Saleem I. Abdulrauf

Surgery of intraventricular tumors.

The deep location and eloquent surroundings of the ventricular system within the brain have historically posed significant and often formidable challenges for the optimal resection of tumors in these locations. The evolution and advances in microsurgical techniques and neuroanatomic knowledge have led to a general paradigm shift from transcerebral trajectories to transcisternal corridor strategies. The essence of microsurgery of the ventricular system has evolved around the concept of circumnavigating eloquent cortical and white matter structures to achieve minimally invasive access and resection while optimizing functional and cognitive outcomes.

A national fundamentals curriculum for neurosurgery PGY1 residents: The 2010 society of neurological surgeons boot camp courses

BACKGROUND: In July 2009, the Accreditation Council for Graduate Medical Education (ACGME) incorporated postgraduate year 1 (PGY1 intern) level training into all U.S. neurosurgery residency programs. OBJECTIVE: To provide a fundamentals curriculum for all incoming neurosurgery PGY1 residents in ACGME-accredited programs, including skills, knowledge, and attitudes that promote quality, patient safety, and professionalism. METHODS: The Society of Neurological Surgeons organized 6 regional “boot camp” courses for incoming neurosurgery PGY1 residents in July 2010 that consisted of 9 lectures on clinical and nonclinical competencies plus 10 procedural and 6 surgical skills stations. Resident and faculty participants were surveyed to assess knowledge and course effectiveness. RESULTS: A total of 186 of 197 U.S. neurosurgical PGY1 residents (94%) and 75 neurosurgical faculty from 36 of 99 programs (36%) participated in the inaugural boot camp courses. All residents and 83% of faculty participants completed course surveys. All resident and faculty respondents thought that the boot camp courses fulfilled their purpose and objectives and imparted skills and knowledge that would improve patient care. PGY1 residents knowledge of information taught in the courses improved significantly in postcourse testing (P < .0001). Residents and faculty particularly valued simulated and other hands-on skills training. CONCLUSION: Regional organization facilitated an unprecedented degree of participation in a national fundamental skills program for entering neurosurgery residents. One hundred percent of resident and faculty respondents positively reviewed the courses. The boot camp courses may provide a model for enhanced learning, professionalism, and safety at the inception of training in other procedural specialties.

Anterior Ethmoidal Artery: Microsurgical Anatomy and Technical Considerations

OBJECTIVE: Vascular lesions of the anterior cranial fossa can receive significant blood supply from the anterior ethmoidal artery. Embolization of this blood supply exposes the parent vessel, the ophthalmic artery, to possible embolic complications, which can lead to loss of vision. A study of the microsurgical anatomy can help delineate the course of the anterior ethmoidal artery and find the best points for proximal control of the blood supply to these lesions. Clinical cases are presented to illustrate how lesions with prominent anterior ethmoidal artery feeders are best approached through fronto-orbital single-flap craniotomies. METHODS: Eight cadaveric dissections to demonstrate the microsurgical anatomy of the anterior ethmoidal artery were performed to study the relevant anatomy. Two clinical cases are presented that demonstrate clinical application of this anatomy through fronto-orbital single-flap craniotomies. RESULTS: Eight arteries were studied in four cadaveric heads. The dissections show the course of the anterior ethmoidal artery from the ophthalmic artery in the orbit, through the anterior ethmoidal foramen into the ethmoid air cells, to the cribriform plate, where it turns superiorly to become the anterior falx artery. The first surgical case is of a giant tuberculum sellae meningioma that was resected with coagulation and division of the anterior ethmoidal arteries at the anterior ethmoidal foramina at the laminae papyraceae of both medial orbital walls. The second surgical case is of a large deep right frontal arteriovenous malformation that was resected with coagulation and division of the anterior ethmoidal artery at the anterior ethmoidal foramen of the lamina papyracea of the right medial orbital wall. CONCLUSION: The cadaveric dissections and our surgical experience show that the anterior ethmoidal artery has three important sites for surgical access: 1) the anterior ethmoidal foramen at the lamina papyracea of the medial orbital wall; 2) the anterior ethmoid canal at the lateral ethmoid wall; and 3) extradurally, at the cribriform plate. These three sites are best accessed through a fronto-orbital single-flap craniotomy, which can be unilateral or bilateral, depending on the pathological findings. The described orbital-cranial approach in this article is not being advocated to replace the standard pterional and frontal approaches; rather, we suggest it as an option in these complex cases that require early proximal control of the anterior ethmoidal artery feeders.

