The authors present the cases of 3 patients with severe injuries affecting the peroneal nerve combined with loss of tibialis posterior function (inversion) despite preservation of other tibial nerve function. Loss of tibialis posterior function is problematic, since transfer of the tibialis posterior tendon is arguably the best reconstructive option for foot drop, when available. Analysis of preoperative imaging studies correlated with operative findings and showed that the injuries, while predominantly to the common peroneal nerve, also affected the lateral portion of the tibial nerve/division near the sciatic nerve bifurcation. Sunderland’s fascicular topographic maps demonstrate the localization of the fascicular bundle subserving the tibialis posterior to the area that corresponds to the injury. This has clinical significance in predicting injury patterns and potentially for treatment of these injuries. The lateral fibers of the tibial division/nerve may be vulnerable with long stretch injuries. Due to the importance of tibialis posterior function, it may be important to perform internal neurolysis of the tibial division/nerve in order to facilitate nerve action potential testing of these fascicles, ultimately performing split nerve graft repair when nerve action potentials are absent in this important portion of the tibial nerve.
Thomas J. Wilson, Andres A. Maldonado, Kimberly K. Amrami, Katrina N. Glazebrook, Michael R. Moynagh and Robert J. Spinner
Hannah E. Gilder, Ross C. Puffer, Mohamad Bydon and Robert J. Spinner
In this study, the authors sought to compare tumors with intradural extension to those remaining in the epidural or paraspinal space with the hypothesis that intradural extension may be a mechanism for seeding of the CSF with malignant cells, thereby resulting in higher rates of CNS metastases and shorter overall survival.
The authors searched the medical record for cases of malignant peripheral nerve sheath tumors (MPNSTs) identified from 1994 to 2017. The charts of the identified patients were then reviewed for tumor location to identify patients with paraspinal malignancy. All patients included in the study had tumor specimens that were reviewed in the surgical pathology department. Paraspinal tumors with intradural extension were identified in the lumbar, sacral, and spinal accessory nerves, and attempts were made to match this cohort to another cohort of patients who had paraspinal tumors of the cranial nerves and lumbar and sacral spinal regions without intradural extension. Further information was collected on all patients with and without intradural extension, including date of diagnosis by pathology specimen review; nerve or nerves of tumor origin; presence, location, and diagnostic date of any CNS metastases; and either the date of death or date of last follow-up.
The authors identified 6 of 179 (3.4%) patients who had intradural tumor extension and compared these patients with 12 patients who harbored paraspinal tumors that did not have intradural extension. All tumors were diagnosed as high-grade MPNSTs according to the surgical pathology findings. Four of 6 (66.7%) patients with intradural extension had documented CNS metastases. The presence of CNS metastases was significantly higher in the intradural group than in the paraspinal group (intradural, 66.7% vs paraspinal, 0%; p < 0.01). Time from diagnosis until death was 11.2 months in the intradural group and approximately 72 months in the paraspinal, extradural cohort.
In patients with intradural extension of paraspinal MPNSTs, significantly higher rates of CNS metastases are seen with a reduced interval of time from diagnosis to metastatic lesion detection. Intradural tumor extension is also a poor prognostic factor for survival, with these patients showing a reduced mean time from diagnosis to death.
Jonathan J. Stone, Nikhil K. Prasad, Pierre Laumonerie, B. Matthew Howe, Kimberly K. Amrami, Jodi M. Carter, Mark E. Jentoft and Robert J. Spinner
Desmoid-type fibromatosis (DTF) presents a therapeutic dilemma. While lacking metastatic potential, it is a locally aggressive tumor with a strong propensity for occurrence near nerve(s) and recurrence following resection. In this study, the authors introduce the association of an occult neuromuscular choristoma (NMC) identified in patients with DTF.
After experiencing a case of DTF found to have an occult NMC, the authors performed a retrospective database review of all other cases of biopsy-proven DTF involving the extremities or limb girdles in patients with available MRI data. Two musculoskeletal radiologists with expertise in peripheral nerve imaging reviewed the MRI studies of the eligible cases for evidence of previously unrecognized NMC.
The initial case of a patient with an occult sciatic NMC is described. The database review yielded 40 patients with DTF—18 (45%) in the upper limb and 22 (55%) in the lower limb. Two cases (5%) had MRI findings of NMC associated with the DTF, one in the proximal sciatic nerve and the other in the proximal tibial and sural nerves.
