Laparoscopically assisted peritoneal shunt insertion for hydrocephalus.

Over the past 50 years, various shunting procedures involving the peritoneum have been performed for the treatment of hydrocephalus. During placement of the peritoneal portion of the catheter, complications may arise secondary to a lack of direct visualization. We describe a reduced complication rate with laparoscopically-assisted placement of the peritoneal portion of the catheter. A retrospective chart review was performed of seventy-six (76) laparoscopically-assisted cases performed without consideration of prior abdominal surgery or obesity. Subjects ranged in age from 19 to 80 years. Mean operative time was 55.3 minutes. No visceral injuries occurred. To date, no infectious complications have occurred. In 3% of subjects, conversion to an open procedure was necessary after failure to establish pneumoperitoneum. Laparoscopic placement of peritoneal shunts is safe and efficacious. It provides visualization of the distal catheter target. Moreover, it reduces the risk of visceral complications, CSF pseudocysts, or extraperitoneal placement of the catheter. In the future, laparoscopic placement of the peritoneal portion of the catheter may become a standard treatment in those patients requiring placement of a peritoneal catheter.

Microvascular decompression for trigeminal neuralgia in elderly patients.

OBJECT: Although microvascular decompression (MVD) for patients with medically refractory trigeminal neuralgia (TN) is widely accepted as the treatment of choice, other "second-tier" treatments are frequently offered to elderly patients due to concerns regarding fitness for surgery. The authors sought to determine the safety and effectiveness of MVD for TN in patients older than 75 years of age. METHODS: The authors performed a retrospective review of medical records and conducted follow-up telephone interviews with the patients. The outcome data from 25 MVD operations for TN performed in 25 patients with a mean age of 79.4 years (range 75-88 years) were compared with those of a control group of 25 younger patients with a mean age of 42.3 years (range 17-50 years) who underwent MVDs during the same 30-month period from July 2000 to December 2003. RESULTS: Initial pain relief was achieved in 96% of the patients in both groups (p = 1.0). There were no operative deaths in either group. After an average follow-up period of 44 and 52 months, 78 and 72% of patients in the elderly and control groups, respectively, remained pain free without medication (p = 0.74). CONCLUSIONS: Microvascular decompression is an effective treatment for elderly patients with TN. The authors' experience suggests that the rate of complications and death after MVD for TN in elderly patients is no different from the rate in younger patients.

Hydrogel coil-related delayed hydrocephalus in patients with unruptured aneurysms.

OBJECT: Because of high recanalization rates associated with wide-necked intracranial aneurysms treated with bare platinum coils, hydrogel coils (HydroCoil, MicroVention, Inc.) have been developed. Hydrogel coils undergo progressive expansion once exposed to the physiological environment of blood and increase overall aneurysm filling. METHODS: The authors retrospectively reviewed their series of patients with unruptured aneurysms treated between 1998 and 2006 and who underwent placement of bare platinum and hydrogel coils for cerebral aneurysms. They examined the incidence of delayed hydrocephalus as related to coil type. In a subgroup of patients in which preand postprocedure CT and MR imaging studies were available, the authors quantitatively analyzed the ventricular size change after hydrogel coils were placed. RESULTS: Four of 29 patients treated with hydrogel coils developed symptomatic hydrocephalus 2-6 months after the intervention compared with 0 of 26 treated with bare platinum coils alone. The difference in ventricular size between the subgroups in which pre- and postprocedure imaging was performed was found to be statistically significant (p < 0.05). All 4 HydroCoil-treated patients in whom hydrocephalus developed required placement of a shunt. CONCLUSIONS: A 14% incidence (95% confidence interval 3.9-31.7%) of hydrocephalus in patients with unruptured aneurysm undergoing embolization with hydrogel coils was discovered. This incidence is much higher than previously reported. The mechanism by which hydrogel coils may induce hydrocephalus remains poorly understood.

Long-term survival enhanced by cordectomy in a patient with a spinal glioblastoma multiforme and paraplegia. Case report.

