Intraoperative discovery of a radiographically occult subependymoma obstructing the obex in a patient with a Chiari malformation - A rare case.

Background: Chiari (type I) malformations are typically congenital. Occasionally, however, tonsillar herniation can arise secondary to cerebrospinal fluid leakage, posterior fossa or intraventricular mass lesions, or other etiologies. We present the first-ever case of an intramedullary subependymoma at the cervicomedullary junction associated with vertebral bone abnormalities and an acquired secondary Chiari malformation. Case Description: A 60-year-old woman presented with a 3-year history of occipital, tussive headaches. Preoperative imaging was negative for mass lesions but demonstrated a Chiari malformation. She was recommended posterior fossa decompression with tonsillar shrinkage. During surgery, an intramedullary mass was incidentally observed, obstructing the obex at the cervicomedullary junction. Histopathological analysis of the resected lesion revealed a diagnosis of subependymoma. Conclusion: Subependymomas can sometimes present a diagnostic challenge due to their subtle appearance in neuroimaging. Only rarely are such masses associated with an acquired Chiari malformation. No such case has previously been reported. We present a literature review on acquired Chiari malformations and discuss their management.

Cervicomedullary junction mature teratoma with pulmonary differentiation and diastematomyelia in an adult - A rare case.

Background: Intradural extramedullary teratomas in the cervical or cervicomedullary region are rare in adults. Case Description: We report a symptomatic, mature teratoma at the cervicomedullary junction in a 52-year-old Hispanic female who also has a type I diastematomyelia in the thoracolumbar spine. The patient underwent surgical resection of the lesion with the resolution of presenting symptoms. Histopathology of the lesion revealed a mature cystic teratoma with pulmonary differentiation. Conclusion: We discuss the case along with a review of pertinent literature and considerations with regard to the diagnosis, etiology, prognosis, and management of this unusual pathology.

Mechanical failure of the Mobi-C implant for artificial cervical disc replacement: report of 4 cases.

Cervical spondylosis is one of the most commonly treated conditions in neurosurgery. Increasingly, cervical disc replacement (CDR) has become an alternative to traditional arthrodesis, particularly when treating younger patients. Thus, surgeons continue to gain a greater understanding of short- and long-term complications of arthroplasty. Here, the authors present a series of 4 patients initially treated with Mobi-C artificial disc implants who developed postoperative neck pain. Dynamic imaging revealed segmental kyphosis at the level of the implant. All implants were locked in the flexion position, and all patients required reoperation. This is the first reported case series of symptomatic segmental kyphosis after CDR.

The combined administration of vancomycin IV, standard prophylactic antibiotics, and vancomycin powder in spinal instrumentation surgery: does the routine use affect infection rates and bacterial resistance?

BACKGROUND: Surgical site infections (SSI) poses significant risk following spinal instrumentation surgery. The 2013 North American Spine Society (NASS) Evidence-Based Clinical Guidelines found that the incidence of SSI in spine surgery ranged from 0.7-10%, with higher rates with medical comorbidities. National guidelines currently recommend first-generation cephalosporins as first line prophylaxis. Due to an increase in MRSA cases in our institution, a combined antibiotic strategy using vancomycin IV, standard prophylactic antibiotics, and vancomycin powder was implemented for all spinal instrumentation surgeries. METHODS: All spinal instrumentation surgeries performed at this institution from 2013-2016 were identified. Chart review was then performed to identify the inclusion and exclusion criteria, demographic data, diagnosis, type of surgery performed, and bacterial culture results. Rates of SSI, as defined by the Center for Disease Control (CDC), were calculated and antibiotic resistance was determined. As control, SSIs were identified and reviewed from 2010, prior to the implementation of the combined strategy. RESULTS: One thousand and seventy four subjects were identified in the combined cohort. Mean age was 52.3 years, 540 males (50.2%), 534 females (49.8%). There were 960 primary surgeries (89.4%), 114 cases revision surgeries (10.6%). Cervical myelopathy (27.9%), lumbar stenosis (16.2%), lumbar spondylolisthesis (14.0%), and scoliosis (pediatric and adult)/deformity (13.7%) were leading diagnoses. The standard prophylactic antibiotic was cefazolin IV in 524 cases (48.8%), gentamicin IV in 526 cases (49.0%), vancomycin powder was used in 72.3% of cases. Four SSI cases out of 1,074 were identified (0.37%), 3 deep and 1 superficial, with no antibiotic resistance. In the control group, there were 11 infections of 892 cases (1.23%). There were significantly lower rates of SSI in the combined group versus control (P=0.05). CONCLUSIONS: The combined antibiotic strategy led to low SSI rates in this retrospective case control study. Limitations of this study include retrospective design and small sample size. A large multicenter randomized clinical trial may provide further insight in the effectiveness of this strategy. Level of evidence 3. Clinical relevance: the combined antibiotic protocol may be considered in institutions with concern for SSI and methicillin resistant infections associated with spinal instrumentation surgeries.

