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Biomedical subjects

T Lau

Publications and source records attributed to T Lau.

48 records · Page 3Linked to original sources
PubMed1981

[Primary bilateral malignant melanoma of the choroid (author's transl)].

Report on an extremely rare case of primary bilateral malignant melanoma of the choroid with histological verification of both tumors. The patient was a 54-year-old woman; the presumptive clinical diagnosis was a primary bilateral melanoblastoma. A thorough general examination did not reveal any metastases. Six months later the patient underwent surgery. The left eye, in which the tumor was larger, was enucleated and a B-type malignant melanoma of the choroid with invasion of the sclera was diagnosed histologically. Two months later the patient died of a lung embolism. Histological verification of the tumor of the right eye led to the same diagnosis as in the left eye, but without invasion of neighbouring structures. No distant metastases were found at autopsy. A thin layer of slender spindle nevus cells was found between the tumor and the sclera during the histological study. The author agrees with Yanoff and Zimmerman (1967) that this may be regarded as the origin of the malignant tumor.

Choroid Neoplasms↗
PubMedDate not supplied

Long-term results of surgery for chronic granulating otitis.

The late results of planned one-stage procedures in 229 ears with chronic granulating otitis were analyzed, and the justification for two-stage procedures is discussed. All ears were discharging despite intensive preoperative treatment, and all had severe mucosal pathology. The total re-perforation rate was 12%. Five per cent were closed at re-operation, so that at the last follow-up perforations were found in 7% of the ears. The average observation period was 11 years (range, three to 20 years). After one operation, 91% of the ears were dry, and after the re-operations, 98% of the ears were dry. The re-operation rate was 16%. Because of these results obtained by planned one-stage procedures, the authors do not recommend two-stage procedures in non-cholesteatomatous conditions. The authors furthermore conclude that canal-up mastoidectomy is preferable in non-cholesteatomatous granulating otitis.

Adolescent↗
PubMedDate not supplied

Cholesteatoma in children: recurrence related to observation period.

From 1965 to 1978, 122 children with cholesteatoma had one-stage surgery. Follow-up examinations were carried out several times, with the last two taking place in 1980/81 and 1985/86. Ninety-eight percent of the children were seen at follow-up; the median observation time was 11 years, with a range of three to 21 years. The increase in recurrence rate with increasing observation time was analyzed. In 1980/81 there was a total recurrence rate of 12 percent of patients, including residual cholesteatoma in the tympanic cavity in 8%, in the attic in 2%, and recurrent cholesteatoma in 2%. In 1985/86 the recurrence rate had increased to 17%, distributed among residual cholesteatoma in the tympanic cavity in 10.6%, in the attic in 1.6%, and recurrent cholesteatoma in 4.8%. The recurrence rate was the same regardless of whether modified canal-wall-up mastoidectomy or canal-wall-down mastoidectomy had been employed. We conclude that cholesteatoma surgery should be individualized according to pathologic findings in the tympanic cavity, tubal function, and size of the mastoid air cell system. Small cholesteatomas confined to the tympanic cavity may be removed by tympanoplasty alone, without mastoidectomy. In ears with adhesive otitis, canal-wall-down mastoidectomy is preferred; and in ears with a reasonably good tubal function and a large air cell system, canal-wall-up mastoidectomy is recommended. The long-term results reported here seem to indicate that, in children, canal-wall-up mastoidectomy is preferable to canal-wall-down mastoidectomy.

Adolescent↗
PubMedDate not supplied

Sensorineural hearing loss following chronic ear surgery.

The incidence and characteristics of postoperative sensorineural hearing loss were analyzed in 2,303 cases of chronic otitis and its sequelae, representing our total series from 1965 to 1980. Sensorineural hearing loss occurred in a total of 1.2% of cases: 0.5% became totally deaf, and 0.7% acquired a high tone loss, most often at 4 kHz only. The incidence was highest in congenital malformations, granulating otitis and cholesteatoma, mastoidectomy (especially canal-down), and during the period from 1965 to 1974. The most common causes of anacusis were removal of cholesteatoma from the semicircular canal and removal of the fistula membrane. Different types of severe high tone loss are described and, in addition, 19 patients with mild high tone loss are discussed.

Audiometry↗
PubMedDate not supplied

Sagittal plane rotation of the pelvis during lumbar posteroanterior loading.

OBJECTIVE: To determine the extent of sagittal plane rotation of the pelvis during lumbar spine posteroanterior loading. DESIGN: Quantitative study. SETTING: Biomechanics Laboratory, Faculty of Health Sciences, University of Sydney. PARTICIPANTS: Ten male and female subjects with no recent history of significant low back pain. INTERVENTION: A mechanical device was used to apply forces to the L3 spinous process. Data were collected during slow cyclical loading. MAIN OUTCOME MEASURE: The stiffness of the posteroanterior movement at the point of loading was measured, together with the sagittal plane rotation of the pelvis and the resistance to rotation provided by the bed on which the subject lay. RESULTS: Mean pelvic rotation was 2.1 degrees per 100 N applied force (SD 1.01 degrees/100 N). Mean posteroanterior stiffness was 13.4 N/mm (SD 3.13 N/mm) and resistance to pelvic rotation was 2.71 Nm/degree of pelvic rotation (SD 0.84 Nm/degree). CONCLUSION: During posteroanterior force application there is pelvic rotation of a magnitude that may be sufficient to have clinical significance. Abnormalities found during lumbar posteroanterior force application may originate in tissues caudad to the lumbar spine itself.

Adult↗