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Biomedical subjects

L G Duckert

Publications and source records attributed to L G Duckert.

At least 37 records · Page 2Linked to original sources
PubMed1987

Single-point stabilization of zygomatic fractures with the minicompression plate.

Unstable zygomatic fractures frequently require stabilization at two points. A new "mini" dynamic compression plating system designed specifically for zygomatic fractures permits single-point stabilization. We used a minicompression plating system with a series of patients at the University of Washington Affiliated Hospitals, Seattle. Satisfactory single-point stabilization of displaced zygomatic fractures was consistently achieved with this method. The plate and screws are substantially smaller than commonly used in mandibular fractures facilitating cosmetic concealment. There are theoretical advantages of this plating system as they apply to the unique geometry of the zygomatic fracture.

Bone Plates↗
PubMed1986

Reversible mechlorethamine-associated hearing loss in a patient with Hodgkin's disease.

Mechlorethamine, when administered in massive doses (0.6-1.5 mg/kg) to cancer patients in several early studies, caused severe irreversible hearing loss. There have been no reports of ototoxicity with doses of 0.4 mg/kg or less. The authors describe a 36-year-old man who developed profound sensorineural hearing loss during his first cycle of MOPP chemotherapy for Hodgkin's disease. Cyclophosphamide was substituted for mechlorethamine in subsequent cycles and his hearing deficit resolved. This is the first reported case of reversible ototoxicity associated with currently recommended doses of mechlorethamine.

Adult↗
PubMed1986

Preliminary observations after facial rehabilitation with the ansa hypoglossi pedicle transfer.

Facial paralysis is a very disabling condition, both functionally and cosmetically. Despite the different methods of facial reanimation that have been described, there is no single method that will restore normal facial tone and motion. Of the methods available, primary neurorrhaphy is probably the most effective. The recovery period, however, is prolonged and, as a result, muscle tone and bulk may be lost. The hypoglossal-facial anastomosis is also a very reliable and effective technique but requires necessary interruption of both major cranial nerve trunks. Transfer of a neuromuscular pedicle (based on the ansa hypoglossi) has been offered as a method of facial reanimation that involves neither prolonged recovery nor interruption of the major cranial nerve functions. The application of this technique for reinnervation of a paralyzed larynx was first described by Tucker in 1970, and the technique was applied to facial muscle (in animal models) in 1977. The effectiveness of this technique--and its application in the management of facial paralysis in the human patient--remains controversial. We report our experience with a series of six patients who underwent neuromuscular pedicle transfer in conjunction with other more conventional methods of facial reanimation. The function of the pedicle and its contribution to the overall facial rehabilitation were assessed clinically and electromyographically. Factors influencing the success of the procedure and clinical and experimental evidence to support its application are discussed. While our experience with this technique is limited, it would appear that the neuromuscular pedicle transfer may play a useful adjunctive role in reanimation of the face in selective cases of facial paralysis.

Adult↗
PubMed1985

Morphologic changes in the guinea pig cochlea following cochleostomy--a preliminary scanning electron microscope study.

Fistulization of the membranous labyrinth via a surgically created endolymphatic-perilymphatic shunt (cochleosacculotomy) is currently being advocated as a treatment for endolymphatic hydrops. As a preliminary study to the investigation of the effects of labyrinthine fistulization on the hydropic condition, we sought first to reproduce the cochleosacculotomy procedure in a series of normal animals. Fistulization of the cochlear duct was performed in 15 normal animals using a tungsten wire directed via the round window through the cochlear partition in the region of the organ of Corti. The animals were sacrificed at regular intervals and the cochleas examined for histopathologic changes with the scanning electron microscope. Observations suggest that discrete permanent fistulization of the cochlear duct in the normal guinea pig results in progressive sensory cell degeneration. The implication of these observations and the apparent difference between these results and the experience thus far reported in humans are discussed.

Animals↗
PubMed1984

Placebo effect in tinnitus management.

