Management of idiopathic sudden sensorineural hearing loss.

OBJECTIVE: To determine if any consensus exists regarding the efficacy of treatment in idiopathic sudden sensorineural hearing loss syndrome (ISSNHL). DATA SOURCES: A review of the literature from 1966 to the present on Medline database was performed with the following search criteria: Hearing loss, sensorineural (MeSH terms), sensorineural hearing loss (text word), deafness (MeSH), and idiopathic or sudden (all fields). Further limiting search terms were treatment outcomes or controlled studies. DATA EXTRACTION: The articles were then analyzed searching for randomized, prospective, controlled studies of single treatment modalities. Both human and animal studies were included for discussion because of the paucity of human studies. CONCLUSION: No consensus exists on the effective treatment of ISSNHL. Randomized, controlled studies have demonstrated the effectiveness of systemic steroids, however, follow up studies have questioned the benefit of steroid therapy.

Surgical techniques to facilitate endoscopic second-look mastoidectomy.

OBJECTIVES/HYPOTHESIS: Mastoidoscopy has shown to be a safe, effective alternative to traditional second-look mastoidectomy. This study was undertaken to review surgical modifications to facilitate successful mastoidoscopy. STUDY DESIGN: Retrospective database review of all surgical procedures performed by the senior author (T.J.H.) since January 1995. All surgeries were performed in a tertiary hospital setting. RESULTS: Fifteen second-look procedures were performed in this series. Five were performed endoscopically, 10 with traditional techniques. In the traditional surgeries five were prior to the use of endoscopy, five had contraindications to endoscopic mastoidectomy. There were six residual cholesteatomas in the series, one in the endoscopic cases (20%), and five in the traditional cases (50%). No cholesteatomas were identified with microscopic examination performed after endoscopy. There were no complications in the series. Mastoidoscopy gives limited access to the mesotympanum, eustachian tube and, in particular, the sinus tympani. The creation of a wide extended facial recess with removal of the buttress at the fossa incudis and removal of the incus and head of the maleus will facilitate inspection of the middle ear. Additional techniques are necessary to view the sinus tympani. The fallopian bridge technique, and the infratympanic extended facial recess technique may allow better visualization of the middle ear. CONCLUSION: Mastoidoscopy offers a safe alternative to traditional techniques for second-look surgery. The morbidity appears similar to traditional techniques.

Surgical exposure of the fundus of the internal auditory canal: anatomic limits of the middle fossa versus the retrosigmoid transcanal approach.

OBJECTIVE: To define the anatomic limitations and advantages of the middle cranial fossa and the retrosigmoid transcanal approaches in the exposure of the fundus of the internal auditory canal (IAC). STUDY DESIGN: A series of 15 cadaver temporal bone specimens were dissected and the measurements of the lateral recess of the IAC were made with a millimeter rule and rounded to the nearest quarter millimeter. METHODS: Retrospective case review, surgical observation, review, and measurements recorded from magnetic resonance scans. Surgical observations and measurements recorded from cadaver specimens. RESULTS: These results were compared with historical studies of the retrosigmoid transcanal approach. The results utilizing a combination of these approaches to remove acoustic neuromas at a tertiary referral center during the preceding 11 years are also presented. Previous studies have shown that for the retrosigmoid transcanal approach, it is impossible to expose 3 to 4 mm of the lateral recess of the IAC without violating the vestibule and/or the endolymphatic duct. This has led some authors to advocate the middle cranial fossa approach to the IAC when hearing preservation is a consideration. The current study shows that the falciform crest obscures the inferior half of the fundus. This creates a pocket that cannot be visualized, which on average is 1.82 x 2.33 mm. CONCLUSION: The fundus of the IAC cannot be completely exposed without violating the labyrinth through either the posterior fossa or middle fossa approach. The clinical implications of these studies are unknown at this time. Low recurrence rates are achieved with both approaches. The anatomic limitations of both approaches must still be considered when planning or performing these approaches, to minimize the risk of recurrence.

Stapedectomy training with the carbon dioxide laser.

