Surgical treatment of dysplastic and isthmic spondylolisthesis

Background. Dysplastic spondylolisthesis results from a congenital malformation of the vertebral processes, sometimes accompanied by spina bifida; its progression causes subluxation or dislocation in the intervertebral joints and an anterior repositioning of the entire vertebra. Isthmic spondylolisthesis, on the other hand, most often results from a spinal fissure. The body and part of the arch are dislocated, while the intervertebral joints are normal. Treatment is indicated when there is pain, neurological symptoms, or radiological signs of progression of the slippage. Material and methods. Twenty-five patients with spondylolisthesis (14 with dysplastic and 11 with isthmic) were treated surgically using in situ fusion, the Harrington method with posterolateral fusion, or transpedicular instrumentation with posterolateral fusion. Grade III or IV spondylolisthesis was reduced with traction screws. Decompression of the spinal canal and intervertebral foramina was performed in patients with neurological deficits. Results. Complete pain relief was achieved in 72% of the patients, partial in 24%, none in 4%. Neurological deficits subsided in the majority of patients. Complete recovery was achieved in 87.5% of the transpedicular patients, 72.7% of the in situ fusion patients, and 50% of the Harrington patients. Transient neurological complications occurred in 2 patients after complete reduction of the displacement, mechanical complications (hook dislocation, rod or screw failure) in 2 patients. Conclusions. Complete reduction of the slippage proved to be a riskier procedure than partial reduction.