Educational simulator for mastoidectomy considering mechanical properties using 3D printing and its usability evaluation.

Complex temporal bone anatomy complicates operations; thus, surgeons must engage in practice to mitigate risks, improving patient safety and outcomes. However, existing training methods often involve prohibitive costs and ethical problems. Therefore, we developed an educational mastoidectomy simulator, considering mechanical properties using 3D printing. The mastoidectomy simulator was modeled on computed tomography images of a patient undergoing a mastoidectomy. Infill was modeled for each anatomical part to provide a realistic drilling sensation. Bone and other anatomies appear in assorted colors to enhance the simulator's educational utility. The mechanical properties of the simulator were evaluated by measuring the screw insertion torque for infill specimens and cadaveric temporal bones and investigating its usability with a five-point Likert-scale questionnaire completed by five otolaryngologists. The maximum insertion torque values of the sigmoid sinus, tegmen, and semicircular canal were 1.08 ± 0.62, 0.44 ± 0.42, and 1.54 ± 0.43 N mm, displaying similar-strength infill specimens of 40%, 30%, and 50%. Otolaryngologists evaluated the quality and usability at 4.25 ± 0.81 and 4.53 ± 0.62. The mastoidectomy simulator could provide realistic bone drilling feedback for educational mastoidectomy training while reinforcing skills and comprehension of anatomical structures.

Comparison of the 3D-Exoscope and Operating Microscope in Mastoidectomy.

OBJECTIVES: The operating microscope (OM) commonly used in ear surgeries has several disadvantages, including a low depth of field, a narrow field of view, and unfavorable ergonomic characteristics. The exoscope (EX) was developed to overcome these disadvantages. Herein, we compared OM and EX during mastoidectomy and found out the feasibility of the EX. STUDY DESIGN: Prospective randomized comparative study. SETTING: Tertiary academic medical center. PATIENTS: Patients who had mastoidectomy for chronic otitis media with or without cholesteatoma between January 2022 and April 2022. INTERVENTION: Canal wall-up mastoidectomy (CWUM) or canal wall-down mastoidectomy (CWDM) using OM or EX without endoscope. MAIN OUTCOME MEASURES: Operative setting time (the time between the end of general anesthesia and incision), operative time (from incision to suture), postoperative audiologic outcomes, perioperative complications, and the decision to switch from EX to OM. RESULTS: Of 24 patients who were diagnosed with chronic otitis media or cholesteatoma, 12 each were randomly assigned to the OM or EX group. The mean operation time was 175 ± 26.5 minutes and 172 ± 34.6 minutes in the EX and OM group, respectively, which was not significantly different ( p = 0.843). The procedures in the EX group were successfully completed using a three-dimensional (3D)-EX without conversion to OM. All surgeries were completed without any complications. The postoperative difference in the air and bone conduction was 11.2 and 12.4 dB in the EX and OM groups, respectively, which was not significantly different ( p = 0.551). CONCLUSIONS: EX is comparable to OM in terms of surgical time, complications, and audiologic outcomes following mastoidectomy. The EX system is a potential alternative to OM. However, further improvements are required to overcome some drawbacks (deterioration of image resolution at high magnification, requirement of an additional controller for refocusing).

Radioclinical Assessment of Posterior Tympanotomy Difficulties during Ordinary Cochlear Implantation: A Prospective Case-Series Study.

OBJECTIVES: This study proposes a preoperative radiologic scoring system for predicting posterior tympanotomy (PT) and mastoidectomy-associated difficulties during cochlear implantation (CI). STUDY DESIGN: It was a prospective case-series study. SETTINGS: The included CI surgeries were performed at tertiary referral institutions from October 2022 to April 2023. SUBJECTS: We included 73 CI candidates performed via the PT approach. INTERVENTION: The proposed radiologic score, composed of 13 items, was fulfilled and evaluated before each CI surgery. MAIN OUTCOME MEASURE: We correlated this score with the intraoperative difficulty and surgical duration. RESULTS: The operation was straightforward in 42 patients with a score of 3.87 ± 1.72 and challenging in 31 patients with a score of 10.66 ± 1.73. The radiologic score was strongly correlated with the surgical difficulty and duration (p < 0.0001). CONCLUSIONS: Our proposed radiologic score was a valid, reliable, and precise tool to predict intraoperative difficulty during cochlear implantation. Chorda-facial angle was the strongest predictor, significantly affecting the difficulty, surgical duration, and preoperative radiologic score. A score equal to or more than 7.5 was expected to be associated with surgical difficulty.

