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John K. Houten, Joshua R. Buksbaum, and Michael J. Collins

OBJECTIVE

Paresis of the C5 nerve is a well-recognized complication of cervical spine surgery. Numerous studies have investigated its incidence and possible causes, but the specific pattern and character of neurological deficits, time course, and relationship to preoperative cord signal changes remain incompletely understood.

METHODS

Records of patients undergoing cervical decompressive surgery for spondylosis, disc herniation, or ossification of the longitudinal ligament, including the C4–5 level, were reviewed from a 15-year period, identifying C5 palsy cases. Data collected included age, sex, diabetes and smoking statuses, body mass index, surgical levels, approach, presence of increased cord signal intensity, and modified Japanese Orthopaedic Association (mJOA) scores. Narrative descriptions of the patterns and findings on neurological examination were reviewed, and complications were noted. The minimum follow-up requirement for the study was 12 months.

RESULTS

Of 642 patients who underwent cervical decompressive surgery, 18 developed C5 palsy (2.8%). The incidence was significantly lower following anterior surgery (6 of 441 [1.4%]) compared with that following cervical laminectomy and fusion (12 of 201 [6.0%]) (p < 0.001). There were 10 men and 8 women whose mean age was 66.7 years (range 54–76 years). The mean preoperative mJOA score of 11.4 improved to 15.6 at the latest follow-up examination. There were no differences between those with and without C5 palsy with regard to sex, age, number of levels treated, or pre- or postoperative mJOA score. Fifteen patients with palsy (83%) had signal changes/myelomalacia on preoperative T2-weighted imaging, compared with 436 of 624 (70%) patients without palsy; however, looking specifically at the C4–5 level, signal change/myelomalacia was present in 12 of 18 (67%) patients with C5 palsy, significantly higher than in the 149 of 624 (24%) patients without palsy (p < 0.00003). Paresis was unilateral in 16 (89%) and bilateral in 2 (11%) patients. All had deltoid weakness, but 15 (83%) exhibited new biceps weakness, 8 (44%) had triceps weakness, and 2 (11%) had hand intrinsic muscle weakness. The mean time until onset of palsy was 4.6 days (range 2–14 days). Two patients (11%) complained of shoulder pain preceding weakness; 3 patients (17%) had sensory loss. Recovery to grade 4/5 deltoid strength occurred in 89% of the patients. No patient had intraoperative loss of somatosensory or motor evoked potentials or abnormal intraoperative C5 electromyography activity.

CONCLUSIONS

Postoperative C5 nerve root dysfunction appears in a delayed fashion, is predominantly a motor deficit, and weakness is frequently appreciated in the biceps and triceps muscles in addition to the deltoid muscle. Preoperative cord signal change/myelomalacia at C4–5 was a significant risk factor. No patient had a detectable deficit in the immediate postoperative period or changes in intraoperative neuromonitoring status. Neurological recovery to at least that of grade 4/5 occurred in nearly 90% of the patients.

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John K. Houten, Gila R. Weinstein, Michael J. Collins, and Daniel Komlos

OBJECTIVE

Wound complications such as surgical site infection (SSI) and dehiscence are among the most common complications of thoracolumbar spinal fusion surgery and are particularly prevalent in patients with risk factors such as obesity, diabetes, smoking, malignancy, and multilevel and/or revision procedures. A specialized wound closure technique with muscle flap mobilization, which reduces tension at the wound edges and increases the bulk of vascularized tissue in the midline, can be employed as a salvage procedure to manage wound complications. The authors evaluated the effectiveness of prophylactic muscle flap closure for reducing SSI in patients with risk factors for wound complications who undergo thoracolumbar fusion surgery.

METHODS

A retrospective review of thoracolumbar fusion surgeries over a 15-year period was conducted in a group of patients at risk for wound complications to compare outcomes of patients who underwent prophylactic muscle flap closure with outcomes of patients who had conventional wound closure. Patients were selected for specialized closure based upon a protocol adopted during the study period. Patients were excluded if they had active infections or underwent tubular retractor–mediated decompression and did not have open surgery with a midline incision.

