Post traumatic lumbar hernia.AI Sarela, AA Mavanur, AA Bhaskar, ZF Soonawala, GG Devnani, HK Shah, AB Samsi
Department of General Surgery, KEM Hospital, Mumbai.
Correspondence Address: Source of Support: None, Conflict of Interest: None PMID: 0009715322
Source of Support: None, Conflict of Interest: None
A lumbar hernia which had developed following blunt abdominopelvic trauma is described here. The successful surgical correction is reported.
Keywords: Abdominal Injuries, complications,Case Report, Female, Fractures, complications,Hernia, diagnosis,etiology,surgery,Human, Lumbosacral Region, Middle Age, Pelvic Bones, injuries,Wounds, Nonpenetrating, complications,
Lumbar hernias occur in the quadrilateral that is bounded above by the 12th rib, below by the iliac crest, behind by the erector spinae muscle and in front by a vertical line drawn from the tip of the 12th rib to the iliac crest. This area encompasses the 2 anatomical triangles, which form the commoner sites for lumbar hernias. The inferior lumbar triangle (Petit's) is bounded by the posterior free margin of the external oblique muscle in front, the Latissimus dorsi behind and the iliac crest below. The floor is formed by the internal oblique muscle and the lumbar fascia. The superior lumbar triangle (Grynfeitt-Lesshaft's) is bounded above by the 12th rib and the sacrospinalis muscle, behind by the erector spinae group and in front by the internal oblique. The Latissimus dorsi forms the roof of the triangle.
The aetiology of a lumbar hernia may be congenital (maldevelopment or malformation of musculoskeletal structures) or acquired. The spontaneously acquired variety may represent either a delayed presentation of the congenital variety or may be due to weakening of the muscle layers and various straining factors (as in the commonly seen inguinal hernia). In addition, about 25% of all lumbar hernias have a traumatic aetiology,. This may, be post-surgical, such as a flank incision to approach the kidney, harvesting a bone graft from the iliac crest or fashioning a Latissimus dorsi flaps. Lumbar hernias may also follow blunt or penetrating injuries to the flank. Blunt injuries may be associated with a significant disruption of the flank musculature, pelvic fractures and flank hematomas. In consequence, the resulting hernia may be large and not conform to the anatomical boundaries of the lumbar region. It may be also associated with intra-abdominal injuries. The management of such patients constitutes a surgical challenge.
We are reporting the case of a lady who presented to us with a lumbar hernia, 2 years following a blunt abdominopelvic injury.
Mrs. D, a 45 year old lady, presented with a reducible swelling measuring about 8 cm x 10 cm in the left lumbar area. She had initially noticed the swelling about 1 and ½ years ago, while she was convalescing from a railway accident. A detailed medical history of this event was not available, but she had apparently suffered from hypovolemic shock, multiple rib fractures, pelvic fractures and a left intertrochanteric femur fracture. She was transfused blood, infused crystalloids and drugs and advised 3 months bed rest. Following this accident, she had developed a tender swelling in the left flank, which subsequently assumed the characteristics of an acute abscess and ruptured spontaneously. It was surgically drained, but a sinus persisted at the site. Following this event, she then developed a progressively enlarging left lumbar swelling which displayed all the characteristics of a hernia.
On investigations, she was discovered to be a hypertensive and a diabetic. A swab taken from the sinus grew Staphylococcus aureus: Plain roentgenograms of the pelvis showed an old fracture of iliac crest with a missing triangular shaped segment. A barium study showed that the hernia sac contained the sigmoid colon and a loop of small bowel. A normal IVU was obtained.
She was scheduled for surgery after controlling her medical problems and adequately preparing the large bowel. Under general anaesthesia, she was placed in the right lateral position. A sigmoid shaped incision, extending from the left renal angle to the left anterior superior iliac spine, was made. The hernia was discovered to contain fat and a large peritoneal sac with a sliding hernia of the sigmoid colon. The margins of the defect were formed by the 12th rib above, the iliac crest below, the external oblique muscle in front and the erectors spinae behind. The redundant sac was excised and then suture closed with 1-0 prolene. A prolene mesh was fashioned as an inlay prosthesis and fixed to the margins of the defect with multiple 2-0 prolene horizontal mattress sutures. Suction drain tubing was placed on the mesh and the wound was closed in layers.
The immediate postoperative period was uneventful. On the 5th postoperative day, signs of infection were noted at the anterior end of the wound. Multiple skin sutures were removed and the wound healed well with daily dressings.
Lumbar hernias are rare, with less than 300 cases reported in the literature. It is possible that a number of patients go undiagnosed because they are either asymptomatic or present with vague complaints such as lower back pain. The diagnosis is particularly elusive in obese individuals or in post-surgical patients in whom the classical presentation of a reducible flank swelling, which imparts an expansible impulse on coughing, is uncommon. In such a situation, a long standing hernia is apt to be mistaken for lipoma, a fibroma, a retroperitoneal tumour or a chronic abscess.
An entity, which is less well known, and consequently more likely to be missed is an acute lumbar hernia. This is a rare, but significant, abnormality that should be considered in patients with blunt abdominal trauma, specially in those with large flank hematomas and pelvic fractures. In a series of 850 patients who underwent abdominal CT scanning in acute abdominal trauma, an acute lumbar hernia was diagnosed in 7 patients. A tender flank swelling discovered on clinical examination of such patients is usually considered to be a flank hematoma, unless the possibility of a lumbar hernia is entertained and CT scanning is performed.
As the diagnosis is usually difficult to confirm by purely clinical means, imaging modalities become necessary. A small and large bowel barium study has been recommended to determine which portion of the bowel, if any occupies the hernia. In addition an IVU may be performed to visualise any displacement of the kidney or ureter into the hernia. However, recent reports suggest that an abdominal CT scan is probably the most valuable imaging modality. A CT scan can accurately distinguish the muscular and fascial layers, detect the presence of a defect in these layers, visualise herniated fat or viscera and differentiate a hernia from a hematoma, abscess or soft-tissue tumour,. USG has also been reported to be useful in imaging a lumbar hernia.
A lumbar hernia should be repaired surgically, as it is prone to both obstruction and strangulation. In addition, an abscess has been reported to complicate an acute lumbar hernia. This may be due to injury to the contained bowel. The various surgical techniques, which have been described include anatomical approximation of the muscles and fascia and the use of musculofascial flaps and prosthetic meshes to fill the defect. The surgical anatomy of these hernias deserves emphasis The hernia may be extraperitoneal (herniation of viscera with no peritoneal covering), paraperitoneal (herniation of viscera accompanied by an adherent portion of peritoneum following the descent of the hernia), or complete intraperitoneal (the peritoneum covers the hernia completely forming a true hernial sac). The contents of the hernia may be fat, omentum, sigmoid colon, caecum, appendix small bowel, stomach or kidney.
In conclusion, both acute and long-standing lumbar post-traumatic lumbar hernias are rare but challenging conditions, which require an appropriate index of suspicion and investigations for diagnosis and a well planned surgical repair.