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Biomedical subjects

P A Bird

Publications and source records attributed to P A Bird.

11 recordsLinked to original sources
PubMed2001

Prospective evaluation of magnetic resonance imaging and physical examination findings in patients with greater trochanteric pain syndrome.

OBJECTIVE: This study examined patients with greater trochanteric pain syndrome (GTPS) to determine the prevalence of gluteus medius pathology by utilizing magnetic resonance imaging (MRI), and to evaluate the presence of Trendelenburg's sign, pain on resisted hip abduction, and pain on resisted hip internal rotation as predictors of a gluteus medius tear in this group of patients. METHODS: Twenty-four subjects with clinical features consistent with GTPS were recruited. A standard physical assessment was performed at study entry, including assessment of the 3 specific physical signs. Following this initial assessment, MRI of the affected hip was performed. A 1.5T whole body MRI system was utilized, with T1 and T2 fast spin-echo sequences performed in the coronal and axial planes. All MR images were reviewed in random order by a single radiologist. In 12 patients, the 3 physical signs were assessed at study entry and at 2 months by the same observer and the intraobserver reliability for each of the signs was calculated. RESULTS: All subjects were women (median age 58 years, range 36-75 years). The median duration of symptoms was 12 months (range 12-60 months). MRI findings were as follows: 11 patients (45.8%) had a gluteus medius tear, 15 patients (62.5%) had gluteus medius tendinitis (pure tendinitis in 9 patients and tendinitis with a tear in 6 patients), 2 patients had trochanteric bursal distension, and 1 patient had avascular necrosis of the femoral head. Trendelenburg's sign was the most accurate of the 3 physical signs in predicting a tendon tear, with a sensitivity of 72.7% and a specificity of 76.9%. Moreover, Trendelenburg's sign was the most reliable measure, with a calculated intraobserver kappa of 0.676 (95% confidence interval 0.270-1.08). CONCLUSION: The results support the hypothesis that gluteus medius tendon pathology is important in defining GTPS. In this series, trochanteric bursal distension was uncommon and did not occur in the absence of gluteus medius pathology. The physical findings suggest that Trendelenburg's sign is the most sensitive and specific physical sign for the detection of gluteus medius tears, with an acceptable intraobserver reliability. Further delineation with MRI, especially in patients with a positive Trendelenburg's sign, is recommended prior to any consideration of surgery in this group of patients. Finally, with the pathology of this condition defined, the challenge will be to devise and assess, by randomized controlled trial, an appropriate treatment strategy for this group of patients.

Adult↗
PubMed2001

Questioning the sensitivity of magnetic resonance imaging in early septic spondylodiscitis.

Septic spondylodiscitis is an uncommon disease, but one with serious complications and potentially high morbidity and mortality. The diagnosis is sometimes delayed, particularly in those patients with an insidious mode of onset and nonspecific symptoms. Several imaging methods are available to facilitate the early diagnosis of septic spondylodiscitis, and of these methods magnetic resonance imaging (MRI) has been reported to be the most sensitive, revealing abnormalities earlier than plain x-ray, gallium scan and bone scan. We report a case of septic spondylodiscitis in which MRI did not demonstrate evidence of discitis after a symptom period of seven days. The diagnosis was later confirmed by bone scan and repeat MRI. We suggest that a negative or equivocal MRI cannot exclude infective spondylodiscitis, especially in the early stages of the disease process. In such cases, it is important to note that the addition of a short tau-inversion recovery sequence will increase the sensitivity of MRI, and, additionally, gadolinium should be administered if the magnetic resonance study is negative and a strong clinical suspicion of spondylodiscitis exists.

Journal Article↗
PubMed1999

Cochlear reimplantation.

OBJECTIVE: A small number of multichannel cochlear implant (CI) recipients require reimplantation. This study describes the causes of failure, surgical technique, and hearing outcomes in a consecutive series of 16 patients undergoing reimplantation of multichannel devices. We hypothesize that reimplantation is safe and that hearing results are at least as good as those measured following primary implantation. STUDY DESIGN: Retrospective analysis of consecutive clinical series. METHODS: Chart analysis of 191 consecutive CI operations performed at the University of Miami Ear Institute between 1990 and 1997 revealed 16 patients who received a second multichannel device. All but one had a minimum follow-up of 1 year after reimplantation. Ten of these patients had initial implantation performed by us, and six were initially operated on elsewhere. Main outcomes of the initial procedure were compared with those of the reimplantation, including electrode insertion length, number of channels programmed, and audiometric results. In addition, cause of failure and relevant surgical findings at the second procedure are described. RESULTS: There were no surgical complications after reimplantation surgery. Device failure was the most frequent cause for reimplantation. Time between initial implantation and failure ranged from 0 to 46 months (mean, 22.4 mo; median, 23 mo). Common intraoperative findings include mastoid fibrosis, bone growth at the cochleostomy, and skin flap breakdown. Following reimplantation, mean length of insertion, number of channels actively programmed, and speech recognition scores were at least as good as findings before initial implant failure. CONCLUSION: CI reimplantation is safe and effective.

