Impact of Mechanical Bowel Preparation on Postoperative Outcomes after Liver Resection for Patients with Hepatocellular Carcinoma: A Single-Center Retrospective Cohort Study

BACKGROUND

Despite the routine use of mechanical bowel preparation (MBP), the real impact of MBP for liver resection remains unclear. The aim of this study was to evaluate the postoperative outcomes of MBP after liver resection for hepatocellular carcinoma (HCC).

METHODS

This was a retrospective cohort study of all patients undergoing liver resection for patients with HCC between from April 2008 to March 2015. MBP was defined as a preoperative medication of polyethylene glycol lavage. We compared perioperative outcomes in patients who did or did not receive MBP before liver resection. Open and laparoscopic hepatectomy were analyzed separately.

RESULTS

A total of 227 patients underwent potentially curative liver resection for HCC during the study period. One hundred twenty-eight patients received MBP while 99 did not. In the open hepatectomy group, overall and major (Clavien-Dindo ≥3) complications were equivalent between the groups (31.9 vs. 25.8%, p = 0.840; 12.1 vs. 8.7%, p = 0.475). There were no meaningful differences in the incidence of liver failure (MBP: 22.4%, non-MBP: 13.0%, p = 0.116). Surgical-site infections occurred in 20 (17.2%) vs. 10 (14.5%) with no significant difference (p = 0.624). Similar results were obtained from the laparoscopic hepatectomy group.

CONCLUSION

The use of MBP does not appear to impact the short outcomes after liver resection for patients with HCC. MBP might be omitted in liver surgery.

von Willebrand Factor-Rich Platelet Thrombi in the Liver Cause Sinusoidal Obstruction Syndrome following Oxaliplatin-Based Chemotherapy

Oxaliplatin-based chemotherapy is widely used to treat advanced colorectal cancer (CRC). Sinusoidal obstruction syndrome (SOS) due to oxaliplatin is a serious type of chemotherapy-associated liver injury (CALI) in CRC patients. SOS is thought to be caused by the sinusoidal endothelial cell damage, which results in the release of unusually-large von Willebrand factor multimers (UL-VWFMs) from endothelial cells. To investigate the pathophysiology of CALI after oxaliplatin-based chemotherapy, we analyzed plasma concentration of von Willebrand factor (VWF) and the distribution of VWFMs in CRC patients. Twenty-three patients with advanced CRC who received oxaliplatin-based chemotherapy with (n = 6) and without (n = 17) bevacizumab were analyzed. CALI (n = 6) and splenomegaly (n = 9) were found only in patients who did not treated with bevacizumab. Plasma VWF antigen (VWF:Ag) and serum aspartate aminotransferase (AST) levels increased after chemotherapy only in patients without bevacizumab. VWFM analysis in patients who did not receive bevacizumab showed the presence of UL-VWFMs and absence of high molecular weight VWFMs during chemotherapy, especially in those with CALI. In addition, plasma VWF:Ag and AST levels increased after chemotherapy in patients with splenomegaly (n = 9), but not in patients without splenomegaly (n = 14). Histological findings in the liver tissue of patients who did not receive bevacizumab included sinusoidal dilatation and microthrombi in the sinusoids. Many microthrombi were positive for both anti-IIb/IIIa and anti-VWF antibodies. Plasma UL-VWFM levels might be increased by damage to endothelial cells as a result of oxaliplatin-based chemotherapy. Bevacizumab could prevent CALI and splenomegaly through inhibition of VWF-rich platelet thrombus formation.

[Long-Term Disease-Free Survival through Postoperative Chemotherapy in a Case of Gastric Cancer with Peritoneal Dissemination]

An 80-year-old man with type 4 gastric cancer in the mid-gastric region underwent total gastrectomy and D2-No.10 lymph-node dissection (cT4a, N0, M0, cStageⅡB). Several nodules were detected under the left diaphragm, some of which were biopsied. Pathological findings indicated a poorly differentiated adenocarcinoma, pT4a (SE), pN3b, pM1 (P1, CY1), pStage Ⅳ. Systemic chemotherapy was initiated, using a regimen of S-1/docetaxel (DOC). After 6 courses of combination therapy, we switched to S-1 alone, which was continued for 1 year. Eighteen months after the surgery the patient discontinued S-1 treatment and has since survived for 5 years with no obvious cancer recurrence.

