G. Carl Huber (1865-1934): A Michigan Pioneer in Peripheral Nerve Injury and Regeneration

The treatment of peripheral nerve injuries has seen tremendous innovations over the past century. Dr Gotthelf Carl Huber, an American immigrant and early experimental pioneer in the field of peripheral nerve injury, created a foundation of scientific knowledge for these advancements. At the beginning of his career, Huber published novel work in peripheral nerve injury, supporting the concept of Wallerian degeneration and demonstrating the use of nerve grafting for repair. As his scientific career evolved into other research areas at the University of Michigan, Huber's impact extended far beyond just the study of peripheral nerve injury. Because of the external forces of the First World War, Dr Huber's focus returned to translational projects concentrated on the treatment of neuromas and war time peripheral nerve injuries. Huber's scientific impact in the field of peripheral nerve injury and repair came as a result of his incredible work ethic, mentorship, and tremendous leadership qualities; through this, his work still influences clinical practice today, a century later.

Core outcomes in nerve surgery: development of a core outcome set for brachial plexus and upper extremity nerve injuries

OBJECTIVE

When considering traumatic brachial plexus and upper extremity nerve injuries, iatrogenic nerve injuries, and nontraumatic nerve injuries, brachial plexus and upper extremity nerve injuries are commonly encountered in clinical practice. Despite this, data synthesis and comparison of available studies are difficult. This is at least in part due to the lack of standardization in reporting and a lack of a core outcome set (COS). Thus, there is a need for a COS for adult brachial plexus and upper extremity nerve injuries (COS-BPUE). The objective of this study was to develop a COS-BPUE using a modified Delphi approach.

METHODS

A 5-stage approach was used to develop the COS-BPUE: 1) consortium development, 2) literature review to identify potential outcome measures, 3) Delphi survey to develop consensus on outcomes for inclusion, 4) Delphi survey to develop definitions, and 5) consensus meeting to finalize the COS and definitions. The study followed the Core Outcome Set-STAndards for Development (COS-STAD) recommendations.

RESULTS

The Core Outcomes in Nerve Surgery (COINS) Consortium comprised 23 participants, all neurological surgeons, representing 13 countries. The final COS-BPUE consisted of 36 data points/outcomes covering demographic, diagnostic, patient-reported outcome, motor/sensory outcome, and complication domains. Appropriate instruments, methods of testing, and definitions were set. The consensus minimum duration of follow-up was 24 months, with the consensus optimal time points for assessment being preoperatively and 3, 6, 12, and 24 months postoperatively.

CONCLUSIONS

The COINS Consortium developed a consensus COS and provided definitions, methods of implementation, and time points for assessment. The COS-BPUE should serve as a minimum set of data that should be collected in all future neurosurgical studies on adult brachial plexus and upper extremity nerve injuries. Incorporation of this COS should help improve consistency in reporting, data synthesis, and comparability, and should minimize outcome reporting bias.

Core outcomes in nerve surgery: development of a core outcome set for ulnar neuropathy at the elbow

OBJECTIVE

Ulnar neuropathy at the elbow (UNE) is common, affecting 1%-6% of the population. Despite this, there remains a lack of consensus regarding optimal treatment. This is primarily due to the difficulty one encounters when trying to assess the literature. Outcomes are inconsistently reported, which makes comparing studies or developing meta-analyses difficult or even impossible. Thus, there is a need for a core outcome set (COS) for UNE (COS-UNE) to help address this problem. The objective of this study was to utilize a modified Delphi method to develop COS-UNE.

METHODS

A 5-stage approach was utilized to develop COS-UNE: stage 1, consortium development; 2, literature review to identify potential outcome measures; 3, Delphi survey to develop consensus on outcomes for inclusion; 4, Delphi survey to develop definitions; and 5, consensus meeting to finalize the COS and definitions. The study followed the Core Outcome Set-STAndards for Development (COS-STAD) recommendations.

RESULTS

The Core Outcomes in Nerve Surgery (COINS) Consortium comprised 21 participants, all neurological surgeons representing 11 countries. The final COS-UNE consisted of 22 data points/outcomes covering the domains of demographic characteristics, diagnostics, patient-reported outcomes, motor/sensory outcomes, and complications. Appropriate instruments, methods of testing, and definitions were set. The consensus minimum duration of follow-up was 6 months, with the consensus optimal timepoints for assessment identified as preoperatively and 3, 6, and 12 months postoperatively.

CONCLUSIONS

The authors identified consensus data points/outcomes and also provided definitions and specific scales to be utilized to help ensure that clinicians are consistent in their reporting across studies on UNE. This COS should serve as a minimum set of data to be collected in all future neurosurgical studies on UNE. The authors hope that clinicians evaluating ulnar neuropathy will incorporate this COS into routine practice and that future studies will consider this COS in the design phase.

Survey of United States neurosurgeons on firearm injury prevention

OBJECTIVE

Firearm-related injuries and deaths are an endemic problem in the US, posing a burden on the healthcare system with significant social and economic consequences. As front-line care providers for these patients, neurosurgeons are both knowledgeable about these injuries and credible messengers in the public discussion of ways to reduce firearm injuries. The purpose of this study was to explore US-based neurosurgeons' views and behaviors regarding firearms to understand and define a potential role for neurosurgical organizations in advocacy efforts to reduce firearm death and injuries.

METHODS

The authors conducted an anonymous survey of US neurosurgeons using the American Association of Neurological Surgeons (AANS) member database from April to June 2023. The 22-question survey included questions related to firearm ownership, personal views on firearms, and support for both general and policy-specific advocacy efforts to reduce firearm deaths and injuries.

RESULTS

The survey response rate was 20.7%, with 1568 of the 7587 members invited completing the survey. The survey completion rate was 93.4%, with 1465 of the 1568 surveys completed and included in this analysis. The majority of respondents were male (raw: 81.7%; weighted 81.1%), White (raw: 69.7%; weighted 70.2%), and older than 50 years (raw: 56.2%; weighted: 54%). Most respondents reported treating patients with firearm injuries (raw: 83.3%; weighted: 82%), 85.5% (weighted: 85.1%) had used a firearm, and 42.4% (weighted: 41.5%) reported owning a firearm. Overall, 78.8% (weighted: 78.7%) of respondents felt that organized neurosurgery should participate in advocacy efforts. When examining individual policies, those that restrict the acquisition of firearms garnered the support of at least 65% of respondents, while nonrestrictive policies were supported by more than 75% of respondents. Free-text responses provided insight into both motivations for and objections to organizational advocacy.

CONCLUSIONS

The majority of US-based neurosurgeons support involvement in advocacy efforts to reduce firearm deaths and injuries. Themes expressed by members both supporting and objecting to advocacy provide insight into approaches that could ensure broad support. Neurosurgical organizations such as the AANS and Congress of Neurological Surgeons may use the results of this survey to make informed decisions regarding involvement in advocacy efforts on behalf of their membership to lessen the burden of firearm injury in the US.

Effects of age and time since injury on traumatic brain injury blood biomarkers: a TRACK-TBI study

Older adults have the highest incidence of traumatic brain injury globally. Accurate blood-based biomarkers are needed to assist with diagnosis of patients across the spectrum of age and time post-injury. Several reports have suggested lower accuracy for blood-based biomarkers in older adults, and there is a paucity of data beyond day-1 post-injury. Our aims were to investigate age-related differences in diagnostic accuracy and 2-week evolution of four leading candidate blood-based traumatic brain injury biomarkers-plasma glial fibrillary acidic protein, ubiquitin carboxy-terminal hydrolase L1, S100 calcium binding protein B and neuron-specific enolase-among participants in the 18-site prospective cohort study Transforming Research And Clinical Knowledge in Traumatic Brain Injury. Day-1 biomarker data were available for 2602 participants including 2151 patients with traumatic brain injury, 242 orthopedic trauma controls and 209 healthy controls. Participants were stratified into 3 age categories (young: 17-39 years, middle-aged: 40-64 years, older: 65-90 years). We investigated age-stratified biomarker levels and biomarker discriminative abilities across three diagnostic groups: head CT-positive/negative; traumatic brain injury/orthopedic controls; and traumatic brain injury/healthy controls. The difference in day-1 glial fibrillary acidic protein, ubiquitin carboxy-terminal hydrolase L1 and neuron-specific enolase levels across most diagnostic groups was significantly smaller for older versus younger adults, resulting in a narrower range within which a traumatic brain injury diagnosis may be discriminated in older adults. Despite this, day-1 glial fibrillary acidic protein had good to excellent performance across all age-categories for discriminating all three diagnostic groups (area under the curve 0.84-0.96; lower limit of 95% confidence intervals all >0.78). Day-1 S100 calcium-binding protein B and ubiquitin carboxy-terminal hydrolase L1 showed good discrimination of CT-positive versus negative only among adults under age 40 years within 6 hours of injury. Longitudinal blood-based biomarker data were available for 522 hospitalized patients with traumatic brain injury and 24 hospitalized orthopaedic controls. Glial fibrillary acidic protein levels maintained good to excellent discrimination across diagnostic groups until day 3 post-injury irrespective of age, until day 5 post-injury among middle-aged or younger patients and until week 2 post-injury among young patients only. In conclusion, the blood-based glial fibrillary acidic protein assay tested here has good to excellent performance across all age-categories for discriminating key traumatic brain injury diagnostic groups to at least 3 days post-injury in this trauma centre cohort. The addition of a blood-based diagnostic to the evaluation of traumatic brain injury, including geriatric traumatic brain injury, has potential to streamline diagnosis.

