Small bowel exclusion from the pelvis by a polyglycolic acid mesh sling

Radiation enteritis

Radiation enteritis continues to be a major health concern in recipients of radiation therapy. The incidence of radiation enteritis is expected to continue to rise during the coming years paralleling the unprecedented use of radiotherapy in pelvic cancers. Radiation enteritis can present as either an acute or chronic syndrome. The acute form presents within hours to days of radiation exposure and typically resolves within few weeks. The chronic form may present as early as 2 months or as long as 30 years after exposure. Risk factors can be divided into patient and treatment-related factors. Chronic radiation enteritis is characterized by progressive obliterative endarteritis with exaggerated submucosal fibrosis and can manifest by stricturing, formation of fistulae, local abscesses, perforation, and bleeding. In the right clinical context, diagnosis can be confirmed by cross-sectional imaging, flexible or video capsule endoscopy. Present treatment strategies are directed primarily towards symptom relief and management of emerging complications. Recently, however, there has been a shift towards rational drug design based on improved understanding of the molecular basis of disease in an effort to limit the fibrotic process and prevent organ damage.

Radiation-induced small bowel disease: latest developments and clinical guidance

Ionizing radiation is commonly used to treat a number of malignancies. Although highly effective and now more targeted, many patients suffer side effects. The number of cancer survivors has increased and so there are more patients presenting with symptoms that have arisen as a result of radiotherapy. Radiation damage to small bowel tissue can cause acute or chronic radiation enteritis producing symptoms such as pain, bloating, nausea, faecal urgency, diarrhoea and rectal bleeding which can have a significant impact on patient's quality of life. This review outlines the pathogenesis of radiation injury to the small bowel along with the prevention of radiation damage via radiotherapy techniques plus medications such as angiotensin-converting enzyme inhibitors, statins and probiotics. It also covers the treatment of both acute and chronic radiation enteritis via a variety of medical (including hyperbaric oxygen), dietetic, endoscopic and surgical therapies.

[Surgical prevention of radiation enteritis: case report and review of literature]

Due to high morbidity and mortality rates, radiation enteritis is one of the most feared complications of abdominal and pelvic radiation therapy. Advances in radiation technology and radiation planning contributed to recent significant achievements. Surgical prevention provides further opportunities in decreasing the risk of radiation enteritis. A 75 year old male underwent transurethral resection for urothelial carcinoma of the bladder. Prior to initiation of radiation therapy, we performed Shouldice repair for bilateral inguinal hernias to prevent radiation injury to the fixed small intestines. Later our patient received 55 Gy of radiation therapy and two series of Carboplatin chemotherapy. Following radio-chemotherapy our patient did not developed radiation enteritis. In our report we discuss hernioplasty as an important method for prevention of radiation enteritis. We also review other options of surgical prevention.

Laparoscopic pelvic sling placement facilitates optimum therapeutic radiotherapy delivery in the management of pelvic malignancy

BACKGROUND

Radiotherapy has a significant role in the management of pelvic malignancies. However, the small intestine represents the main dose limiting organ. Invasive and non-invasive mechanical methods have been described to displace bowel out of the radiation field. We herein report a case series of laparoscopic placement of an absorbable pelvic sling in patients requiring pelvic radiotherapy.

METHODS

Six patients were referred to our minimally invasive unit. Four patients required radical radiotherapy for localised prostate cancer, one was scheduled for salvage localised radiotherapy for post-prostatectomy PSA progression and one patient required adjuvant radiotherapy post-cystoprostatectomy for bladder carcinoma. All patients had excessive small intestine within the radiation fields despite the use of non-invasive displacement methods.

RESULTS

All patients underwent laparoscopic mesh placement, allowing for an elevation of small bowel from the pelvis. The presence of an ileal conduit or previous surgery did not prevent mesh placement. Post-operative planning radiotherapy CT scans confirmed displacement of the small intestine allowing all patients to receive safely the planned radiotherapy in terms of both volume and radiation schedule.

CONCLUSION

Laparoscopic mesh placement represents a safe and efficient procedure in patients requiring high-dose pelvic radiation, presenting with unacceptable small intestine volume in the radiation field. This procedure is also feasible in those that have undergone previous major abdominal surgery.

