Supraclavicular approach for neonatal brachial plexus palsy

Neonatal brachial plexus palsy describes injury to the brachial plexus in the perinatal period, resulting in motor and sensory deficits of the upper arm. Nerve reconstruction, including graft repair and nerve transfers, can be used to restore function in patients whose injury does not respond to conservative management. Despite the availability of these techniques, 30%-40% of children have lifelong disability, reflecting a 10-fold underutilization of surgery. Here, the authors demonstrate a supraclavicular approach for brachial plexus exploration, as well as a spinal accessory to suprascapular nerve transfer for restoration of shoulder abduction and external rotation. The video can be found here: https://stream.cadmore.media/r10.3171/2022.10.FOCVID22109.

Defining postoperative C5 palsy and recovery: a systematic review

OBJECTIVE

Postoperative C5 palsy (C5P) is a well-recognized and often-delayed complication of cervical spine surgery. Most patients recover within 6 months of onset, but the prognosis of severe cases is poor. The clinical significance and natural history of mild versus severe C5P appear to differ substantially, but palsy severity and recovery have been poorly characterized in the literature.

METHODS

Owing to the varying prognoses and expanding treatment options such as nerve transfer surgery to reconstruct the C5 myotome, this systematic review attempted to describe how C5P severity is classified and how C5P and its recovery are defined, with the aim of proposing a postoperative C5P scale to support clinical decision-making. PubMed was searched for articles in English published since 2000 that offer a clear definition of postoperative C5P or its recovery. Only articles reporting exclusively on C5 palsy for patients undergoing surgery for degenerative disease were included. A single reviewer screened titles and abstracts and reviewed the full text of relevant articles, with consultation as needed from a second reviewer. Data collected included postoperative C5P definitions, classification of C5P severity, and definition and/or classification of C5P recovery. Qualitative analysis was performed.

RESULTS

Full-text reviews were conducted of 98 of 272 articles identified and screened, and 43 met the inclusion criteria. Postoperative C5P was most commonly defined as a reduction in deltoid muscle strength by ≥ 1 grade using manual muscle testing (MMT), with potential biceps involvement also noted by some studies. The few studies that stratified C5P on the basis of severity unanimously characterized severe C5P as MMT grade ≤ 2. Nine studies reported on C5P recovery. Deltoid muscle strength improvement of MMT grade 5 commonly defined complete recovery, with no MMT improvement considered partial recovery.

CONCLUSIONS

This review identified clear discrepancies in the definitions of C5P and its recovery, leading to heterogeneity in its evaluation and management. With the emergence of therapeutic procedures for severe C5P, standardization of the definitions of C5P and its recovery is critical. The authors propose MMT grades of 4, 3, and ≤ 2 to classify C5P as mild, moderate, and severe, respectively, and grades of 5, 4, and 3 to classify recovery as complete, sufficient, and useful, respectively.

Optimal timing of referral for nerve transfer surgery for postoperative C5 palsy

OBJECTIVE

Cervical nerve 5 palsy can occur following surgery for cervical spine pathology. The prognosis of C5 palsy is generally favorable, and most patients recover useful function. However, some patients do not recover useful strength. Nerve transfers are a potential effective treatment of postoperative severe C5 palsy. This study aimed to further delineate the natural history of recovery from postoperative C5 palsy, determine whether lack of recovery at specific time points predicts poor recovery prognosis, and thereby determine a reasonable time point for referral to a complex peripheral nerve specialist.

METHODS

The authors conducted a retrospective review of 72 patients who underwent surgery for cervical spondylosis and stenosis complicated by C5 palsy. Medical Research Council (MRC) motor strength grades were recorded preoperatively; immediately postoperatively; at discharge; and at 2 weeks, 3 months, 6 months, and 12 months postoperatively. Univariate and multivariate logistic regression models were used to identify demographic and clinical risk factors associated with recovery of useful strength after severe C5 palsy.

RESULTS

The mean patient age was 62.5 years, and 36.1% of patients were female. Thirty patients (41.7%) experienced severe C5 palsy with less than antigravity strength (MRC grade 2 or less) at discharge. Twenty-one (70%) of these patients recovered useful strength (MRC grade 3 or greater) at 12 months postoperatively, and 9 patients (30%) did not recover useful strength at 12 months. Of those patients with persistent severe C5 palsy at 3 months postoperatively, 50% recovered useful strength at 12 months. Of those patients with persistent severe C5 palsy at 6 months postoperatively, 25% recovered useful strength at 12 months. No patient with MRC grade 0 or 1 strength at 6 months postoperatively recovered useful strength. A history of diabetes was associated with the occurrence of severe C5 palsy. On multivariate analysis, female sex was associated with recovery of useful strength.

CONCLUSIONS

Most patients with severe C5 palsy recover useful strength in their C5 myotome within 12 months of onset. However, at 3 months postoperatively, patients with persistent severe C5 palsy had only a 50% chance of recovering useful strength by 12 months. Lack of recovery of useful strength at 3 months postoperatively is a reasonable time point for referral to a complex peripheral nerve center to establish care and to determine candidacy for nerve transfer surgery if severe C5 palsy persists.

Quantifying long-term upper-limb activity using wearable motion sensors after nerve reconstruction for neonatal brachial plexus palsy

OBJECTIVE

Standard, physician-elicited clinical assessment tools for the evaluation of function after nerve reconstruction for neonatal brachial plexus palsy (NBPP) do not accurately reflect real-world arm function. Wearable activity monitors allow for the evaluation of patient-initiated, spontaneous arm movement during activities of daily living. In this pilot study, the authors demonstrate the feasibility of using body-worn sensor technology to quantify spontaneous arm movement in children with NBPP 10 years after nerve reconstruction and report the timing and magnitude of recovered arm movement.

METHODS

Eight children with NBPP who underwent brachial plexus reconstruction approximately 10 years prior were recruited to take part in this single-institution prospective pilot study. Per the treatment protocol of the authors' institution, operated patients had severe, nonrecovering nerve function at the time of surgery. The patients were fitted with an activity monitoring device on each of the affected and unaffected arms, which were worn for 7 consecutive days. The duration (VT) and power (VM) with which each arm moved during the patient's normal daily activities were extracted from the accelerometry data and ratios comparing the affected and unaffected arms were calculated. Demographic data and standard physician-elicited clinical measures of upper-extremity function were also collected.

RESULTS

Three children underwent nerve grafting and transfer and 5 children underwent graft repair only. The mean (± SD) active range of motion was 98° ± 53° for shoulder abduction, 130° ± 24° for elbow flexion, and 39° ± 34° for shoulder external rotation. The median Medical Research Council grade was at least 2.5 for all muscle groups. The median Mallet grade was at least 2 for all categories, and 13.5 total. The VT ratio was 0.82 ± 0.08 and the VM ratio was 0.53 ± 0.12.

