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Andre Nzokou, Alexander G. Weil and Daniel Shedid

Object

Resection of spinal tumors traditionally requires bilateral subperiosteal muscle stripping, extensive laminectomy, and, in cases of foraminal extension, partial or radical facetectomy. Fusion is often warranted in cases of facetectomy to prevent deformity, pain, and neurological deterioration. Recent reports have demonstrated safety and efficacy of mini-open removal of these tumors using expandable tubular retractors. The authors report their experience with the minimally invasive removal of extradural foraminal and intradural-extramedullary tumors using the nonexpandable tubular retractor.

Methods

A retrospective chart review of consecutive patients who underwent minimally invasive resection of spinal tumors at Notre Dame Hospital was performed.

Results

Between December 2005 and March 2012, 13 patients underwent minimally invasive removal of spinal tumors at Notre Dame Hospital, Montreal. There were 6 men and 7 women with a mean age of 55 years (range 20–80 years). There were 2 lumbar and 2 thoracic intradural-extramedullary tumors and 7 thoracic and 2 lumbar extradural foraminal tumors. Gross-total resection was achieved in 12 patients. Subtotal resection (90%) was attained in 1 patient because the tumor capsule was adherent to the diaphragm. The average duration of surgery was 189 minutes (range 75–540 minutes), and the average blood loss was 219 ml (range 25–500 ml). There were no major procedure-related complications. Pathological analysis revealed benign schwannoma in 8 patients and meningioma, metastasis, plasmacytoma, osteoid osteoma, and hemangiopericytoma in 1 patient each. The average equivalent dose of postoperative narcotics after surgery was 66.3 mg of morphine. The average length of hospitalization was 66 hours (range 24–144 hours). All working patients returned to normal activities within 4 weeks. The average MRI and clinical follow-up were 13 and 21 months, respectively (range 2–68 months). At last follow-up, 92% of patients had improvement or resolution of pain with a visual analog scale score that improved from 7.8 to 1.2. All patients with neurological impairment improved. The American Spinal Injury Association grade improved in all but 1 patient.

Conclusions

Intradural-extramedullary and extradural tumors can be completely and safely resected through a minimally invasive approach using the nonexpandable tubular retractor. This approach may be associated with even less tissue destruction than mini-open techniques, translating into a quicker functional recovery. In cases of foraminal tumors, by eliminating the need for facetectomy, this minimally invasive approach may decrease the incidence of postoperative deformity and eliminate the need for adjunctive fusion surgery.

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Andre Nzokou, Alexander G. Weil and Daniel Shedid

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Alexander G. Weil and Sanjiv Bhatia

Ventrally-located intramedullary cervical spinal cord cavernomas are rare entities in the pediatric population. Surgical access to these lesions is challenging. The authors present the complete resection of a symptomatic ventral cervical intramedullary cavernoma through an anterior approach in a 15-year-old boy. The lesion was accessed following left anterolateral dissection, C3–4 discectomy and C3/C4 partial corpectomy. The authors will discuss the rationale for intervening in this patient and for selecting this anterior approach over other approaches, such as the anterolateral, posterolateral or posterior approach. The steps, pitfalls and pearls of this surgical approach will be demonstrated in a detailed video.

The video can be found here: http://youtu.be/-ARTp6g13hgs.

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Alexander G. Weil, Aria Fallah, Evan C. Lewis and Sanjiv Bhatia

OBJECTIVE

Insular lobe epilepsy (ILE) is an under-recognized cause of extratemporal epilepsy and explains some epilepsy surgery failures in children with drug-resistant epilepsy. The diagnosis of ILE usually requires invasive investigation with insular sampling; however, the location of the insula below the opercula and the dense middle cerebral artery vasculature renders its sampling challenging. Several techniques have been described, ranging from open direct placement of orthogonal subpial depth and strip electrodes through a craniotomy to frame-based stereotactic placement of orthogonal or oblique electrodes using stereo-electroencephalography principles. The authors describe an alternative method for sampling the insula, which involves placing insular depth electrodes along the long axis of the insula through the insular apex following dissection of the sylvian fissure in conjunction with subdural electrodes over the lateral hemispheric/opercular region. The authors report the feasibility, advantages, disadvantages, and role of this approach in investigating pediatric insular-opercular refractory epilepsy.

