Hearing preservation outcomes using direct cranial nerve eight and auditory brainstem response neuromonitoring in the resection of vestibular schwannomas.

OBJECTIVE: Advancements in microsurgical technique and technology continue to improve outcomes in patients with skull base tumor. The primary cranial nerve eight monitoring systems used in hearing preservation surgery for vestibular schwannomas (VSs) are direct cranial nerve eight monitoring (DCNEM) and auditory brainstem response (ABR), although current guidelines are unable to definitively recommend one over the other due to limited literature on the topic. Thus, further research is needed to determine the utility of DCNEM and ABR. The authors performed a retrospective cohort study and created an interactive model that compares hearing preservation outcomes based on tumor size in patients receiving ABR+DCNEM and ABR-only monitoring. METHODS: Twenty-eight patients received ABR+DCNEM and 72 patients received ABR-only monitoring during VS hearing preservation surgery at a single tertiary academic medical center between January 2008 and November 2022. Inclusion criteria consisted of adult patients with a preoperative American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) hearing classification of A or B. Tumor size was measured as the maximal medial to lateral length, including the internal auditory canal component. RESULTS: Overall hearing preservation (word recognition score [WRS] > 0%) was achieved in 31 patients with ABR-only monitoring (43.1%) and in 18 patients with ABR+DCNEM (64.3%). Serviceable hearing preservation (AAO-HNS class A or B) was attained in 19 patients with ABR-only monitoring (26.4%) and in 11 patients with ABR+DCNEM (39.3%). There was no difference in overall hearing preservation between the two groups (p = 0.13). Change in tumor size was not associated with the odds of serviceable hearing preservation for the ABR-only group (p = 0.89); however, for ABR+DCNEM, there was some indication of an interaction between tumor size and the association of ABR+DCNEM versus ABR-only monitoring, with the odds of serviceable hearing preservation at p = 0.089. Furthermore, with ABR+DCNEM, every 0.5-cm increase in tumor size was associated with a decreased odds of serviceable hearing preservation on multivariable analysis (p = 0.05). For both overall and serviceable hearing preservation, a worse preoperative AAO-HNS classification was associated with a decreased odds of preservation (OR 0.43, 95% CI 0.19-0.97, p = 0.042; OR 0.17, 95% CI 0.053-0.55, p = 0.0031, respectively). CONCLUSIONS: The result of this interactive model study proposes that there may be a higher chance of hearing preservation when using ABR+DCNEM rather than ABR alone for smaller tumors, with that relationship reversing as tumor size increases.

Long-term quality of life outcomes in patients undergoing microsurgical resection of vestibular schwannoma.

Background: While previous studies have assessed patient reported quality of life (QOL) of various vestibular schwannoma (VS) treatment modalities, few studies have assessed QOL as related to the amount of residual tumor and need for retreatment in a large series of patients. Objective: To assess patient reported QOL outcomes following VS resection with a focus on extent of resection and retreatment. Methods: A retrospective chart review was performed using single-center institutional data of adult patients who underwent VS resection by the senior authors between 1989-2018 at Loyola University Medical Center. The Penn Acoustic Neuroma Quality of Life (PANQOL) survey was sent to all patients via postal mail. Results: Fifty-five percent of 367 total patients were female with a mean age of 61.6 years (SD 12.63). The mean period between surgery and PANQOL response was 11.4 years (IQR: 4.74-7.37). The median tumor size was 2 cm (IQR: 1.5-2.8). The mean total PANQOL score was 70 (SD 19). Patients who required retreatment reported lower overall scores (µdiff = -10.11, 95% CI: -19.48 to -0.74; p = 0.03) and face domain scores (µdiff = -20.34, 95% CI: -29.78 to -10.91; p < .001). There was no association between extent of resection and PANQOL scores in any domain. Conclusion: In an analysis of 367 patients who underwent microsurgical resection of VS, extent of resection did not affect PANQOL scores in contrast to previous reports in the literature, while the need for retreatment and facial function had a significant impact on patient-reported outcomes.

