Motion segment-sparing repair of symptomatic chronic pars defects

Area of Science:

• Orthopedic Surgery
• Spine Surgery
• Biomechanical Engineering

Background:

• Symptomatic chronic spondylolysis (SP) management typically involves spinal fusion or direct pars repair.
• Direct pars repair is preferred for younger patients due to its motion segment-sparing nature and lower biomechanical impact.
• The study investigates the expanded indications and limitations of direct pars repair for SP.

Purpose of the Study:

• To explore the limits of direct pars repair for symptomatic chronic spondylolysis.
• To identify predictors of symptom relief and radiographic fusion failure after direct pars repair.
• To evaluate the safety and efficacy of expanding direct pars repair indications.

Main Methods:

• Retrospective review of 49 patients undergoing direct pars repair for SP between 2002 and 2009.
• Analysis of clinical outcomes, including reoperation rates for symptom relief.
• Radiographic assessment for fusion failure and evaluation of disc degeneration (Modified Pfirrmann Scale).

Main Results:

• Only 7 out of 49 patients required reoperation, with 6 being female (p=0.049).
• Successful radiographic fusion and symptom relief were observed in patients with up to 30% slip percentage.
• Disc degeneration did not predict symptom persistence or fusion failure; high-grade disc disease patients experienced symptom relief.

Conclusions:

• Direct pars repair can be safely extended to patients with Grade I spondylolisthesis and high-grade disc disease.
• Female patients with bilateral L-5 SP and low lordotic angles may be better candidates for posterior spinal fusion (L-5 to S-1).
• No specific predictors of treatment failure were identified in this cohort.