Spondylolisthesis
Spondylolisthesis is subluxation (slippage) of one vertebral body on another. Typically the subluxation is due to degenerative (arthritis) changes, but subluxation can also be due to trauma, spondylolysis (pars defect), or uncommonly tumor or infection. The degree of slippage is graded from 1-4. Symptoms include back (or neck) pain and radiculopathy. Treatment is typically a fusion procedure (TLIF, XLIF, or ALIF), but a micro-decompression can sometimes be performed for a patient with predominantly radiculopathy symptoms (arm or leg pain).
TLIF -Trans-Foraminal Interbody Fusion
PLIF -Posterior Lumbar Interbody Fusion
Trans-Foraminal Interbody Fusion (TLIF) or Posterior Lumbar Interbody Fusion (PLIF) are both posterior methods to do a lumbar fusion. Both procedures require a laminotomy (or laminectomy), diskectomy with subsequent insertion of an allograft (either cadaver or PEEK) and/or autograft (bone from the patient’s own body) into the disk space. Over time, the 2 lumbar segments fuse and become one segment. Instrumentation (usually titanium pedicle screws) is often inserted to help stabilize the segment while the fusion heals.
DLIF or XLIF (Lateral Interbody Fusion)
DLIF or XLIF (Lateral Interbody Fusion) is another way to do a lumbar fusion. Instead of inserting a PEEK allograft via a posterior approach (like in TLIF or PLIF), the allograft is implanted laterally (through the right or left side of the disk space). This procedure can only be performed at L4/5 or higher levels and requires dissection through the psoas muscle. After the diskectomy and placement of the DLIF or XLIF graft, instrumentation is then usually put in (either via a lateral titanium plate or posterior pedicle screws).