RESULTS

Of 716 patients, wound closure was performed in 455 patients using conventional closure and in 261 using muscle flap closure. There were no significant differences in the ratios of male to female patients, with 251 men and 204 women with conventional closure and 133 men and 128 women with muscle flap closure, but the muscle flap patients were older than the conventional closure patients, with mean ages of 65.2 versus 62.9 years (p < 0.005). Indications for surgery in the muscle flap group and the conventional group, respectively, were metastatic disease in 44 (17%) and 32 (7%) patients; trauma in 10 (4%) and 14 (3%) patients; and degenerative disease, including spondylolisthesis, spondylolysis, and stenosis, in 207 (79%) and 409 (90%) patients, with more muscle flap patients having metastasis (p < 0.00001). Patients having muscle flaps had significantly higher rates of diabetes, smoking, and revision surgery, and a higher mean BMI and number of operative levels. The serum albumin level was slightly lower in the muscle flap group (p < 0.047). The wound infection rate was significantly lower in the muscle flap group (0.4%) compared with the conventional closure group (2.4%) (p < 0.033).

CONCLUSIONS

Prophylactic muscle flap closure significantly lowers the rate of SSI in patients undergoing thoracolumbar spinal fusion who harbor risk factors for wound complications, with even fewer infections seen than in a group of patients without similar risk factors. Given the success of the technique, consideration of wider use for thoracolumbar fusion cases, even those without a high level of complexity, may be warranted.

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Shawn R. Eagle, Anish Puligilla, Vanessa Fazio-Sumrok, Nathan Kegel, Michael W. Collins, and Anthony P. Kontos

OBJECTIVE

No studies to date have investigated the role of early clinical care in time to recovery from concussion in a pediatric population. The purpose of this study was to investigate the role of clinic presentation timing (≤ 7 days [early] compared to 8–20 days [late] from injury) in concussion assessment performance and risk for prolonged recovery (> 30 days) in pediatric concussion.

METHODS

This study is a retrospective cross-sectional study from a concussion clinic between April 2016 and January 2019, including 218 children and adolescents with diagnosed concussion, separated based on clinic presentation timing following injury: early (≤ 7 days) and late (8–20 days). Outcomes were recovery time, Postconcussion Symptom Scale (PCSS), Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT), Vestibular/Ocular Motor Screen (VOMS), and demographics, medical history, and injury information. A general linear model and chi-square analyses were used to assess differences between early and late presentation, along with logistic regression, to predict prolonged recovery (> 30 days).

RESULTS

Those with early presentation reported higher symptoms on VOMS subtests (79%–85%) compared to those with late presentation (61%–78%), with the exception of near-point of convergence distance and visual motion sensitivity (VMS). The strongest predictor of prolonged recovery was number of days to first clinic visit (OR 9.8). Positive VMS (OR 5.18), history of headache/migraine (OR 4.02), and PCSS score (OR 1.04) were also predictive of prolonged recovery.

CONCLUSIONS

Despite patients in the early presentation group presenting with more positive VOMS scores, the early presentation group recovered sooner than patients in the late presentation group. Even after controlling for vestibular dysfunction, history of headache or migraine, and total symptom severity, days to first visit remained the most robust predictor of recovery > 30 days. These findings suggest that early, specialized medical care and intervention for children and adolescents with recent concussion is associated with normal recovery time. Clinicians should educate children and parents on the potential importance of early treatment to improve the odds of positive outcomes following concussion.

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Jason P. Mihalik, Jamie E. Stump, Michael W. Collins, Mark R. Lovell, Melvin Field, and Joseph C. Maroon

Object. The object of this study was to compare symptom status and neurocognitive functioning in athletes with no headache (non-HA group), athletes complaining of headache (HA group), and athletes with characteristics of posttraumatic migraine (PTM group).

Methods. Neurocognitive tests were undertaken by 261 high-school and collegiate athletes with a mean age of 16.36 ± 2.6 years. Athletes were separated into three groups: the PTM group (74 athletes with a mean age of 16.39 ± 3.06 years), the HA group (124 athletes with a mean age of 16.44 ± 2.51 years), and the non-HA group (63 patients with a mean age of 16.14 ± 2.18 years). Neurocognitive summary scores (outcome measures) for verbal and visual memory, visual motor speed, reaction time, and total symptom scores were collected using ImPACT, a computer software program designed to assess sports-related concussion.

