Biomedical subjects

Jeffrey T Vrabec

Publications and source records attributed to Jeffrey T Vrabec.

6 recordsLinked to original sources

PubMed2003

Delayed-onset facial paralysis after vestibular neurectomy.

OBJECTIVES/HYPOTHESIS: Delayed-onset facial paralysis (beginning more than 3 d after the procedure) has been described as a complication of many different types of otological procedures. The incidence of this problem in vestibular neurectomy and the relationship to surgical approach are detailed in the study. STUDY DESIGN: Retrospective case review. METHODS: In the setting of a tertiary referral center, vestibular neurectomy was performed in 70 individuals with disabling vertigo unresponsive to medical therapy who elected vestibular neurectomy. The main outcome measure was incidence of delayed onset facial paralysis. RESULTS: Delayed-onset facial paralysis was significantly more common after the middle fossa (18%) and translabyrinthine (11%) approaches compared with the retrosigmoid approach (0%). CONCLUSIONS: Surgical approach influences the incidence of delayed-onset facial paralysis. Measures to prevent this complication such as prophylactic antiviral medication or labyrinthine segment decompression may be considered in middle fossa and translabyrinthine operations.

Adult↗

PubMed2002

Evaluation of the internal auditory canal with virtual endoscopy.

OBJECTIVE: Three-dimensional imaging can improve the understanding and comprehension of complex anatomy. Recent advances in software development allow the construction of a virtual endoscopic view of anatomic structures. This report applies virtual endoscopic capabilities to imaging of the internal auditory canal. STUDY DESIGN, SETTING, AND PATIENTS: We conducted a retrospective case review at a tertiary referral center of patients with abnormal internal auditory canal anatomy on computed tomography. INTERVENTIONS: Computed tomography images were obtained using conventional clinical algorithms involving multiple, 1-mm-thick slices through the temporal bone. Three-dimensional reconstructions were made using General Electric Advantage Windows Navigator software. The virtual endoscopic image-processing algorithm used selected image intensity threshold levels to visualize internal auditory canal anatomy from an endoscopic perspective. RESULTS: Eleven cases of abnormalities of the internal auditory canal were retrospectively identified. Clinical applications using the virtual endoscopic images are presented. The virtual endoscopic images supported prior clinical decision making in 6 of the 11 cases evaluated. CONCLUSION: This technique shows promise for the diagnosis, surgical planning, and teaching of temporal bone anatomy. Usefulness is dependent on acquisition parameters and clinical indications for examination.

Algorithms↗

PubMed2002

3D CT imaging method for measuring temporal bone aeration.

OBJECTIVE: 3D volume reconstruction of CT images can be used to measure temporal bone aeration. This study evaluates the technique with respect to reproducibility and acquisition parameters. MATERIAL AND METHODS: Helical CT images acquired from patients with radiographically normal temporal bones using standard clinical protocols were retrospectively analyzed. 3D image reconstruction was performed to measure the volume of air within the temporal bone. The appropriate threshold values for air were determined from reconstruction of a phantom with a known air volume imaged using the same clinical protocols. The appropriate air threshold values were applied to the clinical material. RESULTS: Air volume was measured according to an acquisition algorithm. The average volume in the temporal bone CT group was 5.56 ml, compared to 5.19 ml in the head CT group (p = 0.59). The correlation coefficient between examiners was > 0.92. There was a wide range of aeration volumes among individual ears (0.76-18.84 ml); however, paired temporal bones differed by an average of just 1.11 ml. CONCLUSIONS: The method of volume measurement from 3D reconstruction reported here is widely available, easy to perform and produces consistent results among examiners. Application of the technique to archival CT data is possible using corrections for air segmentation thresholds according to acquisition parameters.

Adult↗

PubMed2002

Inverting papilloma of the temporal bone.

OBJECTIVES: Inverting papilloma of the temporal bone is exceedingly rare. The objective is to familiarize the clinician with the clinical presentation and prognosis of this entity. STUDY DESIGN: Retrospective case study and literature review. METHODS: Published reports of inverting papillomas originating in the temporal bone were reviewed in conjunction with two cases presenting at the University of Texas Medical Branch (Galveston, TX). RESULTS: Inverting papillomas of the temporal bone are frequently associated with persistent middle ear effusion and ipsilateral sinonasal tumors and display a higher incidence of malignancy. CONCLUSIONS: Successful management of these tumors requires an aggressive surgical resection. Adjuvant radiation therapy is recommended in patients with malignant changes.

Aged↗

PubMed2002

Hydroxyapatite prosthesis extrusion.

OBJECTIVE: To examine the mechanism of prosthesis extrusion and evaluate preoperative and postoperative variables associated with extrusion of hydroxyapatite prostheses for ossicular reconstruction. STUDY DESIGN: Retrospective case review. SETTING: Tertiary referral, university medical center. PATIENTS: Patients undergoing ossiculoplasty with a hydroxyapatite prosthesis and having at least six months follow-up. MAIN OUTCOME MEASURE: Prosthesis extrusion, defined as loss of the tympanic membrane resulting in exposure of the prosthesis. Extrusion is further classified into early (< 2 months) and late (> 6 months). RESULTS: Early extrusion or tympanoplasty graft failure occurred in 15/195 cases (8%). Late extrusion was seen in 17/125 cases (14%). Cases exhibiting late extrusion had a significantly greater incidence of postoperative atelectasis (p < 0.0001), recurrent otitis media (p < 0.0001), and myringitis (p = 0.003) than those with retention of the prosthesis. Regression analysis found an abnormal contralateral ear increased the risk of postoperative recurrent otitis media, while staged surgery reduced the risk, odds ratios of 3.56 (95% confidence interval 2.20-9.37) and 6.84 (95% CI 4.24-17.76) respectively. There were no preoperative variables that predicted postoperative atelectasis or myringitis. CONCLUSIONS: Recurrent otitis media, myringitis, and atelectasis developing after ossiculoplasty are associated with a greater risk of prosthesis extrusion. Predicting postoperative complications from preoperative and intraoperative findings proved difficult. Measures to prevent atelectasis, such as covering the prosthesis with cartilage, are recommended at the time of ossiculoplasty.

Cartilage↗

PubMed2002

Facial nerve grading systems (1985-2002): beyond the House-Brackmann scale.

OBJECTIVE To assess methods of evaluating the function of the facial nerve that have been introduced over the past 15 years, particularly in comparison with the House-Brackmann scale. DATA SOURCES A Medline search was undertaken of the English-language medical literature between 1983 and 2000 to identify proposed methods of evaluating facial nerve function. STUDY SELECTION Although all grading systems were considered, attention was focused on the systems that provided improvements in either precision or ease of use. CONCLUSIONS Because of the limitations and subjectivity of the House-Brackmann scale, several new scales of various degrees of objectivity and ease of use have been introduced. The Nottingham system offers a more objective but easy-to-use facial nerve grading system that has been demonstrated to be valid and that would be easy for the average practitioner to adopt. The authors propose a more systematic evaluation of this system to determine whether its widespread application is appropriate.

Cerebellar Neoplasms↗