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Objective: The aim of this study was to describe quantitatively the properties of the posterolateral approaches and their combination., Methods: Six silicone-injected cadaveric heads were dissected bilaterally. Quantitative data were generated with the Optotrak 3020 system (Northern Digital, Waterloo, Canada) and Surgiscope (Elekta Instruments, Inc., Atlanta, GA), including key anatomic points on the skull base and brainstem. All parameters were measured after the basic retrosigmoid craniectomy and then after combination with a basic far-lateral extension. The clinical results of 20 patients who underwent a combined retrosigmoid and far-lateral approach were reviewed., Results: The change in accessibility to the lower clivus was greatest after the far-lateral extension (mean change, 43.62 +/- 10.98 mm2; P = .001). Accessibility to the constant landmarks, Meckel's cave, internal auditory meatus, and jugular foramen did not change significantly between the 2 approaches (P > .05). The greatest change in accessibility to soft tissue between the 2 approaches was to the lower brainstem (mean change, 33.88 +/- 5.25 mm2; P = .0001). Total removal was achieved in 75% of the cases. The average postoperative Glasgow Outcome Scale score of patients who underwent the combined retrosigmoid and far-lateral approach improved significantly, compared with the preoperative scores., Conclusion: The combination of the far-lateral and simple retrosigmoid approaches significantly increases the petroclival working area and access to the cranial nerves. However, risk of injury to neurovascular structures and time needed to extend the craniotomy must be weighed against the increased working area and angles of attack.

Objective: Lesions in the thalamomesencephalic junction can be reached via an anterolateral approach, interhemispheric approach, transcortical (parieto-occipital lobule) approach, subtemporal approach, supracerebellar approaches, or transsylvian-insular approach. We now describe a new approach, a transanterior perforating substance approach, to this territory., Methods: A 33-year-old man with progressive right arm tremors, mild hemiparesis, and a cavernous malformation of the thalamomesencephalic junction was followed for 5 years. Because of clinical progression, he underwent a left orbitozygomatic approach to the cavernous malformation, which could not be accessed because of a high-riding basilar artery. Hence, a new transsylvian corridor of exposure was developed using frameless neuronavigation. The trajectory, which was dorsal to M1, led through the perforating branches of M1. Care was taken to avoid violating any arterial perforators. To reach the lesion, a small opening into the brain was created near the optic tract., Results: The cavernous malformation was resected totally. Postoperatively, the patient's tremors were cured. No visual deficits were encountered. Imaging showed a small ischemic stroke in the basal ganglia likely related to manipulation of a perforator. Initially, his hemiparesis worsened, but it improved significantly within 10 months with only a moderate decrease in strength., Conclusion: The transanterior perforating substance approach effectively allowed access to the thalamomesencephalic junction and was associated with significant morbidity. However, the safety of the approach needs further validation. Neuronavigation is indicated to choose the most direct trajectory through the M1 perforators. Tractography may help protect the optic tract.

Objective: We retrospectively reviewed our experience treating third ventricular colloid cysts to compare the efficacy of endoscopic and transcallosal approaches., Methods: Between September 1994 and March 2004, 55 patients underwent third ventricular colloid cyst resection. The transcallosal approach was used in 27 patients; the endoscopic approach was used in 28 patients. Age, sex, cyst diameter, and presence of hydrocephalus were similar between the two groups., Results: The operating time and hospital stay were significantly longer in the transcallosal craniotomy group compared with the endoscopic group. Both approaches led to reoperations in three patients. The endoscopic group had two subsequent craniotomies for residual cysts and one repeat endoscopic procedure because of equipment malfunction. The transcallosal craniotomy group had two reoperations for fractured drainage catheters and one operation for epidural hematoma evacuation. The transcallosal craniotomy group had a higher rate of patients requiring a ventriculoperitoneal shunt (five versus two) and a higher infection rate (five versus none). Intermediate follow-up demonstrated more small residual cysts in the endoscopic group than in the transcallosal craniotomy group (seven versus one). Overall neurological outcomes, however, were similar in the two groups., Conclusion: Compared with transcallosal craniotomy, neuroendoscopy is a safe and effective approach for removal of colloid cysts in the third ventricle. The endoscope can be considered a first-line treatment for these lesions, with the understanding that a small number of these patients may need an open craniotomy to remove residual cysts.