Hispanic and African American adult brain tumor patients treated at Harbor-UCLA Medical Center compared to Los Angeles County and Torrance, California.

The objective of this study is to shed light on racial disparities among Hispanic and African American adult brain tumor patients treated at Harbor-UCLA Medical Center compared to the general populations of Los Angeles County (LAC) and Torrance, California (CA). A retrospective review of patients admitted to the neurosurgery service at Harbor-UCLA Medical Center during years 2006 through 2010 was performed. Government census data was queried and pertinent national statistics were retrieved. Brain tumor patients at Harbor-UCLA were compared to the general populations of LAC and Torrance. A total of 271 patients were included in the study. The mean age was 46.9 years. Hispanics comprised the majority of neurosurgical patients (n = 151, 55.7%), followed by African Americans (n = 35, 12.9%). A greater percentage of Hispanic patients were treated at Harbor-UCLA relative to the general Hispanic populations of LAC and Torrance (p < .001). A greater percentage of African American patients were treated at Harbor-UCLA relative to the general African American populations of LAC and Torrance (p = .035 and p < .001, respectively). Our data revealed significant racial disparities amid the Harbor-UCLA Hispanic and African American patient populations compared to the general Angeleno populations of LAC and Torrance.

Skull fracture with effacement of the superior sagittal sinus following drone impact: a case report.

BACKGROUND: The popularity of unmanned aerial vehicles, or drones, raises safety concerns as they become increasingly common for commercial, personal, and recreational use. Collisions between drones and people may result in serious injuries. CASE REPORT: A 13-year-old male presented with a comminuted depressed skull fracture causing effacement of the superior sagittal sinus secondary to a racing drone impact. The patient experienced a brief loss of consciousness and reported lower extremity numbness and weakness after the accident. Imaging studies revealed bone fragments crossing the superior sagittal sinus with a short, focal segment of blood flow interruption. Neurosurgical intervention was deferred given the patient's improving neurological deficits, and the patient was treated conservatively. He was discharged home in stable condition. CONCLUSION: Drones may represent a hazard when operated inappropriately due to their capacity to fly at high speeds and altitudes. Impacts from drones can carry enough force to cause skull fractures and significant head injuries. The rising popularity of drones likely translates to an increased incidence of drone-related injuries. Thus, clinicians should be aware of this growing trend.

Quantitative Data-driven Utilization of Hematologic Labs Following Lumbar Fusion.

STUDY DESIGN: Retrospective case series. SUMMARY OF BACKGROUND DATA: Large national inpatient databases estimate that approximately 200,000 lumbar fusions are performed annually in the United States alone. It is common for surgeons to routinely order postoperative hematologic studies to rule out postoperative anemia despite a paucity of data to support routine laboratory utilization. OBJECTIVE: To describe quantitative criteria to guide postoperative utilization of hematologic laboratory assessments. METHODS: A retrospective analysis of 490 consecutive lumbar fusion procedures performed at a single institution by 3 spine surgeons was performed. Inclusion criteria included instrumented and noninstrumented lumbar fusions performed for any etiology. Data were acquired on preoperative and postoperative hematocrit, platelets, and international normalized ratio as well as age, sex, number of levels undergoing operation, indication for surgery, and intraoperative blood loss. Multivariate logistic regression was performed to determine correlation to postoperative transfusion requirement. RESULTS: A total of 490 patients undergoing lumbar fusion were identified. Twenty-five patients (5.1%) required postoperative transfusion. No patients required readmission for anemia or transfusion. Multivariate logistic regression analysis demonstrated that reduced preoperative hematocrit and increased intraoperative blood loss were independent predictors of postoperative transfusion requirement. Intraoperative blood loss >1000 mL had an odds ratio of 8.9 (P=0.013), and preoperative hematocrit <35 had an odds ratio of 4.37 (P=0.008) of requiring a postoperative transfusion. CONCLUSIONS: Routine postoperative hematologic studies are not necessary in many patients. High intraoperative blood loss and low preoperative hematocrit were independent predictors of postoperative blood transfusion. Our results describe quantitative preoperative and intraoperative criteria to guide data-driven utilization of postoperative hematologic studies following lumbar fusion.