Short segment internal maxillary artery to middle cerebral artery bypass: a novel technique for extracranial-to-intracranial bypass.

BACKGROUND:Traditional high-flow extracranial-to-intracranial (EC-IC) bypass procedures require a cervical incision and a long (20-25 cm) radial artery or saphenous vein graft. This technical note describes a less invasive, EC-IC bypass technique using a short-segment (8-10 cm) of the radial artery to anastomose the internal maxillary artery (IMAX) to the middle cerebral artery. CLINICAL PRESENTATION:Anatomic dissections were performed on 6 cadaveric specimens to assess the location of the IMAX artery using an extradural middle fossa approach. Subsequently, the procedure was implemented in a patient with a giant fusiform internal carotid artery aneurysm. TECHNIQUE:A straight line was drawn anteriorly from the V2/V3 apex along the inferior edge of V2. The IMAX was found 8.6 mm on average anteriorly from the lateral edge of the foramen rotundum. We drilled to a depth of 4.2 mm on average to find the medial extent of the artery and then lateral and deep drilling exposed an average of 7.8 mm of graft. The IMAX was consistently found running just anterior and parallel to a line between the foramens rotundum and ovale. In the clinical case presented, both intraoperative indocyanine green and postoperative conventional angiography revealed a patent graft. The patient did well clinically without any new deficits. CONCLUSION:The advantages of this new technique include the avoidance of a long cervical incision and potentially higher patency rates secondary to shorter graft length than currently practiced.

Anatomic relationship of the optic radiations to the atrium of the lateral ventricle: description of a novel entry point to the trigone.

OBJECTIVE The aim of this study was to delineate the anatomic relationship of the optic radiations to the atrium of the lateral ventricle using the Klingler method of white matter fiber dissection. These findings were applied to define a surgical approach to the trigone that avoids injury to the optic radiations. METHODS Sixteen cadaveric hemispheres were prepared by several cycles of freezing and thawing. With the use of wooden spatulas, the specimens were dissected in a stepwise fashion. Each hemisphere was dissected first from a lateromedial direction and then from a mediolateral approach, and careful attention was given to the course and direction of the optic radiation fibers at all points from Meyers loop to their termination at the cuneus and the lingual gyrus. RESULTS In all 16 dissected hemispheres, the following observations were made: 1) the entire lateral wall of the lateral ventricle—from the temporal horn to the trigone to the occipital horn—is covered by the optic radiations; and 2) the medial wall of the lateral ventricle in the area of the trigone is entirely free of the optic radiations. CONCLUSION The results of this study confirm that the medial parieto-occipital interhemispheric approach to the ventricular trigone will avoid injury to the optic radiations and the calcarine cortex. The authors describe the most direct trajectory to the ventricular trigone using this approach and propose a point of entry that transects the cingulate gyrus at a point 5 mm superior and 5 mm posterior to the falcotentorial junction.

