John A. Windsor

Minimally invasive pancreatic necrosectomy

It is timely, a decade after the first reports of minimally invasive necrosectomy (MIN), to review the progress of this procedure that now encompasses radiological, endoscopic and percutaneous techniques. The main impetus towards MIN has been the recognition that open necrosectomy often makes patients sicker and that outcome may be improved when necrosectomy is delayed 1 . The situation is also influenced by the recent recognition that almost all patients with sterile pancreatic necrosis and some with infected necrosis 2 can be managed without necrosectomy. The development of MIN has led to two contrasting philosophies. The first advocates an orthodox ‘step-down’ approach in which open necrosectomy plays a primary role, with less invasive methods used for residual or subsequent collections. The second, or ‘step-up’, approach relies initially on less invasive techniques, with open necrosectomy used as a last resort. A multicentre randomized controlled trial comparing these two approaches is already under way in the Netherlands 3 . The challenges facing this trial include the variation in expertise with MIN and in the definitions of target lesions. Variations in the target lesions (location, fluid/mixed/solid, early/late, sterile/infected, single/ multiple, wall thickness) and in the patients (co-morbidity, habitus, degree of organ dysfunction) require an individually tailored and flexible approach to the treatment of pancreatic necrosis. MIN can be classified by the type of scope used (flexible endoscope, laparoscope, nephroscope) and the route of access (transperitoneal, transgastric, retroperitoneal). Nine possible combinations exist and, except for the endoscopic transperitoneal approach, all have been attempted. Each of the scopes and access routes has its advantages and disadvantages. The scopes can be compared for field of view, working channel for instruments and irrigation, external diameter, length, and flexibility and angulation. The routes can be compared for ease of access, risk of collateral injury and unnecessary contamination, and the ability to deal with multiple and complex collections. The two approaches that have risen to favour are the endoscopic transgastric and nephroscopic retroperitoneal routes, probably because they are based on conventional operations. The former is an adaptation of an

Phrenoesophageal ligament re-visited

The phrenoesophageal ligament, attaching the esophagus to the diaphragm, has been given little emphasis in anatomy teaching. This study was undertaken to examine the macroscopic and microscopic structure of the phrenoesophageal ligament. The results indicate that the ligament is a distinct structure bridging the space between the esophageal wall and the margins of the esophageal hiatus. This ligament appears to arise from both the endothoracic fascia and the transversalis fascia and is composed of abundant collagen and elastic lamellae. Toward the wall of the esophagus, the ligament divides into a prominent upper leaf and an ill‐defined lower leaf before inserting into the wall of the esophagus. Histological study reveals that the ligament has a substantial and deep insertion into the wall of the esophagus. It appears that the ligament plays an important role in anchoring the lower esophagus and maintaining gastroesophageal competence. Clin. Anat. 12:164–170, 1999.

Proteolysis in severe sepsis is related to oxidation of plasma protein.

OBJECTIVE To test the hypothesis that the oxidation of proteins is part of the mechanism of proteolysis in catabolic states. DESIGN Prospective, observational study. SETTING Critical care unit at a university teaching hospital, New Zealand. PATIENTS 13 patients (6 male, 7 female; median age 61, range 26-76 years) who were admitted to the Department of Critical Care Medicine at Auckland Hospital with a diagnosis of severe sepsis. The median APACHE II score during the first 24 hours after admission was 22 (range 15-34). Control values of protein carbonyl in plasma were established in 15 healthy volunteers. INTERVENTIONS We made serial measurements of total body protein (by neutron activation analysis) and plasma protein carbonyl (by ELISA) concentrations over a period of 10 days. MAIN OUTCOME MEASURE Plasma protein carbonyl concentration and total body protein. RESULTS The total amount of body protein decreased significantly over the 10 days (p < 0.001). Plasma protein carbonyl concentrations were significantly higher in the septic patients than in the control group throughout the study period (p < 0.0001). There was a significant reduction in plasma protein carbonyl concentration over the study period (p < 0.008). The early increase in the concentration of protein carbonyl formation was followed by an ongoing loss of body protein. There was a significant positive correlation between total body protein and plasma protein carbonyl (p < 0.03). CONCLUSIONS Severe sepsis results in oxidation of plasma proteins and this precedes and is related to the loss of body protein.

