Traumatic abdominal intercostal hernia: A rare experience

Abstract

Traumatic abdominal intercostal hernias (AIHs) are an extremely rare surgical encounter, with amorphous literature. A case report of recurrent AIHs, evident only at surgery, and its management is presented. The inadequacy of experience and data translates to frequent missed diagnosis and suboptimal surgical management with high recurrence rates.

Introduction

Abdominal intercostal hernias (AIHs) occur when intercostal muscle and fascial disruption allows herniation of abdominal contents between the ribs. Exceedingly rare entities with scarce literature, a recent systematic English literature review, yielded only 20 cases, and available information is gleaned from scattered reports.¹ A successfully managed case of recurrent AIH following gun shot injury is presented and discussed in this report.

Case report

A 39-year-old male sustained a shotgun wound over his right upper abdomen on 30 June 2011. Exploratory laparotomy revealed multiple splinter injuries to the ascending colon wall with a large intramural haematoma. Splinter retrieval, bowel wall repair and loop ileostomy were performed. Postoperatively, the patient developed surgical site infection and a recurrently discharging sinus. Computed tomography (CT) Scan in February 2012 revealed underlying rib osteomyelitis which required debridements followed by rib segment excision. The problem continued to fester with limited debridements proving ineffective. A repeat CT scan revealed lower sternal osteomyelitis for which partial sternectomy was performed in October 2012. The resultant large thoracoabdominal wound was managed with vacuum-assisted closure, and the wound eventually healed over 2 months. He however developed an incisional hernia at the operative site (Fig. 1B). Open mesh hernioplasty and thoracoepigastric flap cover was performed in October 17. Intraoperatively, considerable difficulty was encountered in defining the planes due to fibrous tissue and dense adhesions as a result of pervious surgeries and osteomyelitis. He had an uneventful postoperative recovery. He resumed duties but noted recurrence of the hernia after 6 months and reported back. Ultrasound revealed a 10-cm with bowel herniation in the right epigastric region. CT scan revealed a right rectus sheath defect of 7.6 × 6.4 cms, with herniation of the omentum and small bowel (Fig. 2A and B). Exploration under general anaesthesia was through flap elevation. The wide mouth hernia defect was defined, and the intact sac reduced into the abdomen without opening it (Fig. 2C). On dissection of the defect margins, it was found to lie between the 9th and 10th rib and costal cartilages. The 10th rib cartilage was stretched, thin and irregular, forming the clinically palpable lower taut margin. Patient consent was obtained for images and inclusion in the study.

Fig. 1.

(1A) Flap cover over the hernia (initial hernia repair). (1B) Preoperative image with intercostal hernia. (1C) Postoperative image of anterior view. (1D) Postoperative image of lateral view.

Fig. 2.

(2A) Image of the lower chest and abdomen with retained gun shot pellets. (2B) Axial image of the upper abdomen with intercoastal defect and herniating bowel loops. (2C) Intraoperative image showing defect. (2D) Intraoperative photo with the mesh covering the defect.

Although possibility of approaching the hernia laparoscopically was considered, we concluded that it would in all probability be unsuccessful, considering the multiple previous surgeries, deformed anatomy and the placement of mesh during the previous repair. Anchoring of the mesh laparoscopically to overlap the defect cranially would also not have been feasible. We proceeded with open repair. With previous history of multiple interventions and stoma, it was decided to avoid opening or dissecting the sac widely off the margins. Two other areas of fascial weakness were found off the midline.The wide intercostal gap was bridged by intercostal no. 2 loop nylon sutures. Multiple interrupted sutures approximated the ribs to an inch, creating an intercostal mesh and effectively repairing the defect. Because there were two more midline sites of potential herniation, a polypropylene onlay mesh was placed across the bridged intercostal space and the two defects and up to 5 cm beyond (Fig. 2D). A few wide irregular scars were excised for uniform closure, and the thoracoepigastric flap was reinset over closed suction drainage. In view of the intercostal nature of the defect and the lack of soft tissue and muscles and dense fibrous tissue around the hernia, any kind of component separation techniques was not feasible. The patient had an uneventful postsurgical course and was discharged on the 10th postoperative day. Review at 12 weeks revealed no evidence of weakness clinically or radiologically (Fig. 1C &D).

