IMPORTANCE OF AN INTACT ABDOMINAL MUSCULATURE MECHANISM IN MAINTAINING SPINAL SAGITTAL BALANCE: CASE STUDY IN PRUNE-BELLY SYNDROME

Abstract

Ongoing debate exists as to the integrity of the abdominal musculature unit in maintaining spinal support and stability. It is thought that the intra-abdominal pressure generated is important in spine stabilisation. Congenital aplasia of the abdominal musculature, i.e. prune belly syndrome (PBS), might therefore result in loss of spinal function and stability. We discuss the possible role of an intact abdominal musculature mechanism in maintaining spinal saggital balance and its relevance to low back pain with this case illustration of PBS. We also review the literature for the incidence of spinal deformities related to PBS.

We present a unique case of a 33-year-old male with PBS that resulted in loss of spinal saggital balance and development of a thoracic hypokyphotic deformity and thoracolumbar scoliosis. The patient also suffered from mild low back pain. Literature review suggests that secondary scoliosis appears to be the most commonly reported spinal deformity with up to 36% of cases being affected in one study.

Unequal compressive forces on the vertebral end-plates as a result of changes in static rib support, dynamic paraspinal muscle support, and changes in intrathoracic and intra-abdominal pressures may be the proposed mechanisms for the spinal deformities. Compensatory lumbar paraspinal over-activity due to the inability to generate normal intra-abdominal pressures because of a deficient abdominal wall musculature mechanism seems to be the plausible explanation for the thoracic hypokyphotic deformity observed. As a corollary, a failing abdominal wall musculature mechanism has been implicated in the risk for low back pain and its sequelae. Our case implicates that an intact abdominal musculature unit might be important in the maintenance of overall spinal function and stability. Maintaining normal intra-abdominal pressures, and the effects of abdominal exercises on this mechanism, i.e. training specificity, remain an important adjunct to our routine treatment of patients with low back pain.