Masking devices, lidocaine, and analog oral forms of lidocaine have all been reported as being effective forms of therapy to relieve tinnitus. Many studies, however, have used single-blind protocols and were possibly biased by placebo effects. To investigate the contributions of a placebo effect in clinical tinnitus studies, 25 tinnitus patients who had received a placebo injection in a previous double-blind lidocaine study were contacted on the pretense that they would receive a test dose of lidocaine; the 20 who responded were included in this study. A 5 cc bolus of placebo saline solution instead of lidocaine was then administered to each patient. Forty percent of the patients reported a change in their tinnitus following the placebo injection. The results of this study serve to point out the inherent flaws in straight clinical trials, and that the success rates achieved in such uncontrolled clinical investigations may be biased by the placebo effects.

Clinical Trials as Topic↗
PubMed1984

Morphological changes following cochlear implantation in the animal model.

Examination of the effects of cochlear implantation in the animal model has made it increasingly clear that biological changes may be induced by the device. In a preliminary study we established a damage threshold at 400 microA RMA (70 microCoul/cm2/phi) after a single three-hour exposure to continuous 1 kHz sinusoidal stimulation. By systematic modification of stimulation parameters in the present study we have sought to establish damage thresholds and patterns of histological change in the chronically stimulated animal and further elucidate the mechanisms underlying the histopathological change in a second acute animal preparation. In part one, chronic stimulation at 1 000 Hz for a total of 12 hours distributed over a four-week period resulted in a lower damage threshold at 15-20 microCoul/cm2/phi, the lowest value tested. In addition to sensory and supporting cell degeneration osteoneogenesis and spiral ganglion cell degeneration were also observed. These findings are of some relevance under conditions of prolonged implantation and stimulation in the human. In part two of the study, acute stimulation for a three-hour period at 100 Hz reduced the damage threshold from 400 microA to 200 microA RMS. This inverse relationship between threshold and frequency suggests that electrophoretic effects are, at least in part, responsible for the histological changes observed. The threshold shift was less than predicted, however, making it less likely that a single factor is responsible for the stimulation-induced damage.

Acoustic Stimulation↗
PubMed1983

Aspiration cytology: an efficient and cost-effective modality.

Aspiration cytology is under-utilized in the evaluation of neck masses. This paper establishes the historical perspectives for the procedure which document its accuracy and safety. The discussion emphasizes the appropriate application of the technique and the strong arguments for its cost effective use as a primary diagnostic modality in evaluation of head and neck mass lesions.

Aged↗
PubMed1983

Comparison of geometric and "real" surface areas of cochlear electrodes.

The destructive potential of the electrically active electrode is believed to be related to charge density at the electrode-tissue surface. Charge density has been calculated with the use of both geometric and electrochemical "real" values for surface area. To further assess the accuracy of surface area measurements determined by means of the previously mentioned methods, an eight-electrode modiolar array cochlear implant was examined. Electrode surface areas were measured first electrochemically, then by means of a light microscope, and finally with the use of the scanning electron microscope. Comparison of these measurements demonstrated a high correlation between the scanning and light microscopic values. However, there was no correlation between the surface areas determined by light and scanning electron microscopy and the electrochemical measurements.

Cochlear Implants↗
PubMed1983

Treatment of tinnitus with intravenous lidocaine: a double-blind randomized trial.

Several recent reports have suggested that intravenous (IV) lidocaine is an effective form of therapy to relieve tinnitus; however, many of these studies were not well controlled. A double-blind randomized trial to assess the effectiveness of IV lidocaine on tinnitus was conducted at the University of Washington-affiliated hospitals on a total of 50 patients. Tinnitus was evaluated before and after injection by subjective assessment and audiometric matching. Although 40% of the lidocaine group reported a decrease in tinnitus, over 30% of the lidocaine group reported increased tinnitus after administration of the drug. There was also a high incidence of side effects, including disequilibrium, slurred speech, numbness, and tingling of the extremities in the drug group. The results of the study suggest that the clinical usefulness of IV lidocaine in relieving tinnitus may be less than was previously reported.

Adult↗
PubMed1983

Morphological changes in the normal and neomycin-perfused guinea pig cochlea following chronic prosthetic implantation.

