Posttraumatic Transdiaphragmatic Intercostal Hernia: Report of a Case and Review of the Literature

The herniation of abdominal contents through the thoracic wall, as a result of the disruption of diaphragmatic and/or intercostal muscles, is an uncommon clinical entity.^1–3 This condition is usually reported to occur following penetrating or blunt injuries of the thoracic wall.⁴ However, there are several cases that have been described to be a consequence of a coughing–spell rib fracture, usually in patients with other predisposing factors such as chronic obstructive pulmonary disease, asthma, advanced age, or osteoporosis.^1,3,4

The present report describes a case of a middle-aged obese patient that developed a transdiaphragmatic intercostal hernia involving the liver and the ascending colon 6 months after a traumatic incident. The underlying mechanism, the anatomical and diagnostic considerations, as well as the treatment options are also discussed.

Case Report

A 53-year-old obese woman, with significant history for chronic obstructive pulmonary disease, presented to our respiratory medicine clinic complaining of dyspnea. Six months before presentation, she had a motor vehicle accident where she suffered multiple upper and lower extremity fractures that were surgically treated. The clinical and laboratory examination revealed a paradox movement in the right thorax and type I respiratory disease. A computed tomography (CT) scan was executed, which revealed fractures of the 8th and 9th ribs. The patient was treated conservatively with medications and rescheduled for a visit 1 month later.

On her second appointment, the patient presented with an improved respiratory function, but also with an evident protrusion in the right lower thorax (Fig. 1). The protruding mass was reducible, and there were evident bowel sounds in the auscultation of the area. On CT, the defect measured 10 × 7.6 cm and the sac contained part of the segment VI of the liver, as well as part of the ascending colon (hepatic flexure) along with its mesocolon (Fig. 2).

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A surgical repair of the defect was performed under general anesthesia, with the patient in left lateral decubitus position. Upon dissection, a large defect between the 8th and 9th rib was identified. Due to the patient's position, the contents of the hernia were already reduced, and the sac was opened through an oblique incision in the enlarged 8th intercostal space (Fig. 3). The further exploration of the area revealed degeneration of the diaphragmatic attachment to the lateral thoracic wall, through which the hernia contents were also protruding within the right hemithorax. The defect was repaired using a prosthetic patch (GoreTex; WL Gore & Associates, Inc., Flagstaff, AZ, USA; Fig. 4). The patient's postoperative course was uneventful and she was discharged on the 5th postoperative day. The patient had a follow-up CT 3 weeks after surgery that showed full closure of the defect, and remains recurrence free at her 12-month follow-up.

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Discussion

Intercostal hernias occur most frequently following a traumatic incident that has resulted in the disruption of intercostal and/or diaphragmatic muscles, either penetrating or blunt. When the abdominal viscera enter the intercostal space through an associated diaphragmatic defect, the term “transdiaphragmatic intercostal hernia” is usually used.² If no diaphragmatic abnormality is involved, the term “abdominal intercostal hernia” is more appropriate.²

Intercostal hernias have been described to occur with two distinct mechanisms: First, they can occur acutely secondary to a penetrating trauma or a direct blunt trauma,⁵ or even after repeated violent coughing episodes.^1,3,4 The second mechanism is the delayed presentation, as described in the present case, where the physical activity and respiratory movements lead to enlargement of an initially small defect in the thoracic wall and/or the diaphragm that might initially be occult.^5,6

From an anatomical point of view, the chest wall is weaker from the costochondral junction to the sternum, due to the lack of external intercostal muscle support, and from the costal angle posteriorly to the vertebrae due to the lack of internal intercostal muscle support.⁷ Lung or abdominal contents may be herniated upon development of defects in these areas,⁸ although usually the weakened space is a result of a traumatic incident.

Both transdiaphragmatic and abdominal intercostal hernias are scarce in the medical literature.⁹ The first description of chest wall intercostal hernia is attributed to Roland et al. as early as 1499.¹⁰ On the other hand, Croce and Mehta¹¹ were the first to report a case of abdominal intercostal hernia, or “intercostopleuroperitoneal” hernia, as they termed it. Although rare in the existing literature, these types of hernias have been suggested to actually be more frequent than the literature indicates, as their course is often asymptomatic.^9,12

More common on the left thoracic side,⁹ these types of hernias are almost always located inferiorly to the seventh rib, and may contain omentum, colon, spleen, stomach, and/or small bowel.¹² There are only a few reports, including the present, of liver segments being contained in an intercostal hernia, with or without other coexisting abdominal viscera (Table 1).^{4,5,10,12–17}