Is There a Plateau to the Learning Curve for Acoustic Neuroma Resection?-Experience and Outcomes from a Single Interdisciplinary Team Over Thirty Years.

Objective The evolution of acoustic neuroma (AN) care continues to shift focus on balancing optimized tumor resection and control with preservation of neurological function. Prior learning curve analyses of AN resection have demonstrated a plateau between 20 and 100 surgeries. In this study of 860 consecutive AN surgeries, we investigate the presence of an extended learning curve tail for AN resection. Methods A retrospective cohort study of AN resections by a single interdisciplinary team between 1988 and 2018 was performed. Proportional odds models and restricted cubic splines were used to determine the association between the timing of surgery and odds of improved postoperative outcomes. Results The likelihood of improved postoperative House-Brackmann (HB) scores increased in the first 400 procedures, with HB 1 at 36% in 1988 compared with 79% in 2004. While the probability of a better HB score increased over time, there was a temporary decrease in slope of the cubic spline between 2005 and 2009. The last 400 cases continued to see improvement in optimal HB outcomes: adjusted odds of HB 1 score were twofold higher in both 2005 to 2009 (adjusted odds ratio [aOR]: 2.11, 95% confidence interval [CI]: 1.38-3.22, p < 0.001) and 2010 to 2018 (aOR: 2.18, 95% CI: 1.49-3.19, p < 0.001). Conclusion In contrast to prior studies, our study demonstrates the steepest growth for learning, as measured by rates of preservation of facial function outcomes (HB 1), occurs in the first 400 AN resections. Additionally, improvements in patient outcomes continued even 30 years into practice, underlining the importance of lifelong learning.

Internal Auditory Canal Glioneural Hamartoma: A Rare Mass Masquerading as a Vestibular Schwannoma.

Glioneural hamartomas are exceedingly rare lesions. When localized to the internal auditory canal (IAC), they can cause symptoms referrable to seventh and eighth cranial nerve compression. Here, the authors present a rare case of an IAC glioneural hamartoma. A 57-year-old male presented for evaluation of presumed intracanalicular vestibular schwannomas found on work-up of dizziness and progressive right-sided hearing loss. Surgical intervention pursued progressive symptoms and new onset headaches. The patient underwent uncomplicated retrosigmoid craniectomy for gross total resection. Histopathological evaluation revealed a glioneural hamartoma. A MEDLINE database search used the terms' cerebellopontine angle' OR 'internal auditory canal' AND 'hamartoma' OR 'heterotopia'. Clinicopathological characteristics and outcomes of the present case were compared to those in the literature. The literature review yielded nine articles describing 11 cases (eight females, three males; median age 40 years, range 11-71) of intracanalicular glioneural hamartomas. Patients most commonly presented with hearing loss and were presumed to have a diagnosis of vestibular schwannoma before histologic diagnosis. Glioneural hamartomas are rare lesions that may be found in the IAC. Although benign, they may be safely resected for cranial nerve function preservation goals with a low risk of recurrence.

Intraoperative electrical stimulation for persistent, post-traumatic facial paralysis.

Approximately 7-10% of temporal bone fractures result in facial nerve paralysis. Treatment is dependent upon the severity of the nerve trauma and can range from conservative medical management to surgical intervention. A study by Hato et al. detailed the relationship between surgical timing and recovery rate for patients with facial nerve palsy secondary to temporal bone trauma. The rates of complete recovery and good recovery decline that the longer surgical intervention is delayed. We present the case of a 14-year-old male with a temporal bone fracture and delayed onset right-sided facial paralysis. This patient was treated with a transmastoid middle cranial fossa (MCF) approach with intraoperative electrical stimulation of the perigeniculate portion of the facial nerve. Despite a 53-day delay between trauma and surgical intervention, the patient's facial function improved from House Brackmann (HB) grade VI to grade II within 6 months. Intraoperative facial nerve stimulation, which we have previously used for unresolved Bell's palsy, may be useful for patients with post-traumatic, persistent facial paralysis.

Assessing Surgical Approaches for Acoustic Neuroma Resection: Do Patients Perceive a Difference in Quality-of-Life Outcomes?

