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L L Ooi

Publications and source records attributed to L L Ooi.

At least 19 recordsLinked to original sources
PubMed1999

Bile duct injuries during laparoscopic cholecystectomy: a collective experience of four teaching hospitals and results of repair.

BACKGROUND: Laparoscopic cholecystectomy has been performed in Singapore since 1990 and, up until the end of 1997, a total of 4445 procedures had been performed in the four major teaching hospitals. Although bile duct injuries were thought to have increased following the introduction of laparoscopic cholecystectomy, there have been no reviews done on the incidence of these injuries in the Singapore context. METHODS: The present retrospective review aimed to audit the rate of bile duct injuries in the four major teaching hospitals in Singapore and to document the results of management of these injuries. RESULTS: Of the 4445 procedures performed, there were 19 (0.43%) cases of bile duct injuries. These involved the common hepatic duct (n = 8), common bile duct (n = 10), and the right hepatic duct (n = 1). The underlying gall bladder pathology included non-inflamed gall bladders (n = 10), acute cholecystitis (n = 4), Mirrizzi's syndrome (n = 3) and mucocele of the gall bladder (n = 2). Transection of the duct accounted for the majority of the injuries. Eleven bile duct injuries were identified at the time of operation. These were primarily repaired over a T tube (n = 4) or by a bilio-enteric bypass (n = 7). The remainder were diagnosed at a median of 7 days (range: 1-556 days) after surgery with a presentation of jaundice or pain. These were repaired by bilio-enteric anastomosis (n = 7) and closure over a T tube (n = 1). Three patients developed strictures subsequently, two following bilio-enteric repair after delayed diagnosis and one following immediate primary repair over a T tube. One patient developed intrahepatic stones and required a left lateral segmentectomy. CONCLUSIONS: The experience of a 0.43% bile duct injury rate is comparable to the best results from most large series in the West. Inflammation at Calot's triangle is an important associated factor for injury. Early recognition and prompt repair affords good results, and hepaticojejunostomy is recommended as the repair of choice.

Adult↗
PubMed1999

An animal model for the study of hepatic stellate cell and hepatocellular carcinoma interaction.

The recognition of hepatic stellate cells (HSC) around and within hepatocellular carcinoma (HCC) in human livers has generated interest in the interactions between HSC and HCC. We explored the possibility of creating an animal model to allow in vivo investigations of this interaction. Eighteen adult Buffalo rats were inoculated with 1 x 10(6) cells obtained from cultures of Morris 7777 hepatoma cell line (ATCC). The rats were sacrificed at 2-, 3-, and 4-week intervals. Identification of activated HSC was with immunohistochemistry for alpha-smooth muscle actin (alpha-SMA). There was 100% survival of all animals until sacrifice. Tumour formation occurred in 94.4% of rats, and was of a good size by two weeks. Expression of alpha-SMA was observed around and within all HCC, but absent from normal tissue, and this showed colocalisation with collagen deposition. These findings are consistent with those previously reported in resected HCC in humans. The high survival, good tumour yield, consistent generation of activated HSC around the tumours, and similarities in histological appearance to the human HSC-HCC distribution pattern, make this a reliable animal model for in vivo studies on HSC-HCC interaction.

Actins↗
PubMed1999

3rd Yahya Cohen Lecture: the role of the myofibroblast-like cell in hepatocellular carcinoma--host defence?

Hepatocellular carcinoma is a common cancer in Asia with a poor prognosis. Tumour encapsulation has been shown to be a good, independent prognostic factor. The main cell in the liver responsible for extracellular matrix formation is the hepatic stellate cell, and this was investigated as the cell type responsible for encapsulation. This lecture discusses the role of hepatic stellate cells in hepatocellular carcinoma, in particular with tumour encapsulation as a host defence mechanism. The study involved four phases: (1) comparing encapsulated tumours with non-encapsulated tumours, (2) comparing with metastatic tumours to the liver, (3) creation of an animal model, and (4) investigating known cytokines with hepatic stellate cell stimulating activity. The results showed that the hepatic stellate cells were responsible for tumour encapsulation and that this was impaired in non-encapsulated tumours and in metastatic tumours. A successful animal model was created which allowed further work. However, the known cytokines that normally stimulate hepatic stellate cells were not shown to be involved in tumour encapsulation, suggesting that an unknown factor may be involved.

Animals↗
PubMed1998

Cystic tumours of the pancreas: a diagnostic dilemma.

