increased incidence rates of obesity and morbid obesity have been reported in the United States. Pregnant obese patients are at increased risk of maternal and fetal complications, and obstetric and anesthetic management of these patients is especially challenging. METHODS: A retrospective chart review of patients who underwent cesarean section in a single center between 2015 and 2016 was conducted. Anesthetic, obstetric and neonatal outcomes were analyzed in relation to levels of BMI. RESULTS: Seven hundred and seventy one patients underwent cesarean section during the study period. The number of patients with normal BMI, obesity and morbid obesity was 213 (27.6%), 365 (47.3%) and 193 (25%), respectively. Sixty-one percent of the patients in morbidly obese group had at least one comorbidity (p < 0.01). We found no significant differences with respect to perioperative obstetric complications. Intraoperative blood loss was significantly higher in the morbidly obese group. CONCLUSION: Increasing BMI is associated with comorbidities such as hypertension and diabetes mellitus, and with increased intraoperative blood loss. We were unable to detect differences in other obstetric, anesthetic and neonatal outcomes.

Intraoperative Spinal Cord and Nerve Root Monitoring: A Hospital Survey and Review.

Intraoperative monitoring (IOM) of spinal cord and nerve root injury through somatosensory evoked potentials (SSEP), transcranial motor evoked potentials (TcMEP), spontaneous electromyography (sEMG), and triggered electromyography (tEMG) modalities is vital during spinal surgery. However, there are currently no practice guidelines or practice patterns for the utilization of unimodal and multimodal IOM for specific surgeries. This study reviews IOM modalities and documents practice patterns of spine surgeons at our single-center tertiary hospital about their use of various IOM modalities on 23 spinal procedures. As different intraoperative monitoring modalities have shown to have different sensitivities and specificities, devising practice guidelines for IOM utilization in specific spinal procedures should be considered.

Association between compensation status and outcomes in spine surgery: a meta-analysis of 31 studies.

BACKGROUND CONTEXT: Numerous studies have demonstrated poorer outcomes in patients with Workers' compensation (WC) when compared with those without WC following treatment of various of health conditions, including spine disorders. It is thus important to consider compensation status when assessing treatment outcomes in spine surgery. However, reported strengths of association have varied significantly (1.31-7.22). PURPOSE: The objective of this study was to evaluate the association of unsatisfactory outcomes on compensation status in spine surgery patients. STUDY DESIGN/SETTING: A meta-analysis was performed. PATIENT SAMPLE: Patient sample is not applicable in this study. OUTCOME MEASURE: Demographics, type of surgery, country, follow-up time, patient satisfaction, return to work and non-union events were the outcome measures. METHODS: Both prospective and retrospective studies that compared outcomes between compensated and non-compensated patients in spine surgery were included. Two independent investigators extracted outcome data. The meta-analysis was performed using Revman software. Random effects model was used to calculate risk ratio (RR, 95% confidence interval [CI]) for dichotomous variables. RESULTS: Thirty-one studies (13 prospective; 18 retrospective) with a total of 3,567 patients were included in the analysis. Follow-up time varied from 4 months to 10 years. Twelve studies involved only decompression; the rest were fusion. Overall RR of an unsatisfactory outcome was 2.12 [1.74, 2.58; p<.001] in patients with WC when compared with those without WC after surgery. The RR of an unsatisfactory outcome in patients with WC, compared with those without, was 2.09 [1.38, 3.17]; p<.01 among studies from Europe and Australia, and 2.14 [1.48, 2.60]; p<.01 among US studies. The RR of decompression-only procedures was 2.53 [1.85, 3.47]; p<.01,and 1.79 [1.45, 2.21]; p<.01 for fusion. Forty-three percent (209 of 491) of patients with WC did not return to work versus 17% (214 of 1250) of those without WC (RR 2.07 [1.43, 2.98]; p<.001). Twenty-five percent (74 of 292) and 13.5% (39 of 287) of patients had non-union in the compensated and non-compensated groups, respectively. This was not statistically significant (RR 1.33 [0.92, 1.91]; p=.07). CONCLUSIONS: Workers' compensation patients have a two-fold increased risk of an unsatisfactory outcome compared with non-compensated patients after surgery. This association was consistent when studies were grouped by country or procedure. Compensation status must be considered in all surgical intervention studies.

