A. Samy Youssef

Paradoxical Trends in the Management of Unruptured Cerebral Aneurysms in the United States: Analysis of Nationwide Database Over a 10-Year Period

Background and Purpose— The objective of this study was to characterize demographics, treatments, and outcomes in the management of unruptured cerebral aneurysms in the United States using a national healthcare database. Methods— Clinical data were derived from the Nationwide Inpatient Sample for the years 1997 through 2006. Patients with unruptured cerebral aneurysms were identified using the appropriate International Classification of Diseases, 9th Revision code (437.3). Hospitalizations, length of stay, hospital charges, discharge pattern, age and gender distribution, and nature of intervention were analyzed. A Bureau of Labor statistics tool was used to adjust hospital and national charges for inflation. Population-adjusted rates were calculated using population estimates generated by the US Census Bureau. Results— Over 100 000 records were retrieved for analysis. During the time period studied, there was a 75% increase in the number of hospitalizations associated with unruptured cerebral aneurysms. Inflation adjusted hospital charges increased by 60%, whereas the total national bill increased by 200%. Overall, length of stay decreased by 37% and in-hospital mortality rates decreased by 54%. The increasing number of hospitalizations and total national charges related to inpatient treatment of unruptured aneurysms were significantly associated with endovascular treatment rather than surgical clipping. Conclusions— Despite recent studies suggesting a low risk of rupture of incidentally diagnosed cerebral aneurysms, data from this study suggest an increasing trend of treatment for this entity in the United States. Furthermore, endovascular intervention is now the major driving force behind the increasing overall national charges. Given the current healthcare climate, the impact of these trends warrants discussion and debate.

Transcranial surgery for pituitary adenomas.

ALTHOUGH THE TRANSSPHENOIDAL approach is the preferred approach to the vast majority of pituitary tumors with or without suprasellar extension, the transcranial approach remains a vital part of the neurosurgical armamentarium for 1 to 4% of these tumors. The transcranial approach is effective when resection becomes necessary for a portion of a pituitary macroadenoma that is judged to be inaccessible from the transsphenoidal route because of isolation by a narrow waist at the diaphragma sellae, containment within the cavernous sinus lateral to the carotid artery, projection anteriorly onto the planum sphenoidale, or projection laterally into the middle fossa. The application of a transcranial approach in these circumstances may still be mitigated by response to prolactin inhibition of prolactinomas, the frequent lack of necessity to remove asymptomatic nonsecretory adenomas from the cavernous sinus, and the lack of evidence that sustained chemical cures can be reliably achieved by removal of secretory adenomas (adrenocorticotropic hormone, growth hormone) from the cavernous sinus. Cranial base surgical techniques have refined the surgical approach to pituitary adenomas but have had less effect on actual surgical indications than anticipated. Because application of the transcranial approach to pituitary adenomas is and should be rare in clinical practice, it is useful to standardize the technique to a default mode with which the surgical team is most experienced and, therefore, most comfortable. Our default mode for transcranial pituitary surgery is the frontotemporal-orbitozygomatic approach.

Intraoperative neurophysiological monitoring in vestibular schwannoma surgery: advances and clinical implications

OBJECT Intraoperative neurophysiological monitoring has become an integral part of vestibular schwannoma surgery. The aim of this article was to review the different techniques of intraoperative neurophysiological monitoring in vestibular schwannoma surgery, identify the clinical impact of certain pathognomonic patterns on postoperative outcomes of facial nerve function and hearing preservation, and highlight the role of postoperative medications in improving delayed cranial nerve dysfunction in the different reported series. METHODS The authors performed a review of the literature regarding intraoperative monitoring in acoustic/vestibular schwannoma surgery. The different clinical series representing different monitoring techniques were reviewed. All the data from clinical series were analyzed in a comprehensive and comparative model. RESULTS Intraoperative brainstem auditory evoked potential monitoring, direct cochlear nerve action potential monitoring, and facial nerve electromyography are the main tools used to assess the functional integrity of an anatomically intact cranial nerve. The identification of pathognomonic brainstem auditory evoked potential and electromyography patterns has been correlated with postoperative functional outcome. Recently, perioperative administration of intravenous hydroxyethyl starch and nimodipine as vasoactive and neuroprotective agents was shown to improve vestibular schwannoma functional outcome in few reported studies. CONCLUSIONS Recent advances in electrophysiological technology have considerably contributed to improvement in functional outcome of vestibular neuroma surgery in terms of hearing preservation and facial nerve paresis. Perioperative intravenous nimodipine and hydroxyethyl starch may be valuable additions to surgery.

