Intracranial Pressure Monitoring in Acute Liver Failure: Institutional Case Series.

Acute liver failure (ALF) has been associated with cerebral edema and elevated intracranial pressure (ICP), which may be managed utilizing an ICP monitor. The most feared complication of placement is catastrophic intracranial hemorrhage in the setting of severe coagulopathy. Previous studies reported hemorrhage rates between 3.8-22 % among various devices, with epidural catheters having lower hemorrhage rates and precision relative to subdural bolts and intraparenchymal catheters. We sought to identify institutional hemorrhagic rates of ICP monitoring in ALF and its associated factors in a modern series guided by protocol implantation. Patient records treated for ALF with ICP monitoring at Mayo Clinic in Rochester, MN from 1995 to 2014 were reviewed. Protocalized since 1995, epidural (EP) ICP monitors were first used followed by intraparenchymal (IP) for stage III-IV hepatic encephalopathy. The following variables and outcomes were collected: patient demographics, ICPs and treatment methods, laboratory data, imaging studies, number of days for ICP monitoring, radiographic and symptomatic hemorrhage rates, orthotopic liver transplantation rates, and death. A total of 20 ICP monitors were placed for ALF, 7 EP, and 13 IP. International normalized ratio (INR) at placement of an EP monitor was 2.4 (1.7-3.2) with maximum of 2.7 (2.0-3.6) over the following 2.3 (1-3) days. Mean EP ICP at placement was 36.3 (11-55) and maximum of 43.1 (20-70) mm Hg. INR at placement of an IP monitor was 1.3 (<0.8-3.0) with maximum value of 2.9 (1.6-5.4) over the following 4.2 (2-6) days. Mean IP ICP at placement was 9.9 (2-19) and maximum was 39.8 (11-100) mm Hg. There was one asymptomatic hemorrhage in the EP group (14.3 % hemorrhage rate) and two hemorrhages in the IP group (hemorrhage rate was 15.4 %), both of which were fatal. Overall mortality rate in the EP group was 71.4 % (5/7) with two patients receiving transplantation, and one death in the transplant group. Overall mortality in the IP group was 38.5 % (5/13) with nine liver transplantations; three of the transplanted patients died, including one of the fatal hemorrhages due to monitor placement. Intracranial hypertension is common in patients with ALF with severe hepatic encephalopathy. Monitored patients in both groups experienced elevations of ICP in the setting of intermittent coagulopathy. Severity of coagulopathy did not influence hemorrhage rate. Yet, hemorrhages related to IP monitoring can be catastrophic and may add to the overall mortality.

Outcomes following myxopapillary ependymoma resection: the importance of capsule integrity.

OBJECT While extent of resection has been shown to correlate with outcomes after myxopapillary ependymoma (MPE) resection, the effect of capsular violation has not been well studied. The role of adjuvant radiation also remains controversial. In this paper the authors' goals were to evaluate outcomes following resection of MPE based on intraoperative capsular violation and to explore the role of adjuvant radiotherapy in cases of capsular violation. METHODS A retrospective review of patients undergoing resection of MPE at 2 academic institutions between 1990 and 2013 was performed. Cases with dissemination at presentation, less than 12 months of follow-up, or incomplete records were excluded. Extent of resection was defined as en bloc if all visible tumor was removed without capsular violation, gross-total resection (GTR) if all visible tumor was removed, but with capsular violation, and subtotal resection (STR) if a known residual was left at the time of surgery. Postoperative MR images were reviewed to confirm the extent of resection. Primary outcomes were progression-free survival (PFS) and overall recurrence rates. The effects of extent of resection, capsular violation, and adjuvant radiotherapy on recurrence rates and PFS were analyzed using Kaplan-Meier statistics. Associations between recurrence and preoperative variables were evaluated using Fisher exact methods and t-tests where appropriate. RESULTS Of the 107 patients reviewed, 58 patients (53% were male) met inclusion criteria. The mean age at surgery was 40.8 years (range 7-68 years). The median follow-up was 51.5 months (range 12-243 months). Extent of resection was defined as en bloc in 46.5% (n = 27), GTR in 34.5% (n = 20), and STR in 18.9% (n = 11). No recurrences were noted in the en bloc group, compared with 15% (n = 3) and 45% (n = 5) in the GTR and STR groups. En bloc resection was achieved most frequently in tumors involving the conus. Twelve patients (20%) underwent adjuvant radiotherapy following either STR or GTR. The overall recurrence rate was 13.8% (n = 8), and the 5-year PFS was 81%. Capsular violation was associated with a higher recurrence rate (p = 0.005). Adjuvant radiotherapy showed a nonsignificant trend of lower recurrence rates (16.7% vs 31.6%, p = 0.43) and longer PFS at 5 years (83.3% vs 49.9%, p = 0.16) in cases of capsular violation. CONCLUSIONS A strong correlation between capsular violation and recurrence was found following removal of MPE and should be assessed when defining extent of resection in future studies. Although the use of adjuvant radiotherapy in cases of capsular violation showed a trend toward improved PFS, further investigation is needed to establish its role as salvage therapy also appears to be effective at halting disease progression.