CONCLUSIONS

Wearable activity monitors such as accelerometers can be used to quantify spontaneous arm movement in children who underwent nerve reconstruction for NBPP at long-term follow-up. These data more accurately reflect complex, goal-oriented movement needed to perform activities of daily living. Notably, despite severe, nonrecovering nerve function early in life, postsurgical NBPP patients use their affected arms more than 80% of the time that they use their unaffected arms, paralleling results in patients with NBPP who recovered spontaneously. These data represent the first long-term, real-world evidence to support brachial plexus reconstruction for patients with NBPP.

Optimizing nerve transfer surgery in tetraplegia: clinical decision making based on innervation patterns in spinal cord injury

OBJECTIVE

Nerve transfers are increasingly being utilized in the treatment of chronic tetraplegia, with increasing literature describing significant improvements in sensorimotor function up to years after injury. However, despite technical advances, clinical outcomes remain heterogenous. Preoperative electrodiagnostic testing is the most direct measure of nerve health and may provide prognostic information that can optimize preoperative patient selection. The objective of this study in patients with spinal cord injury (SCI) was to determine various zones of injury (ZOIs) via electrodiagnostic assessment (EDX) to predict motor outcomes after nerve transfers in tetraplegia.

METHODS

This retrospective review of prospectively collected data included all patients with tetraplegia from cervical SCI who underwent nerve transfer at the authors' institution between 2013 and 2020. Preoperative demographic data, results of EDX, operative details, and postoperative motor outcomes were extracted. EDX was standardized into grades that describe donor and recipient nerves. Five zones of SCI were defined. Motor outcomes were then compared based on various zones of innervation.

RESULTS

Nineteen tetraplegic patients were identified who underwent 52 nerve transfers targeting hand function, and 75% of these nerve transfers were performed more than 1 year postinjury, with a median interval to surgery following SCI of 24 (range 8-142) months. Normal recipient compound muscle action potential and isolated upper motor neuron injury on electromyography (EMG) were associated with greater motor recovery. When nerve transfers were stratified based on donor EMG, greater motor gains were associated with normal than with abnormal donor EMG motor unit recruitment patterns. When nerve transfers were separated based on donor and recipient nerves, normal flexor donors were more crucial than normal extensor donors in powering their respective flexor recipients.

CONCLUSIONS

This study elucidates the relationship of the preoperative innervation zones in SCI patients to final motor outcomes. EDX studies can be used to tailor surgical therapies for nerve transfers in patients with tetraplegia. The authors propose an algorithm for optimizing nerve transfer strategies in tetraplegia, whereby understanding the ZOI and grade of the donor/recipient nerve is critical to predicting motor outcomes.

MRI evaluation of nerve root avulsion in neonatal brachial plexus palsy: understanding the presence of isolated dorsal/ventral rootlet disruption

OBJECTIVE

The evaluation, treatment, and prognosis of neonatal brachial plexus palsy (NBPP) continues to have many areas of debate, including the use of ancillary testing. Given the continued improvement in imaging, it is important to revisit its utility. Nerve root avulsions have historically been identified by the presence of pseudomeningoceles or visible ruptures. This "all-or-none" definition of nerve root avulsions has many implications for the understanding and management of NBPP, especially as characterization of the proximal nerve root as a potential donor remains critical. This study examined the ability of high-resolution MRI to more specifically define the anatomy of nerve root avulsions by individually examining the ventral and dorsal rootlets as they exit the spinal cord.

METHODS

This is a retrospective review of patients who had undergone brachial plexus protocol MRI for clinical evaluation of NBPP at a single institution. Each MR image was independently reviewed by a board-certified neuroradiologist, who was blinded to both established diagnosis/surgical findings and laterality. Each dorsal and ventral nerve rootlet bilaterally from C5 to T1 was evaluated from the spinal cord to its exit in the neuroforamen. Each rootlet was classified as avulsed, intact, or undeterminable.

RESULTS

Sixty infants underwent brachial plexus protocol MRI from 2010 to 2018. All infants were included in this study. Six hundred individual rootlets were analyzed. There were 49 avulsed nerve rootlets in this cohort. Twenty-nine (59%) combined dorsal/ventral avulsions involved both the ventral and dorsal rootlets, and 20 (41%) were either isolated ventral or isolated dorsal rootlet avulsions. Of the isolated avulsion injuries, 13 (65%) were dorsal only, meaning that the motor rootlets were intact.

CONCLUSIONS

A closer look at nerve root avulsions with MRI demonstrates a significant prevalence (approximately 41%) of isolated dorsal or ventral nerve rootlet disruptions. This finding implies that nerve roots previously labeled as "avulsed" but with only isolated dorsal (sensory) rootlet avulsion can yet provide donor fascicles in reconstruction strategies. A majority (99%) of the rootlets can be clearly visualized with MRI. These findings may significantly impact the clinical understanding of neonatal brachial plexus injury and its treatment.

Analysis of the effect of intraoperative neuromonitoring during resection of benign nerve sheath tumors on gross-total resection and neurological complications

OBJECTIVE

The aim of this study was to examine the role of intraoperative neuromonitoring (IONM) during resection of benign peripheral nerve sheath tumors in achieving gross-total resection (GTR) and in reducing postoperative neurological complications.

METHODS

Data from consecutive adult patients who underwent resection of a benign peripheral nerve sheath tumor at 7 participating institutions were combined. Propensity score matching was used to balance covariates. The primary outcomes of interest were the association between IONM and GTR and the association of IONM and the development of a permanent postoperative neurological complication. The secondary outcomes of interest were the association between IONM and GTR and the association between IONM and the development of a permanent postoperative neurological complication in the subgroup of patients with tumors involving a motor or mixed nerve. Univariate and multivariate logistic regression were then performed on the propensity score-matched samples to assess the ability of the independent variables to predict the outcomes of interest.

RESULTS

A total of 337 patients who underwent resection of benign nerve sheath tumors were included. In multivariate analysis, the use of IONM (OR 0.460, 95% CI 0.199-0.978; p = 0.047) was a significant negative predictor of GTR, whereas none of the variables, including IONM, were associated with the occurrence of a permanent postoperative neurological complication. Within the subgroup of motor/mixed nerve tumors, in the multivariate analysis, IONM (OR 0.263, 95% CI 0.096-0.723; p = 0.010) was a significant negative predictor of a GTR, whereas IONM (OR 3.800, 95% CI 1.925-7.502; p < 0.001) was a significant positive predictor of a permanent postoperative motor deficit.

CONCLUSIONS

Overall, 12% of the cohort had a permanent neurological complication, with new or worsened paresthesias most common, followed by pain and then weakness. The authors found that formal IONM was associated with a reduced likelihood of GTR and had no association with neurological complications. The authors believe that these data argue against IONM being considered standard of care but do not believe that these data should be used to universally argue against IONM during resection of benign nerve sheath tumors.