Objective: We explored relevant regional microanatomy as it relates to the challenging anterior interforniceal (AIF) approach for removing hypothalamic hamartomas., Methods: Five silicone-injected cadaveric heads were dissected by use of frameless stereotactic navigation to reveal microanatomy and extent of exposure through the transcallosal AIF approach. Distances between trajectories to the coronal suture and the genu of the corpus callosum (CC) and between the posterior border of the anterior commissure to the lower end of the rostrum of the CC and posterior border of the foramen of Monro were measured., Results: The AIF approach provided adequate access to the anterior third ventricle and related structures (i.e., hypothalamus, infundibular recess, and mamillary bodies) through the corridor bounded by the anterior commissure anteriorly and the choroid plexus at the foramen of Monro posteriorly. The mean distances from the posterior trajectory to the coronal suture and the genu of the CC were 44.8 mm (range, 43.8-46.2 mm) and 14.88 mm (14.1-15.7 mm), respectively. The mean distance from the anterior trajectory posterior to the coronal suture was 4.66 mm (0-8.9 mm), and 32.6 mm (30.5-33.9 mm) to the genu of the CC. The mean length of callosotomy was 17.52 mm (16.2-19.1 mm). The mean distance between the posterior border of the anterior commissure and the lower end of the rostrum of the CC was 5.22 mm (4.6-5.6 mm), and 10.52 mm (9.7-11.5 mm) to the posterior border of the foramen of Monro., Conclusion: The technically safe AIF approach permitted limited interforniceal splitting, no major deep vein manipulation, and adequate visualization of the hypothalamus, infundibular recess, and mamillary bodies.

Objective: Invasion of the brain and/or dura is a known negative prognostic factor for patients undergoing craniofacial resection for cranial base malignancy. However, an evaluation of factors that may affect prognosis in this patient subgroup has not been undertaken., Methods: Between 1993 and 2003, 212 patients underwent craniofacial resection for primary malignancy of the cranial base at the University of Texas M.D. Anderson Cancer Center. Twenty-eight patients (eight women, 20 men; median age, 52 yr; age range, 26-76 yr) had evidence of transdural spread (subdural tumor or brain invasion) of malignancy. These patients were identified and a retrospective review of prospectively collected data was undertaken., Results: Subdural tumors were found in 16 of these patients, and brain invasion was detected in 12. Gross total resections were achieved in 22 patients: 13 with microscopically negative margins, eight with positive margins, and one with unspecified margins. Surgical complications occurred in six patients. There was no surgical mortality. The 5-year actuarial overall survival (OS) was 58%. Eleven patients had no evidence of disease, 11 died of disease, and six were alive with disease at the end of the follow-up period. The median actuarial progression-free survival (PFS) was 38 months (95% confidence interval, 4-72 mo). Gross total resection with negative margins was the key positive predictor of OS and PFS. Brain invasion was a negative predictor of survival (significant for PFS; trend only for OS). There was a trend for shorter OS and PFS in patients with high-grade tumors., Conclusion: Overall OS and PFS in highly selected patients with transdural invasion of cranial base malignancy is similar to what has been historically reported for patients without such invasion. The most important variables positively affecting OS and PFS seem to be the ability to achieve a microscopically margins-negative resection followed by absence of brain invasion. Performing this resection in a piecemeal fashion does not seem to affect survival outcomes.

Objective: We retrospectively reviewed our experience treating third ventricular colloid cysts to compare the efficacy of endoscopic and transcallosal approaches., Methods: Between September 1994 and March 2004, 55 patients underwent third ventricular colloid cyst resection. The transcallosal approach was used in 27 patients; the endoscopic approach was used in 28 patients. Age, sex, cyst diameter, and presence of hydrocephalus were similar between the two groups., Results: The operating time and hospital stay were significantly longer in the transcallosal craniotomy group compared with the endoscopic group. Both approaches led to reoperations in three patients. The endoscopic group had two subsequent craniotomies for residual cysts and one repeat endoscopic procedure because of equipment malfunction. The transcallosal craniotomy group had two reoperations for fractured drainage catheters and one operation for epidural hematoma evacuation. The transcallosal craniotomy group had a higher rate of patients requiring a ventriculoperitoneal shunt (five versus two) and a higher infection rate (five versus none). Intermediate follow-up demonstrated more small residual cysts in the endoscopic group than in the transcallosal craniotomy group (seven versus one). Overall neurological outcomes, however, were similar in the two groups., Conclusion: Compared with transcallosal craniotomy, neuroendoscopy is a safe and effective approach for removal of colloid cysts in the third ventricle. The endoscope can be considered a first-line treatment for these lesions, with the understanding that a small number of these patients may need an open craniotomy to remove residual cysts.