A Novel Technique of Reduction Meatoplasty for Correction of Very Large Meatus from a Previous Canal Wall-Down Mastoidectomy.

OBJECTIVE: To evaluate the efficacy of reduction meatoplasty, a novel technique aiming to improve the usage of molded hearing aids and ear plugs in patients undergoing mastoid obliteration of a previous canal wall-down (CWD) mastoidectomy, complicated with a very large meatus. PATIENTS: Twenty-six patients from a tertiary care neurotology clinic with a very large meatus from a previous CWD mastoidectomy, who were unable to use molded hearing aids or ear plugs for water protection. INTERVENTION: Reduction meatoplasty after mastoid obliteration (cartilage strips and bone pate) of the CWD mastoidectomy. The procedure involves removing a wedge of skin and underlying soft tissue superiorly in the meatus. MAIN OUTCOME MEASURES: Reduction in meatus size, enabling usage of hearing aids and ear plugs. RESULTS: Twenty-six patients underwent mastoid obliteration and reduction meatoplasty to reduce meatus size. Patients were followed up for an average of 22 months postoperation. After operation, the meatus size was significantly reduced in all patients, enabling usage of over-the-counter ear plugs. In addition, all six patients with hearing aids could use standard occlusive hearing aid domes without requiring molded hearing aids. No patients showed symptoms of chronic infection in the mastoid cavity during the follow-up period. CONCLUSIONS: Results of reduction meatoplasty showed significant improvements in functionality of the external auditory meatus, indicating that this technique is effective in reducing meatus size and improving the normal meatal anatomy after mastoid obliteration.

150 years ago: Schwartze's 1873 mastoidectomy and its implementation over the following 2 years.

BACKGROUND: In 1873, Hermann Schwartze and Adolf Eysell described a new surgical technique for treating mastoid disease using a mallet, chisels, and gouges of various sizes instead of trephines or drill instruments also called "modern mastoidectomy." On the 150th jubilee of this landmark article, we pay tribute by studying the reception and implementation of mastoidectomy in the 2 years following its publication. METHODS: The commentaries published in the otological and medical literature between the second part of 1873 to the end of 1875 were studied with an emphasis on the three specialized otological journals and the otological textbooks that existed during this period. RESULTS AND CONCLUSION: The princeps paper Ueber die künstliche Eröffnung des Warzenfortsatzes ("On the artificial opening of the mastoid process") by Hermann Schwartze and Adolf Eysell published in 1873 was rapidly disseminated in the medical literature for nearly 1 year, and then entered a phase of evaluation followed by a phase of extension and implementation, before finding its definitive place in the history of mastoid process surgery.

Impact of virtual reality training on mastoidectomy performance: a prospective randomised study.

PURPOSE: The opportunities for surgical training and practice in the operating room are in decline due to limited resources, increased efficiency demands, growing complexity of the cases, and concerns for patient safety. Virtual reality (VR) offers a novel opportunity to enhance surgical training and provide complementary three-dimensional experience that has been usually available in the operating room. Since VR allows viewing and manipulation of realistic 3D models, the VR environment could enhance anatomical and topographical knowledge, in particular. In this study, we explored whether incorporating VR anatomy training improves novices' performance during mastoidectomy over traditional methods. METHODS: Thirty medical students were randomized into two groups and taught mastoidectomy in a structured manner. One group utilized a VR temporal bone model during the training while the other group used more traditional materials such as anatomy books. After the training, all participants completed a mastoidectomy on a 3D-printed temporal bone model under expert supervision. Performance during the mastoidectomy was evaluated with multiple metrics and feedback regarding the two training methods was gathered from the participants. RESULTS: The VR training method was rated better by the participants, and they also needed less guidance during the mastoidectomy. There were no significant differences in operational time, the occurrence of injuries, self-assessment scores, and the surgical outcome between the two groups. CONCLUSION: Our results support the utilization of VR training in complete novices as it has higher trainee satisfaction and leads to at least as good results as the more traditional methods.

Comparison between classic 'Fisch' and 'corner-tag' meatoplasty techniques after canal wall down tympanomastoidectomy.