Adolescent↗
PubMed1999

Using the CLARION cochlear implant in cochlear ossification.

This paper is a retrospective review of 5 patients with various degrees of cochlear ossification who were implanted with the CLARION Multi-Strategy Cochlear Implant. Preoperative computed tomography scans, intraoperative findings, surgical technique, and hearing outcomes are discussed in a case report format. Full implantation was achieved in all cases by a systematic approach that included drill-through of proximal obstruction (2 cases), scala vestibuli insertion (2 cases), and complete drill-out (1 case). The only complication was delayed wound healing in a patient with sickle cell disease, chronic active hepatitis, and steroid dependency on antimetabolite therapy. Early results show that the 4 patients with at least 3 months of experience have a mean open-set sentence recognition score of 55% and a mean open-set word recognition score of 24%. The conclusion is that implantation of the Clarion device in ossified cochleas can be successful in all degrees of ossification and can provide significant hearing benefit.

Adolescent↗
PubMed1999

Hearing results with deep insertion of cochlear implant electrodes.

OBJECTIVE: This study aimed to investigate the relationship of electrode insertion length and speech recognition in patients using Nucleus-22 cochlear implants. STUDY DESIGN: The study design was a retrospective review of a consecutive clinical series. SETTING: The study was conducted at an academic medical center. PATIENTS: Thirty-one postlingually deafened adults with at least 6 months' experience with a Nucleus-22 cochlear implant using Spectra-22 processor and SPEAK strategy participated. MAIN OUTCOME MEASURES: Open-set speech recognition scores for words and sentences were measured. RESULTS: Insertion length ranged from 22 rings (estimated 17 mm) to 32 rings (estimated 25 mm). Mean word recognition score was 35%. Mean sentence score was 69.6%. Statistical analysis showed no correlation between insertion depth and word or sentence scores. CONCLUSION: Insertion of the Nucleus-22 array beyond 22 rings does not improve performance in speech recognition. This finding cannot be generalized to other electrodes or processing strategies.

Adult↗
PubMed1998

Surgical technique for implantation of the totally ossified cochlea.

OBJECTIVES: Among the technical challenges of cochlear implant surgery is electrode insertion into the fully ossified cochlea. Earlier drill-out techniques have two significant drawbacks: 1. up to one half fail when the electrode pulls away from the cochlea; and 2. extended radical mastoidectomy, abdominal fat graft for obliteration, and closure of the external auditory meatus are required. A simplified technique is described that allows positive fixation of the cochlear implant electrode and in selected cases avoids a radical cavity with obliteration. STUDY DESIGN: Technical description with case reports and hearing outcomes. METHODS: Ten cadaver temporal bones were dissected to determine middle ear landmarks that overlie the basal turn of the cochlea from the transcanal approach and to establish the feasibility of the intact canal wall procedure. Surgery was performed on four patients who had preoperative imaging evidence of full ossification, two with the canal wall down, and two with canal wall up. Standard measures of speech recognition were used to evaluate hearing. RESULTS: Critical surgical landmarks are the round window, carotid artery, cochleariform process, and oval window. The procedure was successfully performed on four patients and open-set speech recognition is present in each. CONCLUSIONS: This canal wall up procedure allows long electrode insertion without radical cavity/obliteration in patients with fully ossified cochleas and prevents distraction of the electrode from the cochlea. While open-set word recognition was achieved by all subjects, results are poorer than expected for patients with limited or no ossification.

Audiometry, Speech↗
PubMed1978

Haemodialysis-induced leucopenia and activation of complement: effects of different membranes.

The effects on neutrophil count and complement activity of five different haemodialysis membranes were studied. There was no correlation between the degree of neutropenia and intensity of complement activation. With cuprophan membrane both occurred simultaneously but to unrelated degrees; polyacronitrile induced mild, not significant neutropenia but marked activation of complement; polycarbonate membranes induced severe neutropenia without detectable complement activation. Where complement activation occurred it was via the alternative pathway. Haemodialysis induced neutropenia may have many causes and complement activation is probably not the major responsible factor.

Acrylic Resins↗