OBJECTIVE: The objective of this study is to further patient-physician discussion regarding postoperative quality of life expectations after surgical acoustic neuroma resection. STUDY DESIGN: This study is retrospective prospective. Qualifying patients were identified and administered Penn Acoustic Neuroma Quality-of-Life (PANQOL) Scale. SETTING: The setting was Loyola University Chicago Health System. PATIENTS: Three hundred twenty-six patients at our center with surgically resected acoustic neuroma between January 1990 and July 2021 completed the PANQOL. INTERVENTIONS: During postresection follow-up visits, patients were administered the PANQOL survey. MAIN OUTCOME MEASURES: The total PANQOL is comprised of questions addressing quality of life in seven domains of hearing, balance, face, energy, pain, health, and anxiety. Univariate and multivariable analyses were performed to test for associations between surgical approach and/or patient characteristics. RESULTS: Patients who were treated with retrosigmoid approach reported slightly higher PANQOL pain scores when compared with translabyrinthine approach. No association was found between responses on hearing PANQOL and surgical approach. No association was found between approach and total PANQOL score. However, on average female patients reported lower total PANQOL compared with male patients. CONCLUSION: The lack of association between patient response on hearing PANQOL and surgical approach illustrates the impact of preoperative patient counseling in appropriately setting patient expectations. The difference in pain PANQOL response may be due to a higher rate of occipital neuralgia due to incision placement and soft tissue retraction in the retrosigmoid patient group. Surgeons may consider alternative surgical incisions and soft tissue dissection to improve patient's quality of life with respect to postoperative pain.

Occipital Neuralgia following Acoustic Neuroma Resection.

Background While postoperative outcomes of acoustic neuroma (AN) resection commonly consider hearing preservation and facial function, headache is a critical quality of life factor. Postoperative headache is described in the literature; however, there is limited discussion specific to occipital neuralgia (ON) following AN resection. Objective The aim of this study is to investigate the effectiveness of conservative management and surgery. Methods We conducted a retrospective review of 872 AN patients who underwent resection at our institution between 1988 and 2017 and identified 15 patients (1.9%) that met International Classification of Headache Disorders criteria for ON. Results Of the 15 ON patients, surgical approaches included 13 (87%) retrosigmoid (RS), one (7%) translabyrinthine (TL), and one (7%) combined RS + TL. Mean clinical follow-up was 119 months (11-263). Six (40%) patients obtained pain relief through conservative management, while the remaining nine (60%) underwent surgery or ablative procedure. Three (38%) patients received an external neurolysis, four (50%) received a neurectomy, one (13%) had both procedures, and one (13%) received two C2 to 3 radio frequency ablations. Of the nine patients who underwent procedural ON treatment, seven (78%) patients achieved pain relief, one patient (11%) continued to have pain, and one patient (11%) was lost to follow-up. Of the six patients whose pain was controlled with conservative management and nerve blocks, five (83%) found relief by using neuropathic pain medication and one (17%) found relief on nonsteroidal anti-inflammatory drug. Conclusion Our series demonstrates success with conservative management in some, but overall a minority (40%) of patients, reserving decompression only for refractory cases.

Economic Impact of Diagnostic Imaging in the Workup of Uncomplicated Bell's Palsy.

Objective Our primary objective is to identify the costs associated with imaging in the diagnostic workup of uncomplicated Bell's palsy. Our secondary objective is to identify a dollar amount spent on extraneous diagnostic testing on a state and national level. Design and Setting Retrospective chart analysis was performed at our tertiary care medical center between 2007 and 2018. International Statistical Classification of Diseases-10 code G51.0 was used to identify patients with Bell's palsy seen by the senior author. A total of 163 patients were divided into two groups: those having received imaging and those diagnosed without imaging. The imaging group was then further subdivided by imaging modality: computed tomography (CT) only, magnetic resonance imaging (MRI) only, or both. There was a total of 138 scans in 115 patients. To quantify the amount spent by insurance companies or patients on these scans, net expected pay (NEP) for each modality was used as a representation of cost. The NEP for a CT was $618. The NEP for an MRI was $1,119. The NEP for both scans was $1,737. We extrapolated our results to a state and national level. Main Outcome Measurements Cost of workup; state and national economic burden. Results Extrapolating our data, we forecast that in Illinois and in the United States, over $2 million and $53 million, respectively, are spent on unnecessary imaging. Conclusion By highlighting an unnecessary financial burden, our study provides concrete evidence to support the American Academy of Otolaryngology's recommendation that clinicians should not perform routine imaging studies when diagnosing uncomplicated Bell's palsy.