Comparison of operating field sterility in open versus minimally invasive microdiscectomies of the lumbar spine.

BACKGROUND: Postoperative wound infection is a preventable risk that can lead to significant adverse outcomes and increased cost of care. Minimally invasive surgeries (MIS) have been found to have lower rates of postoperative infection compared with the traditional approach. To assess if the reported difference is related to intraoperative contamination or to other factors, we assessed the surgical field for sterility. METHODS: We compared 10 MIS versus 10 traditional microdiscectomies. Swabs of the operating field were obtained before and after the procedure from multiple sites in the operating room. Positive and negative controls were taken of the skin immediately before and after preparation of the incision site. All swabs were plated out on Columbia blood agar plates and grown for 48 hours. Colony counting was performed to determine growth. RESULTS: There was no statistically significant difference in the colony counts of swab sites in traditional microdiscectomies compared with MIS microdiscectomies. There was no significant contamination of the operating field using either approach. CONCLUSIONS: In this prospective study, we found that there was no significant difference in bacterial counts in swabs of operative sites in either traditional or MIS microdiscectomies, suggesting that the decreased rate of postoperative infection in the reported literature for MIS cases may be related to other factors, such as patient selection and/or postoperative care.

Integration of physics and biology: synergistic undergraduate education for the 21st century.

This is an exciting time to be a biologist. The advances in our field and the many opportunities to expand our horizons through interaction with other disciplines are intellectually stimulating. This is as true for people tasked with helping the field move forward through support of research and education projects that serve the nation's needs as for those carrying out that research and educating the next generation of biologists. So, it is a pleasure to contribute to this edition of CBE-Life Sciences Education. This column will cover three aspects of the interactions of physics and biology as seen from the viewpoint of four members of the Division of Undergraduate Education of the National Science Foundation. The first section places the material to follow in context. The second reviews some of the many interdisciplinary physics-biology projects we support. The third highlights mechanisms available for supporting new physics-biology undergraduate education projects based on ideas that arise, focusing on those needing and warranting outside support to come to fruition.

Intraspinal primitive neuroectodermal tumor in a man with neurofibromatosis type 1: Case report and review of the literature.

BACKGROUND: The occurrence of primitive neuroectodermal tumors (PNET) in patients with neurofibromatosis type 1 (NF1) has only been reported in two other cases in English-Language literature. Owing to the rarity of intraspinal PNET and the extremely high gene mutation variability in NF1, there is currently no conclusive evidence to suggest that PNET is associated with NF1. Here, we report a case of intradural PNET in a patient with NF1. CASE DESCRIPTION: A 27-year-old male underwent a C1-C3 laminectomy for resection of an intramedullary mass. Histopathology and immunohistopathology analysis was performed. Microscopic examination and immunohistochemical staining indicated the mass was a primitive neuroectodermal tumor. Within 1 month after tumor resection, the patient developed leptomeningeal carcinomatosis. The patient was not a candidate for radiation therapy but underwent palliative systemic chemotherapy. He subsequently developed neutropenia and died 3 months after tumor resection. CONCLUSION: To our knowledge, this is the first reported intraspinal PNET associated with NF1. Genetic analysis of CNS PNETs suggests a possible correlation, but larger case series are needed to support this theory.

Esophageal injury associated with anterior cervical spine surgery.

