Daniel Jethanamest

Auditory rehabilitation of patients with neurofibromatosis Type 2 by using cochlear implants

OBJECT The aim of this study was to determine whether patients with neurofibromatosis Type 2 (NF2) who have intact ipsilateral cochlear nerves can have open-set speech discrimination following cochlear implantation. METHODS Records of 7 patients with documented NF2 were reviewed to determine speech discrimination outcomes following cochlear implantation. Outcomes were measured using consonant-nucleus-consonant words and phonemes; Hearing in Noise Test sentences in quiet; and City University of New York sentences in quiet and in noise. RESULTS Preoperatively, none of the patients had open-set speech discrimination. Five of the 7 patients had previously undergone excision of ipsilateral vestibular schwannoma (VS). One of the patients who received a cochlear implant had received radiation therapy for ipsilateral VS, and another was undergoing observation for a small ipsilateral VS. Following cochlear implantation, 4 of 7 patients with NF2 had open-set speech discrimination following cochlear implantation during extended follow-up (15-120 months). Two of the 3 patients without open-set speech understanding had a prolonged period between ipsilateral VS resection and cochlear implantation (120 and 132 months), and had cochlear ossification at the time of implantation. The other patient without open-set speech understanding had good contralateral hearing at the time of cochlear implantation. Despite these findings, 6 of the 7 patients were daily users of their cochlear implants, and the seventh is an occasional user, indicating that all of the patients subjectively gained some benefit from their implants. CONCLUSIONS Cochlear implantation can provide long-term auditory rehabilitation, with open-set speech discrimination for patients with NF2 who have intact ipsilateral cochlear nerves. Factors that can affect implant performance include the following: 1) a prolonged time between VS resection and implantation; and 2) cochlear ossification.

The effect of perimodiolar placement on speech perception and frequency discrimination by cochlear implant users

Conclusion. Neither speech understanding nor frequency discrimination ability was better in Nucleus Contour™ users than in Nucleus 24 straight electrode users. Furthermore, perimodiolar electrode placement does not result in better frequency discrimination. Objectives. We addressed three questions related to perimodiolar electrode placement. First, do patients implanted with the Contour™ electrode understand speech better than with an otherwise identical device that has a straight electrode? Second, do these groups have different frequency discrimination abilities? Third, is the distance of the electrode from the modiolus related to frequency discrimination ability? Subjects and methods. Contour™ and straight electrode users were matched on four important variables. We then tested these listeners on CNC word and HINT sentence identification tasks, and on a formant frequency discrimination task. We also examined X-rays and measured the distance of the electrodes from the modiolus to determine whether there is a relationship between this factor and frequency discrimination ability. Results. Both speech understanding and frequency discrimination abilities were similar for listeners implanted with the Contour™ vs a straight electrode. Furthermore, there was no linear relationship between electrode–modiolus distance and frequency discrimination ability. However, we did note a second-order relationship between these variables, suggesting that frequency discrimination is worse when the electrodes are either too close or too far away from the modiolus.

Image-guided surgical navigation in otology.

To evaluate the efficacy of image‐guided surgical navigation (IGSN) in otologic surgery and establish practice guidelines.

Evaluation of the short hybrid electrode in human temporal bones.

Hypothesis: The current hybrid electrode can be inserted without trauma to the temporal bone and, after insertion, assumes a position within the scala tympani near the outer cochlear wall just beneath the basilar membrane. Background: Conservation of residual hearing after cochlear implant electrode insertion requires a special insertion technique and an atraumatic short electrode. This allows electroacoustic stimulation in ears with significant residual hearing. Methods: Human cadaveric temporal bones were implanted with soft surgical technique under fluoroscopic observation. Dehydrated and resin-impregnated bones are dissected. Real-time electrode insertion behavior and electrode position were evaluated. The bones are examined for evidence of insertion-related trauma. Results: No gross trauma was observed in the implanted bones, and the electrode dynamics evaluation revealed smooth scala tympani insertions. Conclusion: Atraumatic insertion of the 10-mm hybrid electrode can be accomplished using an appropriate cochleostomy and insertion technique.

Conservative management of vestibular schwannoma: Predictors of growth and hearing

To describe the clinical outcomes of patients undergoing serial observation for vestibular schwannoma (VS) and identify factors that may predict tumor growth or hearing loss.

Spontaneous CSF rhinorrhea: prevalence of multiple simultaneous skull base defects.