How Safe is Adjuvant Chemotherapy and Radiotherapy for Rectal Cancer?

Over the last three decades, a series of clinical trials have led to the use of adjuvant pelvic radiotherapy and chemotherapy in high-risk (T3-4 or N1) rectal cancer. There is a need to improve patient selection in order to identify the group most at risk for recurrent disease. The toxicity of adjuvant therapy should be factored into this consideration. The optimal sequencing of adjuvant therapy before or after surgery, the use of short- or long-course radiotherapy, and the utility of concurrent chemotherapy is currently being examined in randomized controlled trials (RCTs). The aim of this report was to review the morbidity and mortality in all RCTs of adjuvant therapy for rectal cancer.

Initial clinical experience with intensity-modulated whole-pelvis radiation therapy in women with gynecologic malignancies

OBJECTIVE

Our goal in this article to describe our initial experience with intensity-modulated whole-pelvis radiation therapy (IM-WPRT) in gynecologic malignancies.

METHODS

Between February and August 2000, 15 women with cervical (9) or endometrial (6) cancer received IM-WPRT. All patients received a treatment planning computed tomography (CT) scan. On each scan, the target volume (upper vagina, parametrial tissues, presacral region, uterus, and regional lymph nodes) and normal tissues (small bowel, bladder, and rectum) were identified. Using commercially available software, an IM-WPRT plan was generated for each patient. The goal was to provide coverage of the target with the prescription dose (45 Gy) while minimizing the volume of small bowel, bladder, and rectum irradiated. Acute gastrointestinal (GI) and genitourinary (GU) toxic effects in these women were compared with those seen in 25 patients treated with conventional WPRT.

RESULTS

IM-WPRT plans provided excellent coverage of the target structures in all patients and were highly conformal, providing considerable sparing of the bladder, rectum, and small bowel. Treatment was well tolerated, with grade 0-1 GI and GU toxicity in 46 and 93% of patients, respectively. IM-WPRT patients had a lower rate of grade 2 GI toxicity (53.4% vs 96%, P = 0.001) than those treated with conventional WPRT. Moreover, the percentage of women requiring no or only infrequent antidiarrheal medications was lower in the IM-WPRT group (73.3% vs 20%, P = 0.001). While grade 2 GU toxicity was also lower in the IM-WPRT patients (6.7% vs 16%), this difference did not reach statistical significance (P = 0.38).

CONCLUSION

IM-WPRT provides excellent coverage of the target structures while sparing critical neighboring structures in gynecology patients. Treatment is well tolerated with less acute GI toxicity than conventional WPRT. More patients and longer follow-up are needed to evaluate the full merits of this approach.

Intensity-modulated whole pelvic radiation therapy in patients with gynecologic malignancies

PURPOSE

To evaluate the ability of intensity-modulated radiation therapy (IMRT) to reduce the volume of small bowel irradiated in women with gynecologic malignancies receiving whole pelvic radiotherapy (WPRT).

METHODS AND MATERIALS

Ten women with cervical (5) or endometrial (5) cancer undergoing WPRT were selected for this analysis. A planning CT scan of each patient was obtained following administration of oral, i.v., and rectal contrast. The clinical target volume (CTV) was defined as the proximal vagina, parametrial tissues, uterus (if present), and regional lymph nodes. The CTV was expanded uniformly by 1 cm in all directions to produce a planning target volume (PTV). The bladder, rectum, and small bowel were also delineated in each patient. Two plans were created: a standard "4-field box" with apertures shaped to the PTV in each beam's eye view and an IM-WPRT plan designed to conform to the PTV while minimizing the volume of normal tissues irradiated. Both plans were normalized to deliver 45 Gy to the PTV. Isodose distributions and dose-volume histograms (DVH) were compared.