Objective: We present a novel variable aspiration tissue resector for use with neuroendoscopy., Methods: Two patients, 4 and 14 years old, respectively, presented with intractable gelastic seizures refractory to maximal medical therapies. Magnetic resonance imaging showed mass lesions of the third ventricle consistent with hypothalamic hamartoma., Results: The patients underwent magnetic resonance imaging wand-guided endoscopic resection of the tumor with the Suros novel variable aspiration tissue resector. There were no device-associated complications or adverse events. The hamartoma was disconnected in one patient, and gross total resection was achieved in the other., Conclusion: Endoscopy for tumor resection is still frustrated by the lack of surgical tools, such as ultrasonic aspirators, comparable with those available for use during open procedures. The variable-aspiration tissue resector reported here can be used to resect tumor tissue safely. These two cases demonstrate that gross total resection of small hypothalamic hamartomas is feasible with minimal morbidity through an endoscopic approach.

Objective and Importance: A 31-year-old woman presented with an avulsion fracture of the foramen magnum via bilateral occipital condyles with extension through the inferior aspect of the clivus., Clinical Presentation: The patient had no neurological deficits and was initially immobilized in a halo brace., Intervention: To preserve rotational motion at C1-C2, we performed an occiput-to-C1 fusion with bilateral C1 lateral mass screws attached with rods to occipital keel screws. Postoperatively, the patient remained neurologically intact. Three-month follow-up imaging revealed no abnormal motion. Follow-up computed tomographic scan showed an intact construct and bony fusion., Conclusion: This rare injury, a bony variant of occipitoatlantal dislocation, was successfully treated with a unique occiput-to-C1 fusion.

Objective: Olfaction is often sacrificed to gain access to the cranial base in anterior craniofacial surgery. We describe the long-term results of olfactory function in patients who underwent anterior craniofacial surgery and a cribriform plate osteotomy to preserve olfaction., Methods: Between 1992 and 2004, 28 patients underwent 29 cribriform plate osteotomies in an attempt to preserve olfaction during anterior craniofacial surgery performed through modified extended transbasal approaches. Patients' charts and office notes were reviewed retrospectively. Formal olfactory testing was available in 5 patients, but most data were based on patients' subjective reports of olfaction. Olfactory preservation was defined by the subjective ability to detect fumes such as coffee, chocolate, roses, and orange juice regardless of the intensity of the sensation. Follow-up was based on phone calls to patients., Results: Four patients were lost to follow-up and excluded. Therefore, follow-up was available in 24 patients after 25 procedures. On the basis of patients' subjective reports, olfaction was spared in 22 patients after 23 procedures (92%) and was confirmed objectively in the five patients formally tested. After surgery, only two patients were anosmic., Conclusion: Olfaction can be preserved in selected patients undergoing anterior craniofacial surgery. At least 1 cm of nasal mucosa should remain attached to the cribriform plate, which can be achieved by including the nasal bone in the osteotomy of the orbital bar. A medial orbital canthopexy is therefore necessary after these procedures.

