Designing a synthetic simulator to teach open surgical skills for limb exploration in trauma: a qualitative study exploring the experiences and perspectives of educators and surgical trainees

Background

Simulation is an important adjunct to aid in the acquisition of surgical skills of surgical trainees. The simulators used to adequately enable trainees to learn, practice and be assessed in surgical skills need to be of the highest standards. This study investigates the perceived requirements of simulation and simulators used to acquire skills in limb exploratory procedures in trauma.

Methods

Semi-structured interviews were conducted with an international group of 11 surgical educators and 11 surgical trainees who had experience with surgical simulation. The interviews focused on the perceptions of simulation, the integration of simulators within a curriculum and the features of a simulator itself. Interviews were recorded, transcribed and underwent thematic analysis.

Results

Analysis of the perspectives of surgical educators and surgical trainees on simulated training in limb trauma surgery yielded three main themes: (1) Attitudes to simulation. (2) Implementing simulation. (3) Features of an open skills simulator. The majority felt simulation was relevant, intuitive and a good way for procedure warmup and the supplementation of surgical logbooks. They felt simulation could be improved with increased accessibility and variety of simulator options tailored to the learner. Suggested simulator features included greater fidelity, haptic feedback and more complex inbuilt scenarios. On a practical level, there was a desire for cost effectiveness, easy set up and storage. The responses of the educators and the trainees were similar and reflected similar concerns and suggestions for improvement.

Conclusion

There is a clear positive appetite for the incorporation of simulation into limb trauma training. The findings of this will inform the optimal requirements for high quality implementation of simulation into a surgical trauma curriculum and a reference to optimal features desired in simulator or task trainer design.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12893-021-01417-7.

Use of powered air-purifying respirators during surgical interventions

This clinical study confirms user acceptability of PAPR during surgery both at operating room team level as well as by groups of surgeons, anaesthesiologists and nursing level. While some care is needed in the use of this equipment, surgery can be performed safely with satisfactory user experience.

Therefore PAPR is useable for surgery but scope exists for improvement.

Iatrogenic common bile duct injuries: Increasing complexity in the laparoscopic era: A prospective cohort study

PURPOSE

Iatrogenic bile duct injury (BDI) is the most significant associated complication to laparoscopic cholecystectomy (LC). Little is known about the evolution of the pattern of BDI in the era of laparoscopy. The aim of the study is to assess the pattern of post-LC BDIs managed in a tertiary referral centre.

METHODS

Post-LC BDI referred over two decades were studied. Demographic data, type of BDI (classified using the Strasberg System), clinical symptoms, diagnostic investigations, timing of referral, post-referral management and morbidity were analysed. The pattern of injury, associated vascular injuries rate and their management were compared over two time periods (1992-2004,2005-2014).

RESULTS

78 BDIs were referred. During the second time period Strasberg A injuries decreased from 14% to 0 and Strasberg E1increased from 4% to 23%, the rate of associated vascular injury was six time higher (3.6% versus 22.7%), more patients had an attempted repair at the index hospital (16% versus 35%) sand fewer patients could be managed without surgical intervention at the referral hospital (28% versus 4%).

CONCLUSION

Complexity of referred BDIs and rate of associated vascular injuries have increased over time. These findings led to more patients managed requiring surgical intervention at the referral hospital.

Pancreatic metastasectomy: experience of the Irish National Surgical Centre for Pancreatic Cancer

BACKGROUND

Metastatic tumours of the pancreas are rare and the optimal management of these tumours remains unclear, given the paucity of data existing in the literature. We report our experience of pancreatic metastasectomy.

METHODS

Data were reviewed on all patients who underwent pancreatic resection for pathologically confirmed metastatic lesions over a consecutive 7-year period.

RESULTS

Seven patients (two men and five women) underwent a pancreatectomy for a metastatic pancreatic tumour. The primary tumours were renal cell carcinoma (n = 3), colorectal carcinoma (n = 2) and leiomyosarcoma (n = 2). There was no operative mortality. Postoperative morbidities occurred in two patients. The median follow-up was 49 months (range 17-76). Overall 1- and 2-year survivals were 100 and 86 %, respectively, with a 2-year disease-free survival of 72 %.

CONCLUSIONS

Our series further supports that pancreatic metastasectomy can be performed safely and achieves acceptable survival outcomes.

Pancreatectomy for metastatic disease: a systematic review

AIM

Tumours rarely metastasise to the pancreas. While surgical resection of such metastases is believed to confer a survival benefit, there is limited data to support such management. We present a systematic review of case series of pancreatic metastasectomy and analysis of survival outcomes.

METHODS

A literature search was performed using the PubMed and Cochrane databases and the reference lists of relevant articles, searching for sizeable case series of pancreatic metastasectomy with curative intent. Data extracted included basic demographics, histological primary tumour, presentation, operative management, complications and survival, while the MINORS index was used to assess study quality.

RESULTS

18 studies were found which met our inclusion criteria, involving 399 patients. Renal cell carcinoma (RCC) was the commonest malignancy metastasising to the pancreas, responsible for 62.6% of cases, followed by sarcoma (7.2%) and colorectal carcinoma (6.2%). While survival data was not uniformly reported, the median survival post-metastasectomy was 50.2 months, with a one-year survival of 86.81% and five-year survival of 50.02%. Median survival for RCC was 71.7 months with 70.4% five-year survival. Median survival was similar in patients with synchronous and metachronous pancreatic metastases, but patients with additional extrapancreatic metastases had a significantly shorter survival than patients with isolated pancreatic metastases (26 versus 45 months). Study quality was poor, with a median MINORS score of 10/16.

