Assessment of Metabolic Markers and Osteoporosis in 250 Patients with Superior Semicircular Canal Dehiscence Treated With Middle Fossa Craniotomy.

BACKGROUND: Superior semicircular canal dehiscence (SSCD) is caused by bony defects in the osseous shell of the arcuate eminence separating the labyrinth and the intracranial space. This pathologic third window causes hydroacoustic transmission resulting in debilitating symptoms. We examine the pathophysiologic association between metabolic markers, previous medical history, and SSCD symptoms before and after middle fossa craniotomy (MFC) treatment. METHODS: This study was conducted between March 2011 and September 2020 with patients with SSCD who underwent MFC. We used a Fisher test to compare variables, including bilateral SSCD, second surgery, ear anomaly, osteoporosis, arthritis, vitamin D, and preoperative/postoperative symptoms, and others. Point-biserial correlation analysis was performed to test correlations between continuous variables and categorical variables. RESULTS: A total of 250 patients with SSCD underwent MFC repair. There was significant postoperative resolution in all symptoms (P < 0.0001). Laboratory 25-hydroxyvitamin D values correlated with preoperative aural fullness (rpb= 0.29; P = 0.03), and preoperative disequilibrium (rpb= -0.32; P = 0.02). Serum calcium values correlated with preoperative hearing loss (rpb= 0.16; P = 0.02). Osteoporosis history (n = 16; 6%) was more prevalent in female patients (P = 0.0001), associated with higher levels of preoperative hearing loss (odds ratio, 4.56; P = 0.02) and higher postoperative hearing loss resolution (odds ratio, 2.89; P = 0.0509). CONCLUSIONS: Certain metabolic markers may predict SSCD presentation before and after surgery. Previous history of osteoporosis, autoimmune conditions, or arthritis may play a role in SSCD pathophysiology and can help predict clinical outcomes. Future evaluation should take metabolic laboratory values and acquire an exact medical history.

Clinical Assessment of Patients with Bilateral Superior Semicircular Canal Dehiscence.

OBJECTIVE: Superior semicircular canal dehiscence (SSCD) is caused by a deformity in the arcuate eminence, leading to various vestibular and auditory symptoms that can manifest unilaterally or bilaterally. The aim of the present study was to distinguish the differences in symptoms, treatment options, and outcomes between patients with unilateral and bilateral SSCD. METHODS: A retrospective medical record analysis was conducted to identify patients with SSCD treated at a tertiary care center from March 2011 to May 2017. The patient demographic data, preoperative symptom presentation, and postoperative outcomes were extracted. Statistical analyses were performed using IBM SPSS Statistics. Fisher's exact tests were computed to investigate the relationships between binary variables, with a significance level of P < 0.05. RESULTS: A total of 99 patients with SSCD had been treated at our institution from March 2011 to May 2017. Of these 99 patients, 41 (41.4%) had a diagnosis of bilateral SSCD. Of the 41 patients with bilateral SSCD, 27 (65.9%) were women, and the mean age was 53.6 ± 10.9 years (range, 31.7-73.9). The most common presenting symptom was tinnitus (n = 33; 80.4%) and dizziness (n = 33; 80.4%). Previous trauma to the head correlated with a bilateral SSCD presentation (P = 0.04). Trends were reported between female sex and bilateral SSCD [r(35) = 0.32379; P = 0.0506]. Postoperatively, trends were also found, with greater rates of dizziness in patients with bilateral SSCD compared with those with unilateral SSCD (odds ratio, 3.81; P = 0.0659), and less improvement in dizziness (odds ratio, 0.186; P = 0.0627). No other significant differences were found between the symptoms or clinical outcomes and improvements between the bilateral and unilateral cohorts. CONCLUSION: Bilateral SSCD might result in different clinical symptoms that are more prevalent compared with unilateral SSCD. The findings from the present series of patients with bilateral SSCD suggest that patient symptoms and history are important in the diagnosis of bilateral SSCD and deciding whether 1 or both dehiscences requires surgical intervention.

The Predictability Precision of Superior Semicircular Canal Through Radiological Assessment and Microanatomical Dissection.

