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OBJECTIVE Analyze delayed facial nerve palsy (DFNP) following resection of vestibular schwannoma (VS) to describe distinct characteristics and facial nerve (FN) functional course. STUDY DESIGN Prospective cohort with retrospective review. SETTING Academic medical center. PATIENTS Consecutive patients undergoing VS resection 11/2017 to 08/2020. Exclusion criteria: preoperative House-Brackmann (HB) ≥ III, postoperative HB ≥ III without delayed palsy

OBJECTIVE To determine the degree to which electrocochleography (ECoG) correlates with auditory and vestibular outcomes after repair of superior semicircular canal dehiscence (SSCD) via transmastoid (TM) and middle cranial fossa (MCF) approaches. STUDY DESIGN Retrospective review. SETTING Academic tertiary referral center. PATIENTS Adults with SSCD who underwent repair between 2005 and 2019. INTERVENTION Pre-, intra-, and postoperative ECoG. MAIN OUTCOME MEASURES Patient-reported vestibular and auditory symptoms; pre-, intra-, and postoperative ECoG measures, dizziness handicap inventory (DHI) scores. RESULTS Forty-six patients underwent SSCD repair (40 unilateral, six bilateral) between 2005 and 2019, including 24 MCF and 28 TM approaches. There were no differences in preoperative, intraoperative, or postrepair ECoG SP/AP values between the MCF and TM groups (p 0.12, 0.77, 0.58). Patients had subjective improvement in vestibular symptoms (or stable vestibular function in patients operated for predominantly auditory manifestations) with both approaches (MCF: 87.5%; TM: 92.3%; p 0.64). A successful outcome correlated with intraoperative SP/AP ratio normalization (p 0.0005). Similarly, DHI scores were similar in both groups preoperatively (p 0.66) and returned to their preoperative baseline postoperatively with both (p 0.52). Reported vestibular symptoms persisted or worsened more often in patients with migraine (66.6% vs. 28.9%, p 0.03), and with persistently abnormal ECoG measures, though the latter was not statistically significant in this population (38% vs. 15%, p 0.10). Patients had subjective improvement or stability in auditory symptoms using either approach (MCF: 96%; TM: 100%; p 0.62), also correlating with SP/AP ratio normalization (p 0.008). CONCLUSIONS Correction of abnormal preoperative ECoG reliably correlates to patient symptom improvement after SSCD repair. No significant differences in postoperative outcomes were noted between patients undergoing TM versus MCF repair. Circumspection regarding the likelihood of an ideal outcome after SSCD repair should be exercised when counseling patients with concomitant migraine. DEFINE PROFESSIONAL PRACTICE GAP AND EDUCATIONAL NEED It is not certain whether outcomes differ between the two dominant approaches for SSCD repair. Surgeons and patients would benefit from an intraoperative metric that reflects satisfactory plugging of SSCD. LEARNING OBJECTIVE To highlight the reliability and unique utility of intraoperative ECoG and demonstrate the correlation between ECoG correction and symptom improvement for SSCD repair. DESIRED RESULT To report subjective and objective outcomes following SSCD repair and encourage adoption of intraoperative ECoG monitoring. LEVEL OF EVIDENCE Level V. INDICATE IRB OR IACUC IRB review considers this study exempt (HUM00169949).

Objective Examine the impact of preoperative cochlear Fast Imaging Employing Steady-state Acquisition (FIESTA) and Constructive Interference in Steady State (CISS) signal intensity on hearing outcomes after middle cranial fossa (MCF) resection of acoustic neuroma (AN). Methods Adult patients (≥18 years) who underwent MCF AN resection for hearing preservation (HP) between November 2017 and September 2019 were retrospectively reviewed. All patients had preoperative word recognition score (WRS) ≥50%. HP was defined as postoperative WRS ≥50%. A neuroradiologist blinded to patients' clinical and audiometric outcomes reviewed patients' preoperative magnetic resonance images. Ipsilateral-to-contralateral cochlear FIESTA/CISS signal intensity ratios were determined using hand-drawn regions of interest focused on the cochlear fluid. Preoperative and postoperative pure tone average (PTA) and WRS were reviewed. Results Fifty-one patients were reviewed (60.8% female). Mean age was 47 years and mean tumor size 9.2 mm (±3.8). Hearing was preserved in 56.9% (n = 29). FIESTA/CISS signal ratios did not significantly differ between patients with and without HP. Lower FIESTA/CISS signal ratios correlated with greater declines in hearing (r = 0.322, p = 0.011 for PTA; and r = 0.384, p = 0.004 for WRS). On multivariate analysis accounting for tumor size and preoperative PTA/WRS, decreases in FIESTA/CISS signal ratios independently predicted greater declines in hearing by PTA (b = -100.9, p = 0.012) and WRS (b = 76.208), although the latter result was not statistically significant (p = 0.078). Conclusions Cochlear FIESTA/CISS signal intensity may be a predictor of postoperative hearing loss after MCF AN resection. In this cohort, degraded preoperative cochlear FIESTA/CISS signal strongly predicted postoperative hearing loss.Level of Evidence: IV.

Objective To test the feasibility and efficacy of a 3D exoscope navigation-guided middle cranial fossa (MCF) approach to the internal auditory canal (IAC); to potentially obviate the need to use dissection landmarks and instead, use the navigation probe as a guide to find structures and drill down to the IAC. Patients Cadaveric dissection of six temporal bones. Intervention Computed tomography temporal bone was performed with fiducials on each specimen before the dissection to employ the navigation system. Using a 3D exoscope with navigation by Synaptive (Toronto, Ontario, Canada), the MCF approach was performed. Main outcome measures Navigation accuracy, ability to identify critical structures, and ability to drill out the IAC successfully. Results All six specimens had the IAC successfully drilled out using the 3D exoscope. All dissections were performed with navigation and did not require dissecting out the greater superficial petrosal nerve and superior semicircular canal. One specimen used landmark dissection to confirm the IAC after navigation had been used to locate the IAC first. Navigation accuracy mean was 1.86 mm (range, 1.56-2.05 mm). Conclusion A 3D exoscope navigation-guided MCF approach to the IAC is feasible without landmark dissection.