Small bowel ischaemia-reperfusion increases plasma concentrations of oxidised proteins in rats

OBJECTIVES To find out whether plasma concentrations of protein carbonyl (a specific marker of oxidative damage of proteins) are increased during intestinal ischaemia-reperfusion and whether they are correlated with von Willebrands factor (vWF, a marker of endothelial injury) or myeloperoxidase (a marker of neutrophil activation). DESIGN Randomised experimental study. SETTING University department of surgery, New Zealand. ANIMALS Thirty anaesthetised adult Wistar rats. INTERVENTIONS The sham operated group (n = 10) had laparotomy and isolation of the superior mesenteric artery without clamping. The ischaemia-reperfusion group (IR, n = 10) had the superior mesenteric artery clamped for 1 hour and reperfusion for 15 minutes. The control group (n = 10) had direct puncture of the heart to sample blood. MAIN OUTCOME MEASURES Plasma concentrations of protein carbonyl, vWF, and myeloperoxidase. RESULTS Plasma protein carbonyl concentrations were significantly higher in the IR group than in the sham group (p < 0.02, Mann-Whitney test, median (range) 0.187 (0.141-0.242) compared with 0.144 (0.121-0.185) nmol/mg) and in the control group (p < 0.01, Mann-Whitney test, median (range) 0.187 (0.141-0.242) compared with 0.136 (0.108-0.175) nmol/mg). There was a significant correlation between protein carbonyl and vWF concentrations (r = 0.54, F = 10.9, p < 0.003, linear regression) but not with those of myeloperoxidase. CONCLUSION Intestinal ischaemia-reperfusion caused an increase in the plasma protein carbonyl concentration, which is possibly produced by endothelial cells.

The iliopubic tract: an important anatomical landmark in surgery

A band of fascial thickening, termed the iliopubic tract, lies on the posterior aspect of the inguinal region and has been described in the surgical literature as playing an important role during herniorraphy. This study was undertaken to examine the gross and microscopic anatomy of the iliopubic tract in 12 cadavers. The results confirmed that the iliopubic tract can be readily identified as a thickening of the transversalis fascia running deep and parallel to the inguinal ligament. It attaches to the superomedial part of the pubic bone medially, but laterally its fibres fan out within the fascia transversalis and fascia iliaca without bony attachment to the iliac spines. In contrast to the inguinal ligament, the histological analysis of the iliopubic tract shows a high elastin to collagen ratio. The functional signficance of this structure merits further study, but there is no doubt that it is important in many approaches to inguinal herniorraphy. For this reason it is considered that the iliopubic tract deserves greater emphasis in the anatomy teaching of the inguinal region.

Plasma von Willebrand Factor and Intestinal Ischaemia-Reperfusion Injury in Rats

The purpose of this study was to determine whether plasma von Willebrand factor concentrations are correlated with the degree of intestinal ischaemia-reperfusion injury. Forty-six anaesthetised adult Wistar rats were divided into five groups. The sham-operated group (S, n=10) had laparotomy and isolation of the superior mesenteric artery without clamping. Three ischaemia-reperfusion groups (n=10 in each) had clamping of the superior mesenteric artery for 15, 30, and 45 minutes, respectively, and reperfusion for 15 minutes. A control group (C, n=6) had direct puncture of the heart to sample blood. Mean arterial pressure was measured continuously. Blood was collected at the end of the study to measure von Willebrand factor. The small bowel injury was graded histologically. There was a significant systemic hypotension after declamping in all ischaemia-reperfusion groups, which had a high negative correlation with the histological score (R=-0.46, F=10.1, p<0.003, simple linear regression). Plasma von Willebrand factor was significantly elevated in the three ischaemia-reperfusion groups compared with the control group but not significantly different from the sham-operated group (mean von Willebrand factor concentration (SEM): 156 (29), 283 (29), 295 (25), 381 (44), and 366 (40)% in C, S, ischaemia-reperfusion 15, ischaemia-reperfusion 30, and ischaemia-reperfusion 45 groups, respectively). The concentration of von Willebrand factor was not correlated to the histological score (R=0.22, F=1.83, p<0.2) or the degree of hypotension after the removal of the clamp (R=-0.22, F=1.8, p<0.2, simple linear regression). This study shows that von Willebrand factor concentration does not correlate with the degree of intestinal ischaemia-reperfusion injury. It is unlikely that von Willebrand factor can be used as a predictor of disease severity.