MPNST without muscle weakness at presentation: an analysis of an underappreciated combination

INTRODUCTION

Malignant peripheral nerve sheath tumors (MPNSTs) of major motor nerves typically present with muscle weakness and pain. We aim to analyze and characterize patients with MPNST at major motor nerves but without muscle weakness at initial presentation.

METHODS

A retrospective search involving MPNSTs in a major nerve evaluated and/or treated at our institution from 1994 to 2019 was performed. Patients with no muscle weakness and available MRI were analyzed. Clinical materials, MR images and PET scans were reviewed for features of malignancy. This group of patients was compared to patients who presented with MPNSTs and muscle weakness.

RESULTS

Twenty-six patients were included in the no muscle weakness group. Of them, twenty-one (81%) patients had a positive family history for malignancy. Only 16 (62%) MR images were highly suspicious for malignancy. All 7 available PET-scans were highly suspicious for malignancy. Patients who presented with muscle weakness (n = 36), were more likely to have paresthesias and a history of NF-1 or radiation to the MPNST location (p-value < 0.05).

CONCLUSION

MPNSTs of major motor nerves without muscle weakness represent an underappreciated subset of cases which has potential treatment and outcome implications. These patients presented with fewer symptoms and had fewer risk factors than patients with muscle weakness. PET-scans should be considered as an extra method of trying to anticipate the diagnosis of an MPNST.

Plasma extracellular vesicles as a source of biomarkers in traumatic brain injury

OBJECTIVE

The objective of this study was to isolate extracellular vesicles (EVs) from plasma in a cohort of patients with traumatic brain injury (TBI) and analyze their contents for novel biomarkers that could prove useful for rapid diagnosis and classification of brain injury during initial evaluation.

METHODS

Plasma EVs were isolated by serial ultracentrifugation from patients with TBI (n = 15) and healthy controls (n = 5). Samples were obtained from the TRACK-TBI biorepository (2010–present). Size and concentration were determined by nanoparticle tracking. Glial fibrillary acidic protein (GFAP) concentration was determined in EV protein. EV RNA was isolated and deep sequencing of short noncoding RNA was performed.

RESULTS

Plasma EVs are physically similar but contained approximately 10 times more GFAP in TBI patients with altered consciousness than patients and controls with normal consciousness. Eleven highly differentially expressed microRNAs (miRNAs) were identified between these groups. Genes targeted by these miRNAs are highly associated with biologically relevant cellular pathways, including organismal injury, cellular development, and organismal development. Multiple additional coding and noncoding RNA species with potential biomarker utility were identified.

CONCLUSIONS

Isolating plasma EVs in patients with TBI is feasible. Increased GFAP concentration—a validated plasma TBI marker—in EVs from TBI patients with altered consciousness, along with differential expression of multiple miRNAs targeting TBI-relevant pathways, suggests that EVs may be a useful source of TBI biomarkers. Additional evaluation in larger patient cohorts is indicated.

High-Sensitivity C-Reactive Protein is a Prognostic Biomarker of Six-Month Disability after Traumatic Brain Injury: Results from the TRACK-TBI Study

Systemic inflammation impacts outcome after traumatic brain injury (TBI), but most TBI biomarker studies have focused on brain-specific proteins. C-reactive protein (CRP) is a widely used biomarker of inflammation with potential as a prognostic biomarker after TBI. The Transforming Research and Clinical Knowledge in Traumatic Brain Injury (TRACK-TBI) study prospectively enrolled TBI patients within 24 h of injury, as well as orthopedic injury and uninjured controls; biospecimens were collected at enrollment. A subset of hospitalized participants had blood collected on day 3, day 5, and 2 weeks. High-sensitivity CRP (hsCRP) and glial fibrillary acidic protein (GFAP) were measured. Receiver operating characteristic analysis was used to evaluate the prognostic ability of hsCRP for 6-month outcome, using the Glasgow Outcome Scale-Extended (GOSE). We included 1206 TBI subjects, 122 orthopedic trauma controls (OTCs), and 209 healthy controls (HCs). Longitudinal biomarker sampling was performed in 254 hospitalized TBI subjects and 19 OTCs. hsCRP rose between days 1 and 5 for TBI and OTC subjects, and fell by 2 weeks, but remained elevated compared with HCs (p < 0.001). Longitudinally, hsCRP was significantly higher in the first 2 weeks for subjects with death/severe disability (GOSE <5) compared with those with moderate disability/good recovery (GOSE ≥5); AUC was highest at 2 weeks (AUC = 0.892). Combining hsCRP and GFAP at 2 weeks produced AUC = 0.939 for prediction of disability. Serum hsCRP measured within 2 weeks of TBI is a prognostic biomarker for disability 6 months later. hsCRP may have utility as a biomarker of target engagement for anti-inflammatory therapies.

Point-of-Care Platform Blood Biomarker Testing of Glial Fibrillary Acidic Protein versus S100 Calcium-Binding Protein B for Prediction of Traumatic Brain Injuries: A Transforming Research and Clinical Knowledge in Traumatic Brain Injury Study

Glial fibrillary acidic protein (GFAP) is cleared by the Food and Drug Administration (FDA) to determine need for head computed tomography (CT) within 12 h after mild traumatic brain injury (TBI) (Glasgow Coma Score [GCS] 13-15); S100 calcium-binding protein B (S100B) serves this function in Europe. This phase 1 biomarker cohort analysis of the multi-center, observational Transforming Research and Clinical Knowledge in Traumatic Brain Injury (TRACK-TBI) study compares GFAP's diagnostic performance, measured on a rapid point-of-care platform, against protein S100B to predict intracranial abnormalities on CT within 24 h post-injury across the spectrum of TBI (GCS 3-15). Head CT scan performed in TBI subjects and blood was collected for all consenting subjects presenting to 18 United States level 1 trauma centers. Plasma was analyzed on a point-of-care device prototype assay for GFAP and serum was analyzed for S100B. In 1359 patients with TBI (GCS 3-15), mean (standard deviation [SD]) age = 40.1 (17.0) years; 68% were male. Plasma GFAP levels were significantly higher in CT+ TBI subjects (median = 1358 pg/mL, interquartile range [IQR]: 472-3803) than in CT- TBI subjects (median = 116 pg/mL, IQR: 26-397) or orthopedic trauma controls (n = 122; median = 13 pg/mL, IQR: 7-20), p < 0.001. Serum S100B levels were likewise higher in CT+ TBI subjects (median = 0.17 μg/L, IQR: 0.09-0.38) than in CT- TBI subjects (median = 0.10 μg/L, IQR: 0.06-0.18), p < 0.001. Receiver operating characteristic curves were generated for prediction of intracranial injury on admission CT scan; area under the curve (AUC) for GFAP was significantly higher than for S100B in the same cohort (GFAP AUC - 0.85, 95% confidence interval [CI] 0.83-0.87; S100B AUC - 0.67, 95% CI 0.64-0.70; p < 0.001). GFAP, measured on a point-of-care platform prototype assay, has high discriminative ability to predict intracranial abnormalities on CT scan in patients with TBI across the full injury spectrum of GCS 3-15 through 24 h post-injury. GFAP substantially outperforms S100B.