Background Spontaneous cerebrospinal fluid (CSF) leaks are caused by intracranial hypertension. Given this underlying etiology, patients may be at risk for developing multiple skull base defects. Objective The purpose of our study is to present the prevalence of multiple simultaneous skull base defects in patients with spontaneous CSF rhinorrhea. Methods We performed a retrospective chart review in a tertiary care practice of 44 consecutive patients with spontaneous CSF rhinorrhea who underwent endoscopic repair by the senior author (R.R.C.) to determine the prevalence of having multiple simultaneous skull base defects identified at the time of surgery. We defined this as two or more bony defects identified endoscopically with intact intervening bone with or without soft tissue prolapse into the nasal cavity or paranasal sinus cavity. Results Eight of 44 patients (18.2%) were found to have multiple simultaneous skull base defects. The average body mass index (BMI) of the study population was 34.5 (range, 22.7-59). Conclusion A significant number of patients with spontaneous CSF rhinorrhea may have more than one skull base defect present at the time of presentation. The clinical significance of this finding in surgical and medical decision making is not clear at this time.

Intraoperative Transcranial Motor-Evoked Potential Monitoring of the Facial Nerve during Cerebellopontine Angle Tumor Resection.

Objective To determine whether transcranial motor-evoked potential (TCMEP) monitoring of the facial nerve (FN) during cerebellopontine angle (CPA) tumor resection can predict both immediate and long-term postoperative FN function. Design Retrospective review. Setting Tertiary referral center. Main Outcome Measures DeltaTCMEP (final-initial) and immediate and long-term facial nerve function using House Brackmann (HB) rating scale. Results Intraoperative TCMEP data and immediate and follow-up FN outcome are reported for 52 patients undergoing CPA tumor resection. Patients with unsatisfactory facial outcome (HB >2) at follow-up had an average deltaTCMEP of 57 V, whereas those with HB I or II had a mean deltaTCMEP of 0.04 V (t = -2.6, p < 0.05.) Intraoperative deltaTCMEP did not differ significantly between groups with satisfactory (HB I, II) and unsatisfactory (HB > 2) facial function in the immediate postoperative period. Conclusion Intraoperative TCMEP of the facial nerve can be a valuable adjunct to conventional facial nerve electromyography during resection of tumors at the CPA. Intraoperative deltaTCMEP >57 V may be worrisome for long-term recovery of satisfactory facial nerve function.

Potential hazards of the harmonic scalpel.

We appreciate the thoughtful and analytical approach taken by Dr Chao in response to our article. He correctly points out that if olfactory function (X1) was binary, then the model would need the modifications set forth in the appendix. However, multiple model building approaches exist. In our analysis, we accounted for olfactory function as a categorical variable and our original conclusions hold true. Interestingly, in both models, there was a significant interaction between nasal polyposis and olfaction with regard to olfactory outcomes: anosmic patients with nasal polyposis improved to a greater extent than anosmic patients without nasal polyposis. We have also observed an interaction, or effect modification, with nasal polyposis and other clinical variables in the measurement of post–endoscopic sinus surgery (ESS) improvement. For example, patients with nasal polyposis and a history of prior sinus surgery are as likely to improve on endoscopy scores after ESS as patients undergoing primary surgery. Patients without nasal polyposis and a history of prior ESS are 3.9 times as likely to improve on endoscopic exam after ESS as primary patients. The differences observed in patients with nasal polyposis illustrate the heterogeneity of patients with chronic rhinosinusitis undergoing ESS. Some findings are likely related to the underlying constructs of the instruments used to measure the outcomes of ESS. However, it is also evident that patients with nasal polyposis behave differently than patients without nasal polyposis. As we learn more about the underlying nature of nasal polyposis and continue to study the clinical behavior of these patients, we will also better understand how this dynamic impacts the outcomes of ESS. Jamie R. Litvack, MD, MS Jess Mace, MPH Timothy L. Smith, MD, MPH Division of Rhinology and Sinus Surgery, Oregon Sinus Center Department of Otolaryngology–Head and Neck Surgery Oregon Health & Science University, Portland, OR REFERENCES

Utricular Dysfunction in Refractory Benign Paroxysmal Positional Vertigo.

Objective To determine the prevalence of otolith dysfunction in patients with refractory benign paroxysmal positional vertigo (BPPV). Study Design Unmatched case control. Setting Tertiary care institution. Subjects and Methods Patients included were diagnosed with BPPV, failed initial in-office canalith repositioning maneuvers (CRMs), and completed vestibular testing and vestibular rehabilitation (n = 40). Refractory BPPV (n = 19) was defined in patients whose symptoms did not resolve despite vestibular rehabilitation. These patients were compared with a control group of those with nonrefractory BPPV (n = 21) for results of a caloric test, cervical vestibular evoked myogenic potential (cVEMP), and subjective visual vertical (SVV). Results Forty-six of 251 patients failed initial treatment with in-office CRM. Forty patients met inclusion criteria. There was no significant difference between the cases (refractory BPPV) (n = 19) and controls (nonrefractory BPPV) (n = 21) in terms of age, duration of symptoms, laterality of BPPV, and BPPV symptoms. There was no difference in the prevalence of caloric weakness and cVEMP abnormalities (P > .05), with odds ratios (ORs [95% confidence interval (CI)]) of having abnormal results among cases vs controls of 1.1818 (0.3329-4.1954) and 4.3846 (0.7627-25.2048), for caloric and cVEMP, respectively. Abnormal eccentric SVV was more prevalent in refractory BPPV cases (58%) than in controls (14%) (P < .0072). The OR (95% CI) of having abnormal SVV was 8.25 (1.7967-37.8822) higher among patients with refractory BPPV than those with nonrefractory BPPV. Conclusion Patients with refractory BPPV are more likely to have abnormal eccentric SVV and thus underlying utricular dysfunction. This finding is important to take into account when designing rehabilitation strategies for patients with BPPV who fail CRM.

