Kiichiro Kobayashi

Cyst size indicates malignant transformation in branch duct intraductal papillary mucinous neoplasm of the pancreas without mural nodules.

Objectives: In branch duct intraductal papillary mucinous neoplasm (IPMN) of the pancreas, the importance of the cyst size to predict malignancy is still controversial. Our aim was to elucidate the malignant potential of branch duct IPMN without mural nodules (flat branch duct IPMN). Methods: Seventy-three patients with flat branch duct IPMNs were studied in our institution. Results: There were 6 malignant IPMNs in this series, all of which were 30 mm or more in size, whereas there was no malignancy in IPMNs of less than 30 mm. Statistically significant predictors of malignancy were atypical cytological condition and main pancreatic duct (MPD) diameter of 5 mm or more. The cyst size of 30 mm or more tended to be associated with malignancy. The frequency of malignancy in flat branch duct IPMNs with the size of 30 mm or more and MPD diameter of less than 5 mm was 3.6%, whereas there were 5 malignant cases (26.3%) in flat branch duct IPMNs with the size of 30 mm or more and MPD diameter of 5 mm or more. Conclusions: We conclude that the size criteria (≥30 mm) to predict malignancy proposed in the international consensus guidelines is appropriate and resection or meticulous follow-up using cytological examination and MPD dilatation is needed in patients with flat branch duct IPMNs.

Clinical aspects of intraductal papillary mucinous neoplasm of the pancreas.

Intraductal papillary mucinous neoplasm (IPMN) is a spectrum of neoplasia in the pancreatic duct epithelium characterized by cystic dilation of the main and/or branch pancreatic duct. According to the site of involvement IPMNs are classified into three categories, i.e., main duct type, branch duct type, and combined type. Most branch duct IPMNs are benign, whereas the other two types are often malignant. A large size of branch duct IPMN and marked dilation of the main pancreatic duct indicate the presence of adenoma at least. The additional existence of large mural nodules increases the possibility of malignancy in all types. Of recent interest is the relatively high prevalence of synchronous and/or metachronous malignancy in various organs, including the pancreas. The prognosis is favorable after complete resection of benign and noninvasive malignant IPMNs. Malignant IPMNs acquiring aggressiveness after parenchymal invasion necessitate adequate lymph node dissection. On the other hand, asymptomatic branch duct IPMNs without mural nodules can be observed without resection for a considerably long time. This review addresses available data, current understanding, controversy, and future directions.

Construct validity for eye-hand coordination skill on a virtual reality laparoscopic surgical simulator.

BackgroundThis study was carried out to investigate whether eye-hand coordination skill on a virtual reality laparoscopic surgical simulator (the LAP Mentor) was able to differentiate among subjects with different laparoscopic experience and thus confirm its construct validity.MethodsA total of 31 surgeons, who were all right-handed, were divided into the following two groups according to their experience as an operator in laparoscopic surgery: experienced surgeons (more than 50 laparoscopic procedures) and novice surgeons (fewer than 10 laparoscopic procedures). The subjects were tested using the eye-hand coordination task of the LAP Mentor, and performance was compared between the two groups. Assessment of the laparoscopic skills was based on parameters measured by the simulator.ResultsThe experienced surgeons completed the task significantly faster than the novice surgeons. The experienced surgeons also achieved a lower number of movements (NOM), better economy of movement (EOM) and faster average speed of the left instrument than the novice surgeons, whereas there were no significant differences between the two groups for the NOM, EOM and average speed of the right instrument.ConclusionsEye-hand coordination skill of the nondominant hand, but not the dominant hand, measured using the LAP Mentor was able to differentiate between subjects with different laparoscopic experience. This study also provides evidence of construct validity for eye-hand coordination skill on the LAP Mentor.

