Biliary lithotripsy. Determination of stone fragmentation success and potential tissue injury in swine.

Application of extracorporeal shock wave lithotripsy to gallbladder stones was studied in 37 adult female swine. Twenty-two sows underwent cholecystostomy with implantation of human gallstones. In 20 animals, after a 10-day recovery period, extracorporeal shock wave lithotripsy, 2000 shocks (an amount determined in preliminary water bath studies to be effective), was performed. In 10 of these implanted swine, frequent focal point refocusing and biplanar ultrasonography were employed. Two animals served as operative controls. Fifteen other animals without gallstone implantation were studied for adverse effects of extracorporeal shock wave lithotripsy on tissue. These animals (unimplanted) received 5000 shocks; 7 animals were killed 1 to 4 days after treatment and the others were killed after 4 weeks. Biochemical tests (total bilirubin, alkaline phosphatase, lipase, amylase, alanine aminotransferase, and lactate dehydrogenase determinations) were performed on all animals at entry and every second or third day until they were killed. Successful fragmentation, defined as all residual gallstone fragments being less than or equal to 4 mm in greatest dimension, was achieved in 14 of 20 animals overall, but in 10 of 10 animals in which focal point refocusing had been used. Slight perivascular hemorrhage and minimal coagulation necrosis were seen histologically only in the liver parenchyma adjacent to the gallbladder bed. The remainder of the liver was grossly and histologically normal. No injuries to the colon, duodenum, common bile duct, or pancreas were observed. No alterations suggesting injury or altered function occurred in any of the biochemical tests.

DNA content in radiation-associated thyroid cancer.

DNA content has been reported to be of prognostic significance in differentiated thyroid carcinoma. Since malignant tumors with irradiation as an initiator often contain DNA aberrations, the DNA content of well-differentiated thyroid carcinoma in patients with a prior history of low-dose head and neck irradiation was determined and compared with similar nonradiation-associated lesions. The DNA content of thyroid cancers from 53 patients was determined with use of flow cytometry. Sixteen radiation-associated thyroid carcinomas (11 papillary, 3 follicular, and 2 medullary) all were diploid. In a group of 37 nonradiation-associated tumors, 10 were aneuploid (10 of 29 papillary carcinomas and 0 of 2 follicular or 6 medullary carcinomas). This difference in DNA content is significant (p less than 0.02, Fisher's exact test). These findings were unexpected and suggest that if the initiating irradiation causes a DNA aberration, this aberration is not reflected in DNA content as measured by means of flow cytometry.

Sleep deprivation and resident performance.

Cognitive and complex motor performance may be impaired by extended sleep deprivation, but objective data concerning the effects in residents of the sleep deprivation engendered by usual hospital on-call schedules are scant and conflicting. We studied three cohorts of surgical residents (N = 26) who were on call every other night. Each resident kept a sleep diary, gave a self-assessment of motivation and fatigue, and underwent a battery of psychometric tests each morning for 18 or 19 days. The psychometric tests measured cognition, discernment, visual and auditory vigilance, and rapid eye-hand coordination. Sleep deprivation was defined as the lack of four hours of continuous sleep during the preceding 24 hours, and it occurred during 89% of the on-call nights. Daily testing in a repeated-measures design allowed each participant to serve as his or her own control. Sleep deprivation did not affect overall cognitive or motor performance. Further analysis of the correlation between sleep parameters (total sleep and longest uninterrupted sleep interval) and performance on each component of the psychometric test battery identified changes in performance on some tests but only trivial effects due to sleep. The assumption that sleep deprivation associated with usual on-call schedules impairs cognitive and motor performance of residents such that clinical care of patients may be compromised is not supported by our observations.

The effect of parathyroidectomy on the recurrence of nephrolithiasis.

Little information is available on the long-term influence of parathyroidectomy on the rate of renal stone formation in patients with primary hyperparathyroidism (pHPT) and nephrolithiasis. The reported occurrence of renal stone disease in untreated patients with pHPT is 15% to 30%. A registry of 258 pHPT patients who underwent parathyroidectomies at the Milwaukee Regional Medical Center has allowed continued follow-up of the 71 (28%) pHPT patients with associated renal stone disease. Patients have been followed up for an average of 5 years (range, 1 to 15 years) since surgery. The rate of renal stone formation before and after parathyroidectomy was compared. Identification of a "new" renal stone was defined as passage and collection, extraction, or radiographic visualization of stones. All 71 pHPT patients with stone disease had hypercalcemia and inappropriately elevated parathyroid hormone concentrations, and after parathyroidectomy these values returned to normal in 69 of 71 patients. Since undergoing parathyroidectomy, only 4 patients have passed renal stones. The rate of stone formation per patient per year was 0.36 before and 0.02 after surgery (p less than 0.001). Surgical correction of pHPT significantly reduced the rate of stone formation.

Total or near total thyroidectomy versus limited resection for radiation-associated thyroid nodules: a twelve-year follow-up of patients in a thyroid screening program.

Controversy continues regarding the extent of thyroidectomy appropriate for patients with radiation-associated thyroid nodules. The incidence of cancer in this group of patients is more than 50% when near total or total thyroidectomy is done and all thyroid tissue is serially sectioned and examined. Tumor multicentricity is common. Is total or near total thyroidectomy warranted in all of these patients? A prospective study and follow-up program of 2118 patients with prior low-dose head and neck irradiation who entered into a thyroid screening program allowed us to examine how the extent of thyroidectomy influenced the clinical course of these patients. Near total or total thyroidectomy was performed in 59 patients (36 had cancer), and limited thyroid resection, that is, lobectomy or less, was done in 78 patients (four of whom had cancer). During follow-up, only three patients have developed recurrent cancer; two had near total thyroidectomy and one had total thyroidectomy at first operation. Two patients with limited thyroid resection have had reoperation for new thyroid nodules, both of whom had benign nodules. We conclude that although limited thyroid resection may leave occult malignancies in unresected thyroid tissue, there is no significant difference in outcome between patients with limited resection and those with near total or total thyroidectomy after a 12-year follow-up of the program. Significant differences in cancer recurrence rats may occur with longer follow-up.