PURPOSE: To compare outcomes of two different methods of meatoplasty following Canal Wall-Down tympanomastoidectomy. METHODS: A retrospective case review study of 48 patients with non-complicated unsafe chronic suppurative otitis media candidate for post-auricular canal wall-down tympanomastoidectomy via a post-auricular approach at Otolaryngology department, Benha university hospitals from January 2021 to January 2023, all were operated for the first time, and divided into 2 groups each of 24 patients. Group A submitted for classic 'Fisch', and group B 'Corner-Tag' meatoplasty. RESULTS: The mean age was 28.88 ± 13.26 years in group A and 33.33 ± 16.04 years in group B. Only one patient (4.2 %) in each group developed wound infection and none in both groups developed perichondritis. Two patients (8.3 %) in group B compared to only one patient (4.2 %) in group A had granulations on the meatal incision. One patient (4.2 % of group A) needed revision meatoplasty. Group B needed more time for epithelization (mean 7.33 ± 0.96 weeks) than group A (mean 6.5 ± 0.88 weeks; P = 0.003*) also resulted in wider mean new meatus in group B (mean 10.50 ± 1.02 mm) than in group A (mean 9.63 ± 1.41 mm; P = 0.02*). CONCLUSION: Both techniques had comparable post-operative complications. 'Corner-Tag' technique needed more time for healing and epithelization but gave a wider new meatal diameter than 'Fisch' meatoplasty after one year of follow-up.

Quality of life after revision mastoidectomy with mastoid obliteration / Calidad de la vida después mastoidectomia de revisión con obliteración mastoidea

Aims To evaluate the postoperative quality of life (QoL) after revision canal wall down mastoidectomy with mastoid obliteration (rCWD). Material and methods A retrospective analysis was conducted on patients treated by rCWD for cholesteatoma between 2016 and 2019. A control group including all patients treated by primary canal wall down with mastoid obliteration (pCWD) for cholesteatoma between 2009 and 2014 was used for the comparison of the postoperative QoL, assessed by the COMQ-12. Results The rCWD and pCWD groups respectively counted 38 and 78 patients with an average follow-up of 30 and 62 months respectively. No significant difference was found in terms of QoL between the two groups. An intra-group analysis among rCWD patients, showed that patients treated by canal wall down (CWD) at the primary surgery had a significantly worse post-revision QoL compared to those initially treated by canal wall up (CWU), specifically in the hearing and balance domains of the questionnaire. Conclusions Revision mastoid obliteration leads to similar QoL results to those obtained after primary CWD with obliteration. Patients who had undergone a CWD as primary surgery complain worse hearing and balance problems compared to those primarily submitted to CWU, even after revision surgery. (AU)

Objetivo Evaluar la calidad de la vida (CdV) post-operatoria después de mastoidectomia de revisión con obliteración mastoidea y timpanoplastia abierta. Materiales y métodos Ha sido efectuada una análisis retrospectiva in pacientes afectados por colesteatoma y tratados con mastoidectomia de revision con obliteración mastoidea entre el 2016 y el 2019. Pacientes afectados por colesteatoma y tratados con timpanoplastia abierta primaria con obliteración mastoidea entre el 2009 y el 2014 representan el grupo de control. La CdV post-operatoria ha sido analizada con el cuestionario COMQ-12. Resultados El grupo de estudio y el grupo control cuentan respectivamente 38 y 78 pacientes con un seguimiento medio de 30 y 62 meses. La CdV no era significativamente diferente entre los dos grupos. Una sub-análisis en el grupo de estudio ha demostrado que la CdV era significativamente peor en pacientes primitivamente tratados con timpanoplastia abierta en comparación con pacientes primitivamente tratados con timpanoplastia serrada, en particular en los dominios de la audición y del equilibrio. Conclusiones La CdV obtenida después de la obliteración mastoidea de revisión es comparable a aquella obtenida con timpanoplastia abierta primaria con obliteración mastoidea. Los pacientes sometidos a cirugía de revisión que habían sido tratados con timpanoplastia abierta primaria presentan una CdV peor de los pacientes precedentemente tratados por timpanoplastia cerrada en los dominios de la audición y del equilibrio. (AU)

Canal wall up versus canal wall down mastoidectomy techniques in the pediatric population with cholesteatoma: A systematic review and meta-analysis of comparative studies.

