Ileocolic Anastomoses

Abstract

Ileocolic anastomoses are commonly performed by surgeons in both open and minimally invasive settings and can be created by using many different techniques and configurations. Here the authors review both current literature and the author's preference for creation of ileocolic anastomoses in the setting of malignancy, inflammatory bowel disease, and colonic inertia. The authors also review evidence surrounding adjuncts to creation of anastomoses such as use of indocyanine green and closing mesenteric defects. While many techniques of anastomotic creation have adapted with new evidence and technologies, several key principles still provide the foundation for current practice.

Construction of intestinal anastomoses is commonly performed by surgeons in a variety of specialties. In particular, ileocolic anastomoses are often created after colonic resection for cancer, inflammatory bowel disease (IBD), or other indications. Despite being a mainstay of modern surgical practice, techniques and approach to ileocolic anastomoses vary widely by surgeon, center, and indication. In this article, we will highlight current evidence and approaches to these anastomoses and briefly review the author's preferences and current practice as it relates to creation of ileocolic anastomoses.

General Considerations

Ileocolic anastomoses can be constructed in several configurations using different techniques or combinations of techniques. Historically, hand sewn anastomoses were the most common type of intestinal anastomoses. Several different features of hand sewn bowel anastomoses have been considered including suture material, continuous or interrupted suture, single or multilayer closures, and tension on the anastomosis. ¹ A large systematic review of techniques for hand sewn colorectal anastomoses, including ileocolic anastomoses, concluded that “a single-layer continuous technique using inverting sutures with slowly absorbable monofilament material” was associated with lowest risk of postoperative complications. ² One weakness of hand sewn anastomoses is a heavy dependence on the technical expertise of the surgeon and ability to reproduce results consistently. Alternatively, stapled anastomoses offer a mechanical option for anastomotic construction and are often used in both open and minimally invasive surgical techniques. Staplers not only rely on tissue compression and multiple rows of staples spaced to adequately seal the bowel but also allow for consistent perfusion. ¹ While some early studies suggested that stapled anastomoses carried higher risk of anastomotic leak when compared with hand sewn techniques, ^{3 4} others have found decreased anastomotic leak rates in patients with stapled anastomoses. ^{5 6} A 2019 large multicenter study of over 4000 patients undergoing open right hemicolectomy found no significant difference in leak rates between patients with hand sewn and stapled ileocolic anastomoses. ⁷ This conflicting evidence highlights that while tissue staplers provide efficient, cost-effective, ⁸ and reproducible results, they are not without flaws and thus knowledge of anastomotic techniques is imperative.

Tissue staplers are constructed in a variety of forms, including cutting, noncutting, linear and circular staplers. Both linear and circular cutting staplers apply staples to the tissue and then cut the tissue between rows of staples. Noncutting staplers do not cut the tissue after applying staples, and the tissue is usually transected by the surgeon using a scalpel or scissors. Linear staplers are sized by stapler length, while circular staplers are sized by diameter. Linear staplers are commonly used to transect bowel and create side-to-side anastomoses, while circular staplers most commonly are used for end-to-side or end-to-end anastomoses. Circular staplers are particularly useful for low pelvic anastomoses but can also be used for ileocolic anastomoses if electing to perform stapled end-to-end or end-to-side anastomotic construction.

Side-to-side anastomoses are very commonly performed, particularly in the setting of size mismatch of two bowel lumens such as an ileocolic anastomoses. Side-to-side anastomoses can be configured in either antiperistaltic or isoperistaltic configuration. Traditionally, most side-to-side anastomoses were performed in an antiperistaltic manner. However, more isoperistaltic anastomoses are being performed, particularly in the context of minimally invasive surgery. ¹ Proponents of isoperistaltic ileocolic anastomoses highlight that these anastomoses typically require less mobilization of the bowel to achieve a tension-free anastomosis. While data are limited comparing these two techniques in the setting of ileocolic anastomoses, smaller studies suggest that either technique is safe and leads to comparable postoperative outcomes. ^{9 10} Thus, the decision to perform antiperistaltic versus isoperistaltic anastomosis can vary based on surgical approach, surgeon preference, and even indication for surgery.

There is very limited data on size and type of stapler use for performing an ileocolic anastomosis. For an antiperistaltic configuration, our preference is to use a GIA-75mm blue load to create a common channel ( Fig. 1 ) and then another GIA-75mm blue load to close the common enterotomy ( Fig. 2 ). If performing an open isoperistaltic anastomosis, then we will similarly use a GIA-75 mm blue load to create a common channel and then hand-sew the common channel closed with a running polydioxanone (PDS) suture. These techniques can vary among stapler size (i.e., 75–100 mm) as well as stapler type. Some use a TA stapler to close the common enterotomy.

Fig. 1.

Creation of the common channel using a GIA-75 mm blue load for an antiperistaltic ileocolic anastomosis.

Fig. 2.

Stapling the common enterotomy closed using a GIA-75 mm blue load for an antiperistaltic ileocolic anastomosis.