Morbidity and mortality in elderly patients undergoing evacuation of acute traumatic subdural hematoma

OBJECTIVE

Acute traumatic subdural hematoma (atSDH) can be a life-threatening neurosurgical emergency that necessitates immediate evacuation. The elderly population can be particularly vulnerable to tearing bridging veins. The aim of this study was to evaluate inpatient morbidity and mortality, as well as predictors of inpatient mortality, in a national trauma database.

METHODS

The authors queried the 2016–2017 National Trauma Data Bank registry for patients aged 65 years and older who had undergone evacuation of atSDH. Patients were categorized into three age groups: 65–74, 75–84, and 85+ years. A multivariable logistic regression model was fitted for inpatient mortality adjusting for age group, sex, race, presenting Glasgow Coma Scale (GCS) category (3–8, 9–12, and 13–15), Injury Severity Score, presence of coagulopathy, presence of additional hemorrhages (epidural hematoma [EDH], intraparenchymal hematoma [IPH], and subarachnoid hemorrhage [SAH]), presence of midline shift > 5 mm, and pupillary reactivity (both, one, or none).

RESULTS

A total of 2508 patients (35% females) were analyzed. Age distribution was as follows: 990 patients at 65–74 years, 1096 at 75–84, and 422 at 85+. Midline shift > 5 mm was present in 72% of cases. With regard to additional hemorrhages, SAH was present in 21%, IPH in 10%, and EDH in 2%. Bilaterally reactive pupils were noted in 90% of patients. A major complication was observed in 14.4% of patients, and the overall mortality rate was 18.3%. In the multivariable analysis, the presenting GCS category was found to be the strongest predictor of postoperative inpatient mortality (3–8 vs 13–15: OR 3.63, 95% CI 2.68–4.92, p < 0.001; 9–12 vs 13–15: OR 2.64, 95% CI 1.79–3.90, p < 0.001; 30% of overall variation), followed by the presence of SAH (OR 2.86, 95% CI 2.21–3.70, p < 0.001; 25% of overall variation) and the presence of midline shift > 5 mm (OR 2.40, 95% CI 1.74–3.32, p < 0.001; 11% of overall variation). Model discrimination was excellent (c-index 0.81). Broken down by age decile group, mortality increased from 8.0% to 15.4% for GCS 13–15 to around 36% for GCS 9–12 to almost as high as 60% for GCS 3–8, particularly in those aged 85 years and older.

CONCLUSIONS

The present results from a national trauma database will, the authors hope, assist surgeons in preoperative discussions with patients and their families with regard to expected postoperative outcomes following surgical evacuation of an atSDH.

Sonographic evaluation of the lateral femoral cutaneous nerve in meralgia paresthetica

OBJECTIVE

Identify sonographic features of the lateral femoral cutaneous nerve (LFCN) in meralgia paresthetica (MP) and report therapeutic outcomes in sonographically confirmed cases.

MATERIALS AND METHODS

Retrospective review of 50 patients with clinically suspected MP and 20 controls. Ultrasounds were reviewed for characteristics of the LFCN and compared between groups. When available, MRIs were reviewed. In cases of sonographically pathologic LFCN, subsequent therapeutic interventions were recorded.

RESULTS

Thirty-five of the suspected MP cases (70%) had ultrasound findings suggestive of MP, 10 (20%) were negative, and in 5 (10%) the LFCN was not seen. Sonographic findings in positive cases included nerve enlargement in all cases (mean cross-sectional area 9 mm² (standard deviation (SD) ± 5.59) versus 4 mm² (SD ± 2.31) and 3 mm² (SD ± 2.31) in negative cases and normal controls, respectively; p < 0.01), nerve hypoechogenicity (30 of 35 cases, 86%), and focal lesion (7 of 35 cases, 20%). Sixteen ultrasounds positive for MP had MRIs with only 4 (25%) reporting a concordant LFCN abnormality (enlargement or T2 hyperintensity). Twenty-five of the 35 (71%) patients with positive sonographic findings for MP had a US-guided LFCN block (local anesthetic ± corticosteroid), with 24 of 25 (96%) patients reporting immediate symptomatic improvement. Eighteen of 35 (51%) underwent LFCN neurectomy or neurolysis, all of whom experienced symptomatic improvement.

CONCLUSION

Ultrasound is a useful modality for LFCN assessment in clinically suspected MP and is more sensitive for abnormalities than MRI. Nearly all patients who received perineural analgesia and/or neurectomy or neurolysis had symptomatic improvement.

Synovial Sarcoma of the Nerve-Clinical and Pathological Features: Case Series and Systematic Review

BACKGROUND

Synovial sarcoma of the nerve is a rare entity with several cases and case series reported in the literature. Despite an improved understanding of the biology, the clinical course is difficult to predict.

OBJECTIVE

To compile a series of patients with synovial sarcoma of the peripheral nerve (SSPN) and assess clinical and pathological factors and their contribution to survival and recurrence.

METHODS

Cases from 2 institutions collected in patients undergoing surgical intervention for SSPN. Systematic review including PubMed and Scopus databases were searched for related articles published from 1970 to December 2018. Eligibility criteria: (1) case reports or case series reporting on SSPN, (2) clinical course and/or pathological features of the tumor reported, and (3) articles published in English.

RESULTS

From patients treated at our institutions (13) the average follow-up period was 3.2 yr. Tumor recurrence was seen in 4 cases and death in 3. Systematic review of the literature yielded 44 additional cases with an average follow-up period of 3.6 yr. From pooled data, there were 10 recurrences and 7 deaths (20% and 14%, respectively). Adjuvant treatment used in 62.5% of cases. Immunohistochemical markers used in diagnosis varied widely; the most common are the following: Epithelial membrane antigen (EMA), cytokeratin, vimentin, cluster of differentiation (CD34), and transducin-like enhancer of split 1 (TLE1). Statistical analysis illustrated tumor size and use of chemotherapy to be negative predictors of survival. No other factors, clinically or from pathologist review, were correlated with recurrence or survival.

CONCLUSION

By combining cases from our institution with historical data and performing statistical analysis we show correlation between tumor size and death.

Long-term outcome in traumatic brain injury patients with midline shift: a secondary analysis of the Phase 3 COBRIT clinical trial

OBJECTIVE

Following traumatic brain injury (TBI), midline shift of the brain at the level of the septum pellucidum is often caused by unilateral space-occupying lesions and is associated with increased intracranial pressure and worsened morbidity and mortality. While outcome has been studied in this population, the recovery trajectory has not been reported in a large cohort of patients with TBI. The authors sought to utilize the Citicoline Brain Injury Treatment (COBRIT) trial to analyze patient recovery over time depending on degree of midline shift at presentation.

METHODS

Patient data from the COBRIT trial were stratified into 4 groups of midline shift, and outcome measures were analyzed at 30, 90, and 180 days postinjury. A recovery trajectory analysis was performed identifying patients with outcome measures at all 3 time points to analyze the degree of recovery based on midline shift at presentation.

RESULTS

There were 892, 1169, and 895 patients with adequate outcome data at 30, 90, and 180 days, respectively. Rates of favorable outcome (Glasgow Outcome Scale-Extended [GOS-E] scores 4-8) at 6 months postinjury were 87% for patients with no midline shift, 79% for patients with 1-5 mm of shift, 64% for patients with 6-10 mm of shift, and 47% for patients with > 10 mm of shift. The mean improvement from unfavorable outcome (GOS-E scores 2 and 3) to favorable outcome (GOS-E scores 4-8) from 1 month to 6 months in all groups was 20% (range 4%-29%). The mean GOS-E score for patients in the 6- to 10-mm group crossed from unfavorable outcome (GOS-E scores 2 and 3) into favorable outcome (GOS-E scores 4-8) at 90 days, and the mean GOS-E of patients in the > 10-mm group nearly reached the threshold of favorable outcome by 180 days postinjury.

CONCLUSIONS

In this secondary analysis of the Phase 3 COBRIT trial, TBI patients with less than 10 mm of midline shift on admission head CT had significantly improved functional outcomes through 180 days after injury compared with those with greater than 10 mm of midline shift. Of note, nearly 50% of patients with > 10 mm of midline shift achieved a favorable outcome (GOS-E score 4-8) by 6 months postinjury.

Teriparatide treatment increases Hounsfield units in the lumbar spine out of proportion to DEXA changes

OBJECTIVE

The authors sought to assess whether Hounsfield units (HU) increase following teriparatide treatment and to compare HU increases with changes in bone mineral density (BMD) as measured by dual-energy x-ray absorptiometry (DEXA).