Table 1 Overview of published cases of intercostal hernias containing liver segments

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The diagnosis of intercostal hernia has been historically challenging, with the interval between the initial traumatic incident and the repair of the hernia varying from immediately after the trauma to more than three decades later.⁹ Clinically, a patient with transdiaphragmatic intercostal hernia would typically present with a reducible, palpable soft tissue lump in the lower chest wall with a positive cough impulse. The swelling should increase on inspiration and decrease on expiration. A paradox change of the size of the hernia would suggest a pulmonary intercostal hernia.⁸ However, intercostal hernias may be mistaken for lipomas or hematomas,⁹ and high clinical suspicion, thorough patient history, and clinical exam are needed for the correct evaluation of the patient in clinically challenging cases.

The final diagnosis will be made following a CT scan that will confirm the intercostal herniation. Although ultrasound has also been useful in the diagnosis of such cases¹⁸ and offers a more affordable option than CT, it is almost deterministic that a contrast-enhanced CT will be needed preoperatively, in order to evaluate the contents of the hernia sac and rule out other pathologies, as well as to plan the appropriate surgical treatment.

If left untreated, an intercostal hernia could grow in size, or cause bowel or respiratory symptoms. Abdominal viscera strangulation, however, has been reported only in the presence of a concurrent transdiaphragmatic passage of hernia content.¹⁹ Apart of the complications of the hernia itself, a surgical repair could also be indicated because of cosmetic discomfort.

Most reported cases of intercostal hernias have been surgically managed by open surgical repair. Abdominal, thoracoabdominal, and thoracic approaches have all been used in order to access the hernia sac and repair the defect.^5,20 The abdominal approach is often used in trauma patients, as the mechanism of injury might be associated with concurrent intra-abdominal injuries. Conservative management might also be considered in asymptomatic patients or elderly patients with significant comorbidities.^15,21

The surgical management of intercostal hernias demands close attention to the damaged anatomy. The repair typically consists of reduction of the hernia contents, and obliteration or excision of the hernia sac. Currently, there is no consensus recommendation regarding the use of prosthetic mesh.²⁰ However, it has been reported that the nonuse of prosthetic reinforcement is associated with recurrence.²¹ Concurrent rib fractures are usually not stabilized, but cable banding around the ribs to counteract the dehiscence tension forces has also been suggested as a reliable method of repairing those hernias for which massive loss of chest wall integrity precludes endogenous repair.^4,22

The choice of the prosthetic mesh has not been unvarying between different authors reporting similar cases (Table 2). In general, polypropylene mesh, the most commonly used prosthetic material, carries a significant risk of cutaneous fistulas if placed directly over the viscera.²³ Thus, based on our concern for adhesions and the potential risk for fistula formation, we consider the insertion of a nonabsorbable mesh or a prosthetic patch (WL Gore & Associates, Inc.) a justified decision for our patient, since it would be in contact with the abdominal viscera. However, there is currently no evidence to support that the placement of ePTFE mesh is superior to polypropylene mesh as far as recurrence is concerned. Our patient remains recurrence-free 12 months after surgery and, although this is a relatively short period of follow-up, it is important to note that most recurrences in these types of hernias usually occur in the first few months.^24–26

Table 2 Summary of mesh choices for the repair of intercostal hernias containing liver segments

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Laparoscopic techniques, which are nowadays available in almost every field of modern surgery, have also been introduced in intercostal hernia repair. So far, there are 3 reports of laparoscopic repair of abdominal intercostal hernia: The first 2 were performed by Kurer et al.²⁴ in 2006 and Bobbio et al.² in 2008. In both these cases, the hernia contents consisted of omentum alone, suggesting the feasibility of an endoscopic approach in similar cases. Subsequently, Bendinelli et al.¹² reported an additional case of delayed laparoscopic repair of an intercostal hernia containing part of the liver. However, this patient presented with recurrence at 12 months postoperatively due to failure of the permanent tack (ENDOTACK; Karl Storz GmbH & Co., Tuttlingen, Germany) fixation.

In conclusion, intercostal hernia is a rare clinical entity that can develop either immediately following a trauma incident, or as a late complication. It should be suspected following high-impact blunt or penetrating injuries, and patients suffering such injuries should be followed up appropriately. A high clinical suspicion, along with a timely CT scan, will successfully set up the diagnosis of an abdominal or transdiaphragmatic intercostal hernia, which may contain different abdominal viscera. Surgical repair of the defect, with placement of a prosthetic mesh and with or without stabilization of concurrent rib fractures will warrant a favorable outcome.