CONCLUSIONS

Within the limitations of a review of non-randomised case series, it would appear that pancreatic metastasectomy confers a survival benefit in selected patients. Better evidence is required, but may prove difficult to acquire.

Higher surgical training opportunities in the general hospital setting; getting the balance right

BACKGROUND

The general hospital can play an important role in training of higher surgical trainees (HSTs) in Ireland and abroad. Training opportunities in such a setting have not been closely analysed to date.

AIMS

The aim of this study was to quantify operative exposure for HSTs over a 5-year period in a single institution.

METHODS

Analysis of electronic training logbooks (over a 5-year period, 2007-2012) was performed for general surgery trainees on the higher surgical training programme in Ireland. The most commonly performed adult and paediatric procedures per trainee, per year were analysed.

RESULTS

Standard general surgery operations such as herniae (average 58, range 32-86) and cholecystectomy (average 60, range 49-72) ranked highly in each logbook. The most frequently performed emergency operations were appendicectomy (average 45, range 33-53) and laparotomy for acute abdomen (average 48, range 10-79). Paediatric surgical experience included appendicectomy, circumcision, orchidopexy and hernia/hydrocoele repair. Overall, the procedure most commonly performed in the adult setting was endoscopy, with each trainee recording an average of 116 (range 98-132) oesophagogastroduodenoscopies and 284 (range 227-354) colonoscopies.

CONCLUSIONS

General hospitals continue to play a major role in the training of higher surgical trainees. Analysis of the electronic logbooks over a 5-year period reveals the high volume of procedures available to trainees in a non-specialist centre. Such training opportunities are invaluable in the context of changing work practices and limited resources.

Hyaline vascular Castleman's disease involving the biliary tract

We report a case of Castleman's Disease (CD), hyaline vascular subtype involving the biliary tract with obstruction. A 43 year old man presented with a 5 week history of abdominal and back pain with biliary obstructive symptoms. He was jaundiced with persistently high LFTs. Radiological investigation revealed a stricture in the extrahepatic biliary tract. The clinical impression at the time was of sclerosing cholangitis with bile duct cholangiocarcinoma. A Whipple's procedure was performed. Histology and immunohistochemistry supported the histologic diagnosis of CD of hyaline vascular subtype. There was no evidence of disease elsewhere and the patient was disease free after a 6 year follow-up. Our case describes the hyaline vascular subtype of CD, a relatively rare disease occurring in a previously undescribed location.

Bench and bedside? Surgeons' views on the role of research in surgical training

AIMS

Internationally, surgical training is facing the challenge of balancing research and clinical experience in the context of reduced working hours. This study aimed to investigate trainees and trainers' views on surgeons participating in full-time research during surgical training.

METHODS

An anonymous voluntary survey was conducted of surgical trainers and trainees in two training systems. To examine surgeons' views across two different training schemes, surgeons were surveyed in Ireland (Royal College of Surgeons in Ireland) and in a Canadian centre (University of Toronto) between January 2009 and September 2010 (n = 397 respondents).

RESULTS

The majority of respondents felt that time spent in research by trainees was important for surgery as a specialty, while 65 % felt that research was important for surgical trainees (trainers 79 %, trainees 60 %, p = 0.001). A higher proportion of Canadian surgeons reported that they enjoyed their time spent in research, compared to Irish surgeons (84 vs. 66 %, p = 0.05). Financial worries and loss of clinical time were common demotivating factors. Full-time research was more popular than part-time options to obtain a post-graduate degree.

CONCLUSIONS

Most agree that research remains an important component of surgical training. However, there are significant differences in opinion among surgeons in different countries on the precise role and structure of research in surgical training.

Towards continuous improvement of endoscopy standards: validation of a colonoscopy assessment form

AIM

The assessment of procedural colonoscopy skills is important and topical. The aim of this study was to develop and validate a competency-based colonoscopy assessment form that would be easy to use, suitable for the assessment of junior and senior endoscopists and potentially a useful instrument to detect differences in performance standards following different training interventions.

METHOD

A standardized assessment form was developed incorporating a checklist with dichotomous yes/no responses and a global assessment section incorporating several different elements. This form was used prospectively to evaluate colonoscopy cases during the period of the study in several university teaching hospitals. Results were analysed using ANOVA with Bonferroni corrections for post hoc analysis.

RESULTS

Eighty-one procedures were assessed, performed by eight consultant and 19 trainee endoscopists. There were no serious errors. When divided into three groups based on previous experience (novice, intermediate and expert) the assessment form demonstrated statistically significant differences between all three groups (P<0.05). When separate elements were taken into account, the global assessment section was a better discriminator of skill level than the checklist.

CONCLUSION

This form is a valid, easy-to-use assessment method. We intend to use it to assess the value of simulator training in trainee endoscopists. It also has the potential to be a useful training tool when feedback is given to the trainee.

