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Biomedical subjects

I W Nelson

Publications and source records attributed to I W Nelson.

At least 19 recordsLinked to original sources
PubMed2003

Cervical spondyloptosis caused by an aneurysmal bone cyst: a case report.

STUDY DESIGN: The case of an 11-year-old patient with an aneurysmal bone cyst at C7, cervical spondyloptosis, and scoliosis of the lumbar spine is reported. OBJECTIVE: To describe an unusual presentation of aneurysmal bone cyst causing painless cervical spondyloptosis. SUMMARY OF BACKGROUND DATA: Aneurysmal bone cysts of the cervical spine are rare. There has never been a reported case of cervical dislocation by an aneurysmal bone cyst. This case highlights the potentially devastating effects that can be caused by benign tumors in the vertebral column. METHODS: The history, clinical examination, imaging findings, and treatment are reviewed. RESULTS: The patient was treated with a single-stage combined posteroanteroposterior operation to resect the tumor, reduce the cervicothoracic dislocation, and create a three-column stabilization of the spine. The results were satisfactory, with an improvement in neurology. CONCLUSIONS: Aneurysmal bone cysts should be considered in the etiology of complicated scoliosis. Patients with a benign clinical history should be investigated at an early stage using appropriate imaging. Surgery is the treatment of choice when stability of the spine is compromised and neurologic signs are present.

Bone Cysts, Aneurysmal↗
PubMed2000

Mechanical initiation of intervertebral disc degeneration.

STUDY DESIGN: Mechanical testing of cadaveric lumbar motion segments. OBJECTIVES: To test the hypothesis that minor damage to a vertebral body can lead to progressive disruption of the adjacent intervertebral disc. SUMMARY OF BACKGROUND DATA: Disc degeneration involves gross structural disruption as well as cell-mediated changes in matrix composition, but there is little evidence concerning which comes first. Comparatively minor damage to a vertebral body is known to decompress the adjacent discs, and this may adversely affect both structure and cell function in the disc. METHODS: In this study, 38 cadaveric lumbar motion segments (mean age, 51 years) were subjected to complex mechanical loading to simulate typical activities in vivo while the distribution of compressive stress in the disc matrix was measured using a pressure transducer mounted in a needle 1.3 mm in diameter. "Stress profiles" were repeated after a controlled compressive overload injury had reduced motion segment height by approximately 1%. Moderate repetitive loading, appropriate for the simulation of light manual labor, then was applied to the damaged specimens for approximately 4 hours, and stress profilometry was repeated a third time. Discs then were sectioned and photographed. RESULTS: Endplate damage reduced pressure in the adjacent nucleus pulposus by 25% +/- 27% and generated peaks of compressive stress in the anulus, usually posteriorly to the nucleus. Discs 50 to 70 years of age were affected the most. Repetitive loading further decompressed the nucleus and intensified stress concentrations in the anulus, especially in simulated lordotic postures. Sagittal plane sections of 15 of the discs showed an inwardly collapsing anulus in 9 discs, extreme outward bulging of the anulus in 11 discs, and complete radial fissures in 2 discs, 1 of which allowed posterior migration of nucleus pulposus. Comparisons with the results from tissue culture experiments indicated that the observed changes in matrix compressive stress would inhibit disc cell metabolism throughout the disc, and could lead to progressive deterioration of the matrix. CONCLUSIONS: Minor damage to a vertebral body endplate leads to progressive structural changes in the adjacent intervertebral discs.

Adult↗
PubMed2000

Can exercise therapy improve the outcome of microdiscectomy?