RESULTS

The IM-WPRT plan reduced the volume of small bowel irradiated in all 10 patients at doses above 30 Gy. At the prescription dose, the average volume of small bowel irradiated was reduced by a factor of two (17.4 vs. 33.8%, p = 0.0005). In addition, the average volume of rectum and bladder irradiated at the prescription dose was reduced by 23% in both cases (p = 0.0002 and p = 0.0005, respectively). The average PTV doses delivered by the conventional and IM-WPRT plans were 47.8 Gy and 47.4 Gy, respectively. Corresponding maximum doses were 50.0 Gy and 54.8 Gy, respectively. However, on average, only 3.2% of the PTV received greater than 50.0 Gy in the IM-WPRT plans.

CONCLUSION

Our results suggest that IM-WPRT is an effective means of reducing the volume of small bowel irradiated in women with gynecologic malignancies receiving WPRT. This approach potentially offers a method for reducing small bowel complications in patients with gynecologic malignancies.

Morbidities of adjuvant chemotherapy and radiotherapy for resectable rectal cancer: an overview

PURPOSE

Although adjuvant chemoradiotherapy may improve outcomes after surgery for high-risk rectal cancer, its toxicities are not well documented. This is a review of complications associated with adjuvant therapy in randomized, controlled trials.

METHODS

A MEDLINE and literature search was performed for randomized, controlled trials of adjuvant therapy for rectal cancer. Modalities of adjuvant therapy evaluated included preoperative radiotherapy, preoperative chemoradiotherapy, postoperative radiotherapy, and postoperative chemoradiotherapy. All documented complications were analyzed, including any effect on pelvic floor function and quality of life.

RESULTS

Short-term (acute) complications of preoperative radiotherapy include lethargy, nausea, diarrhea, and skin erythema or desquamation. These acute effects develop to some degree in most patients during treatment but are usually self-limiting. With preoperative radiotherapy the incidence of perineal wound infection increases from 10 to 20 percent. The acute toxicities after postoperative radiotherapy for rectal cancer occur in 4 to 48 percent of cases, and serious toxicities, requiring hospitalization or surgical intervention, occur in 3 to 10 percent of cases. Postoperative radiotherapy is associated with more complications than preoperative radiotherapy. The main problems with postoperative radiotherapy are small-bowel obstruction (5-10 percent), delay in starting radiotherapy caused by delayed wound healing (6 percent) and postoperative fatigue (14 percent), and toxicities precluding completion of adjuvant therapy (49-97 percent). The morbidity and mortality of both preoperative and postoperative radiotherapy are higher in elderly patients and when two-portal rather than three-portal or four-portal radiation technique is used. Meticulous radiation technique is important, and multiple fields of irradiation are mandatory. After combined adjuvant chemotherapy and radiotherapy acute hematologic and gastrointestinal toxic effects are frequent (5-50 percent). Delayed radiation toxicities include radiation enteritis (4 percent), small-bowel obstruction (5 percent), and rectal stricture (5 percent). Pelvic floor function and quality of life have not been well evaluated in randomized, controlled trials.

CONCLUSION

Adjuvant therapy for rectal cancer has considerable adverse effects. Adverse effects on bowel and sphincter function and quality of life have not been defined.

Early experience with postoperative adjuvant chemoradiation for rectal carcinoma: focus on morbidity

The morbidity of postoperative adjuvant chemoradiation for primary extraperitoneal rectal carcinoma is documented in this ongoing study. Patients who presented electively for resection with ACPS Dukes' B and C extraperitoneal rectal carcinoma during the period January 1990 to June 1993 were studied. Twenty patients received postoperative adjuvant chemoradiation. At a mean follow up of 32.6 months (s.d. 7.1), three of the 20 patients who received combined adjuvant chemoradiation reported no side effects. In 10 patients (50%) complications were classified as minor. In the remaining seven patients (35%) major complications of therapy occurred. There were no deaths. These early results highlight the morbidity of postoperative adjuvant chemoradiation that has been presumed but not documented.

Effect of omental pedicle hammock in protection against radiation-induced enteropathy in patients with rectal cancer

PURPOSE

The aim of this nonrandomized study was to assess effects against radiation-induced enteropathy by constructing an omental pedicle hammock, thus isolating the small bowel outside the pelvis.

METHODS

Since 1991, 32 patients received the omental pedicle hammock procedure as an adjunct to definitive cancer surgery, and the perioperative experiences and toxic effects of radiation therapy were evaluated and compared with 25 patients who received pelvic floor reperitonealization only.