Nerve graft versus nerve transfer for neonatal brachial plexus: shoulder outcomes

OBJECTIVE

The decision-making in neonatal brachial plexus palsy (NBPP) treatment continues to have many areas in need of clarification. Graft repair was the gold standard until the introduction of nerve transfer strategies. Currently, there is conflicting evidence regarding outcomes in patients with nerve grafts versus nerve transfers in relation to shoulder function. The objective of this study was to further define the outcomes for reconstruction strategies in NBPP with a specific focus on the shoulder.

METHODS

A cohort of patients with NBPP and surgical repairs from a single center were reviewed. Demographic and standard clinical data, including imaging and electrodiagnostics, were gathered from a clinical database. Clinical data from physical therapy evaluations, including active and passive range of motion, were examined. Statistical analysis was performed on the available data.

RESULTS

Forty-five patients met the inclusion criteria for this study, 19 with graft repair and 26 with nerve transfers. There were no significant differences in demographics between the two groups. Understandably, there were no patients in the nerve grafting group with preganglionic lesions, resulting in a difference in lesion type between the cohorts. There were no differences in preoperative shoulder function between the cohorts. Both groups reached statistically significant improvements in shoulder flexion and shoulder abduction. The nerve transfer group experienced a significant improvement in shoulder external rotation, from -78° to -28° (p = 0.0001), whereas a significant difference was not reached in the graft group. When compared between groups, there appeared to be a trend favoring nerve transfer in shoulder external rotation, with the graft patients improving by 17° and the transfer patients improving by 49° (p = 0.07).

CONCLUSIONS

In NBPP, patients with shoulder weakness experience statistically significant improvements in shoulder flexion and abduction after graft repair or nerve transfer, and patients with nerve transfers additionally experience significant improvement in external rotation. With regard to shoulder external rotation, there appear to be some data supporting the use of nerve transfers.

The Presence and Persistence of Unrealistic Expectations in Patients Undergoing Nerve Surgery

BACKGROUND

Unrealistic expectations of the outcomes of peripheral nerve surgery reduce patient satisfaction. Most clinicians can recall patients with unrealistic expectations despite verbal preoperative education.

OBJECTIVE

To assess patients’ baseline level of understanding regarding nerve surgery and appropriate expectations. Additionally, we tested the effect of a written, preoperative educational handout on the patients’ retention of knowledge.

METHODS

This cross-sectional survey recruited patients scheduled to undergo peripheral nerve surgery at a single institution in 2016 to 2017. During the preoperative visit, a specialized nurse practitioner reviewed perioperative protocols, risks and benefits of the surgery, and postoperative care. Patients immediately completed a survey to assess their preoperative understanding of the verbally reviewed information. During the same visit, an additional written handout was given to patients in a randomized fashion. At their first postoperative visit, all patients completed the survey again.

RESULTS

A total of 60 patients (mean age 52 yr) were enrolled of which 62% were male. Immediately following verbal instruction, 31% of patients had erroneous (unrealistic) expectations regarding pain, 30% had erroneous expectations regarding postoperative motor outcome, and 41% had erroneous expectations regarding the timing of postoperative recovery. There was no significant difference between patients who received the written handout vs those who did not, on retesting in the postoperative period.

CONCLUSION

Patients undergoing peripheral nerve procedures demonstrated a high baseline level of unrealistic expectations despite standard in-person verbal counseling by specialty providers. A written handout did not have clear benefit in the retention of preoperative surgical teaching. Further investigation into more effective preoperative patient counseling is needed.

Nerve transfers in the upper extremity following cervical spinal cord injury. Part 1: Systematic review of the literature

OBJECTIVE

Patients with cervical spinal cord injury (SCI)/tetraplegia consistently rank restoring arm and hand function as their top functional priority to improve quality of life. Motor nerve transfers traditionally used to treat peripheral nerve injuries are increasingly being used to treat patients with cervical SCIs. In this study, the authors performed a systematic review summarizing the published literature on nerve transfers to restore upper-extremity function in tetraplegia.

METHODS

A systematic literature search was conducted using Ovid MEDLINE 1946-, Embase 1947-, Scopus 1960-, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, and clinicaltrials.gov to identify relevant literature published through January 2019. The authors included studies that provided original patient-level data and extracted information on clinical characteristics, operative details, and strength outcomes after nerve transfer procedures. Critical review and synthesis of the articles were performed.

RESULTS

Twenty-two unique studies, reporting on 158 nerve transfers in 118 upper limbs of 92 patients (87 males, 94.6%) were included in the systematic review. The mean duration from SCI to nerve transfer surgery was 18.7 months (range 4 months-13 years) and mean postoperative follow-up duration was 19.5 months (range 1 month-4 years). The main goals of reinnervation were the restoration of thumb and finger flexion, elbow extension, and wrist and finger extension. Significant heterogeneity in transfer strategy and postoperative outcomes were noted among the reports. All but one case report demonstrated recovery of at least Medical Research Council grade 3/5 strength in recipient muscle groups; however, there was greater variation in the results of larger case series. The best, most consistent outcomes were demonstrated for restoration of wrist/finger extension and elbow extension.

CONCLUSIONS

Motor nerve transfers are a promising treatment option to restore upper-extremity function after SCI. Flexor reinnervation strategies show variable treatment effect sizes; however, extensor reinnervation may provide more consistent, meaningful recovery. Despite numerous published case reports describing good patient outcomes with nerve transfers, there remains a paucity in the literature regarding optimal timing and long-term clinical outcomes with these procedures.

Nerve transfers in the upper extremity following cervical spinal cord injury. Part 2: Preliminary results of a prospective clinical trial

OBJECTIVE

Patients with cervical spinal cord injury (SCI)/tetraplegia consistently rank restoring arm and hand function as their top functional priority to improve quality of life. Motor nerve transfers traditionally used to treat peripheral nerve injuries are increasingly used to treat patients with cervical SCIs. In this article, the authors present early results of a prospective clinical trial using nerve transfers to restore upper-extremity function in tetraplegia.

METHODS

Participants with American Spinal Injury Association (ASIA) grade A-C cervical SCI/tetraplegia were prospectively enrolled at a single institution, and nerve transfer(s) was performed to improve upper-extremity function. Functional recovery and strength outcomes were independently assessed and prospectively tracked.

RESULTS

Seventeen participants (94.1% males) with a median age of 28.4 years (range 18.2-76.3 years) who underwent nerve transfers at a median of 18.2 months (range 5.2-130.8 months) after injury were included in the analysis. Preoperative SCI levels ranged from C2 to C7, most commonly at C4 (35.3%). The median postoperative follow-up duration was 24.9 months (range 12.0-29.1 months). Patients who underwent transfers to median nerve motor branches and completed 18- and 24-month follow-ups achieved finger flexion strength Medical Research Council (MRC) grade ≥ 3/5 in 4 of 15 (26.7%) and 3 of 12 (25.0%) treated upper limbs, respectively. Similarly, patients achieved MRC grade ≥ 3/5 wrist flexion strength in 5 of 15 (33.3%) and 3 of 12 (25.0%) upper limbs. Among patients who underwent transfers to the posterior interosseous nerve (PIN) for wrist/finger extension, MRC grade ≥ 3/5 strength was demonstrated in 5 of 9 (55.6%) and 4 of 7 (57.1%) upper limbs 18 and 24 months postoperatively, respectively. Similarly, grade ≥ 3/5 strength was demonstrated in 5 of 9 (55.6%) and 4 of 7 (57.1%) cases for thumb extension. No meaningful donor site deficits were observed. Patients reported significant postoperative improvements from baseline on upper-extremity-specific self-reported outcome measures.

