Faculty Bibliography

BACKGROUND:Cavernous sinus (CS) tumors often are considered inoperable. We present our experience with endoscopic endonasal surgery (EES) and compare the outcomes for different tumor. METHODS:EES (medial or lateral approach) was used in 234 patients with CS tumors. The cohort included 175 (75%) pituitary adenomas and 59 (25%) nonadenomatous lesions. RESULTS:Presenting symptoms were significantly different between the 2 groups, with cranial neuropathies occurring mainly in nonadenomas (P < 0.0001). The overall gross total tumor resection rate from the CS was 37.3% (37.1% in adenomas, 38.1% in non-adenomas). In total, preexisting cranial nerve (CN) dysfunction improved in 56.4% of the patients. After treatment completion (including radiation of residual tumor), 83.3% of acromegalic patients, 50% of prolactinomas and 33.3% of Cushing's disease, were in remission. Visual loss improved in 86.8% of adenomas and in 70.8% of nonadenomas. Intracavernous CN palsies improved in 77.3% of adenomas and 42.4% of nonadenomas. New permanent CN palsies occurred in 7 nonadenomas, which is significantly greater than in adenomas (P = 0.007). The leak rate of cerebrospinal fluid was 6.3% for adenomas and 11.9% for nonadenomas. Four patients suffered an internal carotid artery injury with no neurologic sequelae in 3 cases and 1 death (0.4%). CONCLUSIONS:EES provides an easily accessible midline corridor to the CS with equivalent or superior results to transcranial approaches in the management of select tumors. Symptomatology due to CS invasion is more likely to improve in pituitary adenomas and the rate of surgical complications is greater in nonadenomas. Using a team approach, the overall mortality due to vascular injury is low.

OBJECTIVE:The purpose of this study was to analyze the outcomes and complications of the endoscopic endonasal approach (EEA) performed on patients with Cushing disease at our Pituitary Center during the past 11 years. METHODS:testing and Student's t-test. RESULTS:Remission was achieved in 39 patients (79.6%) at initial evaluation within 2 weeks of surgery. At last follow-up, remission persisted in 70% of 50 patients with EEA alone (mean follow-up time, 37.5 ± 4.6 months; median, 26.2 months; range, 2.5-155.0 months). At last follow-up, remission rates were 80% among magnetic resonance imaging-negative adenomas, 70.6% among noninvasive or minimally invasive adenomas (Knosp 0, 1, 2), and 50% among invasive adenomas (Knosp 3, 4). There were no statistical differences in the remission rates among these categories (P = 0.444). Women had higher proportions of initial remission than men (P = 0.033) and patients who had no initial remission were older (P = 0.046). Higher preoperative normalized adrenocroticotropic hormone level was associated with a greater degree of invasiveness (P = 0.021). However, there was no association between preoperative normalized urine-free cortisol levels and degree of invasiveness (P = 0.582). Complications included panhypopituitarism (n = 3), hypothyroidism (n = 3), growth hormone deficiency (n = 1), hypogonadism (n = 1), postoperative cerebrospinal fluid leak (n = 2), and transient diabetes insipidus (n = 4). CONCLUSIONS:The EEA for Cushing disease resulted in remission and complication rates comparable with previous analyses of EEA, as well as microsurgical series. Preoperative adrenocorticotropic hormone levels were associated with invasiveness.

OBJECTIVE:Transpetrosal approaches for the treatment of petroclival meningiomas are often associated with substantial morbidity and long recovery. With the goal of early clinical improvement, we have used less invasive surgical approaches for petroclival meningiomas. METHODS:We retrospectively reviewed 32 patients with petroclival meningiomas. Eleven patients (34.4%) were managed with lateral approaches (retrosigmoid or far lateral approach), 17 (53.1%) with anterior midline approaches (endoscopic endonasal approach [EEA]), and 4 (12.5%) with a combination. RESULTS:The average Karnofsky Performance Score (KPS) at presentation was 73.8. The average postoperative KPS improved to 87.9 (P < 0.001) during short-term follow-up of 14 months (range, 1-42) and was significantly higher in primary tumors (P = 0.013), tumors <4 cm (P = 0.039), and tumors without vascular encasement (P = 0.002) but remained significant regardless of age, tumor size, or vascular encasement. The greatest benefit occurred with primary tumors, in young patients and in those who underwent nontotal resection (P < 0.001). EEA had a significantly greater potential for improved KPS (P = 0.002). Gross (n = 6) or near total (n = 9) resection was achieved in 15 of 32 cases (47%). Complications included new cranial nerve palsies affecting mainly the abducens nerve (18.7%). New lower cranial nerve palsies occurred in only 1 case (3.1%). Other complications included postoperative hydrocephalus (15.6%) and cerebrospinal fluid leak (28.1%). One patient died in the perioperative period (3.1%). CONCLUSIONS:In the short-term, less aggressive cranial base approaches, including retrosigmoid exposures and the recently introduced EEA, are effective alternatives to transpetrosal approaches for debulking petroclival meningiomas with significant early clinical improvement and limited major surgical complications.

