Iliolumbar incisional hernia following iliac bone harvesting: a rare complication

Abstract

Incisional hernia is a common post-surgical complication, but hernias through iliac bone defects after the harvesting of an iliac bone graft is rare. The common presentation includes swelling and discomfort, and sometimes features of intestinal obstruction. A computerized tomography (CT) scan is commonly used for the diagnosis and to define the anatomical defect in the bone. Surgery is recommended because of high risk of strangulation. While various methods of repairing this type of hernia have been described, we chose to perform mesh repair for an iliolumbar incisional hernia.

Introduction

The iliac crest is a common donor site for bone in orthopedic and reconstructive surgery. ¹ The anterior iliac crest is the preferred site for bone harvesting, as it is easily accessible, and provides abundant cancellous bone. Complications have been reported following this procedure, among which one is herniation. To date, approximately 300 cases of lumbar hernia have been reported in the literature. ² Surgery poses a 10% risk of strangulation in the lumbar hernia. ² We report a case of iliolumbar incisional hernia presented in a 65-year-old female six years after an iliac bone harvesting.

Case report

A 65-year-old female presented with swelling in the left lumbar region for six years. She was operated on six years back, during which a bone graft was taken from her left iliac crest for a knee replacement. The patient also had dull aching pain at the site of the hernia. A physical examination revealed reducible swelling in the left lumbar region where the left iliac crest was, along with the scar from the surgery six years ago. The patient was diagnosed with an incisional hernia through the iliac crest. Laboratory investigations produced results within normal limits. A computerized tomography (CT) scan showed a defect in the left iliac crest (Figure 1) with a herniation of abdominal content (Figure 2). Surgery was performed with an oblique incision, to perform reduction of abdominal content by closing the defect with adjacent fascia (Figure 3). The surgery site was reinforced with the placement of a polypropylene mesh (Figure 4).

Figure 1.

CT scan showing defect in the left iliac crest.

Figure 2.

CT scan showing herniation of abdominal content through defect in left iliac crest.

Figure 3.

Operative photograph showing defect in the left iliac crest.

Figure 4.

Operative photograph of onlay mesh reinforcement following closure of defect.

Discussion

A lumbar hernia following an iliac crest bone graft harvesting is a rare complication which is more frequent in females than males. ¹ The incidence of hernia following iliac crest bone graft harvesting is approximately 5–9%. ² A lumbar hernia usually occurs when the full thickness of the iliac bone graft has been removed, or when there is a substantial defect after the bone graft harvesting.

Patients can develop symptoms from within a few days of the primary bone graft harvest to many years after the surgery. The lumbar area is a space bordered by: the lower edge of the twelfth rib superiorly, the iliac crest inferiorly, the erector spinae muscle and the lumbar spinous processes medially, and the external oblique muscle laterally. This area is divided into two compartments: superior (Grynfeltt hernia) and inferior triangle (Petit hernia). ³ The superior lumbar triangle is bordered superiorly by the twelfth rib, the lumbocostal ligament, and the serratus posterior inferior muscle, laterally by the internal oblique muscle, and medially by the erector spinae muscle. The inferior lumbar triangle includes the iliac crest inferior, the external oblique muscle laterally, and the latissimus dorsi muscle medially. In our patient, the hernia developed through the inferior lumbar triangle.

After an iliac crest bone graft harvest, the lumbar hernia may present with swelling over the iliac crest, as well as some discomfort. This may be associated with signs of intestinal obstruction. A CT scan is commonly used to confirm the diagnosis, and also to delineate the anatomy. ³ Repairing such hernias can be done by patching up the soft tissue, or by reinforcing the soft tissue with fascial flaps, bone transfer or mesh. The tension-free mesh repair can be performed with a laparoscopic, retroperitoneal or transabdominal approach. Attaching the mesh to the iliac bone is facilitated by suture bone anchors or corkscrew anchors. Another technique of soft tissue transfer involves using the transversalis fascia, abdominal musculature, and tensor fascia lata. Alternatively, the anterior superior iliac spine can be moved inferiorly and posteriorly to cover the defect in the iliac bone ³ . We chose to repair the hernia of the iliac crest defect using an extraperitoneal approach with an onlay mesh.

Lumbar hernia is a rare complication following iliac bone graft harvest. ⁴ Various surgical methods have been recommended to prevent such hernia. Ideally, harvesting the full thickness of the bone graft should be avoided. Instead, a partial thickness bone graft should be done if possible, to achieve similar results. Alternatively, the primary defect created following harvesting should be closed with mesh to prevent a lumbar hernia. The hernia developed in the post-operative period can be successfully repaired with mesh.