Impact of extent of internal acoustic meatus tumor removal using translabyrinthine approach for acoustic neuroma surgery

Objectives Many studies have investigated the surgical outcome and predictive factors of acoustic neuroma using different approaches. The present study focused on large tumors due to the greater likelihood of internal acoustic meatus involvement and the greater application of surgical intervention than radiosurgery. There have been no previous reports on outcomes of internal acoustic meatus tumor removal. We investigated the impact of the extent of internal acoustic meatus tumor removal using a translabyrinthine approach for large acoustic neuroma surgery and predictive factors of tumor control. Methods This retrospective study reviewed 104 patients with large cerebellopontine angle tumor >3 cm treated by translabyrinthine approach microsurgery. Predictive factors of postoperative facial palsy, tumor control, and extent of internal acoustic meatus tumor removal were assessed. Results The mean tumor size was 38.95 ± 6.83 mm. Postoperative facial function showed 76.9% acceptable function (House–Brackmann grade 1 or 2) six months after surgery. The extent of internal acoustic meatus tumor removal was a statistically significant predictor factor of poor postoperative facial function. Younger age, larger tumor size needing radiosurgery, and more extensive removal of tumor were associated with better tumor control. Conclusion More extensive internal acoustic meatus tumor removal was associated with poor postoperative facial function and better tumor control.

Invasive Corridor of Clivus Extension in Pituitary Adenoma: Bony Anatomic Consideration, Surgical Outcome and Technical Nuances

BackgroundIt is well known that the clivus is composed of abundant cancellous bone and is often invaded by pituitary adenoma (PA), but the range of these cancellous bone corridors is unknown. In addition, we found that PA with clivus invasion is sometimes accompanied by petrous apex invasion, so we speculated that the petrous apex tumor originated from the clivus cancellous bone corridor. The aim of this study was to test this hypothesis by investigating the bony anatomy associated with PA with clival invasion and its clinical significance.MethodsTwenty-two cadaveric heads were used in the anatomical study to research the bony architecture of the clivus and petrous apex, including six injected specimens for microsurgical dissection and sixteen cadavers for epoxy sheet plastination. The surgical videos and outcomes of PA with clival invasion in our single center were also retrospectively reviewed.ResultsThe hypoglossal canal and internal acoustic meatus are composed of bone canals surrounded by cortical bone. The cancellous corridor within clivus starts from the sellar or sphenoid sinus floor and extends downward, bypassing the hypoglossal canal and finally reaching the occipital condyle and the medial edge of the jugular foramen. Interestingly, we found that the cancellous bone of the clivus was connected with that of the petrous apex through petroclival fissure extending to the medial margin of the internal acoustic meatus instead of a separating cortical bone between them as it should be. It is satisfactory that the anatomical outcomes of the cancellous corridor and the path of PA with clival invasion observed intraoperatively are completely consistent. In the retrospective cohort of 49 PA patients, the clival component was completely resected in 44 (89.8%), and only five (10.2%) patients in the early-stage had partial residual cases in the inferior clivus.ConclusionThe petrous apex invasion of PA is caused by the tumor invading the clivus and crossing the petroclival fissure along the cancellous bone corridor. PA invade the clivus along the cancellous bone corridor and can also cross the hypoglossal canal to the occipital condyle. This clival invasion pattern presented here deepens our understanding of the invasive characteristics of PA.

Primary Lymphoma of Internal Acoustic Meatus Mimicking Vestibular Schwannoma—A Rare Diagnostic Dilemma

Background/Setting A subject presenting with a unilateral sensorineural hearing loss and with vertigo/imbalance and a lesion of internal acoustic meatus (IAM) most often represents a vestibular schwannoma. Several alternative pathologies involving the region, with clinical and neuroradiological similarities, could lead to an error in judgement and management. Rare tumors of the IAM pose unique diagnostic difficulty. A rare case that we present here had a typical history and imaging findings suggestive of vestibular schwannoma. A primary central nervous system (CNS) lymphoma was diagnosed in later stages of brain involvement warranting a retrospective analysis of the entity. Case Summary An 80-year-old male presented with unilateral sensorineural hearing loss, vertigo, and imbalance. On imaging, he was found to have a lesion in the left internal auditory meatus, reported as a vestibular schwannoma and operated upon. Subject's condition worsened with time and a repeat imaging was suggestive of a CNS lymphoma with lesions involving bilateral cerebellum and subcortical white matrix. Conclusion To conclude, primary CNS lymphoma presenting an isolated lesion in the IAM with no other parenchymal lesions at presentation is a rare incidence; to our knowledge this is the first case of such unique presentation.

The first Malaysian experience on totally endoscopic ear surgery

Introduction: Totally endoscopic ear surgery (TEES) is defined as exclusive application of endoscope transcanally in otologic surgery. This study is aimed to highlight indications and ear pathologies for TEES. In addition, intraoperative, early postoperative and delayed postoperative complications of TEES will be also described in this study. Methodology: This is a retrospective study of TEES performed by a single experienced and trained otologist in endoscopic ear surgery in a single institution between 1 July 2014 and 31 June 2018. A total of 43 patients were recruited in this study. Sociodemographic information, indications for TEES, ear pathologies, type of surgery performed and complications of TEES were analyzed. Results: The indications for TEES comprised middle ear lesion (65.1%), followed by second look surgery (14.0%), external auditory canal lesion (11.6%) and internal acoustic meatus lesion and surgery for conductive hearing loss which were 4.7%. Various external auditory canal pathologies encountered for TEES were ear canal osteoma (4.7%), acquired ear canal stenosis (2.3%) and tumor (4.7%). Regarding middle ear pathologies, limited atticoantral cholesteatoma accounted for most of the cases, 46.5%. Other middle ear lesions included adhesive otitis media (14.0%), recurrent cholesteatoma (14.0%), tumor (4.7%), otosclerosis (2.3%) and ossicular discontinuity (2.3%). Internal acoustic meatus lesion constituted 4.7% of cases. Some 4.7% of cases developed intraoperative complications, while early and delayed complications were 7.0%. Conclusion: TEES is a feasible surgical technique for diverse ear pathologies in the otologic specialty. It is also proven to be safe with good surgical outcomes.

The Morphometric study of Internal acoustic meatus in dry skulls of South Indian adults

Background: The internal acoustic meatus (IAM) is a bony canal present between labyrinth and posterior cranial fossa. The normal morphometry of IAM is useful during evaluation of cases of skull trauma, congenital anomalies of IAM affecting the individual nerves, and in pre evaluation of surgeries of ear. The present study was done to determine the normal dimensions of IAM and to have a morphological database of the IAM for South Indian population. Materials & methods: The present study was conducted on 37 temporal bones of adult skulls. The impression of IAM was taken by injecting polyvinyl siloxane (PVS) impression material into the IAM and the dimensions were measured by using digital vernier callipers on right and left side separately. The height and width of IAM at porous, middle and fundus were measured and tabulated. Results: As there was no significant statistical difference between the parameters of right and left sides the data were pooled together. The mean height & width of IAM at porous end was 4.5mm & 6.42mm respectively. The mean height & width of IAC at its middle portion was 4.04mm & 4.91mm respectively. The mean height & width of IAM at the fundus was 3.8mm and 4.60mm respectively. The superior length & inferior length was 8.60 & 8.70mm respectively. Conclusion:This study provides a ready reference for dimensions of IAM of adult dry skull in South Indian population. The present study confirms that there is difference in the dimensions of IAM among different races and regions and thus emphasizes the need to have normal data for our population.