Epiphrenic Diverticula

Etiology

The most frequent location for esophageal diverticula is on the right side of the lower esophagus, occurring in approximately 70% of cases. Most patients have a single diverticulum, but about 15% may have multiple. These diverticula typically develop due to increased intraluminal pressure caused by functional obstruction in the distal esophagus, with common causes including achalasia, a hypertensive distal esophageal sphincter, and diffuse motility spasm. Previous studies have indicated that esophageal spasm accounts for 38% of cases, achalasia for 16%, and nutcracker esophagus for 8%—while 27% of patients exhibit normal esophageal motility. The condition can also occur as a postoperative complication of a tight fundoplication, which can lead to distal mechanical obstruction and increased intraluminal pressure.[6][7][8] Recognizing the etiology of epiphrenic diverticula is essential to determine the type of treatment necessary to decrease reoccurrence.

Epidemiology

Esophageal epiphrenic diverticulum, a pulsion diverticulum located in the distal third of the esophagus, is a rare condition with an estimated prevalence of approximately 0.02% to 3%.[9] Men show a slightly higher incidence, with a peak age between the sixth and seventh decades of life. Patients may be asymptomatic or experience complications such as esophagitis, bleeding from ulcerations, impaction, and stasis with regurgitation. These symptoms often overlap with those of achalasia or other motility disorders. The manifestations are typically caused by the underlying motility issue rather than the diverticulum itself, with no correlation to the size of the diverticulum. Cancer, specifically squamous cell carcinoma, is associated with epiphrenic diverticula. However, malignant transformation is rare, occurring in about 0.6% of patients. Affected individuals are more likely to be of the male sex (83%), older (mean age 68), and with larger diverticula (>5 cm).[10]

History and Physical

Epiphrenic diverticula present variably, depending on the size and the underlying motility disorder. The primary symptoms of esophageal epiphrenic diverticulum include dysphagia, regurgitation, weight loss, heartburn, respiratory issues, and retrosternal pain when swallowing food. Small diverticula without associated motility disorders may be asymptomatic, and the diverticulum is only discovered incidentally. However, larger diverticula or those with a concurrent motility disorder can present with worsening dysphagia and regurgitation—the 2 most common symptoms.

Other symptoms include chest pain, heartburn, nocturnal cough, and asthma. Worrisome symptoms include weight loss, aspiration pneumonia, hematemesis, melena, and odynophagia, which may signify malignant transformation into esophageal carcinoma. Complications can arise as the diverticulum grows and may include severe heartburn (secondary to stasis) or compression of neighboring structures (eg, the esophagus, lung, and heart).[11][12]

Evaluation

The anatomy of the diverticulum and the commonly associated motility disorders determine the type and range of diagnostic evaluation needed for the epiphrenic diverticulum. The workup usually consists of a barium swallow, esophagogastroduodenoscopy (EGD), and manometry. An esophagogram using barium contrast helps define the diverticulum's anatomical characteristics, guiding surgical planning. A contrast study helps determine the diverticulum's location and size, assess motility, and identify any associated strictures or lesions. These diverticula are most commonly noted on the right side (70%) and are single; however, up to 15% can occur in multiples.

Upper endoscopy helps visualize the inner esophageal lining, evaluating for ulcers, esophagitis, carcinoma, or hiatal hernia. Endoscopy typically confirms these findings, boasting a 91% sensitivity when used alone. Manometry is crucial for evaluating the motor functions of the esophagus. Manometry confirms the presence of a motility disorder. Each of these studies helps determine the type of surgery to be performed. For patients with symptomatic reflux, pH monitoring is necessary to distinguish between true reflux and reflux originating from a diverticulum. Some studies, however, argue that manometry and pH studies are not essential, as these modalities are used with the assumption that a distal motility disorder is always present.