BACKGROUND: Cystic neoplasm of the pancreas is an uncommon entity that encompasses a range of tumours with varying potential for malignancy. These tumours are frequently misdiagnosed as pseudocysts and are inappropriately managed. METHODS: A retrospective review was undertaken of 18 cases of cystic tumours of the pancreas over an 8-year period in two large hospitals in Singapore. RESULTS: All patients were Asian, with a younger age group (mean 43.5 years) and a lesser degree of female predominance (3.5:1 ratio) compared to other series. Pain was the most common symptom. Pre-operative diagnosis using ultrasound and computed tomography was not diagnostic in half of the cases and misdiagnosed as pseudocyst in a sixth. There were five serous cystadenomas, four mucinous cystadenomas, two mucinous cystadenocarcinomas, one mucinous cystadenocarcinoma with cystic degeneration in a ductal adenocarcinoma, three Frantz tumours, one acinar cell tumour, one glucagonoma, and one benign epithelial cyst. Two-thirds of tumours were malignant or had the potential to become malignant. Resection was curative in all cases, and no recurrence was noted at a mean follow-up of 34.5 months. CONCLUSIONS: The difficulties with pre-operative diagnosis, the high incidence of tumours with potential malignancy, and the good outcome with resection, suggest that all suspected cystic tumours of the pancreas should be resected.

Adenocarcinoma↗
PubMed1997

Human liver transplant perfusate: an abundant source of donor liver-associated leukocytes.

In vitro studies designed to examine the mechanisms of immune tolerance after liver transplantation in humans have been hampered by the difficulty in obtaining sufficient numbers of donor liver-associated leukocytes (LALs). We have investigated whether the ex vivo perfusion of donor livers releases a population of LALs that can be readily retrieved from the waste fluid. The mean number of cells recovered after Ficoll-Hypaque density-gradient separation was 2.6 +/- 0.5 x 10(8) cells, with a viability of 94% +/- 2%. The perfusate lymphocytes comprised mainly T cells (39% +/- 2%) with a very low CD4/CD8 ratio and natural killer (NK) cells (56% +/- 6%) with an increase in the proportion of the CD3-CD56+CD16- subset. The activation marker CD69 was present on the majority of the perfusate lymphocytes. These are the phenotypic characteristics that have been previously reported for lymphocytes isolated from hepatic sinusoids. In mixed lymphocyte reactions, the perfusate cells showed a marked increase in the ability to stimulate allogeneic responder cells, resulting in 353% +/- 78% (P = .003) greater incorporation of [3H]thymidine in responder cells when compared with stimulation by donor peripheral blood mononuclear cells. The results show that large numbers of viable donor lymphocytes can be readily isolated from the liver perfusate solution. These cells have the characteristics of liver-associated lymphocytes with a predominance of activated NK and CD8+ T cells. This population can now be used in in vitro assays to elucidate the influence of donor leukocytes on the development of graft acceptance.

Humans↗
PubMed1997

Splenic abscesses from 1987 to 1995.

BACKGROUND: Isolated splenic abscesses is an uncommon clinical entity that is being increasingly recognized as a cause of intraabdominal sepsis in a wide variety of clinical situations, and involving a wide range of organisms. The increasing incidence of immunosuppressed states in this decade due to the use of chemotherapy for oncology, immunosuppression therapy for transplantation, and acquired immune deficiency syndrome, has changed the disease pattern of splenic abscesses. METHOD: Data from 287 cases reported in the English literature between 1987 and 1995 were collected, analyzed, and compared with two previous reviews of cases reported before 1987. RESULTS: Staphylococcus, Salmonella, and Escherichia coli are the most common organisms cultured. Immunosuppressed states were present in 33.5% of cases, with intravenous drug abuse and acquired immune deficiency syndrome accounting for half these cases. Computerized tomography and ultrasonography are diagnostic, with a sensitivity of 92.2% and 87.2%, respectively. Nonoperative management has a success rate of less than 65%, but salvage splenectomy does not increase mortality compared with splenectomy as initial therapy. CONCLUSIONS: Splenic abscesses are increasingly recognized with immunosuppressed states. Percutaneous radiologically guided drainage may be suitable in some cases, but splenectomy with appropriate antibiotics is the definitive treatment.

Abscess↗
PubMed1996

Laparoscopic hernia repair in Singapore--views from a cross-section of surgeons.

Laparoscopic cholecystectomy was introduced into Singapore in 1990, and has since replaced conventional cholecystectomy as the treatment of choice for gallstone disease in most situations. In contrast, laparoscopic hernia repair introduced two years later in the same wave of enthusiasm, was received with scepticism and much less acceptance. A survey of 27 general surgeons in three large institutions in Singapore was performed to analyse this observation. The majority of surgeons felt that laparoscopic hernia repair (i) had limited applications, mainly for bilateral and recurrent hernias, (ii) was not completely established as a technique, requiring refinement in the procedure, (iii) was costly, and (iv) did not have objective evidence of long-term benefits over conventional hernia repair.

Cross-Sectional Studies↗
PubMed1996

Training in laparoscopic surgery--have we got it right yet?

Training in laparoscopic surgery started with short two to three-day courses, frequently unstructured and unaccredited, in a rush to provide surgeons with supposedly adequate training in laparoscopic techniques before performing laparoscopic cholecystectomy in patients. The high incidence of complications with this situation led to guidelines on training, credentialling and auditing being drawn up by several responsible professional bodies. Almost a decade after the introduction of laparoscopic cholecystectomy, the situation with training in laparoscopic surgery is still unresolved in many countries. This article reviews the current opinion on training in laparoscopic surgery, and presents the various teaching models and techniques employed to facilitate this process. Training in laparoscopic surgery should form part of the general surgery training programme, and should involve a combination of short introductory courses with hands-on animal models, and a period of preceptorship following this.