Video gaming enhances psychomotor skills but not visuospatial and perceptual abilities in surgical trainees

INTRODUCTION

There is considerable interest in the identification and assessment of underlying aptitudes or innate abilities that could potentially predict excellence in the technical aspects of operating. However, before the assessment of innate abilities is introduced for high-stakes assessment (such as competitive selection into surgical training programs), it is essential to determine that these abilities are stable and unchanging and are not influenced by other factors, such as the use of video games. The aim of this study was to investigate whether experience playing video games will predict psychomotor performance on a laparoscopic simulator or scores on tests of visuospatial and perceptual abilities, and to examine the correlation, if any, between these innate abilities.

METHODS

Institutional ethical approval was obtained. Thirty-eight undergraduate medical students with no previous surgical experience were recruited. All participants completed a self-reported questionnaire that asked them to detail their video game experience. They then underwent assessment of their psychomotor, visuospatial, and perceptual abilities using previously validated tests. The results were analyzed using independent samples t tests to compare means and linear regression curves for subsequent analysis.

RESULTS

Students who played video games for at least 7 hours per week demonstrated significantly better psychomotor skills than students who did not play video games regularly. However, there was no difference on measures of visuospatial and perceptual abilities. There was no correlation between psychomotor tests and visuospatial or perceptual tests.

CONCLUSIONS

Regular video gaming correlates positively with psychomotor ability, but it does not seem to influence visuospatial or perceptual ability. This study suggests that video game experience might be beneficial to a future career in surgery. It also suggests that relevant surgical skills may be gained usefully outside the operating room in activities that are not related to surgery.

Inflammatory pseudotumours of the liver--role of dynamic MRI scan and surgical exploration

Inflammatory pseudotumours of the liver are extremely rare benign lesions. They were first described by Pack and Baker in 1953. They usually present with raised inflammatory markers and nonspecific abdominal symptoms. Most of these lesions are picked up incidentally on ultrasound scans. Diagnosis of these lesions poses a dilemma and a challenge due to their radiological similarities to other liver lesions such as hepatocellular carcinoma HCC. In this article we describe our experience in its diagnosis and management.

Coping with stress in surgery: the difficulty of measuring non-technical skills

BACKGROUND

Non-technical skills are relevant to surgical performance but are difficult to quantify. The aim of this study was to investigate the relationship between self-efficacy, which is a measure of stress-coping ability, and surgical performance.

METHODS

Two hundred and sixteen basic surgical trainees were assessed on their performance of three bench model-type open and laparoscopic surgical tasks. They also completed a 10-item General Self-Efficacy (GSE) questionnaire to assess their stress-coping abilities. Their assessment scores were correlated with the GSE scores.

RESULTS

The mean GSE score of 31.39 was higher than the recorded population norms. There was no significant correlation between GSE and surgical performance for open or laparoscopic tasks.

CONCLUSION

Junior surgical trainees have high self-belief scores, but these abilities are difficult to measure and quantify. More refined methods may be necessary to measure non-technical skills relevant to surgery.

Radical pancreaticoduodenectomy for benign disease

Whipple's procedure is the treatment of choice for pancreatic and periampullary malignancies. Preoperative histological confirmation of malignancy is frequently unavailable and some patients will subsequently be found to have benign disease. Here, we review our experience with Whipple's procedure for patients ultimately proven to have benign disease. The medical records of all patients who underwent Whipple's procedure during a 15-year period (1987–2002) were reviewed; 112 patients underwent the procedure for suspected malignancy. In eight cases, the final histology was benign (7.1%). One additional patient was known to have benign disease at resection. The mean age was 50 years (range: 30–75). The major presenting features included jaundice (five), pain (two), gastric outlet obstruction (one), and recurrent gastrointestinal haemorrhage (one). Investigations included ultrasound (eight), computerised tomography (eight), endoscopic retrograde cholangiopancreatography (seven; of these, four patients had a stent inserted and three patients had sampling for cytology), and endoscopic ultrasound (two). The pathological diagnosis included benign biliary stricture (two), chronic pancreatitis (two), choledochal cyst (one), inflammatory pseudotumour (one), cystic duodenal wall dysplasia (one), duodenal angiodysplasia (one), and granular cell neoplasm (one). There was no operative mortality. Morbidity included intra-abdominal collection (one), anastomotic leak (one), liver abscess (one), and myocardial infarction (one). All patients remain alive and well at mean follow-up of 41 months. Despite recent advances in diagnostic imaging, 8% of the patients undergoing Whipple's procedure had benign disease. A range of unusual pathological entities can mimic malignancy. Accurate preoperative histological diagnosis may have allowed a less radical operation to be performed. Endoscopic ultrasound–guided fine needle aspirate (EUS-FNA) may reduce the need for Whipple's operation in benign pancreaticobiliary disease in the future.

Significant influence of the primary liver disease on the outcomes of hepatic retransplantation

BACKGROUND

There are many indications for hepatic retransplantation.

AIM

To identify factors influencing retransplantation needs and outcomes.

PATIENTS AND METHODS

Retransplantation records from January 1993 to March 2005 were analysed. Patient and disease characteristics and survival outcomes for retransplantation were compared between various groups.

RESULTS

Totally, 286 primary and 42 hepatic retransplantations were performed. Retransplantation indications included primary sclerosing cholangitis (PSC), primary biliary cirrhosis, chronic hepatitis C (HCV), chronic active hepatitis (CAH), and alcohol-related disease. Mean follow-up post-retransplantation was 31 +/- 9 months. Actuarial patient survival at 3 months, 1 year, 3 years, 5 years, and at the end of study was 71.4, 69, 59.5, 54.7, and 50%, respectively. Early and late retransplantation had 1-year survival of 73 and 68.5%, respectively. Retransplantation need was significantly higher for PSC, HCV, and CAH.