RESULTS

There were no surgical complications related to the omental hammock procedure. Contrary to control cases that showed the bowel to adhere deeply in the pelvis, exclusion of the small bowel from the pelvic cavity demonstrated by contrast study was successful in all except four cases of a segment of bowel loop descent within the radiation portals. According to acute and late radiation morbidity scoring criteria, 26 patients (81 percent) scored Grade 0 in the treatment group, whereas only 3 patients (12 percent) scored Grade 0 in the control group (P < 0.01) in the acute phase, and 28 patients (88 percent) of Grade 0 in the former group and 15 (60 percent) in the latter (P < 0.025) in late phase. There has been no case of radiation-induced enteropathy requiring surgical treatment.

CONCLUSION

The technique of bowel exclusion by pedicle omental hammock would make it possible to use higher doses of postoperative pelvic radiation therapy without fear of complications from radiation-induced enteropathy.

Laparoscopic enterolysis and placement of an intestinal sling before radiation therapy for the treatment of prostate cancer

We present an interesting application of laparoscopy in a man who was otherwise not a candidate for radiotherapy because of an adherent loop of small bowel in the proposed treatment field. Laparoscopic enterolysis was performed and the involved segment was displaced out of the pelvis; a synthetic mesh was placed to serve as a sling to prevent caudal migration back into the pelvis. The patient had a rapid recovery and subsequently completed a full course of radiotherapy. The experienced laparoscopist may find this a good alternative to open surgery in patients with a fixed loop of small bowel who require radiation therapy for pelvic malignancies.

Prevention of radiation enteritis in children, using a pelvic mesh sling

Between 1986 and 1991, the authors used polyglycolic acid mesh slings (placed at or above the sacral promontory) in eight children with pelvic malignancies to exclude all small bowel from the pelvis during pelvic radiation therapy. The only complications of this treatment were prolonged postoperative ileus (one patient) and temporary, partial small bowel obstruction (one patient). The average amount of radiation administered to the pelvis postoperatively was 5,349 +/- 556 cGy. In one of the eight patients, gastrointestinal symptoms (diarrhea for 24 hours) developed during radiation therapy. Early radiological evaluation confirmed that the small bowel was out of the pelvis in all five of the patients studied. Mesh disruption occurred between 2 and 5 months postoperatively (mean, 3.4 +/- 1.5 months) and was often identified symptomatically by the patient. Seven of the eight survived, with disease remission in six. Pelvic disease was absent at the time of death in the one patient who did not survive. Throughout the follow-up period (mean, 20 months) no survivor has had delayed symptoms of radiation enteritis. In children with pelvic malignancies in whom aggressive application of pelvic irradiation is required, the use of an absorbable pelvic mesh sling appears efficacious in preventing radiation-associated enteritis.

Efficacy of a synthetic mesh sling in keeping the small bowel in the upper abdomen to prevent radiation enteropathy in gynecologic malignancies

Radiation therapy in gynecological malignancies is limited by the frequent occurrence of radiation enteropathy at effective dose levels of 45 Gy and higher. Elevation of the small bowel out of the true pelvis should enable doses of up to 60-70 Gy to be given without damaging the small bowel. We report a feasibility study concerning elevation of the small bowel out of the true pelvis, by creating an intra-abdominal sling with a synthetic mesh. Twelve patients with pelvic gynecological malignancies were included since 1986. In all patients peroperative application of the mesh was possible. In ten patients adequate elevation of the small bowel was achieved. Two patients showed a right-sided herniation of a small bowel loop on a control barium opacification, performed 1 week postoperatively. In one of these a fistula occurred after resecuring the mesh. The most important problem in this study, as has also been reported elsewhere, was a herniation of a small bowel loop. The incidence is probably inversely correlated with the skill of the surgeon and will therefore be reduced with increasing experience. Future long-term studies should address the issue whether or not radiation enteropathy can be prevented by this method.

