Muscle-Sparing Wiltse Transforaminal Lumbar Interbody Fusion: A Technical Guide for the Modified Paraspinal Approach

The Wiltse transforaminal lumbar interbody fusion (W-TLIF) modifies the traditional open posterior lumbar fusion to treat the same degenerative pathologies through a smaller, muscle-sparing incision that accesses the lumbar spine through the paramedian corridor between the multifidus and longissimus muscles, preserving the posterior musculature and limiting iatrogenic soft tissue trauma. This protocol provides a reproducible, step-by-step guide to performing the muscle-sparing W-TLIF for lumbar decompression and interbody fusion. After prone positioning and fluoroscopic level localization, a paramedian incision is made, and the lumbodorsal fascia is divided to develop the natural interval between the multifidus and longissimus, and sequential tubular dilation is used to dock a tubular retractor on the facet complex. An ipsilateral hemilaminectomy and medial facetectomy are performed to decompress the neural elements, followed by discectomy and endplate preparation. An interbody cage packed with autograft and allograft is placed, and the construct is completed with percutaneous pedicle screws under fluoroscopic guidance. The technique yields low intraoperative blood loss and short hospital stays, with same-day discharge feasible in selected patients and improvement in patient-reported outcomes. The muscle-sparing W-TLIF is a safe, reproducible, and teachable evolution of the traditional posterior lumbar fusion that emphasizes anatomical preservation and improved recovery.