METHODS

The authors performed a retrospective analysis of all children (< 18 years old) who underwent invasive intracranial studies involving the insula between 2002 and 2015.

RESULTS

Eleven patients were included in the study (5 boys). The mean age at surgery was 7.6 years (range 0.5–16 years). All patients had drug-resistant epilepsy as defined by the International League Against Epilepsy and underwent comprehensive noninvasive epilepsy surgery workup. Intracranial monitoring was performed in all patients using 1 parasagittal insular electrode (1 patient had 2 electrodes) in addition to subdural grids and strips tailored to the suspected epileptogenic zone. In 10 patients, extraoperative monitoring was used; in 1 patient, intraoperative electrocorticography was used alone without extraoperative monitoring. The mean number of insular contacts was 6.8 (range 4–8), and the mean number of fronto-parieto-temporal hemispheric contacts was 61.7 (range 40–92). There were no complications related to placement of these depth electrodes. All 11 patients underwent subsequent resective surgery involving the insula.

CONCLUSIONS

Parasagittal transinsular apex depth electrode placement is a feasible alternative to orthogonally placed open or oblique-placed stereotactic methodologies. This method is safe and best suited for suspected unilateral cases with a possible extensive insular-opercular epileptogenic zone.

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Anna Lo Presti, Alexander G. Weil and John Ragheb

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Zachary A. Smith and Richard G. Fessler

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Anna Lo Presti, Alexander G. Weil, Aria Fallah, Eric C. Peterson, Toba N. Niazi and Sanjiv Bhatia

Sickle cell disease (SCD) is an autosomal recessive hematological disorder, characterized by sickling of the red blood cells in response to a hypoxic stress and vaso-occlusive crises. It is associated with moyamoya-like changes on cerebral angiographic imaging in 43% of patients. Cerebral aneurysms, arteriovenous malformations, and dural arteriovenous fistulas (AVFs) have been described in association with SCD and moyamoya disease. However, the description of a pial AVF (pAVF) in a patient with SCD and/or moyamoya formation has not yet been reported. The authors present the case of a 15-year-old boy with SCD-associated moyamoya disease harboring a pAVF who developed a de novo venous aneurysm 8 months after undergoing indirect superficial temporal artery-middle cerebral artery (MCA) bypass that was complicated by bilateral ischemia of the MCA territory. The pAVF was successfully treated with transarterial embolization using Onyx. The authors describe the possible pathophysiological mechanisms and management strategies for this rare occurrence.

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Alexander G. Weil, Aria Fallah, Parthasarathi Chamiraju, John Ragheb and Sanjiv Bhatia

OBJECT

Combining endoscopic third ventriculostomy (ETV) with choroid plexus cauterization (CPC) has been shown to improve the success rate compared with ETV alone in infants (less than 24 months) with hydrocephalus who were treated in developing countries. The authors sought to evaluate the safety and efficacy of this procedure, using a rigid neuroendoscope, in a single North American center, and to assess whether the ETV success score (ETVSS), the CURE Children’s Hospital of Uganda ETVSS (CCHU ETVSS), and other pre- and intraoperative variables could predict success.

METHODS

The authors performed a retrospective review of consecutive ETV/CPC procedures performed using a rigid neuroendoscope to treat infantile hydrocephalus. The infants underwent the procedure at Miami Children’s Hospital between January 2007 and 2014, with at least one postoperative follow-up. Duration of follow-up or time to failure of ETV/CPC, the primary outcome measure, was documented. A repeat CSF diversion procedure or death was considered as a failure of ETV/CPC. The time to event was measured using a Kaplan-Meier analysis. The authors analyzed ETVSS, CCHU ETVSS, and pre- and intraoperative variables to determine their suitability to predict success.

