[Computer assisted surgery, 2001 development and prospects. Results of a congress at Reisensburg Castle, 23-24 November 2000]]. / Computer assistierte Chirurgie, Entwicklung und Perspektiven 2001. Ergebnisse einer Arbeitstagung auf Schloss Reisensburg, 23./24.11.2000.

The progress in computer assisted surgery (CAS) is influenced by new technologies in imaging as well as by the input of the users. At present, CAS procedures are established in dorsal spine instrumentation, prosthetics and long bone surgery. Present status and future of CAS was a topic of an expert meeting at the Reisensburg castle. Imaging will speed up in the future using multi-detector techniques. C-arm navigation will gain more information using the 3D technology intraoperatively. CT based navigation procedures are standard in spine and will be established in pelvic surgery. CAS in robotics at the moment means the use of robot-assistance. A new concept is the modality-based navigated surgery, which can be used at various skeletal locations. Visualization of patient data will improve using 3D semi-transparencies with real time update. In the future it will be mandatory to find algorithms to fuse the different possibilities and techniques. A new concept of surgical training is necessary to teach CAS procedures. Therefore discussion must go on to improve these systems.

[Computer-assisted surgery: developments and prospects in 2001. Results of a workshop at Schloss Reisenburg, 23-24 November 2000]. / Computer assistierte Chirurgie, Entwicklung und Perspektiven 2001. Ergebnisse einer Arbeitstagung auf Schloss Reisenburg, 23./24.11.2000.

The progress in computer assisted surgery (CAS) is influenced by new technologies in imaging as well as by the input of the users. At present, CAS procedures are established in dorsal spine instrumentation, prosthetics and long bone surgery. Present status and future of CAS was a topic of an expert meeting at the Reisensburg castle. Imaging will speed up in the future using multi-detector techniques. C-arm navigation will gain more information using the 3D technology intraoperatively. CT based navigation procedures are standard in spine and will be established in pelvic surgery. CAS in robotics at the moment means the use of robot-assistance. A new concept is the modality-based navigated surgery, which can be used at various skeletal locations. Visualization of patient data will improve using 3D semi-transparencies with real time update. In the future it will be mandatory to find algorithms to fuse the different possibilities and techniques. A new concept of surgical training is necessary to teach CAS procedures. Therefore discussion must go on to improve these systems.

Short-bowel syndrome - surgical treatment with long-term benefit?

Survival and management of patients with irreversible intestinal failure has been made possible by the development of total parenteral nutrition (TPN). Despite the progress of TPN severe and even fatal complications might occur. Different non-surgical and surgical therapies can be employed to either improve intestinal function or restore enteral autonomy to obviate the need for TPN. A comprehensive review of the pertinent literature on different treatment modalities for short-bowel syndrome and our own experience are presented to judge long-term benefit and make recommendations on up-to-date surgical management.

Heterotopic intestinal transplantation aggravates the insult of chronic rejection.

BACKGROUND: Intestinal grafts are placed either heterotopically (out of continuity) or orthotopically (in continuity); the latter is believed to be advantageous, as intraluminal nutrients and intestinal secretions might modulate the intestinal immune status and possibly delay rejection. METHODS: This study was designed to delineate the effects of heterotopic versus orthotopic allograft position on the morphology and function of intestinal smooth muscle in our rat model of chronic rejection. Syngeneic orthotopic grafts were evaluated to control for changes due to the transplantation process. RESULTS: Histochemistry of the graft's muscularis externa showed a significant thickening due to hyperplasia and hypertrophy, which was most pronounced in heterotopic grafts (control = 92+/-2.4 microm, syngeneic grafts = 140+/-6.7 microm, orthotopic allografts = 278+/-26.6 microm, heterotopic allografts = 456+/-50 microm). In terms of function, muscle strips from allografts only generated 23% of the total bethanechol-induced contractile force in vitro compared to unoperated controls and syngeneic grafts. The mean resting membrane potential of control and isograft muscle cells was -69 +/- 0.9 mV with a slow-wave amplitude of 20+/-0.5 mV. Chronic rejection hyperpolarized the resting membrane potential of orthotopic allografts (-66 +/- 0.5 mV) and even more so of heterotopic allografts (-58 +/- 3.4 mV). Slow-wave amplitudes were decreased in orthotopic (14+/-0.9 mV) and nearly abolished in heterotopic allografts (2+/-1.2 mV). CONCLUSIONS: Our data indicate that allografts in heterotopic position are most susceptible to the insult of chronic rejection exemplified by increased proliferative and hypertrophic transformation of intestinal smooth muscle and a marked decrease in mechanical and electrical activity.

