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Collateral vessel growth is a physiological process that is not equally pronounced in all people. After the development of a haemodynamically relevant stenosis in vascular systems, blood flow is directed through a collateral circulation to supply ischaemic tissue. This collateral circulation exists on the capillary level and by definition, is not composed of real new vessels. Postnatal vasculogenesis (true neovascularisation) occurs in the adult organism in tumour vascularisation, wound healing, in the endometrium, and in the context of chronic diseases such as rheumatoid arthritis and psoriasis. Reopening of the occluded vessel or use of artificial bypass grafts are the most attractive therapeutic approaches for treating peripheral arterial and coronary artery disease. These strategies have been exhausted in many patients; therefore augmentation of arteriogenesis can be more useful. Arteriogenesis, the promotion of natural collateral growth, is a hot topic in vascular research. Monocytes play a key role in arteriogenesis by "homing" to areas of collateral vessel growth and locally secrete multiple essential growth factors. Furthermore, stem cells of different origins, endothelial progenitor cells or mononuclear cells are currently being used to promote vessel growth. Also, the application of growth factors such as VEGF, MCP-1, GM-CSF have been already used in clinical trials. This review article describes the physiology and pathophysiology of vascular stenoses and their compensation mechanisms. The review also gives an overview of current treatment approaches and new strategies for non-operable PAD patients. The article presents the current cell and growth factor-related studies, as well as results of balloon dilatation and stent implantation or bypass surgery studies for improvement of revascularisation., (Georg Thieme Verlag KG Stuttgart · New York.)

According to the present experiences, the new videoendoscopic vascular instrument systems have fulfilled the basic requirements for performing videoendoscopic aortoiliac surgery. The animal studies (n = 25) showed clearly, that the piglet is a reproducible and favourable model to acquire the basic surgical techniques for videoendoscopic aortoiliac surgery, since its retroperitoneal anatomy is similar to that of humans. The transabdominal-retroperitoneal approach on human cadavers (n = 6) was soon abandoned, since particularly in obese cases it caused burdensome sliding of the intestine into the operative field adjacent to the renal vessels. The intensive investigations on human cadavers (n = 20) has meanwhile allowed us to constantly expose the aorta above the inferior mesenteric artery up to the left renal vessels without the need to sacrifice the inferior mesenteric artery (total operating time: 3-4.5 hours, aortic reconstruction averagely 42 minutes). The prolonged operating time during the extraperitoneal approach, especially in case of accidental tearing of the retroperitoneum has led us to evaluate the transabdominal paracolic approach (n = 6). This procedure with right-sided positioning of the patient offers a broad operating area and retains the intestine in the right side of the abdomen throughout, thus reducing the operating time in our initial 6 cases to a mean of 2.9 hours (range: 2.5-3.5 hours). As to our limited clinical experience and in accordance to other surgical groups the video assisted aortoiliac surgery (n = 12) by performing a small abdominal incision for the aortic anastomosis under direct vision seems to be an alternative procedure to the total videoendoscopic aortoiliac surgery (n = 7). Further experimental research, consistent development and refinement of videoendoscopic vascular instruments and prospective evaluation of the different videoendoscopic approaches to the aortoiliac vessels are necessary to evaluate the use of the videoendoscopic surgical technique, to clarify its advantages and to probably generalize the procedure in the near future.

The fact that operative lethality and other typical postoperative complications following surgical treatment of aortoiliac atherosclerotic disease are mainly related to the surgical trauma (derived from the extensive abdominal incision and dissection), but not to the classical arterial reconstruction itself, has led us to develop a videoendoscopic aortoiliacal surgical method which is supposed to diminish the potential postoperative complications. Thus, a new endoscopic instrument set for vascular surgery has been developed in close cooperation with Aesculap AG Tuttlingen, Germany. After evaluating the basic techniques of videoendoscopic patching and end-to-side anastomosis with the newly designed instruments on a training model (n = 50), the feasibility of videoendoscopic vascular surgery on aortoiliacal vessels was tried out on human corpses (n = 8). The positive results of the initial survey have finally encouraged us to conduct our first series of animal studies on piglets (n = 25). The investigation regarding ultrasonically monitored blood flow in the femoral arteries after videoendoscopic aortofemoral bypass grafting and other systemic, hemodynamic parameters showed positive results. No complications were encountered in any of the standardized animal studies. Favorable activity levels were recorded. Meanwhile we have performed 5 extraperitoneal videoendoscopic aortofemoral artery bypasses in patients with aortoiliac occlusive diseases. One patient in whom we had occluded the inferior mesenteric artery died due to an ischaemic colitis. The other patients had an uneventful postoperative course. The videoendoscopic vascular procedures were carried out according to the rules of conventional vascular surgery. Nevertheless, further experimental research and development of endoscopic instruments have yet to be done, to optimize the new surgical method and to clarify the advantages of videoendoscopic vascular surgery.