IMPORTANCE: The optimal surgical management of cholesteatoma remains controversial. Within pediatric otolaryngology, one of the most vital points of contention is the selection of canal wall-up (CWU) versus canal wall-down (CWD) procedures. Pediatric cholesteatoma has high rates of recurrence (16%-54%). In adults, there is evidence that the selection of surgical techniques affects recurrence rates. This has not been shown in children. OBJECTIVES: 1. To systematically review the literature on recurrent and residual cholesteatoma after CWU and CWD in children and perform a meta-analysis of the data. 2. To assess the rates of recurrent and residual cholesteatoma between CWU and CWD techniques in pediatric patients. 3. To assess hearing outcomes by evaluating postoperative differences in the air-bone gap (ABG) between CWU and CWD techniques. DATA SOURCES: A systematic search of PubMed, Embase, Scopus, and Cochrane Collaboration was performed from inception to May 1st, 2020, to identify studies that compared CWU and CWD procedures for acquired cholesteatoma in children. STUDY SELECTION: Search records were screened in duplicate by four reviewers. Inclusion criteria consisted of comparative randomized clinical trials and observational studies assessing outcomes of CWU and CWD techniques in the pediatric population. Studies involving patients with congenital cholesteatoma were excluded. DATA EXTRACTION AND SYNTHESIS: Four reviewers working independently and in duplicate systematically reviewed and extracted study data. Dichotomous variables were analyzed as risk ratios (RR), while continuous variables were compared using weighted mean differences (MD). The risk of bias was assessed using the CLARITY Scale. PRIMARY OUTCOMES AND MEASURES: The outcomes were recurrence, residual disease, air-bone gap (ABG), and air conductive (AC) thresholds. RESULTS: After screening 1036 publications, 17 retrospective cohort studies were selected. 1333 children were included; the overall mean age was ten years (SD 7.9), and the overall mean follow-up time was 5.9 years (SD 6.6). CWU and CWD techniques were performed in 60% (796) and 40% (537) cases. We did not find differences in cholesteatoma recurrence (RR: 1.50, 95% CI 0.94; 2.40; n = 544; I2 0%; Tau [2]: 0.00), or rates of residual cholesteatoma (RR 1.51, 95% CI 0.96; 2.38, n = 506; I2: 0%; Tau [2]: 0.00) in patients who underwent CWU and CWD mastoidectomy. The mean air-bone gap was lower with CWU than CWD (mean difference: 7.60, 95% CI -10.65; -4.54; n = 242; I2: 71%; Tau [2]: 5.98). CONCLUSION: and relevance: We show similar rates of recurrence and residual disease after either CWU or CWD tympanoplasty. Our results challenge the fundamental principle of CWD surgery as a standard technique, as there is no difference in rates of recurrence and residual disease in CWU and CWD. Moreover, audiometric results support CWU with improved hearing outcomes. TRIAL REGISTRATION: PROSPERO identifier: CRD42020184029.

Prediction of Hearing Prognosis After Intact Canal Wall Mastoidectomy With Tympanoplasty Using Artificial Intelligence.

OBJECTIVE: To evaluate the performance of a machine learning model and the effects of major prognostic factors on hearing outcomes following intact canal wall (ICW) mastoidectomy with tympanoplasty. STUDY DESIGN: Retrospective cross-sectional study. SETTING: Tertiary hospital. METHODS: A total of 484 patients with chronic otitis media who underwent ICW tympanomastoidectomy between January 2007 and December 2020 were included in this study. Successful hearing outcomes were defined by a postoperative air-bone gap (ABG) of ≤20 dB and preoperative air conduction (AC)-postoperative AC value of ≥15 dB according to the Korean Otological Society guidelines for outcome reporting after chronic otitis media surgery. The light gradient boosting machine (LightGBM) and multilayer perceptron (MLP) models were tested as artificial intelligence models and compared using logistic regression. The main outcome assessed was the successful hearing outcome after surgery, measured using the area under the receiver operating characteristic curve (AUROC). RESULTS: In the analysis using the postoperative ABG criterion, the LightGBM exhibited a significantly higher AUROC compared to those of the baseline model (mean, 0.811). According to the difference between preoperative and postoperative AC, the MLP showed a significantly higher AUROC than those of the baseline model (mean, 0.795). CONCLUSION: This study analyzed multiple factors that could affect the hearing outcome using different artificial intelligence models and found that preoperative hearing status was the most important factor. Our findings provide additional information regarding postoperative hearing for clinicians.