Neurological Manifestations of Paragangliomas of the Head and Neck.

PURPOSE OF REVIEW: This paper will outline the clinical neurologic presentation and diagnostic evaluation of patients with paragangliomas of the head and neck. Contemporary management options will be outlined for these rare and complex tumors. RECENT FINDINGS: The majority of recent publications and research on these tumors are dedicated to traditional and robotic image-guided radiosurgery in the treatment of head and neck paragangliomas. Paragangliomas are rare, slow-growing tumors of the head and neck which usually cause silent cranial nerve deficits or compensated mild speech or swallowing symptoms. While radiologic surveillance is often the best treatment option, subtotal resection with case-specific radiosurgery is commonly used in patients with large tumors.

An institutional review of recurrent pleomorphic adenoma of the parotid gland.

OBJECTIVE: Surgical resection is standard treatment for pleomorphic adenoma (PA) of the parotid gland. A small number (2-5%) of these tumors recur. Recurrence usually necessitates reoperation, which is technically challenging and puts the facial nerve (FN) at risk. The aim of this study is to characterize the recurrent parotid PA population and compare outcomes after surgery for singly recurrent and multiply recurrent tumors. METHODS: This study was a retrospective chart review of patients at a single tertiary care academic medical center who underwent operations for recurrent PA of the parotid gland between 2007 and 2020. Demographic data, details of surgical interventions, pre- and postoperative FN function, and recurrence rates were studied. These factors were compared between patients with singly and multiply recurrent tumors. RESULTS: Thirty-eight patients met criteria: 4 patients presented for primary PA and subsequently recurred, 26 with a first recurrence, 7 with a second recurrence, and 1 with a fourth recurrence. Multiply recurrent PAs were more likely to require at least partial nerve sacrifice at the time of reoperation (P = 0.0092). Significantly worse long-term FN outcomes were seen following surgery for multiply recurrent PA (P = 0.008). There was no significant difference between the rate of re-recurrence following first revision surgery vs second-fourth revision surgery. Time to reoperation was significantly shorter between the first and second revision surgery than between the primary surgery and first revision (P = 0.0017). CONCLUSION: Surgery for recurrent PA incurs high risk to the FN, and this risk appears to increase in the setting of multiple recurrences.

Ganglion Cyst Presenting as an External Auditory Canal Mass.

A ganglion cyst of the temporomandibular joint is a benign lesion that may present as a mass on the anterior wall of the external auditory canal and should be differentiated from other skull base pathology prior to management.

Anaplastic Hemangiopericytoma of the Jugular Foramen: Case Report and Systematic Review.

BACKGROUND: Hemangiopericytomas (HPCs) and solitary fibrous tumors (SFTs) are rare tumors of mesenchymal origin. Here, the authors present a rare case of anaplastic HPC in the jugular foramen (JF). The authors also conduct a systematic review of the literature to examine the current fund of knowledge on JF HPC/SFTs. METHODS: A systematic MEDLINE search was conducted using key words "hemangiopericytoma" OR "solitary fibrous tumor" AND "jugular foramen" OR "extracranial" OR "skull base." Clinicopathologic characteristics and outcomes of the present case were reviewed and compared with those in the literature. RESULTS: A 41-year-old male, who had undergone stereotactic radiation therapy 6 years ago for a presumed glomus jugulare tumor, presented to our institution with worsening dysphagia, hoarseness, persistent tongue weakness, and radiographic evidence of tumor progression. The patient underwent uncomplicated gross total resection with sacrifice of the infiltrated hypoglossal nerve. Histopathologic evaluation revealed anaplastic HPC/SFT (World Health Organization grade III). Review of the literature yielded 9 additional cases of JF HPC/SFT in 5 males (56%) and 4 females (44%), with a mean age of 49.6 years old. Patients commonly presented with pain (37.5%) and lower cranial nerve deficits (100%). Preoperative diagnoses included glomus jugulare (n = 2) or JF schwannomas (n = 3). All patients underwent microsurgical resection of the lesion, except for 1 who refused all treatment after diagnostic biopsy. CONCLUSION: The authors present the only reported case of anaplastic HPC of the JF. The illustrative case and those found on systematic review of the literature highlight the importance of tissue diagnosis and appropriate management.

