Govind Nandakumar

Laparoscopy for Rectal Cancer

Several large case series and single-institution trials have shown that laparoscopy is feasible for rectal cancer. Pending the results of the UK CLASICC, COLOR II, Japanese JCOG 0404, and ACOSOG Z6051 trials, the oncologic and long-term safety of laparoscopic rectal cancer surgery is unclear and the technique is best used at centers that can effectively collect and analyze outcomes data. Robotic and endoluminal techniques may change our approach to the treatment of rectal cancer in the future. Training, credentialing, and quality control are important considerations as new and innovative surgical treatments for rectal cancer are developed.

Surgical adhesive increases burst pressure and seals leaks in stapled gastrojejunostomy

BACKGROUND Leakage from a gastrointestinal anastomosis in bariatric surgery is a catastrophic complication and is the second-most preventable cause of death after Roux-en-Y gastric bypass. Several adjuncts for staple line reinforcement have been investigated to reduce the incidence of this complication. The purpose of our study was to determine whether a commercially available tissue sealant (BioGlue) could reinforce a stapled gastrojejunal anastomosis and whether it could seal an artificially created anastomotic leak. METHODS Circular-stapled gastrojejunostomies were performed on freshly explanted porcine stomach and intestine. Experiment 1 consisted of 10 control nonreinforced gastrojejunostomies and 10 gastrojejunostomies reinforced with BioGlue. The staple lines were submerged in saline and exposed to increased pressure using constant-rate infusion of air. The burst pressures were recorded at the point of visible leakage from the anastomosis. In experiment 2, a small defect was created in 10 gastrojejunostomies. The burst pressures were recorded before and after application of BioGlue to the anastomosis. The data were analyzed using the 2-tailed paired t test. RESULTS In experiment 1, the burst pressure was significantly increased in the reinforced gastrojejunostomies, from 27.4 ± 8.4 mm Hg to 59.1 ± 19.2 mm Hg (P <.001). In experiment 2, the defective gastrojejunostomies had an average burst pressure of 1.2 ± 0.8 mm Hg. After application of BioGlue, the burst pressure increased to 42.8 ± 15.9 mm Hg (P <.001). CONCLUSION These ex vivo findings suggest that the surgical adhesive BioGlue can reinforce both intact and defective stapled gastrojejunal anastomoses. Additional in vivo study is warranted to determine whether BioGlue can prevent or help seal gastrojejunal leaks.

Anastomoses of the lower gastrointestinal tract

Patients with gastrointestinal anastomoses are treated by physicians of multiple specialties, including gastroenterologists, radiologists and surgeons. This Review provides an overview of the surgical principles and techniques involved in the creation of lower intestinal anastomoses, including some of the mechanisms of healing. Anatomical configurations of small and large bowel anastomoses are illustrated. Stapled, hand-sewn, and sutureless anstomotic techniques are also discussed. Laparoscopy has revolutionized our approach to surgery of the gastrointestinal tract and we describe some of the current and future minimally invasive techniques for creating anastomoses. The article also highlights principles important in minimizing potential short-term and long-term complications such as anastomotic leaks and strictures. Common risk factors for dehiscence include poor nutrition, immunosuppression, microvascular disease, obesity and technical errors. An evidence-based review of perioperative and postoperative management of intestinal anastomoses is provided to help optimize patient care. The routine use of nasogastric tubes and mechanical bowel preparation has no documented benefits and could contribute to postoperative complications. Upcoming strategies that might prove useful to reinforce anastomoses are also reviewed.

Accuracy of CT enterography and magnetic resonance enterography imaging to detect lesions preoperatively in patients undergoing surgery for Crohn's disease.

