Intraoperative irradiation delays anastomotic repair in rat colon

Lumen-apposing metal stent through the meshes of duodenal metal stents for palliation of malignant jaundice

Background and study aims  Endoscopic retrograde cholangiopancreatography (ERCP) is the gold standard procedure for malignant jaundice palliation; however, it can be challenging when a duodenal self-expandable metal stent (SEMS) is already in place. Patients and methods  The primary aim of our study was to evaluate the technical feasibility of the placement of a lumen apposing metal stent (LAMS) through the mesh (TTM) of duodenal stents. The secondary aims were to evaluate clinical outcomes and adverse events (AEs) related to the procedures. Results  Data from 23 patients (11 F and 12 M; mean age: 69.5 ± 11 years old) were collected. In 17 patients (73.9 %) TTM LAMS placement was performed as first intention, while in six patients (26.1 %) it was performed after a failed ERCP. Thirteen patients (56.5 %) underwent the procedure due to advanced pancreatic head neoplasia. One technical failure was experienced (4.3 %). The TTM LAMS placement led to a significant decrease in the serum levels of bilirubin, ALP, GGT, WBC and CRP. No cases of duodenal SEMS occlusion occurred and no other AEs were observed during the follow-up. Conclusions  Concomitant malignant duodenal and biliary obstruction is a challenging condition. Palliation of jaundice using TTM LAMS in patients already treated with duodenal stent is associated to promising technical and clinical outcomes.

Morphologic change of rectosigmoid colon using belly board and distended bladder protocol

Purpose

This study investigates morphologic change of the rectosigmoid colon using a belly board in prone position and distended bladder in patients with rectal cancer. We evaluate the possibility of excluding the proximal margin of anastomosis from the radiation field by straightening the rectosigmoid colon.

Materials and Methods

Nineteen patients who received preoperative radiotherapy between 2006 and 2009 underwent simulation in a prone position (group A). These patients were compared to 19 patients treated using a belly board in prone position and a distended bladder protocol (group B). Rectosigmoid colon in the pelvic cavity was delineated on planning computed tomography (CT) images. A total dose of 45 Gy was planned for the whole pelvic field with superior margin of the sacral promontory. The volume and redundancy of rectosigmoid colon was assessed.

Results

Patients in group B had straighter rectosigmoid colons than those in group A (no redundancy; group A vs. group B, 10% vs. 42%; p = 0.03). The volume of rectosigmoid colon in the radiation field was significantly larger in group A (56.7 vs. 49.1 mL; p = 0.009). In dose volume histogram analysis, the mean irradiated volume was lower in patients in group B (V45 27.2 vs. 18.2 mL; p = 0.004). In Pearson correlation coefficient analysis, the in-field volume of rectosigmoid colon was significantly correlated with the bladder volume (R = 0.86, p = 0.003).

Conclusion

Use of a belly board and distended bladder protocol could contribute to exclusion of the proximal margin of anastomosis from the radiation field.

The effects of Pycnogenol(®) on colon anastomotic healing in rats given preoperative irradiation

Pycnogenol(®) has excellent radical scavenging properties and enhances the production of antioxidative enzymes which contributes to the anti-inflammatory effect of the extract. Irradiation delivered to the abdominal region, typically results in severe damage to the intestinal mucosa. The effects of ionizing radiation are mediated by the formation of free radicals through radiolysis. Irradiation has local effects on tissues. These local effects of irradiation on the bowel are believed to involve a two-stage process which includes both short and long term components. In our study we aimed to investigate the short term effects of Pycnogenol(®) on the healing of colon anastomoses in irradiated bowel. Sixty male Wistar-Albino rats were used in this study. There were three groups: Group I, control group (n = 20); group II which received preoperative irradiation (n = 20); group III which received per oral Pycnogenol(®) before irradiation (n = 20). Only segmeter colonic resection and anastomosis was performed to the control group (Group I). The other groups (Group II, III) underwent surgery on the 5th day after pelvic irradiation. On postoperative days 3 and 7, half of the rats in each group were sacrificed and then relaparotomy was performed. There was no statistical difference between groups with respect to biochemical parameters. Bursting pressure was significantly higher in the Control and Group III compared with the Group II. In conclusion, the present study showed that preoperative irradiation effect negatively on colonic anastomoses in rats by means of mechanical parameters and administration of Pycnogenol(®) preoperatively ameliorates this unfavorable effect.

