Optochiasmatic cavernous hemangioma.

We present a case of an optochiasmatic cavernous hemangioma (OCH) treated by stereotactic radiotherapy that required subsequent surgical resection. Subtotal resection and/or radiotherapy are not curative and can lead to hemorrhage and progressive neuronal insult. We recommend complete surgical resection as the treatment of choice.

Ras signaling influences permissiveness of malignant peripheral nerve sheath tumor cells to oncolytic herpes.

Lack of expression of neurofibromin in neurofibromatosis 1 and its lethal derivative, malignant peripheral nerve sheath tumors (MPNSTs), is thought to result in the overactivation of the Ras signaling pathway. Our previous studies have shown that cells with overactivation in the Ras pathway are more permissive to infection with herpes simplex virus 1 and its mutant version R3616. In this study, we show that among five different mouse MPNST cell lines, only the ones with elevated levels of Ras signaling are highly permissive to infection with oncolytic herpes G207. Specific inhibitors of the Ras, ERK, and JNK pathways all reduced the synthesis of viral proteins in MPNST cells. The cell lines that contained lower levels of Ras and decreased activation of downstream signaling components underwent an enhancement in apoptosis upon exposure to G207. Additionally, mouse SW10 Schwann cells were able to become infected by parental herpes but were found to be resistant to G207. The immortalization of these cell lines with the expression of SV40 large T antigen increased the levels of Ras activation and permissiveness to oncolytic herpes. A Ras/Raf kinase inhibitor reduced the synthesis of both herpes simplex virus-1 and G207 proteins in SW10 cells. The results of this study, therefore, introduce Ras signaling as a divergent turning point for the response of MPNST cells to an assault by oncolytic herpes.

Molecular imaging with targeted contrast ultrasound.

Molecular imaging with contrast-enhanced ultrasound uses targeted microbubbles that are retained in diseased tissue. The resonant properties of these microbubbles produce acoustic signals in an ultrasound field. The microbubbles are targeted to diseased tissue by using certain chemical constituents in the microbubble shell or by attaching disease-specific ligands such as antibodies to the microbubble. In this review, we discuss the applications of this technique to pathological states in the cerebrovascular system including atherosclerosis, tumor angiogenesis, ischemia, intravascular thrombus, and inflammation.

Anterior screw fixation of a dislocated type II odontoid fracture facilitated by transoral and posterior cervical manual reduction.

BACKGROUND: Early fixation of type II odontoid fractures has been shown to provide high rates of long-term stabilization and osteosynthesis. CASE: In this report, the authors present the case of a patient with a locked type II odontoid fracture treated by anterior screw fixation facilitated by closed transoral and posterior cervical manual reduction. CONCLUSION: While transoral intraoperative reduction of a partially displaced odontoid fracture has previously been described, the authors present the first case utilizing this technique in the treatment of a completely dislocated type II odontoid fracture.

Complications following pediatric cranioplasty after decompressive craniectomy: a multicenter retrospective study.

OBJECTIVE In children, the repair of skull defects arising from decompressive craniectomy presents a unique set of challenges. Single-center studies have identified different risk factors for the common complications of cranioplasty resorption and infection. The goal of the present study was to determine the risk factors for bone resorption and infection after pediatric cranioplasty. METHODS The authors conducted a multicenter retrospective case study that included all patients who underwent cranioplasty to correct a skull defect arising from a decompressive craniectomy at 13 centers between 2000 and 2011 and were less than 19 years old at the time of cranioplasty. Prior systematic review of the literature along with expert opinion guided the selection of variables to be collected. These included: indication for craniectomy; history of abusive head trauma; method of bone storage; method of bone fixation; use of drains; size of bone graft; presence of other implants, including ventriculoperitoneal (VP) shunt; presence of fluid collections; age at craniectomy; and time between craniectomy and cranioplasty. RESULTS A total of 359 patients met the inclusion criteria. The patients' mean age was 8.4 years, and 51.5% were female. Thirty-eight cases (10.5%) were complicated by infection. In multivariate analysis, presence of a cranial implant (primarily VP shunt) (OR 2.41, 95% CI 1.17-4.98), presence of gastrostomy (OR 2.44, 95% CI 1.03-5.79), and ventilator dependence (OR 8.45, 95% CI 1.10-65.08) were significant risk factors for cranioplasty infection. No other variable was associated with infection. Of the 240 patients who underwent a cranioplasty with bone graft, 21.7% showed bone resorption significant enough to warrant repeat surgical intervention. The most important predictor of cranioplasty bone resorption was age at the time of cranioplasty. For every month of increased age the risk of bone flap resorption decreased by 1% (OR 0.99, 95% CI 0.98-0.99, p < 0.001). Other risk factors for resorption in multivariate models were the use of external ventricular drains and lumbar shunts. CONCLUSIONS This is the largest study of pediatric cranioplasty outcomes performed to date. Analysis included variables found to be significant in previous retrospective reports. Presence of a cranial implant such as VP shunt is the most significant risk factor for cranioplasty infection, whereas younger age at cranioplasty is the dominant risk factor for bone resorption.