METHODS

A retrospective chart review was performed from 1997 to 2018 across all campuses at our institution. The authors identified patients who had been treated with at least 6 months of teriparatide and compared HU and BMD as measured on DEXA scans before and after treatment.

RESULTS

Fifty-two patients were identified for analysis (46 women and 6 men, average age 67 years) who underwent an average of 20.9 ± 6.5 months of teriparatide therapy. The mean ± standard deviation HU increase throughout the lumbar spine (L1-4) was from 109.8 ± 53 to 133.9 ± 61 HU (+22%, 95% CI 1.2-46, p value = 0.039). Based on DEXA results, lumbar spine BMD increased from 0.85 to 0.93 g/cm2 (+9%, p value = 0.044). Lumbar spine T-scores improved from -2.4 ± 1.5 to -1.7 ± 1.5 (p value = 0.03). Average femoral neck T-scores improved from -2.5 ± 1.1 to -2.3 ± 1.0 (p value = 0.31).

CONCLUSIONS

Teriparatide treatment increased both HU and BMD on DEXA in the lumbar spine, without a change in femoral BMD. The 22% improvement in HU surpassed the 9% improvement determined with DEXA. These results support some surgeons' subjective sense that intraoperative bone quality following teriparatide treatment is better than indicated by DEXA results. To the authors' knowledge, this is the first study demonstrating an increase in HU with teriparatide treatment.

The medial safe zone for treating intraneural ganglion cysts in the tarsal tunnel: a technical note

INTRODUCTION

Intraneural ganglion cysts in the tarsal tunnel are rare but are being increasingly reported. The cysts involve the tibial or plantar nerves and are most commonly derived from a neighboring (degenerative) joint, (i.e., the tibiotalar or subtalar) via an articular branch arising from the medial aspect of the nerve. We describe a safe zone for approaching these cysts in the tarsal tunnel that allows for identification of the joint connection without injury to important distal branches.

METHODS

We present a case of an intraneural ganglion cyst within the tarsal tunnel in a patient with symptoms consistent with tarsal tunnel syndrome. Using intraoperative photographs and artist rendering, we describe a technique to safely disconnect the abnormal joint connection while preserving the important distal branches of the tibial nerve.

CONCLUSION

The safe zone for the tibial nerve in the tarsal tunnel can be exposed by mobilization and gentle retraction of the vascular bundle. In cases of intraneural ganglion cysts, all apparent connections between the nerve and degenerative joints within this safe zone can be resected without injury to important distal nerve branches.

Avoidance of scapular winging while approaching tumors of the middle scalene region

BACKGROUND

Large tumors arising from the middle scalene region can displace the middle scalene muscle and distort regional anatomy, placing nerves at risk. Understanding the surgical anatomy of these nerves is key to approaching pathology of the middle scalene muscle and avoiding damage to the dorsal scapular, long thoracic, and spinal accessory nerves, each of which can cause scapular winging and associated morbidity if injured.

METHODS

IRB approval was obtained for this study, allowing cases with relevant pathology to be reviewed and presented to highlight the relevant surgical technique. Anatomical depictions were created to correlate intraoperative images with known anatomical relationships.

RESULTS

Key to this approach is consideration of the regional anatomy in a standard supraclavicular approach, the superficial plane, containing the anterior scalene muscle and brachial plexus, and the oblique plane containing the middle scalene muscle, long thoracic, spinal accessory, and dorsal scapular nerves. Identification and mobilization of each of these structures prior to lesion removal can not only provide likely boundaries of the tumor, but also allow for protection of the nerves to avoid injury that may lead to scapular winging with associated morbidity and functional impairment of the upper extremity.

CONCLUSIONS

Lesions of the middle scalene region often split two important anatomical planes, the superficial and deep, creating an advantageous surgical corridor through an anterolateral approach. Through early identification of known anatomy, these two planes can be developed, and a safe approach to the lesion of the middle scalene region can be exploited.

[18F]FDG, [11C]PiB, and [18F]AV-1451 PET Imaging of Neurodegeneration in Two Subjects With a History of Repetitive Trauma and Cognitive Decline

Background: Trauma-related neurodegeneration can be difficult to differentiate from multifactorial neurodegenerative syndromes, both clinically and radiographically. We have initiated a protocol for in vivo imaging of patients with suspected TBI-related neurodegeneration utilizing volumetric MRI and PET studies, including [¹⁸F]FDG indexing cerebral glucose metabolism, [¹¹C]PiB for Aβ deposition, and [¹⁸F]AV-1451 for tau deposition. Objective: To present results from a neuroimaging protocol for in vivo evaluation of TBI-related neurodegeneration in patients with early-onset cognitive decline and a history of TBI. Methods: Patients were enrolled in parallel TBI studies and underwent a comprehensive neuropsychological test battery as well as an imaging protocol of volumetric MRI and PET studies. Findings from two patients were compared with two age-matched control subjects without a history of TBI. Results: Both chronic TBI patients demonstrated cognitive deficits consistent with early-onset dementia on neuropsychological testing, and one patient self-reported a diagnosis of probable early-onset AD. Imaging studies demonstrated significant [¹⁸F]AV-1451 uptake in the bilateral occipital lobes, substantial [¹¹C]PiB uptake throughout the cortex in both TBI patients, and abnormally decreased [¹⁸F]FDG uptake in the posterior temporoparietal areas of the brain. One TBI patient also had subcortical volume loss. Control subjects demonstrated no appreciable [¹⁸F]AV-1451 or [¹¹C]PiB uptake, had normal cortical volumes, and had normal cognition profiles on neuropsychological testing. Conclusions: In the two patients presented, the [¹¹C]PiB and [¹⁸F]FDG PET scans demonstrate uptake patterns characteristic of AD. [¹¹C]PiB PET scans showed widespread neocortical uptake with less abnormal uptake in the occipital lobes, whereas there was significant [¹⁸F]AV-1451 uptake in both occipital lobes.

H3K27 trimethylation loss in malignant peripheral nerve sheath tumor: a systematic review and meta-analysis with diagnostic implications

BACKGROUND

Multiple studies have reported the loss of trimethylation at lysine (K) 27 on histone 3 (H3K27me3) in high-grade malignant peripheral nerve sheath tumors (MPNSTs). However, the diagnostic potential of this finding in MPNSTs remains yet to be fully substantiated. Correspondingly, our aim was to pool systematically-identified metadata in the literature and substantiate the incidence of H3K27me3 loss in this setting.

METHODS

Searches of 7 electronic databases from inception to May 2019 were conducted following PRISMA guidelines. Articles were screened against pre-specified criteria. The incidence of loss was then pooled by random-effects meta-analysis of proportions.

RESULTS

Nine pertinent studies described a total of 823 high-grade MPNST samples. When pooled, incidence (sensitivity) of complete H3K27me3 loss was estimated to be 53% (95% CI 42-64%). For MPNST subtypes, estimated incidences of complete loss in NF1 subtype was 52% (95% CI 41-62), in sporadic subtype was 53% (95% CI 36-70%), in the epithelioid subtype was 0% (95% CI 0-7%), and radiation-associated subtype was 98% (95% CI 86-100%). Finally, incidence of incomplete loss (specificity) in 1231 MPNST-mimic samples was estimated to be 96% (95% CI 90-99%). Certainty of these outcomes ranged from very low to high.

CONCLUSIONS

The incidence of complete H3K27me3 loss is substantial in high-grade MPNSTs and is low in MPNST-mimics. Greater cohort study and biological investigation will validate the certainty of these findings as well as elucidate their true molecular and clinical significances.

Tarlov Cyst Causing Sacral Insufficiency Fracture

BACKGROUND AND IMPORTANCE

Tarlov cysts, also known as perineural cysts, have been described as meningeal dilations of the spinal nerve root sheath between the peri- and endoneurium at the dorsal root ganglion. Most often they are found in the sacrum involving the nerve roots. Normally asymptomatic, they have been reported to present with radiculopathy, paresthesias, and even urinary or bowel dysfunction. Sacral insufficiency has not been a well-documented presentation.

CLINICAL PRESENTATION

The patient is a 38-year-old female who started to develop left low back pain and buttock pain that rapidly progressed into severe pain with some radiation down the posterior aspect of her left leg. There was no recent history of spine or pelvic trauma. These symptoms prompted her initial emergency department evaluation, and imaging demonstrated a large Tarlov cyst with an associated sacral insufficiency fracture. She was noted to have a normal neurological examination notable only for an antalgic gait. She was taken to surgery via a posterior approach and the cyst was identified eccentric to the left. The cyst was fenestrated and the nerve roots identified. Given her large area of bone erosion and insufficiency fractures, fixation of the sacroiliac joints was deemed necessary. Fusion was extended to the L5 vertebral body to buttress the fixation. She tolerated the procedure well and was discharged from the hospital on postoperative day 3.

