Anterior cruciate ligament fascia lata allograft reconstruction: progressive histologic changes toward maturity.

Biopsy samples were obtained arthroscopically from 21 patients who had undergone anterior cruciate ligament (ACL) reconstruction using rolled, freeze-dried fascia lata allograft in order to evaluate progressive histologic changes toward maturation. The study period was 3-20 months postoperation. The mean age (+/- SEM) was 31.9 +/- 10.3. Histomorphometry was used for quantitative evaluation. Arthroscopic examination showed fully synovialized allografts in all patients. Varying degrees of degenerative tissues were observed histologically. There was a significant, direct correlation between the percentage of polarized tissue and the maturity of the biopsy specimen (r = 0.9; p < 0.04). The mean area of polarization in the postrehabilitation period (10-20 months) was significantly higher (p < 0.01) than in the rehabilitation period (3-20 months). Overall, there was a progressive decrease in cellularity and vascularity as the allograft matured. Compared with the biopsy samples of normal ACLs, the allograft was still undergoing maturation 20 months postoperatively.

Exocrine pancreatic function following intraoperative irradiation of the canine pancreas.

Twenty-four beagles received intraoperative irradiation (IORT) with 6 meV electrons to the pancreas and the duodenum. Intraoperative irradiation doses of 17.5 to 40 Gy were given. Billroth II gastrojejunostomy was done to bypass the irradiated duodenum. Six control dogs received only the Billroth II surgery. Two weeks postoperatively, irradiated dogs were given 50 Gy of 6 MV X radiation (external-beam radiation [EBRT]) to the pancreas and duodenum in 2 Gy fractions over a 5-week period. Dogs were monitored clinically and exocrine pancreatic function was evaluated using an N-benzoyl-l-tyrosyl-para-aminobenzoic acid (BT-PABA) test between 3 and 135 days postoperatively. Necropsies were performed on the dogs at 135 days postoperatively. The degree of gross pancreatic atrophy in the irradiated group was dose related. The mean percentage of normal acinar cells correlated with IORT doses and para-aminobenzoic acid (PABA) values (P less than 0.1). Weight loss was significantly greater in the irradiated dogs compared to the control (P less than 0.05) and the mean percentage of body weight loss correlated with the mean PABA values (P less than 0.01). In this study, the use of the BT-PABA test to evaluate progressive exocrine pancreatic function following IORT and EBRT showed an expected trend. A progressive decrease in exocrine pancreatic function in the irradiated dogs as indicated by plasma PABA levels may have been partly due to late radiation damage to acinar cells, secondary to vascular and ductular damage. At 135 days postoperatively none of the dogs showed clinical signs of exocrine pancreatic insufficiency and the plasma PABA levels were within the normal presurgical range. The progressive decrease in plasma PABA levels indicated a potential for the late development of exocrine pancreatic insufficiency. The BT-PABA test could be useful for evaluating the progressive decrease in exocrine pancreatic function and residual radiation injury to the pancreas. Because the exocrine deficiency can be managed with replacement therapy, pancreatic injury may not be a serious complication after doses of less than 30 Gy IORT with 50 Gy EBRT. Data from this study are in agreement with previous clinical and experimental reports that the duodenum is dose-limiting for IORT. Doses of 20 Gy IORT or less plus 50 Gy EBRT for treatment of carcinoma of the pancreas may not result in serious long-term complications due to radiation injury of the duodenum.

Billroth II gastrojejunostomy in dogs. Stapling technique and postoperative complications.

Billroth II gastrojejunostomy was performed with surgical staplers in 6 dogs that were not irradiated and in 11 dogs that subsequently received radiation to the pancreas and proximal part of the duodenum. The dogs were monitored clinically for 135 days and then euthanatized and necropsied. Each gastrojejunostomy site was preserved in formalin and the stomal diameter was measured. No mechanical complications were encountered with the use of surgical staplers and no leakage was observed at the staple closure sites before abdominal closure. All dogs vomited approximately 100 ml of coagulated blood 4 to 8 hours after surgery, and 300 to 400 ml of brown fluid after approximately 24 hours. Vomiting was the most common clinical finding after the first 24 hours. Vomiting was subjectively graded from 1 to 3 with grade 1 representing the least severe problem and grade 3 the most severe. Grade 1 vomiting occurred in 12 of 16 dogs that survived 135 days; in the other four dogs, vomiting was classified as grade 2 or 3. All dogs with grade 1 vomiting had stomal diameters of 1.7 to 2.9 cm (mean, 2.2 +/- 0.4 cm standard deviation). Dogs with grade 2 or 3 vomiting had stomal diameters of 2.2 to 4.0 cm (mean, 3.2 +/- 0.8 cm standard deviation). The difference was statistically significant (p less than 0.005). The percentage of weight gained or lost was recorded for each dog. Two nonirradiated dogs gained body weight, whereas the other nonirradiated dogs and all irradiated dogs lost body weight.(ABSTRACT TRUNCATED AT 250 WORDS)

Pathologic response of the pancreas and duodenum to experimental intraoperative irradiation.

The pancreas and duodenum of 24 beagle dogs were given intraoperative irradiation (IORT) with 6 MeV electrons. The dose range was 17.5 Gy to 40 Gy. Billroth II gastrojejunostomy was performed on all dogs prior to irradiation. Six control dogs received only Billroth II surgery. Starting 2 weeks after surgery, dogs in the irradiation groups were given 50 Gy 6 MV X rays external beam radiation therapy (EBRT) to the pancreas and duodenum. The total dose of 50 Gy was given in 2 Gy fractions over 5 weeks. Dogs were monitored for 135 days then necropsied. Gross and histopathologic changes in the pancreas and duodenum were evaluated and quantitative analysis of pancreatic lesions done. Duodenal ulcers were found following 32.5 Gy and 40 Gy IORT. The pancreases were atrophic in irradiated dogs and exocrine pancreatic insufficiency occurred in one dog given 25 Gy. Gross pancreatic atrophy correlated with IORT dose. Histopathologic evidence of radiation damage to the pancreas was observed in acinar cells. Islet cell lesions were not apparent. There was pancreatic fibrosis and damage to blood vessels and ducts. Dose-response relationships were observed for the index of damage to the pancreas as a whole, for pancreatic fibrosis and a decrease in normal acinar cells. Although 25 Gy IORT plus 50 Gy EBRT was tolerated by the duodenum to 135 days, these doses may cause later pancreatic injury as an expression of damage to blood vessels and ducts. Exocrine pancreatic insufficiency and diabetes mellitus may thus represent potential late complications of IORT following 25 Gy or higher doses.