Evaluation of microporous polysaccharide hemospheres for parenchymal hemostasis during laparoscopic partial nephrectomy in the porcine model.

OBJECTIVES: We evaluated the efficacy of Microporous Polysaccharide Hemospheres (MPH) for parenchymal hemostasis during laparoscopic partial nephrectomy (LPN) in the porcine model. METHODS: Six female farm pigs underwent a transperitoneal right lower-pole LPN during occlusion of the renal hilum. Renal parenchyma was excised using cold Endoshears. MPH was applied to the defect and the hilar clamp released. Animals were kept alive for one week. Before sacrifice, left LPN was similarly performed using MPH. Study variables included blood loss, number of MPH applications, hilar clamp time, hemostasis time, perioperative complications, and abnormalities noted at sacrifice. RESULTS: Hemostasis was achieved in all kidneys solely by using MPH. The average excised specimen represented 5.6% (range, 3.6 to 8.5) of renal weight. Mean hilar clamp and hemostatic times were 12.8 minutes (range, 6 to 18) and 2 minutes (range, 1 to 3), respectively. Hemostasis occurred after one MPH application in 8 kidneys (67%). In 3 kidneys, additional MPH powder was required to treat minor residual bleeding. In the remaining kidney, a second standard MPH application was required for hemostasis. No operative complications were encountered. No hematomas or residual MPH was found at necropsy; however, small urinomas were found in 2 of 6 kidneys. CONCLUSIONS: In the experimental porcine model, this initial study suggests that MPH provides effective parenchymal hemostasis during laparoscopic resection of an exophytic kidney lesion.

Resolution of diabetes insipidus following gamma knife surgery for a solitary metastasis to the pituitary stalk. Case report.

The authors present the case of a 58-year-old woman who presented with symptoms of diabetes insipidus (DI) 1 year after she was found to have a Stage 3 (of 4) estrogen receptor-positive infiltrating ductal adenocarcinoma of the left breast with pulmonary and bone metastases. Magnetic resonance images demonstrated a solitary site of metastasis in the patient's pituitary stalk, and gamma knife surgery (GKS) was performed to treat the lesion. Three months after GKS the patient was able to reduce the medication she required for the DI. There was no evidence of pituitary failure and no negative effect on her vision.

Timing of cranioplasty after decompressive craniectomy for trauma.

BACKGROUND: The optimal timing of cranioplasty after decompressive craniectomy for trauma is unknown. The aim of this study was to determine if early cranioplasty after decompressive craniectomy for trauma reduces complications. METHODS: Consecutive cases of patients who underwent autologous cranioplasty after decompressive craniectomy for trauma at a single Level I Trauma Center were studied in a retrospective 10 year data review. Associations of categorical variables were compared using Chi-square test or Fisher's exact test. RESULTS: A total of 157 patients were divided into early (<12 weeks; 78 patients) and late (≥12 weeks; 79 patients) cranioplasty cohorts. Baseline characteristics were similar between the two cohorts. Cranioplasty operative time was significantly shorter in the early (102 minutes) than the late (125 minutes) cranioplasty cohort (P = 0.0482). Overall complication rate in both cohorts was 35%. Infection rates were lower in the early (7.7%) than the late (14%) cranioplasty cohort as was bone graft resorption (15% early, 19% late), hydrocephalus rate (7.7% early, 1.3% late), and postoperative hematoma incidence (3.9% early, 1.3% late). However, these differences were not statistically significant. Patients <18 years of age were at higher risk of bone graft resorption than patients ≥18 years of age (OR 3.32, 95% CI 1.25-8.81; P = 0.0162). CONCLUSIONS: After decompressive craniectomy for trauma, early (<12 weeks) cranioplasty does not alter the incidence of complication rates. In patients <18 years of age, early (<12 weeks) cranioplasty increases the risk of bone resorption. Delaying cranioplasty (≥12 weeks) results in longer operative times and may increase costs.

An ACGME Duty Hour Compliant 3-Person Night Float System for Neurological Surgery Residency Programs.