Transnasal odontoid resection: is there an anatomic explanation for differing swallowing outcomes?

OBJECT: Swallowing dysfunction is common following transoral (TO) odontoidectomy. Preliminary experience with newer endoscopic transnasal (TN) approaches suggests that dysphagia may be reduced with this alternative. However, the reasons for this are unclear. The authors hypothesized that the TN approach results in less disruption of the pharyngeal plexus and anatomical structures associated with swallowing. The authors investigate the histological and gross surgical anatomical relationship between pharyngeal plexus innervation of the upper aerodigestive tract and the surgical approaches used (TN and TO). They also review the TN literature to evaluate swallowing outcomes following this approach. METHODS: Seven cadaveric specimens were used for histological (n = 3) and gross anatomical (n = 4) examination of the pharyngeal plexus with the TO and TN surgical approaches. Particular attention was given to identifying the location of cranial nerves (CNs) IX and X and the sympathetic chain and their contributions to the pharyngeal plexus. S100 staining was performed to assess for the presence of neural tissue in proximity to the midline, and fiber density counts were performed within 1 cm of midline. The relationship between the pharyngeal plexus, clivus, and upper cervical spine (C1-3) was defined. RESULTS: Histological analysis revealed the presence of pharyngeal plexus fibers in the midline and a significant reduction in paramedian fiber density from C-2 to the lower clivus (p < 0.001). None of these paramedian fibers, however, could be visualized with gross inspection or layer-by-layer dissection. Laterally based primary pharyngeal plexus nerves were identified by tracing their origins from CNs IX and X and the sympathetic chain at the skull base and following them to the pharyngeal musculature. In addition, the authors found 15 studies presenting 52 patients undergoing TN odontoidectomy. Of these patients, only 48 had been swallowing preoperatively. When looking only at this population, 83% (40 of 48) were swallowing by Day 3 and 92% (44 of 48) were swallowing by Day 7. CONCLUSIONS: Despite the midline approach, both TO and TN approaches may injure a portion of the pharyngeal plexus. By limiting the TN incision to above the palatal plane, the surgeon avoids the high-density neural plexus found in the oropharyngeal wall and limits injury to oropharyngeal musculature involved in swallowing. This may explain the decreased incidence of postoperative dysphagia seen in TN approaches. However, further clinical investigation is warranted.

Moyamoya disease in a primarily white, midwestern US population: increased prevalence of autoimmune disease.

BACKGROUND AND PURPOSE: Moyamoya disease is an uncommon, cerebrovascular occlusive disease of unknown pathogenesis. Previously described Moyamoya cohorts include predominantly Asian populations or ethnically diverse North American cohorts. To gain further insight into the pathogenesis of moyamoya, we examined clinical characteristics of a primarily white, Midwestern US population METHODS: Retrospective analysis of patients with angiographically confirmed moyamoya disease evaluated at our institution was performed. Prevalence of comorbidities, cerebrovascular risk factors, and autoimmune diseases were compared with the general population. RESULTS: Ninety-four patients with moyamoya were evaluated; 72.3% were female. Ethnic composition was primarily white (85%). A significantly higher prevalence of autoimmune disease was seen, particularly type 1 diabetes mellitus (8.5% versus 0.4% in the general population) and thyroid disease (17.0% versus 8.0% in the institutional general patient population). Hyperlipidemia was also increased (27.7% versus 16.3% in the general population). CONCLUSIONS: This study of a unique, primarily white, Midwestern population of moyamoya patients demonstrates a significantly higher prevalence of autoimmune disease than in the general population. This supports a possible autoimmune component to the pathogenesis of moyamoya disease.