Use of peritoneal insufflation to displace the small bowel during pelvic and abdominal radiotherapy in carcinoma of the cervix

Peritoneal insufflation is a technique which reliably displaces small bowel from pelvic and abdominal radiotherapy fields with the aim of reducing bowel reactions which limit the dose of radiation applied to these sites. Use of this technique in five patients undergoing radiotherapy for advanced carcinoma of the cervix, and the degree of bowel displacement resulting, dosimetry, acute reactions and tolerability of the technique are presented, with discussion of the possibility of future escalation in radiotherapy dose.

Radiation therapy for advanced colorectal cancer

Locally advanced, inoperable, and recurrent colorectal cancer requires multitechnique therapy to achieve optimal control and palliation. The role of radiation therapy as an adjuvant in resectable rectal cancer has been studied extensively in clinical trials, but its role in more advanced disease has not been explored to the same extent. The use of radiation in colonic rather than rectal cancer is more problematic because of natural tissue tolerance constraints in the abdomen versus the pelvis. The current and past role of radiation in advanced colorectal cancer will be reviewed, and avenues of ongoing and future investigation will be outlined. The role of radiation for palliation also will be discussed.

Pelvic peritoneal reconstruction to prevent radiation enteritis in rectal carcinoma

Some patients with rectal cancer who undergo exenterative surgery may require radiation therapy as an adjuvant treatment for recurrent or residual disease. A common devastating side effect of this treatment modality is radiation enteritis, a radiation-induced small bowel injury. Hence, the prevention of such a complication is essential for both the surgeon and the radiation oncologist. A new surgical method using the posterior rectus sheath and peritoneum to partition the abdominal cavity at the level of the umbilicus to the sacral promontory seems to accomplish this purpose, keeping the small bowel away from the pelvic cavity. After removal of the rectal lesion [eight abdominoperineal resections (APRs), nine Hartmann's procedures, and one low anterior resection (LAR)] in 18 patients with rectal cancer, this new surgical procedure was performed. One of the patients had an early postoperative intestinal obstruction, and all but one of the patients received postoperative adjuvant radiation therapy. In addition, a small bowel series was performed before the radiation therapy and six months and one year after surgery. Upon examination, most of these patients still had their small bowel kept intact in the abdominal cavity. During the follow-up period of 10 months to 2 years with an average of 18 months, two late complications of intestinal obstruction were noted. Exploratory laparotomy of these two patients revealed radiation enteritis of the small bowel. Therefore, the failure rate of the following procedure is 12 percent, since 2 of the 17 patients received small bowel injury. Although the follow-up period for this surgical method is short, the results have encouraged us to continue the use of this procedure on advanced rectal cancer patients who require postoperative radiation therapy.

Experience with high-dose radiation therapy and the intestinal sling procedure in patients with rectal carcinoma

BACKGROUND

Surgery for Dukes' Stage B2 or C rectal carcinoma has a locoregional recurrence rate of 15-67%; this rate is significantly reduced when postoperative radiation therapy (RT) is given. However, RT contributes to radiation-associated small bowel injury in a dose-dependent manner.

METHODS

Polyglycolic acid mesh used as an intestinal sling is able to keep the small bowel out of the pelvis during RT, thereby preventing radiation-associated small bowel injury.

RESULTS

The authors reviewed the perioperative experiences and acute toxic effects of RT in 53 patients in whom the polyglycolic sling was placed from May 1985 through May 1990 during laparotomy for rectal malignancies (47 primary and 6 recurrent). There were 26 men and 27 women whose ages ranged from 34 to 88 years (mean, 64.7 years). Mild postoperative ileus occurred in most patients, and one patient had an anastomotic leak with a pelvic abscess. Bowel displacement from RT portals was confirmed using radiologic contrast studies. Forty-three patients with primary tumors have completed postoperative RT, and a mean of 5174 cGy has been administered.

CONCLUSIONS

After 1-6 years of follow-up (mean, 2.1 years), eight patients have died of systemic disease. There were no cases of radiation-associated small bowel injury and only two cases of pelvic recurrence from primary rectal adenocarcinoma (5%).