Long-term outcome of vagus nerve stimulation therapy after failed epilepsy surgery

OBJECTIVE Adequate control of intractable epilepsy continues to be a challenge. Little is known about the role of VNS therapy in intractable epilepsy in patients who failed to respond to surgical management. The objective of the present study is to determine the efficacy of vagus nerve stimulation therapy in patients with intractable epilepsy who have failed surgical and medical therapy. METHODS All the patients who had persistent seizures after cranial surgery who subsequently underwent vagus nerve stimulator (VNS) placement at our institution from 1998 to 2008 were included in the study. Thirty-seven consecutive patients were enrolled and followed for the outcome measures of seizure burden, anti-epileptic drug (AED) burden and quality of life (QoL). Minimum follow-up was 18 months. RESULTS Overall, 24 (64.9%), 9 (24.3%), 4 (10.8%) patients reported less than 30%, between 30% and 60% and greater than 60% reduction in seizure frequency after VNS placement, respectively at a mean of 5 years follow-up period. Post-VNS anti-epileptic requirement exhibited a decreasing trend. 17 patients (45.9%) report an improvement in QoL (better or much better). CONCLUSION VNS therapy in patients who have failed medical and surgical therapies only provides marginal improvement in seizure control but has greater likelihood to improve subjective QoL issues. In addition, VNS has the potential to reduce AED burden without adversely impacting seizure management. Given the low surgical risk of VNS placement, vagus nerve stimulation as a therapeutic modality should be individualized to achieve best clinical response and fewest side effects.

Modifications of the transoral approach to the craniovertebral junction: anatomic study and clinical correlations.

OBJECTIVE This study was designed to more precisely characterize the changes in exposure achieved by modifying the standard transoral approach by sequential mandibulotomy and mandibuloglossotomy with or without palatotomy. METHODS A series of cadaveric dissections was performed and the operative distance and angle of exposure in both axial and sagittal planes was evaluated for each approach, with and without palatotomy. Intraoperative measurements were made in patients undergoing transoral approaches to assess the validity of the anatomic model. The use of this model was then assessed by a retrospective analysis of a group of 19 patients operated on through transoral approaches between 1991 and 2006. RESULTS The simple transoral approach exposed the region from the lower third of the clivus to the middle of the C2 vertebral body at an operative distance of 12.9 ± 1.0 cm from the dura. The axial and sagittal angles of exposure were 39.4 ± 3.5 degrees and 36.8 ± 3.5 degrees, respectively. Mandibulotomy significantly increased the sagittal exposure to 59.0 ± 1.0 degrees (P < 0.001), exposing the area from the midclivus to the C2–C3 interspace while simultaneously increasing the axial angle of exposure to 51.9 ± 7.4 degrees (P < 0.01) and decreasing the operative distance to the dura to 10.7 ± 1.7 cm (P < 0.05). Mandibuloglossotomy augmented sagittal exposure to 85.3 ± 0.3 degrees (P < 0.001), revealing the region between the upper one-third of the clivus and the C4–C5 interspace (P < 0.001) while decreasing the operative distance to the dura to 8.7 ± 0.3 cm (P < 0.05). Palatotomy significantly increased the rostral exposure achieved by each approach by 8.5 to 12.3 degrees (P < 0.01) without altering caudal or axial exposure or the operative distance. CONCLUSION The cadaveric data correlated well with intraoperative measurements and the need for modifications of the transoral approach in 15 of the 16 adult patients (93.8%). Pediatric patients, patients with limited mouth opening, elevated craniovertebral junctions, and particularly deep lesions required more extensive exposure. This analysis may be useful for determining the optimal approach for patients undergoing transoral surgery.

Craniocervical fixation with occipital condyle screws: Biomechanical analysis of a novel technique

Study Design. A human cadaveric biomechanical study comparing craniocervical fixation techniques. Objective. To quantitatively compare the biomechanical stability of a new technique for occipitocervical fixation using the occipital condyles with an established method for craniocervical spine fusion. Summary of Background Data. Stabilization of the occipitocervical junction remains a challenge. The occiput does not easily accommodate instrumentation because of access and spatial constraints. In fact, the area available for the implant fixation is limited and can be restricted further when a suboccipital craniectomy has been performed, posing a challenge to current fixation techniques. Occipital screws are also associated with the potential for intracranial complications. Methods. Six fresh frozen cadaveric specimens occiput-C4 were tested intact, after destabilization and after fixation as follows: (1) occipital plate with C1 lateral mass screws and C2 pars screws and (2) occipital condyle screws with C1 lateral mass screws and C2 pars screws. Specimens were loaded in a custom spine testing apparatus and subjected to the following tests, all performed under 50-N unconstrained axial preload: flexion, extension, lateral bending, and axial rotation at 1.5 Nm. The constructs were statistically compared with a one-way analysis of variance and compared with the intact condition. Results. Motions were reduced by ∼80% compared with the intact condition for both configurations under all motions. There were no statistically significant differences in the range of motion (ROM) between the 2 instrumentation conditions. The mean values indicated decreased ROM with the novel occipital condyle screw construct in comparison with the standard occipital plate and rod system. Conclusion. Craniocervical stabilization using occipital condyle screws as the sole cephalad fixation point is biomechanically equivalent with regard to the modes tested (ROM and stiffness) to the standard occipital plate construct.

