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Biomedical subjects

R S Walker

Publications and source records attributed to R S Walker.

At least 19 recordsLinked to original sources
PubMed2003

Glomus tumor as a cause of chronic low back pain: case report.

STUDY DESIGN: A case of chronic low back pain caused by a glomus tumor that persisted more than 30 years is presented. OBJECTIVE: To emphasize the need to consider skin tumors in the differential diagnosis of low back pain. SUMMARY OF BACKGROUND DATA: Chronic low back pain can be caused by a myriad of factors. There are six relatively common skin tumors, which present as painful lesions. As seen in the reported case, if they occur in the lumbar region, they can cause low back pain. METHODS: A subject with low back pain underwent an excision biopsy of a localized area of tenderness where his symptoms were reproduced when light pressure was applied. RESULTS: Histology confirmed that a glomus tumor accounted for the subject's pain. CONCLUSIONS: Painful skin tumors may cause low back pain and need to be considered in the differential diagnosis of chronic low back pain.

Chronic Disease↗
PubMed1999

Comparative corneal topography and refractive variables in monozygotic and dizygotic twins.

PURPOSE: To investigate the role of heredity in determining corneal shape, axial length, and overall refractive error. METHODS: Twenty monozygotic and 19 dizygotic twin pairs, age 12 to 73 years, were enrolled in the study. Zygosity was determined by physical similarity and by responses to questions adapted from surveys. Two twin pairs were excluded because of undetermined zygosity and one pair because of keratoconus (both siblings). Refractive error was determined by an automated refractor. Manifest refraction was also recorded, as well as cycloplegic refraction in subjects under age 18 years. Corneal topography data and manual keratometer readings were also obtained. Axial lengths were determined by A-scan ultrasound. Data were analyzed by Student t tests only in the right eye. Left-eye data were comparable for all variables. RESULTS: Mean intrapair difference in refractive error (spherical equivalent) was less for monozygotic than for dizygotic twins (RE: 0.41 vs 1.53; P = .001). Mean intrapair difference in axial length was less for monozygotic twins (RE: 0.39 vs 0.76 mm; P = .031). Corneal topography data (power and meridian) in all zones (3, 5, and 7 mm) also showed smaller mean differences among monozygotic pairs than dizygotic, but the difference was statistically significant only for the 5-mm zone. In addition, most Holladay Diagnostic Summary variables that were studied did not show any statistically significant differences. CONCLUSIONS: Axial length and overall refractive error have a significant genetic basis. Corneal topography data appear to have other overriding determining factors for several of the variables studied.

Adolescent↗
PubMed1997

Submacular surgery for subfoveal choroidal neovascular membranes in patients with presumed ocular histoplasmosis.

OBJECTIVE: To determine the visual results, recurrence rates, and postoperative complications of surgical removal of subfoveal choroidal neovascularization (CNV) in patients with the presumed ocular histoplasmosis syndrome. DESIGN: A consecutive surgical series of 63 eyes of 62 patients with subfoveal CNV and the presumed ocular histoplasmosis syndrome with longer than 6 months of follow-up. SETTING: Tertiary care university medical center. METHODS: Patients underwent surgical removal of subfoveal CNV using vitreoretinal surgical techniques. The anatomical and functional results of surgery were analyzed. RESULTS: The median age of the patients was 42 years (range, 16-68 years), and the median follow-up time was 24 months (range, 6-48 months). Visual acuity improved by 2 or more Snellen lines in 22 (35%) of the 63 eyes, was unchanged in 28 (44%) of the eyes, and worsened in 13 (21%) of the eyes. Eleven (17%) of the 63 eyes improved to a visual acuity of 20/50 or better. Eyes with an initial visual acuity of 20/200 or worse had a better prognosis for improved vision (ie, 26 [41%] of the eyes) than those with an initial visual acuity of 20/100 or better (ie, 5 [8%] of the eyes). Recurrence of the subfoveal CNV occurred in 24 (38%) of the 63 eyes and was more common in those eyes that received preoperative laser photocoagulation (ie, 15 [47%] of the eyes). The median time to recurrence was 5 months after surgery. Post-operative complications included macular striae in 4 (6%) of the 63 eyes, rhegmatogenous retinal detachment in 2 (3%) of the eyes, retinal tear in 1 (1.6%) of the eyes, and progression of cataract in 19 (30%) of the eyes. CONCLUSIONS: Surgical excision of subfoveal CNV may be an effective therapeutic modality in patients with the presumed ocular histoplasmosis syndrome that offers the possibility of improving central vision in many patients. Factors possibly associated with a favorable visual prognosis include younger patient age and the absence of previous laser photocoagulation.

