A 35-year-old woman has isthmic spondylolisthesis at L5-S1 with Meyerding grade II slip (26–50% displacement). She has failed 6 months of conservative treatment and has persistent radiculopathy. Which component of the surgical treatment is MOST critical to prevent progression and relieve neural compression?

• A In situ posterolateral fusion (PLF) alone without decompression
• B Full reduction of the slip to anatomical position followed by anterior interbody fusion
• C Removal of the defect in the pars interarticularis (direct repair) using hook-rod or screw construct
• D Decompression (laminectomy/foraminotomy) plus instrumented posterolateral fusion ✓

Explanation

For symptomatic isthmic spondylolisthesis grade II with persistent radiculopathy, the current standard is neural decompression (laminectomy or foraminotomy to decompress the L5 root in the L5-S1 foramina, often stenosed by fibrocartilaginous tissue at the pars defect) combined with instrumented posterolateral fusion to stabilise the segment and prevent further slip. Full anatomical reduction is controversial (high risk of L5 nerve root stretch injury) and is rarely performed; partial reduction is acceptable. Direct pars repair (Buck procedure) is reserved for young patients with grade I slip and no disc disease.

Reference: Maheshwari Essential Orthopaedics, 6th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.