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Biomedical subjects

V M Williams

Publications and source records attributed to V M Williams.

9 recordsLinked to original sources
PubMed1998

Outcome analysis of noninstrumented anterior cervical discectomy and interbody fusion in 348 patients.

STUDY DESIGN: Twenty-one outcome and outcome-relevant variables (fusion and patient satisfaction) were evaluated in a subset of 348 of 514 patients operated on by one surgeon during a 22-year period, using Cloward's anterior cervical discectomy and dowel interbody fusion. Minimum patient follow-up was 2 years; average length of follow-up was 5.2 years. This retrospective analysis is accompanied by a comprehensive review of the literature (1975-1996) of noninstrumented anterior cervical fusions, excluding fibular grafts alone in the interbody space. OBJECTIVES: To provide data on outcome (with regard to patient satisfaction and radiologically supported fusion) and risks of noninstrumented anterior cervical discectomy and fusion for intractable cervical nerve root and spinal cord compression symptoms at single or multiple levels, using the results from a single surgeon. METHODS: Three experienced spine radiologists determined fusion rates in one to five levels in 348 patients on the basis of the results of plain film analysis. Patient self-assessment was used to determine degree of patient satisfaction and other related variables. From a comprehensive review of the literature, 43 clinical reports meeting requirements for comparison of findings with those in the current study were selected from more than 1600 reports. RESULTS: The mean fusion rate for 348 patients in the current study ranged from 75% (multilevel) to 88% (one level; n = 202). The overall fusion rate was 83%. The persistent complication rate was 0.1%, and patient self-assessments showed that 78% were satisfied with the outcome and that 83% returned to work. The overall fusion rate for 2037 patients evaluated in the comprehensive literature review is 92%. CONCLUSIONS: Results of this study indicate that better outcome in noninstrumented anterior cervical discectomy and fusion is associated with solid fusion, fewer fused levels, nonsmoking patients, higher education levels, and absence of secondary economic gain. There was no correlation between fusion status and bone graft source or use of cervical collar.

Adult↗
PubMed1996

Laparoscopic knot security.

The security of several types of laparoscopic and open knots and varying suture materials was tested in an attempt to improve suture and knot selection for advanced laparoscopic procedures. Six different types of knots and five suture materials were tested. All sutures were of 2-0 size, and laparoscopic knots were tied using a pelvic trainer. A typical number of square throws was used for each suture. Stress was gradually applied by withdrawing the ends of a manual digital tensiometer until either the knot slipped or the suture parted. The maximum stress withstood by the knot-suture complex was recorded, as was whether the knot was secure (i.e., whether the knot held until the suture broke). The data were analyzed using analysis of variance to compare the knot security of the various knot types and the different sutures using a given knot. No significant difference was found in security or stress resistance between laparoscopic square and open square knots or in the Dacron, polypropylene, and expand polytetrafluoroethylene (ePTFE) extracorporeal and intracorporeal knots, with the exception of ePTFE intracorporeal knots, which were significantly less secure (p = 0.028). Silk suture was significantly less secure than all the other sutures tested for all knots tested (p < 0.0001). The Roeder's and Fisherman's knots were the least secure of all laparoscopic knots in all sutures tested (p < 0.0001), with the exception of polyglactin tied with a fisherman's knot, which was as secure as the extracorporeal and intracorporeal polyglactin knots. These experiments showed laparoscopic square knots to be as secure as open square knots; removing the operating finger from the knot does not seem to affect the security of a well-tied square knot. Furthermore, of the permanent sutures tested, there was no substantive difference in the security of laparoscopic intracorporeally and extracorporeally tied knots, except that ePTFE was more secure when tied with extracorporeal throws. Our data also suggest that silk is not as secure as other permanent suture materials.

Humans↗
PubMed1990

Management of isolated thyroid swellings: a prospective six year study of fine needle aspiration cytology in diagnosis.

OBJECTIVE: To audit the accuracy and impact on the frequency of operation of fine needle aspiration cytology of isolated thyroid swellings. DESIGN: Prospective analysis over six years of cytological predictions compared with histological findings. SETTING: Thyroid clinic serving the Grampian region. PATIENTS: 395 Consecutive patients presenting with an isolated thyroid swelling, 307 of whom underwent surgical excision. Analysis was confined to a subgroup of 283 patients with satisfactory aspirates who were operated on. RESULTS: The positive predictive value of aspiration cytology for detecting malignant disease was 100% and the sensitivity 83%. The sensitivity for the detection of neoplasia (frank malignancy together with follicular adenomas) was 76%. The specificity was 58% and the overall accuracy 69%. Recalculation of data in previous papers with strict criteria showed the accuracy of aspiration cytology to be variable and lower than is widely accepted. Since the introduction of aspiration cytology 21% fewer operations for isolated thyroid swellings have been performed. CONCLUSIONS: As a basis of selection for surgical excision of isolated thyroid swellings according to prediction of neoplasia fine needle aspiration cytology is less reliable than is widely accepted. It is an adjunct to management rather than a definitive test, and negative cytological results do not exclude neoplastic disease. Further study should take account of the implications of repeated clinic attendances for review and aspiration as these may culminate in delayed surgical treatment.

Biopsy, Needle↗
PubMed1986

Donovanosis in Western Australia.

We report and discuss a series of 47 consecutive patients with donovanosis that were diagnosed in a public health laboratory in Western Australia during slightly more than six years. Most came from the tropical northern parts of Western Australia, there was a preponderance of women in the series, and vulval lesions were the most common manifestation of the disease. Two men had extragenital lesions, though each was eventually found to have concomitant genital lesions.

Adult↗
PubMed1985

Fine needle aspiration cytology in isolated thyroid swellings: a prospective two year evaluation.

During 1 September 1981 to August 1982 aspiration cytology was carried out in all isolated thyroid swellings referred to the Aberdeen Thyroid Clinic: cytological findings were not disclosed, did not influence management, and were compared retrospectively with the histological diagnosis. In a total of 70 swellings sensitivity for the detection of neoplasia was 86% and overall accuracy 92%; the positive predictive value was 80% and negative predictive value 96%. During the second year (1 September 1982 to 31 August 1983), when cytological findings were used to influence management, the frequency of operation for isolated thyroid swellings decreased by 25% and the proportion of operations for neoplasia increased from 31% to 50%. In terms of bed occupancy the potentially avoidable surgical workload for benign disease was reduced by 34%. Aspiration cytology, carried out at the first clinic attendance, makes a sound basis for selective surgery and leads to economy in the management of isolated thyroid swellings.

Adult↗
PubMed1985

Crown repair with a cast post and core.

A technique to make a post and core pattern that can be used to save an existing crown has been presented. The technique should become an additional tool in the treatment armamentarium.

Crowns↗
PubMed1977

Bis-(4-methylumbelliferyl) phosphate as a substrate for the surface membrane-associated phosphodiesterase activity of pig platelets.

It was found that the newly-available compound, bis-(4-methylumbelliferyl) phosphate, could be used as a substrate for the pig platelet surface membrane-associated phosphodiesterase activity, usually assayed with bis-(p-nitrophenyl) phosphate. This enzyme activity is distinct from the phosphodiesterase activity towards 5'-dTMP-P-nitrophenyl ester, which is probably associated with intracellular membrane structures in platelets. Consequently, the use of the 4-methylumbelliferyl derivative as substrate for the phosphodiesterase activity provides a sensitive, fluorimetric assay for this marker enzyme of the platelet surface membrane.

Animals↗