Chronic rejection causes early destruction of the intrinsic nervous system in rat intestinal transplants.

Chronic rejection is the major cause of late intestinal allograft dysfunction. We have previously shown that chronic rejection alters the muscularis externa of the graft. This study determined structural and functional changes to the enteric nerves during chronic rejection. Chronic rejection was achieved in orthotopic intestinal transplants (ACI to Lewis) by limited immunosuppression. Syngeneic transplants (ACI to ACI) and unoperated ACI rats served as controls. Animals were clinically healthy and showed no significant alterations in the mucosal architecture on postoperative day 90. Staining for NADPH diaphorase activity (nitric oxide synthase-containing neurons) and with neurofilament antibody RT-97 revealed that chronic rejection decreased the number of jejunal myenteric ganglia by approximately 50%. Inhibitory junction potentials (IJPs) to circular muscle cells were determined by electrical field stimulation (EFS). In controls and syngeneic grafts, EFS caused a stimulus-dependent increase in IJP amplitude, with a maximal amplitude of 9 +/- 0.4 and 10 +/- 0.8 mV, respectively. Chronic rejection in allografts markedly increased the threshold for IJP initiation and decreased the maximal IJP amplitude (5 +/- 0.8 mV). Our data indicate that chronic rejection severely damages the muscularis and the enteric nervous system before mucosal changes become evident.

Increased expression of interferon-gamma in a rat model of chronic intestinal allograft rejection.

Chronic rejection remains a major cause of late graft dysfunction. Although much research has focused on acute rejection, little is known about the mechanisms of chronic rejection. Our group has recently reported evidence of significant intestinal smooth muscle hypertrophy and hyperplasia associated with abnormal contractile and electrical activities in a rat model of chronic intestinal rejection. The changes in the smooth muscle layer are associated with a significant inflammatory infiltrate. In order to further delineate the immune mechanisms of chronic rejection, we sought to clarify the nature of this infiltrate. Orthotopic small bowel transplantation was performed using an allogeneic (ACI-Lewis) rat combination. The rats only received immunosuppression for the first 28 days posttransplantation (cyclosporine 15 mg/kg daily from postoperative day 0 to 6 and every other day from postoperative day 7 to 28). This led to chronic rejection of the graft by day 90, at which time the rats were sacrificed. Analysis by immunohistochemistry revealed NK and CD5+ leukocytes infiltrating the muscular layer. Examination of cytokine production by radiolabeled polymerase chain reaction showed high levels of steady state interferon-gamma mRNA in full thickness intestinal segments and within the isolated muscularis of chronically rejecting intestinal allografts as compared to syngeneic and control grafts. Interferon-gamma mRNA was localized to both the muscularis and mucosa. Interestingly, positively hybridized cells within the muscularis tended to preferentially localize to the myenteric and submucosal plexuses suggesting potential role for this cytokine in chronic intestinal ejection.

[Multicentric gastric carcinoid in autoimmune gastritis]. / Multizentrisches Magenkarzinoid bei Autoimmungastritis.