Although laparoscopic techniques in gastric surgery have become an important part of upper gastrointestinal surgery, they are mainly utilized for organ preserving procedures. A standardized technique for laparoscopic gastrectomy has not yet been described in detail. The purpose of this study was to develop a standardized technique for laparoscopic gastrectomy with reconstruction by a stapled termino-lateral esophago-je-junostomy and Roux-en-Y-anastomosis in a cadaver model. The resected stomach was removed through an enlarged trocar incision. The described technique has been successfully performed in one patient with early gastric cancer.

The clinical and long-term results encountered from July 1983 to December 1992 are subject of this study. Contrary to other (transanal and transabdominal) surgical treatments the endorectal system permits therapeutic local excisions of large, rectal adenomas and early rectal carcinomas of the "low-risk" type within the entire rectum with minimal morbidity. A superior or comparable rate of adenoma recurrence (4.8%, n = 228) as well as a more favourable operative result (complication rate 3.9%; lethality 0.6%; n = 348) can be achieved with the transanal endoscopic microsurgery. Under palliative conditions, transanal endoscopic surgery is more effective than other conservative treatments in cases of circumscribed, non-stenotic carcinomas of the rectum. Thorough surgical training is required in order to successfully practice transanal endoscopic surgery.

In order to avoid the perioperative complications following conventional surgical treatment of aortoiliac atherosclerotic occlusive disease, taking advantage of the generally favourable postoperative recovery after endoscopic surgery, a new concept of videoendoscopic vascular surgery and new instruments have been developed. Thus a standardized study on human cadavers and piglets was performed successfully finally enabling us to carry out two aortobifemoral arterial bypasses on two patients with iliac occlusive diseases. Even though it was possible to perform the endoscopic vascular method according to the rules of conventional vascular surgery, further experimental research and refinement of endoscopic instruments are still needed to optimize the new surgical method.

During the period March 3, 1992 to September 30, 1993 36 video-assisted thoracoscopic operations were performed at the Surgical Department of the University of Cologne. In 12 cases wedge resection of peripheral pulmonary nodules were carried out. Two of the patients underwent video-assisted thoracoscopic lobectomy of the left lower lobe due to peripheral primary bronchogenic carcinoma. In 6 cases biopsy of the lung or pleura was undertaken. Further indications were partial pleurectomy and resection of blebs (n = 12). Pleural effusion was drained under thoracoscopic vision twice. No intraoperative complications occurred. Two patients proceeded to thoracotomy after persistence of pneumothorax following thoracoscopic pleurectomy. The postoperative course of the remaining patients was uneventful and was especially characterized by the reduction in pain and disability. In accordance to the experience of other authors we believe that thoracoscopic surgery is a method with a promising future. Further investigations have to evaluate indications, different techniques, and long term results.

Minimal invasive surgery has become an important part of surgical therapy of non-parasitic cysts of the liver. At the moment there exist only a few but in all cases positive experiences with the laparoscopic unroofing of liver cysts. Until now we treated 3 patients with non-parasitic liver cysts by means of this method. In all cases we had no intra- or postoperative complications and the average hospital stay was 5 days. In agreement with other authors we think that laparoscopic unroofing of non-parasitic liver cysts is a method with promising future. The necessity of an intraoperative cholangiography in case of a bile leak respectively recurrence prophylaxis by means of an omentum major plastic will be decided by further clinical investigation.