Does long-course radiotherapy influence postoperative perineal morbidity after abdominoperineal resection of the rectum for cancer?

AIM

The aim of the study was to define risk factors for perineal wound complications after abdominoperineal resection (APR), with particular reference to preoperative radiotherapy.

METHOD

Patients undergoing APR at our institution between 1985 and 2009 were reviewed. Wound complications were classified according to the Center for Disease Control and Prevention classification of surgical site infection (SSI). Perineal complications were identified in patients who had preoperative long-course radiotherapy (Group 1) and those who had surgery alone (Group 2).

RESULTS

One hundred and fifty-seven patients met the inclusion criteria. Preoperative radiotherapy was performed in 68 (44.7%) patients (Group 1), and 89 (65.3%) patients (Group 2) underwent surgery alone. The overall rate of perineal wound complications was 14.8%. The wound infection rate was similar in each group (Group 1, 10/68, 14.7%; Group 2, 13/89, 14.9%; P = 0.9). An elevated BMI (>30) was the only factor correlated with perineal morbidity on univariate analysis (P = 0.01).

CONCLUSION

Preoperative radiotherapy does not influence perineal healing other than in patients with obesity.

Preoperative irradiation with 5 x 5 Gy in a murine isolated colon loop model does not cause anastomotic weakening after colon resection

INTRODUCTION

There are conflicting studies on the influence of fractionated preoperative 5 days of 5 Gy irradiation on tissue oxygenation and subsequent colonic anastomotic strength. To elucidate the effect of preoperative irradiation on anastomotic strength, an isolated colon loop model was developed.

METHODS

Male Wistar rats (n = 164) were randomly divided into three groups. One group remained untreated (control). In the other two groups, a loop of descending colon was exteriorized to create a hernia of the abdominal wall. After 4 weeks' recovery, this loop was locally irradiated with 5 x 5 Gy of gamma-rays or sham irradiated. One week after (sham-) irradiation, an anastomosis was performed in all groups. Tissue oxygenation (StO2) was determined with visible light spectroscopy. The animals were sacrificed 3 or 7 days after the operation and the anastomosis was tested for bursting pressure and breaking strength.

RESULTS

Irradiated rats showed significantly more weight loss (90% SD 4.3 of initial body weight vs. 96% SD 2.8, p < or = 0.05) and enteritis (18% vs. 5%, p = 0.013) compared to sham and control animals. StO2 was not influenced by irradiation and was not predictive for anastomotic strength. The control group showed significantly lower bursting pressure and breaking strength compared to (sham-) irradiated animals.

CONCLUSION

We developed a new isolated loop model for intermittent irradiation of the colon. Preoperative irradiation of the distal part of a colon anastomosis was successfully administered with acceptable side effects and did not cause reduced tissue oxygenation nor clinical signs of anastomotic weakening, nor objective reduction in bursting pressure and breaking strength.

The effect of preoperative radiotherapy on systemic collagen deposition and postoperative infective complications in rectal cancer patients

PURPOSE

Preoperative, high-dose radiotherapy for rectal cancer reduces local recurrence rates and improves overall survival. However, adverse effects in varying degrees include impaired wound healing and local infection. This study investigates the influence of preoperative, high-dose radiotherapy on subcutaneous accumulation of collagen in a primary rectal cancer group operated on with or without adjuvant radiotherapy.