BACKGROUND:CT enterography and magnetic resonance enterography have emerged as first-line imaging technologies for the evaluation of the gastrointestinal tract in Crohn’s disease. OBJECTIVE:The purpose of this work was to evaluate the accuracy of these imaging modalities to identify Crohn’s disease lesions preoperatively. DESIGN:This was a retrospective chart review. SETTINGS:The study was conducted at a single institution. PATIENTS:Seventy-six patients with Crohn’s disease with preoperative CT enterography and/or magnetic resonance enterography were included in the study. MAIN OUTCOME MEASURES:The number of stenoses, fistulas, and abscesses on CT enterography and/or magnetic resonance enterography before surgery were compared with operative findings. RESULTS:Forty patients (53%) were women, 46 (60%) underwent surgery for recurrent Crohn’s disease, and 46 (57%) had previous abdominal surgery. Thirty-six (47%) had a preoperative CT enterography and 43 (57%) had a preoperative magnetic resonance enterography. CT enterography sensitivity was 75% for stenosis and 50% for fistula. MRE sensitivity was 68% for stenosis and 60% for fistula. The negative predictive values of CT enterography and magnetic resonance enterography for stenosis were very low (54% and 65%) and were 85% and 81% for fistula. CT enterography had 76% accuracy for stenosis and 79% for fistula; magnetic resonance enterography had 78% accuracy for stenosis and 85% for fistula. Both were accurate for abscess. False-negative rates for CT enterography were 50% for fistula and 25% for stenosis. False-negative rates for magnetic resonance enterography were 40% for fistula and 32% for stenosis. Unexpected intraoperative findings led to modification of the planned surgical procedure in 20 patients (26%). LIMITATIONS:This study was limited by its small sample size, its retrospective nature, and that some studies were performed at outside institutions. CONCLUSIONS:CT enterography and magnetic resonance enterography in patients with Crohn’s disease were accurate for the identification of abscesses but not for fistulas or stenoses. Surgeons should search for additional lesions intraoperatively. Patients should be appropriately counseled regarding the need for unexpected interventions (see Video, Supplemental Digital Content 1, http://links.lww.com/DCR/A162).

Comprehensive models of human primary and metastatic colorectal tumors in immunodeficient and immunocompetent mice by chemokine targeting

Current orthotopic xenograft models of human colorectal cancer (CRC) require surgery and do not robustly form metastases in the liver, the most common site clinically. CCR9 traffics lymphocytes to intestine and colorectum. We engineered use of the chemokine receptor CCR9 in CRC cell lines and patient-derived cells to create primary gastrointestinal (GI) tumors in immunodeficient mice by tail-vein injection rather than surgery. The tumors metastasize inducibly and robustly to the liver. Metastases have higher DKK4 and NOTCH signaling levels and are more chemoresistant than paired subcutaneous xenografts. Using this approach, we generated 17 chemokine-targeted mouse models (CTMMs) that recapitulate the majority of common human somatic CRC mutations. We also show that primary tumors can be modeled in immunocompetent mice by microinjecting CCR9-expressing cancer cell lines into early-stage mouse blastocysts, which induces central immune tolerance. We expect that CTMMs will facilitate investigation of the biology of CRC metastasis and drug screening.

Laparoscopy for Colon and Rectal Cancer

Laparoscopy has emerged as a useful tool in the surgical treatment of diseases of the colon and rectum. Specifically, in the application of colon cancer, a laparoscopic-assisted approach offers short-term benefits to patients while maintaining a long-term oncologic outcome. Hand-assisted laparoscopic surgery may help decrease operative times while preserving the benefits of laparoscopy. The literature on the use of laparoscopy for rectal cancer is still in its early stages. Limited data suggest short-term benefits without compromising oncologic outcome; however, data from large multicenter trials will clarify the role of laparoscopy in the treatment of rectal cancer. Robotic proctectomy is a novel technique that may offer considerable advantage and overcome some limitations laparoscopy creates while working in the confines of the pelvis. The improved magnification and visualization offered with the robot may also assist in preserving bladder and sexual function. Transanal endoscopic microsurgery (TEM) for the treatment of T1 rectal cancers with low-risk features appears to be safe. However, TEM has a significantly higher recurrence rate when used to treat invasive cancer. Endoluminal techniques and equipment are under development and could offer more minimally invasive approaches to the treatment of colon and rectal cancer. Credentialing and training of surgeons and teams involved in the use of laparoscopy is important prior to making these techniques ubiquitous.

