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Biomedical subjects

J M Kartush

Publications and source records attributed to J M Kartush.

At least 19 recordsLinked to original sources
PubMed1992

Patterns of vestibular function following vestibular nerve section.

Bithermal caloric irrigations, low-frequency rotational chair stimulation, and posturography were performed on 20 patients before and after vestibular nerve section. Twelve patients demonstrated acute postoperative spontaneous nystagmus and rotational vestibulo-ocular reflex (VOR) asymmetry. Eight patients demonstrated minimal acute postoperative spontaneous nystagmus and VOR asymmetry. Four patients had suppression of all vestibular function characterized by an absent contralateral caloric response, low VOR gain, and falls on posturography when required to rely solely on vestibular input to maintain posture. Four patients had a severe preoperative vestibular loss and no acute change in vestibular function following surgery. Over time, 5 patients continued to manifest elevated spontaneous nystagmus, 2 patients manifested a persistent rotational VOR asymmetry, and 5 patients exhibited a return of caloric function in the operated ear. It is suggested that multiple clinical factors contributed to the variable vestibular responses demonstrated in this study.

Adult↗
PubMed1992

Facial nerve outcome in acoustic neuroma surgery.

Patients consider facial paralysis the most concerning sequelae following acoustic tumor resection. Surgical and anesthetic refinements have lowered operative mortality to allow the surgeon to focus on preserving facial nerve function. Tumor size, microsurgical technique, and intraoperative monitoring are the most important factors that define the risk of postoperative facial paralysis. A protocol for uniform surgical reporting is proposed.

Facial Nerve↗
PubMed1991

Electromagnetic semi-implantable hearing device: phase I. Clinical trials.

Conventional hearing aids have improved significantly in recent years; however, amplification of sound within the external auditory canal creates a number of intrinsic problems, including acoustic feedback and the need for a tight ear mold to increase usable gain. Nonacoustic alternatives which could obviate these encumbrances have not become practical due to inefficient coupling (piezoelectric techniques) or unfeasible power requirements (electromagnetic techniques). Recent technical advances, however, prompted a major clinical investigation of a new electromagnetic, semi-implantable hearing device. This study presents the details of clinical phase I, in which an electromagnetic driver was coupled with a target magnet temporarily affixed onto the lateral surface of the malleus of six hearing aid users with sensorineural losses. The results indicate that the electromagnetic hearing device provides sufficient gain and output characteristics to benefit individuals with sensorineural hearing loss. Significant improvements compared to conventional hearing aids were noted in pure-tone testing and, to a lesser degree, in speech discrimination. Subjective responses were quite favorable, indicating that the electromagnetic hearing device 1. produces no acoustic feedback; 2. works well in noisy environments; and 3. provides a more quiet, natural sound than patients' conventional hearing aids. These favorable results led to phase II of the project, in which patients with surgically amendable mixed hearing losses were implanted with the target magnet incorporated within a hydroxyapatite ossicular prosthesis. The results of this second-stage investigation were also encouraging and will be reported separately.

Acoustics↗
PubMed1991

Comparison of computerized tomography and magnetic resonance imaging for the postoperative assessment of residual acoustic tumor.

Ten patients with surgically confirmed residual cerebellopontine angle neuromas, imaged by both computerized tomography (CT) with iodine contrast and magnetic resonance (MR) with and without gadolinium enhancement, are reviewed to identify the strengths and limitations of MR as compared with CT imaging. MR imaging offers superior anatomic resolution in multiple imaging planes without ionizing radiation, but it is expensive and has adverse effects on some patients. CT imaging offers good anatomic resolution, but in only one or two planes. CT is both less expensive and generally well tolerated, but allergy to the iodine contrast is not uncommon. The cases presented demonstrate the adequacy of CT imaging of residual tumor. However, in some cases MR imaging provided important additional detail. MR imaging also demonstrated postoperative changes within the brain stem and cerebellum. In our experience, CT imaging remains a satisfactory, unambiguous approach to the assessment of known postoperative residual cerebellopontine angle neuromas. MR imaging provides superior resolution, however, and should be used when better definition of tumor detail is needed for management decisions or when multiple follow-up scans are anticipated, so that the exposure to ionizing radiation is limited. MR is also useful to investigate postoperative neurologic dysfunction. Postoperative changes and residual tumors are more difficult to interpret on MR than on CT. Guidelines are proposed to help distinguish residual tumor from postoperative changes and scarring.