Construction Based on Underlying Disease

Anastomotic construction not only varies based on the factors discussed above but also varies based on indication for resection. Surgical principles guide colonic resections for various indications, and these may impact and drive the construction of ileocolic anastomoses.

Malignancy

In the setting of malignancy, anastomotic creation is most heavily influenced by principles of oncologic resection. Oncologic principles require complete resection of tumor with an adequate margin. Oncologic principles also require high ligation of the major vasculature to that specific portion of the colon to resect the corresponding primary lymphatic drainage of the tumor. ¹¹ Ileocolic anastomoses in the setting of resection for malignancy are most commonly performed after right hemicolectomy. For straightforward right-sided resections, the small bowel can easily be mobilized to facilitate reach for a tension-free ileocolic anastomosis, and extensive mobilization is not typically required. However, midtransverse colon tumors can present a unique challenge and often require extended right hemicolectomy to obtain adequate lymphadenectomy. In such instances, approximating the distal ileum to the remaining transverse colon can be difficult and may require additional mobilization maneuvers such as splenic flexure mobilization. ¹ Once the small bowel and/or remaining colon is appropriately mobilized, ileocolic anastomoses after right hemicolectomy can be performed open or minimally invasive in an intracorporeal or extracorporeal technique. A 2020 meta-analysis comparing intracorporeal and extracorporeal anastomosis after laparoscopic right hemicolectomy demonstrated decrease postoperative complications and length of stay among patients with intracorporeal ileocolic anastomoses. ¹² In open resections or extracorporeal anastomoses, the authors prefer a stapled side-to-side antiperistaltic anastomosis for ease of ergonomics and stapler positioning. However, if performed for Crohn's disease in the open setting, an isoperistaltic configuration is preferred for endoscopic surveillance ( Fig. 3 ). In the setting of minimally invasive resection, the author typically performs an intracorporeal isoperistaltic anastomosis.

Fig. 3.

Configuration of a side-to-side isoperistaltic ileocolic anastomosis.

Inflammatory Bowel Disease

In the setting of IBD, minimizing disease recurrence is an important consideration in anastomotic construction. In patients with ulcerative colitis, ileoanal anastomoses are more common and will be discussed in depth elsewhere in this issue. Nearly half of patients with Crohn's disease also require bowel resection at some point after their diagnosis, ¹³ and risk of disease recurrence is high with many patients requiring reoperation or additional intervention. ¹⁴ Mechanisms of disease recurrence are not well understood. However, as disease recurrence is lower in patients with end ileostomies ¹⁵ and the majority of recurrences are noted at the site of the anastomosis, anastomotic construction in this population is thought to play a role. Previous studies suggest that wide lumen anastomoses, most commonly stapled side-to-side anastomoses, are associated with better outcomes and lower rates of disease recurrence than hand sewn or end-to-end anastomoses after ileocolic resection. ^{16 17} Due to this evidence and reproducibility of stapled anastomoses in both minimally invasive and open settings, it is the preference of these authors to perform side-to-side isoperistaltic stapled anastomosis in the setting of ileocolic resection for Crohn's disease.

The Kono-S anastomosis is a more recently described anastomosis used specifically in the context of Crohn's disease. It was developed as a hand-sewn anastomosis using the antimesenteric sides of the intestine, which preserves the mesentery from the resected segment ^{1 18} ( Fig. 4 ). Early evidence suggests Kono-S to be safe and associated with lower rates of disease recurrence. ^{19 20} Specifically, a 2020 meta-analysis of nine studies enrolling 896 patients found that patients undergoing resection with Kono-S anastomosis had lower disease recurrence ranging from 0 to 3.4% compared with 15 to 24.4% among patients without Kono-S anastomoses. ²¹ Furthermore, Luglio et al randomized 79 patients with Crohn's disease undergoing ileocolic resection to Kono-S versus conventional anastomotic reconstruction in the SuPREMe-CD trial. Patients with conventional anastomoses had higher rates of endoscopic recurrence (odds ratio [OR]: 3.32) and clinical recurrence (3.47) than those with Kono-S anastomoses, ²² suggesting at least that some components of Kono-S construction may play a role in preventing disease recurrence.

Fig. 4.

Creation of Kono-S anastomosis (Courtesy of Dr. David Vargas, Ochsner Clinic).

Colonic Inertia

In select patients with colonic inertia or severe constipation refractory to medical management, total abdominal colectomy with ileorectal anastomosis may significantly improve symptoms and quality of life. ^{23 24 25} Ileorectal anastomoses have higher leak rates than ileocolic anastomoses ²⁶ despite the fact that ileorectal anastomoses typically are not at risk of tension or poor perfusion. In particular, higher leak rates after ileorectal anastomoses have been found in the IBD population, but persist in malignancy and benign disease as well. The mechanism of this increased leak risk in ileorectal anastomoses is not well understood, and anastomotic leak should be included in informed consent and discussion of surgical options for patients with refractory colonic inertia that are considering surgery.