Appleby Operation for Pancreatic Body-Tail Carcinoma: Report of Three Cases

The clinical course of patients with carcinoma of the pancreas, especially of the body-tail, remains dismal despite recent advances in diagnostic and therapeutic procedures. We present three case reports to evaluate the role of the Appleby operation in the treatment of pancreatic body-tail cancer. Care 1 was a 55-year-old Japanese woman who underwent the Appleby operation for mucinous cystadenocarcinoma of the body and tail of the pancreas invading the stomach, celiac axis, superior mesenteric and splenic arteries, and the splenic, superior mesenteric, and portal veins. Local recurrence and peritoneal dissemination with malignant ascites were found 7 months later and she died 10 months after the operation. Case 2 was a 61-year-old Japanese man who underwent the Appleby operation with 20 Gy radiation therapy for invasive ductal carcinoma of the body of the pancreas involving the celiac axis, common hepatic, splenic, and left gastric arteries, and the splenic vein. Peritoneal dissemination with malignant ascites was evident 5 months later and he died 14 months after the operation. Case 3 was a 50-year-old Japanese man who underwent the Appleby operation with 20 Gy radiation therapy for invasive ductal carcinoma of the body of the pancreas invading the stomach, splenic artery, celiac axis, and splenic vein. Multiple hepatic metastases were found 2 months later and the patient died 8 months after the operation. Based on our experience of these three cases, we conclude that the indications for the Appleby operation to treat locally advanced pancreatic body carcinoma are still limited because it does not improve quality of life or clinical outcome.

Factors in intraductal papillary mucinous neoplasms of the pancreas predictive of lymph node metastasis

Background: Little is known about the frequency of lymph node metastasis (LNM) in intraductal papillary mucinous neoplasms (IPMNs), and we have not been able to determine how much lymph node dissection is necessary in individual cases. The aim of this study was to investigate the predictive factors for the LNM in IPMNs. Methods: Medical records of 120 patients pathologically diagnosed as having IPMN were reviewed, and 16 possible predictive factors regarding the LNM were analyzed. Results: LNM was observed in 7 patients (6%), all of whom were diagnosed as having mural nodules preoperatively. Sensitivity, specificity, and accuracy of preoperative imaging for detecting mural nodules of IPMNs in this study were 84, 97, and 90%, respectively. Univariate analysis using 61 patients having mural nodules preoperatively revealed that the size of mural nodules ≧10 mm and positive imaging findings for invasive tumor and possible LNM were significant predictive factors for the LNM. Multivariate analysis demonstrated that only an imaging finding for invasive tumor was an independent significant predictive factor. Positive and negative predictive values of the imaging finding of invasive IPMNs for LNM were 50 and 98%, respectively. Conclusions: Standard lymph node dissection would be recommended in patients with IPMNs with mural nodules demonstrating preoperative imaging findings for invasive carcinomas.

Duodenum is important for the sphincter of Oddi motor response to cholecystokinin octapeptide in conscious dogs

BackgroundWe investigated the role of the duodenum in the sphincter of Oddi response to cholecystokinin-octapeptide (CCK-OP), using conscious dogs.MethodsIn controls, a cannula was inserted into the duodenum opposite the papilla for retrograde manometry. In the duodenectomy group, the entire duodenum was resected, while preserving the papilla, which was implanted into the jejunum, and the cannula was placed. Sphincter motility was recorded after bolus injections of 20 and 100 ng/kg of CCK-OP.ResultsCCK-OP at 20 ng/kg produced sphincter relaxation followed by contraction in the controls, but produced no changes after duodenectomy. CCK-OP at 100 ng/kg caused strong contractions followed by relaxation in the controls, but caused only contractions after duodenectomy.Conclusions(1) Relaxation and delayed contraction of the sphincter induced by 20 ng/kg of CCK-OP require the presence of the duodenum; (2) early contractions of the sphincter induced by 100 ng/kg of CCK-OP do not require the duodenum; (3) the duodenum plays an important role in the actions of CCK-OP on sphincter motility.

Role of Duodenum on Sphincter of Oddi Motility in Conscious Dogs

Our aim was to determine the role of the duodenum in controlling sphincter of Oddi motility using conscious dogs after total duodenectomy. In a control group (N = 6), a cannula was implanted into the duodenum opposite to the papilla to allow retrograde sphincter manometry. In a duodenectomy group (N = 6), the papillae were preserved at total duodenectomy and sutured to the jejunum anastomosed to the stomach (neoduodenum). The cannula was implanted opposite to the implanted papillae. Interdigestive and postprandial sphincter and duodental or neoduodenal motility were recorded by manometric and myoelectric methods. Duodenectomy disrupted sphincter cyclic motility associated with the intestinal migrating motor complex and increased sphincter activity throughout the cycle. Sphincter activity increased immediately after feeding and did not differ between the two groups. In conclusion, during the interdigestive period, the duodenum has a distinct role in regulating sphincter cyclic motility. The initiation of the fed pattern of sphincter motility does not need the duodenum.