Traumatic abdominal wall hernia

Abstract

INTRODUCTION

Traumatic abdominal wall hernia (TAWH) is a rare entity. Most cases occur in children, following an injury from the bicycle handle bar. In adults, it usually results from road traffic accidents (RTA). We present one of the largest reported cases of TAWH following RTA managed by delayed mesh repair.

PRESENTATION OF CASE

A 35 yr old obese male with RTA was diagnosed with TAWH with 19 cm × 15 cm defect in left flank. As there were no intra abdominal injuries and overlying skin was abraded, he was planned for elective repair after 6 months. On exploration a defect of 30 cm × 45 cm was found extending from midline anteriorly to 8 cm short of midline posteriorly in transverse axis and costal margin to iliac crest in craniocaudal axis. After restoration of bowel into abdominal cavity, primary closure or even approximation of muscular defect was not possible thus a mesh closure using 60 cm × 60 cm prolene mesh in subcutaneous plane was done. After 4 months follow up, patient is healthy and has no recurrence.

DISCUSSION

Emergent surgical management of TAWH is usually favoured due to high incidence of associated intra abdominal injuries. Delayed repair may be undertaken in selected cases.

CONCLUSION

TAWH, although rare, should be suspected in cases of RTA with abdominal wall swellings. With time, the hernia defect may enlarge and muscles may undergo atrophy making delayed repair difficult.

1. Introduction

Traumatic abdominal wall hernia (TAWH) is a rare entity and is caused by blunt trauma to the abdomen. Although, TAWH was first described by Selby¹ a century ago, fewer than 100 cases have been reported in English literature. TAWH is defined as “herniation through disrupted musculature and fascia, associated with adequate trauma, without skin penetration and no evidence of a prior hernia defect at the site of injury”.² Skin can be bruised but normally remains intact. Most TAWH are diagnosed on presentation with contrast enhanced computed tomography of abdomen and most authors advocate immediate laprotomy in view of high incidence of intra-abdominal injuries. We present one of the largest reported cases of TAWH managed by onlay meshplasty, 6 months after initial trauma.

2. Case presentation

A 35 yr old obese male, presented to emergency after road traffic accident (hit by a car while driving a two-wheeler). He was conscious, oriented and complained of left sided abdominal pain. On examination his pulse was 102/min and blood pressure was 126/74 mm Hg. Initial survey of the abdomen revealed a large swelling over left flank extending over to left hip joint with abrasion and ecchymosis of the overlying skin. The swelling was tender but was soft and cystic. There was no guarding or rigidity over the abdomen. Examination of all other systems was unremarkable. An initial diagnosis of subcutaneous haematoma was made and patient was assessed further.

His haemoglobin was 10.6 gm/dl and rest of the haematological and coagulation profiles were within normal range. Skeletal survey did not reveal any bony injury. Focussed ultrasound of the abdomen revealed mild amounts of free fluid in abdominal cavity. As the patient was haemodynamically stable, he underwent a contrast enhanced computed tomography (CECT) which revealed a complete tear of left anterolateral abdominal wall musculature with a defect of 19.5 cm in vertical and 15 cm in anteroposterior axis. Small bowel loops occupied subcutaneous plane up to the level of hip joint. A final diagnosis of TAWH with large defect was made (Fig. 1).

Fig. 1.

Initial CECT showing hernial defect.

In view of a large defect which would have resulted in difficult primary closure, unhealthy overlying skin with abrasion and haematoma and reluctance to use of mesh in emergency surgeries because of infectious complications, a decision was made to observe the patient and post for elective surgery once the overlying skin got healed.

After 6 months, the overlying skin got healed and patient lost 15 kg of weight but the hernia increased in size. The palpable defect was bigger with well defined margins and the sac now reached up to the knee joint (Fig. 2). Patient was taken up for surgery as he complained of poor quality of life and inability to work because of the hernia. He also complained of continuous dragging pain which we ascribed to the pull of small bowel mesentery which was a content of this hernia. Patient was positioned in right lateral position and with a transverse incision overlying the defect, the peritoneum was opened. A muscular defect of 30 cm × 45 cm was found extending from midline anteriorly to 8 cm short of midline posteriorly in transverse axis and from costal margin to iliac crest and inguinal ligament in craniocaudal axis was present. Defect was lined by rectus muscle in the anterior midline, erector spinae muscle posteriorly, costal margin cranially and iliac crest and inguinal ligament caudally. Rectus muscle of ipsilateral side was atrophied and was pulled to opposite side. The oblique muscles were also atrophied and lined the margins of the defect. Through this defect, in the subcutaneous plane overlying the erector muscles of the back and gluteal and quadriceps muscles of the thigh, there was a peritonealised hernial sac containing loops of small bowel and clear straw coloured fluid (Fig. 3). This sac extended from costal margin above to knee joint below and vertebral column posteriorly to communicate with peritoneal cavity anteriorly through muscular defect. There was no way to close or even approximate this defect. Thus, a peritoneal flap with some amount of subcutaneous tissue was raised at upper margin of the incision up to the costal margin. Margins of this flap were sutured to margins of the muscular defect so as to close the peritoneal cavity separating it from the subcutaneous hernial sac. The peritoneum of hernial sac was scrapped and approximated to each other. A 60 cm × 60 cm prolene mesh was placed above the flap and sutured to the margins of the defect (Fig. 4). The overlying skin approximated after inserting several suction drains. Thus we were able to close the muscular defect with help of a mesh and manage to place peritonealised flap between bowel and mesh.