CONCLUSIONS

Motor nerve transfers are a promising treatment option to restore upper-extremity function after SCI. In the authors' experience, nerve transfers for the reinnervation of hand and finger flexors showed variable functional recovery; however, transfers for the reinnervation of arm, hand, and finger extensors showed a more consistent and meaningful return of strength and function.

Comparative accuracies of electrodiagnostic and imaging studies in neonatal brachial plexus palsy

OBJECTIVEThe incorporation of ancillary testing in the preoperative setting for patients with neonatal brachial plexus palsy (NBPP) remains controversial, but the recommendation for early nerve reconstruction when a baby has a preganglionic lesion at the lower nerve roots is generally accepted. At some specialty centers, nerve surgeons use preoperative electrodiagnostic testing (EDX) and imaging to aid in lesion localization and the preoperative planning of the nerve reconstruction. EDX and imaging have been evaluated for their abilities to detect pre- and postganglionic lesions, but their accuracies have never been compared directly in the same set of patients. The aim of the present study was to evaluate the accuracy of imaging and EDX in an NBPP population.METHODSA retrospective review was conducted of 54 patients with operative NBPP seen between 2007 and 2017. The patients underwent EDX and imaging: EDX was performed, and the results were reviewed by board-certified electrodiagnosticians, and imaging was reviewed by board-certified neuroradiologists. The gold standard was considered to be the findings at surgical exploration. Descriptive and analytical statistics were utilized to compare the accuracies of imaging and EDX.RESULTSThe mean age at surgery was 6.94 mos (± 4 mos). Fifteen patients (28%) were Narakas grade I-II, and 39 (72%) were Narakas grade III-IV. For all nerve roots, the overall accuracy of detecting preganglionic lesions was 74% for EDX and 69% for imaging. The overall sensitivity of detecting preganglionic lesions by EDX was 31%, but the specificity was 90%. The overall sensitivity of detecting preganglionic lesions by imaging was 66%, and the overall specificity was 70%. However, at C8, EDX was 37.5% sensitive and 87.5% specific, whereas imaging was 67.7% sensitive but only 29.4% specific.CONCLUSIONSEDX outperformed imaging with regard to specificity and accuracy of identifying preganglionic injuries. This finding is especially relevant in the lower nerve roots, given that lower plexus preganglionic lesions are an accepted indication for early intervention.

Effect of fascicle composition on ulnar to musculocutaneous nerve transfer (Oberlin transfer) in neonatal brachial plexus palsy

OBJECTIVE Neonatal brachial plexus palsy (NBPP) continues to be a problematic occurrence impacting approximately 1.5 per 1000 live births in the United States, with 10%-40% of these infants experiencing permanent disability. These children lose elbow flexion, and one surgical option for recovering it is the Oberlin transfer. Published data support the use of the ulnar nerve fascicle that innervates the flexor carpi ulnaris as the donor nerve in adults, but no analogous published data exist for infants. This study investigated the association of ulnar nerve fascicle choice with functional elbow flexion outcome in NBPP. METHODS The authors conducted a retrospective study of 13 cases in which infants underwent ulnar to musculocutaneous nerve transfer for NBPP at a single institution. They collected data on patient demographics, clinical characteristics, active range of motion (AROM), and intraoperative neuromonitoring (IONM) (using 4 ulnar nerve index muscles). Standard statistical analysis compared pre- and postoperative motor function improvement between specific fascicle transfer (1-2 muscles for either wrist flexion or hand intrinsics) and nonspecific fascicle transfer (> 2 muscles for wrist flexion and hand intrinsics) groups. RESULTS The patients' average age at initial clinic visit was 2.9 months, and their average age at surgical intervention was 7.4 months. All NBPPs were unilateral; the majority of patients were female (61%), were Caucasian (69%), had right-sided NBPP (61%), and had Narakas grade I or II injuries (54%). IONM recordings for the fascicular dissection revealed a donor fascicle with nonspecific innervation in 6 (46%) infants and specific innervation in the remaining 7 (54%) patients. At 6-month follow-up, the AROM improvement in elbow flexion in adduction was 38° in the specific fascicle transfer group versus 36° in the nonspecific fascicle transfer group, with no statistically significant difference (p = 0.93). CONCLUSIONS Both specific and nonspecific fascicle transfers led to functional recovery, but that the composition of the donor fascicle had no impact on early outcomes. In young infants, ulnar nerve fascicular dissection places the ulnar nerve at risk for iatrogenic damage. The data from this study suggest that the use of any motor fascicle, specific or nonspecific, produces similar results and that the Oberlin transfer can be performed with less intrafascicular dissection, less time of surgical exposure, and less potential for donor site morbidity.

Oberlin transfer compared with nerve grafting for improving early supination in neonatal brachial plexus palsy

OBJECTIVE The use of nerve transfers versus nerve grafting for neonatal brachial plexus palsy (NBPP) remains controversial. In adult brachial plexus injury, transfer of an ulnar fascicle to the biceps branch of the musculocutaneous nerve (Oberlin transfer) is reportedly superior to nerve grafting for restoration of elbow flexion. In pediatric patients with NBPP, recovery of elbow flexion and forearm supination is an indicator of resolved NBPP. Currently, limited evidence exists of outcomes for flexion and supination when comparing nerve transfer and nerve grafting for NBPP. Therefore, the authors compared 1-year postoperative outcomes for infants with NBPP who underwent Oberlin transfer versus nerve grafting. METHODS This retrospective cohort study reviewed patients with NBPP who underwent Oberlin transfer (n = 19) and nerve grafting (n = 31) at a single institution between 2005 and 2015. A single surgeon conducted intraoperative exploration of the brachial plexus and determined the surgical nerve reconstruction strategy undertaken. Active range of motion was evaluated preoperatively and postoperatively at 1 year. RESULTS No significant difference between treatment groups was observed with respect to the mean change (pre- to postoperatively) in elbow flexion in adduction and abduction and biceps strength. The Oberlin transfer group gained significantly more supination (100° vs 19°; p < 0.0001). Forearm pronation was maintained at 90° in the Oberlin transfer group whereas it was slightly improved in the grafting group (0° vs 32°; p = 0.02). Shoulder, wrist, and hand functions were comparable between treatment groups. CONCLUSIONS The preliminary data from this study demonstrate that the Oberlin transfer confers an advantageous early recovery of forearm supination over grafting, with equivalent elbow flexion recovery. Further studies that monitor real-world arm usage will provide more insight into the most appropriate surgical strategy for NBPP.