Significant differences existed among the three groups for all outcome measures. The PTM group demonstrated significantly greater neurocognitive deficits when compared with the HA and non-HA groups. The PTM group also exhibited the greatest amount of departure from baseline scores.

Conclusions. The differences among these groups can be used as a basis to argue that PTM characteristics triggered by sports-related concussion are related to increased neurocognitive dysfunction following mild traumatic brain injury. Thus, athletes suffering a concussion accompanied by PTM should be examined in a setting that includes symptom status and neurocognitive testing to address their recovery more fully. Given the increased impairments observed in the PTM group, in this population clinicians should exercise increased caution in decisions about treatment and when the athlete should be allowed to return to play.

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Shawn R. Eagle, Lisa Manderino, Michael Collins, Nathan Kegel, Vanessa Fazio-Sumrok, Anne Mucha, and Anthony P. Kontos

OBJECTIVE

The aim of this study was to analyze the best combination of clinical variables associated with concussion subtypes using a multidomain assessment comprising medical history; symptoms; and cognitive, ocular, and vestibular impairment in a cohort of patients presenting to a concussion specialty clinic.

METHODS

Adolescent patients (n = 293) completed demographics and medical history, Concussion Clinical Profiles Screening, Immediate Post-Concussion Assessment and Cognitive Testing, and vestibular ocular motor screening at their first visit (mean 7.6 ± 7.8 days postinjury) to a concussion specialty clinic. Each participant was adjudicated to have one or more subtype (anxiety/mood, cognitive, migraine, ocular, and vestibular) by a healthcare professional based on previously published criteria. A series of backward, stepwise logistic regressions were used to identify significant predictors of concussion subtypes, and predictive probabilities from the logistic regression models were entered into area under the receiver operating characteristic curve (AUC) models.

RESULTS

Each of 5 logistic regression models predicting primary subtypes accounted for 28%–50% of the variance (R2 = 0.28–0.50, p < 0.001) and included 2–8 significant predictors per model. Each of the models significantly differentiated the primary subtype from all other subtypes (AUC = 0.76–0.94, p < 0.001).

CONCLUSIONS

These findings suggest that each concussion subtype can be identified using specific outcomes from a multidomain assessment. Clinicians can employ such an approach to better identify and monitor recovery from subtypes as well as guide interventions.

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Merrill J. Egorin, Edwin H. Bellis, Michael Salcman, Jerry M. Collins, James F. Spiegel, and Nicholas R. Bachur

✓ Diaziquone (also called “aziridinyl benzoquinone,” or AZQ), an antitumor drug designed to penetrate the blood-brain barrier, has demonstrated activity against central nervous system (CNS) neoplasms. Four-hour infusions of carbon-14 (14C)-labeled AZQ (0.8 mg/kg) were given via the left common carotid artery or left brachial vein to two groups of puppies. A third group, harboring a transplantable canine glioma, received 14C-AZQ by intravenous infusion. Levels of chloroform (CHCl3)-extractable 14C (AZQ only) and total 14C (AZQ and metabolites) were determined in serial samples of plasma and cerebrospinal fluid (CSF). At the end of the infusion time, total and CHCl3-extractable 14C levels were determined in brain and tumor. Intra-arterial infusion of AZQ caused no histological abnormalities in the retina or brain. For the intravenous infusion group, the concentrations of CHCl3-extractable 14C (in nmol/ml or nmol/gm) were 0.68, 0.35, and 0.84 for plasma, brain, and CSF, respectively. For the intra-arterial infusion group, the concentrations were 0.25, 0.13, and 0.32 for plasma, brain, and CSF, respectively.

Comparison of right and left hemispheres following intra-arterial infusion showed a slightly higher concentration of 14C in the ipsilateral (left) hemisphere, with concentrations (nmol/gm) of CHCl3-extractable 14C/total 14C of 0.15/0.87 on the left and 0.12/0.65 on the right. Concentrations (nmol/gm) of CHCl3-extractable 14C/total 14C in brain and tumor were 0.60/1.24 and 0.58/1.65, respectively. In tumor-bearing animals, tumor and surrounding brain contained similar concentrations of AZQ, but there were higher concentrations of metabolites in tumor. This may reflect different metabolism of AZQ within brain and tumor or different permeability to metabolites. This study revealed that AZQ enters the CNS and brain-tumor tissue in substantial concentrations and that there is no significant advantage to intracarotid infusion of AZQ.