Fetal Bovine Collagen Grafts for Repair of Tegmen Defects and Encephaloceles Via Middle Cranial Fossa Approach.

To evaluate the use of commercially available allogenic dural graft materials made of fetal bovine collagen, we present an analysis of our case series with use of autologous and allogenic graft materials. Patients who underwent surgical repair of a tegmen tympani defect associated with ipsilateral conductive hearing loss and cerebrospinal fluid (CSF) otorrhea using a middle cranial fossa (MCF) approach from 2004 to 2018 at Loyola University Medical Center were included. Resolution of CSF otorrhea, audiologic outcomes, facial nerve preservation, and surgical complications was analyzed. Thirty-three patients with an average age of 55.3 years (range: 21-78, standard deviation [SD]: 12.9) and body mass index of 34.4 (range: 22-51, SD: 7.4) underwent an MCF repair of a tegmen and dural defect. All patients presented with CSF otorrhea and conductive hearing loss ipsilateral to the defect. Repairs were made with combinations of allograft and autograft in 17 cases, allograft only in 15 cases, and autograft only in 5 cases. Improvement in hearing was noted in 33 cases, and resolution of CSF otorrhea was noted in 36 cases; one patient required repeat surgery which resolved CSF otorrhea. Three patients had minor complications; all these were in the autograft group. The MCF approach coupled with the use of fetal bovine collagen grafts is a safe and viable method to repair tegmen tympani and associated dural defects with salutary outcomes and low morbidity.

Glomus Vagale Tumor Resection: 2-Dimensional Operative Video.

A 37-yr-old female with prior transient left facial paralysis presented with hearing loss, headaches, and resolved transient right facial paralysis. The neurological examination demonstrated normal facial movement, left hearing loss, and left vocal cord weakness. Magnetic resonance imaging demonstrated a >3 cm left paraganglioma traversing the jugular foramen. After obtaining informed consent from the patient, the tumor was embolized and then resected via a combined left postauricular infratemporal fossa and transcervical approach with cranial nerve monitoring. The ossicles were removed and the vertical segment of the facial nerve was skeletonized. The jugular bulb was identified in the hypotympanum and the petrous carotid artery was exposed. The digastric muscle was reflected inferiorly and the extratemporal facial nerve was identified. The stylomandibular ligament was transected to unlock the exposure to the infratemporal fossa. The external carotid branches were ligated. The vagus nerve and cervical sympathetic chain were infiltrated with tumor, requiring resection. The presigmoid dura and occluded jugular bulb were opened to complete the tumor resection, while preserving the medial wall. Despite anatomic preservation, the glossopharyngeal, accessory, and hypoglossal nerves were postoperatively weak and a facial paralysis recovered after 1 wk. Magnetic resonance imaging at 1 yr demonstrated a clean jugular foramen, although a thin rim of tumor remained around the petrous carotid.

Osteoradionecrosis of the skull base.

Radiation therapy (RT) is often necessary for the treatment of head and neck cancers. Osteoradionecrosis (ORN) is a rare, but potentially serious complication of RT. RT leads to the destruction of vasculature in radiated tissue causing hypoxia and tissue necrosis. ORN can occur in any bone, but bones with naturally poor blood supply appear to be more susceptible. Bones of the skull base are susceptible, with ORN occurring in the anterior, central, and lateral skull base. Risk factors include cancer type and location, radiation dose, and a variety of patient factors. Patients often present with pain, bleeding, and foul odor and are typically found to have exposed and necrotic bone. Treatment options vary depending on the severity, but typically include pentoxifylline and vitamin E as well as surgical debridement, with less evidence supporting hyperbaric oxygen therapy. Recognition and prompt treatment of ORN will allow for improved patient outcomes.

