Transhiatal esophagectomy (THE) is an accepted operation for resectable malignant diseases of the esophagus. Complications following this operation vary and usually occur early in the postoperative period. Mediastinal herniation after THE is an unusual postoperative complication. The authors report on three patients who experienced mediastinal herniation of abdominal contents as a late complication of THE, yet who presented in a distinctly different manner from one another.

Transhiatal esophagectomy (THE) is an accepted approach for resecting esophageal malignancies. Postoperatively, various complications may develop, which usually involve the respiratory or gastrointestinal systems. Mediastinal herniation through the esophageal hiatus is a rare late complication, which can produce respiratory and gastrointestinal symptoms. Bowel obstructions have been known to occur, but the etiology typically has been attributed to causes other than the mediastinal herniation. Although several different incidence rates of mediastinal herniation after THE have been reported,^1-3 its true incidence is unknown. We report three unique cases of mediastinal herniation of abdominal contents following THE.

Case reports
Case 1—A 69-year-old man went to the emergency department after experiencing 10 hours of severe abdominal pain that had worsened during the immediate 2 hours before his presentation. He reported no nausea, vomiting, fever, or chills. He had undergone THE for Barrett’s adenocarcinoma 1 year earlier and had a normal upper gastrointestinal fluoroscopic examination 3 months after being discharged.

On physical examination, the patient was noted to have an extremely tender abdomen with involuntary guarding on palpation. His abdomen was scaphoid, and bowel sounds were normal on auscultation. An abdominal obstructive series showed dilated small bowel loops without the presence of free air (Figure 1). A chest radiograph was interpreted as showing loops of small bowel in the left chest (Figure 2). A clinical diagnosis of a complete small bowel obstruction was made.

An exploratory laparotomy was performed, during which both normal and dilated small bowel loops were identified. A band of mesentery and small bowel coursed through the diaphragmatic hiatus into the mediastinum. The small intestine was reduced easily without lysis of any adhesions. The hiatal opening was not observed to be particularly large and was considered an unlikely site of herniation despite the operative findings. After the small bowel reduction, no further repair was performed except for creating an omental buttress at the hiatus. No other pathology was observed, and the abdomen was closed. The patient was discharged on postoperative day 10.

Case 2—A 42-year-old man underwent THE for moderately differentiated adenosquamous cell carcinoma (T2N0M0) of his lower esophagus. His postoperative course was complicated by a chylous fistula, which required ligation of the thoracic duct via a right thoracotomy. After being discharged from the hospital, he underwent adjuvant chemotherapy and radiotherapy. Approximately 3 years postoperatively, he reported progressive shortness of breath. His abdomen was scaphoid, and bowel sounds were normal on auscultation. Although previous follow-up computed tomography (CT) scans were normal, a subsequent one showed a new finding of small bowel loops within the mediastinum (Figure 3).

Since mediastinal herniation was demonstrated to be causing the patient’s shortness of breath, an exploratory laparotomy was performed. The operation revealed herniation of the small bowel and a portion of the colon through a large hiatus into both the right and left thoracic cavities (Figure 4). The small and large bowel were reduced by careful traction, and no adhesions to the mediastinum were observed. The hiatus was too large to be left alone and could not be repaired, primarily due to its size and adjacent fibrosis. A polytetrafluoroethylene (PTFE) patch was placed around the gastric tube and sutured circumferentially to the edges of the hiatal defect (Figure 5). No other pathology was observed, and the abdomen was closed. The patient had an uneventful recovery and was discharged home on postoperative day 7.

Case 3—A 74-year-old man underwent THE for well-differentiated adenocarcinoma of his distal esophagus (T1N0M0) 10 years before presenting with biliary colic. His surgical history was significant for a hiatal hernia repair, vagotomy, pyloroplasty, and gastrostomy. During esophagectomy, the diaphragmatic hiatus was found to be fibrotic and there were adhesions to the omentum. Postoperatively, the patient’s course was complicated by a cervical anastomotic leak and an empyema that required tube thoracostomy drainage. His current presentation of biliary colic, which occurred almost a decade after undergoing THE, was managed with a laparoscopic cholecystectomy at an outside hospital. The patient’s postoperative course was complicated by a biliary fistula, and he required endoscopic stenting. As part of the workup for the bile leak, he underwent an abdominal CT scan, which revealed herniation of the small bowel and a portion of the splenic flexure of the large colon into the mediastinum (Figure 6). An additional upper gastrointestinal fluoroscopic series confirmed the presence of the mediastinal hernia (Figure 7). Because the patient was asymptomatic and there was no radiographic evidence of obstruction, he did not undergo surgical exploration and is being followed expectantly.