Objective Conductive hearing loss (CHL) commonly arises in patients with spontaneous dehiscence of the tegmen of the temporal bone with meningoencephalocele (SME). The aim of this study was to further investigate 1) the potential mechanisms for CHL in this setting; 2) hearing outcomes following surgery to address SME, and 3) the possible causes of persistent CHL following surgery. Study design Retrospective case review. Setting Tertiary referral center. Patients and intervention Seven patients (six female; nine ears) who underwent middle cranial fossa repair of SME and were found to have a tegmen tympani dehiscence from October 2010 to September 2014 were included in the study. Main outcome measures Pre- and postoperative pure-tone audiometry. Results Eight of nine ears (89%) had audiometric hearing loss at presentation. Seven ears (78%) had an air bone gap of ≥15 dB; all of these had an encephalocele traversing the tegmen tympani defect, four had a middle ear effusion, and three had a simultaneous superior semicircular canal dehiscence (SSCCD). The CHL resolved postoperatively in four of seven ears. Two of the three ears with persistent CHL had SSCCD. Attic ossicular fixation was identified in the other patient and the CHL resolved after ossiculoplasty. Conclusions CHL associated with SME can be attributed preoperatively to ossicular chain fixation and synchronous SSCCD as well as the more commonly cited cerebrospinal fluid effusion and prolapse of meningoencephalocele onto the ossicular chain. Persistent postoperative CHL can also occur due to SSCCD and ossicular fixation by adhesions.

Objective To analyze audiometric data after surgical manipulation of the membranous labyrinth during plugging of superior semicircular canal dehiscence (SSCD) or posterior semicircular canal occlusion (PSCO) for benign paroxysmal positional vertigo. Study design Retrospective chart review. Setting Tertiary referral center. Patients Patients undergoing plugging of SSCD or PSCO between 2009 and 2019. Main outcome measures Pre- and postoperative audiometric data were collected per AAO-HNS guidelines. Hearing outcomes at initial and last follow-up were compared. Subanalyses were performed for surgical approach and age. Results Eighty-seven total procedures in 76 patients including 43 middle cranial fossa for SSCD, 29 transmastoid SSCD, and 15 PSCO. Mean preoperative air-conduction-pure-tone averages was 21.1±14.9 dB compared with 26.1 ± 19.6 dB at initial follow-up and 24.4 ± 18.6 dB at last follow-up (p = 0.006). Mean preoperative bone-conduction-pure-tone average was 14.3 ± 11.9 dB compared with 18.3 ± 15.6 dB at initial follow-up and 18.5 ± 16.9 dB at last follow-up (p 20 dB including one case of profound sensorineural hearing loss >55 dB. PSCO resulted in the most hearing loss at initial follow-up but largely resolves with time. Transmastoid approaches for SSCD resulted in more hearing loss compared with middle cranial fossa. Hearing outcomes were generally stable for SSCD approaches but showed improvement over time for PSCO. Age >50 was associated with greater hearing loss of 5.2 ± 11.1 dB compared with 1.3 ± 10.5 dB but did not reach statistical significance (p = 0.110). Conclusions Surgical manipulation of the membranous labyrinth results in statistically significant hearing loss in a pooled analysis. Transient hearing loss is observed in PSCO and TM SSCD plugging was associated with postoperative hearing loss. There was a trend toward increased hearing loss in patients >50 years old.

Objectives To review the outcomes of repairing tegmen dehiscence using the middle cranial fossa approach with a self-setting bone cement. Study design Retrospective case series. Setting Two academic tertiary hospitals. Patients All patients presenting for surgical repair of tegmen dehiscence and with postoperative follow-up for at least 6 months between October 2015 and July 2019. Intervention Surgical repair using a middle cranial fossa approach using a layered reconstruction with temporalis fascia and self-setting calcium phosphate bone cement. Main outcome measures Perioperative complications, recurrence of presenting symptoms/disease, hearing, and facial nerve grade. Results The cohort consisted of 22 patients with 23 tegmen dehiscence repairs (1 sequential bilateral repair). There were 16 males and 6 females with an average age at operation of 52.6 years. Repairs were left sided in 9, right sided in 12 patients, and bilateral in 1 patient. No patients had recurrence of presenting symptoms or disease at most recent follow-up. Preoperative hearing was maintained in all patients. Two patients (9% of repairs) experienced delayed partial temporary facial nerve weakness House-Brackman grade 2 and 4 which had recovered by 8 weeks postoperative. Conclusion We demonstrate a technique for repairing tegmen dehiscence of the middle cranial fossa floor that has excellent postoperative outcomes. We highlight potential technical challenges in this approach as well as the need for counseling for potential partial transient facial nerve dysfunction.

OBJECTIVE To characterize the radiologic findings of petrous apex cephalocele (PAC) in a patient cohort, and report the surgical management for three symptomatic PAC patients and cerebrospinal fluid (CSF) leak via the middle cranial fossa approach. STUDY DESIGN Retrospective case series. SETTING Academic center. PATIENTS Thirty-five patients with PAC were identified by review of the imaging archive between 2008 and 2019 (29 females; mean, 55 yrs; range, 4-86 yrs). All patients underwent magnetic resonance imaging of the skull base and/or computed tomography examination. INTERVENTIONS Surgical repair of PAC. MAIN OUTCOME MEASURES Radiologic features of PAC. RESULTS Radiological features of PAC: 25.7% bilateral; partial or expanded empty sella in 82.9%; arachnoid pits in 14.2%; and enlarged CSF space of optic nerve sheath in 20.0%. Coexisting pathology included temporal, sphenoid, and bilateral jugular foramen meningocele; as well as cribriform, middle crania fossa, and right temporal defect. Three case studies describing the surgical course of spontaneous CSF leak secondary to PAC were managed with the middle cranial fossa approach. CONCLUSIONS PAC is an exceedingly unusual cause for CSF leak in the adult and pediatric population. A middle fossa approach may be used to treat CSF leak as a result of PAC. Typically, CSF otorrhea originates from an encephalocele that extends via a bony defect in the tegmen tympani or tegmen mastoideum. However, on occasion the source of the CSF otorrhea is not via the tegmen, instead defects in the middle fossa floor, medial to the ridge for the gasserian ganglion (tubercle of Princeteau), need to be considered.