OBJECTIVE: There is still ongoing research on the relationship of arcuate eminence (AE) and superior semicircular canal (SSC). We aimed to evaluate the precision of predictability of SSC through the morphology of AE via radiological means. MATERIALS AND METHODS: This investigation is performed on 12 dry skulls belonging to Mersin University Medical Faculty department of anatomy. Computed tomography (CT) assessment is performed with 0.5-mm-thin sections temporal bone algorithm on dry skulls which were marked with fixated copper wire by scotch tapes on the most prominent part of the middle fossa floor assuming the location of AE. The data are reformatted on the workstation with vitrea 2.0. The distances of the determined three points including lateral (A), apical (B), and medial (C) of the SSC and the copper wire are measured radiologically. Also, the height between the most apical part of the SSC to the floor of the skullbase (H) is measured. The angles between the placed copper wires and the SSC (E) are calculated. The angle between SSC and the midpoint of the IAC (F) and SSC to the sulcus of the greater GSPN (G) were measured. The nearest distance was measured between the most posterior part of the SSC and the point marked by the perpendicular line drawn from the medial border of the petrous bone to the most posterior part of the internal auditory canal (IAC) (D). RESULTS: The right and left A, B, and C distances are 2.54+/- 2.75, 3.67+/-3.16, 5.85+/-3.77; 2.92+/-2.24, 3.68+/-2.93, 6.09+/-3.40, respectively. We could not find any statistical significance when the right A, B, and C distances were compared with the left values. Examination of the values revealed that C distance is greater than the A distance of the same side both for right (p=0.040) and left (p=0.022) measurements. The calculated left and right E angles are 30.313+/-12.838, and 35.558+/-18.437 degrees, respectively. Statistical significance was not found between the right and left angles. The right and left F, G angles were 53.17, 47.25; 93.58, 100.92 degrees; and D distances are 8.01, 8.13 millimeters, respectively. Statistical significance was not found when right and left E, F, G angles and D distances were compared. Among 12 left and 12 right sides, the copper wire was found to be nearly overlapping to SSC in two in the right and only one in the left. CONCLUSION: This study reveals that there is a great variability predicting the exact location of SSC through the prominence of AE. Complementary studies are needed with greater number of dry skulls and cadavers. Comparison of different hypothesis including the effect of temporal lobe sulcus is to be discussed to better enlighten the exact relationship of the aforementioned anatomical structures.

Retrosigmoid versus translabyrinthine approach to acoustic neuroma resection: A comparative cost-effectiveness analysis.

OBJECTIVES/HYPOTHESIS: Approach-specific economic data of acoustic neuroma (AN) resection is lacking. The purpose of this study was to analyze and compare adjusted total hospital costs, hospital and intensive care unit (ICU) length of stay (LOS), and associated factors in AN patients undergoing resection by translabyrinthine (TL) approach versus retrosigmoid (RS) approach. STUDY DESIGN: Retrospective chart review. METHODS: A total of 113 patients with AN undergoing TL (N = 43) or RS (N = 70) surgical resection between 1999 and 2012 were analyzed. Data including age, health status, preoperative hearing, tumor size, postoperative complications, hospital, ICU LOS, and disposition after discharge were collected from medical records and compared between both groups. Cost data was obtained from the hospital finance department and adjusted based on the Consumer Price Index for 2013. RESULTS: There were no significant differences in demographic data, preoperative hearing, preoperative health status, or postoperative complication rate. Total hospital LOS and ICU LOS were significantly longer in the RS compared to the TL group (4.3 ± 3.6 vs. 2.6 ± 1.1 days; P < 0.001, and 1.5 ± 1.1 vs. 1.0 ± 0.5 days; P = 0.015, respectively). Tumors were larger in RS compared to the TL group (2.1 ± 1.0 cm vs. 1.5 ± 0.7 cm, respectively; P = 0.002). When patients were stratified by tumor size < or ≥ 2 cm, the total hospital LOS remained greater in the RS group in both subgroups (< and ≥ 2 cm, P < 0.001, and P = 0.031, respectively). However, there was no difference in the total ICU LOS between both subgroups. The adjusted mean total hospital cost was higher in the RS compared to the TL group ($25,069 ± 14,968 vs. $16,799 ± 5,724; P < 0.001). The adjusted mean total hospital cost was greater in the RS group with tumor < 2 cm (P < 0.001) but not significantly different in patients with tumors ≥ 2 cm. Univariate analysis showed that greater tumor size, poorer preoperative health status, the presence of major postoperative complications, and the RS approach were independently significantly associated with higher total hospital LOS (P = 0.001, P = 0.009, P = 0.001, and P < 0.001, respectively) and a higher adjusted total hospital cost (P < 0.001, P = 0.002, P = 0.014, and P < 0.001, respectively). CONCLUSION: Hospital LOS and total adjusted costs are significantly less for patients undergoing translabyrinthine acoustic neuroma resection compared to the retrosigmoid approach. Many factors appear to influence these differences. Economic considerations in addition to tumor characteristics and surgeon preference should be considered in future acoustic neuroma resections. LEVEL OF EVIDENCE: 2c.

Pressure assessment of superior semicircular canal dehiscence repair techniques--a temporal bone study.