Ultra-early aneurysmal rebleeding and brainstem destruction.

BACKGROUND: Early secondary neurologic deterioration after aneurysmal subarachnoid hemorrhage (SAH) may have many causes including rebleeding, hydrocephalus, parenchymal hematoma, or seizures. METHODS: Case report. RESULTS: A 69-year-old woman presented with thunderclap headache and nausea. A head computed tomography (CT) showed SAH. On initial evaluation she was awake, alert, and confused without focal neurologic deficits. Two episodes of marked clinical deterioration occurred, manifesting as acute unresponsiveness and fixed anisocoria. Serial head CTs showed massive extension of hemorrhage into the brainstem parenchyma and ventricles. CONCLUSIONS: Sudden clinical deterioration after SAH with coma and a fixed "blown" pupil may result from hemorrhage extension into the brainstem parenchyma rather than oculomotor nerve injury from compression or stretch.

Successful non-operative management for atlanto-occipital dislocation resulting in spinal cord contusion in a patient with atlanto-occipital assimilation and severe Chiari I malformation.

BACKGROUND: Atlanto-occipital dislocation (AOD) is a rare, highly morbid, and highly lethal injury that results from high-energy trauma and almost universally requires operative management for satisfactory outcomes. It can be difficult to identify the severity of injury at the time of presentation, and when diagnosis is delayed outcomes worsen significantly. Anatomic anomalies of the craniovertebral junction may further complicate its detection. When such anomalies are present either singly or in combination, they are known to cause space constraints which may increase the likelihood of spinal cord injury. Given that such anomalies and AOD are rare, few examples of patients with both are reported in the literature. Furthermore, it is not clear in what way patient management may be impacted in this context. CASE DESCRIPTION: We will present a unique case of an 18-year-old patient with traumatic AOD and an intact neurologic examination who was found to have atlanto-occipital assimilation (AOA), platybasia, basilar invagination, and severe Chiari I malformation, who was treated effectively with non-operative management. CONCLUSION: Our case demonstrates the successful application of a non-operative treatment strategy in a carefully selected patient with AOD in the context of AOA.

Incorporating Quality Improvement into Resident Education: Structured Curriculum, Evaluation, and Quality Improvement Projects.

BACKGROUND: Quality Improvement (QI) is essential for improving health care delivery and is now a required component of neurosurgery residency. However, neither a formal curriculum nor implementation strategies have been established by the Accreditation Council for Graduate Medical Education. METHODS: We describe our experience with implementing a formal QI curriculum, including structured didactics and resident led group-based QI projects. Course materials and didactics were provided by the Mayo Quality Academy. Participants were required to take a 30-question multiple-choice exam to demonstrate basic proficiency in QI methods following completion of didactic. An anonymous survey also was performed to elicit feedback from course participants. RESULTS: All of the 40 student participants (17 residents) were able to demonstrate basic proficiency in QI methods on a standardized exam upon course completion. Of the 9 attempted QI projects, 7 were completed, with 5 of those resulting in sustained process changes. The majority of participants felt formal training improved confidence in QI processes and was a valuable professional tool for their careers. CONCLUSIONS: A formal didactic curriculum and practical application of QI methodologies adds value to resident training. Further, it has the potential to positively impact practice. Consideration should be given to adopting a formal QI curriculum by other neurosurgery departments and perhaps standardization on national level.

Fusion, Failure, Fatality: Long-term Outcomes After Surgical Versus Nonoperative Management of Type II Odontoid Fracture in Octogenarians.

