Search Results

You are looking at 1 - 10 of 45 items for

  • Author or Editor: Nader Sanai x
Clear All Modify Search
Free access

Michael A. Mooney and Nader Sanai

The contralateral interhemispheric approach has several advantages for approaching parasagittal lesions, including lesions involving or approaching the medial precentral gyrus. Supplementing the interhemispheric approach with asleep motor mapping is useful for confirming the location of the corticospinal tracts from the contralateral transfalcine corridor and identifying subcortical motor fibers at the deep aspect of the resection cavity. The authors describe the contralateral interhemispheric, transfalcine approach with asleep motor mapping to resect a parasagittal metastatic lesion involving the medial precentral gyrus.

The video can be found here: https://youtu.be/L-fJ6m5kOWs.

Full access

Nader Sanai and Mitchel S. Berger

Although a primary tenet of neurosurgical oncology is that survival can improve with greater tumor resection, this principle must be tempered by the potential for functional loss following a radical removal. Preoperative planning with functional and physiological imaging paradigms, combined with intraoperative strategies such as cortical and subcortical stimulation mapping, can effectively reduce the risks associated with operating in eloquent territory. In addition to identifying critical motor pathways, these techniques can be adapted to identify language function reliably. The authors review the technical nuances of intraoperative mapping for low- and high-grade gliomas, demonstrating their efficacy in optimizing resection even in patients with negative mapping data. Collectively, these surgical strategies represent the cornerstone for operating on gliomas in and around functional pathways.

Restricted access

Robert F. Spetzler and Nader Sanai

Object

Smaller operative exposures, endoscopic approaches, and minimally invasive neurosurgery have emerged as a dominant trend in the modern era. In keeping with this evolution, the authors have recently eliminated the use of fixed retractors, instead employing dynamic retraction, with the use of handheld instruments. In the present study, the authors report the results of applying this strategy to challenging vascular and skull base lesions.

Methods

This 6-month study prospectively analyzed the use of retractorless surgery in a consecutive series of 223 patients with intracranial vascular or skull base lesions undergoing craniotomy. A single surgeon performed all operations.

Results

The microsurgical approaches (in descending order of frequency) included an orbitozygomatic craniotomy (77 patients [35%]), frontal (36 patients [16%]), retrosigmoid (27 patients [12%]), interhemispheric (16 patients [7%]), and lateral supracerebellar (15 patients [7%]). The most common lesions were aneurysms (83 lesions overall [37%]), 18 of which required a bypass. Of 159 vascular lesions, there were also 46 cavernous malformations (29%). Meningiomas were the most common skull base tumors (37 cases [58%]). Of the 223 patients, 7 cases of various vascular and skull base lesions required fixed retraction. Therefore, 97% of the cases were successfully treated without a self-retaining retractor system.

Conclusions

Fixed retraction can be supplanted by dynamic retraction with surgical instruments, limiting the risk of retractor-induced tissue edema and injury. This quiet revolution has precipitated a major change in surgical techniques. Extensive dissection of arachnoidal planes, careful placement of the handheld suction device, patient positioning that enhances gravity retraction, the refinement of microsurgical instrumentation, and appropriate selection of the operative corridor all serve to obviate the need for fixed retraction in most intracranial procedures. Retractorless neurosurgery is an achievable goal, even when complex lesions of the vasculature and skull base are being treated.

Restricted access

Nader Sanai and Michael W. McDermott

Object

Resecting large meningiomas along the posterior fossa convexity or cerebellopontine angle (CPA) through a suboccipital approach can be challenging. Limitations include a restricted angle of view, high venous pressures, and suboptimal brain relaxation. While a far-lateral craniotomy is a viable alternative, the risks associated with condylar resection are undesirable.

Methods

The authors retrospectively evaluated a modified far-lateral approach in a consecutive series of 12 patients with large or giant posterior fossa convexity and CPA meningiomas. This approach incorporates transverse-sigmoid sinus exposure and C-1 laminectomy, but there is no condylar resection.