Objective To identify intraoperative neurophysiologic measures predictive of delayed progressive sensorineural hearing loss in the operative ear after a middle fossa approach (MCF) for resection of vestibular schwannoma (VS). Study design Retrospective review. Setting Academic, tertiary referral center. Patients Subjects with vestibular schwannoma who underwent a MCF microsurgical resection of VS were analyzed for individuals whose hearing was initially preserved but subsequently developed progressive sensorineural hearing loss in the operative ear. Thirty-seven patients were identified for whom audiologic and neurophysiologic data was available. Intervention Intraoperative neurophysiologic changes will correlate with delayed sensorineural hearing loss in the operative ear. Main outcome measures Audiometric evaluations, intraoperative electrocochleography (ECoG), and auditory brainstem response (ABR) measures. Results Twenty-five subjects experienced stable hearing or hearing loss in the operative ear comparable to the contralateral ear. Twelve subjects suffered a significant increase in the hearing asymmetry between ears. Deterioration in the amplitude of wave V of the ABR persisting at the close of tumor resection correlated with delayed sensorineural hearing loss in the operative ear (p 0.02, 5% mean improvement in the stable hearing group, versus a 14% decline with progressive asymmetry), but changes in ECoG or other auditory brainstem response parameters (p > 0.05) were not predictive. Conclusions Persisting amplitude reduction of wave V of the intraoperative ABR best correlates with delayed progressive sensorineural hearing loss in the operative ear. Neither persistent changes in ECoG, other ABR parameters, nor transient changes, correlated with delayed progressive sensorineural hearing loss in the operative ear.

OBJECTIVE Report the details of an unusual case of initially unilateral intradural spontaneous otogenic pneumocephalus in which the patient developed contralateral pneumocephalus after surgical repair of temporal bone and dural defects on the initial side. Discuss the lessons learned concerning management and pathophysiology of this rare case. PATIENT A 73-year-old male presenting with bilateral retro-orbital pain and headache was found to have unilateral intradural pneumocephalus in the temporal lobe with an adjacent defect in the temporal bone. INTERVENTION Surgical repair of the initial defect in the temporal bone and dura via a middle cranial fossa approach with obliteration of the mastoid cavity. RESULTS The patient's symptoms and degree of pneumocephalus on first affected side decreased initially after surgery. Two weeks after surgery he developed worsening pneumocephalus on the contralateral side in the temporal and frontal lobes with weakness and mild somnolence. This side was repaired via a similar technique without mastoid obliteration. Two weeks after surgery the patient recovered to normal level of consciousness with mild residual weakness. CONCLUSIONS Spontaneous otogenic intradural pneumocephalus is an extremely rare but serious condition related to defects in the temporal bone and dura. The precise mechanism by which this occurs is poorly understood. This unusual case where there were bilateral defects presenting with spontaneous otogenic pneumocephalus in sequence illustrates that it represents a rare sequelae of processes which thin the skull base. These processes should be addressed in addition to acute management of the defect and intracranial air.

OBJECTIVE Compare outcomes of middle cranial fossa approach (MCF) to vestibular schwannoma (VS) resection in patients 60 years of age and older to patients under 60. STUDY DESIGN Retrospective case series. SETTING Tertiary referral center. PATIENTS Charts of 216 consecutive VS patients over 18 years of age were reviewed to identify 67 patients who underwent MCF approach to VS resection between 2006 and 2017. INTERVENTION(S) Age at time of surgery. MAIN OUTCOME MEASURE(S) Measured outcomes included postoperative hearing results, facial nerve function, length of hospital stay, wound complications, cerebrospinal fluid leak, myocardial infarction, cerebrovascular accident, seizure, deep vein thrombosis, 30-day readmission, and return to operating room. RESULTS Sixty-seven patients underwent VS resection via MCF approach including 16 patients > = 60 years (mean 64.4 SD 3.3) and 51 patients

Objective To present a case of pediatric cholesteatoma that invaded the petrous apex (PA) and discuss the usefulness of preoperative three-dimensional (3D) surgical simulation on a personal computer (PC) and patient-specific 3D printed model-assisted surgery. Patient A 5-year-old boy with congenital cholesteatoma underwent a planned two-stage canal wall up mastoidectomy. The cholesteatoma had invaded the PA from a small space anterior to the superior semicircular canal (SSCC). During the removal of this lesion in the first surgery, the tip of a 1-mm round knife broke off and fell into the PA. The surgeon could not remove it, as it was thought that opening the space might damage the SSCC and the facial nerve (FN). Intervention Before the second surgery, a preoperative 3D surgical simulation on a PC was performed, and an approach to the PA via the triangle surrounded by the SSCC, FN, and middle cranial fossa, namely, the supracochlear approach, was discovered. A patient-specific 3D-printed model, which had been drilled to make each surface of the triangle including the SSCC, FN, and middle cranial fossa visible in the PC simulation surgery, was then created and a 3D-printed model-assisted surgery was planned. Results By placing the sterilized patient-specific 3D model close to the surgical field, the cholesteatoma and iatrogenic foreign body could be successfully removed from the PA without damaging the important surrounding structures. Conclusions Preoperative 3D surgical simulations and intraoperative patient-specific 3D-printed model-assisted surgeries are new, powerful tools that aid in performing challenging surgeries on temporal bones.