Pediatric vestibular schwannomas: case series and a systematic review with meta-analysis.

OBJECTIVE: Sporadic unilateral vestibular schwannomas are rare in the pediatric population. Little has been reported in the literature on the presentation, tumor size, response to surgical treatment, and recurrence rates in these younger patients. The authors' goal was to describe their institutional experience with pediatric sporadic vestibular schwannomas and to conduct a meta-analysis of the existing literature to provide further insight into the presentation, tumor characteristics, and surgical outcomes for these rare tumors to help direct future treatment strategies. METHODS: The authors performed a retrospective review of all patients 21 years of age or younger with unilateral vestibular schwannomas and without neurofibromatosis type 2 who underwent resection by the senior authors between 1997 and 2019. A systematic review of the literature and meta-analysis was also performed by entering the search terms "pediatric" and "vestibular schwannoma" or "acoustic neuroma," as well as "sporadic" into PubMed. Presentation, treatment, clinical outcomes, and follow-up were analyzed. RESULTS: Fifteen patients were identified at the authors' institution, ranging in age from 12 to 21 years (mean 16.5 years). Common presenting symptoms included hearing loss (87%), headache (40%), vertigo (33%), ataxia (33%), and tinnitus (33%). At the time of surgery, the mean tumor size was 3.4 cm, with four 1-cm tumors. Four patients had residual tumor following their first surgery, 3 (75%) of whom had significant radiographic regrowth that required further treatment. The literature review identified an additional 81 patients from 26 studies with patient-specific clinical data available for analysis. This resulted in a total of 96 reported patients with an overall average age at diagnosis of 12.1 years (range 6-21 years) and an average tumor size of 4.1 cm. CONCLUSIONS: Pediatric vestibular schwannomas present similarly to those in adults, although symptoms of mass effect are more common, as these tumors tend to be larger at diagnosis. Some children are found to have small tumors and can be successfully treated surgically. Residual tumors in pediatric patients were found to have a higher rate of regrowth than those in their adult counterparts.

Primary Paraganglioma of the Facial Canal: An Evidence-Based Approach.

OBJECTIVES: To perform an evidence-based review evaluating presenting symptoms, imaging, and management for primary paragangliomas of the facial canal (PPFCs). DATA SOURCES: PubMed/MEDLINE, Embase, Cochrane Library, and Web of Science. REVIEW METHODS: Studies were assessed for quality of evidence and bias with the Cochrane bias tool, GRADE, and MINORS criteria. Demographic data, imaging modalities, management strategies, and status at last follow-up were obtained. RESULTS: Sixteen studies met inclusion criteria. In total, 21 patients with PPFCs were identified, 19 of which were histologically confirmed. Most common presenting symptoms included unilateral facial nerve dysfunction (n = 14, 73.7%) and pulsatile tinnitus (n = 8, 42.1%). Mean time from reported onset of facial dysfunction was 17.8 months. Computed tomography findings included an expanded descending facial nerve canal (n = 13, 76.5%). All cases with magnetic resonance imaging reported enhancement with contrast. Of the 18 patients who had surgery, 16 (88.9%) underwent full tumor resection while 1 (5.6%) had partial tumor debulking with adjuvant radiotherapy. Overall improvement in facial weakness was documented in 5 of 9 patients (55.6%) with initial facial nerve dysfunction and >6-month follow-up. No evidence of tumor recurrence was reported. CONCLUSIONS: PPFCs are extraordinarily rare vascular neoplasms of the temporal bone. Early imaging with both computed tomography and magnetic resonance imaging is essential for narrowing the differential diagnosis, assessing the extent of tumor invasion, and accurate surgical planning. Surgical tumor resection with subsequent facial nerve reconstruction is recommended for patients with facial nerve dysfunction, while tumor biopsy or debulking may be indicated when normal facial movement in present.