BACKGROUND: In 2003, the Accreditation Council for Graduate Medical Education (ACGME) instituted the 24+6-hour work schedule and 80-hour workweek, and in 2011, it enhanced work hour and supervision standards. INNOVATION: In response, Oregon Health & Science University's (OHSU) neurological surgery residency instituted a 3-person night float system. METHODS: We analyzed work hour records and operative experience for 1 year before and after night float implementation in a model that shortened a combined introductory research and basic clinical neurosciences rotation from 12 to 6 months. We analyzed residents' perception of the system using a confidential survey. The ACGME 2011 work hour standards were applied to both time periods. RESULTS: AFTER NIGHT FLOAT IMPLEMENTATION, THE NUMBER OF DUTY HOUR VIOLATIONS WAS REDUCED: 28-hour shift (11 versus 235), 8 hours off between shifts (2 versus 20), 80 hours per week (0 versus 17), and total violations (23 versus 275). Violations increased only for the less than 4 days off per 4-week interval rule (10 versus 3). No meaningful difference was seen in the number of operative cases performed per year at any postgraduate year (PGY) training level: PGY-2 (336 versus 351), PGY-3 (394 versus 354), PGY-4 (803 versus 802), PGY-5 (1075 versus 1040), PGY-7 (947 versus 913), and total (3555 versus 3460). Residents rated the new system favorably. CONCLUSIONS: To meet 2011 ACGME duty hour standards, the OHSU neurological surgery residency instituted a 3-person night float system. A nearly complete elimination of work hour violations did not affect overall resident operative experience.

Complications after surgery for lumbar stenosis in a veteran population.

STUDY DESIGN: Secondary analysis of the prospectively collected Veterans Affairs National Surgical Quality Improvement Program database. OBJECTIVE: Determine rates of major medical complications, wound complications, and mortality among patients undergoing surgery for lumbar stenosis and examine risk factors for these complications. SUMMARY OF BACKGROUND DATA: Surgery for spinal stenosis is concentrated among older adults, in whom complications are more frequent than among middle-aged patients. Many studies have focused on infections or device complications, but fewer studies have focused on major cardiopulmonary complications, using prospectively collected data. METHODS: We identified patients who underwent surgery for a primary diagnosis of lumbar stenosis between 1998 and 2009 from the Veterans Affairs National Surgical Quality Improvement Program database. We created a composite of major medical complications, including acute myocardial infarction, stroke, pulmonary embolism, pneumonia, systemic sepsis, coma, and cardiac arrest. RESULTS: Among 12,154 eligible patients, major medical complications occurred in 2.1%, wound complications in 3.2%, and 90-day mortality in 0.6%. Major medical complications, but not wound complications, were strongly associated with age. American Society of Anesthesiologists (ASA) class was a strong predictor of complications. Insulin use, long-term corticosteroid use, and preoperative functional status were also significant predictors. Fusion procedures were associated with higher complication rates than with decompression alone. In logistic regressions, ASA class and age were the strongest predictors of major medical complications (odds ratio for ASA class 4 vs. class 1 or 2: 2.97; 95% confidence interval, 1.68-5.25; P = 0.0002). After adjustment for comorbidity, age, and functional status, fusion procedures remained associated with higher medical complication rates than were decompressions alone (odds ratio = 2.85; 95% confidence interval, 2.14-3.78; P < 0.0001). CONCLUSION: ASA class, age, type of surgery, insulin or corticosteroid use, and functional status were independent risk factors for major medical complications. These factors may help in selecting patients and planning procedures, improving patient safety.

Timing of cranioplasty after decompressive craniectomy for ischemic or hemorrhagic stroke.

OBJECT: The optimal timing of cranioplasty after decompressive craniectomy for stroke is not known. Case series suggest that early cranioplasty is associated with higher rates of infection while delaying cranioplasty may be associated with higher rates of bone resorption. The authors examined whether the timing of cranioplasty after decompressive craniectomy for stroke affects postoperative complication rates. METHODS: A retrospective cohort study was undertaken to evaluate complication rates in patients undergoing cranioplasty at early (within 10 weeks of craniectomy) or late (≥ 10 weeks) stages. Multivariate logistic regression analysis was used to determine characteristics that would predict complications in patients undergoing cranioplasty after decompressive craniectomy for stroke. RESULTS: While the overall complication rate was higher in the early cranioplasty cohort (22% vs 16% in the late cranioplasty cohort), the difference was not statistically significant (p = 0.5541). Patients in the early cranioplasty cohort had lower rates of postoperative hematoma but higher rates of infection. Presence of a CSF shunt was the only significant predictor of complications (OR 8.96, 95% CI 1.84-43.6). CONCLUSIONS: Complications rates for early cranioplasty (within 10 weeks of craniectomy) are similar to those encountered when cranioplasty is delayed, although the cohort size in this study was too small to state equivalence. Patients with a ventriculoperitoneal shunt are at higher risk for complications after cranioplasty.

Optimal timing of autologous cranioplasty after decompressive craniectomy in children.