BACKGROUND: Anterior cervical spinal surgery has been used to treat a variety of conditions including spondylosis, fracture, tumor, infection, trauma, and instability. Esophageal perforation, a rare and unusual complication of anterior cervical procedures, has been largely relegated to only incidental case reports with few large retrospective studies performed to determine true incidence, treatment, etiology, and outcome. METHODS: More than 3000 anterior cervical spine surgeries conducted over a 30-year period by 5 active practicing surgeons were reviewed. There were 3 cases of esophageal injury identified with subsequent critical evaluation to determine presentation, diagnosis, risk factors, management, and outcomes. In addition, incidence rates were calculated based on overall occurrence and antecedent risk factors. RESULTS: Two of the patients with esophageal injury had predisposing risk factors, including diverticula or cervical spine trauma. The third patient had no antecedent risk factors. Symptoms included axial spine pain, odynophagia, dysphagia, purulent spondylitis, and sepsis. Treatment consisted of one or more of the following: reoperation with exploration and repair, esophageal diversion, esophageal rest, antibiotic administration, and wound drainage. Functional outcomes were achieved in all cases with no deaths. CONCLUSIONS: Esophageal injury incidence based on overall occurrence in this study was 0.1%. Patients with no antecedent risk factors had an incidence of 0.03%. Our results compare favorably with those of the Cervical Spine Research Society survey from 1989, which predicted an incidence of 0.25% based on questionnaires filed by surgeons, representing 1 of only 2 reports that included more than 1000 patients.

Sciatica of nondisc origin and piriformis syndrome: diagnosis by magnetic resonance neurography and interventional magnetic resonance imaging with outcome study of resulting treatment.

OBJECT: Because lumbar magnetic resonance (MR) imaging fails to identify a treatable cause of chronic sciatica in nearly 1 million patients annually, the authors conducted MR neurography and interventional MR imaging in 239 consecutive patients with sciatica in whom standard diagnosis and treatment failed to effect improvement. METHODS: After performing MR neurography and interventional MR imaging, the final rediagnoses included the following: piriformis syndrome (67.8%), distal foraminal nerve root entrapment (6%), ischial tunnel syndrome (4.7%), discogenic pain with referred leg pain (3.4%), pudendal nerve entrapment with referred pain (3%), distal sciatic entrapment (2.1%), sciatic tumor (1.7%), lumbosacral plexus entrapment (1.3%), unappreciated lateral disc herniation (1.3%), nerve root injury due to spinal surgery (1.3%), inadequate spinal nerve root decompression (0.8%), lumbar stenosis (0.8%), sacroiliac joint inflammation (0.8%), lumbosacral plexus tumor (0.4%), sacral fracture (0.4%), and no diagnosis (4.2%). Open MR-guided Marcaine injection into the piriformis muscle produced the following results: no response (15.7%), relief of greater than 8 months (14.9%), relief lasting 2 to 4 months with continuing relief after second injection (7.5%), relief for 2 to 4 months with subsequent recurrence (36.6%), and relief for 1 to 14 days with full recurrence (25.4%). Piriformis surgery (62 operations; 3-cm incision, transgluteal approach, 55% outpatient; 40% with local or epidural anesthesia) resulted in excellent outcome in 58.5%, good outcome in 22.6%, limited benefit in 13.2%, no benefit in 3.8%, and worsened symptoms in 1.9%. CONCLUSIONS: This Class A quality evaluation of MR neurography's diagnostic efficacy revealed that piriformis muscle asymmetry and sciatic nerve hyperintensity at the sciatic notch exhibited a 93% specificity and 64% sensitivity in distinguishing patients with piriformis syndrome from those without who had similar symptoms (p < 0.01). Evaluation of the nerve beyond the proximal foramen provided eight additional diagnostic categories affecting 96% of these patients. More than 80% of the population good or excellent functional outcome was achieved.

A randomized, double-blinded, placebo-controlled trial of phenytoin for the prevention of early posttraumatic seizures in children with moderate to severe blunt head injury.

