Combined mastoid/middle cranial fossa repair of temporal bone encephalocele.

Temporal bone encephalocele (TBE) has become less common as the incidence of chronic mastoid infection and surgery for this condition has decreased. Due to its declining incidence, the diagnosis of TBE may be delayed and result in the development of serious complications such as cerebrospinal fluid leak, meningitis, epidural or subdural abscess. Six cases of large (>1 cm) TBE of diverse etiology are described. Two patients had suffered previous temporal bone fractures, two had had prior mastoidectomy, and two patients had long-standing chronic mastoiditis. Two patients had undergone prior unsuccessful transmastoid repair. All patients underwent successful tegmen-dural repair with autogenous fascia, bone, and/or cartilage, primarily via a combined mastoid-middle fossa approach. Accurate dural closure and support of intacranial contents are imperative to prevent recurrence. We find that permanent repair can best be performed with a combined mastoid middle cranial fassa approach.

Cochlear implants in children.

Cochlear implants allow the rehabilitation of children with severe to profound hearing loss. They are beneficial for not only postlingual children with hearing loss but also for children with congenital or prelingual hearing loss. Issues regarding cochlear implant candidacy and surgery are discussed. The results of cochlear implants in children and the complications related to cochlear implant surgery in children are reviewed.

Cochlear implants in children.

Cochlear implants are no longer considered new or experimental technology. Difficulty in evaluating the degree of hearing loss and response to traditional forms of amplification in young children makes pediatric cochlear implant candidacy a complex issue. Cochlear implantation and, in particular, pediatric cochlear implantation, requires a team commitment with contributions from surgeons, audiologists, speech pathologists, psychologists, and special educators. Elements discussed include assessment and candidacy issues, surgical technique, elements of a cochlear implant team, outcome assessment, and potential complications. The decision to perform pediatric cochlear implantation should not be undertaken without serious consideration to the enormous commitment required in both financial and personnel terms.

Tinnitus suppression following cochlear implantation. A multifactorial investigation.

The effects of cochlear implant on loudness, annoyance, daily duration, location, and residual inhibition of tinnitus were evaluated by a closed-ended, quantifiable questionnaire in 33 postlingually deafened patients who had received implants at the University of Michigan, Ann Arbor, between 1986 and 1990. Preoperative tinnitus was present in 85% of patients. A statistical comparison of preoperative vs postoperative loudness and annoyance indicated a significant reduction in both of these complaints postoperatively. Loudness and annoyance were significantly correlated, both preoperatively and postoperatively. Fifteen patients (54%) with preoperative tinnitus demonstrated a loudness decrease of 30% or more; 43% demonstrated an annoyance decrease of 30% or more; and 48% demonstrated a decrease of 30% or more in daily tinnitus duration. Patients who experienced a loudness or annoyance decrease of 30% or more after implantation demonstrated significantly higher preoperative levels of these complaints, suggesting that degree of tinnitus reduction after implantation may be related to preoperative loudness and annoyance levels. Contralateral tinnitus suppression was reported by 42% of patients. Residual inhibition ranging from 60 seconds to several hours was reported by 50% of patients, predominantly in the ear with the implant. Age, gender, cause of hearing loss, duration of tinnitus, cochlear implant usage, and time after implantation were not predictive of tinnitus suppression. Overall, the majority of the patients (74%) thought that their cochlear implant was helpful in tinnitus suppression, especially in the ear with the implant. Contralateral residual inhibition and tinnitus suppression suggest a central mechanism contributing to these phenomena.

Sudden hearing loss as the sole manifestation of neurosarcoidosis.

Sarcoidosis is a chronic, idiopathic granulomatous disease with frequent pulmonary, ocular, and lymphatic systemic manifestations. Central nervous system involvement is rare (1% to 5%), yet the most frequent presenting symptoms (48%) in patients with neurosarcoidosis are neurologic. Eighth cranial nerve abnormalities occur in 20% of these patients, typically in association with other cranial neuropathies or overt systemic disease. Isolated eighth nerve disease is very rare. We report two cases of neurosarcoidosis manifest as isolated, sudden onset sensorineural hearing loss, one of which had a cerebellopontine angle (CPA) granuloma that mimicked an acoustic neuroma. Both patients experienced marked steroid-induced hearing improvement that persisted after termination of therapy. Brainstem evoked response audiometry (BSER) abnormality persisted despite normalization of audiologic parameters. The implications for diagnosis and treatment of sarcoidosis-induced hearing loss are described. Neurosarcoidosis must be considered when evaluating patients with sudden hearing loss. Prompt steroid therapy offers hope for significant hearing recovery in these patients.