Tarik Syndrome: Reversible Postoperative Blindness Secondary to Occipital Seizures.

BACKGROUND: Postoperative blindness is a devastating surgical complication. Although usually associated with prolonged cardiac and prone spinal operations, it may follow other procedures as well. Postoperative blindness is most commonly caused by a vascular etiology, but it can more rarely be caused by status epilepticus. We have previously reported a case of this phenomenon following a staged spinal deformity surgery. CASE DESCRIPTION: Here we report 2 additional cases following a skull base procedure and a single stage lumbar spine surgery. In all instances, rapid recognition that the patients' blindness was due to occipital seizures resulted in acute antiepileptiform treatment and full restoration of vision. CONCLUSIONS: Although a rare phenomenon, this syndrome, first recognized and described by Tarik F. Ibrahim, should be considered in any patient with postoperative visual impairment.

Effect of Institutional Volume on Acoustic Neuroma Surgical Outcomes: State Inpatient Database 2009-2013.

BACKGROUND: Evolving technologies and health care quality metrics have altered treatment algorithms for acoustic neuromas (ANs), increasing trends toward observation and radiosurgery, with proportionate declines in use of microsurgery. A correlation between increasing surgical volumes and superior outcomes has been investigated previously in numerous surgical diseases, including AN. OBJECTIVE: To re-evaluate the volume-outcome relationship of AN resection in a changing health care system, with evolving treatment strategies. METHODS: Patients who underwent AN resection between 2009 and 2013 were retrospectively identified in the State Inpatient Database subset of the Healthcare Cost and Utilization Project. Generalized linear mixed-effect models were used to assess odds of various outcome measures (length of stay [LOS], discharge disposition, and facial nerve or severe clinical complications). Institutions were grouped into low-volume centers (1-6 cases/year) and high-volume centers (HVC; ≥31 cases/year) for analysis. RESULTS: A total of 1873 patients underwent AN resection between 2009 and 2013 with a mean age of 50.1 ± 14.1 years (±standard deviation). For each additional case treated annually, patients were 2% (odds ratio [OR], 0.98; 95% confidence interval, 0.96-0.99) less likely to experience a severe complication (P = 0.004). Each additional case also trended toward a decreased rate of facial nerve complications and nonroutine discharge. Inpatient LOS was also shorter for patients at HVCs (median, 4 vs. 5 days; P < 0.001). CONCLUSIONS: Despite a relative decline in microsurgery compared with previous eras, care at HVCs is still associated with superior short-term outcomes, such as decreased LOS, facial nerve or other severe complications, and nonroutine discharges.

Cranial Nerve Preservation Following Surgical Treatment for Epidermoid Cysts of the Posterior and Middle Fossae.

Epidermoid cysts are rare lesions, accounting for 0.2 to 1.8% of all intracranial tumors. They most commonly occur in the cerebellopontine angle where they may cause a breadth of neurologic complications due to mass effect on the nearby cranial nerves (CN), vascular structures, and the brain stem. Treatment of epidermoid cysts is surgical, with the goal of complete resection using microsurgical technique and even more importantly preservation of the involved CNs, vasculature, and brain parenchyma. Successful surgery can result in total resolution of symptoms, but, in certain situations, may not be advisable due to adherence, scarring, or inflammation making dissection of CN fascicles difficult and possibly hazardous. We conducted a retrospective review from 1998 to 2016 and compiled a series of 28 skull base epidermoid cysts operated on at our institution. Cases were evaluated for presenting symptoms, history of prior resection, and postoperative results including CN function, extent of resection, residual tumor, and need for reoperations. The average tumor size (largest diameter) was 3.9 cm with a range of 1 to 7cm. Eighteen of twenty-eight (64%) patients underwent a gross total resection and ten underwent subtotal resection. No patients, whether presenting with CN deficits or not, experienced permanent worsening of CN function following surgery. Complete resection of epidermoid cysts should remain a high priority of therapy, but, in our opinion, preservation of CN function should be a primary goal, determining the extent of resection to provide patients with the highest quality of life possible following surgery.