All primary carbon dioxide (CO2) laser stapedectomies supervised by the senior author since 1986 were retrospectively reviewed and reported according to 1995 American Academy of Otolaryngology-Head and Neck Surgery Committee on Hearing guidelines. Sixty-three cases had more than 6 weeks of follow-up with an average residual gap of 6.49 dB (SD = 5.55 dB) and an 89% success rate. Thirty cases had more than 1 year of follow-up with the average hearing result of 6.58 dB (SD = 5.93 dB) and an 87% success rate. In 11 cases, 14 operative problems or complications occurred. Suctioning the vestibule occurred in five cases. Because suction is required to evacuate laser smoke, these cases are attributed to the laser. One of these patients had delayed sensorineural hearing loss. One patient had profound delayed sensorineural hearing loss as a result of granuloma formation. These were the only major complications. The laser is a tool that gives reproducible technique and good success rates.

Surgical anatomy of the transtemporal approaches to the petrous apex.

HYPOTHESIS: This study was undertaken to compare the subcochlear and infralabyrinthine approaches to the petrous apex. BACKGROUND: Both approaches are advocated to drain cholesterol granuloma or biopsy lesions of the petrous apex. There is little data directly comparing these approaches. METHODS: Anatomic dissections were performed on 20 preserved temporal bones. The anatomic distances were measured to the nearest quarter millimeter using a two-point needle caliper. Measurements were repeated three times and averaged. RESULTS: The average window created through the subcochlear approach was 9.41 x 7.33 mm. The approach is performed between the carotid artery, jugular bulb, and basal turn of the cochlea, and gives a roughly triangular window in most cases. The cochlear aqueduct and glossopharyngeal nerve may be exposed during this approach. The subcochlear approach provided a more consistent exposure (SD of 3.5 x 1.9) and was always possible. Still, the exposure obtained through this approach may be limited if the hypotympanic air cell tract is sclerotic. The infralabyrinthine approach gave adequate exposure in most cases, but a high-lying jugular bulb obstructed this approach completely in eight of 20 cases. The average window created was 4.99 x 7.23 mm (SD 4.4 x 1.3). CONCLUSIONS: The availability of a particular approach to the petrous apex and the exposure obtained varies considerably in individual cases. The choice of a surgical approach to the petrous apex should be influenced by the location of disease, the type of disease, the existing anatomy, and the experience of the surgeon.

Mobius syndrome: electrophysiologic studies in seven cases.

Mobius syndrome is characterized by congenital facial diplegia, frequent impairment of gaze, variable involvement of other cranial muscles, and various musculoskeletal anomalies. The site of dysfunction remains debatable. We performed detailed electrophysiologic studies in 5 children and 2 adults with Mobius syndrome to better delineate the pathophysiology of this disorder. Sensory and motor conduction studies were normal in the extremities. Facial compound muscle action potential amplitudes were reduced in all patients. The blink reflex R1 responses were unobtainable unilaterally in 2 patients and unobtainable bilaterally in 3 patients. Otherwise, R1 and R2 latencies were variably prolonged. The jaw jerk and masseter silent periods, tested in 2 patients, were normal. Detailed electromyographic studies of facial muscles revealed multifocal, chronic neurogenic changes. The findings indicate a brain stem process predominantly affecting the facial nuclei and their internuclear connections rather than a supranuclear or muscular site of involvement.

Sudden sensorineural hearing loss.

Approximately 4000 new cases of sudden hearing loss (SHL) occur annually in the United States, and 15,000 annually worldwide, accounting for approximately 1% of all cases of SHL. Although prevalence studies do not necessarily distinguish between idiopathic and acquired SHL, most cases of spontaneous SHL have no identifiable cause. In this article, the authors assess the cause, history, diagnosis, and treatment of SHL.

Revision stapedectomy with and without the CO2 laser: an analysis of results.

A retrospective review is presented of revision stapedectomies performed by the senior authors between 1986 and 1994. A total of 106 stapedectomies was performed during that period, of which 30 were revisions. These revisions were within the first 100 stapedectomies performed by the senior authors. Most failures occurred early in the series. The overall success rate for closure to within 10 dB was 52%, and the average closure was 12.72 dB. Five cases were performed without the laser with no successes and an average closure of 27 dB. After the use of the laser, the success rate was 64%, and the average closure was 9.75 dB. There was a statistically significant difference between the hearing results with and without the laser (p < 0.01). The prognosis was better when surgery was performed primarily for hearing loss and with the laser, with success in 13 (72%) or 18 cases. In two cases, there was a sensorineural decline > 10 dB. The only dead ear occurred preoperatively in a patient with a granuloma. We have found the use of the CO2 laser in revision stapedectomy to be a safe technique that produces reliable results.