Prevention of radiation enteritis by an absorbable polyglycolic acid mesh sling. A 60-case multicentric study

Radiation-induced small bowel injury is a limiting factor to postoperative tumoricidal pelvic doses exceeding 4500 to 5000 cGy. Data from a review of the literature showed the inadequacy of medical measures and the bad reproducibility of radiation therapeutic attempts to decrease small intestine damage. Recent studies cited the benefit of a polyglycolic acid mesh to create an absorbable intestinal sling and suspend the loops above the pelvic radiation field. In 60 cases of gynecologic and rectal malignancies with a surgical intestinal morbidity of 8.3% (5 cases), the rate of radiation enteritis was 7% (4 cases) with an average follow-up of 17.8 months (range, 1 to 57 months). The quality of small intestinal elevation and the absence of loop herniation were demonstrated by the barium index. Magnetic resonance imaging was used for checking the polymer polyglycolic acid mesh position and its complete resorption at the third to fifth postoperative month. The authors conclude that this new procedure is safe in selected patients with high pelvic recurrence risk after optimal surgery, in residual disease after debulking surgery, or at the time of exploration for unresectable pelvic tumors. Clinical studies are ongoing to evaluate the long-term efficacy of this surgical technique to prevent chronic radiation enteropathy and improve locoregional control in advanced pelvic carcinomas.

A preliminary report on new efforts to decrease radiotherapy related small bowel toxicity

Ten consecutive patients operated for gynaecological cancer had an absorbable polyglycolic mesh (Dexon) inserted to elevate the small bowel out of the pelvis to prevent radiation toxicity. Four patients developed minimal small bowel toxicity, while no complications of the mesh were seen. The method warrants further investigation.

Use of Dexon Mesh for abdominal partitioning above the peritoneal reflection

Dexon Mesh (Davis & Geck, Sugarland, TX) was used to partition the abdomen after incomplete resection of a locally advanced left colon cancer. Following surgery, external beam radiotherapy was delivered to the left flank without the risk of radiation enteritis. The technique of abdominal partitioning using Dexon Mesh is described.

Intestinal complications associated with use of the Dexon mesh sling in gynecologic oncology patients

Three cases of postoperative enterocutaneous fistula formation following use of the Dexon mesh sling are reported from two gynecologic oncology services. Two patients had intestinal trauma or bowel resection at the time of mesh placement. Postoperative submesh abscess formation was noted in only one patient. Factors which might predispose to fistula formation after mesh placement, particularly in previously radiated patients, and techniques which might be used to avoid this complication are discussed.

Is total pelvic exenteration reasonable primary treatment for rectal carcinoma?

Total pelvic exeneration (TPE) is reasonable primary surgical therapy in select patients with large bulky locally invasive rectal cancers that can be removed en bloc. Many do not have either nodal or distant metastasis. Furthermore, TPE can be curative and often is palliative for similar lesions that are recurrent or nonresponsive to radiation therapy. Operative mortality rates should be under 10% and can be under 5% for primary cases. Although improvement in preoperative management and operative technique, especially with urinary conduits and postoperative care is clear, both early and late complications are significant. Unfortunately, preoperative identification of those patients requiring TPE rather than abdominoperineal or low anterior resection remains poor. Furthermore, recent improvements in techniques for pelvic slings to prevent small bowel entrapment and protection from irradiation or myocutaneous flaps to obliterate the massive dead space are not yet clearly established as preventors of either early or later complications.

Efficacy of an absorbable mesh in keeping the small bowel out of the human pelvis following surgery

Patients with pelvic malignancies frequently require postoperative radiation therapy either as adjunctive or palliative treatment. Tumoricidal doses, however, are frequently associated with small-bowel damage. Animal experiments demonstrated tolerance to high-dose radiation therapy and protection from radiation enteritis by use of an absorbable polymer polyglycolic acid (PGA) that is used as an intestinal sling to elevate the small bowel away from the operated site. Sixty patients (42 with rectal carcinomas and 18 with gynecologic malignancies) underwent surgical treatment that included the intestinal sling procedure. Postoperative radiation was begun within three weeks following surgery and patients received a mean approximating 5500 rads in fractionated doses. A mean follow-up time of 28 months has not revealed a single case of radiation enteritis (by either contrast studies or physiologic studies) or PGA mesh-related complications. The authors believe that this surgical technique should be employed in patients who may require postoperative radiation treatment for pelvic malignancy.