STUDY DESIGN: A prospective randomized controlled trial of exercise therapy in patients who underwent microdiscectomy for prolapsed lumbar intervertebral disc. Results of a pilot study are presented. OBJECTIVE: To determine the effects of a postoperative exercise program on pain, disability, psychological status, and spinal function. SUMMARY OF BACKGROUND DATA: Microdiscectomy is often used successfully to treat prolapsed lumbar intervertebral disc. However, some patients do not have a good outcome and many continue to have low back pain. The reasons for this are unclear but impairment of back muscle function due to months of inactivity before surgery may be a contributing factor. A postoperative exercise program may improve outcome in such patients. METHODS: Twenty patients who underwent lumbar microdiscectomy were randomized into EXERCISE and CONTROL groups. After surgery, all patients received normal postoperative care that included advice from a physiotherapist about exercise and a return to normal activities. Six weeks after surgery, patients in the EXERCISE group undertook a 4-week exercise program that concentrated on improving strength and endurance of the back and abdominal muscles and mobility of the spine and hips. Assessments of spinal function were performed in all patients during the week before surgery and at 6, 10, 26, and 52 weeks after. The assessment included measures of posture, hip and lumbar mobility, back muscle endurance capacity and electromyographic measures of back muscle fatigue. On each occasion, patients completed questionnaires inquiring about pain, disability and psychological status. RESULTS: Surgery improved pain, disability, back muscle endurance capacity and hip and lumbar mobility in both groups of patients. After the exercise program, the EXERCISE group showed further improvements in these measures and also in electromyographic measures of back muscle fatigability. All these improvements were maintained 12 months after surgery. The only further improvement showed by the CONTROL group between 6 and 52 weeks was an increase in back muscle endurance capacity. CONCLUSION: A 4-week postoperative exercise program can improve pain, disability, and spinal function inpatients who undergo microdiscectomy. [Key words: electromyogram median frequency, exercise therapy, intervertebral disc prolapse, microdiscectomy, randomized controlled trial, spinal function.

Adolescent↗
PubMed1997

Interactive image-guided surgery of the spine--use of the ISG/Elekta Viewing Wand to aid intraoperative localization of a sacral osteoblastoma.

The intraoperative localization of small osteoid osteomas and osteoblastomas of the spine is often difficult. The authors report a patient with a small sacral osteoblastoma in whom the experimental use of an Interactive Image-Guidance Stereotactic system, to aid localization, is described. The Elekta Viewing Wand is a spatial localization device primarily designed for intracranial procedures. We evaluated its potential role in the localization and minimally invasive excision of a sacral osteoblastoma in this patient. A basic assessment of the limitations encountered in extracranial use of this system is presented and possible solutions to minimize these problems are discussed.

Adult↗
PubMed1995

New prognostic factors to predict the final outcome of brace treatment in adolescent idiopathic scoliosis.

STUDY DESIGN: Eighty-five patients with adolescent idiopathic scoliosis treated with Milwaukee or thoracolumbosacral orthoses at The Duchess of Kent Children's Hospital were studied longitudinally at 4-6-month intervals until maturity for spinal curvature and vertebral rotation, or until termination of brace treatment for persons who experienced brace failure who went on to have surgery. OBJECTIVES: To identify radiologic features so that it may be possible to predict outcome of brace treatment early on. SUMMARY OF BACKGROUND DATA: The structural curve with poor flexibility and large rotational prominence have been found to be associated with poor prognosis for brace treatment. However, early response to bracing for spinal deformity and its relationship to final outcome of brace treatment in a longitudinal study is not available in the literature. METHODS: Vertebral rotation and Cobb angles measured from anteroposterior radiographs of the spine obtained before bracing and 1-2 months after bracing were found valuable for prediction. Changes in post-brace Cobb angle and vertebral rotation were considered as an increase or reduction only when there was an increase or reduction of minimum 5 degrees or more from their prebrace measurements. RESULTS: Those patients who showed increase in vertebral rotation and/or in Cobb angle after brace application were shown to have progression of curves leading to brace failure in 93% of patients, and 79% of these required surgery. The patients with no change in both vertebral rotation and Cobb angle after bracing often experienced brace failure (69%). Two patients (15%) required surgery. The results show that reduction of both Cobb angle and vertebral rotation after application of a brace is a prognostic indicator for a good outcome (97%), and no patients required surgery. Most of the patients with lumbar scoliosis (91%) showed such reductions. CONCLUSION: The findings show a strong association between changes in vertebral rotation and the Cobb angle after application of a brace and the final outcome. Reduction in both is indicative of a good outcome, whereas increase in one or both indicates brace failure.