Laparoscopic methods are becoming increasingly popular in surgery. In the course of a review concerning laparoscopic appendectomy undertaken up to 31 December 1993 all publications were evaluated by computer-assisted research. Out of a total of 90 publications only 14 deal with the comparison of the laparoscopic versus open appendectomy. Two prospective randomized studies are published. Because of the low number of patients the evaluation of the laparoscopic method is not yet definite.

While classical inguinal hernia repair has recently been brought up for discussions among surgeons, at present various modified techniques are being reintroduced in general surgery. Surgical hernia repair techniques which partly are known since several decades are being carried out laparoscopically since 1989. Between August 1992 and June 1993, the authors performed 52 laparoscopic inguinal hernia repairs using the preperitoneal placement of nonresorbable mesh. There were no intraoperative complications. Merely one patient had an abdominal wall hematoma at the site of a trocar which resolved spontaneously. All patients have been followed up for 3-13 months. To date, all postoperative check ups revealed no recurrences, testicular atrophy or paresthesia. Even though little can yet be said regarding long-term results especially about recurrences, laparoscopic preperitoneal hernia repair seems to be a promising surgical procedure concerning early postoperative results.

Low precision of transanal techniques, their limited area of application and high rate of complications of extensive surgical techniques led to the development of an endoscopic surgical system. Its main indication is the removal of broad based adenomas and early rectal cancers. Further indications are palliative excisions of advanced cancers. From July 1983 till December 1990 the endoscopic system has been employed on 233 patients. The total sum of operations raised to 251 cases due to recurrences and new tumour formations. The overall crude 5 year survival with merely local removal of rectal cancer was 67% for early rectal carcinoma patients and 75% for patients with pT2 carcinomas. Early postoperative complications consisted of 5 intraperitoneal perforations, 4 recto-vaginal fistulas and 4 haemorrhages (complication rate 5.2%). There were 2 postoperative deaths due to cardiopulmonary failure (clinical lethality 0.8%). The overall recurrence rate of adenomas was 4.9%. In accordance with the selection criterias of other authors, our selection criteria for curative local excisions of rectal cancers enclose tumour diameter less than 4 cm, pT1 carcinomas, low grade malignancy and tumour free margins of locally excised specimen.

Resection of the pancreas due to carcinoma represents with an operative mortality of 3.5% and three-year-survival of 15% an operative strategy, which should be carried out as a therapy of choice only on selected patients with an early cancer stage (ex. T1). But no other treatment offers the chance of long-time survival and curation. There seems to be no influence of operative therapy on patient prognosis in advanced cancer stages. In these cases, palliative treatment (ex. biliodigestive anastomosis or transcutaneous biliary drainage) are methods of choice. A main palliative aspect should be a painless patient. This can be achieved by oral or i.v. medication and/or chemical neurolysis of plexus coeliacus.

Two groups of 41 patients each who had undergone rectal resection or excision were questioned about the quality of their life an average of 4.3 or 3.8 years, respectively, after the operation. Three different measurements were obtained (Karnofsky, Grogono and Spitzer indexes). In addition, the patients provided a subjective estimate of the quality of their life. The quality of life was significantly better after resection than after excision, most clearly so according to the Grogono index, and this was also reflected in the patients' personal assessment. In males rectal excision frequently resulted in inferiority feelings, depression and disorders of sexual activity. Females found it easier to cope: they showed only minor differences in quality of life between resection and excision. Irrigation proved to be the best means of stoma care as far as quality of life was concerned.

Surgery of the lower third of the rectum can be done without difficulty through the anus using an endoscopical approach. Polyps or tumors located in the upper two thirds of the rectum can be removed using the Mason or Kraske procedure, or by the transabdominal approach. A new endoscopic technique has been developed with the aim, to allow surgery in the whole rectum through the anus. The rectum is being dilated by mechanical means and air insufflation. An oblique angle stereoscopic endoscope as well as modified surgical instruments are used. In animals 47 excisions of mucosa were done, and the incisions were closed by continuous suture. Application of this technique in a clinical setting is planned.