RESULTS

Eighty-five patients (45 boys) with a mean age of 4.3 months (range 1 day to 20 months) underwent ETV/CPC. Etiology included intraventricular hemorrhage of prematurity in 44 patients (51.7%), myelomeningocele (MMC) in 7 (8.2%), congenital aqueductal stenosis in 12 (14.1%), congenital communicating hydrocephalus in 6 (7.1%), Dandy-Walker complex in 6 (7.1%), postinfectious hydrocephalus in 5 (5.8%), and other cause in 5 (5.8%). Six procedure-related complications occurred in 5 (5.8%) patients, including 2 hygromas, 1 CSF leak, and 3 infections. There were 3 mortalities in this cohort. ETV/CPC was successful in 42.1%, 37.7%, and 36.8% of patients at 6, 12, and 24 months follow-up, respectively. The median (95% CI) time to ETV/CPC failure was 4.0 months (0.9–7.1 months). In univariate analyses, both the ETVSS (hazard ratio [HR] 1.03; 95% CI 1.01–1.05; p = 0.004) and CCHU ETVSS (HR 1.48; 95% CI 1.04–2.09; p = .028) were predictive of outcome following ETV/CPC. In multivariate analysis, the presence of prepontine scarring was associated with ETV/CPC failure (HR 0.34; 95% CI 0.19–0.63; p < 0.001). Other variables, such as radiological criteria (prepontine interval, prepontine space, aqueductal stenosis, Third Ventricular Morphology Index) and intraoperative findings (ventriculostomy pulsations, extent of CPC), did not predict outcome.

CONCLUSIONS

ETV/CPC is a feasible alternative to ETV and ventriculoperitoneal shunt in infants with hydrocephalus. Both the ETVSS and CCHU ETVSS predicted success following ETV/CPC in this single-center North American cohort of patients.

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Adil Harroud, Alexander G. Weil, Jean Turgeon, Claude Mercier and Louis Crevier

OBJECT

A major challenge in sagittal craniosynostosis surgery is the high transfusion rate (50%–100%) related to blood loss in small pediatric patients. Several approaches have been proposed to prevent packed red blood cell (PRBC) transfusion, including endoscopic surgery, erythropoietin ortranexamic acid administration, and preoperative hemodilution. The authors hypothesized that a significant proportion of postoperative anemia observed in pediatric patients is actually dilutional. Consequently, since 2005, at CHU Sainte-Justine, furosemide has been administered to correct the volemic status and prevent PRBC transfusion. The purpose of this study was to evaluate the impact of postoperative furosemide administration on PRBC transfusion rates.

METHODS

This was a retrospective study of 96 consecutive patients with sagittal synostosis who underwent surgery at CHU Sainte-Justine between January 2000 and May 2012. The mean age at surgery was 4.9 ± 1.5 months (range 2.8–8.7 months). Patients who had surgery before 2005 constituted the control group. Those who had surgery in 2005 or 2006 were considered part of an implementation phase because furosemide administration was not routine. Patients who had surgery after 2006 were part of the experimental (or furosemide) group. Transfusion rates among the 3 groups were compared. The impact of furosemide administration on transfusion requirement was also measured while accounting for other variables of interest in a multiple logistic regression model.

RESULTS

The total transfusion rate was significantly reduced in the furosemide group compared with the control group (31.3% vs 62.5%, respectively; p = 0.009), mirroring the decrease in the postoperative transfusion rate between the groups (18.3% vs 50.0%, respectively; p = 0.003). The postoperative transfusion threshold remained similar throughout the study (mean hemoglobin 56.0 g/dl vs 60.9 g/dl for control and furosemide groups, respectively; p = 0.085). The proportion of nontransfused patients with recorded hemoglobin below 70 g/dl did not differ between the control and furosemide groups (41.7% vs 28.6%, respectively; p = 0.489). Surgical procedure, preoperative hemoglobin level, estimated blood loss, and furosemide administration significantly affected the risk of receiving a postoperative PRBC transfusion. When these variables were analyzed in a multiple logistic regression model, furosemide administration remained strongly associated with a reduced risk of being exposed to a blood transfusion (OR 0.196, p = 0.005). There were no complications related to furosemide administration.

CONCLUSIONS

A significant part of the postoperative anemia observed in patients who underwent sagittal craniosynostosis surgery was due to hypervolemic hemodilution. Correction of the volemic status with furosemide administration significantly reduces postoperative PRBC transfusion requirements in these patients.