Adolescent↗
PubMed1992

Total hip arthroplasty for hemophilic arthropathy.

From 1969 until 1985, 39 total hip arthroplasties (THAs) were performed in 38 patients for hemophilic arthropathy. The median age of patients at operation was 48.1 years. Twenty-two of these hip replacements in 21 patients were reviewed clinically and roentgenographically with a median follow-up study of 7.6 years. Five of the 22 hips have been revised and three are likely to require revision in the near future. The incidence of revision is compared to other studies of THA in young patients and the influence of human immunodeficiency virus infection is examined. Total hip arthroplasty in the hemophiliac is believed to be an appropriate operation for disabling hemophilic arthropathy.

Adolescent↗
PubMed1991

Peripheral nerve lesions in hemophilia.

Between 1962 and 1986, eighty-one of the 1351 admissions of patients who had hemophilia to the Nuffield Orthopaedic Centre were for peripheral nerve lesions. Eighty-eight such lesions were identified in fifty-four patients, and thirty-nine of these patients (sixty-one lesions) had adequate follow-up (mean, 8.4 years; range, four months to eighteen years). The femoral nerve was most commonly involved, but involvement of other peripheral nerves also occurred. In thirty (49 per cent) of the sixty-one lesions, the nerve had full motor and sensory recovery; in twenty-one (34 per cent), a residual sensory deficit; and in ten (16 per cent), both a persistent motor and sensory deficit. Patients who had antibodies to factor VIII were significantly less likely to recover full motor or sensory function than were those who did not have such antibodies, and the time to full motor recovery in these patients was significantly longer.

Adolescent↗
PubMed1989

Technical considerations of the AO interlocking nail.

We report 23 patients treated with 24 AO femoral intramedullary locked nails performed at the John Radcliffe Hospital, Oxford. There were no major complications and all 17 acute traumatic fractures followed up for longer than 4 months proceeded to an uncomplicated union, with an excellent range of knee movement.

Bone Nails↗
PubMed1989

A review of fatal road accidents in Oxfordshire over a 2-year period.

The records of 131 road accident fatalities which occurred in Oxfordshire over a 2-year period were reviewed. Aspects of the accident circumstances, the injuries incurred and the cause of death were examined. The majority of fatal accidents occurred during daylight hours and in dry weather. Deaths were mainly due to cerebral injury (34.4 per cent) or uncontrollable (mainly thoracic) haemorrhage (25.2 per cent), or a combination of both (8.4 per cent). A number of deaths occurred in hospital from complications rather than from the injury itself. In addition to this, there were four deaths from natural causes. Where death occurred at the scene of the accident, blood alcohol levels were determined. Almost 50 per cent of the drivers for whom a level was obtained had measurable alcohol in their bloodstream, and 28 per cent of such drivers were over the legal limit. Three cases who reached hospital alive were, on review, assessed to have potentially survivable injuries, and a further two patients died in the post-accident period of potentially survivable complications.

Accidents, Traffic↗
PubMed1986

Craniocervical instability treated by contoured loop fixation.

Rigid posterior fixation of the skull to the third, fourth and fifth cervical vertebrae was achieved in three patients who, as a result of operation, had gross instability of the craniocervical junction. An anatomically contoured steel loop was secured to the occiput via small burr holes and to the vertebrae by sublaminar wiring. This technique has the advantage over bone grafting, either alone or with cement, in that it affords rigid stabilisation, allows early mobilisation and may contribute to eventual bony fusion.

Adult↗