Chapter Clinical Summary
Academic synthesis, diagnostic methodology, and surgical recommendationsPosterior lumbar interbody fusion represents one of the foundational pillars of reconstructive spine surgery for degenerative instability, spondylolisthesis, recurrent disc herniation, and adult spinal deformity. Developed originally as Posterior Lumbar Interbody Fusion (PLIF) requiring bilateral laminotomies and medial thecal sac retraction, the technique was subsequently refined into Transforaminal Lumbar Interbody Fusion (TLIF). By accessing the intervertebral disc through a unilateral transforaminal corridor via complete facetectomy, TLIF significantly reduces neural retraction of the thecal sac and cauda equina. The advent of tubular retractors, computer navigation, and expandable cages led to Minimally Invasive TLIF (MIS-TLIF), minimizing muscle trauma and blood loss. However, successful arthrodesis and lordosis restoration depend on thorough disc space clearing, meticulous cartilaginous endplate preparation without structural violation, optimal interbody cage positioning, and robust posterior pedicle screw fixation.
Present the anatomical, biomechanical, and technical foundations of PLIF, open TLIF, and MIS-TLIF. The reader will learn to evaluate indications and contraindications, plan trajectory and implant sizing, execute thorough endplate preparation, achieve segmental lordosis, and prevent complications such as cage subsidence, thecal sac tear, radicular injury, and pseudarthrosis.
Interbody arthrodesis places structural graft within the anterior column, which carries 80% of axial load. This maximizes fusion surface area under compression (Wolff's Law), restores disc height, and indirectly decompresses neural foramina. TLIF evolved from PLIF to reduce dural retraction and cauda equina trauma by utilizing a unilateral foraminal window created by facetectomy.
Indications include degenerative and isthmic spondylolisthesis, symptomatic discogenic low back pain with instability, recurrent disc herniations, degenerative lumbar scoliosis, and failed prior decompression. Preoperative planning utilizes standing spinopelvic radiographs to determine pelvic incidence (PI) and target segmental lordosis, CT to evaluate facet anatomy and endplate sclerosis, and MRI to identify neural compression.
Open TLIF provides wide visualization and allows concomitant posterior column shortening osteotomies for deformity correction. MIS-TLIF utilizes expandable tubular retractors or percutaneous ports, sparing multifidus muscle detachment, reducing postoperative pain, intraoperative blood loss, and length of hospital stay while achieving comparable fusion rates.
Complete discectomy and thorough curettage of the cartilaginous endplate are vital for fusion. Preserving the structural cortical bone of the bony endplate is critical to avoid cage subsidence. Cages (PEEK, titanium, 3D-printed porous titanium) are packed with autograft/allograft and positioned anteriorly to maximize segmental lordosis restoration.
Complications include incidental durotomy, exiting or traversing root injury, cage subsidence, cage migration, pseudarthrosis, and infection. Careful neural retraction, avoiding oversized trials, and meticulous posterior pedicle screw compression across the cage mitigate these risks.
When planning posterior interbody fusion, the surgeon must match the technique to the clinical objective. For high-grade central stenosis with isthmic spondylolisthesis or adult deformity requiring multi-level column realignment, open TLIF provides versatile access. For single-level degenerative spondylolisthesis or recurrent disc herniation with radiculopathy, MIS-TLIF provides rapid recovery with minimal muscle morbidity. Intraoperatively, the exiting nerve root must be visually protected in the superior foramen while the traversing root is gently retracted medially with a protected sleeve. During disc space preparation, straight and angled curettes remove cartilage down to bleeding subchondral bone without violating the cortical endplate. Placing the cage in the anterior third of the disc space and applying posterior compression across pedicle screws optimizes lordosis and locks the implant securely.