Post Reconstruction Breast Pyoderma Gangrenosum: Early Recognition and Prosthesis Salvage.

We report 3 cases of breast pyoderma gangrenosum in patients undergoing total mastectomy with immediate reconstruction. All three received systemic corticosteroid treatment, resulting in resolution of symptoms. As experience grew, early diagnosis in the third patient helped prosthesis salvage and timely return to the original course of reconstruction. This represents the first report of prosthesis salvage from post breast reconstruction pyoderma gangrenosum, and it demonstrates that implant removal is not always necessary during management of this rare condition.

Ninety-day readmissions after degenerative cervical spine surgery: A single-center administrative database study.

BACKGROUND: Unplanned hospital readmissions result in significant clinical and financial burdens to patients and the healthcare system. Readmission rates and causes have been investigated using large administrative databases which have certain limitations in data reporting and coding. The objective of this study was to provide a description of 90 day post-discharge readmissions following surgery for common degenerative cervical spine pathologies at a large-volume tertiary hospital. The study also compared the readmission rates of patients who underwent anterior- and posterior-approach procedures. METHODS: The administrative records from a single-center, high-volume tertiary institution were queried using ICD-9 codes for common cervical pathology over a three year period to determine the rate and causes of readmissions within the 90 days following the index surgery. RESULTS: A total of 768 patients underwent degenerative cervical spine surgery during the three year study period. Within 90 days of discharge, 24 (3.13%) patients were readmitted; 16 (2.06%) readmissions were planned for lumbar surgery; 8 (1.04%) readmissions were unplanned. 640 patients underwent procedures involving an anterior approach and 128 patients underwent procedures involving a posterior approach. There were 14 (2.17%) planned readmissions in the anterior group and 2 (1.5%) in the posterior group. The unplanned readmission rate was 0.63% (4 patients) and 3.13% (4 patients) in the anterior and posterior groups, respectively. (p=0.0343). CONCLUSION: The 90 day post-discharge unplanned readmission rate that followed elective degenerative cervical spine surgery was 1.04%. The unplanned readmission rate associated with posterior-approach procedures (3.13%) was significantly higher than that of anterior-approach procedures (0.63%). LEVEL OF EVIDENCE: IV.

Antifibrinolytics reduce blood loss in adult spinal deformity surgery: a prospective, randomized controlled trial.

STUDY DESIGN: This is a prospective, randomized, double-blinded comparison of tranexamic acid (TXA), epsilon aminocaproic acid (EACA), and placebo used intraoperatively in patients with adult spinal deformity. OBJECTIVE: The purpose of this study was to provide high-quality evidence regarding the comparative efficacies of TXA, EACA, and placebo in reducing blood loss and transfusion requirements in patients undergoing posterior spinal fusion surgery. SUMMARY OF BACKGROUND DATA: Spine deformity surgery usually involves substantial blood loss. The antifibrinolytics TXA and EACA have been shown to improve hemostasis in large blood loss surgical procedures. METHODS: Fifty-one patients undergoing posterior spinal fusion of at least 5 levels for correction of adult spinal deformity were randomized to 1 of 3 treatment groups. Primary outcome measures included intraoperative estimated blood loss, total loss, (estimated blood loss + postoperative blood loss), and transfusion rates. RESULTS: Patients received TXA (n = 19), EACA (n = 19), or placebo (n = 13) in the operating room (mean ages: 60, 47, and 43 yr, respectively); TXA patients were significantly older and had larger estimated blood volumes than both other groups. Total losses were significantly reduced for EACA versus control, and there was a demonstrable but nonsignificant trend toward reduced intraoperative blood loss in both antifibrinolytic arms versus control. EACA had significant reductions in postoperative blood transfusions versus TXA. CONCLUSION: The findings in this study support the use of antifibrinolytics to reduce blood loss in posterior adult spinal deformity surgery. LEVEL OF EVIDENCE: 1.

