Optimal combined proton-photon therapy schemes based on the standard BED model.

This paper investigates the potential of combined proton-photon therapy schemes in radiation oncology, with a special emphasis on fractionation. Several combined modality models, with and without fractionation, are discussed, and conditions under which combined modality treatments are of added value are demonstrated analytically and numerically. The combined modality optimal fractionation problem with multiple normal tissues is formulated based on the biologically effective dose (BED) model and tested on real patient data. Results indicate that for several patients a combined modality treatment gives better results in terms of biological dose (up to [Formula: see text] improvement) than single modality proton treatments. For several other patients, a combined modality treatment is found that offers an alternative to the optimal single modality proton treatment, being only marginally worse but using significantly fewer proton fractions, putting less pressure on the limited availability of proton slots. Overall, these results indicate that combined modality treatments can be a viable option, which is expected to become more important as proton therapy centers are spreading but the proton therapy price tag remains high.

Influence of inguinal hernia mesh repair on testicular flow and sperm autoimmunity.

BACKGROUND: The incidence of infertility caused by the mesh inguinal hernia repair is not known. The aim of this study was to determine circulation and immunological testicular disorders after inguinal hernia mesh repair which can be related with infertility. METHODS: From February 2010 to December 2010, 43 male patients who underwent inguinal hernia mesh repair were included in a prospective study. Testicular, capsular and intratesticular arterial flow dynamics were measured by Color Doppler ultrasound before the operation, in early and late postoperative period. The antisperm antibodies were analyzed before hernia repair and 5 months after. RESULTS: The difference between patients who underwent laparoscopic (Group I) and anterior open tension-free hernia repair (Group II) in age, duration of symptoms and hernia characteristics were not significant. Statistically significant differences were found in peak-systolic and end-diastolic velocity in testicular and intratesticular arteries in Group II and in peak-systolic velocity on all levels in Group I. Only Group I had significant differences in resistive index of intratesticular arteries. All the values returned to basal in late postoperative period except testicular peak-systolic velocity in Group I which stayed in normal range. Wilcox matched pair test showed significant difference between preoperative and late postoperative measurements of the antisperm antibodies only in Group II, but it was within normal range in all cases. CONCLUSIONS: Inguinal hernia mesh repair do not have clinically significant influence on testicular flow and immunological response.

Management of cement vertebroplasty in the treatment of vertebral hemangioma.

BACKGROUND: The vertebral hemangiomas are benign vascular lesions occurring in spine. Although uncommon, symptomatic vertebral hemangiomas can be painful and can limit daily activities. A number of methods have been used in the treatment of symptomatic and aggressive vertebral hemangioma, but none of them is optimal. Treatment with cement vertebroplasty showed very good results. This study aims to illustrate the validity of the treatment with cement vertebroplasty in patients with painful vertebral hemangiomas. PATIENTS AND METHODS: From January 2000 to January 2007, 24 patients were treated by percutaneous vertebroplasty because of hemangioma: 16 thoracic, 8 lumbar. There were 11 males and 13 females. The average age at the time of surgery was 48 years. All the patients complained of a pain syndrome resistant to continuing medication. All patients underwent X-ray examination, CT-scan and MR of the involved level preoperatively. A unipedicular approach under fluoroscopic guidance has been performed in all patients. All procedures have been carried out under the local anesthesia. The mean follow-up was 5.8 years. RESULTS: In all the patients a successful outcome has been observed with a complete resolution of pain symptom. Extravertebral vascular cement leakage has been observed in 3 patients, without any clinical radicular syndrome onset due to the epidural diffusion. Clinical and radiological follow-up showed stability of the treatment and absence of pain in all patients. CONCLUSION: Percutaneous treatment with vertebroplasty for symptomatic vertebral hemangiomas is a valuable, less-invasive, and a quick method that allows a complete and enduring resolution of the painful vertebral symptoms without findings of the vertebral body's fracture.

How to prevent lateral thermal damage to tissue using the harmonic scalpel: experimental study on pig small intestine and abdominal wall.