Discussion
Herniation of the abdominal contents into the mediastinum has been described in the literature, but primarily as an acute or early complication of esophagectomy.^4-8 Both the Ivor-Lewis and transhiatal approaches have been associated with this complication during the early postoperative period, and with increased usage of THE, this complication is being described with growing frequency.^4-7 Herniation of the colon has been reported as a late complication of THE,^1,9-11 and small bowel herniation causing obstruction has been described as an early complication of this procedure.¹² One case of mediastinal herniation that caused complete obstruction and required reoperation was described as occurring in the late postoperative period; however, in that case, concomitantly incarcerated omentum, colon, and proximal jejunum were reduced through the diaphragmatic hiatus via a left thoracotomy.¹³ 

van Sandick and colleagues specifically evaluated the occurrence of diaphragmatic herniation following esophagectomy and identified 9 of 218 patients with intrathoracic herniation of abdominal contents.¹⁰ Of these nine patients, one presented 4 months postoperatively with signs and symptoms of intestinal obstruction. In retrospect, this patient’s hernia was thought to have occurred in the early postoperative period based upon chest radiographs performed at that time. Six of the nine patients underwent surgery for their diaphragmatic hernia, three of which were noted to have small bowel involvement.10 Similarly, among a series of 50 patients, Barbier and colleagues identified 3 who had diaphragmatic herniation through the esophageal hiatus in the late postoperative period (defined as occurring between 3 to 9 months postoperatively).³ A more comprehensive meta-analysis determined that the reported incidence of this complication following THE was 5 out of 1,353 (0.4%) patients.²

When performing THE, placement of the surgeon’s hand through the diaphragmatic hiatus allows safe mobilization with tactile guidance and avoids injury to the mediastinal structures.^9,14,15 This maneuver results in the enlargement of the hiatus, which is usually of negligible consequence. Enlargement of the esophageal hiatus by incising the diaphragm rarely has been associated with the development of diaphragmatic hernias.^4,10,13 It has been suggested that mediastinal herniation may be prevented either by narrowing the hiatus following mobilization of the stomach or tacking the stomach to the diaphragm.^7,9,11 It has been our experience that these maneuvers are not required because the gastric conduit is usually sufficient to occupy the entire diaphragmatic hiatus.

Our report of complete small bowel obstruction due to mediastinal herniation has been the only one we have identified. In this one case, the hiatus was not particularly enlarged, leading us to believe that routine hiatal closure would not have helped this patient. Venous congestion of the esophageal substitute is another reason that the enlarged hiatus is not narrowed routinely.¹⁰ Excessive approximation of the hiatal tissue can result in the development of gas bloat syndrome.¹³ PTFE mesh repair of an enlarged esophageal hiatus has been described before, following an Ivor-Lewis esophagectomy in the early postoperative period,⁸ but not after THE.

An intra-abdominal approach is recommended for reducing mediastinal herniation after THE, because it allows for lysis of adhesions and facilitates reduction of the herniated intestines with gentle traction.^10-13 The abdominal approach permits expedient access, wide exposure, and adequate surveillance of bowel viability after the herniated small bowel is reduced.^1,10 

When mediastinal herniation of abdominal contents has been discovered postoperatively in patients who have undergone THE, it was usually after they manifested  signs or symptoms attributed to the gastrointestinal tract or pulmonary system.^10,12-13 Abdominal and respiratory signs have been reported with about the same frequency. Operative intervention has been based on the degree of the patient’s symptoms. Progressive worsening of abdominal or respiratory conditions is a clear indication for surgical intervention.

Conclusion
When any gastrointestinal or pulmonary signs or symptoms are present, an aggressive operative approach should be pursued. This is especially true for patients with bowel obstruction and no previous abdominal operations other than THE. Small bowel obstructions are very rare in such cases, because of the absence of infracolic adhesions. Mediastinal herniation as the cause of obstruction should be considered strongly in the differential diagnosis, and operative intervention should be immediate, because the consequences of mediastinal rupture of the small bowel are disastrous. While long-term observation can be considered for asymptomatic patients, it is important to maintain a high index of suspicion that will trigger aggressive management upon the development of signs or symptoms related to mediastinal herniation.

Upper or lower gastrointestinal fluoroscopic imaging or CT scanning can be extremely helpful in diagnosing mediastinal herniation. In gastrointestinal fluoroscopic imaging, the presence of retrocardiac air can be highly suggestive of bowel herniation.⁵ 

During the initial THE, surgical narrowing of the esophageal hiatus is not required as a preventative measure. If abdominal exploration for mediastinal herniation is undertaken, the hiatus can be repaired using a simple omental buttress or PTFE mesh repair.

References
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