Animals↗
PubMed1995

Kimura's disease involving the median nerve: a case report.

Kimura's disease is an uncommon chronic inflammatory process of obscure origin. It is more common among Orientals and affects particularly the young male. Sites of predilection include the head and neck region, primarily the subcutaneous tissue and dermis. Unusual sites of occurrence that have been reported include the kidney, the orbit, the ear and the spermatic cord. Kimura's disease involving a major nerve bundle has not been described, and we report here the findings of a case of histologically proven Kimura's disease of the median nerve occurring in a 21-year-old Chinese girl. Typical diagnostic histological features of Kimura's disease in contrast to angiolymphoid hyperplasia, and the treatment options for Kimura's disease are also described.

Adult↗
PubMed1994

Laparoscopic assessment and orchidectomy for the undescended testis.

Cryptorchidism is the most common disorder of male sexual differentiation. Pre-operative assessment and localization of undescended testes by various investigatory modalities have been of limited clinical value. The recent use of diagnostic and therapeutic laparoscopy for undescended testis peri-operatively has been shown to be safe and informative in the planning of appropriate surgical management. The authors' initial experience with this procedure, for five patients with unilateral undescended testis, is presented.

Adolescent↗
PubMed1994

Laparoscopic marsupialization of liver cysts.

The majority of benign, non-parasitic liver cysts are asymptomatic. Surgical treatment is reserved for symptomatic patients and frequently involves partial excision or marsupialization via a laparotomy. Surgery is occasionally offered for asymptomatic large cysts, where complications of cyst rupture, intra-cystic bleeding and infection are more common. The authors describe three cases of symptomatic liver cysts that were effectively marsupialized laparoscopically with good results.

Adult↗
PubMed1994

Video-assisted endoscopic thoracic sympathectomy in the management of intractable palmar hyperhydrosis.

Minimally invasive endoscopic surgical techniques have revolutionised patient management. We present our findings in our first 10 cases of bilateral video-assisted endoscopic thoracic sympathectomy in the management of intractable palmar hyperhydrosis including the first such procedure in Singapore. We have found the procedure to have minimal morbidity, good patient acceptance and all patients have remained with dry palms.

Adult↗
PubMed1994

Thoracoscopic vagotomy for peptic ulcer disease--report of two cases.

Thoracoscopic vagotomy is a well-established technique in the management of recurrent peptic ulceration after previous abdominal vagotomy. The procedure allows an easy approach to the vagus nerves without having to dissect through dense adhesions from previous surgery. With thoracic vagotomy, the main morbidity is postoperative pain from the thoracotomy incision and rib spreading. Advances in endoscopic camera systems and instrumentation allow thoracic vagotomy to be safely and effectively accomplished by thoracoscopic surgery techniques, with reduced postoperative pain. We describe our experiences with thoracoscopic vagotomy in two cases of recurrent peptic ulceration.

Adult↗
PubMed1993

Primary papillary carcinoma in a thyroglossal cyst--a case report.

A benign thyroglossal cyst is a common clinical condition and is second only to a cervical lymph node as the most common cause of a solitary neck swelling. Primary carcinoma of a thyroglossal cyst, however, is rare and has been described in only 115 cases in the literature. The malignant cysts are clinically difficult to differentiate from benign lesions and the diagnosis often rests on histopathological examination. Before initiating treatment, primary papillary carcinoma of the thyroid gland must be excluded. The treatment options range from simple excision to a Sistrunk operation with concurrent cervical lymph node dissection. We describe here a case of papillary carcinoma of a thyroglossal cyst and review the 115 reported cases.

Adult↗
PubMed1992

Splenic abscess.

Isolated splenic abscess is an uncommon condition. Seven cases seen between 1980 and 1990 are reviewed. The clinical presentation is non-specific and diagnosis is usually delayed. Computerized tomography allowed for accurate diagnosis in all cases. Pseudomonas species as a causative organism is reported to be rare, but were present in three of the present cases. Antibiotic therapy alone is insufficient and splenectomy remains the treatment of choice.

Abscess↗
PubMed1992

Laparoscopy-guided percutaneous cholecystolithotomy: an evolving technique.

Gall-bladder conservation therapy has been evolving during the past decade. Popular techniques of conservative therapy are extracorporeal shock wave lithotripsy (ESWL) and medical dissolution therapy. The limitations of these procedures have prompted a search for alternative techniques, particularly in relation to percutaneous stone extraction. The cases of four patients with symptomatic gallstones who underwent percutaneous cholecystolithotomy under laparoscopic guidance are reported. The gall-bladder was punctured with a long needle and the tract dilated so that a nephroscope could be introduced. Three cases required stone fragmentation by an ultrasonic lithotripter before removal. Postoperative recovery was uneventful in all cases.

Adult↗