METHODS

Forty-two eligible patients who underwent total mesorectal excision surgery with or without radiotherapy were included in the study. Polytetrafluoroethylene tubings were implanted in the arm ten days before surgery (three days before the start of radiotherapy). Implants were extracted the day before surgery. New implants were inserted before surgery and were extracted ten days after surgery. The hydroxyproline and proline contents of the implants were measured and the hydroxyproline/proline ratio was calculated as a measure for deposited collagen relative to protein. Blood loss, postoperative complications, and blood levels of hemoglobin, leukocytes, and albumin were recorded.

RESULTS

The two groups were similar in relation to Dukes stage, age, and body mass index. Infectious complications developed in 39 percent of patients after radiotherapy compared with 16 percent in the nonirradiated group. In the irradiated patients with infective complications we found a significant decrease in the hydroxyproline/proline ratio compared with that of irradiated patients without infections (P = 0.037). There was a significant decrease in the leukocyte count preoperatively and postoperatively in the irradiated group compared with surgery alone.

CONCLUSIONS

High-dose, short-term radiotherapy does not have a systemic effect on collagen accumulation, but a significant reduction is manifested in infected patients. Radiotherapy also impairs leukocyte production and increases the postoperative infective complication rate.

Improvement of colonic healing by preoperative rectal irrigation with short-chain fatty acids in rats given radiotherapy

BACKGROUND

We investigated the effect of preoperative rectal irrigation with short-chain fatty acids on irradiated colonic anastomosis in rats.

METHODS

Sixty male Wistar rats were divided into four groups. Group I (control group, n = 15) underwent left colon resection and primary anastomosis. Group II (Short-chain fatty acids pretreatment group, n = 15) had short-chain fatty acids rectal irrigation for five days preoperatively. Group III (preoperative radiotherapy group, n = 15) underwent irradiation to the whole pelvis eight and four days before the operation, for a total dose of 20 Gy. Group IV (preoperative radiotherapy group + short-chain fatty acids pretreatment group, n = 15) had rectal irrigation with short-chain fatty acids for five days after the second irradiation. Within each group, animals were anesthetized to assess the clinical, mechanical, histologic, and biochemical parameters of anastomotic healing on either the third or seventh postoperative days.

RESULTS

The mean bursting pressure was significantly low in Group III on Day 3 and was significantly high in Group IV on Day 7 (P = 0.001, P = 0.021). The burst occurred at the anastomoses in all animals tested on the third postoperative day, and outside of the anastomoses in all animals tested on the seventh postoperative day. The histologic parameters of anastomotic healing, such as epithelial regeneration and formation of granulation tissue, were significantly improved by use of preoperative rectal irrigation with short-chain fatty acids on Day 7. The amount of total and salt-soluble collagen concentrations significantly increased in Group IV compared with the control group on Day 3 (P = 0.008, P = 0.004).

CONCLUSION

Some mechanical and histologic aspects of colonic anastomotic healing can be adversely affected by preoperative radiotherapy, but rectal irrigation with short-chain fatty acids may improve anastomotic healing.

Efeitos da irradiação com raios-X em anastomoses colônicas: estudo estereológico experimental em ratos

OBJETIVO: Este estudo foi realizado para quantificar possíveis alterações na tensão de ruptura e na concentração de colágeno em anastomoses realizadas em cólon irradiado. MÉTODOS: Doze ratos Wistar foram submetidos a secção e anastomose do cólon, constituindo dois grupos: An (controle, n=7) e I+An (irradiado, n=5). O grupo An foi submetido apenas à cirurgia enquanto o grupo I+An recebeu dose única de irradiação (1096 cGy) 7 dias antes da operação. Todos foram sacrificados no sétimo dia pós-operatório, para verificação da tensão de ruptura da anastomose e quantificação do colágeno. A quantificação do colágeno foi feita por estereologia de cortes verticais. RESULTADOS: O grupo An apresentou valores superiores ao grupo I+An quando comparados a pressão de ruptura da anastomose (172 mm Hg X 60 mm Hg, p = 0,004) e o índice de colágeno (14,24 X 1,62, p = 0,004). No grupo An o local de ruptura do cólon ocorreu com maior freqüência na área perianastomótica, enquanto que no grupo I+An a ruptura ocorreu com maior freqüência na linha anastomótica (p = 0,007). CONCLUSÃO: A irradiação prejudicou a cicatrização anastomótica, conforme evidenciado pela diminuição da pressão de ruptura da anastomose e do índice de colágeno no grupo de animais irradiados.