Imaging Nerve Pathology of the Knee: Magnetic Resonance Imaging and Ultrasound

Peripheral neuropathies are not uncommon, and the diagnostic evaluation includes a clinical assessment and electrophysiologic studies as well as diagnostic imaging. Magnetic resonance imaging (MRI) and high-resolution ultrasound (HRUS) are of special importance in providing the surgeon with information in the context of nerve trauma, entrapment, and nerve involvement by tumors. Peripheral neuropathy about the knee can occur in the context of associated knee pathology such as trauma, as part of a systemic disease, or as an isolated finding. In this review, we discuss the role of MRI and HRUS in the evaluation of peripheral neuropathy and present imaging examples of peripheral neuropathy involving the knee.

Pilot study of intraoperative ultrasound-guided instrument placement in nerve transection surgery for peripheral nerve pain syndromes

Surgical transection of sensory nerves in the treatment of intractable neuropathic pain is a commonly performed procedure. At times these cases can be particularly challenging when encountering obese patients, when targeting deeper nerves or those with a variable branching pattern, or in the case of repeat operations. In this case series, the authors describe their experience with ultrasound-guided surgical instrument placement during transection of a saphenous nerve in the region of prior vascular surgery in 1 patient and in the lateral femoral cutaneous nerve in 2 obese patients. The authors also describe this novel technique and provide pilot data that suggests ultrasound-assisted surgery may allow for complex cases to be completed in an expedited fashion through smaller incisions.

Peripartum and neonatal factors associated with the persistence of neonatal brachial plexus palsy at 1 year: a review of 382 cases

OBJECTIVE Neonatal brachial plexus palsy (NBPP) occurs due to the stretching of the nerves of the brachial plexus before, during, or after delivery. NBPP can resolve spontaneously or become persistent. To determine if nerve surgery is indicated, predicting recovery is necessary but difficult. Historical attempts explored the association of recovery with only clinical and electrodiagnostic examinations. However, no data exist regarding the neonatal and peripartum factors associated with NBPP persistence. METHODS This retrospective cohort study involved all NBPP patients at the University of Michigan between 2005 and 2015. Peripartum and neonatal factors were assessed for their association with persistent NBPP at 1 year, as defined as the presence of musculoskeletal contractures or an active range of motion that deviated from normal by > 10° (shoulder, elbow, hand, and finger ranges of motion were recorded). Standard statistical methods were used. RESULTS Of 382 children with NBPP, 85% had persistent NBPP at 1 year. A wide range of neonatal and peripartum factors was explored. We found that cephalic presentation, induction or augmentation of labor, birth weight > 9 lbs, and the presence of Horner syndrome all significantly increased the odds of persistence at 1 year, while cesarean delivery and Narakas Grade I to II injury significantly reduced the odds of persistence. CONCLUSIONS Peripartum/neonatal factors were identified that significantly altered the odds of having persistent NBPP at 1 year. Combining these peripartum/neonatal factors with previously published clinical examination findings associated with persistence should allow the development of a prediction algorithm. The implementation of this algorithm may allow the earlier recognition of those cases likely to persist and thus enable earlier intervention, which may improve surgical outcomes.

The anconeus epitrochlearis muscle may protect against the development of cubital tunnel syndrome: a preliminary study

OBJECTIVE The authors hypothesized that when the anatomical variant of an anconeus epitrochlearis is present, the risk of developing cubital tunnel syndrome would be reduced by replacing the normal roof of the cubital tunnel (Osborne's ligament) with a more forgiving muscular structure, the anconeus epitrochlearis. The authors further hypothesized that when the presence of an anconeus epitrochlearis contributes to ulnar neuropathy, it would be secondary to muscular hypertrophy, thereby making it more likely to occur in the dominant arm. Therefore, the goal of the present study was to evaluate these hypotheses. METHODS This retrospective cohort study was performed by reviewing the records of all adult patients who underwent operative intervention for cubital tunnel syndrome between 2005 and 2014 as the experimental group and all asymptomatic patients in the medical literature who were part of a series reporting the prevalence of an anconeus epitrochlearis as the control group. The primary outcome of interest was the presence of an anconeus epitrochlearis in asymptomatic individuals versus patients with cubital tunnel syndrome. RESULTS During the study period, 168 patients underwent decompression of the ulnar nerve for cubital tunnel syndrome, and an anconeus epitrochlearis was found at surgery in 9 (5.4%) patients. The control group consisted of 634 asymptomatic patients from the medical literature, and an anconeus epitrochlearis was present in 98 (15.5%) of these patients. An anconeus epitrochlearis was present significantly less frequently in the symptomatic patients than in asymptomatic individuals (p < 0.001). Among patients undergoing surgical decompression, an anconeus epitrochlearis was associated with symptoms in the dominant arm (p = 0.037). CONCLUSIONS The authors found that an anconeus epitrochlearis was present significantly less often in patients with cubital tunnel syndrome than in asymptomatic controls. The mechanism of protection may be that this muscle decreases the rigidity of the entrance into the cubital tunnel. When an anconeus epitrochlearis does contribute to cubital tunnel syndrome, it is significantly more likely to occur in the dominant arm, possibly due to repetitive use and hypertrophy of the anconeus epitrochlearis. The presence of an anconeus epitrochlearis may be protective against the development of cubital tunnel syndrome, although this is a preliminary finding.

Evaluation and management of fibrofatty tumors of the extremities: case report

Patients presenting with enlarging fibrofatty masses in the extremities pose an interesting dilemma to clinicians, as the differential diagnosis in such cases ranges from benign to malignant, and from lesions optimally managed operatively to those managed nonoperatively. The differential diagnosis includes benign lipoma, liposarcoma, lipoblastoma, and fibrolipomatous hamartoma (lipomatosis) of the nerves. The authors present the case of a 14-year-old girl with an enlarging fibrofatty mass of the forearm, initially thought, based on diagnostic imaging, to be a fibrolipomatous hamartoma of the median nerve, but found to be a lipoblastoma without direct nerve involvement based on histopathological examination of the operative specimen. This case serves to illustrate the diagnostic predicament that can exist with such masses. The authors advocate the need to establish a tissue diagnosis while having a contingency plan for each of the diagnostic possibilities because the management of each lesion is markedly different. In this report, the authors consider the differential diagnosis of fibrofatty masses of the extremities that the peripheral nerve surgeon may encounter, and they highlight the significant differences in management strategies for each possible diagnosis.

Patient misconceptions concerning lumbar spondylosis diagnosis and treatment

OBJECT

Patient outcome measures are becoming increasingly important in the evaluation of health care quality and physician performance. Of the many novel measures currently being explored, patient satisfaction and other subjective measures of patient experience are among the most heavily weighted. However, these subjective measures are strongly influenced by a number of factors, including patient demographics, level of understanding of the disorder and its treatment, and patient expectations. In the present study, patients referred to a neurosurgery clinic for degenerative spinal disorders were surveyed to determine their understanding of lumbar spondylosis diagnosis and treatment.