The impact of intrauterine infection on fetal brain damage assessed by S100B protein concentrations in umbilical cord arteries

OBJECTIVE

To assess the impact of intrauterine infection on fetal brain damage by measuring S100B protein concentration in umbilical cord arteries.

METHODS

In the intrauterine infection cases determined by pathology of 25 deliveries (Group I) and non-infection cases of 35 deliveries as control (Group C), we compared gestational age at delivery, birth weight, fetal heart rate monitoring during labor, Apgar score, umbilical cord artery pH and S100B protein concentrations in umbilical arteries measured by two-site immunoradiometric assay kit.

RESULTS

(1) There was no significant correlation between pH and concentration of S100B protein. (2) Gestational age at delivery was found to be earlier in Group I, resulting in lower birth weights, when compared with Group C. (3) There was no significant difference between two groups concerning Apgar scores, pH. (4) S100B protein concentrations in Group I was significantly higher than those of Group C (3.9 7 ± 0.66 versus 1.8 9 ± 0.56 μg/L, p < 0.05). (5) The concentration of S100B protein in severe chorioamnionitis (CAM) cases were significantly higher than those of mild CAM and control cases.

CONCLUSION

Higher concentration of S100B protein in Group I suggests that intrauterine infection itself has a serious risk factor on fetal brain damage.

Increased tumour ADC value during chemotherapy predicts improved survival in unresectable pancreatic cancer

OBJECTIVES

To investigate whether changes to the apparent diffusion coefficient (ADC) of primary tumour in the early period after starting chemotherapy can predict progression-free survival (PFS) or overall survival (OS) in patients with unresectable pancreatic adenocarcinoma.

METHODS

Subjects comprised 43 patients with histologically confirmed unresectable pancreatic cancer treated with first-line chemotherapy. Minimum ADC values in primary tumour were measured using the selected area ADC (sADC), which excluded cystic and necrotic areas and vessels, and the whole tumour ADC (wADC), which included whole tumour components. Relative changes in ADC were calculated from baseline to 4 weeks after initiation of chemotherapy. Relationships between ADC and both PFS and OS were modelled by Cox proportional hazards regression.

RESULTS

Median PFS and OS were 6.1 and 11.0 months, respectively. In multivariate analysis, sADC change was the strongest predictor of PFS (hazard ratio (HR), 4.5; 95 % confidence interval (CI), 1.7-11.9; p = 0.002). Multivariate Cox regression analysis for OS revealed sADC change and CRP as independent predictive markers, with sADC change as the strongest predictive biomarker (HR, 6.7; 95 % CI, 2.7-16.6; p = 0.001).

CONCLUSION

Relative changes in sADC could provide a useful imaging biomarker to predict PFS and OS with chemotherapy for unresectable pancreatic adenocarcinoma.

KEY POINTS

• Relative change in ADC value can predict survival in unresectable pancreatic cancer. • ADC change could determine a chemosensitivity of pancreatic cancer. • ADC values should be measured by excluding cystic, necrotic areas and vessels.

Huge hepatocellular carcinoma with multiple intrahepatic metastases: An aggressive multimodal treatment

INTRODUCTION

Huge hepatocellular carcinoma (HCC) possesses a potential risk for spontaneous rupture, which leads to a life-threatening complication with a high mortality rate. In addition, a large HCC is frequently accompanied by intrahepatic metastases.

PRESENTATION OF CASE

We describe, the case of a 74-year-old woman with a huge extrahepatically expanding HCC with multiple intrahepatic metastases who was treated by liver resection with repeated transcatheter arterial chemoembolization (TACE). To prevent tumor rupture or bleeding, we performed right hepatectomy. After the operation, TACE was applied for multiple intrahepatic metastases in the remnant liver. Furthermore, the elevated protein induced vitamin K absence (PIVKA II) level had decreased to limits within the normal range. Three months after the first TACE, computed tomography revealed several recurrences in the liver. TACE was applied for the second and third time and the tumors were well controlled.

DISCUSSION

Although, liver resection is occasionally performed for patients with huge HCC to avoid spontaneous tumor rupture, only surgical approach might not be sufficient for such advanced HCC. To achieve long-term survival, it is necessary to control the residual intrahepatic tumors. We could control multiple intrahepatic metastases with repeated TACEs after hepatectomy.

CONCLUSION

Multimodal treatment involving hepatectomy and TACE might be a good treatment strategy for patients with huge HCC with multiple intrahepatic metastases if the tumors are localized in the liver without distant or peritoneal metastasis.