BACKGROUND:Classically used for treatment of orbital lesions, the lateral orbitotomy with cantholysis can be combined with a temporal craniectomy for lesions involving the middle cranial fossa. OBJECTIVE:To present a single-center experience with the lateral orbitotomy approach for lesions involving the middle fossa. METUODS:Twenty-five patients underwent lateral orbitotomies from April 2012 to July 2015. Excluding patients with solely intraorbital pathologies, 13 patients’ clinical and radiographic records were retrospectively reviewed. RESULTS:Signs/symptoms in the 13 patients (ages 28-81) included proptosis (69%), decreased visual acuity (31%), diplopia (54%), and afferent pupillary defect (69%). Pathologies were meningioma (8), esthesioneuroblastoma, lymphoma, chordoma, Ewing's sarcoma, and squamous cell carcinoma. Surgical goals were maximal safe resection in 8 patients, palliative debulking in 3 patients, and cavernous sinus biopsy in 2 patients. In 8 patients for whom maximal resection was the goal, 2 had gross total resection, while 6 had near-total resection. All patients (3) for whom palliation was the goal had symptomatic improvement. Both cavernous sinus biopsies obtained diagnostic tissue without complications. All patients with proptosis (n = 9) and diplopia (n = 7), and 2 of 4 patients with decreased visual acuity had improvement in their symptoms. No patient reported worsening of their symptoms. Mean follow-up was 12 mo (2-30 mo). Complications included oculorrhea (1), pseudomeningocele (2), transient ptosis (2), and forehead numbness (1). CONCLUSION:The lateral orbitotomy is a promising approach for carefully selected lesions with involvement of both the lateral orbit and middle cranial fossa. It provides minimally invasive access for biopsy, decompression, or resection.

BACKGROUND:Recent studies have demonstrated diffusion tensor imaging tractography of cranial nerves (CNs). Spatial and angular resolution, however, is limited with this modality. A substantial improvement in image resolution can be achieved with high-angle diffusion magnetic resonance imaging and atlas-based fiber tracking to provide detailed trajectories of CNs. OBJECTIVE:To use high-definition fiber tractography to identify CNs in healthy subjects and patients with brain tumors. METHODS:Five neurologically healthy adults and 3 patients with brain tumors were scanned with diffusion spectrum imaging that allowed high-angular-resolution fiber tracking. In addition, a 488-subject diffusion magnetic resonance imaging template constructed from the Human Connectome Project data was used to conduct atlas space fiber tracking of CNs. RESULTS:The cisternal portions of most CNs were tracked and visualized in each healthy subject and in atlas fiber tracking. The entire optic radiation, medial longitudinal fasciculus, spinal trigeminal nucleus/tract, petroclival portion of the abducens nerve, and intrabrainstem portion of the facial nerve from the root exit zone to the adjacent abducens nucleus were identified. This suggested that the high-angular-resolution fiber tracking was able to distinguish the facial nerve from the vestibulocochlear nerve complex. The tractography clearly visualized CNs displaced by brain tumors. These tractography findings were confirmed intraoperatively. CONCLUSION:Using high-angular-resolution fiber tracking and atlas-based fiber tracking, we were able to identify all CNs in unprecedented detail. This implies its potential in localization of CNs during surgical planning. ABBREVIATIONS:CN, cranial nerveDSI, diffusion spectrum imagingDTI, diffusion tensor imagingHCP, Human Connectome ProjectHDFT, high-definition fiber tractographyMLF, medial longitudinal fasciculusODF, orientation distribution functionROI, region of interest.