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Céline Amiez, Penelope Kostopoulos, Anne-Sophie Champod, D. Louis Collins, Julien Doyon, Rolando Del Maestro, and Michael Petrides

Object

Resection of brain tumors has been shown to increase patient survival. The extent of the possible resection, however, depends on whether the tumor has invaded brain regions important for motor, sensory, or cognitive processes and whether the brain tissue surrounding the tumor maintains its functional role. The goal of the present study was to develop new pre- and intraoperative tools to specifically assess the function of the rostral part of the dorsal premotor cortex (PMdr) in 4 patients with brain tumors close to this region.

Methods

Using functional magnetic resonance (fMR) imaging and a task developed to assess accurate selection between competing responses based on conditional rules, the authors preoperatively assessed the function of the PMdr in 4 patients with brain tumors close to this region. In 1 patient, the authors developed an intraoperative procedure to assess performance on the task during the tumor resection.

Results

Preoperative fMR imaging data showed specific activity increases in the vicinity of the tumors, that is, in the PMdr. As confirmed by postoperative structural MR imaging, the extent of the tumor resection was optimal and the functional region within the PMdr was preserved. Furthermore, patients exhibited no postoperative deficits during task performance, demonstrating that the function was preserved. Intraoperative behavioral results demonstrated that the cognitive processes underlying performance on the task remained intact throughout the tumor resection.

Conclusions

These findings suggest that preoperative fMR imaging, together with intraoperative behavioral evaluation, may be a useful paradigm to assist neurosurgeons in preserving cognitive function in patients with brain tumors.

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Mark R. Lovell, Michael W. Collins, Grant L. Iverson, Melvin Field, Joseph C. Maroon, Robert Cantu, Kenneth Podell, John W. Powell, Mark Belza, and Freddie H. Fu

Object. A computerized neuropsychological test battery was conducted to evaluate memory dysfunction and self-reporting of symptoms in a group of high school athletes who had suffered concussion.

Methods. Neuropsychological performance prior to and following concussion was compared with the test performance of an age-matched control group. Potentially important diagnostic markers of concussion severity are discussed and linked to recovery within the 1st week of injury.

Conclusions. High school athletes who had suffered mild concussion demonstrated significant declines in memory processes relative to a noninjured control group. Statistically significant differences between preseason and postinjury memory test results were still evident in the concussion group at 4 and 7 days postinjury. Self-reported neurological symptoms such as headache, dizziness, and nausea resolved by Day 4. Duration of on-field mental status changes such as retrograde amnesia and posttraumatic confusion was related to the presence of memory impairment at 36 hours and 4 and 7 days post-injury and was also related to slower resolution of self-reported symptoms. The results of this study suggest that caution should be exercised in returning high school athletes to the playing field following concussion. On-field mental status changes appear to have prognostic utility and should be taken into account when making return-to-play decisions following concussion. Athletes who exhibit on-field mental status changes for more than 5 minutes have longer-lasting postconcussion symptoms and memory decline.

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Daniel M. Sciubba, Rory J. Petteys, Sophia F. Shakur, Ziya L. Gokaslan, Edward F. McCarthy, Michael T. Collins, Matthew J. McGirt, Patrick C. Hsieh, Clarke S. Nelson, and Jean-Paul Wolinsky

En bloc spondylectomy represents a radical resection of a spinal segment most often reserved for patients presenting with a primary extradural spine tumor or a solitary metastasis in the setting of an indolent, well-controlled systemic malignancy. The authors report a case in which en bloc spondylectomy was conducted to control a metabolically active spine tumor. A 56-year-old woman, who suffered from severe tumor-induced osteomalacia, was found to have a fibroblast growth factor-23–secreting phosphaturic mesenchymal tumor in the T-8 vertebral body. En bloc resection was conducted, leading to resolution of her tumor-induced osteomalacia. This case suggests that radical spondylectomy may be beneficial in the management of metabolically or endocrinologically active tumors of the spine.