STUDY OBJECTIVE: We determine the efficacy of prophylactic phenytoin in preventing early posttraumatic seizures in children with moderate to severe blunt head injury. METHODS: Children younger than 16 years and experiencing moderate to severe blunt head injury were randomized to receive phenytoin or placebo within 60 minutes of presentation at 3 pediatric trauma centers. The primary endpoint was posttraumatic seizures within 48 hours; secondary endpoints were survival and neurologic outcome 30 days after injury. A Bayesian decision-theoretic clinical trial design was used to determine the probability of remaining posttraumatic seizure free for each treatment group. RESULTS: One hundred two patients were enrolled, with a median age of 6.1 years. Sixty-eight percent were boys. The 2 treatment groups were well matched. During the 48-hour observation period, 3 (7%) of 46 patients given phenytoin and 3 (5%) of 56 patients given placebo experienced a posttraumatic seizure. There were no significant differences between the treatment groups in survival or neurologic outcome after 30 days. According to these results, the probability that phenytoin has the originally hypothesized effect of reducing the rate of early posttraumatic seizures by 12.5% is 0.0053. The probability that phenytoin has any prophylactic efficacy is 0.383. The median effect size in this trial was -0.015 (seizure rate increased by 1.5% in the phenytoin group), 95% probability interval -0.127 to 0.091 (12.7% higher rate of posttraumatic seizures to a 9.1% lower rate of posttraumatic seizures with phenytoin). CONCLUSION: The rate of early posttraumatic seizures in children may be much lower than previously reported. Phenytoin did not substantially reduce that rate.

Forestier disease associated with a retroodontoid mass causing cervicomedullary compression.

OBJECT: Forestier Disease (FD) is a progressive skeletal disorder affecting predominantly older men. It is also known as diffuse idiopathic skeletal hyperostosis (DISH) and is characterized by massive anterior longitudinal ligament calcification that forms a bridge on the anterior border of the thoracic and subaxial cervical spine. To the authors' knowledge, retroodontoid masses associated with FD have not been described. METHODS: Five patients with FD and multilevel subaxial cervical fusion were treated for retroodontoid masses and cervicomedullary junction (CMJ) compression. There were four men and one woman (mean age 73 years, range 54-86 years). All patients suffered progressive neurological symptoms resulting from anterior compression of the CMJ. Four patients underwent combined transoral resection of the ligamentous mass followed by an occipitocervical fusion procedure. One patient with circumferential CMJ compression underwent a posterior decompression and occipitocervical fusion. Histopathological examination of the mass showed hypertrophic degenerative fibrocartilage. Early postoperative neurological improvement was noted in all patients. The follow-up period ranged from 4 to 19 months. At the end of the follow-up period, four patients experienced neurological improvement. One patient died 3 weeks postsurgery of pulmonary complications. CONCLUSIONS: The osseous elements of the occipitoatlantoaxial complex are not directly affected by FD. The ligamentous structures of the odontoid process, however, are exposed to significantly altered biomechanics resulting from fusion of the subaxial cervical spine associated with FD. Stress-induced compensatory ligamentous hypertrophic changes at the craniovertebral junction cause CMJ compression and subsequent neurological deterioration. This previously undescribed entity should be considered in patients with FD or DISH who present with progressive quadriparesis. Transoral decompression and posterior fusion are often needed in patients with large masses and severe progressive neurological deficits. Selected patients with smaller masses and milder neurological symptoms may be treated with posterior fusion alone.

Progressive hemorrhage after head trauma: predictors and consequences of the evolving injury.

OBJECT: Progressive intracranial hemorrhage after head injury is often observed on serial computerized tomography (CT) scans but its significance is uncertain. In this study, patients in whom two CT scans were obtained within 24 hours of injury were analyzed to determine the incidence, risk factors, and clinical significance of progressive hemorrhagic injury (PHI). METHODS: The diagnosis of PHI was determined by comparing the first and second CT scans and was categorized as epidural hematoma (EDH), subdural hematoma (SDH), intraparenchymal contusion or hematoma (IPCH), or subarachnoid hemorrhage (SAH). Potential risk factors, the daily mean intracranial pressure (ICP), and cerebral perfusion pressure were analyzed. In a cohort of 142 patients (mean age 34 +/- 14 years; median Glasgow Coma Scale score of 8, range 3-15; male/female ratio 4.3: 1), the mean time from injury to first CT scan was 2 +/- 1.6 hours and between first and second CT scans was 6.9 +/- 3.6 hours. A PHI was found in 42.3% of patients overall and in 48.6% of patients who underwent scanning within 2 hours of injury. Of the 60 patients with PHI, 87% underwent their first CT scan within 2 hours of injury and in only one with PHI was the first CT scan obtained more than 6 hours postinjury. The likelihood of PHI for a given lesion was 51% for IPCH, 22% for EDH, 17% for SAH, and 11% for SDH. Of the 46 patients who underwent craniotomy for hematoma evacuation, 24% did so after the second CT scan because of findings of PHI. Logistic regression was used to identify male sex (p = 0.01), older age (p = 0.01), time from injury to first CT scan (p = 0.02), and initial partial thromboplastin time (PTT) (p = 0.02) as the best predictors of PHI. The percentage of patients with mean daily ICP greater than 20 mm Hg was higher in those with PHI compared with those without PHI. The 6-month postinjury outcome was similar in the two patient groups. CONCLUSIONS: Early progressive hemorrhage occurs in almost 50% of head-injured patients who undergo CT scanning within 2 hours of injury, it occurs most frequently in cerebral contusions, and it is associated with ICP elevations. Male sex, older age, time from injury to first CT scan, and PTT appear to be key determinants of PHI. Early repeated CT scanning is indicated in patients with nonsurgically treated hemorrhage revealed on the first CT scan.