The coexistence of NMC may be under-recognized in a subset of patients with extremity DTF. This finding poses implications for DTF treatment and the likelihood of recurrence after resection or biopsy. Further study may reveal crucial links between the pathogenesis of NMC and DTF and offer novel therapeutic strategies.
Courtney Pendleton, Allan J. Belzberg, Robert J. Spinner and Alfredo Quinones-Hinojosa
Harvey Cushing is widely regarded as one of the forefathers of neurosurgery, and is primarily associated with his work on intracranial pathology. However, he had a clinical and academic interest in peripheral nerve surgery. Through the courtesy of the Alan Mason Chesney Medical Archives, the surgical records of the Johns Hopkins Hospital from 1896 to 1912 were reviewed. The records of a single patient undergoing brachial plexus exploration and cervical rib resection were selected for detailed review. The operative report and accompanying illustrations demonstrate Cushing’s interest in adding approaches to the pathology of the brachial plexus to his operative armamentarium.
Thomas J. Wilson, Grant M. Kleiber, Ryan M. Nunley, Susan E. Mackinnon and Robert J. Spinner
The sciatic nerve, particularly its peroneal division, is at risk for injury during total hip arthroplasty (THA), especially when a posterior approach is used. The majority of the morbidity results from the loss of peroneal nerve–innervated muscle function. Approximately one-third of patients recover spontaneously. The objectives of this study were to report the outcomes of distal decompression of the peroneal nerve at the fibular tunnel following sciatic nerve injury secondary to THA and to attempt to identify predictors of a positive surgical outcome.
A retrospective study of all patients who underwent peroneal decompression for the indication of sciatic nerve injury following THA at the Mayo Clinic or Washington University School of Medicine in St. Louis was performed. Patients with less than 6 months of postoperative follow-up were excluded. The primary outcome was dorsiflexion strength at latest follow-up. Univariate and multivariate logistic regression analyses were performed to assess the ability of the independent variables to predict a good surgical outcome.
The total included cohort consisted of 37 patients. The median preoperative dorsiflexion grade at the time of peroneal decompression was 0. Dorsiflexion at latest follow-up was Medical Research Council (MRC) ≥ 3 for 24 (65%) patients. Dorsiflexion recovered to MRC ≥ 4− for 15 (41%) patients. In multivariate logistic regression analysis, motor unit potentials in the tibialis anterior (OR 19.84, 95% CI 2.44–364.05; p = 0.004) and in the peroneus longus (OR 8.68, 95% CI 1.05–135.53; p = 0.04) on preoperative electromyography were significant predictors of a good surgical outcome.
After performing peroneal nerve decompression at the fibular tunnel, 65% of the patients in this study recovered dorsiflexion strength of MRC ≥ 3 at latest follow-up, potentially representing a significant improvement over the natural history.
Panagiotis Kerezoudis, Mohammed Ali Alvi, Daniel S. Ubl, Kristine T. Hanson, William E. Krauss, Fredric B. Meyer, Robert J. Spinner, Elizabeth B. Habermann and Mohamad Bydon
Patient-reported outcomes have been increasingly mandated by regulators and payers to evaluate hospital and physician performance. The purpose of this study is to delineate the differences in patient-reported experience of hospital care for cranial and spinal operations.
The authors selected all patients who underwent inpatient, elective cranial or spinal procedures and completed the Hospital Consumer Assessment of Healthcare Providers and Systems (HCAHPS) survey at a single, high-volume, tertiary care institution between October 2012 and September 2015. The association of the surgical procedure and diagnosis with various HCAHPS composite measures, calculated across 9 domains using standard top-box methodology, was investigated. Multivariable logistic regression models were fitted for outcomes that were significant with procedure type and diagnosis group on univariate analysis, adjusting for age, sex, case complexity, overall health rating, and education level.
