Retrorectal tumors: A challenge for the surgeons

Retrorectal or presacral tumors are rare lesions located in the presacral area and considered as being derived from multiple embryological remnants. These tumors are classified as congenital, neurogenic, osseous, inflammatory, or miscellaneous. The most common among these are congenital benign lesions that present with non-specific symptoms, such as lower back pain and change in bowel habit. Although congenital and developmental tumors occur in younger patients, the median age of presentation is reported to be 45 years. Magnetic resonance imaging plays a crucial role in treatment management through accurate diagnosis of the lesion, the evaluation of invasion to adjacent structures, and the decision of appropriate surgical approach. The usefulness of preoperative biopsy is still debated; currently, it is only indicated for solid or heterogeneous tumors if it will alter the treatment management. Surgical resection with clear margins is considered the optimal treatment; described approaches are transabdominal, perineal, combined abdominoperineal, and minimally invasive. Benign retrorectal tumors have favorable long-term outcomes with a low incidence of recurrence, whereas malignant tumors have a potential for distant organ metastasis in addition to local recurrence.     

Size effect in resin/glass composite flexure strengths

The objective of this study was to test the hypothesis that composite restorative materials possess an elastic-brittle nature and therefore will exhibit a size effect for flexure strength data. The experimental material consisted of 20 wt% 60:40 BISGMA:TEGDMA, 10 wt% colloidal silica, and 70 wt% Sr glass and was cured by light irradiation. Two sizes of flexure specimens were fabricated: 3.2x1.6x35 mm, and 6.25x3.1x35 mm. Half of the specimens made were soaked to equilibrium weight gain in 50:50 ethanol:water. The fracture strengths were measured in four-point bending tests. The beams under load were modelled by the finite element package ABAQUS. A statistical fracture mechanics methodology embodied in a public domain computer program called CARES/LIFE, developed by NASA, utilized the ABAQUS input and the fracture strengths of the smaller specimens to predict the fracture strengths of the larger specimens. In making the computation it used an approach that combines a Weibull distribution of flaw size with Batdorf's fracture mechanical model for failure at a material flaw. Both the soaked and unsoaked specimens exhibited Weibull behaviour, with shape parameters ranging from 4.04 to 8.15. Soaking had a clearly detrimental effect on the strengths of specimens of both sizes, and produced a comparable percentage reduction in the estimated scale parameter of the fracture strength distribution. Both the soaked and unsoaked specimens also exhibited a clear and comparable size effect, i.e. the larger specimens had a fracture strength that was lower than that of the smaller specimens by roughly the same percentage. Moreover, the magnitude of the size effect was well predicted by the CARES/LIFE methodology for both the soaked and the dry specimens. The elastic-brittle character of both soaked and unsoaked composite specimens was validated by load-deflection data, the magnitude of the Weibull shape parameters of the observed fracture strength data (<10), and the observed effect of specimen size. The accuracy of CARES/LIFE in predicting the magnitude of the observed size effect in beams of two different sizes strongly suggests that CARES/LIFE will be useful for computation of failure probabilities for clinically relevant structures.     

The double-staple technique in colorectal anastomoses: a critical review.

The widespread availability and use of stapling devices have changed colorectal surgery. In 1980, Knight and Griffen developed the "double-staple" technique, using a circular stapler to transect a linear rectal staple line. This eliminated the need for a hand-sewn, distal purse string, which was sometimes difficult or even impossible to accurately place low in the pelvis. To evaluate this procedure, the authors have reviewed their results with the double-staple technique over the past 5 years. One hundred four patients underwent this procedure between 1985 and 1990 at Thomas Jefferson University Hospital (Philadelphia, PA). There were 60 men and 44 women, with a mean age of 62.4 years. Seventy-two patients underwent operation for carcinoma of the rectum or sigmoid. Thirty-five of these had preoperative radiation therapy. Other diagnoses included 1) diverticular disease, 2) rectal prolapse, 3) villous adenoma, 4) endometrial carcinoma, 5) fistula, 6) stricture, 7) Crohn's disease, 8) colonic endometriosis, 9) lymphoma, 10) ovarian carcinoma, and 11) ulcerative colitis. Incomplete "donuts" were observed in 5 patients. Diverting colostomies were performed in 23 patients, ileostomies in 3. Postoperative complications relating to the double-staple technique itself included a rectovaginal fistula in 1 patient. There were 3 clinical leaks (2.8%), all treated nonoperatively. No strictures were observed. As previously observed, the authors believe the double-staple technique offers certain advantages over traditional, hand-sewn and stapled anastomoses, for instance: 1) there is significantly less contamination, 2) the anastomosis is technically easier, and 3) bowel segments of different diameters can be easily anastomosed.     