New measurement of antineutrino oscillation with the full detector configuration at Daya Bay

We report a new measurement of electron antineutrino disappearance using the fully constructed Daya Bay Reactor Neutrino Experiment. The final two of eight antineutrino detectors were installed in the summer of 2012. Including the 404 days of data collected from October 2012 to November 2013 resulted in a total exposure of 6.9×10^{5} GW_{th}  ton days, a 3.6 times increase over our previous results. Improvements in energy calibration limited variations between detectors to 0.2%. Removal of six ^{241}Am-^{13}C radioactive calibration sources reduced the background by a factor of 2 for the detectors in the experimental hall furthest from the reactors. Direct prediction of the antineutrino signal in the far detectors based on the measurements in the near detectors explicitly minimized the dependence of the measurement on models of reactor antineutrino emission. The uncertainties in our estimates of sin^{2}2θ_{13} and |Δm_{ee}^{2}| were halved as a result of these improvements. An analysis of the relative antineutrino rates and energy spectra between detectors gave sin^{2}2θ_{13}=0.084±0.005 and |Δm_{ee}^{2}|=(2.42±0.11)×10^{-3}  eV^{2} in the three-neutrino framework.

[A case of idiopathic portal vein obstruction identified by severe bleeding after a routine hemorrhoid operation]

We report our experiences of a case of repeated bleeding after hemorrhoid ligation. A 53-year-old man underwent hemorrhoid ligation for internal hemorrhoids at another hospital. Postoperatively, he developed severe and repeated bleeding. Scanning revealed extrahepatic portal venous obstruction. The severe bleeding persisted after transfer to our institution, where we re-sutured the ligature and performed superior rectal artery embolism, leading to arrest of bleeding. The rectal varix arose due to portal hypertension, which resulted in the diagnosis of idiopathic extrahepatic portal vein obstruction.

Hepatic artery injury during left hepatic trisectionectomy for colorectal liver metastasis treated by portal vein arterialization

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This is a case report of hepatic artery injury during left hepatic trisectionectomy for colorectal liver metastasis treated by portal vein arterialization (PVA).

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Fatal liver failure after hepatectomy was avoided by PVA.

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Subsequential portal hypertension was successfully treated by coil embolization of the PVA.

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PVA seems to be the only way to rescue a patient when hepatic artery reconstruction is impossible, it is important for hepatopancreatobiliary surgeons to know this procedure.

Portal vein arterialization (PVA) has been applied as a salvage procedure in hepatopancreatobiliary surgeries, including transplantation and liver resection, with revascularization for malignancies. Here we describe the use PVA as a salvage procedure following accidental injury of the hepatic artery to the remnant liver occurred during left hepatic trisectionectomy for colorectal liver metastases (CRLM). A 60-year-old man with cancer of the sigmoid colon and initially unresectable CRLM received 11 cycles of hepatic arterial infusion chemotherapy with 5-fluorouracil (1500 mg/week), after which CRLM was downstaged to resectable. One month after laparoscopic sigmoidectomy, a left trisectionectomy and wedge resection of segment 6 were performed. The posterior branch of the right hepatic artery, the only feeding artery to the remnant liver, was injured and totally dissected. Because microsurgical reconstruction of the artery was impossible, PVA was used; PVA is the sole known procedure available when hepatic artery reconstruction is impossible. The patient then suffered portal hypertension, and closure of arterio-portal anastomosis using an interventional technique with angiography was eventually performed on postoperative day 73. Therefore, it is considered that because PVA is associated with severe postoperative portal hypertension, closure of the arterio-portal shunt should be performed as soon as possible on diagnosing portal hypertension.

Relevance of ADAMTS13 to liver transplantation and surgery

A disintegrin-like and metalloproteinase with thrombospondin type-1 motifs 13 (ADAMTS13) specifically cleaves unusually-large von Willebrand factor (VWF) multimers under high shear stress, and down-regulates VWF function to form platelet thrombi. Deficiency of plasma ADAMTS13 activity induces a life-threatening systemic disease, termed thrombotic microangiopathy (TMA) including thrombotic thrombocytopenic purpura (TTP). Children with advanced biliary cirrhosis due to congenital biliary atresia sometimes showed pathological features of TMA, with a concomitant decrease of plasma ADAMTS13 activity. Disappearance of their clinical findings of TTP after successful liver transplantation suggested that the liver is a major organ producing plasma ADAMTS13. In situ hybridization analysis showed that ADAMTS13 was produced by hepatic stellate cells. Subsequently, it was found that ADADTS13 was not merely responsible to development of TMA and TTP, but also related to some kinds of liver dysfunction after liver transplantation. Ischemia-reperfusion injury and acute rejection in liver transplant recipients were often associated with marked decrease of ADAMTS13 and concomitant formation of unusually large VWF multimers without findings of TMA/TTP. The similar phenomenon was observed also in patients who underwent hepatectomy for liver tumors. Imbalance between ADAMTS13 and VWF in the hepatic sinusoid might cause liver damage due to microcirculatory disturbance. It can be called as “local TTP like mechanism” which plays a crucial role in liver dysfunction after liver transplantation and surgery.