Imaging features and surgery-related outcomes in intraventricular neurocysticercosis.

OBJECT: Neurocysticercosis (NCC) is the most common parasitic infection of the central nervous system, and its prevalence is continuing to increase in the United States. The diagnosis of intraventricular NCC (IVNCC) may be difficult, and surgery frequently fails to resolve symptoms. A retrospective review of magnetic resonance (MR) imaging characteristics and surgery-related outcomes may improve management strategies of this disease. METHODS: The authors report the presentations, neuroimaging characteristics, surgical management, and outcomes of 30 patients with IVNCC treated over a 10-year period (mean follow-up period 4 years). Cysts were located in the lateral ventricles (five cases), the third ventricle (five cases), and the fourth ventricle (21 cases). One patient had lesions in both the lateral and fourth ventricles. Presenting symptoms were related to hydrocephalus or mass effect from the lesions. All patients underwent computerized tomography (CT) and MR imaging of the brain. Treatment consisted of shunt implantation or primary excision of an IVNCC lesion. Outcomes after operations and reoperations were evaluated in light of enhancement characteristics on MR imaging. Computerized tomography scanning demonstrated IVNCC lesions in 10% of cases, and MR revealed lesions in 100% of cases. In patients in whom gadolinium (Gd) enhancement of IVNCC lesions was demonstrated on MR imaging, the surgery-related failure rate was higher and patients required reoperation, and in those in whom gadolinium enhancement was absent the surgery-related failure rate was lower (64 and 19%, respectively; p < 0.0002). CONCLUSIONS: Magnetic resonance imaging is superior to CT scanning for detecting IVNCC lesions. The absence of pericystic Gd enhancement on MR imaging is an indication for excision of the lesions. If pericystic enhancement is present, shunt surgery should be performed, and craniotomy reserved for treatment of those patients with symptomatic lesions secondary to mass effect. A treatment algorithm based on patient symptoms, cyst location, and MR imaging Gd enhancement characteristics is proposed.

Spinal neurocysticercosis.

Worldwide, cysticercosis is the most common parasitic infection of the central nervous system. In endemic regions, the incidence of neurocysticercosis (NCC) approaches 4% of the general population. The disease is predominantly intracranial, the authors of most series generally report the incidence of spinal NCC as only 1.5 to 3% of all cases. Although spinal NCC is relatively rare, it represents a distinct clinical entity that can have devastating consequences for the patient. Because of the limited size of the spinal canal, the mass effect of these lesions is poorly tolerated. Most spinal NCC occurs in the subarachnoid space where mass effect can cause spinal cord compression, although obstruction of cerebrospinal fluid pathways due to scarring of the subarachnoid space can also cause symptoms. The authors treated six patients with spinal NCC. In five cases the lesions were located in the subarachnoid space, and in one the lesion was intramedullary. All patients with subarachnoid spinal NCC required excision of the symptomatic lesions; in two cases initial medical therapy had failed. The patient with intramedullary spinal NCC experienced mild symptoms and underwent steroid therapy. All patients experienced variably improved outcomes and were eventually ambulatory. Medical therapy should be carefully considered in selected patients in whom symptoms are stable and nonprogressive. Surgical intervention is required when severe or progressive deficits occur to prevent permanent injury. In some patients recovery may be limited as a result of inflammatory injury to the spinal cord or arachnoidal adhesions.