The effects of chronic prosthetic implantation and interval electrical stimulation were studied in the normal and neomycin-perfused cochlea of the guinea pig. One group of guinea pigs was implanted with a multiple-electrode prosthesis in the scala tympani. During a 4-week period, the device was stimulated for 3 hours weekly with a continuous, 1 kHz sinusoidal current of constant intensity. A second group of guinea pigs underwent identical implantation and stimulation except that cochlear perfusion with .1 M neomycin was performed at the time of implantation. Current intensities ranged from .1 to .6 mA RMS. Two complementary control groups were implanted but not stimulated. The animals were sacrificed, the cochleae were perfused with a fixative, and the temporal bones were prepared for examination under a light, transmission, or scanning electron microscope. In the electrically stimulated cochleae, degenerative changes occurred in both the inner and outer hair cells and supporting elements. A decrease was apparent in spiral ganglion cell and nerve fiber populations in areas of inner hair cell depletion and did not seem to correspond to the survival of supporting cells. The electrically active electrodes were uniformly surrounded by a connective tissue matrix and areas of immature bone. These changes occurred at all the intensities tested, and did not monotonically relate in severity to current intensity. None of the changes was apparent in the normal control ears. Morphological changes induced by the ototoxic drug neomycin were so severe is both stimulated and unstimulated cochleae that comparison was not possible; this form of pretreatment is apparently unsuitable for use in studies of electrically induced damage. It appears that in the normal animal, chronic implantation with interval electrical stimulation results in a cumulative form of sensory and neural damage histologically similar to that proceeding from chronic noise exposure as well as other ototoxic agents. Such effects should be minimized if surviving sensorineural and supporting elements in the functionally compromised cochlea are to be preserved.

Animals↗
PubMed1981

Phenytoin-induced lymphadenopathy appearing as a nasopharyngeal malignant neoplasm.

A case of phenytoin sodium-induced lymphadenopathy appeared as a nasopharyngeal malignant neoplasm with regional metastases. Cervical lymphadenopathy is a lesser-known drug reaction that is produced by anticonvulsant therapy; under some circumstances, this condition may be confused with head and neck malignant neoplasms. To date, phenytoin-induced nasopharyngeal lymphadenopathy has not previously been reported in the literature. A review of the medical literature provides some interesting facts about the syndrome. A familiarity with this potential complication of anticonvulsant therapy may expedite early diagnosis and appropriate patient treatment.

Adult↗
PubMed1978

Computerized axial-tomography in the preoperative evaluation of an angiofibroma.

Computerized axial tomography (CAT) of the head provides the otolaryngologist with an effective diagnostic tool. This technique is particularly useful when used in the preoperative evaluation of head and neck pathology and may be used to define the extent of disease and to direct the surgical approach. The case of a 16-year-old male with an extensive angiofibroma involving the paranasal sinuses and nasopharynx is presented as an example of CAT in preoperative planning of the surgical procedure. Computerized tomography was used initially to define the tumor margins. Serial CAT scans were also obtained at intervals during the patient's preoperative estrogen therapy. Evidence was obtained which suggests CAT may be used to monitor the effects of preoperative hormone management of angiofibromas and in the definition of the optimal time for surgery. In the case presented the final CAT scan provided a detailed and accurate description of the tumor margins which were confirmed at surgery. Our experience with a case of an extensive nasopharyngeal angiofibroma demonstrates the CAT scan to be a useful objective diagnostic method for preoperative planning.

Adolescent↗
PubMed1977

Stabilization of comminuted zygomatic fractures with external suspension apparatus.

An external fixation device using a suspension bar fashioned from dental compounds is described. The finished appliance resembles a drawer pull from which the fractured malar eminence is suspended. The apparatus is recommended for the treatment of comminuted, unstable zygomatic fractures where conventional means of stabilization have proved unsatisfactory or undesirable and where passive traction is desirable. Appliances fashioned from lightweight dental compounds offer the maxillofacial surgeon a safe, effective, and highly versatile means of stabilizing facial fractures.

Acrylic Resins↗
PubMed1977

Diagnosis in persistent cerebrospinal fluid fistulas.

Cerebrospinal fluid (CSF) rhinorrhea and otorrhea have presented difficult problems in both diagnosis and management; moreover, the threat of impending meningitis necessitates early localization of the source of the leak. The most common techniques for evaluation and isolation of CSF rhinorrhea and otorrhea have included X-ray studies, intrathecal dyes, and radioactive cisternography...

Adolescent↗