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Biomedical subjects

R Eliashar

Publications and source records attributed to R Eliashar.

At least 19 recordsLinked to original sources
PubMed2001

Dynamic tissue expansion of the larynx in a canine model.

OBJECTIVES: To test whether staged, progressive, monitored, dynamic tissue expansion is possible in the larynx and to evaluate its effectiveness in dilating and augmenting constricting cicatricial lesions. DESIGN: Animal study. SETTING: Research facility, tertiary care medical center. SUBJECTS: Thirteen dogs, 3 with laryngotracheal stenosis. INTERVENTIONS: Dogs underwent laryngeal splits, tracheostomy, and insertion of inflatable stents. In 7 normal dogs, stents were progressively inflated by air in predetermined increments during 11 days. In 3 normal dogs and 3 with laryngotracheal stenosis, stents were gradually expanded by water. Stents were kept in place for 21 days. After removal, dogs were observed for 25 days. Five died of complications of tracheostomy. MAIN OUTCOME MEASURES: Airway diameter measured by endoscopy before the induction of stenosis, before the laryngeal splitting procedure, after stent removal, and before euthanasia. RESULTS: The lumen increased, then shrank somewhat after stent removal. In 2 surviving dogs with laryngotracheal stenosis and water-expanded stents, the lumen was 82.5% larger than baseline at stent removal and 71.0% larger at euthanasia. In 2 surviving normal dogs with water-expanded stents, lumen size increased by 50.0% at stent removal, and in 1 dog surviving to day 46, it was 17.0% larger. In 5 surviving dogs with air-inflated stents, lumen size was 39.0% larger at stent removal and 8.0% larger at day 46. Histologically, fibrous tissue developed in the gaps between the splayed margins of the laryngeal cartilages. CONCLUSIONS: The larynx may be dynamically expanded. Although the maximal diameter is not maintained, final cross-sectional areas are larger.

Animals↗
PubMed2000

Improved canine model for laryngotracheal stenosis.

Laryngotracheal stenosis (LTS) is a serious challenge for the otolaryngologist. Although progress has been made in preventing and treating LTS, more research is required. Existing canine models for LTS incur high mortality and morbidity, require relatively complicated procedures or costly equipment, entail lengthy waiting periods, or have unpredictable results. A simple, reliable, and inexpensive procedure, requiring no tracheotomy, is described for creating a canine model for LTS research. The new improved model is compared with previous models described in the literature. It will be especially useful for short-term studies of subglottic or tracheal stenosis.

Animals↗
PubMed2000

Assessment of vestibular ototoxicity of ear drops by recording of vestibular evoked potentials to acceleration impulses.

INTRODUCTION: The cochlear ototoxicity of several ear drops is well documented in the literature, but very few studies exist on the vestibular ototoxicity of these topical drugs. GOAL OF STUDY: To develop an animal model for the assessment of the vestibular ototoxicity of ear drops. MATERIALS AND METHODS: Two animal groups, consisting of five fat sand rats (FSRs) each, underwent unilateral labyrinthectomy. Normal saline was topically applied into the middle ear cavity of rats in the first group for 7 days (control group). Rats in the second group were treated in the same way by topical gentamicin solution. Cochlear function was assessed by the recording of auditory evoked potential (ABPs) thresholds, and vestibular function was assessed by the recording of vestibular evoked potentials (VsEPs) to angular accelerations. RESULTS: In the control group, except for the amplitude of the first wave, there was no significant difference in the VsEPs recorded before and after topical application. In the gentamicin group, VsEPs could not be recorded after 7 days, and ABPs were recorded in one case only, with a threshold of 100 dB sound pressure level (SPL). CONCLUSION: VsEPs seem to be a reliable measure for evaluating the vestibular ototoxicity of topical ear drops.

Administration, Topical↗
PubMed2000

Effect of mechanical reinforcement on stability of the rotary door flap laryngotracheal reconstruction: a canine study.

OBJECTIVE/HYPOTHESIS: The rotary door flap (RDF) laryngotracheal reconstructive procedure uses a 180 degrees rotation of the sternohyoid muscle into a laryngofissure. Despite excellent clinical results, there are concerns of flap inspiratory prolapse. This study examined RDF stability and the efficacy of ancillary materials in providing additional support. METHODS: Seventeen dogs underwent endoscopic induction of subglottic stenosis and delayed RDF reconstruction. Animals received 1) traditional RDF (control), 2) RDF with titanium screen implant, 3) RDF with porous polyethylene implant, or 4) RDF with hydroxyapatite cement (HAC) injection. Four weeks postoperatively the flaps were tested for stability. On qualitative assessment, endoscopic visualization was completed with quiet respiration and then following endotracheal tube occlusion. On quantitative assessment, after animals were killed, the RDF segment was isolated and subjected to negative pressure (maximum pressure, -50 mm Hg). The pressure-causing collapse was measured. RESULTS: In the traditional RDF animals (control), five of six flaps were stable in vivo and with negative pressures. In the titanium screen, porous polyethylene group, and HAC groups, respectively, four of four, three of four, and two of three flaps were stable in vivo and under negative pressure. Flaps that demonstrated instability had granulation, dehiscence, and poor healing. These occurred in 1 of 6 animals in the traditional RDF group and in 2 of 11 animals in the implant groups. In addition, 13 of 24 animals assigned to the implant groups died, compared with 2 of 8 of those in the traditional RDF group. CONCLUSIONS: The RDF is stable and maintains the airway under physiological conditions. Support materials did not improve stability, render flap harvest more difficult, or increase morbidity and mortality.