CONCLUSIONS

Hepatic retransplantation remains a successful salvage option for transplant complications; however, its need is significantly influenced by the primary liver disease.

The "flying" bile duct: avulsion of the common bile duct in a plane crash survivor

Blunt trauma is an unusual cause of extrahepatic bile duct injury. This is a case of a 51-year-old gentleman who sustained a significant seatbelt injury in a plane crash. Laparotomy, performed due to persistent abdominal pain, revealed that the common bile duct (CBD) was completely avulsed from the duodenum. Following insertion of drains and transfer to a hepatobiliary centre, the devascularised CBD was excised and replaced with a roux-en-y hepaticojejunostomy. Necrotic tissue was debrided from the pancreatic head. A persistent bile leak developed from the sub-hepatic drain. Repeat laparotomy revealed a bile leak from small ducts on the liver surface. Ligation of the ducts and bioglue sealing of the area were successfully performed. Subsequent to this a pancreatic fistula developed from the main pancreatic duct, which has since resolved. This unusual case illustrates the need for prompt recognition and early repair to optimise outcomes in traumatic CBD injury.

Potential impact of text message reminders on non-attendance at outpatient clinics

BACKGROUND

Non-attendance at outpatient clinic leads to significant time wasting and inefficient use of resources.

AIMS

To establish the magnitude of the problem of clinic non-attendance and to ascertain the potential impact of a simple strategy to reduce inefficiency in Irish healthcare.

METHODS

The number of patients due to attend general surgical clinic in a single year was ascertained. Telephone questionnaire of 97 patients who failed to attend was performed. A survey of potential impact of text message reminder was conducted.

RESULTS

Appointments were sent to 18,362 patients. Of these, 31% (n = 5692) were new to clinic. The rate of non-attendance was 16.8% (n = 3085). Varied reasons were given for non-attendance. Text message reminder would encourage 51% of those surveyed to attend or cancel in advance.

CONCLUSION

The rate of non-attendance is 17%. A reminder would eradicate more than half of non-attendance, allowing significantly more new patients to be seen, translating to more efficient use of clinic time.

Improved survival outcomes for liver transplantation

Liver transplantation is the treatment of choice for end stage liver disease and fulminant hepatic failure. Outcome of the procedure may be dependent on multiple factors including patient selection, donor selection, and centre experience.

AIM

To determine whether the outcome for liver transplantation has improved over the time for the Irish National Liver Transplant Unit since its initial set up in 1993.

METHODS

All patients who underwent liver transplantation between Jan 1993 to Oct 2004 were included. Patients were sub-divided into three sequential cohorts of 90 patients each. Survival outcomes were compared between the groups.

RESULTS

270 patients (male = 137) underwent 323 liver transplants (median age 49 yrs, range 16-68 yrs). Indications included primary biliary cirrhosis (14.1%), alcohol related liver disease (6.2%), fulminant hepatic failure (14.2%), primary sclerosing cholangitis (10.1%), chronic active hepatitis (9.5%), viral hepatitis (9.5%) and cryptogenic cirrhosis (7.1%). Most procedures (85.8%) were elective. Re-transplantation rates within the first 3 months of primary procedure were 9%, 5%, and 5% for the three chronological groups. Overall calculated 3-month, 1-year and 3 year survival rates for group 1 were 87%, 82% and 77%. For the groups 2 and 3 the figures were 86%, 81%, 77% and 89%, 89%, and 81% respectively. One- and 3-year survival rates were significantly better for group 3 compared to group 1 (p < 0.05).

CONCLUSIONS

Survival outcome has improved significantly over the past 12 years and is likely attributed to increasing experience of the transplant centre.

MELD score as a prognostic model for listing acute liver failure patients for liver transplantation

OBJECTIVES

The King's College Hospital (KCH) criteria are widely used for listing patients with acute liver failure (ALF) for liver transplantation (LT). Recent reports have suggested that the Model for End-Stage Liver Disease (MELD) score may be useful in assessing prognosis in ALF (nonparacetamol). This study compares prognostic accuracy of the two systems in patients with paracetamol (POD)-induced ALF treated in this unit.

METHODS

Seventy-two patients (average age 38 years; F:M ratio 2:1) admitted from 1994 to 2005 with POD-related ALF were studied. Clinical and biochemical parameters were recorded. The effect of applying a MELD score of greater than 30 as listing criteria for LT was calculated and compared with the KCH criteria. Outcomes were defined as LT, death, or full recovery.

RESULTS

Thirty-one patients (43%) recovered with medical therapy, 29 (40%) patients died, and 12 (17%) underwent LT. Sixty five percent of patients had a MELD > 30 and therefore could potentially be listed on admission; however, using KCH criteria only 24% patients were listed immediately. Sensitivity and negative predictive value of MELD was higher then KCH; however, we found KCH to have much higher specificity and positive predictive value.

CONCLUSION

MELD has higher sensitivity and negative predictive value for POD-induced ALF than the KCH criteria. However, the high false-positive rate associated with MELD limits its clinical utility. The high negative predictive value of MELD score may allow it to be used in conjunction with KCH criteria to avoid unneeded LT in patients who will likely recover spontaneously.

