Wei-Keat Cheah

Loss of Parafibromin Immunoreactivity Is a Distinguishing Feature of Parathyroid Carcinoma

Purpose: A reliable method for diagnosing parathyroid carcinoma has remained elusive over the years, resulting in its under-recognition and suboptimal therapy. Obtaining an accurate diagnosis has become an even more pressing matter with recent evidence that germline HRPT2 gene mutations are found in patients with apparently sporadic parathyroid carcinoma. There is a high prevalence of HRPT2 gene mutations and biallelic inactivation in parathyroid carcinoma. We hypothesize that loss of parafibromin, the protein product of the HRPT2 gene, would distinguish carcinoma from benign tissue. Experimental Design: We generated a novel antiparafibromin monoclonal antibody and performed immunostaining on 52 definite carcinoma specimens, 6 equivocal carcinoma specimens, 88 benign specimens, and 9 hyperparathyroidism-jaw tumor (HPT-JT) syndrome-related adenomas from patients with primary hyperparathyroidism from nine worldwide centers and one national database. Results: We report that the loss of parafibromin nuclear immunoreactivity has 96% sensitivity [95% confidence interval (CI), 85–99%] and 99% specificity (95% CI, 92–100%) in diagnosing definite carcinoma. Inter-observer agreement for evaluation of parafibromin loss was excellent, with unweighted kappa of 0.89 (95% CI, 0.79–0.98). Two equivocal carcinomas misclassified as adenomas were highlighted by parafibromin immunostaining. One of these tumors has since recurred, satisfying criteria for a definite carcinoma. Similarly, eight of nine HPT-JT syndrome-related adenomas showed absent nuclear immunoreactivity. Conclusions: Parafibromin is a promising molecular marker for diagnosing parathyroid carcinoma. The similar loss of parafibromin immunoreactivity in HPT-JT syndrome-related adenomas suggests that this is a pivotal step in parathyroid tumorigenesis.

Laparoscopic versus open ventral hernia mesh repair: a prospective study

BackgroundAn incisional hernia develops in 3% to 13% of laparotomy incisions, with primary suture repair of ventral hernias yielding unsatisfactory results. The introduction of a prosthetic mesh to ensure abdominal wall strength without tension has decreased the recurrence rate, but open repair requires significant soft tissue dissection in tissues that are already of poor quality as well as flap creation, increasing complication rates and affecting the recurrence rate. A minimally invasive approach was applied to the repair pf ventral hernias, with the expectation of earlier recovery, fewer postoperative complications, and decreased recurrence rates. This prospective study was performed to objectively analyze and compare the outcomes after open and laparoscopic ventral hernia repair.MethodsThe outcomes for 50 unselected patients who underwent laparoscopic ventral hernia repair were compared with those for 50 consecutive unselected patients who underwent open repair. The open surgical operations were performed by the Rives and Stoppa technique using prosthetic mesh, whereas the laparoscopic repairs were performed using the intraperitoneal onlay mesh (IPOM) repair technique in all cases.ResultsThe study group consisted of 100 patients (82 women and 18 men) with a mean age of 55.25 years (range, 30–83 years). The patients in the two groups were comparable at baseline in terms of sex, presenting complaints, and comorbid conditions. The patients in laparoscopic group had larger defects (93.96 vs 55.88 cm2; p = 0.0023). The mean follow-up time was 20.8 months (95% confidence interval [CI], 18.5640–23.0227 months). The mean surgery durations were 90.6 min for the laparoscopic repair and 93.3 min for the open repair (p = 0.769, nonsignificant difference). The mean postoperative stay was shorter for the laparoscopic group than for the open hernia group (2.7 vs 4.7 days; p = 0.044). The pain scores were similar in the two groups at 24 and 48 h, but significantly less at 72 h in the laparoscopic group (mean visual analog scale score, 2.9412 vs 4.1702; p = 0.001). There were fewer complications (24%) and recurrences (2%) among the patients who underwent laparoscopic repair than among those who had open repair (30% and 10%, respectively).ConclusionsThe findings demonstrate that laparoscopic ventral hernia repair in our experience was safe and resulted in shorter operative time, fewer complications, shorter hospital stays, and less recurrence. Hence, it should be considered as the procedure of choice for ventral hernia repair.

Early experience with laparoscopic radical gastrectomy for advanced gastric cancer.

Use of the laparoscopic approach for the management of gastric cancer is still in the developmental phase. The authors present their experience with laparoscopic radical gastrectomy for advanced gastric cancer. Between September 1997 and August 1999, four laparoscopic gastrectomies for gastric carcinoma were performed on two male and two female patients (mean age, 61.5 years). One D2 total radical gastrectomy and three D2 subtotal distal gastrectomies were performed, using a totally laparoscopic approach. Mean operative time was 210 minutes. There were no intraoperative complications. All four patients recovered uneventfully from surgery and began oral feeding on the third postoperative day. Median postoperative stay was 7 days (range, 6–9). All patients were alive 8 months to 3 years after the operation, with no cancer recurrences. This series shows that laparoscopic radical gastrectomy for moderately advanced cancers can produce good results in terms of safety and oncologic adequacy.