Spinal glioblastomas multiforme (GBMs) are rare lesions of the central nervous system with a prognosis as poor as that of their intracranial counterpart. The authors present a case of a 50-year-old man with a GBM of the spinal cord treated with surgical removal of the mass and cordectomy after the onset of paraplegia. Six years later, the patient developed hepatitis C and received interferon therapy. Six months after the start of interferon therapy, magnetic resonance imaging revealed a right cerebellar mass pathologically consistent with a GBM. Despite aggressive treatment, the patient died 1 month later. Although intracranial dissemination of spinal GBMs has been reported, this case illustrates the longest reported interval between the occurrence of a spinal GBM and its intracranial dissemination. Thus, cordectomy should be considered as a reasonable alternative in patients with complete loss of neurological function at and below the level where they harbor a malignant spinal cord astrocytoma.

Reliable Radiation Technique to Minimize Ovarian Dose During Radiation Prophylaxis of Heterotopic Ossification.

BACKGROUND/AIM: Scattered radiation during radiotherapy (RT) directed at the hip joint poses concerns about ovarian function in patients of reproductive age. Here, we report the impact of using a split-beam technique (SBT) and different photon energies on the total ovary dose during radiation prophylaxis of heterotopic ossification (HO). PATIENTS AND METHODS: This was a single-institution, retrospective study of 32-patients with traumatic acetabular fractures (TAF). All underwent surgery followed by CT-based-RT within 72 h in a single fraction of 700 cGy. Ipsilateral (IL) and contralateral (CL) ovaries (OV) were contoured separately and dose volume histograms (DVH) generated. Additional planning trials were created for each patient by utilizing a SBT medially and by using different photon energies (6-18 MV) to investigate the difference in ovary dose among these maneuvers. RESULTS: The median Mean-dose delivered to ILOV was 59 cGy and the median Max-dose was 177 cGy. CLOV median Mean-dose was 6 cGy and median Max-dose was 10 cGy. SBT at the medial edge of the field led to a 27% and 22% dose reduction in the median Mean and Max. doses, respectively, to ILOV; 9% and 5% reduction was seen in the median Mean and Max. doses, respectively, to CLOV. Higher photon energies (10-18 MV) led to an additional 28% and 16 % reduction in median Mean and Max. doses, respectively, to ILOV when compared to those from 6 MV. The CLOV median Mean dose was reduced by 18% and the Max. dose was reduced by 12%. CONCLUSION: A biologically significant radiation dose is delivered to the ovaries during HO radiation prophylaxis at the hip joints. Ipsilateral ovarian dose could be reduced by half and contralateral by one-quarter by using CT-based treatment planning with a medial SBT and photon energies above 6 MV. We suggest using no more than 10 MV to minimize neutron contamination. Those techniques should be the standard of care as it provides a reliable method for minimizing the radiation dose to the ovaries, consequently, maximizing female fertility preservation during HO radiation prophylaxis. All female patients in childbearing age should be fully informed about ovarian radiation exposure and possible temporary alteration in ova production and morphology.

Testicular Dose During Prophylaxis of Heterotopic Ossification with Radiation Therapy.

AIM: A single-institution, retrospective study was performed to investigate potential techniques to minimize radiation exposure to the testicles during heterotopic ossification (HO) prophylaxis. We report the impact of split-beam technique (SBT) and different photon energies on the total dose of radiation received by the testicles during prophylaxis of HO. MATERIALS AND METHODS: Between 2008 and 2010, we identified 64 patients with traumatic acetabular fractures who underwent surgery followed by radiation therapy (RT) without testicular shielding. Postoperative RT was delivered within 72 h in a single fraction of 700 cGy using 6-18 MV photons, without testicular shielding due to patient refusal. All patients underwent 3-D RT planning in which the testicles were contoured as a region of interest and dose-volume histograms (DVH) were generated. Additional treatment planning trials were created for each patient by utilizing a SBT medially and by using different photon energies (6, 10 and 18 MV) to study the effects of these maneuvers on the delivered dose to the testicles. RESULTS: In reviewing the DVH, it was noted that the mean dose delivered to the testicles was 10 cGy (range=3-40). The maximum dose was 31 cGy (range=7-430). When SBT was utilized, a significant reduction in the mean (44%) and maximum (47%) doses delivered to the testicles was noted. Further reductions in the mean (26%) and maximum (14%) doses were achieved by using higher-energy (10-18 MV) beams. The radiation doses to the testicles from the CT simulation and the two portal images were estimated to be 4 and 1.5 cGy, respectively. CONCLUSION: Low-dose prophylactic RT to prevent HO around the hip causes a low, but likely biologically meaningful, radiation dose to be delivered to the testicles. This dose could be further reduced by using a medial SBT and photon energies above 6 MV. Testicular shielding should be offered to all male patients receiving such RT. In addition, all patients should be informed about the consequences of testicular radiation as part of their informed consent.