Age-Associated Vasospasm in Aneurysmal Subarachnoid Hemorrhage

The relationship between age and vasospasm caused by subarachnoid hemorrhage (SAH) is controversial. We evaluated this relationship in a contemporary sample from a single institution. In a retrospective study design, we included patients with SAH caused by ruptured intracranial aneurysms. All patients underwent an evaluation that included head imaging, cerebral angiography, and treatment for the underlying aneurysm. Vasospasm was classified as absent, any vasospasm, or symptomatic vasospasm. Age was classified into 2 categories with a cutoff of 50 years, and also was stratified by decade. All patients had received preventative and therapeutic measures for vasospasm. Logistic regression analysis was used to assess the association between age and the occurrence of vasospasm. A total of 108 patients were included in this analysis, 67 of whom were age ≥50 years. The older patients had a higher incidence of vascular risk factors, and the younger patients had a higher incidence of smoking and illicit substance abuse. The mean age of the patients with any vasospasm (n = 41) was 48.51 ± 11.23 years, compared with 59.67 ± 13.30 years in those without vasospasm (P < .0001). Adjusted analysis found a greater risk of vasospasm in the younger patients compared with the older patients (odds ratio, 5.83; 95% confidence interval, 2.41-14.12 for any vasospasm; odds ratio, 2.66; 95% confidence interval, 1.008-7.052 for symptomatic vasospasm). This risk of vasospasm decreased with advanced age (P < .0001). Our findings suggest that patients age <50 years are at 5-fold greater risk of any vasospasm compared with older patients, and that age-adjusted prevention protocols may need to be considered.

Meckel's Cave

OBJECTIVEnTo review the microsurgical anatomy of Meckels cave, a detailed knowledge of which is a prerequisite to devising an appropriate surgical strategy and performing successful surgery.nnnMETHODSnThe microsurgical anatomy of Meckels cave was studied under an operating microscope in 15 human cadaver heads (30 sides). To understand the meningeal architecture and the cross-sectional anatomy of Meckels cave, serial histologic sections were made in an additional adult human cadaver specimen.nnnRESULTSnMeckels cave is a natural mouth-shaped aperture connecting with the posterior fossa that is located in the medial portion of the middle cranial fossa. The cave extends forward similar to an open-ended three-fingered glove and provides a channel for the rootlets of the trigeminal nerve; the trigeminal ganglion; and the ophthalmic (cranial nerve V(1)), maxillary (cranial nerve V(2)), and mandibular (cranial nerve V(3)) divisions until they reach their respective foramina. The average height of this oval mouth was found to be 4.2 mm (range 3-5 mm) and the average width was 7.6 mm (range 6-8 mm). The mouth of Meckels cave was located 12 mm (range 10-15 mm) superior and medial to the internal acoustic meatus and 6.5 mm (range 5-8 mm) superior and medial to the dural point of entrance of the nervus abducens and 20 mm (range 18-23 mm) medial to the arcuate eminence.nnnCONCLUSIONSnDetailed and sound knowledge of the microsurgical anatomy of Meckels cave, which borders on surgically important structures, such as the internal carotid artery and cavernous sinus, is essential to performing precise microneurosurgery in this region. This study describes the complex anatomy of Meckels cave and surrounding structures to provide the knowledge needed to devise a more complete surgical strategy and establish accurate orientation during the surgical procedure.

Sumatriptan Can Alleviate Headaches Due to Carotid Artery Dissection

Cluster headaches can be mimicked by a spontaneous carotid artery dissection. We report a 45‐year‐old man with a spontaneous carotid artery dissection whose unilateral headache responded to sumatriptan. An oral dose of 50 mg of sumatriptan relieved 90% of the pain after 2 hours. A second dose the next day achieved similar results within 4 hours. The diagnosis of dissection was made later by magnetic resonance angiogram and conventional angiography. This case illustrates that a positive response to a triptan can not be used to distinguish the first attack of cluster headache from a carotid artery dissection.

Localization of the Internal Maxillary Artery for Extracranial-to-Intracranial Bypass through the Middle Cranial Fossa: A Cadaveric Study