Like anastomoses described above, ileorectal anastomoses can be performed in either hand-sewn or stapled fashion, and multiple options are available for stapler size and configuration. In a multicenter study of 227 patients undergoing ileorectal anastomosis, stapler size (<30 vs. >30 mm) did not significantly impact anastomotic leak rates. ²⁷ Additionally, ileorectal anastomoses can be performed end-to-end or side-to-end, anastomosing the side of the jejunum to the end of the rectum. It is the preference of the authors to perform stapled end-to-end anastomosis using 25 EEA stapler; however, many options exist without compelling evidence that one is superior than another.

Intestinal Bypass

Intestinal bypass was an early form of bariatric surgery performed in the 1950 to 1960s designed as a malabsorptive procedure. First described by Payne et al, the proximal jejunum was anastomosed to the transverse colon in an end-to-side fashion, and the remaining jejunum, ileum, and right colon bypassed. ²⁸ These anastomoses were associated with high rates of complications related to significant alterations in physiology and absorption. These procedures quickly fell out of favor due to high rates of complications including diarrhea, dehydration, and electrolyte abnormalities. ²⁹ Jejunocolic anastomoses may be more commonly seen now in the setting of extensive bowel resection for malignancy, IBD, or ischemia and may be associated with complications of short gut syndrome in some patients.

Adjuncts to Anastomotic Construction

Several adjuncts to anastomotic creation have been studied over the years in efforts to assist in operative decision making, decrease leak rates, and improve patient outcomes. Indocyanine green, or ICG, is being increasingly used in both open and minimally invasive surgery to aid in surgical decision making during creation of anastomoses. ICG is administered intravenously, and fluorescence indicates appropriate perfusion at the assessed site. This aids the surgeon in ensuring appropriate vascular supply at the site of a proposed anastomosis. Early evidence shows that ICG administration may reduce leak rates in patients undergoing low anterior resection, ³⁰ and a multicenter clinical trial demonstrated that ICG administration changed resection points in 8% of patients undergoing surgery for rectal cancer and left-sided colon cancers. ³¹ This technology is easy to use particularly when performing robotic surgery as most robotic cameras have built in fluorescent imaging capability. Thus, it is our preference to use ICG to assess vascular supply of all anastomoses during robotic resections. ICG can also be easily used in open surgery using the Woods lamp, and newer laparoscopic cameras also feature technology to use ICG or surgeons can use a robotic camera laparoscopically.

Oversewing staple lines in stapled anastomoses is another often used adjunct to anastomotic creation. Evidence is conflicted on the utility of oversewing staple lines to prevent anastomotic leakage, as some surgeons believe oversewing adds additional strength to the anastomosis, particularly when oversewing the common channel where some of the weakest points of the anastomosis are at intersecting staple lines. Others point out that oversewing may compromise perfusion to the staple line and thus predispose to leaks. Early literature investigating the utility of oversewing common enterotomies in stapled anastomoses after ileocolic resection suggested that oversewing staple lines resulted in lower rates of anastomotic leakage, ^{32 33} particularly in the setting of Crohn's disease. ^{34 35} A 2022 retrospective study of 737 patients undergoing ileocolic resection for Crohn's disease showed that patients who had both staple lines oversewn had decreased rates of anastomotic leak with OR 0.21 (95% confidence interval: 0.06–0.07, p  = 0.012) when compared with patients without oversewn anastomoses. ³⁵ Conversely, a large multicenter prospective study comparing anastomotic leakage rates among 1,347 patients in 32 countries undergoing right hemicolectomy demonstrated no significant difference in leak rates between patients with oversewn stapled anastomoses and those with stapled anastomoses not oversewn. ³⁶ It is the authors' practice to performed stapled side-to-side anastomoses while oversewing the common enterotomy staple line, particularly the corners and intersection with the common channel staple line.

Historically, closing mesenteric windows after bowel resection to reduce risk of internal hernia has been routinely performed without significant literature to support or refute this step. However, the increasing prevalence of minimally invasive colon resections leads to debate about the utility of closing mesenteric windows after laparoscopic colon resection, as laparoscopically closing the defect can be technically very difficult. A 2010 cohort study of 530 patients undergoing laparoscopic right hemicolectomy found that four patients in the study developed small bowel obstruction due to the mesenteric defect, which the authors argued did not support closing mesenteric defects laparoscopically. ^{37 38 39} Other studies demonstrated that closure of mesenteric defects after partial colectomy may in fact be associated with increased risk of postoperative complications such as bowel obstruction. ⁴⁰ Since the risk of internal hernia is very low after laparoscopic colon resection, ⁴¹ it is likely safe to assume that risk of internal hernia is low in open resection as well, thus perhaps not necessitating mesenteric window closure after open ileocolic anastomosis. As such, it is our practice to not close mesenteric windows after creation of both open and minimally invasive ileocolic anastomoses.

Conclusion

While technological advances and evolving literature on intestinal anastomoses, including ileocolic anastomoses, have led to changes in practice over the years, the core principles of anastomotic creation persist.