OBJECTIVE To determine short- and intermediate-term hearing preservation rates after microsurgical resection of vestibular schwannoma (VS). DATA SOURCES Systematic review of the Ovid, Cochrane, EMBASE, and Web of Science databases. STUDY SELECTION This study was restricted to full-text English-language articles detailing VS resection via the middle cranial fossa or retrosigmoid approaches. Documentation of pre- and posttreatment hearing outcomes with American Academy of Otolaryngology-Head and Neck Surgery, Gardner-Robertson, or word recognition score scales, as well as time to follow-up were required. Duplicate data sets, studies with >10% of patients with neurofibromatosis two, previous or nonsurgical VS treatment, case reports with

Background Few studies report hearing preservation following middle cranial fossa (MCF) floor defect repair. Objective To investigate audiological outcomes following MCF floor defect repair using a modified MCF suprapetrous approach. Study design Retrospective cohort. Setting Tertiary referral center. Patients Eleven patients, with MCF floor defects. Interventions MCF floor defect surgical repairs with either fascia or fascia and bone graft. Main outcome measured Hearing outcomes. Results Eleven patients (two men) aged 34 to 82 years (median, 62 yrs) were identified. All patients were operated on by the same two senior surgeons (M.P. and M.G.). One patient with conductive hearing loss (based on tuning fork test) was excluded from the analysis due to missing preoperative audiogram data. All patients had middle fossa plate defects leading to cerebrospinal fluid (CSF) otorrhoea, rhinorrhoea, or meningitis. Nine patients had retrieval of herniated contents from the defect. Five patients had repair with temporalis fascia and split calvarial bone graft, and six patients had repair with fascia only. Follow up audiogram was performed at a mean 7.5 months (range, 0.5-24 mo). There was no recurrent CSF leak during the follow up period. The 10 patients (90.9%, 95% confidence interval [CI] 60.1-100.6) who had complete audiologic data sets demonstrated a mean improvement of 18.86 dB (range, -7.5 to 33.75 dB) in hearing postoperatively. One of these patients acquired a 7.5 dB reduction in postoperative hearing due to post-procedural middle ear effusion which subsequently resolved. Hearing improvement following fascial graft alone versus fascial graft with bone was 12.5 and 26.5 dB, respectively (p Conclusion Middle fossa craniotomy with or without retrieval of herniated contents and floor reconstruction with fascia and bone is associated with improved hearing. Clinical efficacy of this technique, however, can be only fully established when a statistically meaningful number of cases have been performed.

Hypothesis Patient-specific 3D printed models are useful presurgical planning tools because they accurately represent the anatomy and drilling characteristics of the middle cranial fossa (MCF) approach to the internal auditory canal (IAC). Background The MCF approach to the IAC can be challenging due to variability of the bony architecture along the floor of the middle fossa. Patient-specific 3D printed models may enhance surgeon knowledge of a given patient's anatomy when preparing for MCF surgery. Methods Six temporal bone models were printed from photoacrylic resin based on CT data obtained from cadaveric specimens using a desktop stereolithography 3D printer. Critical structures to avoid injuring, the facial nerve and membranous labyrinth, were modeled as hollow cavities and filled with indicator paint. Two neurotologists each drilled three 3D printed models and the corresponding cadaveric specimens, and then completed a 41-item visual analog scale questionnaire (score range of each item: 0-10) to assess the model's accuracy, utility, and potential as a training tool. Results Drilling the model was favorably rated (median score 9.2; range 7.3-9.6) for its ability to provide surgeons with an accurate mental image of the corresponding cadaveric anatomy. Overall similarity of feel of drilling the model in comparison to human bone was moderate (median 7.6; range 6.6-9.0). Surgeons would use this model to prepare for future cases (median 9.4; range 5.1-9.9) and felt it had excellent utility for training purposes (median 9.3; range 8.4-9.9). Conclusions Patient-specific 3D printed models provide an anatomically accurate and favorable tool for preparing for MCF surgery.

Objective Evaluate the safety and efficacy of the ultrasonic bone aspirator (UBA) during middle cranial fossa (MCF) approach to vestibular schwannoma (VS). Study design Retrospective case series. Setting Tertiary referral center. Patients Charts of 192 consecutive VS patients over 18 years of age were reviewed to identify 65 patients who underwent MCF approach to VS resection between 2006 and 2017. A combination of UBA and high-speed drill (HSD) was used to decompress the internal auditory canal (IAC) in 25 patients and HSD alone was used in the other 40 patients. Intervention(s) Use of UBA during vestibular schwannoma surgery via MCF approach for decompression of the IAC. Main outcome measure(s) Postoperative facial nerve outcomes assessed by the House-Brackmann (HB) facial nerve grading scale. Rates of gross total resection (GTR) and cerebrospinal fluid (CSF) leak. Results There were no significant differences in postoperative facial nerve function, in rate of GTR of tumor, or in rate of CSF leak. In the UBA group 24/25 (96%) had postoperative HB grade I-II compared with 36/40 (90%) in the HSD group (p-value = 0.66). GTR was achieved in 25/25 (100%) in the UBA group compared with 38/40 (95%) in the HSD group (p-value = 1). In the UBA group, there were 0/25 (0%) cases of CSF leak compared with 1/40 (2.5%) in the HSD group (p-value = 1). Conclusions UBA use is a safe and effective alternative or adjunct to HSD during MCF approach to expose the IAC contents. This surgical tool allows for bone removal with low risk of injury to adjacent structures.

OBJECTIVE Traditionally, auditory brainstem implants (ABIs) have been placed via the translabyrinthine or retrosigmoid approaches. In select patients, a modified extended middle cranial fossa (xMCF) approach with tentorial ligation may be advantageous for vestibular schwannoma (VS) resection and auditory rehabilitation. This manuscript describes the application of this modification of the MCF approach for simultaneous VS resection and ABI placement. PATIENTS Patients with neurofibromatosis type 2, profound bilateral sensorineural hearing loss, single functioning sigmoid/jugular venous system, and giant (>4 cm) VS. INTERVENTIONS Simultaneous VS resection and ABI placement via a modified xMCF approach with tentorial ligation. MAIN OUTCOME MEASURES Extent of tumor removal and brainstem decompression, access to lateral recess of the fourth ventricle, functional hearing improvement, surgical complications. RESULTS Two patients met indications and underwent surgery. There were no immediate or delayed surgical complications. Both had subtotal tumor removal with significant decompression of the brainstem and ABI placement. One patient achieved voice and environmental sound awareness at 35 to 55 dbHL across frequencies. The second patient presented with failure to thrive and multiple lower cranial neuropathies in addition to the above-listed indications. She was hospitalized multiple times after surgery due to failure to thrive and recurrent aspiration pneumonia. Her device was never activated, and she expired 1 year after surgery. CONCLUSIONS The xMCF with tentorial ligation is an additional approach for tumor resection and ABI placement in selected patients with neurofibromatosis type 2. Future studies will further define when this approach is most applicable as well as the challenges and pitfalls.