The infratemporal fossa approach to skull base surgery.

The infratemporal fossa approach, in conjunction with the application of microsurgical technique and improved perioperative care, has permitted significant advances in lateral skull base surgery. The glomus jugulare tumor is the prototypical neoplasm resected by this approach, although this technique can be applied to a host of additional benign and malignant lesions of the skull base. This approach entails identification and control of the cranial nerves and great vessels in the neck, anterior transposition of the facial nerve, and infralabyrinthine petrosectomy. Intracranial tumor extension and petrous carotid artery involvement remain limiting factors. Significant morbidity, particularly neurologic deficit and hemorrhage, may occur due tot the nature and location of lateral skull base tumors. Recent advances in preoperative embolization and temporary carotid artery balloon occlusion have advanced the limits of resection via the infratemporal fossa approach.

Selective non-surgical management of subperiosteal abscess of the orbit: computerized tomography and clinical course as indication for surgical drainage.

Subperiosteal abscess of the orbit (SPA) in childhood is an uncommon but serious sequela of sinusitis, with partial or complete visual loss as the most common complication. Traditional management of SPA has combined systemic antibiotics with immediate surgical drainage. The records of 120 children admitted from 1982-1986 with the diagnosis of periorbital or orbital cellulitis were reviewed. Ten cases of SPA were documented by CT scan (8%). Antecedent ethmoid sinusitis was present in all cases. Five SPA patients were managed with intravenous antibiotics and nasal decongestants alone. All had complete clinical and radiographic resolution without complication. The remaining 5 patients underwent surgical drainage. Two patients required immediate drainage due to total ophthalmoplegia upon presentation. One case of postoperative epidural abscess occurred one week after external fronto-ethmoidectomy among these two patients. The remaining 3 patients did not respond adequately to medical therapy alone and underwent surgical drainage without complication. Length of hospital stay in both medical and surgical groups was similar. We conclude that SPA can be safely managed by medical therapy alone in selected cases. Criteria for surgical intervention of documented SPA while on optimal medical therapy should include: worsening of visual acuity or ocular motility, or failure to improve clinically within 48 h. The presence of SPA alone should no longer be considered an absolute indication for surgery.

Aminoglycoside toxicity: pH dependent inhibition of ADH response.

The effect of aminoglycoside antibiotics on the response of the isolated toad urinary bladder to antidiuretic hormone (ADH) was investigated. Gentamicin and neomycin both acidify the serosal bathing solution and cause a dose-dependent inhibition of the hydroosmotic response to ADH, while streptomycin has minimal effect on media pH and causes no inhibition of the response to ADH. Detailed studies employing gentamicin indicate that acidification stimulates production of PGE2, a known inhibitor of the hydroosmotic response of the toad bladder to ADH. When media pH is rigidly controlled or PGE2 production is inhibited by indomethacin, the inhibitory effect of gentamicin on the response to ADH is ameliorated. These studies suggest that the defect in renal concentrating ability seen as part of aminoglycoside nephrotoxicity could be due, in part, to an acidification-induced, prostaglandin-mediated resistance to the action of ADH.

Markedly delayed postoperative malignant hyperthermia.

Malignant hyperthermia (MH) may be triggered by exposure to commonly employed anesthetic agents and muscle relaxants, and often manifests itself during the period of anesthesia. Delayed-onset MH occurring one to four hours postoperatively has been described in isolated case reports. A case of delayed-onset MH occurred 11 hours following routine tonsillectomy and adenoidectomy. The patient demonstrated tachypnea, tachycardia, hyperthermia, and metabolic acidosis. Prompt intravenous administration of dantrolene sodium was therapeutic. Serial serum creatine phosphokinase evaluation verified the diagnosis of MH. The implications of delayed-onset MH and the importance of preoperative screening for potentially susceptible individuals are discussed.

Laryngeal perichondritis and abscess.

Primary infection of the laryngeal cartilages has become rare in the antibiotic era. However, trauma, irradiation, a foreign body, or cancer may initiate the infection, particularly in the immunocompromised patient. We encountered three cases of perichondritis and abscess associated with airway intubation, nasogastric intubation, and external beam radiotherapy. Laryngeal perichondritis and abscess remain serious potential causes of laryngeal deformity and dysfunction.