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Biomedical subjects

J M Kartush

Publications and source records attributed to J M Kartush.

At least 37 records · Page 2Linked to original sources
PubMed1995

Use of intraoperative neuromonitoring to prevent orbital complications in ethmoid sinus surgery.

Orbital injury is one of the most serious complications in sinus surgery. Although these injuries are generally infrequent, there is a considerable increased risk for orbital complications during procedures in which anatomic landmarks are distorted because of the severity of disease or prior surgery. Currently there are no methods to detect early defects in the lamina papyracea or to prevent continued resection until orbital fat or periorbita is seen. Thirteen New Zealand white rabbits were studied by use of a nerve monitor to identify the periorbita and orbital fat in surgically created lamina defects. Evoked potentials were measured at the medial orbit when the lamina papyracea, periorbita, and orbital fat were stimulated at current intensities ranging from 0.25 to 1.00 mA. Stimulation of the lamina at 0.8 and 1.0 mA resulted in response amplitudes that were significantly lower compared with those of periorbita stimulation (means at 1 mA, 38.26 microV vs. 117.85 microV; p < 0.01). Stimulation of the orbital fat also resulted in higher potentials (mean, 59.47 microV) than those of the lamina papyracea (mean, 38.26 microV) but did not reach statistical significance. The statistically significant difference in response amplitudes between the lamina papyracea and the periorbita indicate that intraoperative monitoring may be useful in identifying early lamina defects, which could in turn reduce the risk of orbital injury during sinus surgery.

Animals↗
PubMed1995

Posterior semicircular canal occlusion for benign paroxysmal positional vertigo--CO2 laser-assisted technique: preliminary results.

Benign paroxysmal positional vertigo (BPPV) is a common vestibular end-organ disorder that in the majority of patients resolves with conservative management. In the occasional patient who has unremitting BPPV despite conservative treatment, posterior semicircular canal occlusion (PCO) may be effective in eliminating symptoms. In an attempt to minimize the risk of hearing loss, a modified procedure was developed that uses the CO2 laser to shrink the membranous vestibular posterior semicircular canal prior to mechanically plugging the canal. Preliminary results of this CO2 laser-assisted occlusion technique used in four patients are presented.

Aged↗
PubMed1995

Electromagnetic ossicular augmentation device.

Conventional hearing aids have a number of limitations inherent to amplifying sound in the narrow confines of the external auditory canal. Disadvantages include acoustic feedback, poor fidelity, and the stigmata of aging. Since 1986, Michigan Ear Institute and Smith and Nephew Richards Company have been investigating the feasibility of a new device that converts sound to an electromagnetic field. The efficacy and safety of electromagnetic-induced hearing was sufficient enough to have the Federal Food and Drug Administration approve a pilot study of ten patients with a sensorineural hearing loss in whom a target magnet is implanted beneath the tympanic membrane. A status report of this study and a review of our preceeding investigations are presented in this article.

Audiometry, Pure-Tone↗
PubMed1995

Meatal facial nerve decompression in acoustic neuroma resection.

Delayed facial palsy occurs after approximately 15% of acoustic neuroma resections. Whereas in most cases facial nerve function recovers satisfactorily, in about 12% of cases delayed facial palsy may have a poor functional recovery. The fate of facial nerve function was studied in 55 consecutive translabyrinthine acoustic neuroma resections, 23 of whom underwent meatal facial nerve decompression (MFND) at the time of tumor resection. The facial nerve results also were reviewed in 19 middle cranial fossa resections, of whom 14 underwent MFND. There was a bimodal distribution of the delayed palsies, with one group having the onset of palsy within hours to 2 days after surgery and the second group having onset of palsy up to 17 days after surgery. The poorest recoveries were seen in the first group. Although the effect was not statistically significant due to the small sample size, the chance of facial weakness in patients who underwent MFND after translabyrinthine surgery was about 40% less than in those who did not undergo decompression. The apparent protective effect of MFND was increased when the confounding factors of tumor size and degree of resection were taken into account, although the effect was not statistically significant. The duration of palsy was shorter and ultimate recovery better among the patients who underwent facial nerve decompression than in those who did not. Of the translabyrinthine patients who underwent MFND, 100% had House-Brackmann grade I-II function at 2 years, whereas 87% of patients who did not have MFND had grade I-II function and 13% had grade III-IV function. Without MFND, 57% of translabyrinthine patients whose onset of facial palsy was within 2 days of surgery had grade III-IV facial nerve function.

Facial Nerve↗
PubMed1994

Ossicular chain reconstruction. Capitulum to malleus.

Ossicular chain reconstruction is most commonly performed for an absent or diseased incus. Reestablishing continuity by placing a strut prosthesis between the stapes capitulum and malleus handle minimizes the possibility of extrusion and displacement. Strut prostheses are made of hydroxyapetite, which is a highly biocompatible material that bonds to living bone.

Biocompatible Materials↗
PubMed1993

The role of KTP laser in revision stapedectomy.

In recent years, the safety and efficacy of revision stapedectomy has come under scrutiny. Experienced surgeons report that the results of such surgery are often worse than the results after primary surgery and that the risks of sensorineural hearing loss, tinnitus, and vertigo are increased. With the addition of laser technology to revision stapes surgery, the procedure to open the neomembrane over the oval window and gain access to the inner ear can now be performed safely. This allows positive identification of the oval window and assures placement of the prosthesis through the fenestra rather than on an intermediate segment of scar or bone in the region of the footplate. Our studies have shown the laser to be an important tool that enhances the safety and efficacy of revision stapedectomy.

Audiometry↗
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

Jugular foramen schwannomas: diagnosis and suggestions for surgical management.

Schwannomas arising in the parapharyngeal space are rare lesions; however, those originating in the jugular foramen are even less common. Two cases, each with marked intra- and extracranial extensions, are discussed. Clinical presentation and preoperative evaluation emphasizing computerized tomographic and magnetic resonance imaging will be presented. An aggressive two-stage surgical approach consisting of a retrosigmoid craniectomy combined with infratemporal removal is advocated for those lesions arising within the jugular foramen.

Journal Article↗
PubMed1991

Intraoperative cranial nerve monitoring during posterior skull base surgery.

Intraoperative monitoring of neurophysiologic function is rapidly evolving as an important adjunct during skull base surgery to reduce the incidence of neurologic deficit. Facial nerve monitoring is an excellent model, since electrical and mechanical evoked potentials can be directly presented to the surgeon in real-time through an acoustic loudspeaker display. The lower cranial nerves may also be monitored using similar electromyographic techniques. Auditory system monitoring is more difficult due to the low amplitude response that requires averaging and filtering to extract the evoked potential. In conjunction with auditory monitoring, improved hearing preservation may be further enhanced by concomitant facial nerve monitoring, since the surgeon is alerted to traumatic manipulations that may affect both facial and cochlear nerves. Techniques and interpretative issues are presented to maximize the efficacy and safety of cranial nerve monitoring.

Journal Article↗
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↗