Joseph C. Farmer

Transmission of cerebrospinal fluid pressure via the cochlear aqueduct and endolymphatic sac.

The concept of perilymphatic and endolymphatic pressure balance is generally linked to the theory that the endolymphatic sac transmits cerebrospinal fluid (CSF) pressure changes to the endolymph to equalize CSF pressure changes transmitted to the perilymph via the cochlear aqueduct. This theory, and the significance of other mechanisms of CSF pressure influence on the labyrinth, were evaluated experimentally. Continuous measurements of perilymphatic, CSF, venous, and arterial pressures were performed on cats with the cochlear aqueduct patent or obstructed and the inferior cochlear vein intact or occluded. Intracranial pressure changes were induced by subarachnoid infusion of artificial CSF in live and dead animals. With the cochlear aqueduct patent, CSF pressure changes were transmitted to the perilymph without any significant dampening or time lag. With the cochlear aqueduct obstructed, CSF pressure changes induced significantly lower and delayed changes in perilymphatic pressure. Similar results were obtained whether the animals were alive or dead and the cochlear vein intact or blocked. This indicated a passive mechanism not induced by changes in labyrinthine fluid production or blood flow. Long-standing, stable elevation of CSF pressure with the cochlear aqueduct blocked induced a slowly increasing perilymphatic pressure, always stabilizing at a pressure rise significantly less than that of CSF. The results do not suggest any major pressure transfer via perineural or perivascular routes. The endolymphatic sac is postulated to mediate a reduced and delayed transfer of increased intracranial pressure to the labyrinth.

Hyperbaric Oxygen Therapy for Laryngeal Radionecrosis

Radionecrosis of the larynx is a debilitating disease associated with pain, dysphagia, respiratory obstruction, and, in some cases, the need for laryngectomy. Persistent poor wound healing can lead to death. A series of eight patients with advanced (grades III and IV, Chandler classification) radionecrosis of the larynx treated with adjunctive hyperbaric oxygen therapy is presented. Signs and symptoms of radionecrosis were dramatically ameliorated in seven of eight patients, while one patient, despite subjective improvement, eventually required laryngectomy. There were no deaths. These results are compared to previous series on radionecrosis of the larynx in which hyperbaric oxygen was not used. This series indicates that hyperbaric oxygen therapy is a useful and effective adjunctive treatment modality in the management of laryngeal radionecrosis.

Comparative studies of speech processing strategies for cochlear implants

A wide variety of speech processing strategies for multichannel auditory prostheses were compared in studies of two patients implanted with the UCSF electrode array. Each strategy was evaluated using tests of vowel and consonant confusions, with and without lipreading. Included among the strategies were the compressed analog processor of the present UCSF/Storz prosthesis and a group of interleaved pulses processors in which the amplitudes of nonsimultaneous pulses code the spectral variations of speech. For these patients, each with indications of poor nerve survival, test scores were significantly higher with the interleaved pulses processors. We believe this superior performance was a result of 1. the substantial release from channel interactions provided by nonsimultaneous stimuli and 2. a fast enough rotation among the channels to support adequate temporal and spectral resolution of perceived speech sounds.

Treatment of radiation-induced tissue injury by hyperbaric oxygen

Hyperbaric oxygen therapy appears to be a beneficial adjunctive treatment modality in the management of radionecrosis of bone and soft tissue in the head and neck. The mechanism of such wound healing enhancement appears to be related to oxygen stimulation of fibroblastic activity and neovasculation. In this pilot study, involving 13 cases of refractory mandibular radionecrosis treated with hyperbaric oxygen, complete healing of soft tissue disease with covering of exposed bone has been noted in seven cases 11 to 27 months posttreatment; transient healing was seen in three cases; moderate to marked improvement in soft tissue disease has been noted in three cases. Pain relief was marked in six cases, moderate in four cases, and slight in one case of the 11 patients with significant pretreatment pain. Radiographic improvement was slight to moderate in ten cases. Four of the five patients with pathologic fractures developed a firm fibrous union of the mandibular segments during or shortly after treatment. Three additional cases of head and neck radionecrosis of other sites have noted significant improvement in their lesions during treatment. Three other patients with radionecrosis of the foot, hip, and vagina have also been treated with good results only in the vaginal case. None of the 19 patients treated with hyperbaric oxygen developed persistent or significant complications.