HISTORY AND FINDINGS: A now 54-year-old woman was 32 years ago found to have immune thrombocytopenia and 3 years ago ANA-positive and HBsAg-negative hepatitis with cirrhotic metaplasia. Numerous small asymptomatic carcinoids with marked hypergastrinaemia (1626 ng/l) were also first found 3 years ago. No gastrinoma could be found. Severe arthralgia was the main symptom on admission. INVESTIGATIONS: Gastroscopy revealed a polypoid carcinoid, 1 cm in diameter. There was total achlorhydria. No pernicious anaemia or carcinoid syndrome was found. TREATMENT AND COURSE: Total gastrectomy with construction of a jejunal substitute stomach was performed. Histology showed typical chronic-atrophic gastritis type A, all stages of an argyrophilic endocrine cell hyperplasia, as well as microcarcinoidosis and multicentric carcinoid, in part with submucosal infiltration and lymph node metastases. Immunohistology revealed immune reaction for the global endocrine marker. No specific hormones were demonstrable in the carcinoid cells. The postoperative course was without complications. Serum gastrin levels have since been normal. CONCLUSIONS: The case confirms the possibility of an achlorhydria-hypergastrinaemia-carcinoid sequence. Now new stage-related therapeutic guidelines for this disease are needed.

[Indications for total parenteral nutrition or small intestine transplantation?--Prognostic factors in short bowel syndrome]. / Indikation zur total parenteralen Ernährung (TPE) oder Dünndarmtransplantation?--Prognosefaktoren beim Kurzdarmsyndrom.

After massive intestinal resection resulting in short bowel syndrome it is often unclear if the patient will remain on total parenteral nutrition (TPN) or regain enteral autonomy. Small bowel transplantation or bowel-lengthening procedures could potentially be a therapeutic option for patients confined to life-long parenteral nutrition. Initiated early in the course of the disease this could prevent frequent serious complications of long-term parenteral nutrition. However, it is unclear which factors determine the outcome of these patients. For further information on the long-term prognosis, data of 33 patients with short bowel syndrome operated in our institution from 1982 to 1995 were retrospectively analyzed and the present status of all living patients evaluated. Gender, age or underlying disease had no influence on the adaptation of the small intestine or the duration of TPN in the surviving patients. Return to enteral autonomy mainly depended upon the length of the remaining small and large bowel. Thus the further course of the disease can be predicted and necessary measures can be taken as this information is always available at the time of initial surgery.

Postoperative selective bowel decontamination prevents gram-negative bacterial translocation in small-bowel graft recipients.

Gram-negative septic episodes are a potential risk of small-bowel transplantation; bacterial translocation through the graft is considered the mechanism. As a measure to prevent this complication, we evaluated postoperative selective bowel decontamination (SBD) in the rat model of orthotopic small-bowel transplantation [Lewis (LEW) and Brown-Norway (BN) rats as donors and recipients]. For 4 days after transplantation we gave FK 506, 2 mg/kg, which prevents rejection and results in indefinite recipient survival. For SBD, 24 mg/kg/day polymyxin E and 20 mg/kg/day tobramycin were administered via orogastric gavage to allograft recipients, both with and without FK 506 therapy. On Day 9, all rats were sacrificed, the peritoneal cavity was swabbed, and mesenteric lymph nodes (MLN), spleen, liver, and ileum were harvested for microbial qualitative and quantitative analysis. Animals with positive peritoneal swab cultures were excluded. SBD resulted in a significant reduction of the quantitative gram-negative bacterial flora in the ileum and cecum and of bacterial translocation to the MLN [0% versus 50% (no FK 506 therapy) and 8% versus 50% (FK 506 treated)]. In the allograft groups not treated with FK 506, SBD failed to significantly prolong survival, suggesting that acute rejection is not hastened by infection (bacterial translocation). We conclude that SBD in small-bowel-graft recipients prevents bacterial translocation by reducing intestinal gram-negative bacterial flora; this may reduce local and systemic infections by gut-derived organisms.

