Spinner, Robert J.

If a single picture is worth a thousand words, then a video, by logical extension, would be priceless. This edition showcases peripheral nerve surgery in all its grandeur and preserves it for posterity. Classic and novel surgical techniques are shown related to tumor biopsy or resection; nerve decompression for entrapment; and nerve reconstruction with direct repair or nerve transfer. Akin to a nautical chart filled with detailed maps for sailors, this Neurosurgical Focus Video Atlas provides navigational tools for neurosurgeons. The shared underlying message is that a sound knowledge of anatomy can lead to innovation (i.e., creative approaches or solutions) and excellence (i.e., improved patient outcomes).

OBJECTIVEReconstructive options for brachial plexus lesions continue to expand and improve. The purpose of this study was to evaluate the prevalence and quality of restored elbow extension in patients with brachial plexus injuries who underwent transfer of the spinal accessory nerve to the motor branch of the radial nerve to the long head of the triceps muscle with an intervening autologous nerve graft and to identify patient and injury factors that influence functional triceps outcome.METHODSA total of 42 patients were included in this retrospective review. All patients underwent transfer of the spinal accessory nerve to the motor branch of the radial nerve to the long head of the triceps muscle as part of their reconstruction plan after brachial plexus injury. The primary outcome was elbow extension strength according to the modified Medical Research Council muscle grading scale, and signs of triceps muscle recovery were recorded using electromyography.RESULTSWhen evaluating the entire study population (follow-up range 12–45 months, mean 24.3 months), 52.4% of patients achieved meaningful recovery. More specifically, 45.2% reached Grade 0 or 1 recovery, 19.1% obtained Grade 2, and 35.7% improved to Grade 3 or better. The presence of a vascular injury impaired functional outcome. In the subgroup with a minimum follow-up of 20 months (n = 26), meaningful recovery was obtained by 69.5%. In this subgroup, 7.7% had no recovery (Grade 0), 19.2% had recovery to Grade 1, and 23.1% had recovery to Grade 2. Grade 3 or better was reached by 50% of patients, of whom 34.5% obtained Grade 4 elbow extension.CONCLUSIONSTransfer of the spinal accessory nerve to the radial nerve branch to the long head of the triceps muscle with an interposition nerve graft is an adequate option for restoration of elbow extension, despite the relatively long time required for reinnervation. The presence of vascular injury impairs functional recovery of the triceps muscle, and the use of shorter nerve grafts is recommended when and if possible.

OBJECTIVEThis study aimed to define a set of clinicoradiological parameters with a high specificity for the diagnosis of intraneural perineurioma, obviating the need for operative tissue diagnosis.METHODSThe authors retrospectively reviewed MR images obtained in a large cohort of patients who underwent targeted fascicular biopsy and included only those patients for whom the biopsy yielded a diagnosis. Clinical and radiological findings were then tested for their ability to predict a tissue diagnosis of intraneural perineurioma. The authors propose a new set of diagnostic criteria, referred to as the Perineurioma Diagnostic Criteria. The sensitivity, specificity, positive predictive value, and negative predictive value of several clinicoradiological methods of diagnosis were compared.RESULTSA total of 195 patients who underwent targeted fascicular biopsy were included in the cohort, of whom 51 had a tissue diagnosis of intraneural perineurioma. When the clinicoradiological methods used in this study were compared, the highest sensitivity (0.86), negative predictive value (0.95), and F1 score (0.88) were observed for the decision trees generated in C5.0 and rPart, whereas the highest specificity (1.0) and positive predictive value (1.0) were observed for the Perineurioma Diagnostic Criteria.CONCLUSIONSThis study identified clinical and radiological features that are associated with a diagnosis of perineurioma. The Perineurioma Diagnostic Criteria were determined to be the following: 1) no cancer history, 2) unifocal disease, 3) moderate to severe hyperintensity on T2-weighted MR images, 4) moderate to severe contrast enhancement, 5) homogeneous contrast enhancement, 6) fusiform shape, 7) enlargement of the involved nerves, and 8) age ≤ 40 years. Use of the Perineurioma Diagnostic Criteria obviates the need for tissue diagnosis when all of the criteria are satisfied.