Laparoscopic appendectomy for perforated appendicitis

Although laparoscopic appendectomy for uncomplicated appendicitis is feasible and safe, its application to perforated appendicitis is uncertain. A retrospective study of all patients with perforated appendicitis from 1992 to 1999 in a university hospital was performed. A series of 231 patients were diagnosed as having perforated appendicitis. Of these patients, 85 underwent laparoscopy (LA), among whom 40 (47%) required conversion to an open procedure. An open appendectomy (OA) was performed in 146 patients. The operating time was similar for the two groups. Return of fluid and solid diet intake were faster in LA than OA patients (p<0.01). Postoperative infections including wound infections and abdominal abscesses occurred in 14% of patients in the laparoscopy group and in 26% of those with OA (p<0.05). The surgeon’s experience correlated with the conversion rate. Laparoscopic appendectomy is associated with a high conversion rate for perforated appendicitis. If successful, it offers patients faster recovery and less risk of infectious complications.RésuméAlors que l’appendicectomie par laparoscopic pour appendicite non compliquée est faisable et sûre, son rôle dans l’appendicite perforée reste incertain. On a analysé rétrospectivement les résultats chez tous les patients traités pour appendicite perforée entre 1992 et 1999 dans un service de chirurgie d’un hôptial universitaire: 231 patients ont ainsi été inclus dans cette étude. Quatre-vingt-cinq patients ont eu une laparoscopic (LA): 40 patients (47%) ont nécessité une conversion à la voie tradtionnelle. Une appendicectomie par voie traditionnelle (OA) a été réalisée chez 146 patients. La durée de l’intervention était similaire entre les deux groupes. La reprise d’alimentation orale et solide a été plus rapide dans le groupe LA par rapport au groupe OA (p<0.01). On a noté des complications infectieuses, y compris des infections pariétales et des abcès intra-abdominaux chez 14% dans le groupe L, comparé à 26% pour le groupe O (p<0.05). L’expérience du chirurgien a été corrélée directement avec le taux de conversion. L’appendicectomie laparoscopique est associée à un taux élevé de conversion en raison de l’appendicite perforée. En cas de succès, la récupération est plus rapide et il y a moins de risque de complications infectieuses.ResumenMientras que la apendicectomía laparoscópica es posible y segura en las apendicitis no complicadas, el papel de la laparoscópia en el tratamiento de la apendicitis perforada está muy controvertido. En un hospital universitario se efectuó un estudio retrospectivo de todos aquellos casos de apendicitis perforada, intervenidos entre 1992 y 1999. 231 pacientes ftieron diagnosticados de perforación apendicular. 85 fueron tratados por laparoscópia (LA) pero 40 (47%) requirieron reconversión a cirugía abierta. Con apendicectomía abierta (OA) se trataron 146 enfermos. La duración de la operación fue similar en ambos grupos. La iniciación de la ingesta de líquidos y sólidos fue más precoz en el grupo LA que en el OA (p<0.01). Infección postoperatoria que comprende tanto la de la herida como abscesos abdominales, se constató en el 14% de los pacientes del grupo LA y en el 26% de los del grupo OA (p<0.05). La experiencia del cirujano se correlacionó directamente con la tasa de reconversión. Ésta es mucho más frecuente en el tratamiento laparoscópico de las apendicitis perforadas. Si la apendicectomía laparoscópica puede realizarse satisfactoriamente el paciente se recuperará con más rapidez y el riesgo de complicaciones infecciosas será menor.

Needlescopic Thoracic Sympathectomy: Treatment for Palmar Hyperhidrosis

BACKGROUND Open thoracic sympathectomy has been the established option for patients with essential hyperhidrosis. Recently, video-assisted endoscopic sympathectomy has provided a simple, safe, reliable, and cost-effective alternative to the earlier technique. With advances in instrumentation, performing the procedure through 2-mm and 3-mm needlescopic ports is now possible. The authors evaluate the effectiveness of so-called needlescopic thoracic sympathectomy for the treatment of primary hyperhidrosis. METHODS Thirty five consecutive patients with a mean age of 24 years, including 23 men and 12 women, underwent bilateral needlescopic thoracic sympathectomies at the National University Hospital of Singapore. RESULTS The mean operative duration was 56 minutes, and the mean hospital stay was 1.2 days. In no patient did Horners syndrome or significant pneumothorax develop. The rate of success, defined as completely dry hands, was 97%. Two patients had unilateral recurrences that responded well to repeat needlescopic sympathectomies. We performed a total of 72 sympathectomies. CONCLUSIONS Our study demonstrates that the use of miniature port access sites produces excellent medical and cosmetic results and is associated with a short hospital stay and low risk of complications.

