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Biomedical subjects

H Silverstein

Publications and source records attributed to H Silverstein.

At least 55 records · Page 3Linked to original sources
PubMed1993

An algorithm for the management of acoustic neuromas regarding age, hearing, tumor size, and symptoms.

An algorithm has evolved for the management of patients with acoustic neuroma. Decisions as to surgery vs. observation, surgical approach, and whether hearing preservation should be attempted depend on age, patient symptoms, size of the tumor, residual hearing, and degree of facial nerve involvement at the time of surgery. Conservative management is used for patients over 65 years of age. This consists of observation or subtotal resection through a translabyrinthine approach, depending on the absence or presence of brainstem signs or symptoms. In patients under 65 years of age, hearing preservation is attempted through the retrosigmoid approach in tumors 1.5 cm or less if pure-tone average is less than 30 dB and the discrimination score is greater than 70%. The translabyrinthine approach is our preferred approach for tumors of any size when hearing is not serviceable. A near-total excision is performed when the facial nerve cannot be separated from the tumor. The rationale for this algorithm in the management of 130 cases of acoustic neuroma over the past 17 years is presented.

Adult↗
PubMed1993

A comparison of growth rates of acoustic neuromas: nonsurgical patients vs. subtotal resection.

A conservative approach to the management of acoustic neuromas in elderly patients has been used since 1971. Elderly patients without symptoms of brain stem compression are initially treated by observation and yearly radiographic imaging. A translabyrinthine radical-subtotal resection is performed if brain stem compression is present or if tumor is growing rapidly. Twenty-three patients, ages 65 to 86 years, had initial nonsurgical management of their tumors. Growth rates could be determined for 16 patients. Thirteen patients not requiring surgery had an average tumor growth rate of 0.6 mm/yr. Three patients with an average growth rate of 6.8 mm/yr eventually required surgery. No patient whose tumor was < 15 mm at initial evaluation has experienced brain stem symptoms or demonstrated rapid tumor growth. Twenty-four patients ages 65 to 86 years underwent planned subtotal tumor excision. Eighteen patients followed postoperatively for more than 1 year demonstrated an average rate of regrowth of tumor of 0.7 mm/yr.

Aged↗
PubMed1993

Middle ear air injection after chronic ear surgery.

In the early period after chronic ear surgery, the reasons for conductive hearing loss may be difficult to determine. Patients who cannot autoinflate the middle ear after 3 weeks, or who have a negative Rinne test result with the 512 Hz tuning fork, are treated with a transtympanic injection of 0.5 cc of air with a 27-gauge needle and tuberculin syringe. This represents 20% of patients who had chronic ear surgery. Results show that hearing may be immediately improved, the sensation of pressure in the ear may be reduced, and fluid may be cleared from the middle ear. Other benefits may include the release of adhesions. The surgeon is better able to assess the thickness of the graft, and the status of the ossicular chain reconstruction can be determined. There have been no complications of middle ear infection or failure of the micropuncture site to heal. In our practice, middle ear air injection is a routine procedure in patients with inadequate eustachian tube function after chronic ear surgery. This report describes the results of 100 patients over 14 years who received middle ear air injections after chronic ear surgery compared with a control group of 100 patients who did not meet the criteria for requiring air injection. Hearing was immediately improved in 74% of patients as determined by Rinne testing. Audiograms were performed in 25 of these patients, documenting a mean improvement in pure-tone average of 16 dB. The long-term hearing results in patients undergoing air injection, who by definition had evidence of poor eustachian tube function, are similar to the results in the control group.(ABSTRACT TRUNCATED AT 250 WORDS)

Air↗
PubMed1993

Compatibility of the argon and KTP lasers with middle ear implants.

Visible-spectrum lasers (argon, KTP) are becoming common tools in otology. Concern over transmission of disease by homograft tissue has focused attention on synthetic materials such as Silastic, Polycel, hydroxylapatite, and Teflon. This study sought to determine the effects of argon and KTP lasers on materials used in stapes and chronic ear surgery. Silastic sheeting, hydroxylapatite and polycel total ossicular replacement prostheses (TORPs) and partial ossicular replacement prostheses (PORPs), and platinum wire/Teflon stapes prostheses were exposed to argon and KTP laser energy at clinical power settings. Effects of the two lasers were similar. The presence of pigment (char or blood) was necessary to produce any effect. Silastic transmitted energy to underlying material. Hydroxylapatite cracked and shattered. Polycel vaporized and melted, as did Teflon. Clinical implications of these interactions on primary and revision otologic surgeries will be discussed.