A comparison in cosmetic outcome between per-operative interstitial breast implants and delayed interstitial breast implants after external beam radiotherapy

BACKGROUND AND PURPOSE

Interstitial implants for brachytherapy boost in the breast conserving therapy of breast cancer can be performed in two ways; implants during the tumor excision (per-operative implants) or after the external beam therapy (delayed interstitial implants). Differences in cosmetic outcome were investigated.

PATIENTS AND METHODS

Cosmetic results in 47 patients having a per-operative implant were compared to 123 patients having a delayed interstitial implant in a matched case-control study. Cosmesis was scored on a four-point-scale varying from 0 (excellent) to 3 (poor).

RESULTS

After mean follow-up of 63 months, three observers found no difference in cosmetic outcome between the two groups after adjustment for variables found to be related with cosmesis (difference in mean score 0.50, P=0.26). Implant volume at 100% isodose was not found to differ (P=0.084) between the per-operative group (mean 102 cm3, S.D. 34 cm3) and the delayed group (mean 93 cm3, S.D. 29 cm3).

CONCLUSIONS

Performing per-operative implants has not led to smaller implants. The method of performing brachytherapy does not result in marked differences in cosmetic outcome.

Effects of radiation damage on intestinal morphology

The current flow of papers on intestinal structure, radiation science, and intestinal radiation response is reflected in the contents of this review. Multiparameter findings and changes in compartments, cells, or subcellular structure all contribute to the overall profile of the response. The well-recognized changes in proliferation, vessels, and fibrogenesis are accompanied by alterations in other compartments, such as neuroendocrine or immune components of the intestinal wall. The responses at the molecular level, such as in levels of hormones, cytokines, or neurotransmitters, are of fundamental importance. The intestine responds to localized radiation, or to changes in other organs that influence its structure or function: some structural parameters respond differently to different radiation schedules. Apart from radiation conditions, factors affecting the outcome include the pathophysiology of the irradiated subject and accompanying treatment or intervention. More progress in understanding the overall responses is expected in the next few years.

Effects of early postoperative 5-fluorouracil and ageing on the healing capacity of experimental intestinal anastomoses

BACKGROUND

Results from a previous study suggested that advanced age does not affect early repair of experimental intestinal anastomoses. The present study aimed to establish whether anastomotic healing is impaired more easily in old animals by immediate postoperative chemotherapy.

METHODS

Young adult (2-3 months) and old (27-30 months) rats underwent resection and anastomosis of both ileum and colon. Within each age group, subgroups received intraperitoneal saline or 5-fluorouracil in a dose of 15 or 20 mg per kg per day from the day of operation onwards. After 7 days, anastomotic healing was assessed by wound strength and collagen deposition in the wound area.

RESULTS

No differences were found between young and old control groups. The higher dose of fluorouracil induced severe loss of strength with concomitant reduction of wound collagen, which was similar in both age groups (ileum: from 52(13) to 24(8) volume per cent in young animals and from 56(10) to 20(9) volume per cent in old animals; colon: from 58(10) to 37(18) volume per cent in young animals and from 65(5) to 30(17) volume per cent in old animals). The lower dose of fluorouracil induced a significantly greater loss of strength, measured as the bursting pressure, in the old animals (150(49) versus 201(59) mmHg in colon of young rats).

CONCLUSION

In this model early anastomotic repair in older animals proceeds normally under optimal conditions, but it is more easily disturbed in the presence of fluorouracil.