Hepatic interleuklin 15 (IL-15) expression: implications for local NK/NKT cell homeostasis and development

Interleukin 15 (IL-15) is critical for the development of human and murine natural killer (NK) cells and hepatic-derived NK T cells (NKT) in mice, and for the homeostatic maintenance of NK/NKT and CD8(+) memory T cells. The lymphocyte repertoire of an adult human liver includes significant populations of NK and NKT-like cells, which may arise locally from hepatic haematopoietic stem cells (HSCs). We investigated hepatic IL-15 levels and the expression of IL-2/IL-15-receptor beta-chain (IL-2/IL-15Rbeta; CD122) on mature hepatic lymphocytes and HSCs. Reverse transcription-polymerase chain reaction (RT-PCR) was used to detect secreted/intracellular IL-15 transcripts. IL-15 protein was localized using immunohistochemistry; levels were measured by enzyme-linked immunosorbent assay IL-2/IL-15Rbeta expression by flow-cytometry. Normal hepatic IL-15 protein was detected at 0.43 ng/100 mg total protein (n = 11, range 0.10 ng-0.9 ng). There was a significant increase in HCV-infected tissue (1.78 ng, P < 0.005, n = 11, range 0.18-2.43 ng). The staining pattern suggests that infiltrating monocytes and tissue resident Kupffer cells are the main producers. IL-15 protein was detected in supernatants from cultured liver biopsy specimens in the absence of stimulation (mean 175.8 pg/100 mg wet tissue, n = 3), which increased significantly upon stimulation (P < 0.05, mean 231.21 pg). On average, 61% of hepatic HSCs expressed IL-2/IL-15Rbeta suggesting a local lymphopoietic role. Eighty per cent of NK and 45.8% of CD56(+) T cells expressed IL-2/IL-15Rbeta, suggesting involvement in local CD56(+) cell activation and expansion. Constitutive expression of IL-15 protein and IL-2/IL-15Rbeta on hepatic lymphocytes suggests a key role in the generation and maintenance of the unique hepatic lymphoid repertoire. The significant increase observed in HCV-infected liver suggests a role for IL-15 in host antiviral responses in the liver.

Spontaneous hepatic rupture: a report of five cases

BACKGROUND

Spontaneous hepatic rupture is a well recognised but rare condition. Because of the difficulty in diagnosis, it is often associated with a high mortality rate. Pregnant women with HELLP syndrome are more prone to hepatic rupture, but it can also occur with other liver pathology. Different modalities of treatment, including liver resection, packing, hepatic artery ligation and even liver transplantation have been described for this condition.

PATIENTS AND RESULTS

We report a series of five cases, three of which were associated with pregnancy and two with no identifiable pathology. Pre-operative diagnosis was not made in any of these cases.Two of the five patients had hepatic resection, two had peri-hepatic packing and one was treated with laparoscopic drainage.

DISCUSSION

From our experience we conclude that no single form of treatment is applicable to all cases of hepatic rupture.The treatment should be individualised,depending on the extent of hepatic rupture and the expertise available, to obtain best outcome.

Expression of interleukin 7 (IL-7) mRNA and protein in the normal adult human liver: implications for extrathymic T cell development

Interleukin-7 (IL-7) has been shown to play an essential role in T-cell development. Recombinase-activating gene (RAG)-1, RAG-2 and pre-TCR-alpha expression in the normal adult human liver (AHL), together with the presence of lymphoid-haematopoietic progenitors, is strong evidence that the AHL supports T cell maturation. We investigated IL-7 mRNA and protein levels in order to determine whether AHL could support T lymphocyte differentiation. Biopsies were snap frozen, powdered, and RNA/protein extracted. Reverse transcriptase polymerase chain reaction was used to detect IL-7 using primers that amplified 620 base pair (bp) fragments and other smaller transcripts. A sandwich enzyme-linked immunosorbent assay was developed to quantify IL-7 protein in homogenates. The anatomic distribution of IL-7-secreting cells was determined by immunohistochemistry. IL-7-specific product (620 bp) was detected in nine of ten samples, with six also positive for a smaller splice-variant (488 bp). Levels of the 620 bp product were 2.5 times greater than the 488 bp fragment. IL-7 protein was detected in all samples (range 18.47-76.93 pg/100 mg tissue). Immunohistochemistry demonstrated IL-7 protein in discrete cells of lymphoid morphology, widely distributed throughout the parenchyma and within portal tracts. Large populations of innate T cells are found in normal AHL, some of which may differentiate locally. The presence of IL-7 RNA and protein throughout normal hepatic tissue provides evidence that the normal AHL is a suitable microenvironment for T cell differentiation.

Isolation of lymphocytes from normal adult human liver suitable for phenotypic and functional characterization

Murine and human studies have demonstrated that the normal liver contains significant numbers of resident lymphocytes that have functions distinct from those found in blood and other organs. To characterize these cells requires the isolation of viable lymphocytes that can be analysed by flow cytometry and in functional assays. The techniques classically used to isolate single cell suspensions of hepatic lymphocytes for phenotypic and functional studies involve mechanical and/or enzymatic dissociation of liver tissue. The aim of this study was to determine the effect of these procedures on surface molecule expression and lymphocyte function and to optimise an isolation technique that minimises these effects. Mechanical homogenisation of liver tissue alone resulted in low viable lymphocyte yields but these were improved by the combined use of mechanical and enzymatic techniques. A mean yield of 2.3 x 10(6) lymphocytes with a mean viability was 88.8% was obtained from 200 mg wedge biopsy samples of normal adult human liver using a combination of gentle mechanical dissociation followed by digestion with collagenase type IV and DNase I. These cells were suitable for phenotypic characterisation by flow cytometry. They also retained their ability to grow in vitro, to respond to cytokines and activation stimuli, to mediate cytotoxic killing of target cells, and to produce inflammatory and regulatory cytokines.

