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Sophia F. Shakur, Ali Alaraj, Nasya Mendoza-Elias, Muhammad Osama, and Fady T. Charbel

OBJECTIVE

The pathogenesis of cerebral aneurysms in patients with internal carotid artery (ICA) occlusion is hypothesized to be hemodynamic. For the first time, the authors quantify the hemodynamic characteristics associated with aneurysm formation in patients with ICA occlusion.

METHODS

Records of patients with unilateral ICA stenosis or occlusion ≥ 90% who underwent hemodynamic assessment before treatment using quantitative MR angiography were retrospectively reviewed. The patients were classified into 2 groups based on the presence or absence of aneurysms. The hemodynamic parameters of flow volume rate, flow velocity, and wall shear stress (WSS) were measured in each vessel supplying collateral flow—bilateral A1 segments and bilateral posterior communicating arteries—and then compared between the groups.

RESULTS

A total of 36 patients were included (8 with and 28 without aneurysms). The mean flow (72.3 vs 48.9 ml/min, p = 0.10), flow velocity (21.1 vs 12.7 cm/sec, p = 0.006), and WSS (22.0 vs 12.3 dynes/cm2, p = 0.003) were higher in the A1 segment contralateral to the side of the patent ICA in patients with versus without aneurysms. All de novo or growing aneurysms in our cohort were located on the anterior communicating artery (ACoA) or P1 segment.

CONCLUSIONS

Flow velocity and WSS are significantly higher across the ACoA in patients who harbor an aneurysm, and de novo or growing aneurysms are often located on collateral vessels. Thus, robust primary collaterals after ICA occlusion may be a contributing factor in cerebral aneurysm formation.

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Kenan I. Arnautovic, Ossama Al-Mefty, T. Glenn Pait, Ali F. Krisht, and Muhammad M. Husain

The authors studied the microsurgical anatomy of the suboccipital region, concentrating on the third segment (V3) of the vertebral artery (VA), which extends from the transverse foramen of the axis to the dural penetration of the VA, paying particular attention to its loops, branches, supporting fibrous rings, adjacent nerves, and surrounding venous structures.

Ten cadaver heads (20 sides) were fixed in formalin, their blood vessels were perfused with colored silicone rubber, and they were dissected under magnification. The authors subdivided the V3 into two parts, the horizontal (V3h) and the vertical (V3v), and studied the anatomical structures topographically, from the superficial to the deep tissues. In two additional specimens, serial histological sections were acquired through the V3 and its encircling elements to elucidate their cross-sectional anatomy. Measurements of surgically and clinically important features were obtained with the aid of an operating microscope.

This study reveals an astonishing anatomical resemblance between the suboccipital complex and the cavernous sinus, as follows: venous cushioning; anatomical properties of the V3 and those of the petrous-cavernous internal carotid artery (ICA), namely their loops, branches, supporting fibrous rings, and periarterial autonomic neural plexus; adjacent nerves; and skull base locations. Likewise, a review of the literature showed a related embryological development and functional and pathological features, as well as similar transitional patterns in the arterial walls of the V3 and the petrous-cavernous ICA. Hence, due to its similarity to the cavernous sinus, this suboccipital complex is here named the "suboccipital cavernous sinus." Its role in physiological and pathological conditions as they pertain to various clinical and surgical implications is also discussed.

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Kenan I. Arnautović, Ossama Al-Mefty, T. Glenn Pait, Ali F. Krisht, and Muhammad M. Husain

✓ The authors studied the microsurgical anatomy of the suboccipital region, concentrating on the third segment (V3) of the vertebral artery (VA), which extends from the transverse foramen of the axis to the dural penetration of the VA, paying particular attention to its loops, branches, supporting fibrous rings, adjacent nerves, and surrounding venous structures.

Ten cadaver heads (20 sides) were fixed in formalin, their blood vessels were perfused with colored silicone rubber, and they were dissected under magnification. The authors subdivided the V3 into two parts, the horizontal (V3h) and the vertical (V3v), and studied the anatomical structures topographically, from the superficial to the deep tissues. In two additional specimens, serial histological sections were acquired through the V3 and its encircling elements to elucidate their cross-sectional anatomy. Measurements of surgically and clinically important features were obtained with the aid of an operating microscope.

This study reveals an astonishing anatomical resemblance between the suboccipital complex and the cavernous sinus, as follows: venous cushioning; anatomical properties of the V3 and those of the petrous—cavernous internal carotid artery (ICA), namely their loops, branches, supporting fibrous rings, and periarterial autonomic neural plexus; adjacent nerves; and skull base locations. Likewise, a review of the literature showed a related embryological development and functional and pathological features, as well as similar transitional patterns in the arterial walls of the V3 and the petrous-cavernous ICA. Hence, due to its similarity to the cavernous sinus, this suboccipital complex is here named the “suboccipital cavernous sinus.” Its role in physiological and pathological conditions as they pertain to various clinical and surgical implications is also discussed.