Immediate postoperative 5-FU does not decrease colonic anastomotic strength

BACKGROUND AND OBJECTIVES

The use of continuous infusion 5-Fluorouracil (5-FU) immediately after surgery may improve the adjuvant treatment of resected colon cancer and is the subject of a national phase III trial (Intergroup no. 0136). The aim was to determine the effect of continuous infusion 5-FU on the bursting pressure of a colon anastomosis.

METHODS

Twenty Lewis rats weighing approximately 300 g were subject to sigmoid colectomy and single-layer anastomosis. Ten rats received 5-FU continuously at 600 mg/m2 per day for 7 days; 10 rats served as controls. Ten days postoperatively, the rats were sacrificed and bursting pressure of the colon containing the anastomosis was determined.

RESULTS

No anastomotic leaks or intra-abdominal abscesses were identified. Burst pressure of the colon in controls (124+/-13 mm Hg; mean+/-SEM) was not significantly different from those animals receiving 5-FU (115+/-9, P > 0.05). The control rats gained weight (13+/-7 g), which is significantly different from the rats receiving 5-FU (-19+/-13, P=0.04).

CONCLUSIONS

Continuous infusion 5-FU postoperatively results in weight loss, but does not affect anastomotic bursting strength in rats. This evidence supports the safety of continuous infusion 5-FU postoperatively in humans.

Late effects of intraoperative radiation therapy in anastomotic rat colon

PURPOSE

to determine whether intraoperative radiotherapy causes long-term negative effects on the healing of colonic anastomoses in the rat.

METHODS AND MATERIALS

175 rats were divided into seven equal groups. One group served as sham-irradiated control group. In the others, following a colonic resection, 1 or 2 cm of the distal bowel limb was irradiated with a single dose of 10, 15, or 20 Gy (groups 10/1, 15/1, 20/1, 10/2, 15/2, and 20/2, respectively). Subsequently, an anastomosis was constructed. The animals were killed after 6 (n = 10 in each group) or 12 (n = 15) months. The abdomen was inspected for abnormalities and the colonic diameter was measured. The anastomotic segment was analyzed biochemically (hydroxyproline) and histologically.

RESULTS

During the experimental period, 1 rat (group 15/1) died because of anastomotic leakage and 3 others died from unknown causes. There was no difference in colonic diameter between groups. Altogether 17 rats developed an adenocarcinoma in the irradiated area: 11 of these had received a dose of 20 Gy. Histological observation indicated that fibrosis was present only in a limited number of animals, mostly after irradiation with a dose of 15 or 20 Gy. All anastomoses were functional and showed normal histology. The hydroxyproline content of the anastomotic segment was increased--with respect to the control group--only in the 20/2 group after 6 months. After 12 months, the hydroxyproline concentration in the (irradiated) segment distal to the anastomosis proper was higher in the 10/1 and 15/1 groups than in the control group. Otherwise, there were no differences between groups.

CONCLUSION

Intraoperative irradiation with a single dose of 10-20 Gy, delivered to the distal limb used for anastomotic construction, does not appear to constitute a threat to anastomotic integrity. Dose-related changes included formation of adenocarcinomas and fibrosis, but function and histology of the anastomosis proper remained unaffected.

Effects of preoperative fractionated irradiation on left colonic anastomoses in the rat

PURPOSE

Radiotherapy is frequently used as a (neo)adjuvant to surgery in colorectal cancer patients, and because such therapy could influence the integrity of the anastomosis, we decided to investigate the effect of preoperative irradiation on colonic anastomosis.

METHODS

Seventy-two male Wistar rats, weighing 200 to 348 g, were divided into three groups: a control group (I) underwent left colon resection and primary anastomosis (n = 20); a sham irradiated group (II, n = 20); a study group (III) that received fractionated irradiation to the whole pelvis (anterior-posterior pelvic field), for a total dose of 22 Gy, 5.5 Gy per fraction, on four consecutive days with linear accelerator (n = 32). Four days after irradiation, both Groups II and III underwent the same operation as performed in Group I. Within each group, one-half of the animals were anesthetized on the third postoperative day and one-half on the seventh postoperative day. Abdominal wound-healing, anastomotic complications, and anastomotic bursting pressure measurements were recorded. Following these measurements, the anastomotic segment was resected for hydroxyproline content and myeloperoxidase activity.