OBJECTIVE: To develop a cadaveric temporal bone preparation to compare the strength of superior semicircular canal dehiscence (SCD) repair techniques. BACKGROUND: Superior semicircular canal dehiscence syndrome is a clinical condition with a variety of auditory and vestibular symptoms resulting from a mobile third window into the inner ear. Patients with incapacitating symptoms often undergo surgical repair. There have been no previous studies to directly assess the strength of techniques used for repair of SCD. METHODS: The ability of repair techniques to withstand prolonged pressure application was measured in prepared temporal bones (n = 5). Pressure changes were compared with the superior semicircular canal intact and with the dehiscence repaired via three repair techniques (resurfacing, plugging, and combined plugging and resurfacing). RESULTS: Each of the three repair techniques resisted loss of applied pressure as well as the closed system before creation of the dehiscence at pressures comparable to high-normal intracranial pressure (23-25 cm H2O). At supra-physiologic pressure levels (45-55 cm H2O), the combined plugging and resurfacing technique showed consistent resistance to loss of pressure as compared to instances of failure with either of the single repair approaches. CONCLUSION: Findings from the cadaveric temporal bone preparations revealed that even immediately after repair, each of the three main techniques are equally resistant to the application of high-normal intracranial pressure levels. However, with consistent resistance to loss of pressure across all trials, the combined plugging and resurfacing technique may offer improved resistance in instances where supra-physiologic pressures are encountered.

Face validity study of an artificial temporal bone for simulation surgery.

HYPOTHESIS: Using the rapid prototype (RP) technology, a physical construct of a human temporal bone was developed based on cadaveric tissue to permit simulated surgical training. The objective of the study was to test the face validity of the model. BACKGROUND: The cost and access to human cadaveric temporal bones is becoming increasingly challenging, particularly if there are religious and regulatory restrictions. There is a need to develop alternative strategies to improve accessibility. METHODS: Ultra high-resolution computed tomography (CT) images (0.15-mm resolution) were obtained from a cadaver temporal bone. Manual segmentation and conversion into a stereolithography file format permitted printing on a RP stereolithography printer. A 3-dimensional physical model was hardened to achieve the desired consistency. Eight practicing otologists were recruited to evaluate this model. Respondents were asked to drill the artificial bone and complete a rating survey upon completion. RESULTS: In using a Likert scale between 1 and 5, results for anatomic accuracy were favorable, with the best scores for overall morphology (4.63) and for lateral structures within the bone (4.5). The poorest scores were for the semicircular canals (3.75) and chorda tympani (3.25). Scores for haptic realism were good as well. The average score for the question "overall, how valuable is the model as a surgical simulator" was 4.1. The experts felt that junior residents (PGY 1-3) would benefit most from this surgical education model. CONCLUSION: The outer structures of the RP artificial temporal bone can be considered to have face validity. Improvements will continue to be made to address some of the deficiencies in the anatomic and haptic realism of this model.

Efficacy assessment and complications of surgical management for superior semicircular canal dehiscence: a meta-analysis of published interventional studies.

Superior semicircular canal syndrome (SSCS) includes vestibular and audiological symptoms which result from the introduction of a third mobile window into the osseous cochlea. Surgical repair is considered in cases of incapacitating symptoms. The present paper aims at comparing the different surgical approaches and modes of dehiscence repair, regarding their respective efficacy and potential pitfalls. A systematic literature review and meta-analysis of pooled data were performed. Study selection included prospective- and retrospective-controlled studies, prospective- and retrospective-cohort studies, ex vivo studies, animal models, case-reports, systematic reviews and clinical guidelines. A total of 64 primary operations for SSC repair were identified; 56 ears were operated for vestibular and 7 for auditory complaints. A total of 33 ears underwent canal plugging, 16 resurfacing, and 15 capping. Success rates were 32/33, 8/16, and 14/15, respectively. The observed differences were statistically significant (P=0.001). Resurfacing proved less effective than both plugging (P=0.002), and capping (P=0.01) techniques. Temporalis fascia was commonly used as sealing material and was combined with bone-pâté/bone-wax (plugging), bone-graft (resurfacing), or hydroxyapatite-cement (capping). Most operations were performed via middle-fossa approach; higher success rates were associated with plugging and capping techniques. SNHL and disequilibrium were the most frequent complications encountered. Most cases were followed for 3-6 months. Precise criteria regarding follow-up duration and objective success measures are not determined. Surgical repair of SSCS is considered as a valid therapeutic option for patients with debilitating symptoms. Consensus regarding strict follow-up criteria and objective assessment of success is necessary before larger scale operations can be implemented in clinical practice.

Assessment of the anatomical relationship between the arcuate eminence and superior semicircular canal by computed tomography.

The anatomical relationship between the arcuate eminence (AE) and the superior semicircular canal (SSC) was examined by computed tomography (CT) in 52 petrous bones of 26 patients. After acquiring volume data by multidetector CT, 1-mm thick oblique bone window images perpendicular to the SSC were obtained from the axial images. The distances between the AE and the SSC, and the SSC and the superior surface of the petrous bone were measured. The AE corresponded exactly with the SSC in only 2/52 petrous bones, and corresponded well in 7/52. The AE was lateral to the SSC in 25/52 cases, medial to the SSC in 6/52 cases, intersected in 3/52 cases, and was indiscernible in 9/52 cases. The distance between the SSC and the petrous surface was 0 mm in 45/52 petrous bones, 1 mm in 5/52, 2 mm in 1/52, and 3 mm in 1/52. The SSC typically does not correspond exactly with the AE, and is generally located just under the surface of the petrous bone. Planning of the middle cranial fossa approach requires location of the SSC by CT.