Argon↗
PubMed1993

Bipolar cochlear nerve recording technique: a preliminary report.

To preserve hearing during vestibular neurectomy and acoustic neuroma removal, the cochlear nerve must be identified. Present techniques, including monitoring eighth nerve action potentials, help the surgeon identify those maneuvers that increase the risk of nerve injury but do not help in the anatomic identification of the cochlear nerve or the cochlear-vestibular cleavage plane. The purpose of this study was to demonstrate an electrophysiologic method of identifying the cochlear portion of the eighth cranial nerve. A flush-tipped, bipolar electrode recording probe was used to directly record responses to monaural click stimuli from the cochlear nerve but not from surrounding tissue. It was also used to delineate the cochlear-vestibular cleavage plane. Stimulus intensity levels over 25 dB sensation level tended to reduce the accuracy of nerve identification, and lower levels prolonged recording time. This technique and its application to posterior fossa surgery is discussed.

Adolescent↗
PubMed1993

Intraoperative facial nerve monitoring in acoustic neuroma surgery.

Intraoperative facial nerve monitoring simultaneously using electromyography and mechanical pressure sensors is being used in retrosigmoid and translabyrinthine approaches for acoustic neuroma resection. Insulated electrified microsurgical instruments and air drills are used to stimulate the facial nerve with a pulsed, constant current through bone and tumor, before the facial nerve is visually encountered. Electrical stimulation is used to help locate the facial nerve, map the course of the facial nerve within tumor, warn the surgeon of unexpected facial nerve locations, and help predict facial nerve function postoperatively. In 57 unmonitored cases a House-Brackmann (H-B) grade I or II result was obtained in 77 percent of small, 81 percent of medium, and 60 percent of large tumors. In 64 monitored cases H-B grade I or II was obtained in 88 percent of small, 79 percent of medium, and 90 percent of large tumors. Overall, facial nerve outcomes were better after monitored procedures (p < 0.02). A modified H-B classification for acute facial nerve injury is introduced to grade facial weakness immediately postoperatively and until function is stable at 1 year. In the unmonitored group there were five (9%) cases with a complete facial paralysis, facial nerve intact (i.e., acute H-B grade VIA) and seven (13%) cases with the facial nerve transected (i.e., acute H-B grade VIB). In the monitored group there were five (8%) acute H-B grade VIA and two (3%) acute H-B grade VIB results. In the unmonitored group of large tumors, there were statistically more patients with an acute H-B grade VIB result (p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Vestibular neurectomy in the United States--1990.

During the last decade, vestibular neurectomy has become a more frequently performed procedure to cure symptoms of inner ear vertigo while preserving hearing. In an effort to determine the results of vestibular neurectomy across the country, a questionnaire was prepared and sent to the 350 members of the American Otologic Society and the American Neurotology Society. Results of that survey indicated that 2,820 vestibular neurectomy procedures were performed by 58 surgeons. Ninety-two percent (2,590 cases) were performed through the posterior fossa approach. Of these, 1149 cases (44%) were through the retrolabyrinthine approach, 940 cases (36%) were through the retrosigmoid approach, 307 cases (12%) were through the combined retrolabyrinthine-retrosigmoid approach, and 194 cases (8%) were unspecified as to which posterior fossa approach was used. The remaining 230 cases (8%) were through the middle fossa approach. Sectioning of the vestibular nerve was done by the otologist in 58 percent of cases, by the neurosurgeon in 12 percent, and by either surgeon in 30 percent. Classic Meniere's disease, the most common indication for vestibular neurectomy, resulted in the best cure rate of 91 percent. Other inner ear diseases such as traumatic labyrinthitis and vestibular neuronitis had a lower cure rate of 74 to 81 percent. Hearing was preserved to within 20 dB of the preoperative pure-tone thresholds in 87 percent. There were no deaths, 11 cases of meningitis and 16 cases of facial paralysis, 15 of which occurred after middle fossa surgery, representing a 7 percent incidence of facial paralysis after middle fossa surgery. Eleven of the 15 cases resulted in permanent paralysis and four in temporary paralysis.(ABSTRACT TRUNCATED AT 250 WORDS)

Humans↗
PubMed1991

Rapid protein test for perilymph fistula.

