Anastomotic strictures are a significant complication following surgeries that involve reconnecting two hollow organs, a process known as anastomosis. This procedure creates a passageway between two previously separate parts of the body, most commonly in the digestive tract, such as after a bowel resection. A stricture describes an abnormal narrowing of this newly created junction that occurs during the post-operative healing phase. This narrowing can partially or completely obstruct the flow of contents, hindering the intended function of the surgery. The development of a stricture often requires follow-up intervention to restore normal passage.
Understanding Anastomotic Strictures
The narrowing that defines an anastomotic stricture results from the body’s natural healing response. When surgical trauma occurs, the body initiates a repair process involving inflammation and the laying down of new tissue. This repair uses granulation tissue, which contains specialized cells called myofibroblasts. Myofibroblasts actively produce collagen, the primary component of scar tissue, and possess contractile properties.
In a stricture, the formation of this collagen-rich scar tissue, or fibrosis, becomes excessive, creating a dense ring of tissue. The subsequent contraction of the myofibroblasts within this scar physically constricts the lumen, reducing its diameter and impeding the passage of fluids or solids.
Strictures are most frequently encountered in the gastrointestinal tract. They often follow procedures like colorectal resection, gastric bypass surgery, or esophagectomy. They can also occur in the urinary tract following surgery on the ureters or bladder neck.
Identifying the Underlying Causes
The excessive scar formation that causes a stricture is triggered by a combination of physiological, technical, and patient-specific factors. A primary physiological trigger is ischemia, which is a lack of adequate blood supply to the surgical connection. Insufficient blood flow causes tissue hypoxia, activating pro-fibrotic pathways that lead to impaired healing and subsequent contraction.
Technical aspects of the surgery also play a role in stricture development. Excessive mechanical tension at the connection site, often due to inadequate mobilization of the organs being joined, can compromise blood flow and healing. The selection of surgical tools, such as using a smaller diameter circular stapler or requiring multiple stapler firings, is also associated with increased risk.
Patient and disease factors contribute to the risk profile. Any condition promoting a prolonged inflammatory state increases the likelihood of excessive fibrosis. Anastomotic leakage, where contents leak from the connection, is a factor because the resulting infection and inflammation can increase the risk of stricture development. Preoperative radiation therapy, commonly used for rectal cancer, damages microvessels and tissue, creating a chronic inflammatory environment that predisposes the area to severe scarring.
Recognizing Signs and Symptoms
The clinical signs of an anastomotic stricture arise from the obstruction of flow, with symptoms depending on the location of the narrowing. In the upper digestive tract, a stricture in the esophagus or after gastric bypass surgery often presents as difficulty swallowing and the vomiting of undigested food shortly after eating. Patients may also experience a persistent feeling of fullness or pain in the upper abdomen.
When the stricture is located in the colon or rectum, symptoms relate to difficulty passing stool. This manifests as increasing constipation, abdominal pain and distention, or a feeling of incomplete evacuation. Some patients may report watery diarrhea, as only liquid can bypass the solid obstruction through the narrow opening. Any new or worsening obstructive symptoms following surgery warrant immediate medical attention.
Diagnostic Procedures and Management
To confirm the presence of an anastomotic stricture, endoscopy is typically the initial diagnostic procedure. This allows the physician to visualize the narrowed opening, assess the surrounding tissue, and measure the stricture’s diameter. A biopsy may be taken during this procedure to rule out underlying disease recurrence, especially if the original surgery was performed for cancer.
Imaging studies complement endoscopic findings, helping determine the length of the stricture and the extent of the obstruction. These studies include fluoroscopy, such as a barium swallow or hypaque enema, which use contrast dye and X-rays to visualize the internal structure. Computed tomography (CT) or magnetic resonance imaging (MRI) may also be performed to evaluate surrounding soft tissues and look for signs of inflammation or abscesses.
The management of benign strictures prioritizes minimally invasive options, with endoscopic dilation being the first-line treatment. This procedure involves passing a specialized balloon or bougie through the stricture and inflating it to stretch and fracture the dense scar tissue. Since a single dilation is often not sufficient, patients may require a series of treatments over time to maintain an adequate lumen size.
Alternative Endoscopic Treatments
For strictures that fail to respond to repeated dilation, other endoscopic techniques may be employed. These include the injection of corticosteroids into the scar tissue to inhibit inflammation and reduce the risk of re-narrowing. The temporary placement of self-expanding metal or biodegradable stents can also be used to hold the passageway open. If all non-surgical methods fail to provide long-term relief, surgical revision may become necessary, involving the removal of the scarred segment and the creation of a new anastomosis.