A novel measurement method for the morphology of the mandibular ramus using homologous modelling

OBJECTIVES

It is important to assess the mandibular morphology when orthognathic surgery, especially mandibular ramus osteotomy, is performed. Several studies on three-dimensional (3D) facial asymmetry have reported differences in linear and angle measurements between the deviated and contralateral sides in asymmetric mandibles. However, methods used in these studies cannot analyse the 3D morphology of the ramus. In this study, we aimed to evaluate the differences in mandibular ramus between the deviated and contralateral sides in asymmetric mandibles using traditional measurements as well as 3D shape analysis.

METHODS

15 Japanese females with jaw deformities treated by orthodontic surgery were enrolled. 3D CT images were reconstructed, and 14 landmarks were identified on the model surface. Ten linear and four angle measurements were calculated using these landmarks. Homologous ramus models were constructed for each sample, and after converting all homologous models to the right side, 30 homologous models of the ramus were analysed using principal component analysis.

RESULTS

Firstly, eight principal components explained >80% of the total variance. Differences between the deviated and contralateral sides in measurements and scores of the eight principal components were tested. Significant difference at the 5% level between the deviated and contralateral sides was observed in five linear measurements, three angle measurements and the third principal component. The variance of the deviated side was significantly larger in the diameter between the mandibular notch and coronoid process, horizontal dilated angle of the mandibular ramus and vertical dilated angle of the mandibular ramus. The variance of the contralateral side was significantly larger in the height of mandibular ramus, height of posterior of mandibular ramus, condylar width, height of condylar head and mandibular angle. The squared multiple correlation coefficient adjusted for the degrees of freedom was 0.815. The third principal component showed the difference between the deviated and contralateral sides. Shape variation represented by the third principal component visually indicated that the contralateral side was larger and had inwardly directed coronoid process and the deviated side had a mandibular angle that was turned inwards to a greater extent.

CONCLUSIONS

In conclusion, we successfully created a homologous model of the mandibular ramus and demonstrated the effectiveness of this model in the 3D comparison of the ramus morphology between the contralateral and deviated sides in asymmetric mandibles.

Salvage chemoradiotherapy for locally advanced esophageal carcinomas

'Salvage chemoradiotherapy (CRT)' was introduced in 2005 to treat thoracic esophageal carcinomas deemed unresectable based on the intraoperative findings. The therapeutic concept is as follows: the surgical plan is changed to an operation that aims to achieve curability by the subsequent definitive CRT. For this purpose, the invading tumor is resected as much as possible, and systematic lymph node dissection is performed except for in the area around the bilateral recurrent nerves. The definitive CRT should be started as soon as possible and should be performed as planned. We hypothesized that this treatment would be feasible and provide good clinical effects. We herein verified this hypothesis. Twenty-seven patients who received salvage CRT were enrolled in the study, and their clinical course, therapeutic response, and prognosis were evaluated. The patients who had poor oral intake because of esophageal stenosis were able to eat solid food soon after the operation. The radiation field could be narrowed after surgery, and this might have contributed to the high rate of finishing the definitive CRT as planned. As a result, the overall response rate was 74.1%, and 48.1% of the patients had a complete response. No patient experienced fistula formation. The 1-, 3-, and 5-year overall survival rates were 66.5%, 35.2%, and 35.2%, respectively. Salvage CRT had clinical benefits, such as the fact that patients became able to have oral intake, that fistula formation could be prevented, that the adverse events associated with the definitive CRT could be reduced, and that prognosis of the patients was satisfactory. Although the rate of recurrent nerve paralysis was relatively high even after the suspension of aggressive bilateral recurrent nerve lymph node dissection, and the rate of the progressive disease after the definitive CRT was high, salvage CRT appears to provide some advantages for the patients who would otherwise not have other treatment options following a non-curative and residual operation.