Fig. 2.

Showing large hernia (compare with initial CECT).

Fig. 3.

Intraoperative photograph showing hernial sac.

Fig. 4.

Intraoperative photograph showing prolene mesh being fixed.

Patient was nursed in intensive care settings for 3 days. On 4th post operative day he developed superficial skin necrosis at the upper margin of the suture line which healed by secondary intention. On 12th post operative drains were removed and gradual mobilisation started. Patient was discharged in healthy condition.

After 4 months of surgery, clinical and CECT examination do not reveal any recurrence or a residual defect and mesh is in place in subcutaneous tissue (Fig. 5). Patient is free of his symptoms although there is a visible bulge in left flank as compared to opposite side.

Fig. 5.

Postoperative photograph.

3. Discussion

Although blunt trauma is common, TAWH remains rare. It involves application of blunt force to the abdomen over an area large enough to prevent skin penetration. These tangential forces cause pressure induced disruption of abdominal wall muscles and fascia and result in a hernia.³ As skin is more elastic than other layers it remains intact. Most TAWH follow high velocity vehicle accidents, seat belt or handle bar injuries. Herniation is seen at anatomically weak points due to blow out and not at site of injury.⁴ TAWH usually occur either lateral to the rectus, in lower abdomen or in inguinal region.

Wood et al. classified TAWH in 3 major types: type I are sustained from high energy injuries and are commonly associated with intra-abdominal injuries. Type II occurs due to low energy injuries example handle bar hernias. Type III result from deceleration injuries and are associated with intra abdominal herniation.⁵

Although TAWH usually present as tender palpable lump with ecchymosis of overlying skin, CECT scan is the most accurate diagnostic tool.⁶ It can define the anatomy of disrupted abdominal wall, differentiates hernia from haematoma and identifies intra abdominal injuries.

Surgery is primary modality of treatment which can be emergent or delayed. Probability of intra-abdominal injuries plays the most important role in deciding the timing of operative intervention. Immediate exploration with hernia repair is generally accepted as favourable choice as it allows to rule out any intra abdominal injury and prevents strangulation of herniated bowel which may occur hours to days after injury.^7,8 The period of hospitalisation and disability is also shortened. But debridement of devitalised tissue may be required and placement of mesh is contraindicated due to fear of infectious complications. Most authors have reported immediate exploration with layer-by-layer closure of defect with or without mesh as the preferred procedure.

Patients with large defects (low chances of strangulation) and no intra-abdominal injuries, as in this case, can be managed by delayed elective repair.^9,10 Surrounding tissue will be healthy and mesh can be used. However, as in this case, the defect may enlarge with time and muscles undergo disuse atrophy thus primary approximation may be difficult.¹¹ Also large hernias if repaired under tension may cause abdominal compartment syndrome.

Best incision, suture material to be used and the role of mesh are also debatable issues. In emergency settings, one may prefer midline incisions as exploration of intra-abdominal injuries is easier and defect can be repaired from inside.⁹ However in elective cases, as in present case, an incision overlying the defect is preferred.¹² Choice of suture material depends on surgeon's preference and most authors advocate use of non absorbable monofilament for repair of the defect.³ Mesh is usually preferred if defect is large or musculature is weak¹² but layer by layer closure without tension also provides acceptable results.¹³ Use of mesh is contraindicated in patients with associated bowel perforations or necrotic tissue due to chances of infectious complications.

Thus, there is no defined protocol for surgical management but most authors advocate emergency exploration using midline incision and repair with non absorbable suture and mesh.

4. Conclusion

TAWH, although rare, should be suspected in all cases of high velocity injuries with abdominal wall swellings and CECT should be used for accurate diagnosis. Emergency midline exploration with examination of abdominal contents and repair of hernia with non absorbable sutures with or without use of mesh is favoured. Delayed repair may be considered in selected cases but the hernia may enlarge and defect may widen over time, making repair technically demanding and exhaustive. Thus, TAWH are best managed on a case by case basis.

Conflict of interest statement

The authors have no conflicts of interest.

Funding

None.

Ethical approval

Written informed consent was obtained from the patient for publication of this case report and accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal on request.

Author contributions

Siddharth Yadav – prepared the manuscript, assistant in surgery.

Sunil K. Jain – chief operating surgeon, proof read the manuscript.

Jainendra K. Arora – assistant in surgery, proof read the manuscript.

Piyush Sharma – helped in preparing the manuscript.

Abhinav Sharma – helped in preparing the manuscript.

Jai Bhagwan – helped in preparing the manuscript.

Kaushal Goyal – helped in preparing the manuscript.

Bhabani S. Sahoo – helped in preparing the manuscript.