CONCLUSION

Tarlov cysts of the sacrum can lead to significant bone erosion and subsequent insufficiency fractures, requiring fenestration and in some cases, complex sacropelvic fixation.

Interfascicular Resection of Benign Peripheral Nerve Sheath Tumors

Background

Interfascicular resection is a surgical technique used to safely treat benign peripheral nerve sheath tumors through careful dissection of functional neural elements off the tumor surface^1,2.

Description

Proper operative technique is essential to improving symptoms, preserving neurologic function, and minimizing the chance for recurrence. Accurate tumor localization, ideal patient positioning, and placement of a longitudinal incision permit adequate exposure. Prior to tumor resection, normal nerve should be identified proximally and distally and controlled with vessel loops. This allows functional fascicles streaming around the tumor in the pseudocapsule to be visualized during resection. A fascicle-free window is identified on the tumor surface through visual inspection and intraoperative neurophysiology monitoring if desired. The pseudocapsule layers are divided with a sharp instrument until a smooth and shiny true capsule layer is found. This plane should have minimal resistance and is developed circumferentially until the tumor can be enucleated in toto. At the poles of the tumor, a single nonfunctional nerve fascicle that courses into the tumor is typically found. If there is >1 fascicle running into the tumor, further pseudocapsule layers should be undermined to sweep fascicles off the true capsule surface. The entering-exiting fascicle can be tested for function and is cut sharply. The specimen should be sent to pathology for permanent sectioning. The sides of the pseudocapsule are spread in opposite directions to evaluate for residual tumor, and any remaining tumor is removed if it can be done safely. Meticulous hemostasis is achieved, and the surgical site is closed in anatomical layers.

Alternatives

Pain is the most common presenting symptom, and neuroleptic medications should be used in escalating dosage prior to surgical intervention. Nonoperative medical therapy does not typically result in symptom freedom, and patients often opt for resection. For tumors that are suspected of being malignant, an image-guided percutaneous or open biopsy and staging (positron emission tomography and/or computed tomography scans of the chest, abdomen, and pelvis) are recommended prior to treatment planning. For symptomatic benign extremity lesions, surgical resection is the treatment of choice, and adjuvant therapies like radiation and/or chemotherapy are not recommended. For malignant lesions, more aggressive surgery (wide resection or amputation) and preoperative, intraoperative, or postoperative radiation with or without chemotherapy are often utilized.

Rationale

The treatment approach depends on a variety of presenting features such as onset, progression, symptom severity, tumor size, location, imaging features, presence of a syndrome, and patient age. There is little benefit from the resection of an incidentally found, small, nongrowing lesion. The most common reasons for removal of extremity lesions are a painful mass and/or radiating "nerve" pain. There is a high likelihood of relieving the symptoms and minimizing the risk of recurrence, and a relatively low risk of causing neurologic injury. The procedure provides a definitive diagnosis. For patients with severe pain, progressive weakness, rapid tumor growth, or concerning imaging characteristics, biopsy should be considered to determine malignant potential.

Division of Sacrospinous and Sacrotuberous Ligaments Expands Access Through Greater Sciatic Foramen: Anatomic Study with Application to Resection of Greater Sciatic Foramen Tumors

OBJECTIVE

Tumors of the greater sciatic foramen remain difficult to treat. They often have both intrapelvic and extrapelvic components that may limit visualization and make safe resection of the tumor difficult. Therefore the goal of the present anatomic study was to quantitate how much additional surgical working space could be gained by transection of the sacrospinous and sacrotuberous ligaments.

METHODS

Sixteen sides from 9 fresh-frozen Caucasian cadaveric torsos underwent transgluteal dissection and exposure of the greater sciatic foramen and associated liagments. With the piriformis in place, the vertical and horizontal diameters of the greater sciatic foramen were measured. Next, the sacrotuberous and sacrospinous ligaments were cut at their ischial attachments. The vertical diameter of the now confluent greater and lesser sciatic foramina (V₂) was measured.

RESULTS

The mean vertical diameter of the greater sciatic foramen (V₁) was 54.8 ± 9.7 mm. The horizontal diameter of the greater sciatic foramen had a mean of 44.3 ± 6.1 mm with a range of 30-52 mm. After transection of the sacrotuberous and sacrospinous ligaments, the vertical distance of the greater and lesser sciatic foramina (V₂) had a mean of 74.8 ± 6.8 mm with a range of 60.1-90 mm. The mean ratio of V₂ to V₁ was 1.40.

CONCLUSIONS

The vertical length of the greater sciatic foramen increased, on average, 40% after resection of the sacrotuberous and sacrospinous ligaments. The results of this study support an alternative technique for resecting large intrapelvic tumors via a transgluteal approach.

Age and sex-mediated differences in six-month outcomes after mild traumatic brain injury in young adults: a TRACK-TBI study

Introduction: Risk factors for young adults with mTBI are not well understood. Improved understanding of age and sex as risk factors for impaired six-month outcomes in young adults is needed. Methods: Young adult mTBI subjects aged 18-39 years (18-29y; 30-39y) with six-month outcomes were extracted from the Transforming Research and Clinical Knowledge in Traumatic Brain Injury Pilot (TRACK-TBI Pilot) study. Multivariable regressions were performed for outcomes with age, sex, and the interaction factor age-group*sex as variables of interest, controlling for demographic and injury variables. Mean-differences (B) and 95% CIs are reported. Results: One hundred mTBI subjects (18-29y, 70%; 30-39y, 30%; male, 71%; female, 29%) met inclusion criteria. On multivariable analysis, age-group*sex was associated with six-month post-traumatic stress disorder (PTSD; PTSD Checklist-Civilian version); compared with female 30-39y, female 18-29y (B= -19.55 [-26.54, -4.45]), male 18-29y (B= -19.70 [-30.07, -9.33]), and male 30-39y (B= -15.49 [-26.54, -4.45]) were associated with decreased PTSD symptomatology. Female sex was associated with decreased six-month functional outcome (Glasgow Outcome Scale-Extended (GOSE): B= -0.6 [1.0, -0.1]). Comparatively, 30-39y scored higher on six-month nonverbal processing speed (Wechsler Adult Intelligence Scale-Processing Speed Index (WAIS-PSI); B= 11.88, 95% CI [1.66, 22.09]). Conclusions: Following mTBI, young adults aged 18-29y and 30-39y may have different risks for impairment. Sex may interact with age for PTSD symptomatology, with females 30-39y at highest risk. These results may be attributable to cortical maturation, biological response, social modifiers, and/or differential self-report. Confirmation in larger samples is needed; however, prevention and rehabilitation/counseling strategies after mTBI should likely be tailored for age and sex.

Recovery Trajectories and Long-Term Outcomes in Traumatic Brain Injury: A Secondary Analysis of the Phase 3 Citicoline Brain Injury Treatment Clinical Trial

BACKGROUND

Prospects for recovery after traumatic brain injury (TBI) are often underestimated, potentially leading to withdrawal of care in the comatose TBI patient who may ultimately have a favorable outcome with aggressive care. Outcomes and trajectories of recovery in a large series of patients with TBI were evaluated at 30, 90, and 180 days postinjury.

METHODS

A secondary analysis of the phase 3 Citicoline Brain Injury Treatment (COBRIT) trial was performed analyzing recovery trajectories and long-term outcomes at 30, 90, and 180 days postinjury. A Glasgow Outcome Scale-Extended (GOS-E) score of 5 or higher was considered favorable. Pearson χ² analysis was used, and a P value of 0.05 was considered significant. A locally weighted, polynomial regression model was used to model recovery trajectories in a nonlinear fashion.

RESULTS

Subjects with TBI in the COBRIT trial had high rates of favorable outcome (57% of severe TBI, 86% of moderate TBI, and 93% of complicated mild TBI) at 6-month follow-up. These favorable outcomes often converted from high rates of unfavorable outcome at initial 1-month follow-up (85% of severe TBI, 57% of moderate TBI, and 21% of complicated mild TBI). Recovery trajectories had not plateaued at 6 months, suggesting that further improvement occurs beyond 6 months postinjury.

