Lumbar, Pelvic, and Uncommon Hernias

Anatomy and Classification

Lumbar hernias are exceedingly rare, posterolateral, abdominal wall defects containing retroperitoneal fat or viscera. Lumbar hernias were first described several hundred years ago. Barbette suggested the entity of a lumbar hernia in 1672, but the first published case in the medical literature was in 1731 by DeGarangeot. He reported the first incarcerated lumbar hernia on autopsy. Twenty years later, Ravaton described the surgical reduction of a strangulated lumbar hernia. The French surgeon Jean-Louis Petit in 1774 was the first to describe an inferior lumbar hernia through the anatomic boundary now often referred to as Petit triangle. More than two centuries after its first description, Grynfelt and Lesshaft independently reported visceral herniation through a superior lumbar defect, now commonly known as a Grynfelt-Lesshaft hernia.

Lumbar hernias occur through a parietal wall defect in the lumbar region whose boundaries are the 12th rib superiorly, the iliac crest inferiorly, the erector spinae muscle medially, and the posterior border of the external abdominal oblique laterally ( Fig. 54.1 ). They can be classified anatomically into superior or inferior lumbar hernias based on two well-defined areas of weakness. The superior lumbar triangle is an inverted triangle bordered by the 12th rib superiorly, the internal abdominal oblique muscle anterolaterally, and the quadratus lumborum muscle posteromedially. The latissimus dorsi and the aponeurosis of the transversalis muscle form the roof and the floor of the triangle, respectively. Areas of weakness include the region immediately below the costal margin where the transversalis fascia is not reinforced by the external abdominal oblique muscle, the area at which the 12th dorsal intercostal neurovascular bundle penetrates the fascia, and the area between the ligament of Henle and the inferior costal margin ( Fig. 54.2 ). The inferior lumbar triangle, or Petit triangle, is an upright triangle bordered by the iliac crest inferiorly, the external abdominal oblique muscle anterolaterally, and the latissimus dorsi posteromedially. The floor is formed by the lumbodorsal fascia and transversalis muscle. A medially displaced latissimus dorsi muscle, alterations in the origin of the external abdominal oblique muscle, and the presence of a Hartmann fissure at the vertex of the triangle may increase the likelihood of visceral protrusion through the inferior lumbar triangle ( Fig. 54.3 ). Herniation occurs more commonly in the superior triangle as it has a greater surface area, is a more vulnerable area of weakness (there is only transversalis fascia at its lower margin), and is not penetrated by neurovascular bundles.

In addition to the anatomic classification, lumbar hernias can further be categorized as congenital or acquired based on etiology. Congenital defects of the lumbar region make up 10% to 20% of lumbar hernias. Although often unilateral when presenting early in life, some patients may have bilateral hernias and develop symptoms in late adulthood as a result of progressive posterolateral abdominal muscle weakening. Congenital lumbar hernias are most often associated with lumbocostovertebral syndrome, although it has been reported with vertebral anomalies, anal atresia, cardiac defects, tracheoesophageal fistulas, renal anomalies, and limb defects (VACTERL syndrome), congenital diaphragmatic hernia, and atrial septal defects, among other congenital malformations.

Acquired lumbar hernias constitute the majority of lumbar defects encountered clinically and can be subdivided into primary or secondary acquired hernias. Primary acquired hernias occur spontaneously, are often small in size, are confined to the borders of the superior or inferior lumbar triangles, and represent 55% of acquired lumbar hernias. Risk factors for the development of a primarily acquired lumbar hernia include advanced age, chronic malnutrition or debilitation, obesity, chronic cough, and previous wound infections or a history of sepsis. On the other hand, secondary acquired hernias are often the result of trauma or previous surgical procedures in the lumbar region. These defects may be diffuse, extending beyond the margins of the lumbar triangle. It is a rare complication of surgical procedures involving flank incisions. Examples include open partial or complete nephrectomy, adrenalectomy, and abdominal aortic aneurysm repair. It may also occur at previous bone graft donor sites. The iliac crest is a common donor site for autogenous bone grafts given that it is easily accessible and supplies ample amounts of both cancellous and cortical bone. Herniation of intraabdominal contents through the resulting bone defect is uncommon, occurring only in up to 5% of cases. Blunt trauma is another rare cause of secondary acquired lumbar hernias, with less than 100 cases reported in the literature. Traumatic lumbar hernias (TLHs) occur more commonly through the inferior lumbar triangle, and repair is often complex and challenging because there may be destruction of the surrounding muscle, leaving inadequate muscle or aponeurotic tissue for fascial reapproximation.