The internal maxillary artery (IMAX) is a promising arterial pedicle to function as a donor vessel for extracranial-to-intracranial (EC-IC) bypass procedures. The access to the IMAX through the anterior portion of the middle cranial fossa floor allows a much shorter interposition graft to be used to create a bypass to the ipsilateral middle cerebral artery and prevents a second incision in the neck. One of the challenges of this technique, however, is the difficulty to find the IMAX through an intracranial approach. The purpose of this cadaveric study is to establish a reliable method to localize the IMAX through a middle fossa floor approach based on skull base bone landmarks. In this study 5 latex-injected fixated cadaveric specimens were dissected bilaterally (providing a total of 10 IMAX dissections) to determine the precise location of the IMAX in the pterygopalatine fossa in relationship to bone landmarks of the middle fossa floor as seen through an intracranial approach. Drilling of the middle fossa floor was undertaken through both the originally described anteromedial approach, and a new anterolateral approach. Measurements were taken correlating the position of the IMAX to ipsilateral foramen rotundum, ipsilateral foramen ovale, posterior wall of the maxillary sinus, and distal V2 branches. Median and standard deviation were calculated for each dataset. The IMAX was found, within the pterygopalatine fossa, by drilling the greater wing of the sphenoid bone on average 10 mm anteriorly and 5 mm laterally to foramen rotundum, at an average depth of 8 mm. The IMAX was also found inferiorly to the maxillary nerve and laterally to the pterygoid head of the lateral pterygoid muscle. A more laterally oriented approach, consisting of drilling the greater wing of the sphenoid bone from a point perpendicular to foramen rotundum posteriorly to the sphenotemporal suture anteriorly, allowed for a longer segment of the IMAX to be easily identified and exposed facilitating its use as a donor vessel in bypass procedures. This cadaveric study provides a reliable and reproducible set of measurements to localize the IMAX within the pterygopalatine fossa through an intracranial middle fossa approach. The ability to find the IMAX consistently is an important step in exploring the possibility of using the IMAX as a routine donor vessel for EC-IC bypass procedures.

Proposed clinical internal carotid artery classification system.

Introduction: Numerical classification systems for the internal carotid artery (ICA) are available, but modifications have added confusion to the numerical systems. Furthermore, previous classifications may not be applicable uniformly to microsurgical and endoscopic procedures. The purpose of this study was to develop a clinically useful classification system. Materials and Methods: We performed cadaver dissections of the ICA in 5 heads (10 sides) and evaluated 648 internal carotid arteries with computed tomography angiography. We identified specific anatomic landmarks to define the beginning and end of each ICA segment. Results: The ICA was classified into eight segments based on the cadaver and imaging findings: (1) Cervical segment; (2) cochlear segment (ascending segment of the ICA in the temporal bone) (relation of the start of this segment to the base of the styloid process: Above, 425 sides [80%]; below, 2 sides [0.4%]; at same level, 107 sides [20%];P< 0.0001) (relation of cochlea to ICA: Posterior, 501 sides [85%]; posteromedial, 84 sides [14%];P< 0.0001); (3) petrous segment (horizontal segment of ICA in the temporal bone) starting at the crossing of the eustachian tube superolateral to the ICA turn in all 10 samples; (4) Gasserian-Clival segment (ascending segment of ICA in the cavernous sinus) starting at the petrolingual ligament (PLL) (relation to vidian canal on imaging: At same level, 360 sides [63%]; below, 154 sides [27%]; above, 53 sides [9%];P< 0.0001); in this segment, the ICA projected medially toward the clivus in 275 sides (52%) or parallel to the clivus with no deviation in 256 sides (48%;P< 0.0001); (5) sellar segment (medial loop of ICA in the cavernous sinus) starting at the takeoff of the meningeal hypophyseal trunk (ICA was medial into the sella in 271 cases [46%], lateral without touching the sella in 127 cases [23%], and abutting the sella in 182 cases [31%];P< 0.0001); (6) sphenoid segment (lateral loop of ICA within the cavernous sinus) starting at the crossing of the fourth cranial nerve on the lateral aspect of the cavernous ICA and located directly lateral to the sphenoid sinus; (7) ring segment (ICA between the 2 dural rings) starting at the crossing of the third cranial nerve on the lateral aspect of the ICA; (8) cisternal segment starting at the distal dural ring. Conclusions: The classification may be applied uniformly to all skull base surgical approaches including lateral microsurgical and ventral endoscopic approaches, obviating the need for 2 separate classification systems. The classification allows extrapolation of relevant clinical information because each named segment may indicate potential surgical risk to specific structures.