Postoperative prognosis of pancreatic cancer with para-aortic lymph node metastasis: a multicenter study on 822 patients

BACKGROUND

The prognosis of pancreatic cancer patients with metastatic para-aortic lymph node (PALN) has been reported to be extremely poor. In general, PALN metastasis has been considered as a contraindication for pancreatic resection. The aim of this study was to reevaluate the postoperative prognostic value of PALN metastasis in pancreatic cancer and to determine the validity of pancreatic surgery.

METHODS

Retrospective multicenter analysis of 882 patients who have undergone curative-intent pancreatic resection with pathological evaluation of PALNs for pancreatic ductal adenocarcinoma between 2001 and 2012 was conducted. Clinicopathological data and outcomes were evaluated with univariate and multivariate analysis.

RESULTS

In total, 102 (12.4 %) patients had positive metastasis in PALN. Patients with metastatic PALN had significantly poorer survival than those without (17 vs. 23 months; p < 0.001). Multivariable analysis of 822 patients identified adjuvant chemotherapy, primary tumor status, regional lymph node metastasis, portal vein invasion, pre- and post-operative serum CA19-9 levels, and tumor grade as independent prognostic factors. In contrast, PALN metastasis did not have a significant prognostic value. Furthermore, the multivariate prognostic analysis in patients with PALN metastasis revealed that adjuvant chemotherapy and the number of metastatic PALN were significantly associated with long-term survival. Lung metastasis as initial recurrence was observed more often in patients with PALN metastasis in comparison with those without.

CONCLUSIONS

Some pancreatic cancer patients with metastatic PALN may survive for longer than expected after pancreatectomy. Adjuvant chemotherapy and the number of metastatic PALN were critical factors for long-term survival of those patients.

Palliative Surgery for Gastric Cancer with Gastric Outlet Obstruction or Anemia due to Tumor Bleeding

BACKGROUND/AIMS

The aim of this study was to evaluate the surgical outcomes after palliative surgery for patients with incurable gastric cancer.

METHODOLOGY

This retrospective study included 45 patients with gastric outlet obstruction (GOO) who needed parental nutrition and 33 patients with anemia due to tumor bleeding who required blood transfusions. We compared the surgical outcomes of palliative gastrectomy (PG) and bypass surgery (BS) in each group.

RESULTS

In the GOO patients, the clinical success rate, as indicated by a resumption of an oral diet, was similar in the PG and BS groups. The time to treatment failure, when the GOO patients again required parental nutrition, was also similar between the two groups. In the anemia patients, the clinical success rate of the PG group was higher than that of BS group, and the post-operative performance status (PS) of the PG group was also better than that of the BS group, although the pre-operative PS were similar in both groups.

CONCLUSIONS

PG for the GOO patients gave little advantage compared to BS, and was associated with a longer operation, higher blood loss and more frequent complications. PG may be recommended for patients with GOO when they simultaneously have anemia due to tumor bleeding.

Clinical significance and therapeutic potential of prostate cancer antigen-1/ALKBH3 in human renal cell carcinoma

Prostate cancer antigen-1 (PCA-1)/ALKBH3 has been recently identified in human prostate cancer and its expression is correlated with disease progression and prognosis. However, the precise role and function of PCA-1/ALKBH3 in human malignancies are largely unknown. In the present study, we investigated the clinical significance and therapeutic potential of PCA-1/ALKBH3 in renal cell carcinoma (RCC). PCA-1/ALKBH3 expression was examined by immunohistochemistry in 101 RCC patients who underwent radical or partial nephrectomy. Its expression was positively correlated with advanced pathological T- and M-factors and TNM stage (T, P<0.05; M, P<0.01; TNM, P<0.01, respectively). In the prognostic analysis, PCA-1/ALKBH3-negative patients with RCC had a significantly better prognosis than PCA-1/ALKBH3-positive patients (5-year survival rate, 92.9 vs. 75.9%, respectively; P<0.05). Next, the therapeutic potential of targeting PCA-1/ALKBH3 was further evaluated by small interfering RNA method using a human RCC cell line (CAKI-1). We found that PCA-1/ALKBH3 knockdown significantly inhibited the growth of CAKI-1 cells compared with the control (P<0.001). Furthermore, knockdown of PCA-1 induced apoptosis in CAKI-1 cells, as assessed by poly(ADP-ribose) polymerase-cleavage assays. We demonstrated for the first time that PCA-1/ALKBH3 expression has a significant prognostic impact on patient prognosis in RCC. Furthermore, its knockdown has a therapeutic efficacy on RCC. Taken together, both our clinical and experimental data strongly suggest that PCA-1/ALKBH3 may be functionally important and a novel molecular target for human RCC.

