Computer Simulation of Optimal Lipped Polyethylene Liner Orientation Against Prosthetic Impingement

Background: Lipped or elevated acetabular liners are to improve posterior stability and are widely used in hip arthroplasty. However, concerns of increasing impingement exist when using such liners and optimal orientation of the elevated rim remains unknown. We aimed to identify the impact of lipped liner on the range of motion (ROM) before impingement and propose its optimal orientation.Methods: An isochoric three-dimensional model of a general hip-replacement prosthesis was generated and flex-extension, add-abduction, axial rotation was simulated on a computer. The maximum ROM of the hip was measured before the neck impinged on the liner. Different combinations of acetabular anteversion angles ranging from 5 to 30 degrees and lipped liner orientations from posterior to anterior were tested. Results: When acetabular anteversion was 10 or 15 degrees, placing the lip of the liner in the posterosuperior of the acetabulum allowed satisfactory ROM in all directions. When acetabular anteversion was 20 degrees, extension and external rotation were restricted. Adjusting the lip to the superior restored satisfactory ROM. When acetabular anteversion was 25 degrees, only placing the lip into the antero-superior could increase extension and external rotation to maintain satisfactory ROM.Conclusions: This study showed that optimal lipped liner orientation should be depend on acetabular anteversion. When acetabular anteversion was smaller than 20 degrees, placing lip in the posterior allowed an optimally ROM. When acetabular anteversion was greater than 20 degrees, adjusting lip to the anterior allowed a comprehensive larger ROM to avoid early impingement.

An Analytical Study of the Factors Affecting Hearing Improvement after Ossiculoplasty – A Retrospective Study, Mathura, Uttar Pradesh

BACKGROUND Otologists always yearn to improve the hearing outcome of their patients with chronic suppurative otitis media. There are different options for ossiculoplasty to choose from, depending on the extent of disease, condition of ossicular chain and availability of implant material and there has always been a quest to make appropriate decision with a predictable outcome. In this study, we have tried to analyse various factors which can affect hearing outcome after Ossiculoplasty. METHODS A retrospective study was done to study the effect of implant material, condition of ossicular chain and disease in the mastoid on post-operative hearing improvement on 200 patients, who underwent tympanoplasty or tympanomastoidectomy from January 2018 to January 2020, in Department of Otorhinolaryngology and Head and Neck Surgery, K.D. Medical College, Mathura. Decision of ossiculoplasty was made based on intra-operative findings. Autograft incus, Teflon TORP (total ossicular replacement prosthesis) and cartilage columella were used based on availability and feasibility. RESULTS Mean improvement in average air-bone gap of 200 patients was found to be 18.57 dB, with autograft incus, it was 19.99 dB, with Teflon TORP (total ossicular replacement prosthesis), 19.53 dB and with cartilage columella 16.73 dB (P = 0.023). Mean hearing improvement was 18.98 dB when handle of malleus was present and 15.59 dB when it was absent (P = 0.023). Mean hearing improvement was 19.42 dB when stapes superstructure was present and 16.92 dB when it was absent (P = 0.016). Even though the hearing outcome was better when mastoid was disease free (19.57 dB) compared to when it was diseased (18.30 dB), the difference was not statistically significant. (P = 0.177) CONCLUSIONS In our study, we found autograft incus to be the best material for ossiculoplasty and presence of handle of malleus and stapes superstructure improved postoperative hearing outcome significantly but involvement of mastoid by disease did not significantly affect the hearing outcome post-operatively. KEYWORDS Chronic Suppurative Otitis Media, Ossiculoplasty, Tympanoplasty, Ossicular Prosthesis, Autograft

Isolated Traumatic Dislocation of the Malleus into the External Auditory Canal

We report a rare case of isolated malleus dislocation into the external auditory canal with lateralized intact tympanic membrane following a head trauma. The patient was a 63-year-old woman who presented at the outpatient department of our institute with hearing loss of 10 years’ duration after a bicycle accident. During physical examination of the patient, total dislocation of the malleus-like bony structure into the external auditory canal on the right side was observed. In the computed tomography scan, an isolated malleus dislocation with intact incus-stapes articulation was identified. The patient was successfully treated with endoscopic exploratory tympanotomy and partial ossicular replacement prosthesis. The isolated malleus dislocation can rarely occur after trauma. A careful diagnostic step through history, physical examination, and temporal bone computed tomography scan are needed to confirm this rare condition.

Is Ossiculoplasty Necessary in Canal Wall Down Mastoidectomy? Comparison of Clinical Outcomes Between Type 0 Tympanoplasty and Ossiculoplasty

Background and Objectives: To assess whether the audiological and clinical outcomes of type 0 tympanoplasty (T0) performed using cartilage were comparable with those of ossiculoplasty in patients who underwent canal wall down mastoidectomy (CWDM).Subjects and Methods: This study included patients who had chronic otitis media with cholesteatoma and underwent CWDM with ossiculoplasty involving partial ossicular replacement prosthesis (PORP), total ossicular replacement prosthesis (TORP), or T0. Anatomical success rates and hearing outcomes were analyzed.Results: Seventy-two patients were included in this study; 29 of them underwent CWDM with T0, 27 underwent CWDM with PORP, while 16 underwent CWDM with TORP. The difference in mean improvement in the air-bone gap (ABG) between the groups was not significant. The differences in the rates of ABG closure to ≤10 dB HL (p=0.030) and ≤20 dB HL (p=0.029) were significant. There were significant differences in improvements in the ABG at 3 kHz among the PORP, TORP, and T0 groups.Conclusions: The audiological outcomes of CWDM with ossiculoplasty seemed to be better than those of CWDM with T0 with no significant difference in the incidence of complications following ossiculoplasty and T0.

Frequency-Specific Analysis of Hearing Outcomes Associated with Ossiculoplasty Versus Stapedotomy

Objective: Surgery on the ossicular chain may impact its underlying mechanical properties. This study aims to investigate comparative differences in frequency-specific hearing outcomes for ossiculoplasty versus stapedotomy. Methods: A retrospective chart review was conducted on subjects who underwent ossiculoplasty with partial ossicular replacement prosthesis (PORP) or laser stapedotomy with self-crimping nitinol/fluoroplastic piston, and achieved closure of postoperative pure tone average air-bone gap (PTA-ABG) ≤ 15 dB. 45 PORP and 38 stapedotomy cases were included, with mean length of follow-up of 7.6 months. Results: The mean change in PTA-ABG was similar for the 2 procedures (−17.9 dB vs −18.1 dB, P = .98). Postoperative ABG closure for stapedotomy was superior at 1000 Hz (8.9 dB vs 13.9 dB, P = .0003) and 4000 Hz (11.8 dB vs 18.0 dB, P = .0073). Both procedures also had improved postoperative bone conduction (BC) thresholds at nearly all frequencies, but there was no statistical difference in the change in BC at any particular frequency between the 2 procedures. Conclusion: Both procedures achieved a similar mean change in PTA-ABG. Stapedotomy was superior to PORP at ABG closure at 1000 Hz and at 4000 Hz, with 1000 Hz the most discrepant. The exact mechanism responsible for these changes is unclear, but the specific frequencies affected suggest that differences in each procedure’s respective impact on the native resonant frequency and mass load of the system could be implicated.