The role of hepatic arterial Doppler ultrasound after liver transplantation: an 'audit cycle' evaluation

AIMS

To compare the diagnostic performance of hepatic arterial (HA) Doppler ultrasound post-liver transplantation for hepatic artery thrombosis and stenosis in our unit with the literature. To evaluate the role of the technique in clinical practice.

MATERIALS AND METHODS

In a two-phase 'audit cycle' study, adult OLT patients had Doppler studies comprising detection of HA flow and measurements of peak systolic velocity, resistive index and systolic acceleration time. In phase I, patients had Doppler examinations 'routinely' and for any hepatic biochemical abnormality. In phase II, Doppler ultrasound was performed early post-OLT and later only if a senior transplant clinician suspected graft ischaemia. In addition to HA measurements the waveform was visually assessed. Clinical outcome was the 'gold standard'.

RESULTS

Phase 1: 38 patients, 40 OLT operations, 125 Doppler studies; 14 arteriograms. Phase 2: 35 patients, 42 OLT operations, two HA angioplasties, one HA revision, one non-occlusive thrombus, 140 studies; 17 arteriograms. Results; Phase 1 [Phase 2]: sensitivity 80% [100%]; specificity 71% [81%]; PPV 28% [56%]; NPV 96% [100%]; incidence of HA abnormality 12.5% [19. 5%]; likelihood ratio of negative result 0.28 [0]; of positive result 2.8 [5.3].

CONCLUSION

Previously reported results are reproducible. Normal HA waveform should also be a criterion of normality. The technique is very sensitive but relatively non-specific. Predictive values improve with discriminate use. MacEneaney, P. M. (2000). Clinical Radiology55, 517-524.

Differential expression of lymphoid and myeloid markers on differentiating hematopoietic stem cells in normal and tumor-bearing adult human liver

The presence and phenotype of lineage-committed hematopoietic progenitors in the normal adult human liver (AHL) were investigated and compared with the profiles of differentiating hematopoietic precursor populations detected in liver bearing metastases of colonic origin. Levels of hematopoietic stem cells (HSCs) (CD34(+)CD45(+)) detected in hepatic mononuclear cell (HMNC) populations were increased 6-fold when compared with matched peripheral blood samples. In normal liver, less than 5% of HSCs expressed the myeloid-associated antigen, CD33, whereas considerable proportions expressed lymphoid-associated markers (T cell, 33.39%; B cell, 17.39%; and natural killer [NK] cell, 37.17%). Significant increases were observed in the relative proportions of hepatic HSCs coexpressing CD33 (20.53%; P =.001), and the T-cell marker (CD7, 58. 13%; P =.02) in tumor-bearing liver compared with normal liver. HSCs with B-cell progenitor phenotype (CD19(+)) were significantly decreased in tumor-bearing liver (0.06%; P =.02). Despite these differences, the activation status of hematopoiesis, as measured by the coexpression of the differentiation and activation markers, CD38 and CD45RA, did not differ significantly between normal and tumor-bearing liver. These results indicate that the normal AHL harbors lineage-committed hematopoietic progenitors, and the vast majority of these progenitors express lymphoid-associated antigens with changes occurring in both the myeloid and lymphoid compartments of the hepatic hematopoietic pathway on tumor challenge. While tumor-bearing livers are enriched for intrahepatic myeloid precursors and T-cell progenitor cells, further studies are required to establish the origin and in situ development potential of hepatic HSCs in the adult human and their role in tumor immunity.

The human liver contains multiple populations of NK cells, T cells, and CD3+CD56+ natural T cells with distinct cytotoxic activities and Th1, Th2, and Th0 cytokine secretion patterns

The human liver contains significant numbers of T cells, NK cells, and lymphocytes that coexpress T and NK cell receptors. To evaluate their functional activities, we have compared the cytotoxic activities and cytokines produced by normal adult hepatic CD3+CD56- (T) cells, CD3-CD56+ (NK) cells, and CD3+CD56+ (natural T (NT)) cells. In cytotoxicity assays using immunomagnetic bead-purified NK cell, T cell, and NT cell subpopulations as effectors, fresh hepatic NK cells lysed K562 targets, while NT cells could be induced to do so by culturing with IL-2. Both NT and T cells were capable of redirected cytolysis of P815 cells using Abs to CD3. Flow cytometric analysis of cytokine production by fresh hepatic lymphocyte subsets activated by CD3 cross-linking or PMA and ionomycin stimulation indicated that NT cells and T cells could produce IFN-gamma, TNF-alpha, IL-2, and/or IL-4, but little or no IL-5, while NK cells produced IFN-gamma and/or TNF-alpha only. The majority of NT cells produced inflammatory (Th1) cytokines only; however, approximately 6% of all hepatic T cells, which included 5% of Valpha24 TCR-bearing NT cells and 2% of gammadeltaTCR+ cells, simultaneously produced IFN-gamma and IL-4. The existence of such large numbers of cytotoxic lymphocytes with multiple effector functions suggests that the liver is an important site of innate immune responses, early regulation of adaptive immunity, and possibly peripheral deletion of autologous cells.