OBJECT: The object of this study was to determine if early cranioplasty after decompressive craniectomy for elevated intracranial pressure in children reduces complications. METHODS: Sixty-one consecutive cases involving pediatric patients who underwent autologous cranioplasty after decompressive craniectomy for raised intracranial pressure at a single academic children's hospital over 15 years were studied retrospectively. RESULTS: Sixty-one patients were divided into early (< 6 weeks; 28 patients) and late (≥ 6 weeks; 33 patients) cranioplasty cohorts. The cohorts were similar except for slightly lower age in the early (8.03 years) than the late (10.8 years) cranioplasty cohort (p < 0.05). Bone resorption after cranioplasty was significantly more common in the late (42%) than the early (14%) cranioplasty cohort (p < 0.05; OR 5.4). No other complication differed in incidence between the cohorts. CONCLUSIONS: After decompressive craniectomy for raised intracranial pressure in children, early (< 6 weeks) cranioplasty reduces the occurrence of reoperation for bone resorption, without altering the incidence of other complications.

Ral overactivation in malignant peripheral nerve sheath tumors.

Ras leads an important signaling pathway that is deregulated in neurofibromatosis type 1 and malignant peripheral nerve sheath tumor (MPNST). In this study, we show that overactivation of Ras and many of its downstream effectors occurred in only a fraction of MPNST cell lines. RalA, however, was overactivated in all MPNST cells and tumor samples compared to nontransformed Schwann cells. Silencing Ral or inhibiting it with a dominant-negative Ral (Ral S28N) caused a significant reduction in proliferation, invasiveness, and in vivo tumorigenicity of MPNST cells. Silencing Ral also reduced the expression of epithelial mesenchymal transition markers. Expression of the NF1-GTPase-related domain (NF1-GRD) diminished the levels of Ral activation, implicating a role for neurofibromin in regulating RalA activation. NF1-GRD treatment caused a significant decrease in proliferation, invasiveness, and cell cycle progression, but cell death increased. We propose Ral overactivation as a novel cell signaling abnormality in MPNST that leads to important biological outcomes with translational ramifications.

Primary melanocytic tumor of the cerebellopontine angle mimicking a vestibular schwannoma: case report.

OBJECTIVE: The majority of tumors of the cerebellopontine angle (CPA) are benign. We report the case of a primary malignant melanoma of the CPA that mimicked a vestibular schwannoma (acoustic neuroma). We discuss the differential diagnosis and prognosis of melanotic lesions at this location. CLINICAL PRESENTATION: A 49-year-old man presented with a 7-year history of unilateral deafness and a several month history of imbalance, intractable nausea and vomiting, as well as weight loss. A neurological work-up revealed a large tumor in the left CPA radiographically diagnosed as a vestibular schwannoma. INTERVENTION: A translabyrinthine approach revealed a pigmented, vascular neoplasm encasing vessels and cranial nerves of the left CPA. The tumor was subtotally resected, and a histopathological diagnosis of melanoma was made. The patient had no history of cutaneous melanoma and no other site of disease was ever discovered. CONCLUSION: This case most likely represents primary melanoma of the central nervous system that mimicked a vestibular schwannoma. The differential diagnosis of melanotic lesions of the CPA is discussed as are the prognostic implications of each diagnosis.

Evaluation of microporous polysaccharide hemospheres as a novel hemostatic agent in open partial nephrectomy: favorable experimental results in the porcine model.

PURPOSE: Microporous polysaccharide hemospheres (MPH, Medafor, Minneapolis, Minneapolis) are a novel hemostatic agent made from purified plant starch. MPH activates the clotting cascade and hyperconcentrates platelets and coagulation proteins, while enhancing a hemostatic plug. We evaluated the hemostatic efficacy of MPH compared with standard surgical technique in a porcine open partial nephrectomy model. MATERIALS AND METHODS: Standardized lower pole partial nephrectomy was consecutively performed in each kidney of 12 female pigs. Each pig was randomized to 2 groups, namely treatment with MPH application or control with the conventional surgical technique (oxidized cellulose with bolster sutures). The right kidney was harvested 1 half-hour after hemostasis was achieved and the left kidney was harvested after 7 days. RESULTS: Mean animal and resected renal tissue weight were comparable. Ischemic and hemostasis times were significantly decreased in the MPH treated group (2.67 and 4.67 minutes, respectively) vs the control group (8.33 and 7.75 minutes, respectively) (each p = 0.004). Blood loss was equivocal (0.88 gm in the treatment group vs 2.09 gm in the control group, p = 0.07). No hemostatic complications were noted in either group. No evidence of residual foreign material was found in the MPH group at 1 week. CONCLUSIONS: MPH provided rapid, effective and durable hemostasis in the porcine open partial nephrectomy model. Additional experimental and clinical evaluation is warranted to define the role of MPH assisted partial nephrectomy in humans.