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Marcus Czabanka, Muhammad Ali, Peter Schmiedek, Peter Vajkoczy, and Michael T. Lawton

Endovascular occlusion of hemorrhagic dissecting aneurysms of the vertebral artery (VA) is not possible when the posterior inferior cerebellar artery (PICA) originates from the dissecting aneurysm or when the contralateral VA provides inadequate collateral blood flow to the distal basilar circulation. The authors introduce a VA-PICA bypass with radial artery interposition graft and aneurysm trapping as an alternative approach and describe 2 cases in which this bypass was used to treat hemorrhagic dissecting VA aneurysms.

The VA-PICA bypass is performed via a standard far lateral approach. An end-to-side anastomosis between the radial artery graft and the PICA at the level of the caudal loop is performed first, and an end-to-side anastomosis is performed between the V3 segment and the proximal end of the radial artery graft. A 56-year-old woman harbored a hemorrhagic dissecting VA aneurysm incorporating the origin of the PICA. Endovascular treatment failed, with aneurysm refilling on follow-up angiography. A 65-year-old man had a hemorrhagic dissecting VA aneurysm and a hypoplastic contralateral VA. Both patients were treated with the VA-PICA bypass and aneurysm trapping, with adequate filling of the PICA territory in the first patient and both the PICA territory and the basilar circulation in the second patient.

Vertebral artery–PICA bypass with radial artery interposition graft and subsequent trapping of the dissected VA segment is an alternative to occipital artery–PICA and PICA-PICA bypass for the treatment of hemorrhagic dissecting VA aneurysms that are not suitable for endovascular occlusion.

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Peter S. Amenta, Muhammad S. Ali, Aaron S. Dumont, L. Fernando Gonzalez, Stavropoula I. Tjoumakaris, David Hasan, Robert H. Rosenwasser, and Pascal Jabbour

Intravenous and intraarterial recombinant tissue plasminogen activator remains underutilized in the treatment of acute ischemic stroke, largely due to strict adherence to the concept of the therapeutic time window for administration. Recent efforts to expand the number of patients eligible for thrombolysis have been mirrored by an evolution in endovascular recanalization technology and techniques. As a result, there is a growing need to establish efficient and reliable means by which to select candidates for endovascular intervention beyond the traditional criteria of time from symptom onset. Perfusion imaging techniques, particularly CT perfusion used in combination with CT angiography, represent an increasingly recognized means by which to identify those patients who stand to benefit most from endovascular recanalization. Additionally, CT perfusion and CT angiography appear to provide sufficient data by which to exclude patients in whom there is little chance of neurological recovery or a substantial risk of postprocedure symptomatic intracranial hemorrhage. The authors review the current literature as it pertains to the limitations of time-based selection of patients for intervention, the increasing utilization of endovascular therapy, and the development of a CT perfusion-based selection of acute stroke patients for endovascular recanalization. Future endeavors must prospectively evaluate the utility and safety of CT perfusion-based selection of candidates for endovascular intervention.

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Kevin Paul Ferraris, Hideaki Matsumura, Dewa Putu Wisnu Wardhana, Theodor Vesagas, Kenny Seng, Mohd Raffiz Mohd Ali, Eiichi Ishikawa, Akira Matsumura, Rohadi Muhammad Rosyidi, Tjokorda Mahadewa, and Meng-Fai Kuo

OBJECTIVE

The authors, who are from Indonesia, Japan, Malaysia, the Philippines, and Taiwan, sought to illustrate the processes of training neurosurgeons in their respective settings by presenting data and analyses of the current state of neurosurgical education across the East Asian region.

METHODS

The authors obtained quantitative data as key indicators of the neurosurgical workforce from each country. Qualitative data analysis was also done to provide a description of the current state of neurosurgical training and education in the region. A strengths, weaknesses, opportunities, and threats (SWOT) analysis was also done to identify strategies for improvement.

RESULTS

The number of neurosurgeons in each country is as follows: 370 in Indonesia, 10,014 in Japan, 152 in Malaysia, 134 in the Philippines, and 639 in Taiwan. With a large neurosurgical workforce, the high-income countries Japan and Taiwan have relatively high neurosurgeon to population ratios of 1 per 13,000 and 1 per 37,000, respectively. In contrast, the low- to middle-income countries Indonesia, Malaysia, and the Philippines have low neurosurgeon to population ratios of 1 per 731,000, 1 per 210,000, and 1 per 807,000, respectively. In terms of the number of training centers, Japan has 857, Taiwan 30, Indonesia 7, Malaysia 5, and the Philippines 10. In terms of the number of neurosurgical residents, Japan has 1000, Taiwan 170, Indonesia 199, Malaysia 53, and the Philippines 51. The average number of yearly additions to the neurosurgical workforce is as follows: Japan 180, Taiwan 27, Indonesia 10, Malaysia 4, and the Philippines 3. The different countries included in this report have many similarities and differences in their models and systems of neurosurgical education. Certain important strategies have been formulated in order for the system to be responsive to the needs of the catchment population: 1) establishment of a robust network of international collaboration for reciprocal certification, skills sharing, and subspecialty training; 2) incorporation of in-service residency and fellowship training within the framework of improving access to neurosurgical care; and 3) strengthening health systems, increasing funding, and developing related policies for infrastructure development.