In vitro evidence for the presence of hematopoietic stem cells in the adult human liver

Previous studies have identified novel lymphoid phenotypes in the adult human liver and provided evidence to suggest that lymphoid differentiation can occur locally in this organ. The aim of this study was to examine the adult human liver for the presence of hematopoietic stem cells that may provide the necessary precursor population for local hematopoietic and lymphoid differentiation. Hepatic mononuclear cells (HMNC) were extracted from normal adult liver biopsy specimens using a combination of mechanical disruption and enzymatic digestion. The stem cell marker CD34 was found on 0.81% to 2.35% of isolated HMNCs by flow cytometry. CD34(+) HMNCs were positively selected using magnetically labeled beads, and the enriched population was further examined for surface markers characteristically expressed by immature hematopoietic cells and early progenitors. CD45 was expressed by 49% (+/-23%) of CD34(+) HMNCs, indicating their hematopoietic origin. CD38, one of the first markers to be expressed by developing progenitor cells was found on 50% (+/-22%) of CD34(+) HMNCs indicating the presence of both pluripotent stem cells and committed precursors. The majority (90%) of CD34(+) HMNCs coexpressed the activation marker human leukocyte antigen DR, consistent with actively cycling cells. Functional maturation of these hepatic progenitors was shown by the detection of multilineage hematopoietic colony formation after tissue culture. Erythroid (BFU-E), granulocyte-monocyte (CFU-GM), and mixed colonies (CFU-GEMM) were detected after culture of unseparated HMNCs and the enriched CD34(+) HMNC population; 14.3 +/- 13.2 (mean +/- SD) BFU-E, 3.1 +/- 3.1 CFU-GM, and 0.4 +/- 0.9 CFU-GEMM per 1 x 10(5) unseparated HMNCs and 16.0 +/- 9.5 BFU-E and 1.7 +/- 0.9 CFU-GM were identified per 2.4 x 10(3) CD34(+) HMNCs plated. The detection of surface markers characteristic of immature hematopoietic cells and colony formation in tissue culture provides evidence for the presence of hematopoietic stem cells and early progenitor cells in the adult human liver. This would suggest that the adult human liver continues to contribute to hematopoiesis and may be an important site for the differentiation of lymphohematopoietic cells involved in disease states, such as autoimmune hepatitis and graft rejection after liver transplantation.

Natural T cells in the human liver: cytotoxic lymphocytes with dual T cell and natural killer cell phenotype and function are phenotypically heterogenous and include Valpha24-JalphaQ and gammadelta T cell receptor bearing cells

The adult liver contains lymphocytes with a unique phenotypic distribution compared to blood and other organs. We have characterized a human lymphocyte population that exhibits dual T cell and natural killer (NK) cell phenotype and function, denoted natural T (NT) cells, in nine normal adult liver specimens. Flow cytometry revealed that up to 55% (mean 27%) of hepatic (but <6% of peripheral) CD3+ lymphocytes expressed CD56, CD161 and/or one or more of the killer inhibitory receptors (KIR) p58.1, p58.2, p70 and CD94. NK function was attributed to the CD3+CD56+ cells by the demonstration that hepatic, but not peripheral, CD3+ lymphocytes could be induced to lyse NK-sensitive K562 target cells, while CD56- cells from both compartments could not. Three color flow cytometric analysis of fresh hepatic cells indicated that CD3+CD56+ NT cells can be either CD8+, CD4+ or CD4 CD8-, they express alphabeta or gammadelta T cell receptors (TCR) and CD161 and KIRs, but rarely CD16. Hepatic NT cells predominantly express the mature/activated CD45RO and CD56dim phenotypes. Analysis of mRNA production by isolated NT cells indicated a preferential usage of the invariant CD1-restricted Valpha24-JalphaQ TCR. The presence of such large numbers of chronically activated NT cells provides compelling evidence that the liver has unique immunoregulatory functions.

Effect of a no-conversion policy on patient outcome following laparoscopic cholecystectomy

Low molecular weight heparin and unfractionated heparin in thrombosis prophylaxis after major surgical intervention: update of previous meta-analyses

D. Bergqvist, Department of Surgery, University Hospital, S-751 85 Uppsala, Sweden

Authors' reply N. Victor, Universität Heidelberg, Abteilung Medizinische Biometrie, Im Nuenheimer Feld 305, D-69120 Heidelberg, Germany

Effect of a no-conversion policy on patient outcome following laparoscopic cholecystectomy

K. Barry, J. Hyland, O. Traynor, Department of Surgery, St Vincent's Hospital, Elm Park, Dublin 4, Ireland

Authors' reply P. J. O'Dwyer, Department of Surgery, Western Infirmary, Glasgow G11 6NT, UK

Magnetic resonance imaging in evaluation of the common bile duct

S. Sudhindran, Department of Surgery, Countess of Chester Hospital, Liverpool Road, Chester CH1 3ST, UK

Authors' reply M. Musella, Experimental and Clinical Medicine Department, University of Reggio Calabria-Catanzato Medical School, 88 100 Catanzaro, Italy

Prognostic factors in a series of 297 patients with gastric adenocarcinoma undergoing surgical resection