Evolving microbial patterns of acute mastoiditis in pediatric patients undergoing mastoidectomy.

OBJECTIVE: To investigate the microbial patterns and clinical outcomes of pediatric patients undergoing mastoidectomy for acute coalescent mastoiditis and to identify factors associated with poor outcomes and/or prolonged treatment. STUDY DESIGN: Monocentric retrospective cohort study. SETTING: Tertiary referral pediatric hospital in Indiana. METHODS: By cross-referencing database data from the Pediatric Health Information System (PHIS) querying for all inpatient stays (patients younger than eighteen) with a diagnostic code of mastoiditis between January 1st, 2010 and August 31, 2019, and the electronic health record (Cerner) for Riley Hospital for Children, 46 patients with mastoidectomy were included. A two-tailed T-test was used to evaluate continuous parametric data. Statistical significance was determined as P < 0.05. For continuous variables, data was analyzed using continuous logistic regression. A criteria of p > 0.1 was used for inclusion in the multivariate regression. RESULTS: Inclusion criteria was met by 46 patients. From 2010 to 2019, S. pyogenes and S. pneumoniae were the most common bacteria, each isolated in 11 of 42 bacterial isolates (26.2%). There was no growth in 35.4% (17/48) of intra-operative wound cultures. On univariate analysis, patients with negative cultures had longer length of hospital stay (LOS) (7.7 days [6.5] vs. 4.3 [2.8]; p = 0.018) as well as higher rates of PICC (peripherally inserted central catheter) placement (53.3% vs. 19.4%; p = 0.021). There was a statistically significant difference in terms of gender (p = 0.021), with 15 males and 16 females in the positive culture cohort and 13 males and 2 females in the negative culture cohort. On multivariate analysis, which included gender, PICC placement, both intracranial and extracranial complications, duration of antibiotics, and LOS, female gender was the only significant predictor of positive culture status (p = 0.039). CONCLUSION: S. pyogenes and S. pneumoniae were the predominant etiologic agents in acute coalescent mastoiditis between 2010 and 2019, and negative wound cultures were associated with worse clinical outcomes.

3-D-Printed Models for Temporal Bone Training: A Validity Study.

OBJECTIVE: 3-D printing offers convenient and low-cost mastoidectomy training; nonetheless, training benefits using 3-D-printed temporal bones remain largely unexplored. In this study, we have collected validity evidence for a low-cost, 3-D-printed temporal bone for mastoidectomy training and established a credible pass/fail score for performance on the model. STUDY DESIGN: A prospective educational study gathering validity evidence using Messick's validity framework. SETTING: Seven Danish otorhinolaryngology training institutions. PARTICIPANTS: Eighteen otorhinolaryngology residents (novices) and 11 experienced otosurgeons (experts). INTERVENTION: Residents and experienced otosurgeons each performed two to three anatomical mastoidectomies on a low-cost, 3-D-printed temporal bone model produced in-house. After drilling, mastoidectomy performances were rated by three blinded experts using a 25-item modified Welling scale (WS). MAIN OUTCOME MEASURE: Validity evidence using Messick's framework including reliability assessment applying both classical test theory and Generalizability theory. RESULTS: Novices achieved a mean score of 13.9 points; experienced otosurgeons achieved 23.2 points. Using the contrasting groups method, we established a 21/25-point pass/fail level. The Generalizability coefficient was 0.91, and 75% of the score variance was attributable to participant performance, indicating a high level of assessment reliability. Subsequent D studies revealed that two raters rating one performance or one rater rating two performances were sufficiently reliable for high-stakes assessment. CONCLUSION: Validity evidence supports using a low-cost, 3-D-printed model for mastoidectomy training. The model can be printed in-house using consumer-grade 3-D printers and serves as an additional training tool in the temporal bone curriculum. For competency-based training, we established a cut-off score of 21 of 25 WS points using the contrasting groups method.

Comparison of Postoperative Nausea and Vomiting Incidence between Remimazolam and Sevoflurane in Tympanoplasty with Mastoidectomy: A Single-Center, Double-Blind, Randomized Controlled Trial.