Animals↗
PubMed2000

Artifactual thickening of the sinus walls on computed tomography: a phantom model and clinical study.

Measuring sinus wall thickness on computed tomography may be important for distinguishing between acute and chronic inflammation of the paranasal sinuses or in cases of a suspected neoplasm. The objective of this study was to investigate the effects of opacified and aerated sinuses on the appearance of sinus wall thickness. A phantom model consisting of a skull half-immersed in water was scanned, and various slice thicknesses and different windows were used. The sinus walls of the water-immersed side appeared to be thicker than those of the aerated side. Bone windows did not completely eliminate this partial volume effect. It was concluded that comparison between a fluid- or tissue-filled sinus and an air-filled counterpart is not accurate enough for evaluating sinus wall thickness. Bone windows do not completely eliminate the artifactual thickening of the bony wall of a filled sinus.

Adult↗
PubMed2000

Evaluating laryngotracheal stenosis in a canine model with virtual bronchoscopy.

We performed a prospective masked animal study to determine whether virtual bronchoscopy, a noninvasive computed tomography technique, can accurately measure upper airway stenosis. Virtual bronchoscopy creates a 3-dimensional endoscopic image from spiral computed tomography data. Laryngotracheal stenosis was endoscopically induced in 18 dogs. The excised larynges were examined by endoscopy, virtual bronchoscopy, and macrodissection. Measurements were made of the anteroposterior (A-P) diameter, the left-right (L-R) diameter, the full length of stenosis in the sagittal plane, and the length of the tightest stenotic segment. Each measurement method was performed independently. All investigators were unaware of measurements made by others. The measurements obtained through virtual bronchoscopy and actual endoscopy were compared to those made at dissection by interclass correlation coefficients (ICCs). Endoscopy was better than virtual bronchoscopy in measuring the A-P diameter (ICC = .79, p < .0001; ICC = .42, p = .01). Both were equally effective in measuring the L-R diameter (ICC = .53, p = .0062; ICC = .52, p = .0064). The endoscopes could not assess the full length of the stenosis, whereas virtual bronchoscopy measured it fairly accurately (ICC = .72, p = .0001). Virtual bronchoscopy relatively accurately measured the length of the tightest stenotic segment (ICC = .68, p = .0002), whereas endoscopy produced measurements in only 11 of 18 larynges, and the measurements were less accurate (ICC = .45, p = .0068). Virtual bronchoscopy can provide good measurements of stenotic lesions in the airway. It is more accurate than actual endoscopy in determining the length of stenosis. It may therefore be useful as an adjunct imaging method in preoperative planning for reconstructive surgery.

Aged↗
PubMed2000

A case of squamous papilloma after uvulopalatopharyngoplasty.

We report the case of an adult who developed an isolated-solitary papilloma on the margin of the soft palate 1 month after he had undergone a uvulopalatopharyngoplasty. We describe the clinical and cellular characteristics of this common lesion.

Humans↗
PubMed1999

Can topical mitomycin prevent laryngotracheal stenosis?

OBJECTIVES/HYPOTHESIS: Early topical application of mitomycin to a laryngotracheal lesion may prevent or reduce laryngotracheal stenosis (LTS). STUDY DESIGN: Prospective controlled animal study. METHODS: LTS was induced in 60 dogs randomly assigned to four groups. Controls received an immediate topical application of normal saline. The suction-control group received an immediate application of normal saline followed by suction of secretions on day 2. The mitomycin group received immediate application of 0.7 mL mitomycin (0.2 mg/mL). The repeat-mitomycin group received an immediate application of mitomycin and a second application on day 2, after secretions were suctioned. The laryngeal lumens were measured endoscopically at baseline, day 12, and day 21. Animals were euthanatized if stenosis approximated 95% or at day 21. RESULTS: All dogs in the mitomycin groups survived to day 21, compared with 12 in the suction group and only 2 controls. No side effects of mitomycin were observed. At day 21, surviving controls had 85% and 95% stenosis. In the mitomycin group, median stenosis was 27% (interquartile range, 29% to 42%); in the repeat-mitomycin group, 30% (22% to 40%); and in the suction-control group, 84.5% (72.5% to 93.5%). The mitomycin group differed significantly from controls on day 12 (median difference = 85%, 95% CI = 80%-94%, P < .0001) and day 21 (difference = 63.9%, 95% CI = 58%-85%, P = .031). CONCLUSION: A single topical application of mitomycin significantly reduces the severity of LTS in dogs. Reapplication after 2 days does not improve results. Prospective clinical studies are warranted to assess the efficacy in humans.

Administration, Topical↗
PubMed1999

Computed tomography diagnosis of esophageal bone impaction: a prospective study.

A prospective study was performed on 45 patients for an assessment of the use of computed tomography (CT) in the management of a suspected esophageal fish bone or chicken bone. All patients had negative findings on laryngoscopy; therefore, pharyngeal and hypopharyngeal foreign bodies were excluded from further consideration. The patients underwent radiographic examination with plain films and a cervical CT scan without contrast material. Patients with positive findings were taken to the operating room, where they underwent rigid esophagoscopy under general anesthesia, while those with negative findings remained for observation for 24 hours. Thirty CT scans were positive for an esophageal foreign body, and in all cases but 1, a foreign body was found during the operation. Fourteen of 15 patients with normal CT scan findings managed well with no further intervention. One patient with persistent complaints underwent esophagoscopy, but no foreign body was found. Our conclusion is therefore that CT is a simple and reliable method for diagnosing esophageal bone impaction and may reduce the rate of unnecessary esophagoscopies.

Adult↗