Discussion

Intercostal hernias include subtypes with thoracic, abdominal or transdiaphgramatic defects. Abdominothoracic rib cage hernias are extremely rare. In true AIHs, intraperitoneal contents directly herniate through the intercostal space, the diaphragm remaining intact. Herniated content may be the liver, colon, small gut or omentum.²

AIHs are commonly posttraumatic; the mechanism being blunt, penetrating or postsurgical trauma in 85% of cases. Other AIH subtypes are the rare spontaneous occurrences or those subsequent to abdominal wall pathology. Only 20 cases of acquired AIHs were reported by Erdas et al¹ in a systematic review in 2014, including their own report. Any defect in the diaphragm excludes the diagnosis of acquired AIHs and is classified separately as a transdiaphragmatic intercostal hernia.³ Causative factors implicated in acquired AIHs are a dual combination of weak walls and intraabdominal pressure. The rarity and variety of AIHs have resulted in few attempts at classification and management protocols. Erdas et al¹, in a systematic world literature review in 2014, identified 20 cases of acquired AIHs. They reported a mean age of 58.4 years (27–88) with a male:female ratio of 1.8:1 and identified predisposing risk factors in 85% cases. Military wounds by high velocity gunshots or splinters result in significant tissue damage and loss. Polytrauma, tissue loss, foreign bodies, multiple emergency surgeries and infection predispose to abdominal wall weakness, and our patient had all. AIHs are reported to present from within days to decades after the original injury, most arising from under the 9th rib, with no distinct side predominance. Our patient noted the hernia two years after the injury. Mesh hernioplasty was followed by a recurrence after 6 months. Imprecise diagnosis of AIHs is reported in up to one-fourth cases and may have been so in our case too.

Diagnosis is clinical and CT affords an excellent diagnostic tool, but both failed to yield complete knowledge of the recurrent hernia boundaries. Our patient had a wide mouth hernia which was spontaneously reducing (Fig. 1B) but incarceration and obstruction of the bowel can occur in up to 15% of cases.¹ Surgical approach is commonly a standard open thoracotomy, which gives a rapid and easy access to the sac, allowing preperitoneal mesh placement.

Laparotomy or a laparoscopic approach, although indirect, affords access to hernia contents, an essential need when dealing with compromised contents.

Combined open rib approximation and laparoscopic hernioplasty approaches offer minimal advantages. Rib approximation was used in nearly half the 20 reported cases of AIHs. Critics cite severe postoperative and chronic pain attributed to intercostals nerve strangulation as reason to avoid rib approximation. Proponents advise rib approximation in wide defects for reinforcing the repair, provided intercostals nerve damage is avoided.^4,5

We used strong non-absorbable intracostal no. 2 loop nylon sutures to bridge the wide intercostal defect rather than the pericostal sutures.⁶ Our patient had a smooth postoperative course with no significant pain and was ambulant from the postoperative evening.

Tension-free hernioplasty is the standard of care in hernia repair. Various approaches, planes, prosthesis and fixation methods are in vogue, but recurrences in AIHs are high, recorded at 28.6% at the 8.6-month follow-up. Our patient had suffered a shotgun injury and had undergone 5 previous surgeries, including one for incisional hernia. The true intercostal nature of the abdominal hernia was discovered at surgery for recurrence. Intracostal rib approximation and onlay prolene mesh repair were used. Follow-up at 3 months revealed a secure repair both clinically and on ultrasound.The patient is on regular follow-up. Awareness of this rare condition and data sharing would add to the information base leading to improved guidelines for care.

Disclosure of competing interest

The authors have none to declare.