Nigel Biggs

The use of cone-beam computed tomography to determine cochlear implant electrode position in human temporal bones.

Objective To assess the utility of cone-beam computed tomography (CBCT) imaging in the estimation of cochlear implant (CI) electrode position in implanted temporal bones. Study Design Eight fresh frozen temporal bones were mounted and oriented as for standard surgery and were implanted with Cochlear Slim-Straight (SS) or Contour Advance electrode arrays by 2 CI surgeons. The bones were then imaged using an Accuitomo F170 CBCT scanner (isometric 250 &mgr;m voxel size) and were then processed for histologic sectioning (500 &mgr;m sections). Main Outcome Measures The CBCT images and the histologic micrographs (providing the “gold standard”) were examined independently by several observers who assessed the scalar position (tympani or vestibuli) of each electrode in each temporal bone specimen. Results Examination of the histologic micrographs confirmed that all electrodes were positioned within the scala tympani in all 8 bones. Similar judgments were made by the observers rating the CBCT images, except that one of the 2 observers estimated some of the apical electrodes to be located in the scala vestibuli in two of the bones implanted with the SS electrode. Conclusion Cone-beam CT imaging is able to provide a good indication of the scalar position of implanted electrodes, although estimation may be slightly less reliable for apical electrodes and for straight electrode designs. Additional advantages of using CBCT for this purpose are shorter acquisition time and reduction of radiation dose as compared with conventional CT.

The Prevalence of Cochlear Obliteration After Labyrinthectomy Using Magnetic Resonance Imaging and the Implications for Cochlear Implantation.

Objectives The aim of this study was to determine the prevalence of cochlear obliteration after labyrinthectomy. Study Design Retrospective review of medical records. Setting Tertiary referral center. Patients Sixty-five patients who had previously undergone resection of an acoustic neuroma through a translabyrinthine approach. Intervention The magnetic resonance studies were analyzed as part of the routine surveillance after tumor resection. Main Outcome Measure To determine whether the cochlear lumen remained fluid filled. Results Sixty-five cochleas were examined. Forty-four cochleas were patent and, of the remaining 21, 9 were obliterated and 12 were partially obliterated. The average length of follow-up for the patent, partially obliterated, and obliterated cochlea groups was 47, 29, and 77 months, respectively. Conclusion Obliteration of the cochlea, either partially or completely, occurs in approximately one-third of patients. Time elapsed after labyrinthectomy did not seem to be a predictor of cochlear obliteration.

Schwannoma of the chorda tympani

The authors present a rare clinical entity in a schwannoma of the chorda tympani. The case is discussed including the difficulty in making the diagnosis and management.

Quality of Life in Vestibular Schwannoma Patients Managed by Surgical or Conservative Approaches.

Objective The aim of our study was to assess quality of life (QOL) among patients who underwent microsurgical excision of vestibular schwannoma (VS) compared with those managed conservatively. Study Design Retrospective study. Setting Tertiary care center. Patients There was a total sample population of 376 patients diagnosed with a unilateral VS. Intervention A total of 223 patients with unilateral VS returned the mailed questionnaires. These were then divided into two groups—78 that had undergone microsurgical excision and 145 that were managed conservatively. Subgroups within these primary groups were created for analysis. Main Outcome Measure The primary outcome measure was the Medical Outcomes Study 36 Items Short Form (SF-36). The Dizziness Handicap Inventory test, Hearing Handicap Inventory test, and Tinnitus Handicap Inventory were also used. Results The surgically managed group had a worse QOL when compared with the conservatively managed group using SF-36, significantly so in the domains of physical role limitation and social functioning. Trends were seen toward a better QOL in some domains in the subgroups of male patients and patients younger than 65 years. Worse QOL scores in the Tinnitus Handicap Inventory were seen in the subgroups with larger tumor size. Finally, on correlation analysis between all handicap inventories and SF-36, handicap due to disequilibrium had the strongest correlation with worsening of QOL. In SF-36, the vitality domain showed the greatest correlation with otologic handicap overall, whereas the role emotional domain showed the least. Conclusion This study found that worse QOL scores for surgically managed versus conservatively managed VS patients are most significant in the areas of physical role limitation and social functioning. In some areas, patients who are male and younger report better QOL. Handicap due to disequilibrium seems to have the greatest negative impact on QOL. These factors should be considered when counseling patients regarding approach to VS, in the context of an experienced management program.

Management of cystic facial neuromas: an alternative approach.

Objective: To describe the treatment of cystic facial neuroma with drainage and marsupialization as an alternative to tumor removal and facial nerve grafting. Study Design: Retrospective case review. Setting: Tertiary referral hospital. Patients: Two cases of cystic facial neuroma. Main Outcome Measures: Maintenance of facial nerve function at or better than preoperative function. Results: Both cases were managed with cyst drainage. Case 1 retained House-Brackmann Grade I facial nerve function. Case 2 retained Grade II function. Conclusion: Cyst drainage provides a useful alternative to tumor removal and nerve sacrifice in patients with predominantly cystic facial neuromas and serviceable facial function.