Clinical Presentation and Diagnosis

Patients usually present with a small protruding mass in the lumbar region that may be symptomatic or asymptomatic. The majority of patients are males in their fifth or sixth decade of life. The differential diagnosis includes but is not limited to a lipoma, rhabdomyoma, sarcoma and other malignant growths, abscess, hematoma, or a renal mass. Pain is variable and can range from mild local discomfort to severe, diffuse intestinal colic. Depending on the contents of the hernia, the pain can travel downthe distribution of the sciatic nerve or be referredto the anterior abdomen, especially when incarceration or panniculitis is present. Patients may also have gastrointestinal complaints such as nausea, vomiting, and/or bloating. When a mass is palpated in the lumbar region, it is often soft and fluctuates in size. In addition, the mass may protrude with coughing or bearing down and even produce bowel sounds on auscultation based on the contents of the hernia. Lumbar hernias may contain retroperitoneal fat, small and large intestine, omentum, appendix, stomach, cecum, ovary, spleen, and rarely the kidney. Urinary obstruction or oliguria may be the presenting symptoms in patients having renal contents within the hernia sac. Pain in the lumbar region accompanied by the signs and symptoms of intestinal obstruction is suggestive of an incarcerated or strangulated lumbar hernia.

Although the diagnosis can be made upon physical exam in the majority of cases, lumbar hernias may be less apparent when the hernia defects are smaller than 5 cm in diameter. Computed tomography (CT) ( Fig. 54.4 ) is the preferred diagnostic modality in patients who present with signs and symptoms concerning for a lumbar hernia. It can provide useful information about the size of the fascial defect and allow for the assessment of hernia sac contents and regional anatomic relationships. Magnetic resonance imaging (MRI) may also be performed to confirm the diagnosis of a lumbar hernia. Ultrasonography is an alternative imaging modality that may be more appropriate in emergency settings. Although less accurate than CT in depicting anatomy, it is fastidious, less costly, effective, and does not expose the patient to ionizing radiation. The diagnosis can be made with visualization of a hernia orifice in the posterolateral abdominal wall, which will appear as a defect in the echo line of the aponeurosis. When identification of this orifice is difficult, the presence of a hernia may be suggested by the finding of an intraparietal sac or presence of abdominal contents. On ultrasound, this may be indicated by intraluminal gas, which projects as an area of focal dense echogenicity with acoustic shadowing.

Treatment

The natural progression of lumbar hernias is a gradual increase in size over time. Despite this, approximately 25% of patients will present with incarcerated bowel, and 10% to 18% will demonstrate evidence of strangulation. Given the risk of associated complications and the increased complexity of repairing large hernias, surgical intervention upon diagnosis of a lumbar hernia is prudent when the patient's medical condition permits. The repair of a lumbar hernia is challenging, and various techniques of repair have been described, including simple repair, musculofascial flaps, free grafts, and repair using synthetic mesh. More recent studies have evaluated the efficacy of laparoscopic or retroperitoneoscopic repair. Still, the rarity of lumbar hernias and lack of sufficient data preclude a standardized approach or optimal timing in the management of this condition.