Decreased mucosal IgA levels in ileum of patients with chronic ulcerative colitis.

Patients with chronic ulcerative colitis (CUC) are known to have decreased spontaneous IgA secretion by colonic mononuclear cells. The aim of this study was to determine whether a similar alteration exists in the apparently healthy ileum of patients with CUC. The concentration of IgA was measured in the supernatant from homogenized mucosal ileal biopsies using a sandwich-type ELISA. The concentration of IgA was significantly (P = 0.025) decreased in the ileum of patients with CUC (N = 24) in comparison to normal ileum (N = 10). The number of mucosal IgA-containing mononuclear cells (MNC) was also determined using an avidin-biotin-immunoperoxidase technique on paraffin-embedded ileal sections. Although reduced, the number of positive cells and their distribution was not significantly different in the ileum of patients with CUC (N = 20) when compared to normal ileum (N = 10). We suggest that decreased mucosal IgA levels are a panintestinal condition in CUC and that this is a primary alteration rather than a secondary response to the inflammatory process. Considering the role of IgA, we propose that decreased mucosal IgA levels in CUC may predispose to the disease by a reduction of the immune-mediated exclusion mechanism and/or by an impairment of the down-regulation of the inflammatory response.

[Surgical therapy of short bowel syndrome]. / Chirurgische Therapie des Kurzdarmsyndroms.

Advances in medical and surgical technique and the development of home parenteral nutrition have led to an increasing number of patients with short-bowel syndrome. Many patients could benefit from definite surgical therapy as long-term parenteral nutrition besides being expensive frequently causes severe complications. Various techniques to prolongate intestinal transit and increase the absorptive area of the remaining small bowel have been experimentally developed and some have been successfully employed in humans. The recent discovery of new potent immunosuppressive agents has initiated clinical endeavours at intestinal transplantation. The various techniques for the surgical therapy of short-bowel syndrome with their indications and potential risks are reviewed.

Functional impairment of enteric smooth muscle and nerves caused by chronic intestinal allograft rejection regresses after FK506 rescue.

We have previously demonstrated that subclinical chronic rejection (CR) induces structural and functional alterations in enteric smooth muscle and nerves in a rat model of small intestinal transplantation. This study was designed to investigate the effect of prolonged FK506 rescue therapy on these sequelae of CR. Immunohistochemistry of BrdU-labeled muscle cells demonstrated that active proliferation of intestinal smooth muscle caused by CR was successfully aborted by FK506 rescue therapy after a period of 30 days (control = 0.14 +/- 0.09; CR = 30.4 +/- 1.73; rescue = 2.4 +/- 0.63 cells/jejunal cross-section, P < 0.01). However, FK506 did not reverse the already established increase in muscular thickness (control = 92 +/- 2.4; CR = 193 +/- 10.6; rescue = 188 +/- 8.1 microns) due to CR. Bethanechol stimulated circular muscle contractility was improved markedly with rescue therapy (maximal contractile force reached 39.5% of control values in CR grafts and 68.8% after rescue). Rescue therapy did not reverse the loss of NADPH-diaphorase positive myenteric ganglia (control = 37 +/- 1.4; CR = 28 +/- 2.9; rescue = 23 +/- 1.7 ganglia/cross-section). Despite the persistent loss of ganglia, inhibitory junction potentials (IJPs) improved significantly returning to control values with FK506 (control = 10 +/- 0.5; CR = 5 +/- 0.3; CR rescue = 10 +/- 0.7 mV; IJPs recorded at 1 pulse/150V/0.75 ms). Although structural changes in enteric smooth muscle and myenteric neurons induced by CR were not reversed, the progression of subclinical CR can be effectively curbed by FK506 rescue therapy. The improvement in muscular mechanics and inhibitory neural innervation is probably due to the cessation of infiltrating immunocytes and sprouting of remaining myenteric nerves.