Comparing T2 and T2-T3 ablation in thoracoscopic sympathectomy for palmar hyperhidrosis: a randomized control trial

BackgroundThoracoscopic sympathectomy is a useful therapeutic option for palmar hyperhidrosis. Surgeons differ in the level of the sympathetic chain ablated. This study aimed to compare the blockade of the T2 with levels T2 and T3 to verify the effectiveness of different ablation levels in relieving hyperhidrosis symptoms.MethodsFor patients undergoing bilateral thoracoscopic sympathectomy for palmar hyperhidrosis, T2–T3 ablation is performed bilaterally. In our series, 25 consecutive patients were blindly randomized to undergo unilateral T2 and T3 ablation followed by contralateral ablation of level T2 only. The patients were followed up and analyzed for comparison of symptoms bilaterally, compensatory hyperhidrosis, and levels of satisfaction postoperatively.ResultsThe study group consisted of 25 patients with a male:female ratio of 3:2 and a mean age of 32 years (range, 19–50 years). The mean operative time was 35 min. The patients were followed up for a mean period of 23 months (range, 2–65 months). All 25 patients confirmed that their palmar sweating resolved postoperatively, with both palms equally dry. Of the 25 patients, 20 (80%) complained of compensatory hyperhidrosis, which also was bilaterally symmetric. The areas involved were trunk (80%), lower limbs (32%), and armpits (12%). Overall, 80% of the patients were very satisfied with the procedure. The remaining 20% experienced mild to moderate compensatory hyperhidrosis, which did not seem to affect their lifestyle.ConclusionThe findings show that T2 ablation in thoracoscopic sympathectomy for palmar hyperhidrosis is as effective as T2–T3 ablation in terms of symptomatic relief, recurrence, compensatory hyperhidrosis, and patient satisfaction.

Laparoscopic Management of Acute Small Bowel Obstruction

BACKGROUND Conventional surgical management of acute small bowel obstruction involves laparotomy. The laparoscopic approach has not been favoured due to the presumed increased risk of bowel injury. METHODS A retrospective review of our experience of laparoscopic management of acute small bowel obstruction was undertaken. Nine patients were identified from 1997 to 2003. The aetiology of obstruction was identified laparoscopically in all cases. Eight cases were caused by bands or local adhesions and one patient had a bezoar. RESULTS Laparoscopic treatment was successful in 78% of patients including one laparoscopy-assisted procedure. Conversion to laparotomy was performed in two patients, one due to difficult adhesiolysis and one due to iatrogenic bowel injury during adhesiolysis. The mean operating time was 74 minutes. There were no postoperative complications and the mean length of hospital stay was 4.3 days. CONCLUSION This small series demonstrates that laparoscopy can serve as a good diagnostic tool as well as treatment of acute small bowel obstruction. In an appropriately selected patient, laparoscopic management of small bowel obstruction is a feasible therapeutic approach and appears to convey the benefits of a short postoperative hospital stay, reduced postoperative complications and possibly reduced subsequent adhesion formation.

Needlescopic or minisite cholecystectomy.

Abstract. Needlescopic or minisite cholecystectomy is laparoscopic cholecystectomy done through tiny ports from 1.4 mm to 3 mm in size. This refinement of conventional laparoscopic cholecystectomy reduces further the invasiveness of the operation and gives an improved cosmetic effect. This series describes the result of 36 needlescopic cholecystectomies done between February 1996 and April 1997. Patients with acute cholecystitis were excluded. There were two conversions to conventional laparoscopic surgery and no conversions to open surgery. Thirty-four patients were successfully treated by this technique. Analgesic consumption and cosmetic result was superior compared to a previous published series of conventionally done cases in the same department.

Telesurgical laparoscopic cholecystectomy between two countries.

Telesurgery is a form of operative videoconferencing in which a remotely located surgeon observes a procedure through a camera and provides visual and auditory feedback to the operative site. With the use of more robotic devices in laparoscopic surgery, various forms of telesurgery have been tried. We describe the first two international telesurgical, telementored, robot-assisted laparoscopic cholecystectomies performed in the world, between the Johns Hopkins Institute, Baltimore, Maryland, USA, and the National University Hospital, Singapore.

Improvements in health care for patients undergoing thyroidectomy.

OBJECTIVE In this study, we evaluated the effect on cost and clinical outcome of the implementation of departmental subspecialization and a clinical care pathway for patients undergoing thyroidectomy. METHODS Subspecialization and a clinical thyroidectomy pathway were implemented in 2001 at the Department of Surgery, National University Hospital, Singapore. A total of 150 patients (Group A) who served as controls were compared with 143 patients who were managed after implementation of subspecialization and the clinical thyroidectomy pathway (Group B). Length of stay, postoperative complications and cost per patient were compared between the two groups. RESULTS The mean age was 46 years and females comprised 77% of all patients. The mean length of hospital stay was shorter in Group B (1.9 days) compared with Group A (3.3 days; p < 0.001). The mean hospital charges also fell significantly after implementation, at 3,524 dollars per patient in Group B compared with 3,929 dollars in Group A (p = 0.003). There was no difference in morbidity between the two groups (2.0% and 1.4% in Groups A and B, respectively). CONCLUSION This study confirms that length of hospital stay and hospital costs are effectively reduced through the combination of subspecialization and a clinical pathway for patients undergoing thyroidectomy. Subspecialty units and pathways reduce variation in patient care. This effectively leads to better-quality outcomes, more efficient discharge planning and improved cost-effectiveness of clinical services.