OBJECTIVE To determine the association between radiographic cerebrospinal fluid (CSF) cap in the lateral internal auditory canal (IAC) and likelihood of successful hearing preservation in middle cranial fossa (MCF) vestibular schwannoma (VS) surgery. STUDY DESIGN Retrospective chart review. SETTING Academic tertiary referral center. PATIENTS One hundred thirty-eight consecutive patients (mean age/standard deviation, SD, 50/11 yr) who underwent MCF VS resection. INTERVENTIONS MCF VS excision. MAIN OUTCOME MEASURES Size of fundal fluid cap on preoperative magnetic resonance imaging (MRI), pre- and postoperative pure-tone average (PTA), and word recognition score (WRS). RESULTS Mean tumor and fundal fluid sizes were 9.7 mm (SD, 3.9 mm) and 2.8 mm (SD, 1.7 mm), respectively. On bivariate analysis, fundal fluid size was associated with larger tumor size (p = 0.005) but not changes in postoperative PTA (p = 0.45) or WRS (p = 0.17). When fundal fluid size was stratified as none (

Aim The aim of this study is to present the middle fossa technique (MFT) as an alternative for patients who cannot undergo traditional surgery for active transcutaneous bone conduction implants (ATBCI) due to their altered anatomy or desire for future aesthetic reconstruction. Design A case series descriptive study was designed. The MFT was developed. Preoperative and postoperative information from 24 patients with external auditory canal atresia (EACA) and implanted with ATBCI was reviewed. Results A total of 24 children with bilateral EACA received implants in the middle cranial fossa. Their average age was 12. Of these patients, eight had an associated congenital disorder: Goldenhar Syndrome, Treacher Collins Syndrome or the Pierre Robin Sequence. The average follow-up was at 17 months (ranging from between 2- and 36 mo) and there were no major complications. Four patients showed skin erythema at the processor site after turn on, which was solved by lowering the magnet strength. One patient had a scalp hematoma that required puncture drainage. The hearing thresholds went down on average from 66.5 to 25.2 dB 1 month after turn on. Speech recognition improved respectively from 29.4% without and 78.9% with a bone conduction hearing aid to 96.4%. Conclusion MFT placement of the ATBCI was proven to be safe and effective and a viable option for treating pediatric patients with EACA who cannot receive implants at the sinodural angle or in the retrosigmoidal position because of their altered anatomy and/or desire for future aesthetic reconstruction.

Objective To analyze the immediate postoperative and long-term hearing outcome data in patients who have undergone hearing preservation attempts with the middle cranial fossa (MCF) approach for the resection of sporadic vestibular schwannoma. Study design Retrospective review of a surgical patient cohort. Setting Tertiary academic referral center. Patients Adult patients with unilateral sporadic vestibular schwannoma. Intervention Surgical treatment with a MCF approach. Main outcome measure Comparison of pre- and postoperative audiometric data in accordance with the 1995 and 2012 American Academy of Otolaryngology/Head and Neck Surgery guidelines on reporting hearing outcomes and with a word recognition score only scale. Long-term hearing outcome data were analyzed in the following postoperative groups: 3 to 5, 6 to 8, 9 to 11, and 12+ years after surgery. Results From 1999 to 2016, 174 patients underwent the MCF approach and 155 of them met inclusion criteria for analysis of hearing outcome data. Class A or B hearing was preserved in 70% of the entire cohort after recovery. Seventy-one patients with measurable hearing met criteria for long-term data analysis. The rate of American Academy of Otolaryngology/Head and Neck Surgery class A or B hearing preservation was 82% at 3 to 5 years and declined thereafter. The rate of word recognition score class I or II hearing preservation was 98% at 3 to 5 years and declined less rapidly thereafter. Patients with preoperative Class A hearing had significantly higher rates of successful hearing preservation at all postoperative intervals. Conclusion Delayed hearing loss occurs in a progressively increasing fashion but speech understanding remains durable for a majority of patients whose hearing is initially preserved with the MCF approach.

Hypothesis The temporal bone shows regional differences in bone development. Background The spreading pattern of acute mastoiditis shows age-related differences. In infants, it spreads laterally and causes retroauricular swelling, whereas in older children, it tends to spread medially and causes intracranial complications. We hypothesized that bone maturation may influence the spreading pattern of acute mastoiditis. Methods Eighty participants with normal hearing, aged 3 months to 42 years, participated in this study. Computed tomography (CT) values (Hounsfield unit [HU]) in various regions of the temporal bone, such as the otic capsule (OC), lateral surface of the mastoid cavity (LS), posterior cranial fossa (PCF), and middle cranial fossa (MCF), were measured as markers of bone density. Bone density development curves, wherein CT values were plotted against age, were created for each region. The age at which the CT value exceeded 1000 HU, which is used as an indicator of bone maturation, was calculated from the development curves and compared between the regions. Results The OC showed mature bone at birth, whereas the LS, PCF, and MCF showed rapid maturation in early childhood. However, there were significant regional differences in the ages of maturation: 1.7, 3.9, and 10.8 years for the LS, PCF, and MCF, respectively. Conclusion To our knowledge, this is the first report to show regional differences in the maturation of temporal bone, which could partly account for the differences in the spreading pattern of acute mastoiditis in individuals of different ages.

To determine the efficacy and morbidity of repairing spontaneous cerebrospinal fluid (CSF) leaks with the middle cranial fossa (MCF) approach without the use of a lumbar drain (LD), as perioperative use of LD remains controversial.Retrospective review from 2003 to 2015.University of Iowa Hospitals and Clinics and Indiana University Health Center.Those with a confirmed lateral skull base spontaneous CSF leaks and/or encephaloceles.MCF approach for repair of spontaneous CSF leak and/or encephalocele without the use of lumbar drain. Assessment of patient age, sex, body mass index (BMI), and medical comorbidities.Spontaneous CSF leak patient characteristics (age, sex, BMI, obstructive sleep apnea) were collected. Length of stay (LOS), hospital costs, postoperative complications, CSF leak rate, and need for LD were calculated.Sixty-five operative MCF repairs were performed for spontaneous CSF leaks on 60 patients (five had bilateral CSF leaks). CSF diversion with LD was used in 15 of 60 patients, mostly before 2010. After 2010, only three of 44 patients (6.7%) had postoperative otorrhea requiring LD. The use of LD resulted in significantly longer LOS (3.6 ± 1.6 versus 8.7 ± 2.9 d) and hospital costs ($29,621). There were no postoperative complications in 77% (50 of 65) of cases. Three cases required return to the operating room for complications including frontal subdural hematoma (1), subdural CSF collection (1), and tension pneumocephalus (1). No patients experienced long-term neurologic sequelae or long-term CSF leak recurrence with an average length of follow-up of 19.5 months (range 3-137 mo). The average patient BMI was 37.5 ± 8.6 kg/m. The average age was 57.5 ± 11.4 years and 68% were female. Obstructive sleep apnea was present in 43.3% (26 of 60) of patients.The morbidity of the MCF craniotomy for repair of spontaneous CSF leaks is low and the long-term efficacy of repair is high. Universal use of perioperative lumbar drain is not indicated and significantly increases length of stay and hospital costs. Obesity and obstructive sleep apnea are highly associated with spontaneous CSF leaks.