BACKGROUND: Type II odontoid fracture is a highly morbid injury among octogenarians, with 41% 1-year mortality. Our objective was to assess long-term fusion, complication, and survival rates. METHODS: Retrospective review of prospective trauma registry and blinded review of follow-up radiographs. RESULTS: Follow-up cohort included 94 nonoperative and 17 operative patients (median, 52 and 79 months). The operative group had significantly higher rates of repeated surgery for primary treatment failure or complication (1% vs. 18%; P = 0.01) and dysphagia, aspiration events, or tracheostomy (29% vs. 78%, P = 0.002; 6% vs. 30%, P = 0.04; 1% vs. 18%, P = 0.01). Three-year all-cause mortalities were 71% and 76%, respectively (P = 0.78). No delayed myelopathy was observed. One-year postinjury radiographs were available for 13 and 6 patients in the nonoperative and operative groups (P = 0.9); bony union was observed in 3 and 5 patients (23% vs. 83%; P = 0.04). Retrolisthesis greater than 2 mm was observed in 2 and 1 patients (15% vs. 17%; P = 1.0). Two patients in the operative group underwent repeated surgery for primary treatment failure. Dysphagia was diagnosed in 3 and 5 operative patients (23% vs. 83%; P = 0.04), whereas aspiration events occurred in 0 and 3 patients (0% vs. 50%; P = 0.02). Three-year mortalities in this cohort were 38% and 67% (P = 0.35). CONCLUSIONS: Radiographic union is significantly associated with operative management, but the corresponding clinical benefit is unclear. Complications were significantly more common after surgery. Long-term survival in octogenarians following type II odontoid fracture is poor, independent of management. Frequent complications without a proven survival benefit suggest that most patients are better managed conservatively.

The effect of diabetes mellitus on 30-day outcomes following single-level open lumbar microdiscectomy: an aged-matched case-control study.

BACKGROUND: Diabetes mellitus (DM) is a known risk factor for post-surgical complications. However, few reports specifically study lumbar spine surgical outcomes in diabetics. The purpose of this study was to assess 30-day outcomes in patients with DM undergoing single-level open lumbar microdiscectomy (oLMD). METHODS: A retrospective case control study on patients with DM undergoing between 2001 and 2012. Patients who underwent a minimally invasive approach, repeat discectomy, or multilevel surgery were excluded. One hundred and twenty-six patients were age-matched with 126 non-diabetic controls. Outcomes assessed included length of stay (LOS), postoperative urinary retention (UR), total morbidity, infection, postoperative radiculitis, 30-day re-admissions and emergency department visits, and pain status at discharge and at 30 days. Categorical variables were evaluated with Pearson's χ2 tests. Student's t-tests were used to evaluate continuous variables. Univariate logistic regression was used to evaluate strength of association of DM with outcome variables. RESULTS: Mean LOS was significantly higher in diabetic patients (1.9 vs. 1.4 days, P<0.0001). DM was associated with increased morbidity (P=0.009, OR=3.3, CI: 1.3-9.5) and UR (P<0.0001, OR=8.2, CI: 3.4-24.8). No differences were found in 30-day readmission rates or emergency department visits, pain status at discharge and at 30 days, or postoperative radiculitis. CONCLUSIONS: Overall, short-term outcomes are worse in patients with DM. Following single-level oLMD, DM is associated with longer hospital stays, UR, and increased morbidity. These short term outcomes consequently lead to an overall increase in hospital costs.

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.

Contemporary analysis of the intraoperative and perioperative complications of neurosurgical procedures performed in the sitting position.