Surveillance, Epidemiology, and End Results-based analysis of the impact of preoperative or postoperative radiotherapy on survival outcomes for T3N0 rectal cancer

PURPOSE Preoperative chemoradiation has been established as standard of care for T3/T4 node-positive rectal cancer. Recent work, however, has called into question the overall benefit of radiation for tumors with lower risk characteristics, particularly T3N0 rectal cancers. We retrospectively analyzed T3N0 rectal cancer patients and examined how outcomes differed according to the sequence of treatment received. METHODS The Surveillance, Epidemiology, and End Results (SEER) database was used to analyze T3N0 rectal cancer cases diagnosed between 1998 and 2008. Treatment consisted of surgery alone (No RT), preoperative radiation followed by surgery (Neo-Adjuvant RT), or surgery followed by postoperative radiation (Adjuvant RT). Demographic and tumor characteristics of the three groups were compared using t-tests for the comparison of means. Survival information from the SEER database was utilized to estimate cause-specific survival (CSS) and to generate Kaplan-Meier survival curves. Multivariate analysis (MVA) of features associated with outcomes was conducted using Cox proportional hazards regression models with Adjuvant RT, Neo-Adjuvant RT, No RT, histological grade, tumor size, year of diagnosis, and demographic characteristics as covariates. RESULTS 10-Year CSS estimates were 66.1% (95% CI 62.3-69.6%; P=0.02), 73.5% (95% CI 68.9-77.5%; P=0.02), and 76.1% (95% CI 72.4-79.4%; P=0.02), for No RT, Neo-Adjuvant RT, and Adjuvant RT, respectively. On MVA, Adjuvant RT (HR=0.688; 95% CI, 0.578-0.819; P<0.001) was associated with significantly decreased risk for cancer death. By contrast, Neo-Adjuvant RT was not significantly associated with improved cancer survival (HR=0.863; 95% CI, 0.715-1.043; P=0.127). CONCLUSION Adjuvant RT was associated with significantly higher CSS when compared with surgery alone, while the benefit of Neo-Adjuvant RT was not significant. This indicates that surgery followed by Adjuvant RT may still be an important treatment plan for T3N0 rectal cancer with potentially significant survival advantages over other treatment sequences.

Hindgut Neuroendocrine Neoplasia

Neuroendocrine neoplasias (NENs) consist of a spectrum of tumors which can originate throughout the body, behave in a variety of different ways but are characterized by a similar histological appearance. This article reviews the classification, staging, diagnosis and treatment of Hindgut Neuroendocrine Neoplasias.

Colonic salvage with antiperistaltic cecorectal anastomosis.

BACKGROUND: Following colon resection, the construction of a well-perfused, tension-free isoperistaltic anastomosis can be made difficult by multiple factors including prior abdominal surgery or compromised vascular supply. Here, we describe the technique of antiperistaltic cecorectal anastomosis as a method for preserving viable colon without compromising functional outcome. TECHNIQUE: Following extensive colorectal resection, different techniques for isoperistaltic reconstruction using the cecum and ascending colon have been described, including the Deloyers procedure and limited isoperistaltic cecorectal anastomosis. However, these isoperistaltic reconstructions often require ligation of the middle colic and right colic arteries and/or sacrifice of viable distal colon to aid reconstruction. In complex situations that require preservation of normal vascular anatomy, an antiperistaltic cecorectal anastomosis can be constructed that maintains the orientation of the vascular pedicle. In addition to the preservation of the colonic arterial supply, a distinguishing feature of this technique is the substantial portion of antiperistaltic colon that is preserved and interposed to reestablish continuity. RESULTS: In a case where it was used, construction of an antiperistaltic cecorectal anastomosis was technically successful and led to a good functional outcome. CONCLUSION: Antiperistaltic cecorectal anastomosis should be considered as an option in colonic reconstruction for patients with extensive prior abdominal surgery or when complex anatomic issues require preservation of native vascular anatomy. In these situations, this technique offers several advantages over isoperistaltic reconstruction and may be the only option for reconstruction that uses the remaining cecum and colon.

Laparoscopic Hand-Assisted Low Anterior Resection

Laparoscopy for colon surgery is safe and effective. Laparoscopic rectal surgery remains technically challenging, and long-term oncologic outcomes to date are still under investigation. Hand-assisted laparoscopic surgery preserves several advantages of laparoscopy while decreasing operative time and expanding the reach of laparoscopy. This chapter focuses on the technical aspects of hand-assisted laparoscopic low anterior resection.