Encephaloduroarteriosynangiosis with Dural Inversion for Moyamoya Disease in a Pediatric and Adult Population-a Single-Center 20-Year Experience.

BACKGROUND: Moyamoya disease refers to a progressive vasostenotic or vaso-occlusive disease that puts patients at risk for ischemic and/or hemorrhagic events. Surgical revascularization procedures aim to restore cerebral blood flow to mitigate stroke risk and functional decline. Direct and indirect bypass procedures have been proposed. Encephaloduroarteriosynangiosis (EDAS) with dural inversion is a well-accepted indirect procedure. METHODS: Patients with moyamoya disease undergoing EDAS with dural inversion between 2000 and 2019 were retrospectively reviewed. Clinical data including short-term and long-term outcome were measured using the modified Rankin Scale. Patient satisfaction was assessed in patients with a minimum of 3 years of clinical follow-up. RESULTS: Over a 20-year period, 54 patients underwent 88 EDAS with dural inversion procedures. Most patients underwent bilateral surgery (34/54 patients, 63.0%). Median age at surgery was 19 years (range, 1-63 years) with a median follow-up of 6 years (range, 1-20 years). Periprocedural complications occurred in 4 of 54 patients (7.4%). Periprocedural infarction occurred in 3 of 88 operations (3.4%). Functional outcome at 90 days was favorable (modified Rankin Scale score 0-2) in 92.6% of cases. On long-term follow-up, 3 patients experienced ischemic infarction (5.6%), and 1 patient (1.9%) experienced hemorrhagic infarction. Patients' overall satisfaction with the surgical procedure at last follow-up was determined in 36 of 45 patients with at least 3 years of follow-up (response rate 80.0%). Median satisfaction was very good (score 5; range, 3-5). CONCLUSIONS: EDAS with dural inversion is a safe and effective indirect revascularization procedure for pediatric and adult moyamoya disease that is associated with favorable long-term outcomes and high patient satisfaction.

Predicting and reducing cranioplasty infections by clinical, radiographic and operative parameters - A historical cohort study.

Cranioplasty is a relatively straightforward and common procedure, yet it carries a substantial rate of infection that causes major morbidity and mortality. The authors' objective was to assess the effect of various variables on the risk of developing post-cranioplasty infections, and to enable the prediction and reduction of its incidence, contributing to an improved patient-selection. The medical records, microbiologic cultures, imaging studies and operative reports of patients who have undergone cranioplasty between the years 2008-2014 at Sheba Medical Center, a tertiary care teaching hospital in Tel-Hashomer, Israel, were reviewed and evaluated for potential predictive factors of infection. Cox regression was applied for uni- as well as multi-variate analyses, and a Kaplan-Meier curve and Log-Rank test were used to describe the association between neurological deficit prior to operation and occurrence of infection. Eighty-eight patients who had undergone cranioplasties using autologous as well as various artificial materials were included in the study. The overall rate of infection was 13.6%; median time to infection was 30.5 days (interquartile range: 17.35-43.5). Pre-operative degree of neurological disability was the strongest predictor for infection in both uni- and multi-variate analyses (Hazard ratio [HR]=18.9, 95% confidence interval [CI]: 1.9-187 p=0.014). Patients admitted due to trauma (HR=7.04 CI: 0.9-54.6, p=0.062) and autologous graft material (HR=2.88, 95% CI: 0.92-9.09, p=0.07) were associated with a trend toward a higher risk for infection. In conclusion, careful patient selection is a key concept in avoiding harmful post-cranioplasty infections. Modified Rankin Score yields a well-established tool that predicts the risk of infection.

MRI features have a role in pre-surgical planning of colloid cyst removal.