Adult↗
PubMed1991

Clinical assessment of postural stability following vestibular nerve section.

Little is known about the recovery of postural control in patients following acute vestibular loss. This paper reports on the results of moving-platform posturography to assess the recovery of postural stability in 24 patients following vestibular nerve section. Posturography was abnormal prior to surgery in 17% of the patients. Seven days following surgery, 44% of the patients demonstrated vestibular deficit patterns, while 56% of the patients had normal posturography. Posturography was normal in all patients 1 month following surgery. Abnormal posturography was subsequently noted in 21% of the patients between 3 and 20 months following surgery. Each of the patients with abnormal preoperative posturography subsequently demonstrated abnormal late postoperative posturography. These results suggest that perioperative posturography may be useful in the evaluation and counseling of patients considering ablative vestibular surgery.

Adult↗
PubMed1991

Testing facial nerve function.

A variety of facial nerve tests are now available. These tests can aid the clinician in discerning the site of lesion, estimating prognosis, assessing evidence of neoplastic or infectious involvement, and assisting in intraoperative facial monitoring.

Electrodiagnosis↗
PubMed1990

Early gold weight eyelid implantation for facial paralysis.

Facial paralysis can result in serious keratopathy because of corneal exposure and inadequate lacrimation. Thirty-seven patients underwent thirty-eight gold weight upper lid implants to rehabilitate paralysis of the eyelid from various causes. When indicated, implantation was combined with lower lid ectropion repair, medial canthoplasty or brow lift. Because of encouraging results in patients with longstanding facial paralysis, "early" implantation (within 1 month of paralysis) was offered to patients with severe lagophthalmos in whom (1) a severe neural injury was documented at the time of transtemporal surgery or (2) delayed, incomplete return of function was expected. Gold weight implantation resulted in excellent eyelid closure, protection, and cosmesis. There were no infections or extrusions. Lagophthalmos and exposure keratitis resolved or were significantly improved in all patients, and most were able to dispense with eyedrops and salves. Visual acuity improved in 95% of patients--a benefit even those without preoperative keratitis often achieved. A mild worsening of one patient's pre-existing astigmatism developed, which resolved after reimplantation with a lighter weight. The implant is easily removed from those patients who, having undergone early implantation, eventually recover adequate function. Gold weight loading has become our procedure of choice for eyelid rehabilitation.

Adolescent↗
PubMed1990

Promontory stimulation following labyrinthectomy: implications for cochlear implantation.

Transtympanic electric promontory stimulation is a psychoacoustic test used to assess residual acoustic neurons in profound sensorineural hearing loss. The test was performed in six patients who had previously undergone transmastoid (N = 5) or transcanal-oval window (N = 1) labyrinthectomy as a means of determining the feasibility of future cochlear implantation. Four patients had unilateral Meniere's disease, one had labyrinthitis, and one had delayed onset vertigo. All patients perceived a definite auditory sensation in the labyrinthectomized ear during stimulation. The results of threshold, dynamic range, and difference limen testing were similar to those obtained during preoperative stimulation of cochlear implant candidates (N = 12) who subsequently became successful users. There was no evidence of response degradations as the time following labyrinthectomy increased. The results of this study suggest the possibility of successful cochlear implantation following labyrinthectomy. Supporting histologic data are reviewed.

Acoustic Stimulation↗
PubMed1989

Total facial nerve decompression for recurrent facial paralysis: an update.