Background and Objectives: Postoperative nausea and vomiting (PONV) is a common adverse effect of general anesthesia, especially in middle ear surgery. Remimazolam is a newer benzodiazepine recently approved for use in general anesthesia. This study aimed to compare the incidence rate of PONV after tympanoplasty with mastoidectomy between using remimazolam and sevoflurane. Materials and Methods: This study included 80 patients undergoing elective tympanoplasty with mastoidectomy. The patients were randomly assigned to either the remimazolam or sevoflurane group. The primary outcome was the incidence rate of PONV 12 h after surgery. The secondary outcomes were the incidence rate of PONV 12-24 and 24-48 h after surgery, severity of PONV, incidence rate of vomiting, administration of rescue antiemetics, hemodynamic stability, and recovery profiles. Results: The incidence rate of PONV 0-12 h after tympanoplasty with mastoidectomy was significantly lower in the remimazolam group compared with that in the sevoflurane group (28.9 vs. 57.9%; p = 0.011). However, the incidence rate of delayed PONV did not differ between the two groups. PONV severity in the early periods after the surgery was significantly lower in the remimazolam group than in the sevoflurane group. The incidence rate of adverse hemodynamic events was lower in the remimazolam group than in the sevoflurane group, but there was no difference in the overall trends of hemodynamic data between the two groups. There was no difference in recovery profiles between the two groups. Conclusions: Remimazolam can significantly reduce the incidence rate of early PONV after tympanoplasty with mastoidectomy under general anesthesia.

Audiologic results of total ossicular replacement prosthesis bypassing the stapes suprastructure in canal wall down mastoidectomy.

OBJECTIVES: Sometimes performing PORP adequately is challenging when the stapes is tilted or the suprastructure is partially damaged owing to inflammation or infection. In such cases, the implementation of a TORP bypassing the stapes can be a useful alternative. This study aimed to investigate whether bypassing the stapes suprastructure during total ossicular replacement prosthesis (TORP) affects postoperative complications or audiological outcomes. MATERIAL AND METHODS: Among 104 patients who underwent open cavity mastoidectomy and ossiculoplasty using a titanium prosthesis at Korea University Ansan Hospital between January 2012 and December 2019, we compared the preoperative and postoperative audiological results and surgical complications of 52, 21, and 31 patients who underwent partial ossicular replacement prosthesis (PORP), TORP bypassing the remaining stapes suprastructure, and TORP on the stapes footplate or oval window, respectively. RESULTS: The air-bone gap before surgery was significantly different in the TORP on the stapes footplate group (34.2 ± 12.0 dB) than that in the PORP (22.9 ± 13.8 dB) and TORP bypassing the stapes groups (20.7 ± 11.5 dB, p < 0.001). After surgery, there were no significant differences among the groups (p = 0.818). The air-bone gap difference before surgery was associated with the presence of stapes before surgery (p < 0.001). There was no difference in the proportion of postoperative tympanic perforation, whether it was a revision surgery, malleus status, or the size of perforation of the tympanic membrane among the three groups. CONCLUSION: When performing ossiculoplasty using TORP, bypassing the stapes did not affect surgical and audiologic outcomes.

Quality of life after revision mastoidectomy with mastoid obliteration.

AIMS: To evaluate the postoperative quality of life (QoL) after revision canal wall down mastoidectomy with mastoid obliteration (rCWD). MATERIAL AND METHODS: A retrospective analysis was conducted on patients treated by rCWD for cholesteatoma between 2016 and 2019. A control group including all patients treated by primary canal wall down with mastoid obliteration (pCWD) for cholesteatoma between 2009 and 2014 was used for the comparison of the postoperative QoL, assessed by the COMQ-12. RESULTS: The rCWD and pCWD groups respectively counted 38 and 78 patients with an average follow-up of 30 and 62 months respectively. No significant difference was found in terms of QoL between the two groups. An intra-group analysis among rCWD patients, showed that patients treated by canal wall down (CWD) at the primary surgery had a significantly worse post-revision QoL compared to those initially treated by canal wall up (CWU), specifically in the hearing and balance domains of the questionnaire. CONCLUSIONS: Revision mastoid obliteration leads to similar QoL results to those obtained after primary CWD with obliteration. Patients who had undergone a CWD as primary surgery complain worse hearing and balance problems compared to those primarily submitted to CWU, even after revision surgery.