BACKGROUND: Endoscopic resection is becoming a well-established treatment option for patients with colloid cysts of the third ventricle. A disadvantage of this approach is the decreased ability to resect cysts in their entirety. Correlations between magnetic resonance imaging (MRI) features and cyst content could potentially help surgeons decide on the extent of resection and approach. We attempted to identify a correlation between patients' MRI imaging patterns and difficult cyst removal, post-operative adverse outcomes and the need for cerebrospinal fluid (CSF) diversion, in order to detect markers that may affect pre-surgical planning. METHOD: A retrospective examination of all patients' records that underwent a colloid cyst excision attempt at our institution between 2001 and 2014, and which had a minimum 1-year follow-up was compiled. RESULTS: Of the 25 patients fulfilling the criteria, we found cysts with a low T2 signal, specifically when combined with high T1 signal, to be significantly correlated with piecemeal, difficult removals. Correlation was also found between high T2 signal cysts and pre-operative hydrocephalus. Among patients that had pre-existing hydrocephalus, those that required a piecemeal removal possessed a strong trend towards a need for subsequent shunting. CONCLUSIONS: We found specific MRI features suggestive of difficult cyst excision. In a subgroup of patients with pre-operative hydrocephalus and imaging features suggestive of difficult removal, significantly higher rates of shunting were observed. We therefore recommend an open approach in cases of low T2, high T1 signal cysts with a diameter of over 15 mm, or CSF shunting in poor surgical candidates. Smaller cysts, with a low T1 signal, a high T2 signal and pre-operative hydrocephalus, constitute a subgroup in which we recommend endoscopic intervention as the procedure of choice.

A medulloblastoma showing an unusually long doubling time: reflection of its singular nature.

CASE DESCRIPTION: In this paper, we present a case of a 4-year-old male diagnosed with a desmoplastic, SHH-type medulloblastoma. Retrospectively, we discovered that the patient underwent an MRI scan at 21 months for reasons unrelated, revealing a T1-enhanced lesion at the vermis, later recognized as the source of the tumor. This unique case provides us with a glimpse into the natural history of this tumor. Our ability to measure tumor volume at two defined time points, 31 months apart, enabled us to deduce the tumor's doubling time. This is defined as the time of one cell cycle divided by the amount of cycling cells, multiplied by cell loss factor. Potential doubling time (Tpot) and actual doubling time (Td), calculated using the Gompertzian model, are the most clinically relevant with regard to a tumor's response to radiotherapy. Here, we show an actual doubling-time (Td) of 78 days, and an extrapolated tumor diameter at the time of birth of 0.25 mm. CLINICAL RELEVANCE: These results both support the medulloblastoma's embryonic origin, and indicating a threefold longer actual doubling time when compared to previous studies. Taking into account the reported range of medulloblastoma potential doubling time, we deduced a cell loss factor of between 48.9 and 95.5 %. These percentages fall in line with other malignant tumors. Although limited due to the obvious reliance on only two points in time and using the Gompertzian model to complete the remainder, to the best of our knowledge, this is the longest follow-up period reported for medulloblastoma. We have described how a unique turn of events enabled us to get a glimpse into the in situ development of a medulloblastoma over a 31-month period. Regarded sometimes as an idiosyncratic tumor comprised of an array of molecular changes, the complexity of medulloblastoma is displayed here, by revealing for the first time an actual doubling time three- to fourfold the previously known length.

Delayed contrast extravasation MRI: a new paradigm in neuro-oncology.

BACKGROUND: Conventional magnetic resonance imaging (MRI) is unable to differentiate tumor/nontumor enhancing tissues. We have applied delayed-contrast MRI for calculating high resolution treatment response assessment maps (TRAMs) clearly differentiating tumor/nontumor tissues in brain tumor patients. METHODS: One hundred and fifty patients with primary/metastatic tumors were recruited and scanned by delayed-contrast MRI and perfusion MRI. Of those, 47 patients underwent resection during their participation in the study. Region of interest/threshold analysis was performed on the TRAMs and on relative cerebral blood volume maps, and correlation with histology was studied. Relative cerebral blood volume was also assessed by the study neuroradiologist. RESULTS: Histological validation confirmed that regions of contrast agent clearance in the TRAMs >1 h post contrast injection represent active tumor, while regions of contrast accumulation represent nontumor tissues with 100% sensitivity and 92% positive predictive value to active tumor. Significant correlation was found between tumor burden in the TRAMs and histology in a subgroup of lesions resected en bloc (r(2) = 0.90, P < .0001). Relative cerebral blood volume yielded sensitivity/positive predictive values of 51%/96% and there was no correlation with tumor burden. The feasibility of applying the TRAMs for differentiating progression from treatment effects, depicting tumor within hemorrhages, and detecting residual tumor postsurgery is demonstrated. CONCLUSIONS: The TRAMs present a novel model-independent approach providing efficient separation between tumor/nontumor tissues by adding a short MRI scan >1 h post contrast injection. The methodology uses robust acquisition sequences, providing high resolution and easy to interpret maps with minimal sensitivity to susceptibility artifacts. The presented results provide histological validation of the TRAMs and demonstrate their potential contribution to the management of brain tumor patients.

