Lumbar spondylolysis - Current concepts review

Lumbar pars interarticularis (PI) injury or spondylolysis occurs only in humans. This represents a stress fracture of the PI. Excessive loading in repetitive hyperextension is a significant risk factor and occurs most commonly at L5 followed by L4. It is bilateral in 80% of symptomatic cases but can be unilateral defect as well which runs a more benign course. Symptoms of low back pain relating to this lesion are more common in young athletes involved in trunk twisting sports. Like other stress fractures, the pain may come on abruptly or more insidiously over time and only related to certain activities. The pathologic progression starts with a stress reaction in the pars, progressing to an incomplete stress fracture, and then a complete pars fracture. Diagnosis is dependent on clinical examination and radiological imaging studies (plain radiography, computed tomography (CT) scans and magnetic resonance imaging (MRI) scans). Treatment is dependent on symptoms as well as radiographic stage of the lesion. Conservative management is the mainstay of treating early lesions. A comprehensive rehabilitation program incorporates core spinal stabilization exercises. Athletes should not return to sports until pain free. Professional sporting individuals are at increased risk of failure of resolution of symptoms that may require early surgical repair of the PI defect. Modified Buck's technique & pedicle screw-hook constructs for direct repair has a high success rate in patients who have persistent low back pain. Minimally invasive lumbar pars defect repair has given similar successful outcome with added advantage of minimizing muscle injury, preserving the adjacent joint and reduced hospital stay. Functional outcome is evaluated using the Visual Analogue Scale (VAS) for back pain, Oswestry Disability Index (ODI) and 36-Item Short-Form Health Survey (SF-36). Preoperative ODI and SF-36 physical component scores (PCS) are significant predictor of a good functional outcome.