CONCLUSIONS

The varied situations of neurosurgical education in the East Asian region require strategies that take into account the different contexts in which programs are structured. Improving the education of current and future neurosurgeons becomes an important consideration in addressing the health inequalities in terms of access and quality of care afflicting the growing population in this region of the world.

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Alireza Mansouri, Shervin Taslimi, Aram Abbasian, Jetan H. Badhiwala, Muhammad Ali Akbar, Naif M. Alotaibi, Saleh A. Almenawer, Alexander G. Weil, Aria Fallah, Lionel Carmant, and George M. Ibrahim

OBJECTIVE

The aim of this study was to describe the current state of epilepsy surgery and establish estimates of seizure outcomes following surgery for medically intractable epilepsy (MIE) in low- and middle-income countries (LMICs).

METHODS

The MEDLINE and Embase databases were searched without publication date restriction. This search was supplemented by a manual screen of key epilepsy and neurosurgical journals (January 2005 to December 2016). Studies that reported outcomes for at least 10 patients of any age undergoing surgery for MIE in LMICs over a defined follow-up period were included. A meta-analysis with a random-effects model was performed in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement and MOOSE (Meta-analysis of Observational Studies in Epidemiology) guidelines. Pooled estimates of seizure freedom and favorable seizure outcomes following anterior temporal lobectomy with or without amygdalohippocampectomy (ATL ± AH) were reported.

RESULTS

Twenty studies were selected, of which 16 were from Asian centers. The average age at surgery in all studies was less than 30 years, and the average preoperative duration of epilepsy ranged from 3 to 16.1 years. Mesial temporal sclerosis accounted for 437 of 951 described pathologies, and 1294 of the 1773 procedures were ATL ± AH. Based on 7 studies (646 patients) the pooled seizure freedom estimate following ATL ± AH was 68% (95% CI 55%–82%). Based on 8 studies (1096 patients), the pooled estimate for favorable seizure outcomes was 79% (95% CI 74%–85%).

CONCLUSIONS

Surgery for MIE in LMICs shows a high percentage of seizure freedom and favorable outcomes. These findings call for a concerted global effort to improve timely access to surgery for MIE patients in these regions, including investments aimed at refining existing and establishing additional centers.

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Muhammad Ali, Nek Asghar, Adam Li, Theodore Hannah, Zachary Spiera, Naoum Fares Marayati, Nickolas Dreher, John Durbin, Alex Gometz, Mark Lovell, and Tanvir Choudhri

OBJECTIVE

Concussions in youth sports comprise an estimated 1.6–3.8 million annual injuries in the US. Sex, age, and attention-deficit hyperactivity disorder (ADHD) have been identified as salient risk factors for concussion. This study seeks to evaluate the role of premorbid depression or anxiety (DA), with or without antidepressant use, on the incidence of concussion and the recovery of symptoms and neurocognitive dysfunction after concussion.

METHODS

Immediate Postconcussion Assessment and Cognitive Testing (ImPACT) was administered to 7453 youth athletes at baseline. Throughout the season, concussions were examined by physicians and athletic trainers, followed by readministration of ImPACT postinjury (PI) and again at follow-up, a median of 7 days PI. Individuals were divided into three categories: 1) unmedicated athletes with DA (DA-only, n = 315), athletes taking antidepressants (DA-meds, n = 81), and those without DA or antidepressant use (non-DA, n = 7039). Concussion incidence was calculated as the total number of concussions per total number of patient-years. The recovery of neurocognitive measures PI was calculated as standardized deviations from baseline to PI and then follow-up in the 5 composite ImPACT scores: symptom score, verbal memory, visual memory, visual motor skills, and reaction time. Univariate results were confirmed with multivariate analysis.

RESULTS

There was no difference in concussion incidence between the DA-only cohort and the non-DA group. However, the DA-meds group had a significantly greater incidence of concussion than both the DA-only group (OR 2.67, 95% CI 1.88–7.18, p = 0.0001) and the non-DA group (OR 2.19, 95% CI 1.16–4.12, p = 0.02). Deviation from baseline in PI symptom scores was greater among the DA-meds group as compared to the non-DA group (OR 1.14, 95% CI 1.01–1.28, p = 0.03). At follow-up, the deviation from baseline in symptom scores remained elevated among the DA-meds group as compared to the non-DA group (OR 1.62, 95% CI 1.20–2.20, p = 0.002) and the DA-only group (OR 1.87, 95% CI 1.12–3.10, p = 0.02). Deviation from baseline in follow-up verbal memory was also greater among the DA-meds group as compared to both the non-DA group (OR 1.57, 95% CI 1.08–2.27, p = 0.02) and the DA-only group (OR 1.66, 95% CI 1.03–2.69, p = 0.04).

CONCLUSIONS

Premorbid DA itself does not seem to affect the incidence of concussion or the recovery of symptoms and neurocognitive dysfunction PI. However, antidepressant use for DA is associated with 1) increased concussion incidence and 2) elevated symptom scores and verbal memory scores up to 7 days after concussion, suggesting impaired symptomatic and neurocognitive recovery on ImPACT.