Gunshot injuries of the temporal bone.

Despite an increasing incidence of gunshot wounds to the temporal bone, there is little in the literature regarding management of survivors of these serious injuries. Twelve patients were treated for such wounds between 1986 and 1994. The most frequent presentations were cranial nerve injury, especially facial paralysis (9 patients), hearing loss (7), vascular injury (4), and vestibular dysfunction (3). Persistent cerebrospinal fluid otorrhea was uncommon (1 patient) in this series. Computed tomography and audiovestibular testing were helpful in evaluating the severity of injury and guiding the surgical approach when necessary. Electroneurography was helpful in evaluating facial nerve function; however, documented disruption of the facial nerve canal in itself was considered an indication for surgical exploration. Other indications for surgical intervention included evidence of dural tear, vascular injury, and severe disruption of the external auditory canal.

Management of flap necrosis in cochlear implantation.

Skin flap complications are the most commonly reported problems in cochlear implant surgery when the anteriorly based C-shaped flap is used for the incision. If the prosthesis is exposed by flap necrosis, local skin flaps may be used to obtain coverage. Unfortunately, the long-term viability of such flaps may be compromised by the pressure exerted by the transmitter. Two cases of flap necrosis severe enough to expose the prosthesis have been successfully managed by relocating the device to a position superior to the auricle, under healthy skin. In one case the receiver was removed owing to infection and reimplanted at a later date. In this case, the electrode array was left in place at explantation in order to stent the cochlea. The surgical techniques and flap designs for this procedure are presented. No further surgical complications have developed in either case. The devices are performing well for both patients at this time. We have found relocation of the implant a useful technique in the management of major flap necrosis. This technique may also be useful to prevent flap necrosis should excessive flap thinning occur during the implant operation.

The use of gadolinium-enhanced magnetic resonance imaging to determine lesion site in traumatic facial paralysis.

Gadolinium-enhanced magnetic resonance imaging has been used to evaluate 20 patients with surgically confirmed facial nerve lesions. When the nerve could be seen, gadolinium-enhanced magnetic resonance imaging accurately revealed the lesion site as well as the known extent, which in some cases was not predicted by topognostic testing. This technique appears to provide accurate lesion-site testing and may have importance in surgical planning. Currently used topognostic tests of facial nerve function are frequently inaccurate and can only determine the most proximal lesion site when there are multiple or extensive lesions. The focal nerve enhancement seen in nerve injury, globally increased signal intensity within the temporal bone after trauma, and increased signal intensity within the dura after surgery can occasionally mask nerve lesions and may be confused with tumors.

Diagnosis and treatment of arachnoid cysts of the posterior fossa.

Arachnoid cysts of the posterior fossa are rare. When arachnoid cysts are encountered, the presenting symptoms are frequently otologic, with hearing loss and imbalance occurring commonly. Three cases are presented with a previously unreported otologic symptom, that of bilateral hearing loss, which in one case was fluctuant. None of the patients had the common symptoms of unilateral hearing loss and headache. With the advent of computed tomography and magnetic resonance imaging, these cysts may be readily identified, usually with diagnostic imaging alone. Unfortunately there is often a delay in diagnosis because of the vague and fleeting nature of the symptoms. Because no single diagnostic symptom pattern is able to characterize all cases, it is believed computed tomography or magnetic resonance imaging or both are indicated in patients with long-standing otologic complaints--even in the absence of unilateral symptoms. Treatment of posterior fossa arachnoid cysts primarily consists of surgical procedures designed to decompress the cyst. In this series, treatment with diuretics alone resulted in improvement of symptoms during several years of followup, with no evidence of enlargement of the cysts.

Pneumomediastinum secondary to a mandible fracture.

Pneumomediastinum may be produced by a simple facial fracture. It may also be a sign of other aerodigestive tract injuries, and this possibility should be ruled out. A minimal patient workup should include panendoscopy and soft tissue neck x-ray films in all cases. If no other injuries are found, resolution of the pneumomediastinum may be expected without further treatment.

MR imaging of facial nerve enhancement in Bell palsy or after temporal bone surgery.