Unplanned hospital readmission after surgical treatment of common lumbar pathologies: rates and causes.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: To assess the rate and causes of unplanned readmissions after surgical treatment of common degenerative lumbar pathologies within 90 days. SUMMARY OF BACKGROUND DATA: With pay-for performance and bundled payment compensation models being implemented; there is a growing emphasis to decrease the number of unplanned readmissions after surgery. Reports on degenerative lumbar spine pathology readmission rates are often obtained from national databases that lack clinical detail. Less published are the results from single-center institutions. METHODS: Hospital administrative database from a single-tertiary institution was queried to identify patients who underwent surgery for 6 common lumbar pathologies during a period from 2011 to 2013. All readmissions within 90 days of discharge were reviewed for cause and rate of unplanned readmissions was calculated. RESULTS: A total of 1306 patients were identified who underwent surgery for various lumbar pathologies during a 2-year time period. There were a total of 70 readmissions captured in the database that included 14 planned, 43 unplanned readmissions, and 13 coding errors. The unplanned readmission rate varied between 2.1% and 7.1% depending on pathology, with an overall rate of 3.3% within 90 days of discharge. Index length of stay, discharge disposition, severity of illness scores, and surgical approach were associated with readmission. The addition of fusion to decompression procedures did not seem to increase readmission rates. Surgical site infections and wound complications were the 2 most common reasons for readmissions accounting for 72% of all readmissions during the 90-day postdischarge period. CONCLUSION: The rate of readmission after surgery for common lumbar degenerative pathologies is relatively low. Surgical site infections and wound complications were the most common cause of readmission in this patient cohort. LEVEL OF EVIDENCE: 4.

Efficacy of tranexamic acid on surgical bleeding in spine surgery: a meta-analysis.

BACKGROUND CONTEXT: Spine surgery is usually associated with large amount of blood loss, necessitating blood transfusions. Blood loss-associated morbidity can be because of direct risks, such as hypotension and organ damage, or as a result of blood transfusions. The antifibrinolytic, tranexamic acid (TXA), is a lysine analog that inhibits activation of plasminogen and has shown to be beneficial in reducing surgical blood loss. PURPOSE: To consolidate the findings of randomized controlled trials (RCTs) investigating the use of TXA on surgical bleeding in spine surgery. STUDY DESIGN: A metaanalysis. STUDY SAMPLE: Randomized controlled trials investigating the effectiveness of intravenous TXA in reducing blood loss in spine surgery, compared with a placebo/no treatment group. METHODS: MEDLINE, Embase, Cochrane controlled trials register, and Google Scholar were used to identify RCTs published before January 2014 that examined the effectiveness of intravenous TXA on reduction of blood loss and blood transfusions, compared with a placebo/no treatment group in spine surgery. Metaanalysis was performed using RevMan 5. Weighted mean difference with 95% confidence intervals was used to summarize the findings across the trials for continuous outcomes. Dichotomous data were expressed as risk ratios with 95% confidence intervals. A p<.05 was considered statistically significant. RESULTS: Eleven RCTs were included for TXA (644 total patients). Tranexamic acid reduced intraoperative, postoperative, and total blood loss by an average of 219 mL ([-322, -116], p<.05), 119 mL ([-141, -98], p<.05), and 202 mL ([-299, -105], p<.05), respectively. Tranexamic acid led to a reduction in proportion of patients who received a blood transfusion (risk ratio 0.67 [0.54, 0.83], p<.05) relative to placebo. There was one myocardial infarction (MI) in the TXA group and one deep vein thrombosis (DVT) in placebo. CONCLUSIONS: Tranexamic acid reduces surgical bleeding and transfusion requirements in patients undergoing spine surgery. Tranexamic acid does not appear to be associated with an increased incidence of pulmonary embolism, DVT, or MI.

