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Biomedical subjects

Zoran Becvarovski

Publications and source records attributed to Zoran Becvarovski.

7 recordsLinked to original sources
PubMed2004

Positional vomiting due to a thoracic spinal dural arteriovenous fistula. Case report.

The authors report the unique case of a patient with a thoracic spinal dural arteriovenous fistula (DAVF) causing remote brainstem symptoms of positional vomiting and minimal vertigo. Magnetic resonance (MR) imaging of the brain demonstrated high signal abnormality in the medulla, presumably related to venous hypertension, and spinal MR imaging revealed markedly dilated veins along the dorsal aspect of the cord. Spinal angiography confirmed the presence of a thoracic spinal DAVF. Disconnection of the DAVF from the spine resulted in a marked improvement in symptoms and resolution of the preoperative MR imaging-documented abnormalities. The authors highlight the rare syndrome of positional vomiting as a brainstem symptom and conclude that spinal DAVFs should be considered in the differential diagnosis of high signal MR imaging abnormalities localized to the brainstem.

Angiography↗
PubMed2002

Intratympanic ciprofloxacin and the human labyrinthine sampling model.

OBJECTIVE: The aim of the study was to investigate the potential absorption of intratympanic ciprofloxacin through the human round window membrane. STUDY DESIGN: A prospective study. METHODS: Ciprofloxacin was instilled into the middle ear of 10 patients undergoing acoustic tumor removal. The lateral semicircular canal and vestibule were subsequently opened and, using a microsyringe, labyrinthine fluid was aspirated. A sample each of serum and cerebrospinal fluid was also drawn. RESULTS: Into each middle ear, 0.5 mL ciprofloxacin (0.3%) was instilled. The time interval between the ciprofloxacin application to the round window membrane and sampling of labyrinthine fluid and plasma ranged from 9 to 120 minutes. There was no measurable ciprofloxacin in the labyrinthine fluid, cerebrospinal fluid, or serum of 10 patients. CONCLUSION: The lack of measurable absorption of intratympanic ciprofloxacin into the inner ear indicates that the chance of ototoxicity when ciprofloxacin is used clinically, even in the presence of a tympanic membrane perforation, is low.

Aged↗
PubMed2002

Over-under tympanoplasty.

OBJECTIVE: Common techniques of tympanic membrane repair include underlay and overlay grafting. The over-under tympanoplasty, an innovative method for tympanic membrane repair, will be described as a reliable alternative that has advantages over traditional procedures. STUDY DESIGN: This study was a retrospective case review. SETTING: Tertiary referral center with hospital-setting surgery and outpatient ambulatory patient visits. PATIENTS: One hundred twenty patients who underwent over-under tympanoplasty were included in this study. Average follow-up was 1.8 years. INTERVENTION: Over-under tympanoplasty is performed by placing the graft over the malleus and under the annulus. This technique was used for patients undergoing ear surgery for chronic otitis media, perforations, cholesteatoma, and/or conductive hearing loss. All degrees of ear pathology were included. MAIN OUTCOME MEASURES: Main outcome measures were graft success (no perforation, atelectasis, or lateralization within 6 mo) and improvement of hearing. Patients were stratified by severity of disease (according to the Middle Ear Risk Index), cholesteatoma presence, and type of mastoidectomy. RESULTS: All 120 patients had successful grafts. Lateralization of the grafted drum did not occur. Seventeen patients had late atelectasis, and 12 patients had late perforations; nearly all of these were noted more than 1 year after surgery and were attributed to persistent eustachian tube dysfunction or infections. Average improvement in air-bone gap for all patients was 5.3 dB, whereas speech reception threshold improved by 5.9 dB. CONCLUSION: Over-under tympanoplasty has an excellent success rate while being technically easier than lateral tympanoplasty. Thus, it is a useful method for practitioners of all levels.

Adolescent↗
PubMed2002

Rapid elevation of gentamicin levels in the human labyrinth following intravenous administration.

HYPOTHESIS: Adequate quantities of labyrinthine fluid can be sampled from the human labyrinth to perform quantitative analysis of medications. A rapid elevation of intralabyrinthine gentamicin levels after intravenous administration can be measured. A model for the sampling of human inner ear fluid in this manner is described. BACKGROUND: The risk of aminoglycoside ototoxicity has been a long-standing concern. The kinetics of gentamicin diffusion into the inner ear have been extrapolated to humans from various animal models. The validity of extrapolation to humans is unknown. We have developed a new model to measure the uptake of gentamicin in vivo. METHODS: A single intravenous dose of gentamicin (80 mg) was given perioperatively to 13 patients undergoing translabyrinthine acoustic neuroma surgery. The lateral semicircular canal and vestibule were opened and a microsyringe was used to obtain a sample of labyrinthine fluid concomitant with a serum sample. The gentamicin concentration of the labyrinthine fluid and serum was analyzed using a standard chemistry analyzer. RESULTS: After parenteral administration of gentamicin, fluid was obtained from the inner ear of 13 acoustic neuroma patients. Inner ear concentrations were between 1.0 and 3.8 mg/L. Serum gentamicin levels ranged from 1.2 to 10.5 mg/L. CONCLUSIONS: This method allows the sampling of intralabyrinthine fluid in humans. Gentamicin was noted immediately in the labyrinth after intravenous administration. This model may be expanded to measure other compounds given either by intravenous or transtympanic routes.

Adult↗
PubMed2002

Round window gentamicin absorption: an in vivo human model.

OBJECTIVE/HYPOTHESIS: Using a novel human labyrinthine sampling model, in vivo gentamicin absorption through the round window can be measured. STUDY DESIGN: A prospective study. METHODS: Gentamicin was delivered either transtympanically (preoperative) or through a facial recess approach (intraoperative). The lateral semicircular canal and vestibule were opened, and by means of a microsyringe, labyrinthine fluid was aspirated. A sample of serum was also drawn. In all patients cerebrospinal fluid was also drawn. The samples were analyzed using a standard chemistry analyzer. RESULTS: Intratympanic gentamicin diffused through the round window membrane and achieved concentrations in the labyrinthine fluid ranging from 0 to 16 mg/L. Intratympanic gentamicin was absorbed into the systemic circulation in 4 of 11 patients with serum levels ranging from 0.3 to 0.4 mg/L. No gentamicin was detected in the cerebrospinal fluid. CONCLUSIONS: Intratympanic gentamicin diffuses rapidly through the round window membrane and achieves significant levels in the inner ear. Thus, this new model can be used to assess round window permeability to clinically relevant medications such as steroids and ototopical antibiotics.

Adult↗