Results

Between January 2006 and February 2008, 12 patients (mean age 52 years) presented with large or giant meningiomas of the posterior fossa convexity or CPA. The mean tumor volume was 72.6 cm3 (range 8–131 cm3). Signs and symptoms at presentation included headache (in 8 patients), cranial neuropathy (in 4), and progressive hemiparesis (in 4). There were no operative complications, and the majority of patients (9) had Simpson Grade I or II resections. There were no new permanent neurological deficits following resection, although 2 patients (17%) had transient deficits. The mean modified Rankin score decreased from 2.2 preoperatively to 0.6 postoperatively.

Conclusions

A modified far-lateral approach to the posterior fossa and CPA allows for safe, and often total, resection of large meningiomas with minimal morbidity. While avoiding the risks of condylar resection, this microsurgical strategy allows for greater field of view, minimal venous bleeding, and immediate access to the spinal subarachnoid space.

Restricted access

Nader Sanai, Susan Chang and Mitchel S. Berger

In recent years, advances in the understanding of low-grade glioma (LGG) biology have driven new paradigms in molecular markers, diagnostic imaging, operative techniques and technologies, and adjuvant therapies. Taken together, these developments are collectively pushing the envelope toward improved quality of life and survival. In this article, the authors evaluate the recent literature to synthesize a comprehensive review of LGGs in the modern neurosurgical era.

Full access

Nader Sanai and Mitchel S. Berger

Restricted access

Zaman Mirzadeh, Nader Sanai and Michael T. Lawton

The authors introduce the azygos anterior cerebral artery (ACA) bypass as an option for revascularizing distal ACA territories, as part of a strategy to trap giant anterior communicating artery (ACoA) aneurysms. In this procedure, the aneurysm is exposed with an orbitozygomatic-pterional craniotomy and distal ACA vessels are exposed with a bifrontal craniotomy. The uninvolved contralateral A2 segment of the ACA serves as a donor vessel for a short radial artery graft. The contralateral pericallosal artery (PcaA) and the callosomarginal artery (CmaA) are connected to the graft in the interhemispheric fissure using the double reimplantation technique. Three anastomoses create an azygos system supplying the entire ACA territory, enabling the surgeon to trap the aneurysm incompletely. Retrograde flow from the CmaA supplies the ipsilateral recurrent artery of Heubner, and the aneurysm lumen thromboses.

The azygos bypass was successfully performed to treat a 47-year-old woman with a giant, thrombotic ACoA aneurysm supplied by the A1 segment of the left ACA, with left PcaA and CmaA originating from the aneurysm base.

The authors conclude that the azygos ACA bypass is a novel option for revascularizing PcaA and CmaA, as part of the overall treatment of giant ACoA aneurysms.

Restricted access

Giuseppe Lanzino

Restricted access

Nader Sanai, Juan Martino and Mitchel S. Berger

Object

The impact of parietal lobe gliomas is typically studied in the context of parietal lobe syndromes. However, critical language pathways traverse the parietal lobe and are susceptible during tumor resection. The authors of this study reviewed their experience with parietal gliomas to characterize the impact of resection and the morbidity associated with language.

Methods

The study population included adults who had undergone resection of parietal gliomas of all grades. Tumor location was identified according to a proposed classification system for parietal region gliomas. Low- and high-grade tumors were volumetrically analyzed using FLAIR and T1-weighted contrast-enhanced MR imaging.

Results

One hundred nineteen patients with parietal gliomas were identified—34 with low-grade gliomas and 85 with high-grade gliomas. The median patient age was 45 years, and most patients (53) presented with seizures, whereas only 4 patients had an appreciable parietal lobe syndrome. The median preoperative tumor volume was 31.3 cm3, the median extent of resection was 96%, and the median postoperative tumor volume was 0.9 cm3. Surprisingly, the most common early postoperative neurological deficit was dysphasia (16 patients), not weakness (12 patients), sensory deficits (14 patients), or parietal lobe syndrome (10 patients). A proposed parietal glioma classification system, based on surgical anatomy, was predictive of language deficits.

Conclusions

This is the largest reported experience with parietal lobe gliomas. The findings suggested that parietal language pathways are compromised at a surprisingly high rate. The proposed parietal glioma classification system is predictive of postoperative morbidity associated with language and can assist with preoperative planning. Taken together, these data emphasize the value of identifying language pathways when operating within the parietal lobe.