Laryngeal Radionecrosis and Hyperbaric Oxygen Therapy: Report of 18 Cases and Review of the Literature

Laryngeal radionecrosis is a difficult late complication of radiotherapy. It is associated with hoarseness, edema, pain, weight loss, and upper airway obstruction. The medical treatment options are limited, and in severe cases, the patient may require tracheostomy or laryngectomy. We report clinical results in 18 patients treated with adjunctive hyperbaric oxygen (HBO) therapy for severe radionecrosis of the larynx. Of these 18 patients, 2 had grade 3 and 16 had grade 4 radionecrosis. The patients received a mean number of 41 HBO treatments (range, 6 to 80) at 2 atmospheres absolute for 2 hours, twice a day, 6 days a week. Thirteen patients (72.2%) had a major improvement after HBO therapy, and none of them required total laryngectomy. All patients preserved their voice and deglutition in good or normal condition. Five patients (27.8%) failed to have a good response to HBO and underwent total laryngectomy. One of these patients had local recurrence of his cancer 4 months later, and the other 3 had significant concurrent medical problems. The remaining patient received only 6 HBO treatments because of emergency heart surgery. These encouraging results are comparable to those of smaller previous studies suggesting that HBO has a beneficial effect in the management of advanced laryngeal radionecrosis.

Pressure Gradients Affecting the Labyrinth during Hypobaric Pressure Experimental Study

Hypobaric effects on the perilymph pressure were investigated in 18 cats. The perilymph, tympanic cavity, cerebrospinal fluid, and systemic and ambient pressure changes were continuously recorded relative to the atmospheric pressure. The pressure equilibration of the eustachian tube and the cochlear aqueduct was studied, as well as the effects of blocking these channels. During ascent, the physiologic opening of the eustachian tube reduced the pressure gradients across the tympanic membrane. The patent cochlear aqueduct equilibrated perilymph pressure to cerebrospinal fluid compartment levels with a considerable pressure gradient across the oval and round windows. With the aqueduct blocked, the pressure decrease within the labyrinth and tympanic cavities was limited, resulting in large pressure gradients toward the chamber and the cerebrospinal fluid compartments, respectively. We conclude that closed cavities with limited pressure release capacities are the cause of the pressure gradients. The strain exerted by these pressure gradients is potentially harmful to the ear.

Submaxillary gland tumors

Tumors arise much less frequently in the submaxillary gland than in the parotid gland; however, the incidence of malignancy is higher in submaxillary neoplasms. The records of 50 patients with submaxillary gland tumors were reviewed and the findings compared with those of other recent series. Malignant tumors of the submaxillary gland were found to behave aggressively, and poor results were obtained in treating these lesions, especially when recurrences were present. It is felt that a planned approach consisting of adequate initial resection would lead to improved results.

Giant cell arteritis and polymyalgia rheumatica: review for the otolaryngologist

Patients suspected of giant cell arteritis or polymyalgia rheumatica are often referred to the otolaryngologist for temporal artery biopsy. These patients may initially present to the otolaryngologist with symptoms referable to the head and neck. a comprehensive review of these two interrelated disorders is provided, with emphasis on head and neck manifestations and features of obtaining the temporal artery biopsy specimen.

Septoplasty: A Study in Hemostasis

William C. Smith and Terry L. Fry, University of North Carolina, Chapel Hill, reported a prospective study comparing blood loss during septoplasty under local vs general anesthesia. This report, presented Jan 16, 1988, at the Southern Section meeting of the Triological Society, Birmingham, Ala, presented data that indicated a fourfold increase in blood loss when general anesthesia was utilized; however, the data were not statistically significant. The operating surgeon and the patient were allowed to select the anesthesia without being randomly assigned to either anesthetic technique. Patients with aspirin use, coagulation disorders, other procedures, or repeated septal surgery were excluded. The increased blood loss with general anesthesia was not found to be related to the performance of submucosal resections of the inferior turbinates at the time of surgery, and occurred despite equal uses of local anesthetics with each technique. Associated subjective differences in bleeding and operative exposure were observed by