INTRODUCTION: When using a harmonic scalpel, the lower amount of energy that is transduced to the tissue reduces the chance of lateral thermal damage. METHODS: Pigs (weight: 40 kg) were used as the experimental model. After anesthesia, tissue was coagulated using different application regimens for each group. The width of tissue necrosis was measured from the point of incision by the harmonic scalpel. RESULTS: The pig abdominal tissues suffered mean thermal damage of 0.0825 (output power 3) and 0.2969 mm (output power 5) when used for 5 s; at 10 s these values were 0.3850 and 0.4793 mm, respectively. In a third experimental condition, with 10 s of application broken down into 2 parts of 5 s with a 5-second pause in-between, these values were 0.1876 and 0.2013 mm, respectively. The small intestine tissues suffered mean thermal damage of 0.1302 (output power 3) and 0.1771 mm (output power 5) at a duration of 5 s. After 10 s of application, these values changed to 0.2655 (output power 3) and 0.2983 mm (output power 5). In the third condition (activity for 5 s, pause for 5 s, activity for 5 s), they were 0.2011 and 0.2258 mm, respectively. CONCLUSION: Coagulation necrosis is bigger if the usage is continuous rather than if it is disconnected/reconnected.

Lateral thermal damage to rat abdominal wall after harmonic scalpel application.

BACKGROUND: Use of the Harmonic Scalpel transduces a lower amount of energy to tissues, thereby limiting the potential for lateral thermal damage and deep penetration because only low temperatures are reached. The working principle of the Harmonic Scalpel is the transformation of electric power into the longitudinal mechanical movement of the instrument tip. This study aimed to determine the effects from varying durations of Harmonic Scalpel application on the experimental model of rat abdominal wall without skin. METHODS: After the rats had been anesthetized, and a laparotomy was performed. The Harmonic Scalpel shears were used on the muscular part of the abdominal wall without skin. Different durations of output power 3 were applied: a single 5-s application, a single 10-s application, and a regimen of two sequential 5-s applications. Each animal in each group of 10 received five individual activations, after which the animals were killed. Tissue samples were fixed and embedded in paraffin before sections were taken and stained. Using light microscopy and morphometric imaging analysis, the width of tissue lateral thermal damage was measured from the point of Harmonic Scalpel incision. RESULTS: The rat abdominal wall showed lateral thermal damage over a mean width of 0.0522 +/- 0.0097 mm after a 5-s Harmonic Scalpel application, a damage width of 0.1544 +/- 0.0419 mm after a 10-s application, and a damage width of 0.1020 +/- 0.0430 mm after a 5-s application followed by 5 s of inactivity and another 5 s of activity. These differences in thermal damage width between all the groups are statistically significant. CONCLUSIONS: The findings lead to the conclusion that tissue lateral thermal damage after Harmonic Scalpel application at standard output power is greater when a longer sustained period of application is used. Lateral thermal damage also is greater if the Harmonic Scalpel application time is continuous rather than of the same total duration with a brief midpoint interruption.

Technique and survival after laparoscopically assisted right hemicolectomy.

BACKGROUND: The role of laparoscopic colon resection in the management of colon cancer is still controversial. In this article, the surgical strategy and techniques are described, with further consideration of the oncologically relevant aspects. METHODS: Between March 1993 and July 2003, we performed laparoscopic right hemicolectomy in 56 patients with right colon carcinoma. Average age was 74.5 years (range, 17-92). We performed a standardized surgical procedure that included mobilization from the vascularized mesenteric bridges with a window technique, transection of the ileocolic lymphovascular pedicle, and lateral and proximal mobilization of the ileocecum, ascending colon, right flexure, and proximale transversum. After enlargement of one of the trocar incisions the exteriorized colon was resected and an extracorporeal anastomosis was performed in the standard manner. RESULTS: There were no conversions to open. The mean operating time was 119 +/- 38 min, the mean length of resected colon was 27.8 +/- 4.48 cm, and the average width of the clear margins was 6.8 +/- 5.3 cm. One patient died. Lymph nodes were positive in 21 patients. The 5-year survival rate in the 48 patients who were operated on with curative intent was 75%. We have had two local recurrences. The overall 5-year mortality-free fraction was 63%. Cox multivariate analysis showed that the mortality-prognostic factors were tumor stage and length of resected colon, whereas Kaplan-Meier analysis showed that the mortality-prognostic factors were positive lymph nodes and tumor stage. CONCLUSIONS: Our results show that laparoscopic right hemicolectomy for colon cancer can be performed safely. Complications and recurrence rates are comparable to those for left-sided laparoscopic and open procedures. Therefore, we recommend this procedure as the method of choice. Laparoscopically treated patients with stage II and stage III disease have almost the same cumulative rate of survival.

[Bile duct injuries in laparoscopic cholecystectomy]. / Ozljede zucnih vodova pri laparoskopskoj kolecistektomiji.