Fibrous dysplasia of the temporal bone with complete canal stenosis and cholesteatoma.

Fibrous dysplasia was first described by von Recklinghausen in 1891. Involvement of the temporal bone by this disease process was first reported in 1946 (1,2). Cases affecting the temporal bone are uncommon, occurring in less than 10% of all patients (3). Fibrous dysplasia is benign and slowly progressive. Histologically, affected areas demonstrate irregular mixtures of fibrous tissue and mature trabecular bone. Three subtypes of fibrous dysplasia have been described based on the distribution of lesions and associated symptoms. The most common subtype is monostotic fibrous dysplasia which involves a single bone while the polyostotic form involves multiple bones, including the ribs, craniofacial or long bones. McCune-Albright syndrome is the third form and is associated with endocrine abnormalities and cafe-au-lait spots. Non-contrast high resolution computed tomography (CT) of the temporal bone is the study of choice for diagnosing fibrous dysplasia in this area given its superior bony detail. Three different appearances of fibrous dysplasia on CT have been described: pagetoid, sclerotic, and cystic (4). The most common of these, the pagetoid pattern, is characterized by a ground-glass appearance on CT imaging. The sclerotic pattern is represented by uniformly dense bone throughout the lesion. Cystic lesions typically include a central radiolucency surrounded by a dense border. Within the temporal bone, the external auditory canal (EAC) is the area most commonly affected by fibrous dysplasia. The EAC is involved in up to 85% of cases, and manifests as bony protrusions within the EAC or as canal stenosis. (5). We present a unique case of fibrous dysplasia of the temporal bone with early onset complete EAC stenosis presenting as a congenital aural atresia. A 17-year-old boy presented to our clinic with a lifelong history of right hearing loss and canal atresia. He had no history of otorrhea or otitis media in either ear. On physical exam, he had a dry, atretic right EAC. As revealed by high resolution CT, the stenosis was the result of monostotic fibrous dysplasia limited to the temporal bone (Fig. 1A). The lesion demonstrates the classic pagetoid appearance most commonly found when imaging fibrous dysplasia on CT. Extensive soft tissue density consistent with cholesteatoma was identified in the mesotympanum, surrounding the ossicles (Fig. 1B), despite the presence of a patent Eustachian tube. An associated cholesteatoma is present in nearly 40% of fibrous dysplasias of the temporal bone. However, the vast majority of these are canal cholesteatomas created by entrapment of the canal skin due to a bony stenosis and limited to the EAC lateral to an intact tympanic membrane (3,5). Our case represents an unusually extensive cholesteatoma extending from the residual canal to involve the middle ear and ossicular chain in the setting of a patent Eustachian tube (Fig. 1C and 1D). The diagnosis in this case was made exclusively by CT. Although observation is often an option in asymptomatic cases, surgical intervention is appropriate in cases with significant functional deficits or complications such as a secondary cholesteatoma formation (1). Our patient had both a functional deficit (complete conductive hearing loss) and a cholesteatoma, which was treated with canalplasty and tympanomastoidectomy. Intraoperatively, we noted the cholesteatoma had eroded the long process of the incus. Figure 1 (A) Axial high resolution temporal bone CT through the plane of the cochlea. CT imaging reveals a pagetoid pattern of bony development (asterisk), with a focus of soft tissue density within the middle ear space adjacent to the ossicular chain (arrow) ... The differential diagnosis of bony lesions of the temporal bone includes Paget’s disease, which presents with diffuse involvement of the temporal bone and calvarium. Ossifying fibromas, which have a well demarcated border on CT imaging, can also mimic the cystic pattern of fibrous dysplasia. Other bony lesions to consider are exostoses, osteomas, osteochondromas, giant cell granulomas and aneurysmal bone cysts. Patients commonly present with some degree of canal stenosis and an associated progressive conductive hearing loss. Onset of symptoms in aural atresia is more common within the first two decades of life, and onset in infancy has been reported in different subsites. However, fibrous dysplasia is not typically listed in the differential for congenital aural atresia and though rare should be considered. Patients with functional deficits or suspected cholesteatoma are surgical candidates. Although recurrence after surgery has been reported in up to 49% of patients, appropriately timed interventions in conjunction with long term follow-up can improve hearing loss and prevent complications (1,5).