RESULTS

Irradiated animals had more pronounced weight loss during therapy. There were no differences with abdominal wound-healing, intraperitoneal adhesions, and anastomotic complications between groups. At days 3 and 7, mean bursting pressures of the anastomosis were determined at 36.5 and 208 mmHg in Group I, 34.5 and 228 mmHg in Group II, and 25 and 150 mmHg in Group III, respectively (P < 0.01 Group III vs. both Groups I and II on days 3 and 7). The burst occurred at the anastomosis in all animals tested on the third postoperative day and one in Group I (10 percent), none in Group II, and six in Group III (37.5 percent) on the seventh postoperative day. In addition, hydroxyproline content and myeloperoxidase activity was significantly lower in Group III.

CONCLUSION

Although preoperative fractionated irradiation significantly decreased the anastomotic bursting pressure and more burst occurred in the anastomotic line on postoperative day 7, the clinical outcome was similar among the groups.

Quantitation of angiogenesis in healing anastomoses of the rat colon

An accurate and reliable quantitation of angiogenesis is an essential requirement for a detailed study of new blood vessel growth during healing of colon anastomoses. In the present study we applied a computer-based digital image processing system for quantitative analysis of the anastomotic vascularization and perfusion. Rats underwent colonic resection (1 cm) followed by construction of an end-to-end anastomosis. The animals were killed 3 or 7 days after operation. The vascularization and perfusion were analysed in cyrostat sections using an anti-collagen type IV antibody and the fluorescent marker bisbenzimide H 33342, respectively. If compared with 3-day-old anastomoses, a significant increase in the median vascular and perfusion areas was found 7 days after operation. Within the same anastomosis, the vessel density and perfusion were lower in the central region than in the peripheral region of the wound. The present computerized digital image analysis system is a reliable technique that is suited for quantitative measurements of microvascular changes occurring in colon anastomoses during the first postoperative week.

Divergent patterns of matrix metalloproteinase activity during wound healing in ileum and colon of rats

BACKGROUND

Uncontrolled and increased extracellular matrix degradation during early anastomotic repair in the intestine may reduce wound strength increasing the risk of anastomotic dehiscence.

AIMS

To characterise the metalloproteinases present in intact and anastomosed ileum and colon to study their role in matrix degradation after surgery.

SUBJECTS

Tissue extracts of uninjured, and of anastomosed rat ileum and colon at postoperative days 1, 2, 3, 7, and 90, were used.

METHODS

Metalloproteinases were identified by gelatin and casein zymography. Aminophenylmercuric acetate (APMA) treatment was used to activate latent metalloproteinases.

RESULTS

Both uninjured ileum and colon contained a 60 and 67 kDa activity, but a 54 and 72 kDa gelatinase was present in ileum only, and a 51 kDa activity in colon only. APMA treatment converted the 60 kDa protease to 54 and 51 kDa forms and the 72 kDa protease to the 67 kDa form. These gelatinases may correspond to latent and active forms of MMP 1 and MMP 2, respectively. Additional metalloproteinases were observed after anastomotic construction. Both ileum and colon contained 95 and 230 kDa gelatinases, which were converted to 83 and 76 kDa forms by APMA. They may be the latent and active forms of MMP 9, respectively. Gelatinolytic activities of 25 and 28 kDa were only found in anastomosed ileum. Caseinolytic activities were only found in ileum extracts and those were most prominent at day 1, 2, and 3 after surgery.

CONCLUSIONS

The metalloproteinase pattern in ileum and colon differ considerably suggesting that matrix degradation after anastomotic construction may also vary.