Bile duct injuries are the most serious complications of laparoscopic cholecystectomy. Although the overall complications rate in laparoscopic cholecystectomy is significantly lower than in open cholecystectomy, bile duct injuries are more frequent. In this article we analyzed why and how they occur and if their prevention was possible. From May 1992 to May 1999, laparoscopic cholecystectomy was performed in 5651 patients by 17 surgeons and residents, with different experience but similar operative technique. In this period nine (0.16%) bile duct injuries occurred. Injuries were caused by seven operators. Number of operations by single surgeon before injury varied from 8 to 1477. Three patients with uncomplicated chronic cholecystitis had puncture or small bile duct laceration. Complete transection of main bile duct occurred in three patients and in one transection of right hepatic duct. The operative findings in two of them were acute cholecystitis, one had fibrosis in the triangle of Calot and one uncomplicated chronic cholecystitis. Bile duct strictures were found in two patients. Both had fibrosis in the triangle of Calot and in hepatic port. Dangerous pathologic findings were the main cause of injuries in 5 and inadequate surgical technique in 4 patients. In our opinion the education, critical state and experience are of main importance in avoidance and prevention of bile duct injures. We also plead for selective use of intraoperative cholangiography. In our opinion the intraoperative cholangiography has to be performed in all cases where the anatomy of the triangle of Calot is not clear.

[Less invasive laparoscopic cholecystectomy: initial experience and literature review]. / Manje invazivna laparoskopska kolecistektomija: nasa pocetna iskustva i pregled literature.

Laparoscopic cholecystectomy using the 5 and 10 mm caliber instrument is still a gold standard for surgical treatment of the gallstone disease. Today it is possible to perform this operation with a less invasive manner, using the fine caliber instruments, whose diameter is under 5 mm. According to published data, less invasive laparoscopic cholecystectomy does not have a higher complication rate, and other parameters are very similar or even better, specially the cosmetic outcome. In this article with small patient number we confirmed better cosmetic outcome, described different operation techniques and warned about the shortcomings. A greater number of patients and randomized study is indispensable for better technique analysis.

[Comparison of the results of laparoscopic cholecystectomy preformed in the usual way and with a lesser number of trocars]. / Usporedba rezultata laparoskopskih kolecistektomija ucinjenih na uobicajeni nacin i onih s manjim brojem troakara.

Laparoscopic surgery is a part of the minimally invasive surgery. Its aim is to make on operation as valuable as the open one, or even more, with a smaller invasion or injury of the body. With the instruments improvement the operation would be possible without any remarkable organism injury. On the other hand, modifications of the operation techniques lead to progress. European technique of laparoscopic cholecystectomy using four trocars has changed. Procedures are performed with one trocar less. Two groups of two hundred patients each have undergone laparoscopic cholecystectomy. The operation in the first group was performed using four, and in the second group using three trocars. The aim of the investigation was to compare these two methods of laparoscopic cholecystectomy. The results analysis showed that laparoscopic cholecystectomy using three trocars did not cause either a higher complication rate, prolonged average operation time or longer duration of hospitalisation. The analgesics consumption was lower, sick-leaves were shorter, with smaller total costs, and cosmetic effect was better.

A new bipolar hook for endoscopic surgery.

This article presents a new bipolar hook for endoscopic surgery. With this instrument monopolar and bipolar current can be used. The advantage of this new instrument is the possibility of using a bipolar current, which is safer than using the monopolar current. The technical details and usage instructions are discussed.

[Reintegration of health services in the Danube area of the Croatian health care system: introduction of laparoscopic surgery in the Vukovar General Hospital]. / Reintegracija zdravstva u Podunavlju u hrvatski zdravstveni sustav: uvodenje laparoskopske kirurgije u opcoj bolnici Vukovar.

After six years of occupation, in the second half of 1997 started the reintegration of the Danube region in the Croatian health care system. Introducing of the laparoscopic surgery in Vukovar General Hospital has been presented in this article. A part of the laparoscopic equipment and reusable instruments was a gift of the Croatian Institute for Health Insurance, and some equipment and instruments were bought. Until now, 170,000 HRK has been spent for laparoscopic surgery. The first laparoscopic operations--laparoscopic cholecystectomies in our hospital were performed on June 25, 1998. From October 1, 1998, laparoscopic operations have been regularly done. Until December 24, 1998, laparoscopic cholecystectomies, hernioplasties, appendectomies and diagnostic laparoscopies were performed. The total number of laparoscopically operated patients is 23. We did not have serious intra or postoperative complications. On November 20-21, the 10th postgraduate course on laparoscopic cholecystectomy was organized in our hospital. In a relatively short time and specific circumstances, laparoscopic surgery has become a standard surgical method in Vukovar General Hospital.

[5 years' laparoscopic surgery in Croatia]. / Pet godina laparoskopske kirurgije u Hrvatskoj.

