Management of Isthmic Spondylolisthesis in Adults
Historically pain medications, anti-inflammatory drugs, and physiotherapy were prescribed for symptomatic spondylolisthesis in adult patients. However, a recent clinical study (a prospective randomized trial) pointed out that such a therapeutic approach was ineffective in controlling pain and incapacitation. Further, this study indicated that surgery only brought symptomatic relief in the majority of patients.
Three main types of surgical approaches may be applicable. Common to all three approaches is the use of internal fixation (screws, rods or plates) and the apposition of local bone graft to enhance a solid bony fusion. The bone graft can be obtained from local bone such as the resected lamina and spinous process and sometimes from the iliac bone (pelvis).
The three surgical procedures are as follows:
1. Posterior decompression with pedicle screw fixation and posterolateral fusion. This operative plan is reserved for patients with mild to moderate slips with marked disc space narrowing (Fig. 8).
Figure 8. Left: Preoperative lateral x-ray illustrating isthmic spondylolisthesis.
Middle/Right: Post-operative lateral and posterior x-rays showing the
pedicle screw fixation (instrumentation) to stabilize the lumbar spine.
2. Posterior decompression and pedicle screw fixation with the addition of lumbar interbody fusion (PLIF or TLIF). This operative strategy is reserved for slips with a relatively preserved disc space and in cases where slip reduction is performed (Fig. 9, 10).
Figure 9. Left: Pre-operative x-ray indicating spondylolisthesis.
Right: Post-operative x-ray, cage and pedicle screw fixation.
Figure 10. Left/Middle: Lateral x-ray and MRI indicating grade 4 spondylolisthesis.
Right: Post-operative x-ray showing implant and screw fixation following complete slip reduction.
3. Decompression and fixation with sacral transdiscal screw fixation ending in the L5 body. This operative plan is performed in patients with advanced slip accompanied by advanced disc space narrowing.
Management after Surgery
The use of modern spinal instrumentation eliminates the need for post-operative bracing. Soon after surgery, the patient can get on his feet and walk, as tolerated. Performance of isometric exercises to strengthen the abdominal and paraspinal muscles is recommended. It takes about 3-6 months for a solid bony fusion to mature. Swimming and other non-strenuous sports activities can be performed usually 3-6 months after surgery. Serial post-operative x rays will determine the progress toward a solid bony fusion.
While the outcome of surgery in patients with degenerative disc disease may sometimes be unpredictable and relies among other factors on socioeconomic cofounders, the outcome of surgery in adult isthmic spondylolisthesis is much more predictable and favorable. The combination of mechanical instability and local spinal stenosis make this kind of surgery rewarding.