It is known that pediatric inguinal hernia is caused by the incomplete closure of processus vaginalis (PV). In the case of unilateral hernia, possibile contralateral patent PV should be considered because of its delayed appearance as well as its risk of incarceration. Direct visualization of patent PV could be done by contralateral exploration or by indirect exploration through the ipsilateral opening site of the affected hernia assisted with laparoscope. A patient group (321 persons) to whom laparoscopy was not performed from March 2000 to March 2003 was analyzed and compared with a patient group (280 persons) to whom laparoscopy was performed from April 2003 to September 2005. With all 601 patients, the sex ratio (male/female) of patients was 3.8:1. The side distribution was 57.7% in the right, 32.1% in the left and 10.1% in bilateral. There was no difference of sex and side distribution between before and after laparosopy adoption. We did not find an age correlation in natural closure of the residual PV of the peritoneum. Contralateral hernia developed in 14 persons (2.5%) after the operation of unilateral inguinal hernia before laparoscope adoption. But no contralateral hernia developed after April 2003 with laparoscopy. We think that if we use laparoscopy, being a safe and accurate method, to check whether the contralateral residual PV is opened or closed, possible future contralateral operation can be avoided.

Mature cystic teratoma, commonly called dermoid cyst, is the most common benign germ cell tumor of the ovary in children. Malignant transformation is rare, approximately 2%. As laparoscopic procedures are applied widely in pediatric surgery, a female chlid with a mature cystic teratoma may be an ideal candidate for laparoscopic surgery. Two children received laparoscopic operations successfuly for lower abdominal crises, twisted adnexa. There was no operative complication. Laparoscopic approach for ovarian lesions in infancy and childhood appears to be an effective and safe method for diagnosis as well as definitive therapy.

Two cases of primary torsion of the greater omentum were described. The first patient was a 5-year-old boy who was admitted to the hospital because of severe abdominal pain for 1 day. The The clinical features were similar to perforated acute appendicitis. Laparotomy revealed a normal appendix and the greater omentum twisted around its pedicle. The second patient was a 7-year-old girl admitted to the hospital because of abdominal pain in right lower quadrant for 2 days. The clinical features were that of acute appendicitis. Laparotomy revealed a normal appendix and primary torsion of greater omentum around its pedicle. In both cases, resection of twisted omentum and incidental appendectomy were done. The microscopic findings in two cases consisted of congestion and vascular hemorrhage. Both patients recovered uneventfully. Torsion of the greater omentum, therefore, may be added to the entities to consider in the differential diagnosis of acute appendicitis.

The incidence of Meckel's diverticulum(MD) in general population has been assessed as 2 percent. The major complications of MD are bleeding, perforation, and intestinal obstruction. In spite that the complication rate of Meckel's diverticulum is relatively high(about 4.2% during a lifetime), the preoperative diagnostic rate of complicated MD is very low. Authors investigated the clinical characteristics of complicated MD to improve the diagnostic rate. 16 patients with complicated Meckel's diverticulum who were operated upon at the Department of Pediatric Surgery, Seoul National University Children's Hospital from June 1985 to December 1993 were reviewed. Among the 16 patients with complicated MD, 12 patients(75%) were under 2 year-old and male were predominant(88%). The most common complication was bleeding patients with bleeding MD (8 cases) were diagnosed preoperatively as MD. 8 patients with other complications(perforation : 4 cases, obstruction: 4 cases) could not be suspected as complicated MD except one patient who had previous history of melena. These patients were diagnosed after exploratory laparotomy under the various impression other than MD. Among 12 patients with ulcer related complications such as bleeding and perforation, heterotopic gastric mucosa was found in 11 patients. In conclusion, in any children with unexplained acute abdomen, especially under 2 years old, complicated MD must be included in differential diagnosis. In children with obscure lower gastrointestinal bleeding,^99m Tc-pertechnetate scintigraphy is a useful diagnostic tool to rule out bleeding MD.