METHODS

A multiple-choice, 6-question survey was distributed to all patients referred to a general neurosurgical spine clinic at a tertiary care center over a period of 11 months as a quality improvement initiative to assist the provider with individualized patient counseling. The survey consisted of questions designed to assess patient understanding of the role of radiological imaging in the diagnosis and treatment of low-back and leg pain, and patient perception of the indications for surgical compared with conservative management. Demographic data were also collected.

RESULTS

A total of 121 surveys were included in the analysis. More than 50% of the patients indicated that they would undergo spine surgery based on abnormalities found on MRI, even without symptoms; more than 40% of patients indicated the same for plain radiographs. Similarly, a large proportion of patients (33%) believed that back surgery was more effective than physical therapy in the treatment of back pain without leg pain. Nearly one-fifth of the survey group (17%) also believed that back injections were riskier than back surgery. There were no significant differences in survey responses among patients with a previous history of spine surgery compared with those without previous spine surgery.

CONCLUSIONS

These results show that a surprisingly high percentage of patients have misconceptions regarding the diagnosis and treatment of lumbar spondylosis, and that these misconceptions persist in patients with a history of spine surgery. Specifically, patients overemphasize the value of radiological studies and have mixed perceptions of the relative risk and effectiveness of surgical intervention compared with more conservative management. These misconceptions have the potential to alter patient expectations and decrease satisfaction, which could negatively impact patient outcomes and subjective valuations of physician performance. While these results are preliminary, they highlight a need for improved communication and patient education during surgical consultation for lumbar spondylosis.

Ultrasonography for neonatal brachial plexus palsy

Ultrasonography has previously been reported for use in the evaluation of compressive or traumatic peripheral nerve pathology and for its utility in preoperative mapping. However, these studies were not performed in infants, and they were not focused on the brachial plexus. The authors report a case in which ultrasonography was used to improve operative management of neonatal brachial plexus palsy (NBPP). An infant boy was born at term, complicated by right-sided shoulder dystocia. Initial clinical evaluation revealed proximal arm weakness consistent with an upper trunk injury. Unlike MRI or CT myelography that focus on proximal nerve roots, ultrasonography of the brachial plexus in the supraclavicular fossa was able to demonstrate a small neuroma involving the upper trunk (C-5 and C-6) and no asymmetry in movement of the diaphragm or in the appearance of the rhomboid muscle when compared with the unaffected side. However, the supra- and infraspinatus muscles were significantly asymmetrical and atrophied on the affected side. Importantly, ultrasound examination of the shoulder revealed posterior glenohumeral laxity. Instead of pursuing the primary nerve reconstruction first, timely treatment of the shoulder subluxation prevented formation of joint dysplasia and formation of a false glenoid, which is a common sequela of this condition. Because the muscles innervated by proximal branches of the cervical nerve roots/trunks were radiographically normal, subsequent nerve transfers were performed and good functional results were achieved. The authors believe this to be the first report describing the utility of ultrasonography in the surgical treatment planning in a case of NBPP. Noninvasive imaging, in addition to thorough history and physical examination, reduces the intraoperative time required to determine the extent and severity of nerve injury by allowing improved preoperative planning of the surgical strategy. Inclusion of ultrasonography as a preoperative modality may yield improved outcomes for children with NBPP.

Lack of physician-patient communication as a key factor associated with malpractice litigation in neonatal brachial plexus palsy

OBJECT

Perinatal disorders are prone to malpractice litigation. Neonatal brachial plexus palsy (NBPP) results from stretching the nerves in the perinatal period and may lead to paresis or paralysis and sensory loss in the affected arm. Little is known about the key factors associated with malpractice litigation by families of patients with NBPP and whether these factors reflect the practice environment or are inherent to the condition. In this study, the authors documented the percentage of families of NBPP patients at a specialty center that had filed a malpractice suit and described the key factors associated with that pursuit of legal action.

METHODS

The families/caregivers of 51 patients with NBPP who had presented to the University of Michigan Interdisciplinary Brachial Plexus Program participated in this study. A qualitative research design was applied using both a questionnaire to examine psychosocial factors and a dynamic tool to measure health outcomes from the patient perspective via parent proxy (Patient-Reported Outcomes Measurement Information System [PROMIS] assessment instruments). Statistical analysis included the Fisher exact test, chi-square test, and Student t-test. The study protocol was approved by the University of Michigan institutional review board.

RESULTS

Forty-seven percent of the families pursued malpractice litigation. In comparing patient families that had pursued legal action with those that had not, significant differences were revealed in the perception that the sustained birth injury was unnecessary (p = 0.002), the information received in the perinatal period was inadequate (p = 0.003), family concerns were ignored in the perinatal period (p = 0.005), and family concerns were not adequately addressed (p < 0.001). Sixty-six percent of the families received external advice to pursue legal action. The PROMIS survey revealed significant group differences in depressive symptoms (p = 0.008), fatigue (p = 0.02), pain (p = 0.01), and anger (p = 0.004). In contrast, the extent of NBPP was not associated with malpractice litigation (p = 0.18). Age, sex, and race were not significantly different between litigation and nonlitigation groups.

CONCLUSIONS

Physician-controllable factors, such as communication in the perinatal period, are associated with malpractice litigation in NBPP. The perceived level of global disability may affect the pursuit of malpractice litigation, whereas the isolated extent of nerve root involvement and/or upper extremity dysfunction are not significant factors in pursuing litigation. Identifying and ameliorating these factors within the practice environment may decrease the animosity between families and health care providers and improve overall outcome for patients with NBPP.

An outcome study for ulnar neuropathy at the elbow: a multicenter study by the surgery for ulnar nerve (SUN) study group

BACKGROUND

Many instruments have been developed to measure upper extremity disability, but few have been applied to ulnar neuropathy at the elbow (UNE).

OBJECTIVE

We measured patient outcomes following ulnar nerve decompression to (1) identify the most appropriate outcomes tools for UNE and (2) to describe outcomes following ulnar nerve decompression.

METHODS

Thirty-nine patients from 5 centers were followed prospectively after nerve decompression. Outcomes were measured preoperatively and at 6 weeks, 3 months, 6 months, and 12 months postoperatively. Each patient completed the Michigan Hand Questionnaire (MHQ), Carpal Tunnel Questionnaire (CTQ), and Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaires. Grip, key-pinch strength, Semmes-Weinstein monofilament, and 2-point discrimination were measured. Construct validity was calculated by using Spearman correlation coefficients between questionnaire scores and physical and sensory measures. Responsiveness was assessed by standardized response means.