Under the patronage of the Croatian Endoscopic Society, in October 1995 and October 1997, data from the Croatian surgery departments with laparoscopic surgery have been collected. The aim has been to evaluate the situation and development of endoscopic surgery in Croatia. The types and number of the procedures increased during the entire period. The total number of procedures is 29,349. The biggest part of that number, 25,889 (88.2%), were laparoscopic cholecystectomies. The next most frequent operations were laparoscopic hernioplasties and appendectomies. Many others laparoscopic operations were performed, too. The conversion and complication rate can be compared with the other authors' results. Endoscopic surgery in Croatia today is completely accepted and has become a part of digestive surgery in almost all surgical departments.

[High frequency current in endoscopic surgery and a new bipolar hook for endoscopic surgery]. / Visokofrekventna struja u endoskopskoj kirurgiji i nova bipolarna kukica za endoskopsku kirurgiju.

High frequency current is used in surgery for cutting the tissue and stopping bleeding. Its usage is more frequent in endoscopic than open surgery. "Polarity" (monopolar and bipolar) marks the number of the electrical poles on the application place. Monopolar current has been used more often. With its usage thermal injuries are possible: coagulation outside of the laparoscopic view, direct coupling, capacitive coupling, sparking, skin combustion, activity on the heart rhythm. Because of these complications, the bipolar current is more and more in usage, which reduces the number of complications or avoids them completely. Many bipolar instruments are available today. Bipolar hook for endoscopic surgery is a new instrument which unites the good characteristics of the hook and bipolar current.

Laparoscopic treatment of nonparasitic cysts of spleen and liver.

Laparoscopic treatments of nonparasitic splenic and liver cysts in the period between March 1993 and April 1995 have been reported: partial decapsulation-fenestration and evacuation of a splenic pseudocyst in one patient, fenestration of large congenital liver cysts with total excision of a few smaller liver cysts in two patients and two unsuccessful treatments of splenic cysts. After successful laparoscopic procedures the patients experienced immediate and complete relief of the symptoms. Two years after the splenic cyst procedure and 6 months after the liver cyst operation, the patients remained free of the symptoms, and complete absence of the cysts was confirmed by computerized tomography scans. Laparoscopic fenestration of nonparasitic splenic and liver cysts with total excision of smaller liver cysts is a simple and safe surgical method with lower morbidity and a quick return to normal activity.

[Comparison of open and laparoscopic appendectomy]. / Usporedba otvorene i laparoskopske apendektomije.

The first laparoscopic appendectomy was performed by Senn in 1982. Since then, the dilemmas about the validity of this operation in relation to open operation have persisted. Many authors presented the technique modifications and results that are very different. The retrospective results, cost, duration of hospital stay and postoperative recovery analyses for fifty patients in each group were done in this study. Laparoscopic operations were done by "two-handed" technique and in different ways of appendix and mesoappendix closing and cutting. Endoscopic linear cutters were used in the second part of the study. When comparing parameters, laparoscopic operation in relation to open operation is equally safe; quicker; with less postoperative pain; with less wound infections rate; with shorter hospital stay; with less staff time involved; with faster recovery and return to work; more expensive; with better cosmetic effect. In conclusion, laparoscopic appendectomy is better, although more expensive, than open operation, so it should be recommended.

Laparoscopic cholecystectomy following abdominal surgery of the lower part of abdomen.

In this prospective study, laparoscopic cholecystectomy was performed in patients with previous abdominal surgery of the lower part of abdomen. According to authors experience, the usual method of 'blind' beginning of the laparoscopic procedure, with safety tests, is a safe and reliable method to start the laparoscopic procedure, even in these patients. This method does not carry a higher risk of intra-abdominal injury.

Laparoscopic cholecystectomy: results after 1000 procedures.

From May 1992, when the first laparoscopic cholecystectomy was performed at University Department of Surgery, Sveti Duh General Hospital, till October 1994, the authors performed more than 1000 procedures. Laparoscopic approach was successfully used in 965 (96.5%) patients. Thirty-five (3.5%) cases were converted to open surgery. Dangerous anatomy, some technical problems and perioperative bleeding were the most often reasons for conversion. Further, liver metastases and perioperatively recognized common bile duct lesion necessitated conversion in one case each. In total, there were 18 (1.8%) abdominal complications. Common bile duct lesion, postoperative common bile duct stricture and duodenal perforation occurred in one patient each. Major bleeding was present in eight and bile leak in seven patients. The mean duration of hospitalization was 2.8 days. Analyses of the results show laparoscopic cholecystectomy to be safe procedure with low perioperative and postoperative complications.