CONCLUSIONS

In this secondary analysis of the COBRIT trial, most patients had favorable outcomes by the GOS-E at 6 months postinjury in all complicated mild and moderate TBI groups, with over half of patients with severe TBI achieving a favorable outcome as well. Of subjects in a vegetative state (GOS-E score 2) at 1 month postinjury, 18% improved to a favorable outcome by 6 months postinjury. There was substantial improvement in all groups from 1 to 6 months, and this improvement may continue beyond 6 months. Clinical trials in TBI should consider recovery curves with repeated measures to assess outcomes because arbitrary single-moment outcome determination likely underestimates treatment effect in TBI care.

Bilateral brachial plexus injury after MiraDry® procedure for axillary hyperhidrosis: a case report

Multiple treatments are available for primary axillary hyperhidrosis, including non-invasive, microwave based thermal treatments designed to destroy sweat glands in the axilla. Often these procedures involve local anesthetic injection to the axilla, followed by placement of the microwave emitter onto the skin and applying the heat treatment to varying depths of the subcutaneous tissues. CASE REPORT: A 49-year old, thin and active woman (BMI 19.6) underwent microwave based treatment to the bilateral axillary regions. She experienced an electric sensation into the ulnar digits of the right hand during anesthetic injection, and then underwent the microwave thermal treatment. She suffered a bilateral brachial plexus injury with imaging evidence of severe, subcutaneous edema surrounding the nerves of the plexus in the axilla, as well as denervation atrophy of the arm and forearm muscles bilaterally. At the time of evaluation and EMG, 8 months after treatment, she had recovered significant strength in the left upper extremity, but continued to have evidence of a severe radial nerve injury on the right. EMG demonstrated some recovery and observation was recommended followed by secondary reconstruction if required. It is likely that the patient sustained thermal injury to the nerves in the axilla bilaterally, given the close proximity to the skin surface in a patient with a low BMI. CONCLUSION: In thin patients undergoing treatment of primary axillary hyperhidrosis, consideration should be given to the distal brachial plexus which may be at risk of damage with high powered microwave-based therapy.

Synchronous Development of Multicentric Malignant Peripheral Nerve Sheath Tumors: Institutional Review

BACKGROUND

Malignant peripheral nerve sheath tumors (MPNSTs) are rare soft tissue sarcomas, with approximately 50% occurring in patients diagnosed with neurofibromatosis type 1 (NF-1). NF-1 occurs in approximately 1/3000 individuals, and given that the lifetime prevalence of MPNST is estimated at 8%-13%, synchronous development of separate MPNSTs is plausible. We sought to report the incidence of synchronous MPNST in a cohort of pathology-proven cases since 1994.

METHODS

Records since 1994 were queried and identified 192 patients with pathology-proven MPNST. Medical records of these patients were reviewed to search for patients with synchronous MPNSTs.

RESULTS

Retrospective review of 192 patients treated for MPNST at our institution (including 71 patients with NF-1) revealed only 1 patient with synchronous MPNSTs. A 48-year-old woman with NF-1 presented with progressive right upper and lower extremity pain and radicular symptoms. Biopsies of right sciatic and median nerve lesions revealed high-grade MPNST, and she underwent radiotherapy and complete resection of both masses. Due to initial nonspecific biopsy results and patient preference, treatment of the median nerve lesion was delayed by 8 months. She did not have recurrence of her disease at the 18-month follow-up.

CONCLUSIONS

Synchronous development of MPNST is unusual, with an incidence of 1.4% in our cohort of NF-1 patients with MPNSTs. Given the reported incidence of synchronous MPNST, the rate of malignant transformation in NF-1 may be overestimated. However, heightened suspicion for malignant transformation should continue in patients harboring a diagnosis of MPNST.

The implications of intradural extension in paraspinal malignant peripheral nerve sheath tumors: effects on central nervous system metastases and overall survival

OBJECTIVE

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Temporal lobe contusions on computed tomography are associated with impaired 6-month functional recovery after mild traumatic brain injury: a TRACK-TBI study

INTRODUCTION

Mild traumatic brain injury (MTBI) can cause persistent functional deficits and healthcare burden. Understanding the association between intracranial contusions and outcome may aid in MTBI treatment and prognosis.

METHODS

MTBI patients with Glasgow Coma Scale 13-15 and 6-month outcomes [Glasgow Outcome Scale-Extended (GOSE)], without polytrauma from the prospective TRACK-TBI Pilot study were analyzed. Intracranial contusions on computed tomography (CT) were coded by location. Multivariable regression evaluated associations between intracranial injury type (temporal contusion [TC], frontal contusion, extraaxial [epidural/subdural/subarachnoid], other-intraaxial [intracerebral/intraventricular hemorrhage, axonal injury]) and GOSE. Odds ratios (OR) are reported.

RESULTS

Overall, 260 MTBI subjects were aged 44.4 ± 18.1-years; 67.7% were male. Ninety-seven subjects were CT-positive and 46 had contusions (41.3%-frontal, 30.4%-temporal, 21.7%-frontal + temporal, 2.2% each-parietal/occipital/brainstem); 95.7% had concurrent extraaxial hemorrhage. Mortality was 0% at discharge and 2.3% by 6-months. GOSE distribution was 2.3%-death, 1.5%-severe disability, 27.7%-moderate disability, 68.5%-good recovery. Forty-six percent of TC-positive subjects suffered moderate disability or worse (GOSE ≤6) and 41.7% were unable to return to baseline work capacity (RTBWC), compared to 29.1%/20.4% for CT-negative and 26.1%/20.9% for CT-positive subjects without TC. On multivariable regression, TC associated with OR = 3.33 (95% CI [1.16-9.60], p = 0.026) for GOSE ≤6, and OR = 4.48 ([1.49-13.51], p = 0.008) for inability to RTBWC.

CONCLUSIONS

Parenchymal contusions in MTBI are often accompanied by extraaxial hemorrhage. TCs may be associated with 6-month functional impairment. Their presence on imaging should alert the clinician to the need for heightened surveillance of sequelae complicating RTBWC, with low threshold for referral to services.

Extensive perineural spread of an intrapelvic sciatic malignant peripheral nerve sheath tumor: a case report

Perineural spread has been described in multiple neoplasms of neural and non-neural origin. The peripheral nervous system may represent a highway by which tumors can spread throughout the body. Malignant peripheral nerve sheath tumor (MPNST) is a neoplasm arising from peripheral nerves with high rates of local recurrence and distant metastases, leading to a poor 5-year overall survival. In many cases, the optimal treatment involves wide en bloc excision with negative margins as well as chemotherapy and radiation. Even in cases of negative surgical margins, recurrence rates are high, suggesting possible skip lesions or very distant infiltration along the involved nerve. We report a case of high-grade MPNST of the sciatic nerve with post-mortem dissection and histopathologic characterization of perineural spread of microscopic disease to sites significantly proximal and distal to areas with evidence of gross disease, which may help to explain the high rates of local and distal recurrence in MPNST.

Low-Grade Malignant Peripheral Nerve Sheath Tumor Mimicking Schwannoma: Role and Importance of Trimethylated H3K27M Staining

BACKGROUND

It is important to differentiate low-grade malignant peripheral nerve sheath tumors (MPNSTs) from benign nerve sheath tumors as MPNSTs may require a more aggressive treatment strategy during and after initial resection. Loss of expression of the trimethyl histone H3 at the Lys27 position (H3K27-me3) has recently been described in MPNSTs and may help distinguish this tumor from pathologic mimics.

METHODS

A 43-year-old woman presented with symptoms of radiculopathy and a history of pelvic radiation for cervical cancer 7 years prior. Imaging and surgical pathology were initially consistent with an L5 schwannoma including spindle morphology without mitoses and retained S100 expression. After an aggressive recurrence 11 months later, pathology was consistent with high-grade MPNST including heightened mitotic activity and loss of S100 expression.

RESULTS

After the identification of MPNST, H3K27M me3 immunostaining was applied to both the initial and recurrent pathologic specimens. The initial specimen demonstrated patchy loss of H3K27M me3 expression, more consistent with low-grade MPNST than schwannoma.

CONCLUSION

This case highlights the role of H3K27M me3 immunostaining to help differentiate MPNSTs that may mimic more benign nerve sheath tumors, especially in patients who have a history of radiation to the region in question.