OCCIPITAL CERVICAL STABILIZATION USING OCCIPITAL CONDYLES FOR CRANIAL FIXATION: TECHNICAL CASE REPORT

OBJECTIVEPresentation of a successful case of craniocervical stabilization involving a novel surgical technique using the occipital condyles as the sole cranial fixation points. CLINICAL PRESENTATIONA 22-year-old man presented in a delayed fashion with neck pain after a motor vehicle accident. Evaluation revealed a type 2 odontoid fracture with pseudarthrosis and displacement of the dens superiorly and cranial settling of the dens. INTERVENTIONThe patient underwent posterior occipitocervical fixation with a polyaxial screw rod construct using the occipital condyle, C1 lateral mass, and C2 pars articularis for fixation. The patient had no immediate postoperative deficits. At the time of the 12-month follow-up examination, the patient was neurologically intact with a solid occipitocervical fusion. CONCLUSIONCraniocervical stabilization using occipital condyle screws as the sole cephalad fixation points is a feasible option and can be used safely without neurovascular complication in the treatment of craniocervical instability.

Extended transoral approaches: surgical technique and analysis.

BACKGROUNDThe transoral approach provides the most direct exposure to extradural lesions of the ventral craniovertebral junction. Lesions that extend beyond the exposure provided by the standard transoral approach require an extended transoral modification. The exposure can be expanded in the sagittal and axial planes by adding mandibulotomy, mandibuloglossotomy, palatotomy, and transmaxillary approaches to the standard transoral approach. Extended transoral approaches increase the surgical complexity and the risk of cosmetic and functional complications. Until recently, selection of an extended approach has been arbitrary and dependent on the surgeons familiarity with the surgical approach. OBJECTIVEWe review the literature of extended transoral approaches and analyze the different modifications in terms of the technical aspects, added exposure, and complications. METHODSClassic approaches and recently published morphometric studies that objectively document the gain in exposure provided by several modifications were analyzed and tabulated to outline the limits of exposure and risk of complications associated with the various modifications. RESULTSTransmaxillary approaches expand the exposure to include the sphenoid sinus and upper lateral clivus. To expand the exposure more inferiorly to C4–C5, mandibulotomy or mandibuloglossotomy can be applied. Mandibuloglossotomy increases the rostral exposure as well to the upper third of the clivus. Palatotomy increases rostral exposure without requiring a facial incision or perioperative tracheostomy, but is associated with a significant risk of velopharyngeal insufficiency. CONCLUSIONSurgical decisions can be based on comprehensive preoperative evaluation of anatomy, pathology, and radiographic studies to maximize exposure while minimizing complications.BACKGROUND The transoral approach provides the most direct exposure to extradural lesions of the ventral craniovertebral junction. Lesions that extend beyond the exposure provided by the standard transoral approach require an extended transoral modification. The exposure can be expanded in the sagittal and axial planes by adding mandibulotomy, mandibuloglossotomy, palatotomy, and transmaxillary approaches to the standard transoral approach. Extended transoral approaches increase the surgical complexity and the risk of cosmetic and functional complications. Until recently, selection of an extended approach has been arbitrary and dependent on the surgeons familiarity with the surgical approach. OBJECTIVE We review the literature of extended transoral approaches and analyze the different modifications in terms of the technical aspects, added exposure, and complications. METHODS Classic approaches and recently published morphometric studies that objectively document the gain in exposure provided by several modifications were analyzed and tabulated to outline the limits of exposure and risk of complications associated with the various modifications. RESULTS Transmaxillary approaches expand the exposure to include the sphenoid sinus and upper lateral clivus. To expand the exposure more inferiorly to C4-C5, mandibulotomy or mandibuloglossotomy can be applied. Mandibuloglossotomy increases the rostral exposure as well to the upper third of the clivus. Palatotomy increases rostral exposure without requiring a facial incision or perioperative tracheostomy, but is associated with a significant risk of velopharyngeal insufficiency. CONCLUSION Surgical decisions can be based on comprehensive preoperative evaluation of anatomy, pathology, and radiographic studies to maximize exposure while minimizing complications.

Field of view comparison between two-dimensional and three-dimensional endoscopy

Relative to microscopic transnasal surgery, endoscopic surgery provides improved visualization with an increased field of view. Advances such as high‐definition (HD) and three‐dimensional (3D) endoscopy have been introduced and clearly improve visualization. However, do both technologies maintain an increased field of view? We hypothesize that the field of view of 3D endoscopy is restricted relative to two‐dimensional (2D) HD endoscopy.

Sudden blindness as a complication of percutaneous trigeminal procedures: mechanism analysis and prevention

The authors describe the case of a 76-year-old man in whom reversible sudden blindness developed after a percutaneous balloon compression rhizotomy for trigeminal neuralgia. His eye became tense and swollen with intraocular pressures of 66 mm Hg. Acetazolamide was administered, and visual acuity (20/50) returned within several months. Despite correct needle placement, the intraocular pressure rose acutely because of transient occlusion of the orbital venous drainage through the cavernous sinus; this was reversed with aggressive medical treatment. In cadaveric studies (dried skull and formalin-fixed head), the authors studied the mechanism of optic nerve penetration. Their findings showed that excessive cranial angulation of the needle with penetration of the inferior orbital fissure can directly traumatize the optic nerve in the orbital apex. Direct trauma to the optic nerve can therefore be prevented by early and repeated confirmation of the needle trajectory with lateral fluoroscopy before penetration of the foramen ovale.