Emad Aboud

Skull base tumor model

OBJECT Resident duty-hours restrictions have now been instituted in many countries worldwide. Shortened training times and increased public scrutiny of surgical competency have led to a move away from the traditional apprenticeship model of training. The development of educational models for brain anatomy is a fascinating innovation allowing neurosurgeons to train without the need to practice on real patients and it may be a solution to achieve competency within a shortened training period. The authors describe the use of Stratathane resin ST-504 polymer (SRSP), which is inserted at different intracranial locations to closely mimic meningiomas and other pathological entities of the skull base, in a cadaveric model, for use in neurosurgical training. METHODS Silicone-injected and pressurized cadaveric heads were used for studying the SRSP model. The SRSP presents unique intrinsic metamorphic characteristics: liquid at first, it expands and foams when injected into the desired area of the brain, forming a solid tumorlike structure. The authors injected SRSP via different passages that did not influence routes used for the surgical approach for resection of the simulated lesion. For example, SRSP injection routes included endonasal transsphenoidal or transoral approaches if lesions were to be removed through standard skull base approach, or, alternatively, SRSP was injected via a cranial approach if the removal was planned to be via the transsphenoidal or transoral route. The model was set in place in 3 countries (US, Italy, and The Netherlands), and a pool of 13 physicians from 4 different institutions (all surgeons and surgeons in training) participated in evaluating it and provided feedback. RESULTS All 13 evaluating physicians had overall positive impressions of the model. The overall score on 9 components evaluated--including comparison between the tumor model and real tumor cases, perioperative requirements, general impression, and applicability--was 88% (100% being the best possible achievable score where the evaluator strongly agreed with the proposed factor). Individual components had scores at or above 80% (except for 1). The only score that was below 80% was related to radiographic visibility of the model for adequate surgical planning (score of 74%). The highest score was given to usefulness in neurosurgical training (98%). CONCLUSIONS The skull base tumor model is an effective tool to provide more practice in preoperative planning and technical skills.

Giant intracranial epidermoids: is total removal feasible?

OBJECT Epidermoid tumors arise from misplaced squamous epithelium and enlarge through the accumulation of desquamated cell debris. Optimal treatment consists of total removal of the capsule; therefore, giant and multicompartmental tumors are particularly challenging. A conservative attitude in handling the tumor capsule is common given concerns about capsule adherence to neurovascular structures, and thus the possibility of recurrence is accepted with the intent of minimizing complications. This study focuses on the outcome of surgery in patients with giant epidermoid tumors for which total capsule removal was the aim. METHODS The authors conducted a retrospective analysis of all patients with giant epidermoid tumors treated by the senior author (O.A.), who pursued total removal of the capsule through skull base approaches. Patients were divided into 2 groups: one including patients with de novo tumors and the other consisting of patients who presented with recurrent tumors. RESULTS Thirty-four patients had undergone 46 operations, and the senior author performed 38 of these operations in the study period. The average tumor dimensions were 55 × 36 mm, and 25 tumors had multicompartmental extensions. Total removal of the tumor and capsule was achieved with the aid of the microscope in 73% of the 26 de novo cases but in only 17% of the 12 recurrent tumor cases. The average follow-up among all patients was 111 months (range 10-480 months), and the average postsurgical follow-up was 56.8 months (range 6-137 months). There were 4 recurrences in the de novo group, and every case had had a small piece of tumor capsule left behind. One patient died after delayed rupture of a pseudoaneurysm. In the de novo group, the average preoperative Karnofsky Performance Scale (KPS) score was 71.42%, which improved to 87.14% on long-term follow-up. In the group with recurrences, the KPS score also improved on long-term follow-up, from 64.54% to 84.54%. In the de novo group, 3 cases (11.5%) had permanent cranial nerve deficits, and 4 cases (15.4%) had a CSF leak. In the recurrence group, 3 cases (25%) had new, permanent cranial nerve deficits, and 1 (8.3%) had a CSF leak. Two patients in this group developed hydrocephalus and required a shunt. CONCLUSIONS Total removal of the capsule of giant epidermoid tumors was achieved in 73% of patients with de novo tumors and was associated with improved function, low morbidity and mortality, and a lower risk of recurrence. Surgery in patients with recurrent tumors was associated with higher morbidity and persistence of the disease.