Objective: We explored relevant regional microanatomy as it relates to the challenging anterior interforniceal (AIF) approach for removing hypothalamic hamartomas., Methods: Five silicone-injected cadaveric heads were dissected by use of frameless stereotactic navigation to reveal microanatomy and extent of exposure through the transcallosal AIF approach. Distances between trajectories to the coronal suture and the genu of the corpus callosum (CC) and between the posterior border of the anterior commissure to the lower end of the rostrum of the CC and posterior border of the foramen of Monro were measured., Results: The AIF approach provided adequate access to the anterior third ventricle and related structures (i.e., hypothalamus, infundibular recess, and mamillary bodies) through the corridor bounded by the anterior commissure anteriorly and the choroid plexus at the foramen of Monro posteriorly. The mean distances from the posterior trajectory to the coronal suture and the genu of the CC were 44.8 mm (range, 43.8-46.2 mm) and 14.88 mm (14.1-15.7 mm), respectively. The mean distance from the anterior trajectory posterior to the coronal suture was 4.66 mm (0-8.9 mm), and 32.6 mm (30.5-33.9 mm) to the genu of the CC. The mean length of callosotomy was 17.52 mm (16.2-19.1 mm). The mean distance between the posterior border of the anterior commissure and the lower end of the rostrum of the CC was 5.22 mm (4.6-5.6 mm), and 10.52 mm (9.7-11.5 mm) to the posterior border of the foramen of Monro., Conclusion: The technically safe AIF approach permitted limited interforniceal splitting, no major deep vein manipulation, and adequate visualization of the hypothalamus, infundibular recess, and mamillary bodies.

Objective and Importance: We describe a patient with a cavernous malformation within the trigeminal nerve at the nerve root entry zone who presented with trigeminal neuralgia., Clinical Presentation: A 52-year-old woman sought treatment after experiencing dizziness and lancinating left facial pain for almost a year. Neurological examination revealed diminished sensation in the distribution of the trigeminal nerve on the left. Magnetic resonance imaging demonstrated a minimally enhancing lesion affecting the trigeminal nerve., Intervention: The patient underwent a retrosigmoid craniotomy. At the nerve root entry zone, the trigeminal nerve was edematous with hemosiderin staining. The lesion, which was resected with microsurgical technique, had the appearance of a cavernous malformation on gross and histological examination. The patient's pain improved significantly after resection., Conclusion: Cavernous malformations can afflict the trigeminal nerve and cause trigeminal neuralgia. Microsurgical excision can be performed safely and is associated with improvement in symptoms.

Objective: A single-stage combined craniofacial-transfacial approach that exposes the midline cranial base without visible facial incisions is described., Methods: Between 1992 and 1998, eight patients underwent surgery for five different anterior cranial base pathological findings: four angiofibromas, one mesenchymal chondrosarcoma, one esthesioneuroblastoma, one odontogenic myxoma, and one encephalocele. In all cases, the surgical exposure consisted of a bicoronal scalp incision with a bifrontal craniotomy and fronto-orbitonasal osteotomy, and then a sublabial incision for transmaxillary exposure., Results: Gross total resection was achieved in five cases. The encephalocele was resected with complete reconstruction of the bony defect. Seven patients developed complications, primarily wound infections, cerebrospinal fluid leaks, and anemia. Postoperative Karnofsky Performance Scale scores ranged between 80 and 100 (mean, 92.5). Long-term follow-up information (mean, 56 mo; median, 59.5 mo; range, 5-108 mo) was available for all patients., Conclusion: Large anterior cranial base lesions can be resected and excellent cosmetic outcomes can be achieved with a single-stage combined transfacial-craniofacial approach that exposes the entire midline cranial base and requires no facial incisions.

Objective and Importance: Aneurysms involving the distal lenticulostriate artery branches are a rare cause of spontaneous intracerebral hemorrhage. We report a case of ruptured lenticulostriate aneurysm in an otherwise healthy patient and review the literature on this topic., Clinical Presentation: Computed tomography showed a right basal ganglia hemorrhage in a 44-year-old Native American woman with acute left hemiparesis. Cerebral angiography showed a 2-mm aneurysm in a distal lenticulostriate artery branch., Technique: A pterional craniotomy was performed on a delayed basis using computed tomographic angiography and frameless stereotactic guidance. The basal ganglia hematoma was evacuated, and the aneurysm was identified and clipped using microsurgical technique. Because the base of the aneurysm involved a portion of the parent vessel wall, it was wrapped with cotton and reinforced with cyanoacrylate glue. The patient did well after surgery and was discharged to home with outpatient rehabilitation on the third postoperative day., Conclusion: Although intraparenchymal hemorrhages are fairly common, the underlying vascular abnormality is rarely identified. Most are related to hypertensive vascular degeneration, rupture of a Charcot-Bouchard aneurysm, or both. When intracerebral hemorrhage occurs in young patients, however, aggressive investigation is warranted to rule out a structural vascular abnormality.