A new fiber-mediated carbon dioxide laser facilitates pediatric spinal cord detethering. Technical note.

OBJECT: The authors report their experience with a novel flexible fiber capable of transmitting CO(2) laser energy during spinal cord tumor resection and detethering. METHODS: A fiber optic system capable of transmitting CO(2) laser energy was used in the detethering of the spinal cord in 3 cases. The first case involved a 9-year-old girl with a terminal lipoma. The second case was an 11-month-old boy with a thoracic intramedullary dermoid and dermal sinus tract. The third case involved a 13-year-old girl suffering from a tethered spinal cord subsequent to a previously repaired myelomeningocele. RESULTS: In all 3 cases, the new fiber CO(2) laser technology allowed the surgeon to perform microsurgical dissection while sparing adjacent neurovascular structures without time-consuming setup. The system was easy to implement, more ergonomic than previous technologies, and safe. The CO(2) laser provided the ability to cut and coagulate while sparing adjacent tissue because of minimal energy dispersion and ease of use, without the articulating arms involved in the prior generation of lasers. CONCLUSIONS: Using a flexible fiber to conduct CO(2) laser energy allows accurate microneurosurgical dissection and renders this instrument a high-precision and ergonomic surgical tool in the setting of spinal cord detethering.

Surgery for convexity meningiomas.

OBJECTIVE: Meningiomas that occur over the convexity of the brain are the most common meningiomas, but little has been published about their contemporary management. We aimed to analyze a large series of convexity meningiomas with respect to surgical technique, complication rates, and pathological factors leading to recurrence. METHODS: We retrospectively reviewed 163 cases of convexity meningiomas operated on in our institution by the senior author (PMB) between 1986 and 2005. The median follow-up time was 2.3 years (range, 1-13 yr). RESULTS: Convexity tumors represented 22% of all meningiomas operated on. There was a female:male ratio of 2.7:1. Median age was 57 years (range, 20-89 yr). Image-guided surgery was used on all cases in the last 5 years. The 30-day mortality rate was 0%. The incidence of new neurological deficits was 1.7%, and the overall complication rate was 9.4%. The pathology of the tumors was benign in 144 (88.3%), atypical in 16 (9.8%), and anaplastic/malignant in 3 (1.8%). In six of the cases designated "benign," there were borderline atypical features. The 5-year recurrence rate for benign meningiomas was 1.8%, atypical meningiomas 27.2%, and anaplastic meningiomas 50%. The two cases of benign tumor recurrences involved tumors with borderline atypia and high MIB-1 indices. The borderline atypical cases had a 5-year recurrence-free survival rate of only 55.9%, more closely approximating that of tumors designated "atypical." CONCLUSION: Convexity meningiomas can be safely removed using modern image-guided minimally invasive surgical techniques with a very low operative mortality. Benign convexity meningiomas having a Simpson Grade I complete excision have a very low recurrence rate. The recurrence rates of atypical and malignant tumors are significantly higher, and borderline atypical tumors should be considered to behave more like atypical rather than benign lesions. Longer-term follow-up data are needed to more accurately determine the recurrence rates of benign meningiomas.

Surgery for extra-axial tumors of the cerebral convexity and midline.

Extra-axial tumors of the cerebral convexity and midline include both convexity and parasagittal meningiomas; they are the most common tumors of the cranial vault and are the principal topic of this article. Over the past 30 years, neurosurgery has witnessed steady change in both technological capacity and in conceptualization of certain diseases. Meningiomas are good examples of this change. Although cranial base meningiomas have received the most attention in the past two decades, the management of cranial vault meningiomas has also changed significantly. Particular issues include decisions about when to treat, deciding between surgery and radiosurgery, increasing use of image-guided surgery, the understanding of the biology of these tumors, and changing attitudes in the management of the sagittal sinus. These issues exemplify the changing biological, conceptual, and technological concepts that characterize contemporary neurosurgery.