Central brain herniation secondary to fulminant acute disseminated encephalomyelitis: implications for neurosurgical management. Case report.

Acute disseminated encephalomyelitis (ADEM), also known as postinfectious encephalomyelitis, is an immunologically mediated demyelinating disorder affecting the central nervous system that typically occurs after infection or vaccination. The prognosis of ADEM is generally favorable. In a small subset of patients with ADEM, however, fulminant cerebral edema requiring neurosurgical intervention will develop. Few recommendations are available to help the neurosurgeon in dealing with such cases. In this report, the authors present the case of a patient with ADEM in whom central brain herniation developed secondary to medically intractable cerebral edema. The authors review the salient features of the disease and suggest a role for neurosurgeons in cases of fulminant ADEM.

Neoadjuvant chemoradiation followed by orthotopic liver transplantation in cholangiocarcinomas: the emory experience.

BACKGROUND: Cholangiocarcinoma (CCA) is a bile duct tumor with a grim prognosis. The median survival after radiotherapy of unresectable disease is 9-12 months. The following is a review of our experience with neoadjuvant (NEO) chemoradiation followed by orthotopic liver transplantation (OLT) for CCA. METHODS: Ten patients with CCAs were selected as candidates for NEO-OLT between 2008-2011. Patients with unresectable CCA above the cystic duct without intra or extrahepatic metastases were eligible. Primary sclerosing cholangitis (PSC) patients were included due to their poor resection response. Patients initially received external-beam radiation [via conventional fields or volumetric-modulated arc therapy (VMAT)] plus capecitabine (XEL) or 5-fluorouracil (5-FU), followed by either Iridium(192) (Ir(192)) brachytherapy high dose rate (HDR) or external boost. 5-FU or XEL was administered until OLT. Patients underwent periodic surveillance computed tomography (CT)/MRIs after OLT. Primary endpoints included actuarial rates (AR)/crude rates (CR) of overall survival (OS), and local control (LC) at 6, 12, and 24 months. RESULTS: Five males and five females were identified. Mean age was 58.3 years (range, 38-71 years). Mean composite radiation dose delivered was 59.0 Gy (range, 54-71.4 Gy). Forty percent of patients had an HDR boost. Fifty percent of patients received XEL during NEO. Two patients were excluded from the analysis as they did not go on to OLT due to metastases (n=1) and death due to GI bleed (n=1). Thirty-eight percent of the OLT patients had a pathological complete response (pCR) after NEO, while 25% required a Whipple due to positive margins. Median follow-up for the OLT group was 23 months (range, 6.5-37 months). Six, twelve, and twenty-four months LC AR was 100%. LC CR was 100% at longest interval (30 months). Six, twelve, and twenty-four months OS AR was 100%, 87.5%, and 87.5%, respectively. Mean OS AR was 30.2 months (95% CI: 22.8-37.7). OS CR was 75% at longest interval (37 months). Post OLT mortality resulted from (I) unknown causes (0.5 months), (II) allograft rejection (27.25 months). Other toxicities included: necrotic myelitis 12/10 months after NEO/OLT (n=1), post NEO biliary stricture requiring new stent (n=1); post Whipple bile leak repair (n=1), and post OLT fistula (n=1), cholangitis (n=1), and wound revision (n=2). CONCLUSIONS: Our outcomes using NEO-OLT for CCA are promising and comparable to other series. These results further justify (I) use of NEO and (II) prioritization of available transplant livers for CCA management.