The current role of ultraradical surgery in the treatment of pelvic cancer

Based on the results of experience accumulated in the past 30 years, exenterative pelvic surgery should be a part of the armamentarium of specially prepared oncologic surgeons. It is most frequently indicated for radiation failures in the treatment of carcinoma of the cervix, although it may be justified as primary treatment of selected cases of stage IV lesions without evidence of dissemination outside the pelvis. It is also justified for postirradiation radionecrosis causing sloughing and fistula, provided adequate relief cannot be offered by simple urinary and fecal diversion. For carcinoma of the rectum and pelvic colon, exenteration has a role in the advanced lesions that appear not to have become disseminated outside the pelvis but that involve contiguous viscera. Reoperation for recurrent carcinoma of the rectum is rarely successful, and this dreaded complication is best avoided by a well-planned and adequate standard first operation, or by the early recognition that a more extended operation is necessary. It is to be hoped that adjuvant radiation therapy, either preoperative or postoperative, or both, may be proved effective in preventing recurrence, especially for lesions below the peritoneal reflection, which is the most frequent site of recurrent disease. Finally, ultraradical pelvic surgery has reached its anatomical and pathologic limit. It only remains for the mortality and survival results to be further improved by continued refinements in the technicalities of the operation and in the judgment and selection of patients for it. Multimodal adjunctive therapy has an emerging role, as does selection of patients for functional preservation and reconstruction. The procedures should continue to be done in institutions where special studies are being conducted and where trained and experienced personnel are available with the necessary ancillary services.

Efficacy of polyglycolic acid mesh sling in keeping the small bowel in the upper abdomen after abdominal surgery: a 12-month study in baboons

The purpose of this study was to determine if a "sling" made of polyglycolic acid (PGA) would be a reliable method of preventing small bowel descent into the pelvis following abdominal surgery. Baboons were used, as they respond to infection and ambulate similarly to humans. Animals had the small bowel mobilized to the upper abdomen and had the PGA "sling" sewn into place. Documentation of small bowel position was evaluated by upper gastrointestinal series over the 12-month study. Small bowel descent into the pelvis was prevented by utilization of the PGA "sling." Animals were sacrificed and autopsied, and sections of small bowel were taken. There was no evidence of mesh, obstruction, sepsis, fistulae, or herniation in animals at autopsy. Small bowel sections were considered normal histologically. Utilization of PGA sling appears to be a safe and reliable method of preventing small bowel descent into the pelvis after abdominal surgery.

Protection from radiation-associated small bowel injury with the aid of an absorbable mesh

Radiation associated small bowel injury results from aggressive treatment of pelvic malignancies with radiation therapy. The incidence increases when radiation therapy follows pelvic surgery due to adhesions that form between the small bowel and the operated site. Application of an absorbable polyglycolic acid mesh to keep the small bowel from descending into the pelvis and around the operated site prevents this complication. Use to date in humans and non-human primates has not been associated with any complications.

New surgical approach to minimize radiation-associated small bowel injury in patients with pelvic malignancies requiring surgery and high-dose irradiation. A preliminary report

Complications associated with small bowel intolerance to radiation therapy at doses higher than 4500 to 5000 cGy have been the limiting factor in delivering pelvic radiation either as an adjuvant to surgery or alone in the treatment of pelvic malignancies. Despite numerous surgical, medical, and radiation therapy technical measures to minimize small bowel injury, none have been uniformly successful in eliminating this problem. With the availability of a new synthetic absorbable mesh, a pelvic sling can be placed at the time of exploration or definitive surgery aimed at suspending the small bowel out of the pelvis. Preliminary work in animal models has shown the mesh sling to be well-tolerated and successful. Barium-contrast simulation studies of seven patients with pelvic malignancies requiring resectional surgery and postoperative radiation therapy in whom the mesh sling was placed at the time of surgery demonstrate total exclusion of the small bowel from the pelvic radiation treatment field. All patients have been followed for at least 4 months since mesh placement, and to date no complications have occurred. It is possible that this technique of bowel exclusion will permit the delivery of larger doses of radiation therapy in patients with pelvic malignancies aiming at more effective local and regional control of cancer without increased complications from radiation-associated small bowel injury.