Treatment / Management

The optimal surgical approach for epiphrenic diverticula is still debated. A thoracotomy was traditionally the standard procedure. However, recent minimally invasive surgery advancements have led to the adoption of the laparoscopic transhiatal approach, which has been widely reported. Despite its advantages, the laparoscopic transhiatal approach has potential drawbacks, such as the need for conversion to an unplanned transthoracic approach if the upper part of the diverticulum is not visible or dense adhesions are present. Addressing these drawbacks may necessitate unexpected changes in positioning or anesthesia techniques, such as switching to single-lung ventilation, and has been associated with a complication rate of up to 45% due to incomplete diverticulectomy and myotomy. Thus, determining the optimal surgical approach requires thorough preoperative planning and simulation.[13]

Surgical indications are not based on size but on symptoms such as worsening dysphagia, regurgitation, food retention, or complications such as aspiration pneumonia, perforation, and cancer. Asymptomatic epiphrenic diverticula may be managed nonoperatively. The surgical approach may be either open or laparoscopic/robotic, with a trend toward the minimally invasive approach due to its decreased pain, length of stay, and mortality.

Open approaches can be via laparotomy, left thoracotomy, or a combined thoracoabdominal approach. Minimally invasive procedures can be transhiatal or transthoracic, depending on the distance of the diverticulum from the lower esophageal sphincter. Robot-assisted devices like the Da Vinci Surgical System may also be used, offering better visualization than the traditional laparoscopic or thoracoscopic approach. Routine myotomy is commonly employed due to the high incidence of an underlying motility disorder. Without this procedure, diverticular recurrence rates can approach 20%, with leak rates approaching 24%.

The extent of subdiverticular myotomy is more critical than the proximal length when addressing the area of obstruction. This procedure is performed from 90° to 180° from the diverticulectomy site to avoid a leak. A myotomy is usually followed by a partial fundoplication to limit postoperative reflux, which has been noted to occur in 48% of patients versus 9.5% after a Dor fundoplication.

Differential Diagnosis

Epiphrenic diverticula may present in numerous ways, as previously mentioned; thus, the differential diagnosis can be vast. Symptoms of dysphagia and regurgitation may be present in other esophageal diverticula, such as Zenker and traction diverticula. A barium esophagogram can help distinguish these diverticula based on their anatomical location. These symptoms are also present in many esophageal motility disorders, which may or may not be the underlying cause of the diverticulum. Manometric studies can guide management. Other differentials to consider are acid reflux, hiatal hernia, benign tumors, and esophageal cancer, all of which can be differentiated based on the standard workup, including esophagogram, EGD, and manometry.

Prognosis

Asymptomatic epiphrenic diverticula are managed with nonoperative treatments. Patients develop complications or symptoms less than 10% of the time. The resolution of symptoms after surgical management in epiphrenic diverticulum approaches 90% in some studies, especially when diverticulectomy is combined with myotomy.[14]

Complications

Complications of epiphrenic diverticula can arise from both the disease and its treatment. Large diverticula can cause regurgitation, food stasis, and aspiration. Other complications, though rare, include ulceration, adhesions, abscesses, fistulas, bleeding, perforation, and malignant degeneration. Despite their rarity, a thorough evaluation is crucial before managing the diverticulum.

Postoperative complications may include leaks from the suture line or missed mucosal injuries during the myotomy, dysphagia resulting from an incomplete myotomy or tight wrap, and reflux. The most common postoperative complication is a suture line leak in 5% to 37% of patients. Key risk factors for leaks include using multiple staple cartridges, a wide diverticulum neck, and having a mediastinal location.[15]

Reported postsurgical morbidity rates range from 5.3 % to 50%, with mortality rates up to 9% and a leak rate of 16.6%. Surgical success is achieved in approximately 70% of cases, though symptoms remain unchanged at 21% and worsen at 8%. Postoperative acid reflux occurs in up to 60% of patients, a risk that may be mitigated by incorporating a partial fundoplication. Patients may have a successful outcome with a 22-month follow-up.