Adolescent↗
PubMed1997

Therapeutic ERCP: a cost-prohibitive procedure?

BACKGROUND: ERCP is increasingly being performed for therapeutic purposes and engenders a proliferation of disposable equipment without a clear indication of cost-effectiveness. METHODS: We analyzed the financial impact of ERCP by prospectively analyzing ERCPs performed in our institution from June 1, 1994, to September 30, 1994, by calculating charges related to indirect costs, disposable equipment costs, and overall reimbursement. The data were analyzed according to insurance payor as well. RESULTS: Disposable equipment costs a mean of $149 per diagnostic ERCP and $532 per therapeutic ERCP. For diagnostic ERCP, disposable equipment accounted for 27% of reimbursement; for therapeutic ERCP, disposable equipment accounted for 68% of reimbursement. Although overall reimbursement was higher for therapeutic ERCP, the very high direct costs related to disposable equipment limited the ability of reimbursement to cover indirect costs. CONCLUSIONS: Depending on the complexity of cases, quantity of disposable equipment used, and patient-insurance mix, therapeutic ERCP may be cost prohibitive for a given endoscopy unit. Indirect costs should be more carefully and quantitatively analyzed. Disposable equipment should be evaluated in terms of cost, safety, and patient outcome.

Cholangiopancreatography, Endoscopic Retrograde↗
PubMed1994

Surgical excision of periorbital capillary hemangiomas.

BACKGROUND: Periorbital capillary hemangiomas of childhood can produce ptosis, strabismus, and anisometropia, resulting in amblyopia. Traditional therapy with either systemic or local corticosteroids occasionally yields incomplete resolution of these lesions and may be associated with numerous adverse complications. The authors report their experience performing surgical resection of periorbital capillary hemangiomas. METHODS: Twelve children with periorbital capillary hemangiomas were treated surgically. Six of these children had previously failed to adequately respond to steroid injections and six were primarily treated with surgical resection. All lesions were believed to be localized and did not appear to be infiltrative on preoperative computed tomographic scans. RESULTS: All lesions were completely resected, except for two in which there was a small area of residual hemangioma surrounding the lacrimal drainage system that was left intact. Controlled intraoperative hemorrhage in two patients required intraoperative directed-donor blood transfusion. Perioperatively, in one patient a wound dehiscence developed, which required minor repair. This same patient elected to have surgical scar revision postoperatively. The patients have been followed up to 5 years. All did well with improved cosmesis, and they have good lid function. No recurrences have been noted. CONCLUSION: Surgical resection of pediatric capillary hemangiomas should be considered a treatment option in those that fail to respond to corticosteroids and/or are isolated and noninfiltrative in nature.

Betamethasone↗
PubMed1989

Microscopic examination of embrittled pin-retained base metal casting.

Differential thermal analysis, optical microscopy, scanning electron microscopy, and energy dispersive radiographic analysis were used to examine and analyze two failed platinum-palladium-gold pin-retained nickel-chromium castings. The microstructure and chemical composition of the pin-casting interface were different from those of the pin and the cast alloy. Porosity was also observed at the interface. The observations with these samples suggest that the pin melted during casting. The embrittlement and failure of plantium-palladium-gold pins cast with nickel-chromium alloy have been attributed to this melting phenomenon. Further study is necessary to determine whether these observations are valid for a large number of samples.

Chemical Phenomena↗
PubMed1979

Homoeopathic medicine.

Explore the source record for details and available documents.

Attitude of Health Personnel↗
PubMed1977

Centralised interpretation of electrocardiograms.

A system was devised so that a peripheral hospital could transmit electrocardiograms (ECGs) to a central computer for interpretation. The link that transmits both ECGs and reports is provided by the telephone network. Initial results showed that telephone transmission did not significantly affect the accuracy of the ECG interpretation. The centralised computer programme could be much more widely used to provide ECG interpretations. A telephone link would not be justified in health centres, where the demand for ECGs is fairly small, but ECGs recorded at a health centre can be sent to the computer for interpretation and returned the next day. The most cost-effective method of providing computer interpretation for several health centres in a large city would be to have a portable electrocardiograph and transmission facilities, which could be moved from centre to centre.

Diagnosis, Computer-Assisted↗