Low harvest pressure enhances autologous fat graft viability.

Autologous fat grafting has been widely used in reconstructive and cosmetic surgery. Harvesting techniques play a key role in graft viability and outcomes. The authors investigated the effect of harvest pressure on adipocyte survival and viability of the surviving cells. Abdominal lipoaspiration was performed at high pressure (-760 mmHg) and low pressure (-250 mmHg) on three patients. Adipocyte survival and cell viability were measured. Adipocyte count immediately after harvest was 47 percent higher when aspirated at low pressure compared with high pressure. In addition, the cell viability was significantly higher at day 7 with low-pressure aspiration. The authors also describe a simple technique for aspirating at low pressures to obtain a controlled, consistent, reproducible, and good quality graft.

Velocity drop in anconeus epitrochlearis-associated cubital tunnel syndrome.

The anconeus epitrochlearis (AE) muscle is a common anatomical variation in the cubital tunnel retinaculum of the elbow with an incidence of up to 28%; it is one cause of compressive ulnar neuropathy. In this study, we report the significance of preoperative recognition of AE-associated cubital tunnel syndrome, based on the grade of velocity drop of the compressed ulnar nerve in electrophysiological studies. Twenty-two cases with idiopathic cubital tunnel compression (CTC) were retrospectively analyzed; AE was present in 6 cases. Velocity drop of the ulnar nerve was calculated by dividing the difference in velocity (m/s) by distance (cm); the results were classified into the following grades: + (0-2.99 m/s per cm) and ++ (< 3.00 m/s per cm). Categorical data were compared using Fisher's exact test; the Mann-Whitney U test was used to determine statistical significance of ordinal data. In patients with AE-associated CTC, 3 of the 6 (50%) cases had grade ++ velocity drop. In comparison, only 1 patient of the 16 non-AE cases (6%) had grade ++ velocity drop (P = .046). Preoperative nerve velocity conduction studies that show grade ++ velocity drop (< 3.00 m/s per cm) in ulnar nerve are highly suggestive of the presence of AE.

Lubricin and smooth muscle α-actin-containing myofibroblasts in the pseudomembranes around loose hip and knee prostheses.

The objective was to evaluate the presence and distribution of the lubricating and anti-adhesion glycoprotein lubricin and cells containing the contractile isoform smooth muscle α-actin (SMA) in pseudomembranes around loose hip prostheses. Periprosthetic tissue was obtained at revision arthroplasty of eight aseptic, loose hip implants, and for comparison three loose knee prostheses. Immunohistochemical analysis was performed in 3 zones: zone 1, within 300µm of the edge of the implant-tissue interface; zone 2, between zones 1 and 3; zone 3, within 300µm of the resected/trimmed edge. The presence of lubricin was extensive in all samples: (1) as a discrete layer at the implant-tissue interface; (2) within the extracellular matrix (ECM); (3) intracellularly. There was significantly more high grade (>50%) lubricin surface staining at the implant-tissue interface compared with the resected edge. While there was also a significant effect of location of high grade ECM lubricin staining, there was no significant effect of implant type (i.e. hip versus knee). All but two hip pseudomembrane samples showed the presence of many SMA-containing cells. There was a significant effect of location on the number of SMA-expressing cells, but not of implant type. These findings might explain why the management of loose prosthesis is so challenging.

Evaluation and treatment of failed carpal tunnel release.

Treatment failure and complications are encountered in 1% to 25% of all carpal tunnel releases. Besides hematoma, infection, skin necrosis, and intraoperative iatrogenic injuries, persistence and recurrence should be included in this discussion. Persistence is often related to incomplete release. Similar symptoms recurring after a symptom-free interval of 6 months are considered recurrent and may be caused by intraneural or perineural scarring. Adequate diagnosis and treatment of these failures can be challenging. Operative release is the main treatment consisting of complete decompression of the median nerve. In some circumstances, coverage of the median nerve may be necessary.