D. F. Hewin, Department of Surgery, Royal Devon and Exeter Hospital, Barrack Road, Exeter EX2 5DW, UK

Pilonidal sinus: experience with the Karydakis flap

J. Bascom, Millrace Medical Building, 655 East 11th Avenue – Suite 5, Eugene, Oregon 97 401-3663, USA

Topical glyceryl trinitrate cream for anal fissure

J. W. F. Catto, F. L. Hinson, S. H. Leveson, Department of Surgery, York District Hospital, York YO3 7HE, UK

Long-term oral administration of branched chain amino acids after curative resection of hepatocellular carcinoma: a prospective randomized trial

D. V. Mann, Department of Surgery, Prince of Wales Hospital, Chinese University of Hong Kong, Shatin, Hong Kong

Anatomical variants during axillary dissection

I. Daniels, I. Timms, G. Querci della Rovere, Breast Unit, Royal Marsden NHS Trust, Downs Road, Sutton SM2 5PT, UK

Resident human hepatic lymphocytes are phenotypically different from circulating lymphocytes

BACKGROUND/AIMS

Murine and human studies have documented the existence of subpopulations of lymphocytes in particular tissues that differ phenotypically and functionally from those in peripheral blood and may mature locally. Since little is known about lymphocyte subpopulations in the normal human liver, we have analysed the surface phenotypes of lymphocytes isolated from liver specimens taken from 15 donors at the time of liver transplantation, and compared these with those of peripheral blood lymphocytes.

METHODS

Hepatic lymphocytes were prepared by mechanical dissociation and enzymatic digestion of liver tissue. The cells were stained with a panel of monoclonal antibodies (CD3, CD4, CD8, CD19, CD56, gammadeltaTCR, alphabetaTCR, CD8alpha-chain, CD8alphabeta dimer), and analysed by flow cytometry. In situ characterisation of hepatic lymphocytes was by haematoxylin and eosin staining of fixed liver sections and by immunohistochemical staining for common leukocyte antigen and CD3.

RESULTS

Significant numbers of hepatic T lymphocytes were localised to the portal tracts and parenchyma of normal liver specimens. Flow cytometry revealed that the CD4/CD8 ratio (1:3.5) was consistently reversed compared with that in peripheral blood (2:1). Other lymphocyte populations identified include double positive CD3+CD4+CD8+ cells which accounted for a mean of 5.5% (range 3-11.6%) of hepatic CD3+ cells compared with 1.3% in blood (range 0.7-3.6%; p < 0.007), and double negative CD3+ CD4-8- cells (14.5%; range 2.7-29% compared with 5.0%; range 2.1-10.8%, p < 0.02). Over 15% (range 6.8-34%) of all hepatic CD3+ cells expressed a gammadeltaTCR compared to 2.7% (range 0.9-4.7%) of CD3+ peripheral blood lymphocytes (p < 0.004) and almost 50% of these coexpressed CD8. The CD8 alpha-chain was expressed without the beta-chain (CD8alpha+beta-) by 15.4% (range 4-29.1%) of hepatic T cells, but this phenotype was undetectable among peripheral blood lymphocytes (p < 0.009). Cells expressing both the T cell marker CD3 and the natural killer cell marker CD56 constituted 31.6% (range 14-54%) of all hepatic CD3+ lymphocytes but were rarely present amongst peripheral blood lymphocytes (0-6%; p < 0.0001).

CONCLUSIONS

These data are the first to describe and quantify unconventional T lymphocyte subpopulations in the normal adult human liver which may have specialised functions in regional immune responses and which may differentiate locally. These findings have important implications for our understanding of hepatic immunoregulation and the pathogenic mechanisms involved in viral and immune-mediated liver disease and allograft rejection.

Orthotopic liver transplantation for veno-occlusive disease complicating autologous bone marrow transplantation

BACKGROUND

Veno-occlusive disease of the liver is a serious and often life-threatening complication after bone marrow transplantation. Although risk factors for the development of veno-occlusive disease have been postulated, there is no precise method for accurately identifying those patients who are at risk and for whom early intervention and treatment would have maximum potential benefit. Liver transplantation has been advocated as a treatment for veno-occlusive disease in selected patients.

METHODS

In this report, we describe a patient who underwent liver transplantation for life-threatening veno-occlusive disease after autologous bone marrow transplantation for acute lymphoblastic leukemia.

RESULTS

Liver engraftment was achieved, but the patient developed Pneumocystis pneumonia, which failed to respond to pentamidine. The patient died 6 months after liver transplantation.

CONCLUSIONS

While acknowledging the limited experience of orthotropic liver transplantation in this patient population, we suggest its consideration as a feasible, potentially beneficial treatment option in patients with severe veno-occlusive disease after bone marrow transplantation.

Delayed correction of portal hypertension after portal vein conduit arterialization in liver transplantation

A 55-year-old woman underwent orthotopic liver transplantation for autoimmune chronic active hepatitis. Extensive portal and superior mesenteric venous thrombosis precluded standard portal venous reconstruction and necessitated use of a venous conduit from the recipient splenic vein of the donor liver. Flow through this conduit was poor, however, and to prevent subsequent portal venous thrombosis and graft loss, the conduit was arterialized by end-to-side anastomosis with the recipient hepatic artery. This ensured graft survival but resulted in prehepatic portal hypertension, which required ligation of the arterioportal fistula for 4 months. The patient had a satisfactory outcome.