OBJECTIVE Demonstrate that an endoscopic keyhole approach to the middle cranial fossa is technically feasible for repair of semicircular canal dehiscence. STUDY DESIGN Cadaveric technical feasibility/methods development study. SETTING Tertiary care military medical center. PATIENTS Three fresh cadaveric heads (six sides). INTERVENTION(S) Endoscopic minimally invasive approach to the middle cranial fossa using the Medtronic Fusion Guidance system. MAIN OUTCOME MEASURE(S) Ability to identify the surgical landmarks of the middle cranial fossa and successfully identify and instrument the superior semicircular canal. RESULTS In every attempt, the arcuate eminence was successfully identified under endoscopic visualization and with the assistance of surgical navigation. The superior semicircular canal was unroofed, and its location confirmed visually and with the navigation system. The opened canal was then plugged with bone wax, bone pate, and covered with fascia. The 15-mm burr hole craniotomy provided ample room for one working instrument and a 4-mm 0-degree endoscope. CONCLUSION The endoscopic keyhole approach to superior semicircular canal dehiscence is technically feasible in a human cadaveric model. Further studies will determine 1) if this approach is possible and safe in vivo, 2) is associated with improved surgical outcomes, and 3) if surgical navigation aids in this approach.

OBJECTIVES To describe the use of a piezosurgery medical device to perform a craniotomy and produce a split calvarial graft for the repair of middle cranial fossa meningoencephaloceles. STUDY DESIGN Retrospective case review. SETTING Tertiary referral hospital. PATIENTS Ten consecutive patients undergoing middle cranial fossa approach for the repair of meningoencephaloceles. INTERVENTION Therapeutic. MAIN OUTCOME MEASURES Intraoperative and postoperative complications, success rate as defined by the ability to fashion a split calvarial graft that achieves complete closure of the tegmen defect. As a secondary outcome measure, evidence of integration of the split calvarial bone graft with the adjacent skull base was assessed. RESULTS There were no intraoperative or postoperative complications. An appropriately sized calvarial bone graft was produced, and complete closure of the tegmen defect was achieved in all 10 cases. Computed tomography demonstrated evidence of integration of the bone graft in eight cases between 4 and 9 months after surgery. CONCLUSION The piezosurgery medical device provides a safe and effective means by which the middle fossa craniotomy and split calvarial bone graft can be produced to repair defects of the middle fossa tegmen, with integration of the bone graft in the majority of cases.

Objective To review the clinical presentation, differential diagnosis, management strategy, and outcomes after microsurgical resection of cavernous hemangiomas (CHs) arising primarily within the internal auditory canal (IAC) and cerebellopontine angle (CPA). Patients Twelve patients (10 men; aged 18-66 yr) were included from 1982 to 2012 from one of two tertiary academic referral centers. Intervention(s) All patients underwent preoperative imaging evaluation and subsequent microsurgical resection. Main outcome measure(s) American Academy of Otolaryngology-Head and Neck Surgery hearing class, facial nerve function, and tumor control. Results The most common presenting symptoms were ipsilateral sensorineural hearing loss, nonpulsatile tinnitus, and vertigo. Three presented with facial paresis, 10 had lost serviceable hearing preoperatively. All lesions demonstrated heterogeneous enhancement with gadolinium and hyperintense signal on T2-weighted imaging. The median tumor diameter was 8 mm; eight CHs were confined to the IAC, whereas four involved the CPA. Tumors were accessed via a translabyrinthine approach in eight cases, retrosigmoid craniotomy in three cases, and a middle cranial fossa approach in one case. Ten patients received gross total resection, whereas two underwent subtotal removal. Neither patient with serviceable preoperative hearing retained useful hearing after resection. Eight of the nine patients with normal preoperative facial nerve function retained House-Brackmann grade 1 function after surgery. One patient had residual tumor treated with postoperative stereotactic radiosurgery. Conclusions Primary CHs of the IAC and CPA are rare and present clinically and radiographically similar to vestibular schwannoma. Microsurgical resection provides excellent facial nerve outcomes and tumor control for most patients; however, the majority of individuals will acquire non-serviceable hearing either from disease or as a result of treatment.

Objective To investigate the long-term patient outcomes after tumor debulking for internal auditory canal facial schwannoma (FNS). Study design Retrospective case review. Setting Tertiary referral center. Patients Patients operated on between 1998 and 2010 for a preoperative diagnosis of vestibular schwannoma with the intraoperative identification FNS instead. Intervention Diagnostic and therapeutic. Main outcome measures House-Brackmann facial nerve score immediately and at long-term follow-up (>1 yr); recurrence of tumor. Results Sixteen patients were identified who were presumed to have vestibular schwannoma but intraoperatively were diagnosed with facial nerve schwannoma. Eleven underwent debulking surgery (67%-99% tumor removal), 2 underwent decompression only, 2 were diagnosed with nervus intermedius tumors and had total tumor removal with preservation of the motor branch of cranial nerve VII, and 1 had complete tumor removal with facial nerve grafting. Five of 11 debulking patients underwent the middle cranial fossa approach for tumor removal; the remainder had translabyrinthine resections. One debulking patient was lost to follow-up. Nine of 10 patients with long-term follow-up had House-Brackmann Grade I or II facial function. One patient had recurrence of the tumor that required revision surgery with total removal and facial nerve grafting. Conclusion Tumor debulking for FNS provides an opportunity for tumor removal and excellent facial nerve function. Continuous facial nerve monitoring is vital for successful debulking surgery. FNS debulking is feasible via the middle cranial fossa approach. Serial postoperative imaging is warranted to monitor for recurrence.