The authors evaluated magnetic resonance (MR) images obtained with intravenously administered gadolinium in ten patients who had facial paralysis and no facial nerve tumor. In patients with either Bell palsy (four patients) or facial paralysis after temporal bone surgery (six patients), intratemporal facial nerve enhancement was seen. Facial nerve enhancement on MR images proved to be a nonspecific finding.

The singular canal: a valuable landmark in surgery of the internal auditory canal.

The singular canal transmits the posterior ampullary nerve between the inferior part of the internal auditory canal (IAC) and ampulla of the posterior semicircular canal. The anatomy of the singular canal was studied in temporal bone dissections, in surgical dissections, and in high-resolution computerized tomography scans. Measurements were taken for distances between the origin of the singular canal in the IAC, the porus acousticus, the vestibule, and posterior canal ampulla. The location and importance of the singular canal are demonstrated for retrosigmoid-IAC vestibular neurectomy, retrosigmoid acoustic neuroma surgery, and transcochlear cochleovestibular neurectomy. The main purpose for the use of the retrosigmoid approach to the internal auditory canal during vestibular neurectomy and excision of acoustic neuromas is preservation of hearing. A major concern when the contents of the internal auditory canal are exposed through this approach is fenestration of the labyrinth, which results in sensorineural hearing loss. In the retrosigmoid approach, the singular canal has been found to be a vital landmark in prevention of fenestration during surgery of the internal auditory canal.

Permanent middle ear aeration: long-term follow-up of transosseous ventilating tubes.

A technique for achieving permanent middle ear aeration by inserting a flanged silicone tube (SPAT) through a hole drilled in the external auditory canal was introduced in 1970. Since 1970, we have used the transosseous procedure in 36 patients (11%) of cases that required middle ear ventilation. The average length of time the transosseous SPAT functioned was 51 months (range 0-138). Best results were obtained in patients over 16 years of age, when chronic ear surgery was not performed simultaneously. Transient otorrhea occurred in 23% of cases. Forty-four percent of tubes became blocked and required removal or were extruded. No patient developed facial weakness, middle ear cholesteatoma, or persistent tympanic membrane perforation. In selected cases, the transosseous SPAT provides long-term middle ear aeration without the risk of permanent tympanic membrane perforation.

A comparison of retrosigmoid IAC, retrolabyrinthine, and middle fossa vestibular neurectomy for treatment of vertigo.

A new procedure, the retrosigmoid internal auditory canal (IAC) vestibular neurectomy has been developed and presented. It involves a 3-cm retrosigmoid craniotomy removing the posterior wall of the IAC to the singular canal, with transection of the superior vestibular nerve and posterior ampullary nerve. This produces a complete denervation of the vestibular labyrinth and preserves the patient's hearing. All ten patients with Meniere's disease had their vertigo cured. Hearing was preserved to within 11 dB of the preoperative pure tone average in 9 of 10 cases. There were no serious complications, no cases of facial paralysis, and no cases of total hearing loss. These results compare favorably with the MFVN and the RVN. The retrosigmoid IAC vestibular neurectomy is an important improvement in the evolution of vestibular neurectomy for the treatment of vertigo.

The unrecognized rotation of the vestibular and cochlear nerves from the labyrinth to the brain stem: its implications to surgery of the eighth cranial nerve.

The cochlear and vestibular nerves rotate 90 degrees from the inner ear to the brain stem. Most of the rotation occurs within the internal auditory canal (IAC); only minimal rotation occurs in the cerebellopontine (CP) angle. At the labyrinthine end of the IAC, the cochlear nerve--which at first lies anterior to the inferior vestibular nerve (saccular nerve)--rapidly fuses with the inferior vestibular nerve. It then rotates to become inferior as the nerves leave the porus acousticus. The cochleovestibular (C-V) cleavage plane lies in a superior-inferior direction in the lateral IAC and rotates to become anterior-posterior in the CP angle. In 25% of patients in whom no C-V cleavage plane can be seen, it is not possible to completely transect all vestibular fibers. The surgical implications are that the most complete vestibular neurectomy can be done only in the lateral IAC, the cochlear and inferior vestibular nerves, because of their intimate association, should not be separated in the mid-IAC, in order to prevent damage to the cochlear nerve, and to create a complete denervation of the vestibular labyrinth, only the posterior ampullary nerve along with the superior vestibular nerve should be transected.