OBJECTIVE Historically, performing neurosurgery with the patient in the sitting position offered advantages such as improved visualization and gravity-assisted retraction. However, this position fell out of favor at many centers due to the perceived risk of venous air embolism (VAE) and other position-related complications. Some neurosurgical centers continue to perform sitting-position cases in select patients, often using modern monitoring techniques that may improve procedural safety. Therefore, this paper reports the risks associated with neurosurgical procedures performed in the sitting position in a modern series. METHODS The authors reviewed the anesthesia records for instances of clinically significant VAE and other complications for all neurosurgical procedures performed in the sitting position between January 1, 2000, and October 8, 2013. In addition, a prospectively maintained morbidity and mortality log of these procedures was reviewed for instances of subdural or intracerebral hemorrhage, tension pneumocephalus, and quadriplegia. Both overall and specific complication rates were calculated in relation to the specific type of procedure. RESULTS In a series of 1792 procedures, the overall complication rate related to the sitting position was 1.45%, which included clinically significant VAE, tension pneumocephalus, and subdural hemorrhage. The rate of any detected VAE was 4.7%, but the rate of VAE requiring clinical intervention was 1.06%. The risk of clinically significant VAE was highest in patients undergoing suboccipital craniotomy/craniectomy with a rate of 2.7% and an odds ratio (OR) of 2.8 relative to deep brain stimulator cases (95% confidence interval [CI] 1.2-70, p = 0.04). Sitting cervical spine cases had a comparatively lower complication rate of 0.7% and an OR of 0.28 as compared with all cranial procedures (95% CI 0.12-0.67, p < 0.01). Sitting cervical cases were further subdivided into extradural and intradural procedures. The rate of complications in intradural cases was significantly higher (OR 7.3, 95% CI 1.4-39, p = 0.02) than for extradural cases. The risk of VAE in intradural spine procedures did not differ significantly from sitting suboccipital craniotomy/craniectomy cases (OR 0.69, 95% CI 0.09-5.4, p = 0.7). Two cases (0.1%) had to be aborted intraoperatively due to complications. There were no instances of intraoperative deaths, although there was a single death within 30 days of surgery. CONCLUSIONS In this large, modern series of cases performed in the sitting position, the complication rate was low. Suboccipital craniotomy/craniectomy was associated with the highest risk of complications. When appropriately used with modern anesthesia techniques, the sitting position provides a safe means of surgical access.

Patient-specific factors affecting hospital costs in lumbar spine surgery.

OBJECTIVE: 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.

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.

Brain Metastasis From Malignant Peripheral Nerve Sheath Tumors.

BACKGROUND: Metastatic disease is a well-known sequela of malignant peripheral nerve sheath tumors (MPNSTs). Metastic spread to the brain is unusual. CASE DESCRIPTION: A 56-year-old man was found to have a high grade MPNST of the sciatic nerve. Despite en-bloc excision of the sciatic nerve mass and local radiation postoperatively, he developed pathologically confirmed systemic metastases. He was found to have lung nodules and received chemotherapy 25 months after the diagnosis, and 32 months after the initial diagnosis, he presented with left leg weakness and sensory changes and was found to have a lesion of the frontal lobe for which he received palliative radiation. He developed systemic metastases and died 35 months after initial presentation. We retrospectively reviewed the charts of 179 patients treated at our institution with MPNSTs since 1994. This was the only case of a pathology proven brain metastasis, resulting in an incidence of 0.5%. Literature review revealed 21 cases. The mean age was found to be 37.5 years, and mean survival after development of a brain metastasis was 9.9 months. CONCLUSIONS: Brain metastases from MPNSTs are very rare and represent a poor prognosis, with survival after brain metastasis reported to be approximately 10 months. Early and effective initial diagnosis and treatment of MPNSTs likely represent the best opportunity for increased overall survival.

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.

Penetrating head injuries in children due to BB and pellet guns: a poorly recognized public health risk.

OBJECT Nonpowder guns, defined as spring- or gas-powered BB or pellet guns, can be dangerous weapons that are often marketed to children. In recent decades, advances in compressed-gas technology have led to a significant increase in the power and muzzle velocity of these weapons. The risk of intracranial injury in children due to nonpowder weapons is poorly documented. METHODS A retrospective review was conducted at 3 institutions studying children 16 years or younger who had intracranial injuries secondary to nonpowder guns. RESULTS The authors reviewed 14 cases of intracranial injury in children from 3 institutions. Eleven (79%) of the 14 children were injured by BB guns, while 3 (21%) were injured by pellet guns. In 10 (71%) children, the injury was accidental. There was 1 recognized assault, but there were no suicide attempts; in the remaining 3 patients, the intention was indeterminate. There were no mortalities among the patients in this series. Ten (71%) of the children required operative intervention, and 6 (43%) were left with permanent neurological injuries, including epilepsy, cognitive deficits, hydrocephalus, diplopia, visual field cut, and blindness. CONCLUSIONS Nonpowder guns are weapons with the ability to penetrate a child's skull and brain. Awareness should be raised among parents, children, and policy makers as to the risk posed by these weapons.