Objectives To examine hearing preservation rates, facial nerve outcomes, and tumor recurrence rates in patients with neurofibromatosis Type 2 undergoing a primary middle cranial fossa approach for vestibular schwannoma removal. Study design Retrospective chart review. Setting Private practice tertiary neurotology referral center. Patients All patients with neurofibromatosis Type 2 undergoing attempted hearing preservation via a middle cranial fossa approach for removal of vestibular schwannoma from January 1, 2000, to June 1, 2010. Intervention Primary middle cranial fossa approach for removal of vestibular schwannoma. Main outcome measures Preoperative, postoperative, and change in hearing thresholds, word recognition scores, and American Academy of Otolaryngology-Head and Neck Surgery hearing class, House-Brackmann facial nerve grade, and tumor recurrence. Results Class A or B hearing according to the American Academy of Otolaryngology-Head and Neck Surgery was maintained in 50% of cases, whereas 63.6% had Class A, B, or C hearing, with an average word recognition score of 93.8% at an average follow-up period of 32.5 months. Facial nerve outcomes were excellent; 75% of cases maintained House-Brackmann Grade 1, whereas 94.3% had Grade 1 or 2 at an average of 25 months after surgery. Tumor growth within the surgical field was observed radiographically in 59% of cases. Conclusion In patients with neurofibromatosis Type 2, proactive treatment of smaller tumors provides a chance to maintain serviceable hearing and obtain tumor control for extended periods. When examining hearing outcomes, it is important to use word recognition scores, in addition to American Academy of Otolaryngology-Head and Neck Surgery hearing class, to better assess functionality. Although facial nerve outcomes tend to be favorable, the growth of new tumors, including facial schwannomas, may occur within the surgical field. Continued surveillance with serial magnetic resonance scans after surgery is mandatory.

Hypothesis: Cone beam volumetric tomography (CBVT) has better spatial resolution compared with multi slice computed tomography (MSCT) in temporal bone imaging for superior canal dehiscence (SCD). Background: Imaging of SCD has traditionally used MSCT, but the ability to resolve thin bone next to low-radiodensity brain and inner ear fluids at the interface of the superior canal (SC) with the middle cranial fossa can be adversely affected by partial volume averaging, errors in registration of successive slices, and other factors. CBVT may offer advantages in these regards and may have better spatial resolution for this application. Methods: Five cadaveric temporal bones were scanned using both CBVT and MSCT. The information content at the interface of the SC and the middle cranial fossa was measured for each method using spatial differential transformations. The ability of each method to resolve progressively smaller interfaces between bone and fluid was measured by creating a spatial grating model from a human temporal bone. Results: The information content and spatial resolution were superior for CBVT compared with MSCT. Conclusion: The gold standard for diagnosis of SCD has been MSCT, but CBVT may offer improvements in information content and spatial resolution at the interface of the SC and the middle cranial fossa.

Objectives To investigate the historical origins of the current middle fossa (MF) approach to the cerebellopontine angle (CPA). Methods A review of more than 30 original articles from the 1880 s to the early 1960s that document the evolution of the MF approach. Historically important journal articles and book chapters in various languages were supplemented by interviews with surgeons instrumental in the adaptation of this method to modern microsurgical neurotology. Results The inspiration for the current MF approach could be traced back to the late 19th century extradural subtemporal surgeries for the trigeminal neuralgia performed by Krause and Hartley and the contemporary surgeries performed by Ernst von Bergmenn for treatment of otogenic temporal bone infections. The first case of MF approach to CPA for vestibular nerve section was reported by RH Parry in 1904. In the mid-20th century, otologists found numerous applications for this approach, which gained popularity at the hands of William House. Although his initial MF operations aimed to decompress the internal auditory canal for cochlear otosclerosis, House soon realized the versatility of this approach and performed his first MF acoustic neuroma surgery in 1961. Conclusion The current MF approach has its roots in operations for trigeminal neuralgia and otologic surgeries for palliation of temporal bone infections performed in the late 19th century. The earliest reported MF approach to the CPA dates back to 1904 and its application to microsurgical exposure of the internal auditory canal to the late 1950s.

Objective Petrous apicitis and cranial base osteomyelitis are life-threatening conditions. A surgical management may be necessary in cases that progress, in conditions that fail to improve with medical treatment, or in cases with impending complications. In this study, we describe a technique to remove the maximum amount of infected temporal bone while preserving the integrity of the peripheral auditory pathway and facial nerve. Study design Retrospective study. Setting Tertiary referral hospital. Patients Five patients with impending complications, whose disease progressed or whose conditions failed to improve while on culture-directed antibiotics underwent circumferential petrosectomy. Interventions The circumferential petrosectomy removes most of the temporal bone around the external, middle, and inner ear. A combined retrolabyrinthine-apical petrosectomy is performed in conjunction with the fallopian bridge technique using a transmastoid and middle cranial fossa approach. A split temporalis muscle flap is used to bring vascularized tissue to the mastoid, jugular foramen, and petrous apex. Main outcome measures Disease resolution, change in hearing or facial nerve function, complications. Results Each of the five patients had modifications to the procedure tailored to their disease extent: three had disease primarily involving the petrous apex and two had disease adjacent to the jugular foramen. Additional cultures of the infected bone were obtained during surgery. A culture-directed antibiotic therapy (duration, 6-10 weeks) was administered after surgery, which resulted in the complete resolution of the disease and the associated symptoms in all five patients. No patient experienced hearing loss or facial nerve dysfunction as a result of the surgery within at least 1 year of follow-up in four of the five patients in this series. Conclusion The circumferential petrosectomy is a potential treatment option when medical treatment fails in patients with petrositis or cranial base osteomyelitis. It permits maximal temporal bone debridement while preserving hearing and facial nerve integrity in these life-threatening disease processes.

