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Biomedical subjects

H O Williams

Publications and source records attributed to H O Williams.

At least 19 recordsLinked to original sources
PubMed1994

Does lithotripsy cause hearing loss?

OBJECTIVE: To determine whether lithotripsy with the Dornier MPL9000 has any significant effect on the hearing of either patients or operators, as determined by pure tone audiometry. PATIENTS AND METHODS: Twenty patients had audiometry prior to a single exposure to lithotripsy and one hour after treatment. Staff were monitored on a 3 monthly basis. RESULTS: No evidence was found to suggest that single or repeated exposure to the noise emitted by this Dornier lithotripter was associated with any hearing loss. CONCLUSIONS: These results suggest that the risk to the hearing of patients exposed to lithotripter noise is negligible. Cochlear damage resulting from excessive noise depends on both the intensity of the sound and the duration of exposure. The acoustic properties of the building housing the machine may also be important and can significantly influence the intensity of the sound at the ear. At marginal levels it may be years before the deficit reaches a level that can be detected by subjective audiometry. In addition, susceptibility to noise induced hearing loss is difficult to predict. Although these results suggest that there is minimal risk to the hearing of staff members exposed to lithotripter noise, the authors recommend that staff exposed to repeated lithotripter noise over long periods undergo regular audiometric assessment (including a preemployment baseline assessment) to identify evidence of noise induced auditory trauma, and that protective equipment be worn by staff members to reduce the possibility of long-term damage.

Audiometry↗
PubMed1992

Nasal teeth.

Ectopic and supernumerary teeth occur in a wide variety of sites. Those that have been reported include the mandibular condyle, coronoid process, orbit, palate, nasal cavity and the maxillary antrum. Eruption of teeth into these sites is rare, and easily overlooked. We present two cases in which eruption of teeth into the nose and paranasal sinuses was associated with significant morbidity and show how this was relieved by appropriate surgery.

Adult↗
PubMed1992

Necrobacillosis--an unusual cause of cervical abscess.

Necrobacillosis is a rare infection which may be fatal if inadequately treated. We present a case demonstrating the classical clinical picture upon which correct diagnosis depends. The need for a high index of suspicion is highlighted and appropriate management is discussed.

Abscess↗
PubMed1991

Radiological study of primary spontaneous CSF rhinorrhoea.

A radiological study of skull base anatomy was performed in patients presenting with primary spontaneous CSF rhinorrhoea. Radiology correctly identified the fistula site in 90 per cent of cases. Contrast CT imaging was found to be the most suitable technique for identifying the presence and site of CSF fistulae. However, pre-contrast bony dehiscences were identified in all patients leaking from the cribriform plate region. More significantly, all of these patients showed deviation of their crista galli, a radiological sign hitherto unreported. These findings support the theory that congenital bony dehiscence is the aetiological basis for this condition. The importance of radiology in the management of this condition is emphasized.

Bone Diseases↗
PubMed1991

Tegmental dehiscence and brain herniation into the middle ear cleft.

The tegmen tympani may occasionally be breached by herniation of the temporal lobe with or without dural cover. The clinical presentation may be obvious with CSF otorrhoea but less so with apparent middle ear effusion, CSF rhinnorrhoea, conductive hearing loss, recurrent meningitis or intracranial sepsis. Diagnosis requires suspicion of the condition, which may be aided by radiological imaging. Surgical repair is to be recommended: various techniques are available but bone enveloped by fascia placed by subtemporal approach is preferred. The features of this problem are highlighted by four cases.

Adult↗
PubMed1988

An evaluation of topical anaesthesia for myringotomy.

The relative efficiency of 2 topical anaesthetic agents in controlling the pain arising from myringotomy and grommet insertion has been assessed by a prospective, single blind controlled trial. The 2 anaesthetics were 5% cocaine and a new lignocaine and prilocaine mixture named Emla. Following a standardized anaesthetic procedure the pain arising from myringotomy, aspiration of the middle ear and subsequent insertion of a grommet was recorded by the patient on a linear analogue scale. A multivariate analysis was performed to assess the factors which significantly affected the pain levels. Only the type of anaesthetic used played a major role, with Emla giving significantly better anaesthesia than cocaine.

Adolescent↗
PubMed1987

Morbidity and mortality of common bile duct exploration.

This retrospective study reviews the complications which occurred in 257 patients who had supraduodenal exploration of the common bile duct in one hospital during a 15-year period. One hundred and eighteen patients (46 per cent) developed complications: septic and cardiorespiratory complications were most common, occurring in 19.5 per cent and 16.7 per cent of patients respectively. Postoperative retained stones were detected in 37 patients (14 per cent), causing complications in 54 per cent. Peroperative postexploratory cholangiography did not significantly reduce the incidence of this problem. None of the 12 patients who had postexploratory choledochoscopy had retained stones. Five patients (1.9 per cent) died, three of whom had duct procedures in addition to supraduodenal exploration and two of whom had retained stones. It is concluded that common bile duct exploration has a high associated morbidity, particularly due to sepsis and retained stones.

Adult↗
PubMed1987

Modified enzyme immunoassays for tobramycin using reduced sample and reagent volumes.

The accuracy of two modified enzyme immunoassay (EMIT) methods using reduced sample and reagent volumes for determining serum tobramycin concentrations was compared with that of the standard method. The modified EMIT assays used sample and reagent volumes of 25 and 30 microL instead of the standard 50-microL volumes. Solutions of tobramycin sulfate with known concentrations of 1, 2, 4, 8, and 12 mg/L were assayed five times using each of the three methods. Fourteen blood samples containing unknown concentrations of tobramycin were obtained from patients over a four-week period and assayed once by each method. The mean percentage recovery of tobramycin using the standard 50-microL sample-volume method (104.4 +/- 8.8%) was not significantly different from that of the 30-microL (106.6 +/- 9.9%) or the 25-microL (100.4 +/- 11.4%) assay method. There was good correlation between the standard method and the 25-microL (r = 0.993) and the 30-microL (r = 0.988) methods for determining unknown tobramycin concentrations. If the 25- and 30-microL assays were used in place of the standard 50-microL assay, costs would be reduced and the number of assays per kit would increase. The 30-microL and 25-microL sample and reagent volumes used in this study for the tobramycin EMIT assay allow substantial cost savings without a significant loss in accuracy.

Analysis of Variance↗
PubMed1985

Comparison of venous and capillary blood sampling for the clinical determination of tobramycin serum concentrations.

Tobramycin concentrations have been determined in serum from capillary, venous and arterial blood samples taken from 16 patients during and after surgery. In 73 paired samples the concentrations in capillary samples were not significantly different from those measured in venous samples. The small concentration differences were neither dependent upon sampling time nor core-peripheral temperature differences. In 26 paired samples, concentrations in capillary samples were not significantly different from those determined in arterial samples. We conclude that concentrations in capillary samples are precise and unbiased estimators of venous concentrations and may be used in the adjustment of tobramycin dosage regimens.

Adult↗