The central action of pizotifen

The central action of the potential antidepressant drug pizotifen (Sandomigran) was studied in mice, rats and rabbits. Pizotifen in doses up to 10 mg/kg i.p. was ineffective in classic tests for antidepressant activity. It neither antagonized the effects of reserpine in rats (hypothermia, ptosis) nor potentiated the effects of amphetamine (in mice and rats), nialamide or L-dopa (in mice) on locomotor activity. However, its antidepressant activity was found in the despair test in rats.On the other hand, pizotifen inhibited the head twitch reaction induced by L-5-hydroxytryptophan in mice (ED₅₀=0.009 mg/kg, i.p.) and by 5-methoxytryptamine (+tranylcypromine) in rats (ED₅₀=0.45 mg/kg, i.p.). It also antagonized tryptamine-induced clonic convulsions of fore-paws in rats (ED₅₀=0.35 mg/kg, i.p.), and in doses of 5–10 mg/kg s.c. inhibited hyperthermia produced by LSD in rabbits. Finally, pizotifen (0.1–0.3 mg/kg, i.v.) inhibited or abolished LSD- or quipazine-induced stimulation of the hind limb flexor reflex of spinal rats; the above effect was not due to noradrenolytic action of the drug. These results suggest that pizotifen strongly blocks the central postsynaptic serotonin receptors.     

Performing Testicular or Epididymal Sperm Retrieval Prior to the Injection of hCG

Purpose: Our purpose was to determine the feasibility and efficacy of performing testicular or epididymal sperm retrieval prior to the injection of human chorionic gonadotropin (hCG). Methods: This report deals with 87 sperm-positive percutaneous epididymal sperm aspiration (PESA), percutaneous testicular sperm aspiration (PTSA), or testicular sperm extraction (TESE) cycles. All sperm retrieval procedures were performed prior to administration of hCG to the women. Retrieved spermatozoa were cultured in vitro in simple medium for approximately 40 hr prior to intracyto-plasmic sperm injection. Results: In all but one cycle in which TESE was performed for nonobstructive azoospermia, motile sperm were available for ICSI. The overall fertilization rate was 53%. Pregnancy rate per transfer and implantation rate per embryo were 41.2 and 15.7%, respectively. Conclusions: Satisfactory fertilization and pregnancy rates can be achieved when PESA, PTSA, or TESE is performed prior to the injection of hCG followed by in vitro culture of spermatozoa approximately 40 hr before ICSI. Scheduling of testicular or epididymal sperm retrieval cases in this way appears to ease the workload on laboratory and operating room personnel. Furthermore, withholding hCG when sperm is absent may obviate the unnecessary risk of ovarian hyperstimulation when spermatozoa cannot be retrieved.     

Efficacy of vaginal misoprostol before hysteroscopy for cervical priming in patients who have undergone cesarean section and no vaginal deliveries

We wanted to investigate the effect of misoprostol administered vaginally before operative hysteroscopy on cervical dilation, complications, and failure rates in patients who have undergone cesarean section and who have never delivered vaginally. Sixty patients who had undergone cesarean section, who had never delivered vaginally before, and were about to undergo hysteroscopy for various intrauterine lesions were included in this randomized controlled study. Thirty-two patients in the study group were given misoprostol 400 microg, and 28 patients in the control group were given placebo (hexetidine pill) vaginally twice, 6 and 12 hours before the procedure. Primary endpoints were cervical width detected with Hegar dilators and complication and failure rates. Mean cervical width was greater in patients in the study group (6.5 +/- 0.8) than it was in patients in the control group (3.0 +/- 0.6), (p = .0001). Complication and failure rates were lower in patients in the study group (p = .01). Administration of vaginal misoprostol before hysteroscopy proved to be effective in cervical ripening and in reducing complication and failure rates.     

Effect of honey on intestinal morphology, intraabdominal adhesions and anastomotic healing

In the present study, attempts have been made to determine the effects of honey on intestinal morphology, postoperative adhesions, and the healing of colonic anastomoses in the rats after colonic resection and anastomosis. Thirty-six rats were randomly divided into three groups each including 12 animals. Colonic resection and anastomosis were performed on all animals. Rats were fed with standard rat chow in group I, standard rat chow plus 10 g/kg/day honey in group II and artificial honey including the same caloric amount with honey in group III. Adhesion scores, bursting pressures and histopathological examinations were evaluated. Colonic bursting pressures of honey group were significantly better than control and artificial honey groups. Histological analysis of anastomotic site showed that submucosa and muscularis propria were nearly filled with granulation tissue and regular fibrin matrix in honey group. There was statistically significant difference between the adhesion scores of honey vs artificial honey and control groups. The scores of histological changes of ileum in honey group were significantly different from other groups. These results indicate a protective role of honey against intraabdominal adhesions and anastomotic dehiscence.