Biocompatible Amniotic Sac Implant Maintains a Scar-Free Brain Surface During Recurrent Glioma Surgery

BACKGROUND Dissection of brain surface adhesions during recurrent glioma surgery carries a risk of injury to cortical vessels and important surface vessels. We present our experience with the use of BioD film, a biocompatible amniotic membrane implant, to help prevent postoperative adhesions. We describe a novel method for preventing postoperative adhesions after high-grade glioma surgery using BioD film. METHODS Amniotic sac implants were laid on the brain surface after resection of gliomas located near major surface arteries (sylvian fissure) and major veins (parasagittal convexity). Seven cases involved reoperation for tumor recurrence. RESULTS In all 7 of the cases requiring reoperation, a new arachnoid-like surface layer was formed without any dural adhesions. The newly formed layer allowed for easy and simple dissection and mobilization of surface vessels while avoiding any trauma to the cortex. CONCLUSIONS Amniotic sac implants have a promising role in preventing most surgical brain adhesions associated with recurrent glioma surgery, reducing the risks of cortical vessel and tissue injury.

Rapid M1 Hemoclips Arteriotomy Repair After Emergency Coil Embolectomy

BACKGROUND The vascular closure staple clips have been studied in animal models and shown to have comparable results with sutured repair when it comes to the healing process, degree of vessel narrowing, and risk of thrombosis. However, they are clearly superior when the speed of application is taken into account, and they were clinically used in many vascular repair processes. Nevertheless, their usefulness in intracranial vascular surgery has not been described. OBJECTIVE To describe the usefulness of hemoclips in fast and efficient repair of medium-sized and large intracranial vessels. METHODS Two female patients diagnosed with giant symptomatic cavernous sinus aneurysms were undergoing elective endovascular procedures that were complicated by the dislodgement of coils into the M1 segment of the middle cerebral artery. Both patients were treated performing M1 arteriotomies and coil embolectomy. To avoid prolonged temporary occlusion in the M1 perforators territory, the arteriotomies were repaired using microhemoclips in less than 10 min with re-establishment of flow. RESULTS In both patients, flow was re-established in the M1 segments. In 1 patient, the coils extended to the temporal M2 causing intimal injury and leading to diminished flow. M1 segments in both patients were patent on later angiographic studies. CONCLUSION We describe the advantage of emergent cerebrovascular arteriotomy and embolectomy in a rapid repair process that helped avoid massive ischemic injury. We believe this technique should be added to the armamentarium of neurosurgical cerebrovascular options.

Pseudoaneurysm Surgery Simulation Using the “Live Cadaver” Model for Neurosurgical Education

Reduced number of working hours for residents and the trend toward minimal or even noninvasive treatment of cerebral aneurysms have resulted in residents’ decreased exposure to live surgery in the operating room. This decrease becomes increasingly relevant when surgeons encounter complications, especially vascular injuries and intraoperative rupture of aneurysms, after completion of their training, neurosurgery residents will face complicated cases and intraoperative aneurysmal rupture in their practice while they are on their own, and to develop competency in managing cerebral aneurysms, laboratory training will be the compensation mechanism to cover the decreased hands-on experience in the OR. In this chapter we will describe a more realistic aneurysm model, which allows repetitive training under lifelike conditions for residents and other trainees to practice surgical clipping of cerebral aneurysms.

The Role of the NREF Endovascular and Cerebrovascular Courses in Neurosurgical Residency and Fellowship Training and Future Directions

In 1980, the National Education and Research Foundation was established by the American Association of Neurological Surgeons. One of its primary goals is to provide education to Neurosurgeons at all stages of their career. In recent years, technological advances, increased public demand for safety, and duty hour restrictions have decreased the opportunity for neurosurgical residents to gain exposure to complex cerebrovascular surgeries. Surgical simulation and cadaver dissections offer physicians the opportunity to learn complex anatomy and techniques without harming patients. Although simulation has been widely used in many nonmedical fields, neurosurgical simulation is still in its infancy. In this chapter, we review the history and role of the vascular education courses in training neurosurgical residents and neurointerventional fellows.