Lumbar hernias are traditionally approached through an open or anterior technique. In this approach the patient is placed in a lateral decubitus position contralateral to the side of the hernia. General or spinal anesthesia may be used based on the surgeon's discretion. A generous lumbar incision is made, and exploration of the hernia is performed ( Fig. 54.5A ). The edges of the fascial defect are defined circumferentially. After the hernia sac is identified and its contents reduced, the sac may be excised or inverted. If the defect is small, it may be repaired primarily with nonabsorbable sutures (see Fig. 54.5B–D ), although larger defects require a mesh-enforced repair with reapproximation of the overlying muscle layers. Nonabsorbable mesh may be secured in an extraperitoneal position with 3 to 5 cm of overlap. In a case series by Cavallaro et al., seven patients with both Petit- and Grynfelt-type hernias underwent open repair with placement of an extraperitoneal mesh. They reported no recurrences over a median of 25 months. Synthetic mesh was secured to the surrounding muscles and the 12th rib or iliac crest for superior and inferior defects, respectively. Solaini et al. described a separate case of open repair of a superior lumbar hernia with dart mesh (Bard Mesh Dart, a small monofilament knitted polypropylene) fixed to the 12th rib. The mesh was fixed medially to the quadratus lumborum, externally to the internal oblique, and inferiorly to the serratus posterior. The patient was discharged on the first postoperative day and did not demonstrate a recurrence at 11 months of follow-up. The open or anterior approach may be preferable when the lumbar defect is small and well defined with adequate surrounding musculoaponeurotic tissue. Interestingly, simple primary closure of lumbar hernias without mesh has demonstrated acceptable outcomes over a short follow-up period. However, most authors agree that mesh reinforcement is an important component in ensuring the durability of the repair, particularly for larger hernia defects.

The alternative to open repair is a laparoscopic repair. The laparoscopic technique may be performed through a transabdominal or retroperitoneoscopic approach. In the transabdominal approach, patient positioning is similar to that of the open approach. A lumbar roll may be placed to increase the distance between the inferior rib margin and the iliac crest. Dissection occurs along the white line of Toldt. The colon is mobilized and the borders of the underlying lumbar defect are identified ( Fig. 54.6 ). The hernia sac and its contents are reduced. Mesh may then be secured with transabdominal full-thickness bites using a combination of nonabsorbable sutures and tacks ( Fig. 54.7 ). The use of bone anchors has been described to secure mesh to the iliac crest in inferior lumbar hernias. In a study of seven patients who underwent laparoscopic transabdominal incisional lumbar herniorrhaphy with polypropylene mesh reinforcement, there were no complications or recurrences over a mean follow-up of 34 months. The laparoscopic transabdominal approach may also be preferable in patients with previous lumbar surgery.

Unlike the transabdominal laparoscopic technique, the retroperitoneoscopic (or totally extraperitoneal [TEP]) repair avoids penetration into the abdominal cavity. A flank incision is made and a balloon dissector is used to create a retroperitoneal plane and adequate operating space. Nonabsorbable mesh is placed in an extraperitoneal position. Habib reported no recurrence out to 2 years in a patient who underwent tension-free retroperitoneoscopic repair of a superior lumbar hernia with polypropylene mesh.

The management of TLH deserves special mention. The timing of the repair (early vs. delayed) and the surgical approach to those patients with TLH require individualization based on the patient's clinical status, presence of concomitant injuries, mechanism of injury, size of hernia, patient factors, and radiologic findings. Early repair is recommended in hemodynamically stable patients without major associated injuries. In patients with extensive tissue loss and contamination, it is preferable to defer hernia repair until life-threatening injuries such as visceral injury have been addressed. A transperitoneal approach is recommended by some authors in TLH to evaluate for concomitant bowel injuries. In a case series by Chan et al., of four patients presenting with lumbar hernias following blunt trauma, two patients underwent delayed repair with mesh via a lumbar incision, one patient underwent a laparoscopic transabdominal mesh repair, and the last patient had an open transabdominal mesh repair. In all of the patients, the mesh was placed in an extraperitoneal sublay position. There were no recurrences in their study, although one patient was lost to follow-up. A polytetrafluoroethylene or PTFE (Gore-Tex) tissue patch can be used for the coverage of large defects. It can also be used in the face of contamination because it is biologically inactive leading to decreased inflammation and adhesion formation, has good tensile strength, and may be resistant to infection.

Although the laparoscopic transabdominal and retroperitoneoscopic approaches require less tissue dissection and provide an improved anatomic view in comparison to the open technique, there is no consensus regarding the preferred approach to lumbar hernias. Moreno-Egea et al. performed the only reported comparative study of open versus laparoscopic lumbar hernia repair. They demonstrated that a laparoscopic technique provides advantages such as decreased morbidity and length of stay, with quicker return to normal activity and no significant increase in cost. A classification system has been proposed to help guide the management of lumbar hernias, which classifies them into four categories based on six individual criteria: size, location, contents within the hernia, the presence of muscular atrophy, origin, and a history of recurrence. Although this classification system has yet to be validated, it may provide a basis to aid in the clinical management of lumbar hernias.