Laminotomy for Lumbar Dorsal Root Ganglion Access and Injection in Swine

Dorsal root ganglia (DRG) are anatomically well defined structures that contain all primary sensory neurons below the head. This fact makes DRG attractive targets for injection of novel therapeutics aimed at treating chronic pain. In small animal models, laminectomy has been used to facilitate DRG injection because it involves surgical removal of the vertebral bone surrounding each DRG. We demonstrate a technique for intraganglionic injection of lumbar DRG in a large animal species, namely, swine. Laminotomy is performed to allow direct access to DRG using standard neurosurgical techniques, instruments, and materials. Compared with more extensive bone removal via laminectomy, we implement laminotomy to conserve spinal anatomy while achieving sufficient DRG access. Intraoperative progress of DRG injection is monitored using a non-toxic dye. Following euthanasia on post-operative day 21, the success of injection is determined by histology for intraganglionic distribution of 4',6-diamidino-2-phenylindole (DAPI). We inject a biologically inactive solution to demonstrate the protocol. This method could be applied in future preclinical studies to target therapeutic solutions to DRG. Our methodology should facilitate testing the translatability of intraganglionic small animal paradigms in a large animal species. Additionally, this protocol may serve as a key resource for those planning preclinical studies of DRG injection in swine.

Deadly falls: operative versus nonoperative management of Type II odontoid process fracture in octogenarians

OBJECTIVE

Type II odontoid fracture is a common injury among elderly patients, particularly given their predisposition toward low-energy falls. Previous studies have demonstrated a survival advantage following early surgery among patients older than 65 years, yet octogenarians represent a medically distinct and rapidly growing population. The authors compared operative and nonoperative management in patients older than 79 years.

METHODS

A single-center prospectively maintained trauma database was reviewed using ICD-9 codes to identify octogenarians with C-2 cervical fractures between 1998 and 2014. Cervical CT images were independently reviewed by blinded neurosurgeons to confirm a Type II fracture pattern. Prospectively recorded outcomes included Glasgow Coma Scale (GCS) score, Abbreviated Injury Scale (AIS) score, Injury Severity Score (ISS), additional cervical fracture, and cord injury. Primary end points were mortality at 30 days and at 1 year. Statistical tests included the Student t-test, chi-square test, Fisher's exact test, Kaplan-Meier test, and Cox proportional hazard.

RESULTS

A total of 111 patients met inclusion criteria (94 nonoperative and 17 operative [15 posterior and 2 anterior]). Mortality data were available for 100% of patients. The mean age was 87 years (range 80–104 years). Additional cervical fracture, spinal cord injury, GCS score, AIS score, and ISS were not associated with either management strategy at the time of presentation. The mean time to death or last follow-up was 22 months (range 0–129 months) and was nonsignificant between operative and nonoperative groups (p = 0.3). Overall mortality was 13% in-hospital, 26% at 30 days, and 41% at 1 year. Nonoperative and operative mortality rates were not significant at any time point (12% vs 18%, p = 0.5 [in-hospital]; 27% vs 24%, p = 0.8 [30-day]; and 41% vs 41%, p = 1.0 [1-year]). Kaplan-Meier analysis did not demonstrate a survival advantage for either management strategy. Spinal cord injury, GCS score, AIS score, and ISS were significantly associated with 30-day and 1-year mortality; however, Cox modeling was not significant for any variable. Additional cervical fracture was not associated with increased mortality. The rate of nonhome disposition was not significant between the groups.

CONCLUSIONS

Type II odontoid fracture is associated with high morbidity among octogenarians, with 41% 1-year mortality independent of intervention—a dramatic decrease from actuarial survival rates for all 80-, 90-, and 100-year-old Americans. Poor outcome is associated with spinal cord injury, GCS score, AIS score, and ISS.

Liposomal bupivacaine incisional injection in single-level lumbar spine surgery

BACKGROUND CONTEXT

Postsurgical pain control is important in spine surgery as it can lead to earlier mobilization, decreased length of stay, decreased side effects from narcotic medications, and improved patient satisfaction. Liposomal bupivacaine (LB) is an injectable formulation of bupivacaine, providing prolonged local anesthesia, up to 72 hours postinjection. Although, LB has been used with increasing frequency following other musculoskeletal procedures, specifically total joint replacements, its pre-emptive analgesic effect following lumbar microdiscectomy has hitherto not been reported. If administration of LB as a pre-emptive analgesic agent at the end of microdiscectomy resulted in reduced postoperative pain, then this could minimize adverse events related to narcotic pain medication use and improve acute clinical outcomes.

PURPOSE

The aim of the present study was to determine the comparative efficacy of infiltration of a standard dose and volume of LB in a comparative cohort analysis of single-level microdiscectomy procedures.

DESIGN

The present study made use of mixed prospective/retrospective observational cohort analysis.

PATIENT SAMPLE

Adult patients presenting with lumbar or sacral compressive disc disease treated with single-level microdiscectomy, at one institution utilizing a standard surgical technique.

OUTCOME MEASURES

Time spent on intravenous (IV) narcotics postoperatively (primary outcome), postoperative visual analog score (VAS), total morphine equivalent dose of narcotic pain medications, and 30-day emergency room visits for pain control were measured.

METHODS

Under an approved process improvement project, immediate outcome and process measures for a prospective cohort of 40 patients who received LB field blocks following single-level lumbar microdiscectomy were compared with a historical cohort of 40 patients who underwent the same surgical procedure but did not receive postsurgical infiltration of local anesthetic. All patients received a standard open surgical technique and postoperative convalescence protocol, which included overnight admission, oral narcotic pain medication as needed, scheduled IV ketorolac and IV narcotic pain medication for breakthrough.

RESULTS

Data from 80 subjects (67 males) operated on between January 2014 and 2015 were compared, including 40 cases, which occurred prior to using LB, and 40 cases after. There was no significant difference between mean age or body mass index (BMI) between groups. Patients who received LB infiltration spent significantly less time using IV narcotics in the postoperative period (LB patients 13.0±2.1 hours vs. non-LB patients 23.3±2.1 hours, p<.001). There was no significant difference noted between VAS at any point in the postoperative period, total injectable morphine equivalent doses, or 30-day emergency room visits for pain.

CONCLUSIONS

We found that patients who received LB field blocks required IV narcotic pain medication for a significantly decreased length of time (average delta=10.3 hours). Although this is a surrogate for earlier discharge, within the numbers studied, this did not translate into a significantdifference in VAS scores or total morphine equivalents. It is uncertain, if the independent effect of LB may have been masked by the multimodal postoperative pain control protocol in use. Further study is required to best understand the potential benefit of pre-emptive analgesia in elective spine surgery. Its impact would likely be more significant in more invasive procedures.

Flow Diversion for Ophthalmic Artery Aneurysms

Endovascular treatments of ophthalmic segment aneurysms are commonly used but visual outcomes remain a concern. We performed a retrospective review of patients with carotid-ophthalmic aneurysms treated with flow diversion from June 2009 to June 2015. The following outcomes were studied through chart review: visual outcomes, complications, postoperative stroke and intraparenchymal hemorrhage, and clinical outcomes. Angiographic outcomes were studied with angiography and MRA at 6 months, 1 year, and 3 years. We evaluated 50 carotid-ophthalmic aneurysms in 48 patients, among whom 44 patients with 46 aneurysms underwent treatment. The mean clinical follow-up was 29 ± 22 months (range, 0-65 months). There were no permanent adverse visual outcomes. There was 1 death because of late intraparenchymal hemorrhage (2.2%). Six-month angiography showed complete occlusion in 24 of 37 patients (64.9%), and 3-year angiography results showed occlusion in 24 of 25 patients (96%). In conclusion, flow diversion is a safe and effective treatment for carotid-ophthalmic aneurysms in carefully selected patients. The risk of adverse visual outcomes is low, and most aneurysms progress to complete occlusion.

Delayed cerebral infarct following anterior cervical diskectomy and fusion

Background:

Ischemic stroke following anterior cervical diskectomy and fusion (ACDF) is an exceedingly rare complication. There are only three previous cases focusing on this problem in the literature; here, we present the fourth case.

Case Description:

A patient, cared for at an outside institution, developed a delayed ischemic stroke 3 days following an ACDF. This complication was attributed to carotid manipulation precipitating vascular injury in the setting of multiple comorbid vascular and coagulopathic risk factors, including previously undiagnosed carotid atherosclerosis, a prior history of pulmonary embolus requiring Warfarin anticoagulation (held perioperatively), acute dehydration, and atrial fibrillation.

