Direct Repair of Lumbar Pars Interarticularis Defects by Utilizing Intraoperative O-Arm-Based Navigation and Microendoscopic Techniques.

STUDY DESIGN: A retrospective analysis of the clinical outcomes of eight patients with the lumbar pars interarticulars defects treated by direct repair with the aid of intraoperative O-arm based navigation and microendoscopic techniques.

OBJECTIVE: The aim of this study was to investigate the efficacy and safety of direct screw repair by using minimally invasive surgery for the lumbar pars interarticulars defects in a pilot study.

SUMMARY OF BACKGROUND DATA: Direct repair of pars interarticulars defects has been used to treat young adult patients. Reports concerning direct repair by minimally invasive techniques for pars interarticulars defects are quite rare.

METHODS: Review of medical records identified eight consecutive patients treated with intraoperative O-arm based navigation and microendoscopic techniques. Debridement and autograft of pars interarticularis defects was performed under microendoscopic procedure. Then, percutaneous bilateral intralaminar screws were inserted by utilizing intraoperative navigation. The clinical and radiological data were collected and analyzed retrospectively.

RESULTS: Eight patients had a mean age of 28.4 years, and five were 30 years or younger at the time of treatment. Symptoms included axial back pain in 100% of patients without concomitant radiculopathy. Autograft was used in all cases. The average follow-up duration was 27.4 months with a range of 20 to 33 months. Symptoms resolved completely or partially in all patients. Low back pain visual analog scores decrease from preoperative 6.8 to postoperative 1.4 of eight cases. Of 16 pars defects, healing was observed in 13 (81.3%) at last radiological follow-up. One patient with bilateral fusion failure refused revision surgery because of mild complaint. No complications such as dural tear, nerve root injury, and infection occurred.

CONCLUSION: Minimally invasive direct repair of the pars interarticularis defects with intralaminar screws by using microendoscopic system and navigation procedure can provide safe and effective treatment of spondylolysis with satisfactory clinical and radiological outcomes, which need some special tools with steep learning curve.

LEVEL OF EVIDENCE: 4.