Inflammatory etiologies are becoming increasingly recognized as explanations of some neuropathies, especially those occurring in the perioperative period. Although “brachial neuritis” is known to affect extraplexal nerves, accessory nerve palsy following median sternotomy has been attributed to stretch on the nerve. To better elucidate stretch as a potential cause, a cadaveric study was performed. Two patients who developed accessory nerve palsy following median sternotomy are presented to illustrate features consistent with the diagnosis of a perioperative inflammatory neuropathy. Five adult unembalmed cadavers underwent exposure of the bilateral accessory nerves in the posterior cervical triangle. A median sternotomy was performed and self‐retaining retractors positioned. With the head in neutral, left rotation and right rotation, retractors were opened as during surgery while observing and recording any accessory nerve movements. The self‐retaining sternal retractors were fully opened to a mean inter‐blade distance of 13 cm. Regardless of head position, from the initial retractor click to maximal opening there was no gross movement of the accessory nerve on the left or right sides. Opening self‐retaining sternal retractors does not appear to stretch the accessory nerve in the posterior cervical triangle. Based on our clinical experience and cadaveric results, we believe that inflammatory conditions, (i.e., idiopathic brachial plexitis) can involve the accessory nerve, and might be triggered by surgical procedures. Clin. Anat. 31:417–421, 2018. © 2017 Wiley Periodicals, Inc.

Abstract BACKGROUND Repair of proximal hamstring avulsions requires mobilization of the sciatic nerve away from the tendon stump, which can be achieved with varying difficulty depending on the degree of scar formation and adherence. Predicting when a scarred, adherent, difficult-to-mobilize nerve will be encountered has been difficult. OBJECTIVE To identify clinical and/or radiological factors predictive of a difficult intraoperative dissection of the sciatic nerve during proximal hamstring repair. METHODS We retrospectively reviewed the medical records and preoperative magnetic resonance imaging of consecutive patients undergoing proximal hamstring repair. We compared the groups with and without a difficult sciatic nerve dissection. RESULTS The total cohort consisted of 67 patients. Factors found to increase the likelihood of a difficult sciatic nerve dissection included complete conjoint tendon avulsion, higher maximal amount of tendon retraction, higher degree of imaging abnormality in the sciatic nerve, and higher degree of circumferential relationship of hematoma to the sciatic nerve. At a threshold of 23 for the Sciatic Nerve Dissection Score, the positive and negative predictive values were 53% and 88%, respectively. For the decision tree, the positive and negative predictive values were 75% and 87%, respectively. CONCLUSION We have identified imaging factors associated with a scarred, adherent sciatic nerve that predict a difficult dissection during proximal hamstring repair. We have developed 2 novel methods—the Sciatic Nerve Dissection Score and a decision tree—that can be applied to predict the probability of a difficult sciatic nerve dissection at the time of surgical repair.

Objective: The goal of this study was to characterize the risk of intraoperative injury to the posterior femoral cutaneous nerve and to evaluate potential risk factors for injury during surgical repair of proximal hamstring injuries. Design: Retrospective cohort study. Setting: Single tertiary referral center. Patients: The cohort consisted of all patients presenting to a single institution with a proximal hamstring avulsion injury who were managed with surgical repair between January 1, 2000 and August 1, 2016. A total of 67 patients were included in the cohort. Independent Variables: Variables assessed for their association with postoperative numbness in the distribution of the posterior femoral cutaneous nerve included age, sex, body mass index, mechanism of injury, time to surgical repair, and incision used. Main Outcome Measures: The primary outcome of interest was neurologic symptoms referable to the posterior femoral cutaneous nerve. Results: Postoperatively, 13 patients (19%) developed new numbness in the distribution of the posterior femoral cutaneous nerve. One patient reported neuropathic pain and paresthesias associated with the numbness. The use of a gluteal crease incision was the only predictive factor for postoperative numbness in the posterior femoral cutaneous nerve distribution (odds ratio 8.67; 95% confidence interval, 2.30-42.80; P = 0.001). Conclusions: The current study provides data that can be used in discussing the risks and benefits of surgical repair with patients and when weighing the pros and cons of using a gluteal crease versus longitudinal incision.