John S. Hammond

Prediction, prevention and management of postresection liver failure

Postresection liver failure (PLF) is the major cause of death following liver resection. However, there is no unified definition, the pathophysiology is understood poorly and there are few controlled trials to optimize its management. The aim of this review article is to present strategies to predict, prevent and manage PLF.

Scaffolds containing growth factors and extracellular matrix induce hepatocyte proliferation and cell migration in normal and regenerating rat liver

BACKGROUND & AIMS Intrahepatic drug delivery from implantable scaffolds is being developed as a strategy to modulate growth and enhance regeneration at the time of liver resection. In this study we examine the effects of scaffolds containing hepatocyte growth factor, epidermal growth factor, fibroblast growth factor 1, fibroblast growth factor 2, and liver-derived extracellular matrix (L-ECM) when implanted into normal and partially hepatectomized rat livers. METHODS Scaffolds loaded with combinations of growth factors and L-ECM were implanted into normal livers (controls=L-ECM, polymer or sham) and livers following partial hepatectomy (controls=partial hepatectomy or sham). The primary end points were hepatocyte DNA synthesis and liver tissue penetration into scaffolds. Secondary end points included non-parenchymal cell DNA synthesis, liver weight analysis, liver function, and histological characterisation of the peri-implant parenchyma. RESULTS Four days after implantation in normal livers, there was significantly more hepatocyte proliferation around growth factor scaffolds than controls. Seven days after implantation, there was significantly more tissue penetration into growth factor scaffolds than control scaffolds. ED-1 and desmin positive cells were present in the pores of scaffolds. Two days after partial hepatectomy, there was significantly more hepatocyte proliferation around scaffold implanted livers than after partial hepatectomy alone. CONCLUSIONS Growth factors and L-ECM accelerated non-parenchymal cell migration into scaffolds and increased hepatocyte and non-parenchymal cell proliferation around them. These results demonstrate the potential for intrahepatic implantation of scaffolds containing growth factors and L-ECM to modulate growth in the normal and regenerating liver.

Scaffolds for liver tissue engineering.

This review focuses on the expanding role for biomaterials and polymer scaffolds in liver tissue engineering. Studies are subdivided into in vitro and in vivo approaches. The in vitro section of the review discusses the challenges specific to liver tissue engineering, and how the choice of scaffold and its structure influences the success of the regenerative medicine strategy. The in vivo section evaluates early attempts to stimulate liver repair with cell and growth factor therapies, their failings and how current approaches aim to solve these problems.

Comparison of liver parenchymal ablation and tissue necrosis in a cadaveric bovine model using the Harmonic Scalpel™, the LigaSure™, the Cavitron Ultrasonic Surgical Aspirator® and the Aquamantys® devices

OBJECTIVES The amount of tissue that is ablated or necrosed at the line of parenchymal transection is of clinical significance in the interpretation of resection margin status following hepatic resection. The aim of this study was to define the extent of parenchymal ablation and necrosis in liver tissue using the Harmonic Scalpel, the LigaSure, the Cavitron Ultrasonic Surgical Aspirator (CUSA) and the Aquamantys dissector ex vivo. METHODS Mounted blocks of non-perfused bovine liver were transected using the Harmonic Scalpel, LigaSure, CUSA and Aquamantys devices. Outcome measures included parenchymal ablation (ablation band widths and weights) and tissue necrosis band widths along the line of transection. Each experiment was replicated five times. RESULTS All devices were associated with parenchymal ablation (Harmonic Scalpel, 4.73 ± 1.62 mm; LigaSure, 4.55 ± 2.02 mm; CUSA, 7.16 ± 2.87 mm; Aquamantys, 4.75 ± 1.43 mm) and tissue necrosis (Harmonic Scalpel, 1.07 ± 0.46 mm; LigaSure, 1.36 ± 0.36 mm; CUSA, 0.81 ± 0.21 mm; Aquamantys, 0.81 ± 0.36 mm). CONCLUSIONS The Harmonic Scalpel, LigaSure, CUSA and Aquamantys devices were associated with bands of tissue loss along the hepatic parenchymal transection line in this benchtop cadaveric model. This should be taken into account in the interpretation of resection margin status following liver resection.

Impact of portal vein infiltration and type of venous reconstruction in surgery for borderline resectable pancreatic cancer

The International Study Group of Pancreatic Surgery (ISGPS) recommends operative exploration and resection of pancreatic cancers in the presence of reconstructable mesentericoportal axis involvement. However, there is no consensus on the ideal method of vascular reconstruction. The effect of depth of tumour invasion of the vessel wall on outcome is also unknown.

Surgical endoscopy training: the Joint Advisory Group on gastrointestinal endoscopy national review

Background and aims Endoscopy performance is dependent on the technical ability and experience of the operator. There is anxiety among surgical trainees that certification to perform independent endoscopy to agreed national standards by the date of award of certificate of completion of training is not achievable. The aim of this study was to evaluate the delivery of endoscopy training to UK-based general surgery trainees. Materials and methods An electronic survey of general surgery trainees holding a national training number or in a locum appointment to training post between July and September 2010 was undertaken. Results Two hundred and thirty-three trainees responded from all UK training regions. Stated subspeciality interests included coloproctology (47%), oesophagogastric/bariatric (22%) and hepatobiliary/pancreatic (10%) general surgery. 92% of trainees were training or planned to train in endoscopy, 62% of whom had registered with the Joint Advisory Group (JAG). Thirteen trainees had JAG certification in diagnostic upper GI endoscopy and eight in colonoscopy. There were high rates of dissatisfaction with endoscopy training nationally. Two thirds of trainees had no scheduled training lists. Conflicting elective/emergency commitments, competition and absence of training lists were the most common reasons for a failure to access endoscopy training. Conclusions Higher surgical trainees are failing to achieve national standards for endoscopy practice. There is an urgent need to address the deficiencies in endoscopy training to ensure a competent cohort of surgical endoscopists.

Emerging roles for biomaterials in the treatment of liver disease

This review explores potential roles for biomaterials in the field of liver surgery and hepatology. The studies reviewed are presented in three sections. The first section discusses liver regeneration and strategies to modulate it. The second section outlines the pathophysiology of liver inflammation and fibrosis and highlights novel therapeutic targets. The final section summarises the current challenges in liver surgery and discusses how biomaterials may be used to address these challenges and focuses on early translational applications for biomaterials for drug delivery and liver surgery.