Dimensions of the posterior fossa in patients symptomatic for Chiari I malformation but without cerebellar tonsillar descent.

BACKGROUND: Chiari I malformation (CMI) is diagnosed by rigid radiographic criteria along with appropriate clinical symptomatology. The aim of this study was to investigate the dimensions of the posterior cranial fossa in patients without significant tonsillar descent but with symptoms comparable to CMI. METHODS: Twenty-two patients with signs and symptoms comparable to CMI but without accepted radiographic criteria of tonsillar descent > 3-5 mm were referred to our clinic for evaluation. A history and physical examination were performed on all patients. In reviewing their MRI scans, nine morphometric measurements were recorded. The measurements were compared to measurements from a cohort of twenty-five individuals with cranial neuralgias from our practice. RESULTS: For patients with Chiari-like symptomatology, the following statistically significant abnormalities were identified: reduced length of the clivus, reduced length of basisphenoid, reduced length of basiocciput, and increased angle of the tentorium. Multiple morphometric studies have demonstrated similar findings in CMI. CONCLUSION: The current classification of CMI is likely too restrictive. Preliminary morphologic data suggests that a subgroup of patients exists with tonsillar descent less than 3 mm below the foramen magnum but with congenitally hypoplastic posterior fossa causing symptomatology consistent with CMI.

Stereotactic radiosurgery of brain metastasis from melanoma.

Brain metastasis represents the most common intracranial neoplasm in adult patients. Melanoma is the third most frequent cancer histology and consequently comprises a significant portion of brain metastasis patients. Unlike the more frequent lung and breast cancers, melanoma represents a particularly challenging entity because of its radioresistant nature. Stereotactic radiosurgery appears to overcome the inherent radioresistance of brain metastasis from melanoma and, thereby, affords a high rate of local tumor control. Reports from leading centers indicate a favorable benefit to risk profile for radiosurgery in melanoma patients. Local tumor control after radiosurgery generally exceeds 80%, and neurological complications as a result of radiosurgery are infrequent. A higher performance status and lower intracranial tumor burden in melanoma patients at the time of radiosurgery are associated with longer survival. Radiosurgery may be used in conjunction upfront with radiotherapy, resection, and chemotherapy or as a salvage therapy in selected melanoma patients. Careful radiological and neurological follow-up is required to assess local tumor control and distant intracranial disease progression. Further clinical studies will be required to better define the role of upfront and salvage radiosurgery in selected cohorts of patients with brain metastasis from melanoma. However, it appears likely that radiosurgery will play an expanded role in the overall management of these patients.

Molecular determinants of proton-sensitive N-methyl-D-aspartate receptor gating.

Extracellular protons inhibit N-methyl-D-aspartate (NMDA) receptors with an IC50 value in the physiological pH range. To identify the molecular determinants of proton sensitivity, we used scanning mutagenesis of the NR1 subunit to search for residues that control proton inhibition of NMDA receptors. Homology modeling of the extracellular domains suggested that residues at which mutations perturbed pH sensitivity were localized in discrete regions. The majority of mutations that strongly affected proton sensitivity were clustered in the extracellular end of the second transmembrane domain (M3) and adjacent linker leading to the S2 portion of the glycine-binding domain of NR1. Mutations in NR2A confirmed that the analogous region controls the pH sensitivity of this subunit and also identified the linker region between the third transmembrane domain (M4) and the S2 portion of the NR2 glutamate binding domain as an additional determinant of proton sensitivity. One mutant receptor, NR1(A649C)/NR2A(A651T), showed a 145-fold reduction in the IC50 for protons (IC50, 17.3 microM corresponding to pH 4.9). The M3-S2 linker region has been suggested to control NMDA receptor gating, leading to the hypothesis that the proton sensor and receptor gate may be structurally and functionally integrated.