A total of 1484 patients met criteria and returned an HCAHPS survey. Overall, patients undergoing a cranial procedure gave top-box (most favorable) scores more often in pain management measure (66.3% vs 59.6%, p = 0.01) compared with those undergoing spine surgery. Furthermore, despite better discharge scores (93.1% vs 87.1%, p < 0.001), spinal patients were less likely to report excellent health (7.4% vs 12.7%). Lastly, patients with a primary diagnosis of brain or spinal tumor compared with those with degenerative spinal disease and those with other neurosurgical diagnoses provided top-box scores more often regarding communication with doctors (82.7% vs 76.4% vs 75.2%, p = 0.04), pain management (71.8% vs 60.9% vs 59.1%, p = 0.002), and global rating (90.4% vs 84.0% vs 87.3%, p = 0.02). On multivariable analysis, spinal patients had significantly lower odds of reporting top-box scores in pain management (OR 0.67, 95% CI 0.52–0.85; p = 0.001), staff responsiveness (OR 0.68, 95% CI 0.53–0.87; p = 0.002), and global rating (OR 0.59, 95% CI 0.42–0.82; p = 0.002), and significantly higher odds of top-box scoring in discharge information (OR 2.15, 95% CI 1.45–3.18; p < 0.001) than cranial patients. Similarly, brain tumor cases were associated with significantly higher odds of top-box scoring in communication with doctors (OR 1.46, 95% CI 1.01–2.12; p = 0.04), pain management (OR 1.81, 95% CI 1.29–2.55; p < 0.001), staff responsiveness (OR 1.88, 95% CI 1.33–2.66; p < 0.001), and global rating (OR 2.00, 95% CI 1.26–3.17; p = 0.003) compared with degenerative spine cases.
Significant differences in patient-reported experience with hospital care exist across different cranial and spine surgery patient populations. Overall, spinal patients, particularly those with degenerative spine disease, rated their health and their hospital experience lower relative to cranial patients. Identifying weaker areas of hospital performance in target populations can stimulate quality initiatives that aim to increase the overall hospital score.
Robert J. Spinner, Holly S. Gilmer and Gregory R. Trost
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).
Jonathan J. Stone, Megan C. Kaszuba and Robert J. Spinner
Patients who present with a history of cancer and the new onset of lumbosacral or peripheral neuropathy should be evaluated for the potential of metastasis. Targeted fascicular biopsy can be useful to diagnose atypical lesions within peripheral nerves in patients with major or progressive neurological deficits. In this video, the authors demonstrate the technique of targeted fascicular biopsy of the sciatic nerve in a 63-year-old man with a history of prostate cancer.
The video can be found here: https://youtu.be/PTOX9XxNBDU.
Andrés A. Maldonado, Benjamin M. Howe and Robert J. Spinner
Paralysis of the posterior interosseous nerve (PIN) secondary to compression is a rare clinical condition. Entrapment neuropathy may occur at fibrous bands at the proximal, middle, or distal edge of the supinator. Tumors are a relatively rare but well-known potential cause. The authors present 2 cases of PIN lesions in which compression by a benign lipoma at the level of the elbow resulted in near transection (discontinuity) of the nerve. They hypothesize a mechanism—a “sandwich effect”—by which compression was produced from below by the mass and from above by a fibrous band in the supinator muscle (i.e., the leading edge of the proximal supinator muscle [arcade of Fröhse] in one patient and the distal edge of the supinator muscle in the other). A Grade V Sunderland nerve lesion resulted from the advanced, chronic compression. The authors are unaware of a similar case with such an advanced pathoanatomical finding.
R. Shane Tubbs, Andrés A. Maldonado, Yolanda Stoves, Fabian N. Fries, Rong Li, Marios Loukas, Rod J. Oskouian and Robert J. Spinner
The accessory nerve is frequently repaired or used for nerve transfer. The length of accessory nerve available is often insufficient or marginal (under tension) for allowing direct coaptation during nerve repair or nerve transfer (neurotization), necessitating an interpositional graft. An attractive maneuver would facilitate lengthening of the accessory nerve for direct coaptation. The aim of the present study was to identify an anatomical method for such lengthening.
In 20 adult cadavers, the C-2 or C-3 connections to the accessory nerve were identified medial to the sternocleidomastoid (SCM) muscle and the anatomy of the accessory nerve/cervical nerve fibers within the SCM was documented. The cervical nerve connections were cut. Lengths of the accessory nerve were measured. Samples of the cut C-2 and C-3 nerves were examined using immunohistochemistry.
The anatomy and adjacent neural connections within the SCM are complicated. However, after the accessory nerve was “detethered” from within the SCM and following transection, the additional length of the accessory nerve increased from a mean of 6 cm to a mean of 10.5 cm (increase of 4.5 cm) after cutting the C-2 connections, and from a mean of 6 cm to a mean length of 9 cm (increase of 3.5 cm) after cutting the C-3 connections. The additional length of accessory nerve even allowed direct repair of an infraclavicular target (i.e., the proximal musculocutaneous nerve). The cervical nerve connections were shown not to contain motor fibers.
An additional length of the accessory nerve made available in the posterior cervical triangle can facilitate direct repair or neurotization procedures, thus eliminating the need for an interpositional nerve graft, decreasing the time/distance for regeneration and potentially improving clinical outcomes.