Eosinophilic cholangitis coexisted with idiopathic thrombocytopenic purpura: Report of a case

Eosinophilic cholangitis is a rare disease of which only 31 cases have been reported. Eosinophilic infiltration causes stricture of the bile duct diffusely or locally, and the imaging of eosinophilic cholangitis resembles primary sclerosing cholangitis or cancer of the bile tract. For eosinophilic cholangitis, treatment with steroid is effective and the prognosis is good. Therefore, its accurate diagnosis is very important. Here, we describe a patient with eosinophilic cholangitis who was also diagnosed with idiopathic thrombocytopenic purpura (ITP). He was treated for ITP using prednisolone, the unexpected sudden interruption of which caused severe deterioration of eosinophilic cholangitis and acute cholecystitis. Cholecystectomy and choledochojejunostomy were performed, and the addition of treatment by prednisolone resulted in a good clinical course. This is the first report on eosinophilic cholangitis coexisting with ITP.

Importance of resectability status in neoadjuvant treatment for pancreatic cancer

BACKGROUND

Much attention has been paid to neoadjuvant treatment (NAT) as a new strategy especially for borderline resectable pancreatic cancer (BRPC). However, the optimal indication of NAT remains undetermined.

METHODS

We analyzed 248 patients with pancreatic cancer (PC). One hundred resectable tumors were classified as R group. Sixty-nine tumors with venous involvement were classified as BR-P group, while 31 tumors with arterial involvement were classified as BR-A group. Ninety-nine patients received NAT. Furthermore, 48 unresectable locally advanced PC served as controls (LAPC group). Among them, 11 patients received adjuvant surgery afterwards (Ad-surg group).

RESULTS

The overall median survival time in the R, BR-P and BR-A groups was 45.3, 24.8 and 16.8 months. In the R and BR-P groups, patients treated with NAT had a better prognosis than those without. In contrast, NAT had no impact on prognosis in the BR-A group. Patients treated with NAT in the BR-P, but not BR-A group, had a better prognosis than patients in the LAPC group. Furthermore, patients in the Ad-surg group had a significantly better prognosis than patients in the BR-A group.

CONCLUSIONS

Borderline resectable pancreatic cancer with venous involvement, but without arterial involvement, may be a good indication for NAT. Our data highlight the importance of preoperative resectability assessment to evaluate the indication and efficacy of NAT.

Learning curve for laparoscopic major hepatectomy

BACKGROUND

Laparoscopic major hepatectomy (LMH) is evolving as an important surgical approach in hepatopancreatobiliary surgery. The present study aimed to evaluate the learning curve for LMH at a single centre.

METHODS

Data for all patients undergoing LMH between January 1998 and September 2013 were recorded in a prospective database and analysed. The learning curve for operating time (OT) was evaluated using the cumulative sum (CUSUM) method.

RESULTS

Of 173 patients undergoing major hepatectomy, left hepatectomy was performed in 28 (16·2 per cent), left trisectionectomy in nine (5·2 per cent), right hepatectomy in 115 (66·5 per cent), right trisectionectomy in 13 (7·5 per cent) and central hepatectomy in eight (4·6 per cent). Median duration of surgery was 270 (range 100-540) min and median blood loss was 300 (10-4500) ml. There were 20 conversions to an open procedure (11·6 per cent). Vascular clamping was independently associated with conversion on multivariable analysis (hazard ratio 5·95, 95 per cent c.i. 1·24 to 28·56; P = 0·026). The CUSUMOT learning curve was modelled as a parabola (CUSUMOT  = 0·2149 × patient number(2)  - 30·586 × patient number - 1118·3; R(2)  = 0·7356). The learning curve comprised three phases: phase 1 (45 initial patients), phase 2 (30 intermediate patients) and phase 3 (the subsequent 98 patients). Although right hepatectomy was most common in phase 1, a significant decrease was observed from phase 1 to 3 (P = 0·007) in favour of more complex procedures.

CONCLUSION

The learning curve for LMH consisted of three characteristic phases identified by CUSUM analysis. The data suggest that the learning phase of LMH included 45 to 75 patients.