Recurrent facial paralysis (RFP) is a rare disorder that in some individuals may lead to worsening sequelae. Melkersson-Rosenthal syndrome is a variant of RFP that is associated with recurrent facial edema. In the past, decompression of the mastoid segment of the facial nerve has not been successful in preventing recurrences. In 1981 we began performing total facial nerve decompression for RFP and in 1986 reported its efficacy in one patient with Melkersson-Rosenthal syndrome and in another in whom both nerves were decompressed for alternating bilateral paralysis. An additional four cases with 3 to 8 years of followup demonstrate no recurrences in any patient. Total facial nerve decompression for RFP in selected patients appears efficacious in preventing recurrences. Decompression will remain investigational until further followup is obtained. Furthermore, its salutary effect should not be extrapolated to Bell's palsy without further study.

Adolescent↗
PubMed1989

Electroneurography and intraoperative facial monitoring in contemporary neurotology.

Electrodiagnostic testing of the facial nerve has evolved beyond prognostic and topognostic testing to include preoperative assessment and intraoperative monitoring. The state of the art in facial nerve testing is herein reviewed. Electroneurography is described as a means of preoperative assessment to detect subclinical neural degeneration for temporal bone tumors, malignant external otitis, and recurring facial paralysis. Techniques of intraoperative facial nerve monitoring are presented with clinical correlation of the facial evoked responses. Finally, recent advances in electrodiagnostic testing, including antidromic recording and transtemporal magnetic stimulation of the facial nerve, are discussed.

Electrodiagnosis↗
PubMed1989

Magnetic stimulation of the facial nerve.

Electrical testing of the facial nerve has evolved into an important means of assessing neural injury. However, the inability to stimulate the intratemporal facial nerve electrically results in a delay in diagnosis, because axonal degeneration must progress distal to the stylomastoid foramen before testing can be meaningful. To circumvent this problem, we began an investigation of magnetic stimulation of the facial nerve, because pulsed magnetic fields can pass unattenuated through all body structures, including bone. Normal volunteers and one patient with acute facial paralysis were studied with both magnetic and electric stimulation of the facial nerve. The results indicate that (1) magnetic stimulation was more comfortable because high current levels were not required at the skin surface to assure indepth stimulation, (2) magnetic and electric stimulation of the extratemporal facial nerve resulted in nearly identical compound muscle action potentials, indicating that the sites and mechanisms of neural depolarization are similar, and (3) transtemporal magnetic stimulation appears to allow depolarization of the proximal intratemporal nerve. These preliminary results are encouraging and indicate that magnetic stimulation of the facial nerve warrants further investigation.

Action Potentials↗
PubMed1988

Use of bacitracin for neurotologic surgery.

Wound infection, cerebrospinal fluid leak, and meningitis are serious potential complications of neurotologic procedures that transgress the posterior cranial fossa dura. A study of 236 patients was made to determine the effect of perioperative intravenous antibiotics and topical bacitracin irrigation on the incidence of these complications. Of the 236 patients, 170 (72%) underwent translabyrinthine resection of acoustic tumors, while 66 (28%) underwent retrolabyrinthine vestibular nerve section. Patients were divided into four groups: those who received no antibiotics, those who received perioperative intravenous antibiotics only, those who received topical bacitracin irrigation only, and those who received a combination of perioperative intravenous antibiotics and topical bacitracin irrigation. There were no untoward effects of either perioperative intravenous antibiotics or topical bacitracin. The results indicate that bacitracin irrigation reduced the incidence of wound infection from 9% to 2% (p less than 0.05); of cerebrospinal fluid leak from 12% to 5% (p less than 0.04); and of all targeted complications combined from 22% to 9% (p less than 0.006). Furthermore, the topical bacitracin irrigation only group showed a statistically significant reduction in wound infections compared to the perioperative intravenous antibiotic only group (p less than 0.02). The incidence of meningitis was statistically unaffected by any of our treatment protocols.

Bacitracin↗