The rise and fall of the craniocervical junction relative to the hard palate: a lifetime story.

OBJECT: Endoscopic approaches to the anterior craniocervical junction are increasing in frequency. Choice of oral versus endoscopic endonasal approach to the odontoid often depends on the relationship of the C1-2 complex to the hard palate. However, it is not known how this relevant anatomy changes with age. We hypothesize that there is a dynamic relationship of C-2 and the hard palate, which changes with age, and potentially affects the choice of surgical approach. The aim of this study was to characterize the relationship of C-2 relative to the hard palate with respect to age and sex. METHODS: Emergency department billing and trauma records from 2008 to 2014 were reviewed for patients of all ages who underwent cervical or maxillofacial CT as part of a trauma evaluation for closed head injury. Patients who had a CT scan that allowed adequate visualization of the hard palate, opisthion, and upper cervical spine (C-1 and C-2) were included. Patients who had cervical or displaced facial/skull base fractures, a history of rheumatoid arthritis, or craniofacial anomalies were excluded. The distance from McGregor's palatooccipital line to the midpoint of the inferior endplate of C-2 (McL-C2) was measured on midsagittal CT scans. Patients were grouped by decile of age and by sex. A 1-way ANOVA was performed with each respective grouping. RESULTS: Ultimately, 483 patients (29% female) were included. The mean age was 46 ± 24 years. The majority of patients studied were in the 2nd through 8th decades of life (85%). Significant variation was found between McL-C2 and decile of age (p < 0.001) and sex (p < 0.001). The mean McL-C2 was 27 mm in the 1st decade of life compared with the population mean of 37 mm. The mean McL-C2 was also noted to be smaller in females (mean difference 4.8 mm, p < 0.0001). Both decile of age (p = 0.0009) and sex (p < 0.0001) were independently correlated with McL-C2 on multivariate analysis. CONCLUSIONS: The relationship of C-2 and the hard palate significantly varies with respect to age and sex, descending relative to the hard palate a full centimeter on average in adulthood. These findings may have relevance in determining optimal surgical approaches for addressing pathology involving the anterior craniocervical junction.

MRI-Guided Stereotactic System for Delivery of Intraspinal Microstimulation.

STUDY DESIGN: Laboratory/animal-based proof of principle study. OBJECTIVE: To validate the accuracy of a magnetic resonance imaging (MRI)-guided stereotactic system for intraspinal electrode targeting and demonstrate the feasibility of such a system for controlling implantation of intraspinal electrodes. SUMMARY OF BACKGROUND DATA: Intraspinal microstimulation (ISMS) is an emerging preclinical therapy, which has shown promise for the restoration of motor function following spinal cord injury. However, targeting inaccuracy associated with existing electrode implantation techniques remains a major barrier preventing clinical translation of ISMS. METHODS: System accuracy was evaluated using a test phantom comprised of nine target locations. Targeting accuracy was determined by calculating the root mean square error between MRI-generated coordinates and actual frame coordinates required to reach the target positions. System performance was further validated in an anesthetized pig model by performing MRI-guided intraspinal electrode implantation and stimulation followed by computed tomography of electrode location. Finally, system compatibility with a commercially available microelectrode array was demonstrated by implanting the array and applying a selection of stimulation amplitudes that evoked hind limb responses. RESULTS: The root mean square error between actual frame coordinates and software coordinates, both acquired using the test phantom, was 1.09 ±â€Š0.20 mm. Postoperative computed tomography in the anesthetized pig confirmed spatially accurate electrode placement relative to preoperative MRI. Additionally, MRI-guided delivery of a microwire electrode followed by ISMS evoked repeatable electromyography responses in the biceps femoris muscle. Finally, delivery of a microelectrode array produced repeatable and graded hind limb evoked movements. CONCLUSION: We present a novel frame-based stereotactic system for targeting and delivery of intraspinal instrumentation. This system utilizes MRI guidance to account for variations in anatomy between subjects, thereby improving upon existing ISMS electrode implantation techniques. LEVEL OF EVIDENCE: N/A.