OBJECT Occipital neuralgia (ON) causes chronic pain in the cutaneous distribution of the greater and lesser occipital nerves. The long-term efficacy of cervical dorsal root rhizotomy (CDR) in the management of ON has not been well described. The authors reviewed their 14-year experience with CDR to assess pain relief and functional outcomes in patients with medically refractory ON. METHODS A retrospective chart review of 75 ON patients who underwent cervical dorsal root rhizotomy, from 1998 to 2012, was performed. Fifty-five patients were included because they met the International Headache Society's (IHS) diagnostic criteria for ON, responded to CT-guided nerve blocks at the C-2 dorsal nerve root, and had at least one follow-up visit. Telephone interviews were additionally used to obtain data on patient satisfaction. RESULTS Forty-two patients (76%) were female, and the average age at surgery was 46 years (range 16-80). Average follow up was 67 months (range 5-150). Etiologies of ON included the following: idiopathic (44%), posttraumatic (27%), postsurgical (22%), post-cerebrovascular accident (4%), postherpetic (2%), and postviral (2%). At last follow-up, 35 patients (64%) reported full pain relief, 11 (20%) partial relief, and 7 (16%) no pain relief. The extent of pain relief after CDR was not significantly associated with ON etiology (p = 0.43). Of 37 patients whose satisfaction-related data were obtained, 25 (68%) reported willingness to undergo repeat surgery for similar pain relief, while 11 (30%) reported no such willingness; a single patient (2%) did not answer this question. Twenty-one individuals (57%) reported that their activity level/functional state improved after surgery, 5 (13%) reported a decline, and 11 (30%) reported no difference. The most common acute postoperative complications were infections in 9% (n = 5) and CSF leaks in 5% (n = 3); chronic complications included neck pain/stiffness in 16% (n = 9) and upper-extremity symptoms in 5% (n = 3) such as trapezius weakness, shoulder pain, and arm paresthesias. CONCLUSIONS Cervical dorsal root rhizotomy provides an efficacious means for pain relief in patients with medically refractory ON. In the appropriately selected patient, it may lead to optimal outcomes with a relatively low risk of complications.

OBJECT The aim of this study was to evaluate the value of intraoperative neurophysiological monitoring (IONM) using electromyography (EMG), brainstem auditory evoked potentials (BAEPs), and somatosensory evoked potentials (SSEPs) to predict and/or prevent postoperative neurological deficits in pediatric patients undergoing endoscopic endonasal surgery (EES) for skull base tumors. METHODS All consecutive pediatric patients with skull base tumors who underwent EES with at least 1 modality of IONM (BAEP, SSEP, and/or EMG) at our institution between 1999 and 2013 were retrospectively reviewed. Staged procedures and repeat procedures were identified and analyzed separately. To evaluate the diagnostic accuracy of significant free-run EMG activity, the prevalence of cranial nerve (CN) deficits and the sensitivity, specificity, and positive and negative predictive values were calculated. RESULTS A total of 129 patients underwent 159 procedures; 6 patients had a total of 9 CN deficits. The incidences of CN deficits based on the total number of nerves monitored in the groups with and without significant free-run EMG activity were 9% and 1.5%, respectively. The incidences of CN deficits in the groups with 1 staged and more than 1 staged EES were 1.5% and 29%, respectively. The sensitivity, specificity, and negative predictive values (with 95% confidence intervals) of significant EMG to detect CN deficits in repeat procedures were 0.55 (0.22-0.84), 0.86 (0.79-0.9), and 0.97 (0.92-0.99), respectively. Two patients had significant changes in their BAEPs that were reversible with an increase in mean arterial pressure. CONCLUSIONS IONM can be applied effectively and reliably during EES in children. EMG monitoring is specific for detecting CN deficits and can be an effective guide for dissecting these procedures. Triggered EMG should be elicited intraoperatively to check the integrity of the CNs during and after tumor resection. Given the anatomical complexity of pediatric EES and the unique challenges encountered, multimodal IONM can be a valuable adjunct to these procedures.