The existence of a perilymph fistula may be difficult to prove preoperatively or at surgery, except in obvious cases in which perilymph can be seen coming out of the inner ear around the stapes footplate or round window niche. Some surgeons doubt the common occurrence of spontaneous perilymph fistula. Most surgeons believe that a perilymph fistula is rare and is produced by some type of trauma and pressure change to the inner ear fluids. Analysis of fluid collected from the oval window area and round window niche may be a great help in confirming or disproving the diagnosis of perilymph fistula. After a myringotomy or tympanotomy, fluid collected in micropipets from the oval window or round window area is analyzed for protein concentration, using rapid protein indicator paper. The original technique was developed in the 1960's to analyze the inner ear fluid as a diagnostic procedure (i.e., diagnostic labyrinthotomy) in acoustic neuroma suspects. Normal perilymph has a protein content of approximately 200 mg %, which turns the indicator paper light green, whereas serum or transudate has a protein content of approximately 7000 mg %, which turns the indicator paper dark green. The protein concentration is determined by comparing the color of the indicator paper with the color developed by known protein standards. A middle ear tap may help avoid negative middle ear exploration for perilymph fistula and helps document the presence or absence of perilymph after the exploration.

Cochlear Diseases↗
PubMed1991

Intraoperative facial nerve monitoring.

Facial nerve monitoring is one of the most exciting innovations in otologic surgery in the past decade. Intraoperative monitoring has been shown to reduce the probability of iatrogenic injury to the facial nerve during surgery. It saves surgical time and reduces the anxiety level of both patients and surgeons. There are several reasons to use facial nerve monitoring: The surgeon nerve knows when it will be needed in a particular case, the operating room personnel become familiar with the equipment, and the surgeon learns how to interpret the sounds produced by the monitor and how to correlate them with surgical manipulations around the facial nerve. Facial nerve monitoring has added another dimension of safety to otologic and neurotologic surgery and has reduced the incidence of facial weakness or paralysis in the authors' surgical practice.

Facial Nerve↗
PubMed1991

Bilateral Menière's disease in surgical versus nonsurgical patients.

In patients with Menière's disease, the possibility of developing Menière's disease in the uninvolved ear is of great concern. In this study, the incidence of bilateral Menière's disease (BMD) in medically treated patients was found to be 17 percent, while in surgically treated patients it was significantly lower, 5.9 percent (p less than 0.01). The incidence of BMD for each surgical procedure was as follows: 9 percent after endolymphatic subarachnoid shunt (n = 101), 7 percent after cochleovestibular neurectomy (n = 100), 6 percent after cochleosacculotomy (n = 18), and 0 percent after vestibular nerve section (n = 73). The average duration of disease prior to surgery was 6.3 years. Seventy-two percent of the patients who developed BMD did so within 5 years of the onset of their symptoms. Proper patient selection is the most likely explanation for the low incidence of BMD among surgically treated patients.

Adolescent↗
PubMed1990

An evolution of approach in vestibular neurectomy.

Since introducing the retrolabyrinthine vestibular neurectomy in 1978, we have performed 78 procedures with good results. In 1985 we introduced the retrosigmoid-IAC vestibular neurectomy, which allows a more complete transection of the vestibular nerves within the internal auditory canal (IAC). Vertigo control has been excellent; however, in 75% of patients, postoperative headaches have been a significant problem. In 1987, the best aspects of the two procedures were incorporated and the combined retrolab-retrosigmoid vestibular neurectomy was developed. The procedure is similar to the RVN in that all bone covering the lateral venous sinus is removed. It differs from the RVN in that a limited mastoidectomy is performed and the dura is opened just behind the LVS. The LVS is retracted forward, exposing the cerebellopontine angle. This allows the surgeon the option to section the vestibular nerve in either the CP angle or the IAC, depending upon the presence or absence of a cochieovestibular cleavage plane in the CP angle. The results have been good and the incidence of headache has been reduced to 10%. The technique, results, and complications are reported here.

Ear, Inner↗