Objective: To highlight a case of cochlear implantation in the setting of ipsilateral petrous apex chondrosarcoma. Background: A patient with bilateral progressive hearing loss was incidentally found to have a destructive right petrous apex lesion on computed tomography before cochlear implantation. The patient had no associated symptoms and a magnetic resonance imaging scan was obtained, narrowing the differential diagnosis. A middle cranial fossa approach was performed for synchronous biopsy of the lesion and cochlear implantation. Results: Frozen sections revealed a low-grade chondroid lesion, and a Med-El Combi 40+ cochlear implant with a split electrode array was inserted via the middle fossa. Final pathologic examination revealed a Grade I chondrosarcoma. The patient suffered no complications postoperatively and was followed-up over 5years with serial computed tomographic scans and clinical examinations. No additional treatment was administered. Eighteen months postoperatively, the patient experienced episodic vertigo. There were no new findings on computed tomography, and the vertigo improved with a low-salt diet. Otherwise, the patient had excellent hearing results, and the lesion has not progressed under observation. Conclusion: The implications of observing low-grade chondrosarcomas in well-selected patients and the unique aspect of cochlear implantation on the affected side are discussed.

Objective To evaluate surgical results using the middle cranial fossa approach for hearing preservation vestibular schwannoma surgery. Study design Retrospective case review. Setting Tertiary referral academic center. Patients Seventy-three consecutive patients with vestibular schwannoma operated on using the middle cranial fossa approach between February 1999 and February 2005. Interventions The tumors were removed via the middle cranial fossa approach with modifications to improve exposure. Standard auditory brainstem and facial nerve monitoring were used. Main outcome measures Pre- and postoperative hearing measures and facial function, tumor size, and postoperative complications. Hearing status was categorized into Classes A, B, C, and D as described by the American Academy of Otolaryngology-Head and Heck Surgery "Guidelines for the Evaluation of Hearing Preservation in Acoustic Neuroma, 1995." Results Thirty-four patients presented with Class A hearing preoperatively. Among patients presenting with Class A hearing, a total of 27 (80%) maintained Class A or B hearing postoperatively. Of these, 21 (62%) remained in Class A, 6 (18%) deteriorated slightly to Class B, and 7 (20%) deteriorated to Class D postoperatively. Twenty-eight patients presented with Class B hearing preoperatively. Of these, 18 (64%) remained in Class B, 3 (11%) deteriorated to Class C, and 7 (25%) deteriorated to Class D. Three patients had Class C hearing preoperatively. Of these, 2 (66%) remained in Class C and 1 (33%) deteriorated to Class D. Eight patients presented in Class D and one of these improved to Class C postoperatively. Overall, 62 patients presented with useful (Class A or B) hearing and 45 (73%) remained in Class A or B. Nineteen patients had tumors larger than 10 mm in greatest dimension and had Class A or B hearing preoperatively. Of these, 11 (58%) retained Class A or B hearing postoperatively. At 4 months or greater follow-up, facial nerve outcome were excellent in 96%: House-Brackmann Grade I in 61 (85%), Grade II in 8 (11%), and Grade III in 3 (4%). There were no Grade IV, V, or VI results on final follow-up. Six (8%) patients developed cerebrospinal fluid leaks. Conclusion By achieving excellent exposure and using meticulous microsurgical technique, it is possible to resect small vestibular schwannomas via the middle fossa approach, with preservation of hearing at excellent or preoperative levels in the majority of patients, with excellent or satisfactory facial nerve outcomes in 96% of patients.

OBJECTIVE: The preoperative, intraoperative, and postoperative variables of patients experiencing hearing improvement after middle fossa resection of vestibular schwannomas were evaluated as potential prognostic indicators. STUDY DESIGN: Retrospective case review with new objective postoperative data collected on patients with documented hearing improvement. SETTING: California Ear Institute at Stanford and Stanford University Hospital, a tertiary referral center. PATIENTS: The patient group consisted of 30 consecutive patients undergoing middle fossa approach to vestibular schwannoma between October 24, 1994, and November 11, 1998. INTERVENTION: Hearing preservation surgery via the middle cranial fossa approach was performed on all patients. MAIN OUTCOME MEASURES: Pure-tone averages (PTAs) and speech discrimination scores (SDS) were used to document hearing preoperatively and postoperatively. Preoperative electrophysiologic studies of auditory brainstem response, electronystagmography, electrical neuronography, transient evoked otoacoustic emissions, and distortion product otoacoustic emissions were evaluated. Intraoperative continuous nerve action potential and auditory brainstem response tracings were reviewed. Postoperative auditory brainstem response and transient evoked otoacoustic emissions were obtained when possible on patients whose hearing improved. Statistical analysis was completed using Student's t test and chi-square test. RESULTS: Seventeen (57%) of 30 patients with tumors ranging from 2 to 31 mm maintained hearing postoperatively. Among patients with hearing preservation, 7 (41% or 23% of the overall group) exhibited hearing improvement (PTA 2 improved by > or =5 dB and/or SDS improved by > or =12%). Three of these 7 patients moved from nonfunctional (AAOHNS class C/D) to functional (AAOHNS class A/B) categories. All patients who enjoyed postoperative hearing improvement had preoperative absence or abnormality of ABRs. No patient with normal preoperative ABR experienced hearing improvement. Hearing improvement patients also had lower preoperative caloric function on electronystagmography compared with the entire group (p < 0.02) and were more likely to have superior vestibular nerve tumors. No differences were noted for electrical neurography and otoacoustic emissions. CONCLUSIONS: Middle fossa resection of vestibular schwannoma offers patients the possibility of hearing improvement after treatment. The chance of hearing improvement is significantly higher than with other forms of treatment such as radiation therapy or translabyrinthine surgery. Although preoperative ABR abnormality may be an indicator of poor prognosis for hearing preservation, those patients who enjoy hearing improvement come from the group of patients with abnormal preoperative ABRs. Other factors identified as associated with hearing improvement include poor SDS with more normal PTA 2, and significantly decreased electronystagmographic caloric function (as an indicator of superior vestibular nerve tumors). Hearing improvement to the functional range after surgical resection is possible in some patients previously thought to be poor candidates for hearing preservation attempts. Hearing improvement may continue for many months after surgery.