RESULTS

Key-pinch (P = .008) and Semmes-Weinstein monofilament testing of the ulnar ring (P < .001) and small finger (radial: P = .004; ulnar: P < .001) improved following decompression. Two-point discrimination improved significantly across the radial (P = .009) and ulnar (P = .007) small finger. Improved symptoms and function were noted by the CTQ (preoperative CTQ symptom score 2.73 vs 1.90 postoperatively, P < .001), DASH (P < .001), and MHQ: function (P < .001), activities of daily living (P = .003), work (P = .006), pain (P < .001), and satisfaction (P < .001). All surveys demonstrated strong construct validity, defined by correlation with functional outcomes, but MHQ and CTQ symptom instruments demonstrated the highest responsiveness.

CONCLUSION

Patient-reported outcomes improve following ulnar nerve decompression, including pain, function, and satisfaction. The MHQ and CTQ are more responsive than the DASH for isolated UNE treated with decompression.

High-resolution MRI evaluation of neonatal brachial plexus palsy: A promising alternative to traditional CT myelography

BACKGROUND AND PURPOSE

Despite recent improvements in perinatal care, the incidence of neonatal brachial plexus palsy remains relatively common. CT myelography is currently considered to be the optimal imaging technique for evaluating nerve root integrity. Recent improvements in MR imaging techniques have made it an attractive alternative to evaluate nerve root avulsions (preganglionic injuries). We aim to demonstrate utility of MR imaging in the evaluation of normal and avulsed spinal nerve roots.

MATERIALS AND METHODS

All study patients with clinically diagnosed neonatal brachial plexus palsy underwent MR imaging by use of a high-resolution, heavily T2-weighted (driven equilibrium) sequence. MR imaging findings were reviewed for presence of nerve root avulsion from C5-T1 and for presence of pseudomeningocele. The intraoperative findings were reviewed and compared with the preoperative MR imaging findings.

RESULTS

Thirteen patients (9 male, 4 female) underwent MR imaging; 6 patients underwent nerve reconstruction surgery, during which a total of 19 nerve roots were evaluated. Eight avulsions were noted at surgery and in the remainder, the nerve injury was more distal (rupture/postganglionic injury). Six of the 8 nerve root avulsions identified at surgery were at C5-6 level, whereas 1 nerve root avulsion was identified at C7 and C8 levels, respectively. The overall sensitivity and specificity of MR imaging for nerve root avulsions was 75% and 82%, respectively.

CONCLUSIONS

Our preliminary results demonstrate that high-resolution MR imaging offers an excellent alternative to CT myelography for the evaluation of neonatal brachial plexus palsy with similar sensitivity compared with CT myelography.

A systematic review of evaluation methods for neonatal brachial plexus palsy: a review

OBJECT

Neonatal brachial plexus palsy (NBPP) affects 0.4-2.6 newborns per 1000 live births in the US. Many infants recover spontaneously, but for those without spontaneous recovery, nerve and/or secondary musculoskeletal reconstruction can restore function to the affected arm. This condition not only manifests in a paretic/paralyzed arm, but also affects the overall health and psychosocial condition of the children and their parents. Currently, measurement instruments for NBPP focus primarily on physical ability, with limited information regarding the effect of the disablement on activities of daily living and the child's psychosocial well-being. It is also difficult to assess and compare overall treatment efficacy among medical (conservative) or surgical management strategies without consistent use of evaluation instruments. The purpose of this study is to review the reported measurement evaluation methods for NBPP in an attempt to provide recommendations for future measurement usage and development.

METHODS

The authors systematically reviewed the literature published between January 1980 and February 2012 using multiple databases to search the keywords "brachial plexus" and "obstetric" or "pediatrics" or "neonatal" or "congenital." Original articles with primary patient outcomes were included in the data summary. Four types of evaluation methods (classification, diagnostics, physical assessment, and functional outcome) were distinguished among treatment management groups. Descriptive statistics and 1-way ANOVA were applied to compare the data summaries among specific groups.

RESULTS

Of 2836 articles initially identified, 307 were included in the analysis, with 198 articles (9646 patients) reporting results after surgical treatment, 70 articles (4434 patients) reporting results after medical treatment, and 39 articles (4247 patients) reporting results after combined surgical and medical treatment. Among medical practitioners who treat NBPP, there was equivalence in usage of classification, diagnostic, and physical assessment tools (that focused on the Body Function and Structures measure of the International Classification of Functioning, Disability, and Health [ICF]). However, there was discordance in the functional outcome measures that focus on ICF levels of Activity and Participation. Of the 126 reported evaluation methods, only a few (the Active Movement Scale, Toronto Scale Score, Mallet Scale, Assisting Hand Assessment, and Pediatric Outcomes Data Collection Instrument) are specifically validated for evaluating the NBPP population.

CONCLUSIONS

In this review, the authors demonstrate disparities in the use of NBPP evaluation instruments in the current literature. Additionally, valid and reliable evaluation instruments specifically for the NBPP population are significantly lacking, manifesting in difficulties with evaluating the overall impact and effectiveness of clinical treatments in a consistent and comparative manner, extending across the various subspecialties that are involved in the treatment of patients with NBPP. The authors suggest that all ICF domains should be considered, and future efforts should include consideration of spontaneous (not practitioner-elicited) use of the affected arm in activities of daily living with attention to the psychosocial impact of the disablement.

Macrovascular decompression of the median nerve for posttraumatic neuralgic limb pain

Neuropathic pain is rare in children, and few reports provide adequate guidelines for treatment. The authors describe the successful treatment of tardy neuropathic pain via macrovascular decompression in a 15-year-old boy who presented with progressive pain 11 years following trauma to the upper extremity that had required surgical repair of the brachial artery. Examination revealed mild chronic median and ulnar motor neuropathy as well as recent progressive lancinating pain and a Tinel sign at the prior scar. A soft tissue mass in the neurovascular bundle at the site of previous injury was noted on MRI. Surgical exploration demonstrated an altered anatomical relationship of the previously repaired brachial artery and the median nerve, resulting in pulsatile compression of the median nerve by the brachial artery. Neurolysis and decompression of the median nerve with physical separation from the brachial artery resulted in immediate pain relief. This is the first report of macrovascular decompression of a major peripheral nerve with complete symptom resolution. Noninvasive imaging together with a thorough history and physical examination can support identification of this potential etiology of peripheral neuralgic pain. Recognition and treatment of this uncommon problem may yield improved outcomes for children with neuropathic pain.

Utility of electrodiagnostic testing and computed tomography myelography in the preoperative evaluation of neonatal brachial plexus palsy

OBJECT

The rate of neonatal brachial plexus palsy (NBPP) remains 0.4%-4% despite improvements in perinatal care. Among affected children, the extent of brachial plexus palsy differs greatly, as does the prognosis. Controversial elements in management include indications and timing of nerve repair as well as type of reconstruction in patients in whom function will ultimately not be recovered without surgical intervention. Differentiating preganglionic (avulsion) from postganglionic (rupture) lesions is critical because preganglionic lesions cannot spontaneously recover motor function. Distinguishing between these lesions at initial presentation based on clinical examination alone can be difficult in infants. The purpose of the present study was to determine the sensitivity of preoperative electrodiagnostic studies (EDSs) and CT myelography (CTM) in determining the presence of nerve root rupture and avulsions in infants with NBPP.