External auditory canal meningoencephalocele with spontaneous cerebrospinal otorrhea.

A seventy-three-year-old male presented with a 2-month history of intermittent watery discharge from his left ear. He denied any other associated otological symptoms or surgery, or any significant head trauma. Of interest, however, was a single episode of bacterial meningitis 10 years earlier. Otological examination of his left ear revealed a soft fluctuant discharging bleb in the superior aspect of his external ear canal adjacent to an intact tympanic membrane (Fig 1). His right ear was unremarkable. A sample of left ear fluid was positive for beta 2-transferrin, confirming the presence of cerebrospinal fluid (CSF). A high-resolution CT scan was performed and revealed erosion of the tegmen tympani bilaterally. An MRI was also obtained and demonstrated soft tissue densities within the middle ear and mastoid on both sides (Fig 2). A diagnosis of bilateral meningoencephaloceles was made. The patient underwent a combined left transmastoid and middle fossa craniotomy to identify and repair the tegmen defect. The gliotic neural tissue within the encephalocele was excised and sent for histopathology. The repair was accomplished by using a multilayer calvarial bone-temporalis fascia sandwich graft secured with DuraGen (Integra Life Sciences, USA). He has made an uneventful postoperative recovery with gradual resolution of the external canal out-pouching. A CT scan done 5 months postoperatively showed that the calvarial bone graft remained in a good position with no recurrence.

The use of cone beam imaging to determine cochlear implant electrode position in human temporal bones

Abstract This paper describes the outcomes of cochlear implantation in eight cadaveric temporal bones using cone-beam CT imaging and histological examination with respect to scalar position of the electrode array.

Perineural trigeminal nerve abscess secondary to Mucor sinusitis: Serial diffusion-weighted MRI and literature review

Perineural trigeminal nerve abscess secondary to Mucor sinusitis: Serial diffusion-weighted MRI and literature review J. Chaganti *, D. Marriott , T. Steel , J. Donovan , N. Biggs d Department of Radiology, St Vincent’s Hospital, Sydney, Australia Department of Infectious Diseases, St Vincent’s Hospital, Sydney, Australia Department of Neurosurgery, St Vincent’s Hospital, Sydney, Australia Department of Otorhinolaryngology, St Vincent’s Hospital, Sydney, Australia

Cochlear Implantation in Ménière's Disease With and Without Labyrinthectomy.

OBJECTIVE To investigate outcomes of cochlear implantation (CI) in patients with Ménières disease (MD) with and without surgical labyrinthectomy. STUDY DESIGN Retrospective study. SETTING Multiple tertiary referral centers. SUBJECTS Thirty one ears from 27 patients (17 men, 10 women, aged 42-84) with CI in ipsilateral MD ear. INTERVENTION CI in ears with intact labyrinths (Group 1), CI with simultaneous surgical labyrinthectomy (Group 2), and CI sequential to surgical labyrinthectomy (Group 3). MAIN OUTCOME MEASURE Within-subject improvement on Bamford Kowal Bench test or City University of New York open set sentence tests. RESULTS Majority of ears achieved excellent open-set speech recognition by 12 months post-CI, irrespective of intervention group. Preoperative details including patient age and sex, implant, MD and previous intervention, and audiological test results did not significantly affect outcomes. Patients with MD undergoing CI only may experience vestibular dysfunction which may cause long-term concerns. Incidental finding was noted of eight ears with fluctuating symptoms in ipsilateral ear during 12-month period post-CI, with five of eight ears showing objective fluctuating impedances and mapping. CONCLUSION CI in MD can yield good hearing outcomes in all three groups and this is possible even after a long delay after labyrinthectomy. Bilateral MD patients are complex and prospective quality of life (QoL) measures would be beneficial in being better able to manage the vestibular outcomes as well as the audiological ones.

Non-exenteration Management of Sino-orbital Fungal Disease

PURPOSE To describe the non-exenteration management of sino-orbital fungal infection, a life-threatening condition for which orbital exenteration is generally considered a first-line treatment. METHODS A retrospective case series is presented of 7 orbits in 6 consecutive patients admitted and treated at 2 major metropolitan tertiary teaching hospitals in Sydney, New South Wales, Australia. RESULTS Seven orbits in 6 consecutive patients with sino-orbital fungal infection were treated conservatively with surgical debridement and intravenous antifungal agents. Four patients were immunosuppressed and the other 2 patients were otherwise healthy. All presented with pain, proptosis, or loss of vision. Causative organisms found were Mucormycoses, Aspergillus, and Scedosporium prolificans. Exenteration was avoided in all patients as part of their planned management and 5 patients, including 1 with bilateral disease, survived their disease without exenteration. Medical treatment included intravenous liposomal amphotericin B or voriconazole. A single immunosuppressed patient deteriorated and as a last resort, exenteration was performed, but this made no difference to his clinical course and in retrospect could have been avoided as he died of multiple cerebral metastases diagnosed shortly after his deterioration. CONCLUSION The authors recommend that patients with sino-orbital fungal disease preferably be treated conservatively, without orbital exenteration.