BACKGROUND:Treatment of low-pressure hydrocephalus (LPH) may require prolonged external ventricular drainage (EVD) at sub-zero pressures to reverse ventriculomegaly. Endoscopic third ventriculostomy (ETV) has been used in the treatment of noncommunicating hydrocephalus; however, indications for ETV are expanding. METHODS:Patients with the diagnosis of LPH as defined by the Pang and Altschuler criteria who underwent sub-zero drainage treatment over an 8-year period were included. Patients were divided into two cohorts based on whether or not ETV was employed during their treatment. Time from EVD placement to internalization of shunt was recorded for both groups; time from ETV to placement of shunt was recorded for the patients undergoing ETV. RESULTS:Sixteen adult patients with LPH were managed with sub-zero drainage method. Ten (62.5%) patients did not undergo ETV and the average time from first ventriculostomy to shunting was 73 days (range 14-257 days). Six (37.5%) patients underwent ETV during the course of their treatment; average time from initial ventriculostomy to shunt was 114 days (range 0-236 days) (P = 0.16). Time from development of LPH to ETV ranged from 28 days to 6.5 months. In the ETV group, of the 4 patients who underwent shunting, the average time to shunting following ETV was 15.25 days. CONCLUSIONS:ETV can be used successfully in the management of refractory LPH to decrease the duration of EVD.

BACKGROUND:Diagnosing normal pressure hydrocephalus (NPH) remains challenging. Most clinical tests currently used to evaluate suspected NPH patients for shunt surgery are invasive, require inpatient admission, and are not without complications. An objective, noninvasive, and low-cost alternative would be ideal. METHODS:A retrospective review was performed of prospectively collected dynamic gait index (DGI) scores, obtained at baseline and on every day of a 3- to 5-day lumbar cerebrospinal fluid (CSF) drainage trial on patients with suspected NPH at our institution. RESULTS:Between 2003 and 2014, 170 patients were suspected to have primary NPH (166, 97.6%) or secondary NPH (4, 2.4%). Using responsiveness to lumbar CSF drainage and subsequent shunting as the reference standard, we found that a baseline DGI ≥ 7 was found to have significant ability in selecting patients for permanent CSF diverting shunt surgery: sensitivity of 84.2% (95% confidence interval [95% CI]: 75.6%-90.2%), specificity of 80.6% (95% CI 70.0%-88.0%), and diagnostic odds ratio of 22.1 (95% CI 9.9-49.3). CONCLUSIONS:A baseline DGI ≥ 7 appears to provide an objective, low-cost, noninvasive measure to select patients with suspected NPH for a positive response to CSF diversion with high sensitivity, specificity and diagnostic odds ratio.

BACKGROUND:The endoscopic endonasal approach (EEA) for craniocervical lesions involving the lower clivus and occipital condyles carries an unclear risk of atlanto-occipital (AO) instability requiring arthrodesis. OBJECTIVE:Elucidate risk factors for AO instability following EEA for clival lesions. METHODS:We reviewed patients with clival tumors who underwent EEA at our institution between 2002 and 2012. Resection of the lower clivus, foramen magnum, AO joint, and occipital condyles were evaluated on fine-cut postoperative computed tomography. RESULTS:Two hundred twelve patients (mean age 47.9 years, 57.1% male) underwent transclival EEA for lower clival lesions. In addition to the lower clivus, resection involved the condyle in 14.2% of patients, the foramen magnum in 16.5%, and the AO joint in 1.4%. Quantification of condyle resection revealed complete resection in 3 cases, 75% resection in 8 cases, 50% resection in 6 cases, and 25% resection in 13 cases. Seven of these patients had EEA combined with an open, far-lateral approach. In total, 7 patients required arthrodesis following EEA (3.3%), 4 of them after a combined approach. All patients who underwent arthrodesis had primary bone tumors such as chordoma, chondrosarcoma, or osteosarcoma (P = .022). Degree of condyle resection was a significant factor predisposing to occipitocervical instability (P = .001 and P < .001 for 75% and 100% condyle resection, respectively). Use of a combined approach was significantly associated with arthrodesis (P < .001). CONCLUSION/CONCLUSIONS:EEA resection of the occipital condyles that results in greater than 75% condyle resection or EEA in combination with an open approach significantly increases the risk of AO instability and likely necessitates AO fixation. ABBREVIATIONS/BACKGROUND:AO, atlanto-occipitalEEA, endoscopic endonasal approachOC, occipitocervical.