Conclusions:

This case demonstrates the importance of focused history and examination in appropriate patients prior to ACDF, with special consideration given to the significance of age, comorbidities including coagulopathy and arrhythmia, and potential underlying vascular disease as markers for increased risk of perioperative thrombotic stroke associated with carotid manipulation. Patients at higher risk warrant comprehensive preoperative assessment, including medical evaluation, carotid imaging, and consideration for alternative surgical approaches.

Postoperative Delayed Cervical Palsies: Understanding the Etiology

STUDY DESIGN

Retrospective study.

OBJECTIVE

This study reviews 1,768 consecutive cervical decompressions with or without instrumented fusion to identify patient-specific and procedural risk factors significantly correlated with the development of delayed cervical palsy (DCP).

METHODS

Baseline demographic and procedural information was collected from the electronic medical record. Particular attention was devoted to reviewing each chart for recognized risk factors of postsurgical inflammatory neuropathy: autoimmune disease, blood transfusions, diabetes, and smoking.

RESULTS

Of 1,669 patients, 56 (3.4%) developed a DCP. Although 71% of the palsies involved C5, 55% of palsies were multimyotomal and 18% were bilateral. Significant risk factors on univariate analysis included age (p = 0.0061, odds ratio [OR] = 1.07, 95% confidence interval [CI] 1.008 to 1.050), posterior instrumented fusion (p < 0.0001, OR = 3.30, 95% CI 1.920 to 5.653), prone versus semisitting/sitting position (p = 0.0036, OR = 3.58, 95% CI 1.451 to 11.881), number of operative levels (p < 0.0001, OR = 1.42, 95% CI 1.247 to 1.605), intraoperative transfusions (p = 0.0231, OR = 2.57, 95% CI 1.152 to 5.132), and nonspecific autoimmune disease (p = 0.0107, OR = 3.83, 95% CI 1.418 to 8.730). On multivariate analysis, number of operative levels (p = 0.0053, OR = 1.27, 95% CI 1.075 to 1.496) and nonspecific autoimmune disease (p = 0.0416, OR 2.95, 95% CI 1.047 to 7.092) remained significant.

CONCLUSIONS

Although this study partially supports a mechanical etiology in the pathogenesis of a DCP, we also describe a notable correlation with autoimmune risk factors. Bilateral and multimyotomal involvement provides additional support that some DCPs may result from an inflammatory response and thus an underlying multifactorial etiology for this complication.

Patient and Procedural Factors That Influence Anesthetized, Nonoperative Time in Spine Surgery

STUDY DESIGN

Retrospective study.

OBJECTIVE

Efficient use of operating room time is important, as delays during induction or recovery increase time not spent operating while in the operating room. We identified factors that increase anesthetized, nonoperative time by utilizing a database of over 5,000 consecutive neurosurgical spine cases.

METHODS

Surgical records were searched to identify all spine surgeries performed between January 2010 and July 2012. Anesthetized, nonoperative time was calculated from the anesthesia record and compared with both patient and procedure characteristics to determine any significant relationships.

RESULTS

There were 5,515 surgical cases with a mean age of 60.5 and mean body mass index (BMI) of 29.7; 3,226 (58%) were male subjects. There were 1,176 (21%) fusion cases, and level of pathology was predominantly lumbar (4,010 cases, 73%). Fusion cases had a significantly longer total anesthetized, nonoperative time (fusion: 98 minutes, nonfusion: 76 minutes, mean difference: 22 minutes, p < 0.0001). Significant factors affecting anesthetized, nonoperative time in nonfusion cases include age greater than 65 years (mean difference 5 minutes, p < 0.0001), American Society of Anesthesiologists (ASA) grade, and BMI (BMI < 25: 72 ± 1.2 minutes, BMI 25 to 29: 74 ± 0.6 minutes, BMI 30 to 39: 79 ± 0.6 minutes, BMI 40 + : 87 ± 1.8 minutes, p < 0.0001). Similarly, for fusion operations, age > 65 years significantly increased nonoperative time (mean difference 6 minutes, p < 0.01), as did increasing ASA (mean difference 9 minutes, p < 0.0001) and increasing BMI.

CONCLUSION

Patient and surgical factors, including ASA grade, BMI, level of pathology, and surgical approach, have noticeable effects on anesthetized, nonoperative times in spine surgery.

Understanding the Impact of Obesity on Short-term Outcomes and In-hospital Costs After Instrumented Spinal Fusion

BACKGROUND

Obesity rates continue to rise along with the number of obese patients undergoing elective spinal fusion.

OBJECTIVE

To evaluate the impact of obesity on resource utilization and early complications in patients undergoing surgery for degenerative spine disease.

METHODS

A single-institution retrospective analysis was conducted on patients with degenerative spine disease requiring instrumentation between 2008 and 2012. The 801 identified patients were grouped based on a body mass index (BMI) of <30 (nonobese, n = 478), ≥30 and <40 (obese, n = 283), and alternatively BMIs of ≥40 (morbidly obese, n = 40). Baseline characteristics, surgical outcomes and requirements, complications, and cost were compared. Logistic and linear regression analyses were used to determine the strength of association between obesity and outcomes for categorical and continuous data, respectively.

RESULTS

Significant differences were found in comorbidities between cohorts. Multivariate analysis revealed significant associations between obesity and longer anesthesia times (30 minutes, P = .008), and surgical times (24 minutes, P = .02). Additionally, there was a 2.8 times higher rate of wound complications in obese patients (4.2% vs 1.5, P = .03), and 2.5 times higher rate of major medical complications (7.8% vs 3.1, P = .01). Morbid obesity resulted in a 10 times higher rate of wound complications (P < .001). Morbid obesity resulted in a $9078 (P = .005) increase in overall cost of care.

CONCLUSION

Increased BMI is associated with longer operative times, increased complication rates, and increased cost independent of comorbidities. These effects are more pronounced with morbidly obese patients, further supporting a role for preoperative weight loss.

Patient-specific factors affecting hospital costs in lumbar spine surgery

OBJECT

Health care-related costs after lumbar spine surgery vary depending on procedure type and patient characteristics. Age, body mass index (BMI), number of spinal levels, and presence of comorbidities probably have significant effects on overall costs. The present study assessed the impact of patient characteristics on hospital costs in patients undergoing elective lumbar decompressive spine surgery.

METHODS

This study was a retrospective review of elective lumbar decompression surgeries, with a focus on specific patient characteristics to determine which factors drive postoperative, hospital-related costs. Records between January 2010 and July 2012 were searched retrospectively. Only elective lumbar decompressions including discectomy or laminectomy were included. Cost data were obtained using a database that allows standardization of a list of hospital costs to the fiscal year 2013–2014. The relationship between cost and patient factors including age, BMI, and American Society of Anesthesiologists (ASA) Physical Status Classification System grade were analyzed using Student t-tests, ANOVA, and multivariate regression analyses.

RESULTS

There were 1201 patients included in the analysis, with a mean age of 61.6 years. Sixty percent of patients in the study were male. Laminectomies were performed in 557 patients (46%) and discectomies in 644 (54%). Laminectomies led to an increased hospital stay of 1.4 days (p < 0.001) and increased hospital costs by $1523 (p < 0.001) when compared with discectomies. For laminectomies, age, BMI, ASA grade, number of levels, and durotomy all led to significantly increased hospital costs and length of stay on univariate analysis, but ASA grade and presence of a durotomy did not maintain significance on multivariate analysis for hospital costs. For a laminectomy, patient age ≥ 65 years was associated with a 0.6-day increased length of stay and a $945 increase in hospital costs when compared with patient age < 65 years (p < 0.001). A durotomy during a laminectomy increased length of stay by 1.0 day and increased hospital costs by $1382 (p < 0.03). For discectomies, age, ASA grade, and durotomy were significantly associated with increased hospital costs on univariate analysis, but BMI was not. Only age and presence of a durotomy maintained significance on multivariate analysis. There was a significant increase in hospital length of stay in patients undergoing discectomy with increasing age, BMI, ASA grade, and presence of a durotomy on univariate analysis. However, only age and presence of a durotomy maintained significance on multivariate analysis. For discectomies, age ≥ 65 years was associated with a 0.7-day increased length of stay (p < 0.001) and an increase of $931 in postoperative hospital costs (p < 0.01) when compared with age < 65 years.

CONCLUSIONS

Patient factors such as age, BMI, and comorbidities have significant and measurable effects on the postoperative hospital costs of elective lumbar decompression spinal surgeries. Knowledge of how these factors affect costs will become important as reimbursement models change.