Uniportal Endoscopic-Assisted Direct Pars Repair Using the Smiley Face Rod Method for Lumbar Spondylolysis

Lumbar spondylolysis is a common cause of low back pain among young athletes. Although direct pars repair using the Smiley Face Rod method provides stable fixation, conventional approaches require muscle dissection, which may delay postoperative recovery. This report describes a novel ultraminimally invasive technique that combines uniportal endoscopic assistance with this robust fixation system. A 20-year-old male gymnast presented with bilateral L5 terminal-stage spondylolysis that was refractory to 6 months of conservative treatment. Uniportal endoscopic-assisted direct pars repair was performed. Through a single 8-mm portal, the pars defects were meticulously debrided and decorticated under direct endoscopic visualization. Autologous iliac crest bone graft was then delivered into the defects through the endoscope’s sheath. Subsequently, percutaneous pedicle screws were inserted through bilateral 2- to 3-cm incisions and connected with a subcutaneously tunneled U-shaped rod to achieve compression across the defects. The patient’s low back pain resolved immediately after surgery. Computed tomography confirmed bony union at 3 months, at which point the patient returned to competitive gymnastics. This uniportal endoscopic-assisted technique for the Smiley Face Rod method is technically feasible and may represent a promising approach that minimizes iatrogenic soft tissue injury. This ultra-minimally invasive strategy may offer advantages for elite athletes by facilitating rapid pain relief and enabling an early return to sport.