Is the Presence of Transient Evoked Otoacoustic Emissions in Ears With Acoustic Neuroma Significant (original) (raw)
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Hearing Preservation after Acoustic Neuroma Surgery
Skull Base Surgery, 2000
With the advent of microsurgery, techniques for a removal of acoustic neuroma (AN) have improved over the years. We are at a point where tumor extirpation is not the only goal, as preservation of normal cochlear function can be obtained and expected as well, especially in the case of small tumors. The advent of MRI has enabled the surgeon to detect small tumors in asymptomatic patients; thus, preservation of hearing becomes more critical, with as many as 20% of patients with AN presenting as candidates for hearing preservation.' This article presents the hearing results in our series of patients with AN, operated on for hearing preservation surgery by the middle fossa (MF) or the suboccipital (SO) approach, as well as the factors influencing the final outcome.
The Laryngoscope, 1997
Three hundred sixty-four patients referred to the Chicago Otology Group for acoustic tumor removal between 1981 and 1995 were reviewed in a retrospective fashion. Of this group, 60 patients were candidates for hearing preservation surgery and thus underwent one of two surgical approaches to remove the tumor and preserve hearing. Eighteen patients had tumor removal via the middle cranial fossa approach, and 42 patients had tumor removed via the retrosigmoid approach. Of the 42 patients who underwent retrosigmoid removal, 33% had hearing preserved overall. Of the 18 patients in the middle fossa group, 44% had hearing preserved overall. The average tumor size of patients with preserved hearing in the retrosigmoid group was 1.4 cm, and in the middle fossa group was 0.74 cm. Of significance was the fact that in both groups of patients with a tumor of 1.5 cm or less there was a 50% chance of hearing preservation. In the group of patients with tumors larger than 1.6 cm there was only a 16% chance of preserving hearing. We propose that these data can be used for better counseling of patients preoperatively as to the chances of hearing preservation and the type of approach appropriate for each case.
Hearing Preservation Outcomes and Prognostic Factors in Acoustic Neuroma Surgery: Predicting Cutoffs
Otology & Neurotology, 2020
To investigate the outcomes of hearing preservation surgery (HPS) for acoustic neuroma and quantify tumor and patient characteristics predictive of hearing preservation after surgery. Study Design: Retrospective study. Setting: Tertiary referral center. Patients: A total of 100 consecutive patients diagnosed with acoustic neuroma from 2000 to 2012. Intervention: Hearing preservation surgery through microscopic retrosigmoid approach combined with a retrolabyrinthine meatotomy. Main Outcome Measure: Pre-and postoperative hearing stratified according to the American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) and the Tokyo classifications. The most accurate cutoff was identified for each tumor and patients' variable affecting the outcome by calculating the Youden index. A multivariable analysis was undertaken at these cutoffs to identify prognostic factors for hearing preservation. Results: Preoperative hearing class was preserved after surgery in 31% (AAO-HNS), and 39% (Tokyo classification) of patients. According to the AAO-HNS classification, the tumor size in the cerebello-pontine angle, pure-tone average (PTA), and speech discrimination score cutoffs for predicting good postoperative hearing function were 7 mm, 21 dB, and 90%, respectively. With the Tokyo classification, only the PTA cutoff differed, with 27 dB. On multivariable analysis, tumor size and PTA were independent prognostic factors for postoperative hearing with high model's goodness of fit (area under the curve ¼ 0.784; 95% CI ¼ 0.68-0.88 and area under the curve ¼ 0.813; 95% CI ¼ 0.72-0.90), according to both the hearing classifications. Conclusions: The estimated cutoffs for tumor size and PTA were independently associated with HPS. These factors should be prospectively investigated before they are adopted as selection criteria for HPS.
Mechanisms of auditory impairment during acoustic neuroma surgery
Otolaryngology - Head and Neck Surgery, 1997
Hearing loss during removal of acoustic neuroma (AN) may be due to labyrinthine and/or neural and/or vascular damage. Surgical maneuvers relating to perioperative and postoperative hearing may give rise to mechanisms of auditory impairment. Recording action potentials from the intracranial portion of the cochlear nerve (CN) has proven particularly useful for identifying the mechanisms of iatrogenic auditory injury. In this paper intraoperative and postoperative auditory impairments are investigated in relation to surgical steps in a group of 47 subjects with AN (size ranging from 5 to 25 mm) undergoing removal by a retrosigmoid-transmeatal approach. Drilling of the internal auditory canal (IAC), removal of the AN from the IAC fundus, coagulation close to the CN, lateral to medial tumor traction, separation of the CN from the facial nerve, and stretching of the CN have proven to be the most critical surgical steps in hearing preservation. On the other hand, maneuvers such as intracapsular tumor removal, vestibular neurectomy, suction close to the AN, and closure of the IAC defect did not correlate with changes in auditory potentials. Predisposing factors to postoperative hearing deterioration were IAC enlargement greater than 3 ram, IAC tumor size greater than 7 mm, extracanalar tumor size greater than 20 mm, labyrinth medial to the IAC fundus, severe involvement of the CN in the IAC, preoperative abnormal auditory brainstem responses, and normal vestibular reflectivity. Age and preoperative hearing did not prove to be statistically related to postoperative hearing. The variations in morphology and latency of CNAPs are discussed in relation to the mechanisms of iatrogenic injury.
Journal of Neurosurgery, 1985
✓ Microsurgical techniques have made it possible to identify and preserve the cochlear nerve from its origin at the brain stem and along its course through the internal auditory canal in patients undergoing removal of small or medium-sized acoustic neuromas or other cerebellopontine angle (CPA) tumors. In a consecutive series of 100 patients with such tumors operated on between 1975 and 1981, an attempt was made to preserve the cochlear nerve in 23. The decision to attempt to preserve hearing was based on tumor size and the degree of associated hearing loss. In cases of unilateral acoustic neuroma, the criteria for attempted preservation of hearing were tumor size (2.5 cm or less), speech reception threshold (50 dB or less), and speech discrimination score (60% or greater). In patients with bilateral acoustic neuromas or tumors of other types, the size and hearing criteria were significantly broadened. All patients were operated on through a suboccipital approach. Hearing was preser...
Neurosurgery, 2010
BACKGROUND For hearing preservation in acoustic neuroma (AN) surgery, the middle fossa (MF) or retrosigmoid (RS) approach can be used. Recent literature advocates the use of the MF approach, especially for small ANs. OBJECTIVE To present our critical analysis of operative results comparing these 2 approaches. METHODS We reviewed 504 consecutive AN resections performed between November 1998 and September 2007 and identified 43 MF and 82 RS approaches for tumors smaller than 1.5 cm during hearing preservation surgery. Individual cases were examined postoperatively with respect to hearing ability, facial nerve activity, operative time, blood loss, and symptoms resulting from retraction of the cerebellar or temporal lobes. RESULTS Good hearing function (American Academy of Otolaryngology-Head and Neck Surgery class B or better) was preserved in 76.7% of patients undergoing surgery via the MF approach and in 73.2% of the RS group (P = .9024). Temporary facial nerve weakness was more freq...