METHODS

After receiving institutional review board approval, the authors conducted a retrospective review of patients referred to the Neonatal Brachial Plexus Program between 2007 and 2010. Inclusion criteria included children who underwent brachial plexus exploration following preoperative EDSs and CTM. The CTM scans were interpreted by a staff neuroradiologist, EDSs were conducted by a single physiatrist, and intraoperative findings were recorded by the operating neurosurgeon. The findings from the preoperative EDSs and CTM were then compared with intraoperative findings. The sensitivities and 95% confidence intervals were determined to evaluate performance accuracy of each preoperative measure.

RESULTS

Twenty-one patients (8 male amd 13 female) met inclusion criteria for this study. The sensitivity of EDSs and CTM for detecting a postganglionic rupture was 92.8% (CI 0.841-0.969) and 58.3% (CI 0.420-0.729), respectively. The sensitivity for EDSs and CTM for preganglionic nerve root avulsion was 27.8% (CI 0.125-0.509) and 72.2% (CI 0.491-0.875), respectively. In cases in which both CTM and EDSs gave concordant results, the sensitivity for both modalities combined was 50.0% (CI 0.237-0.763) for avulsion and 80.8% (CI 0.621-0.915) for rupture. Overall, EDSs were most useful in identifying ruptures, particularly in the upper plexus, whereas CTM was most sensitive in identifying avulsions in the lower plexus.

CONCLUSIONS

Knowledge of the spinal nerve integrity is critical for early management of patients with NBPP. Surgical management, in the form of nerve repair/reconstruction, and optimal prognostication of NBPP depend on the accurate diagnosis of the level and type of lesion. Both EDSs and CTM scans must always be interpreted in the context of a comprehensive evaluation of the patient. They provide supplemental information (in addition to the physical examination) for early detection of nerve root rupture and avulsion injuries, aiding surgical decision making and preoperative planning for NBPP. Continued advances in imaging, EDSs, and microsurgical nerve repair techniques will allow surgeons to achieve greater success for functional recovery in management of NBPP.

Radiation-induced meningeal osteosarcoma of tentorium cerebelli with intradural spinal metastases

BACKGROUND

Primary meningeal osteosarcomas and radiation-induced extraosseous tumors are extremely rare. We encountered a patient with a radiation-induced meningeal osteosarcoma with metastatic spread.

CASE DESCRIPTION

A 54-year-old man presented with a 2-week history of nausea, vomiting, and ataxia. CT and MRI studies revealed an extra-axial, dural-based mass in the posterior fossa arising from the tentorium cerebelli. The patient underwent complete resection of the tumor with adjuvant chemotherapy. Histopathologic analysis revealed chondroblastic osteosarcoma. Tumor recurrence was observed 9 months after initial diagnosis, and adjuvant radiation therapy was administered. The intracranial disease stabilized; however, multiple cervico-thoracic spinal metastases were discovered 15 months after initial diagnosis. The patient expired 16 months after initial diagnosis.

CONCLUSION

Meningeal osteosarcomas are rare lesions that can metastasize and should be considered in the differential diagnosis for dural-based lesions, especially in the case of previous radiation therapy.

Sialidase enhances spinal axon outgrowth in vivo

The adult CNS is an inhibitory environment for axon outgrowth, severely limiting recovery from traumatic injury. This limitation is due, in part, to endogenous axon regeneration inhibitors (ARIs) that accumulate at CNS injury sites. ARIs include myelin-associated glycoprotein, Nogo, oligodendrocyte-myelin glycoprotein, and chondroitin sulfate proteoglycans (CSPGs). Some ARIs bind to specific receptors on the axon growth cone to halt outgrowth. Reversing or blocking the actions of ARIs may promote recovery after CNS injury. We report that treatment with sialidase, an enzyme that cleaves one class of axonal receptors for myelin-associated glycoprotein, enhances spinal axon outgrowth into implanted peripheral nerve grafts in a rat model of brachial plexus avulsion, a traumatic injury in which nerve roots are torn from the spinal cord. Repair using peripheral nerve grafts is a promising restorative surgical treatment in humans, although functional improvement remains limited. To model brachial plexus avulsion in the rat, C8 nerve roots were cut flush to the spinal cord and a peroneal nerve graft was inserted into the lateral spinal cord at the lesion site. Infusion of Clostridium perfringens sialidase to the injury site markedly increased the number of spinal axons that grew into the graft (2.6-fold). Chondroitinase ABC, an enzyme that cleaves a different ARI (CSPGs), also enhanced axon outgrowth in this model. In contrast, phosphatidylinositol-specific phospholipase C, which cleaves oligodendrocyte-myelin glycoprotein and Nogo receptors, was without benefit. Molecular therapies targeting sialoglycoconjugates and CSPGs may aid functional recovery after brachial plexus avulsion or other nervous system injuries and diseases.

Superficial peroneal nerve syndrome: an unusual nerve entrapment

✓Lower-extremity pain and paresthesia have multiple origins. Early recognition of the symptoms of peripheral nerve entrapment leads to timely treatment and avoids the cost of unnecessary studies. The authors report on a case of superficial peroneal nerve syndrome resulting from nerve herniation through a fascial defect, which was responsive to surgical treatment.

This 22-year-old man presented with pain and paresthesias over the lateral aspect of the right calf and the dorsum of the foot without motor weakness. Exercise led to the formation of a tender bulge approximately 12 cm above the lateral malleolus. Percussion of this site worsened his symptoms. Radiography and electromyography studies were nondiagnostic. The patient underwent surgical decompression that involved division of the fascia overlying the nerve and neurolysis of the superficial peroneal nerve. The operation resulted in symptom-free relief.

Superficial peroneal nerve syndrome is an entrapment neuropathy that results from mechanical compression of the nerve at or near the point where the nerve pierces the fascia to travel within the subcutaneous tissue. Surgical decompression of the mechanical entrapment usually provides relief from pain and paresthesia.

Progression of a posterior communicating artery infundibulum into an aneurysm in a patient with Alagille syndrome

✓ The authors present a case in which a posterior communicating artery (PCoA) infundibulum progressed into an aneurysm in a patient with Alagille syndrome (arteriohepatic dysplasia). The 3-mm PCoA infundibulum had been noted on angiography studies obtained 5 years earlier, prior to clip occlusion of a basilar tip aneurysm. Recently, the patient presented to the emergency department with the sudden onset of headache and decreased mental status. A computerized tomography scan of the head with three-dimensional angiography revealed no gross subarachnoid hemorrhage, but did demonstrate a 5-mm PCoA aneurysm. Lumbar puncture demonstrated xanthochromia and a large quantity of red blood cells. The patient underwent open surgery for aneurysm clip occlusion and obtained a good recovery.

This case illustrates the small but growing number of examples of infundibulum progression. It also indicates the need for a close follow up in patients with congenital abnormalities that may pose an increased risk for what has traditionally been considered a benign lesion.