PLIF - posterior Lumbar Interbody Fusion

It is interbody (anterior) fusion done through posterior approach

Why PLIF-:-

• PLIF affords anterior stability without the less familiar / often morbid anterior approach
• Restores lumbar lordosis- PLIF reconstitutes the normal anatomic relationship between the motion segments and the neural structures.

Advantages of PLIF:-

• Load sharing support to posterior instrumentation
• Possibility of 'jacking' open the root canal / restoring disc height
• 360 degrees fusion through single posterior approach
• Restores sagittal alignment

INDICATION:-

Spondylolisthesis (isthmus, degenerative, or postlaminectomy spondylolisthesis)(

• Degenerative disc disease, Slip Disc , Herniated Disc , Prolapse Intervertebral Disc (PID) Complex Spinal Stenosis
• Mechanical instability due to Spinal Trauma/ Spinal Tumor / Spinal Metastasis
• Unstable spine due to spinal infection eg Tuberculosis
• Unstable spine due to Spinal Deformity- Scoliosis or Kyphosis .
• Salvage procedures – post op discitis etc

Contraindication:-

• Multilevel Disc disease
• Radicular pain only (no mechanical back pain)
• Severe osteoporosis

Relative contraindications

• Multiple posterior surgeries
• Smokers
• Significant co-morbid illnesses

PLIF technique-steps:-

• Exposure
• Decompression
• Discectomy
• Interbody bone grafting
• Fusion and Instrumentation

Exposure

• Harvest graft at the beginning
• Generous incision
• Expose tips of transverse processes
• Inter transverse exposure - lumbodorsal fascia, exiting (upper) root
• Facet joints / facet bleeder

Decompression

• Laminectomy
• Medial facetectomy
• Preserve pars Discectomy
• Root retraction up to midline
• Annular osteotomy may be required

End plate preparation

• Scrape off end plate cartilage, preserving the end plates
• Aggressive end plate debridement can lead to end plate fracture and loss of load bearing capacity
• Creation of mortises in the vertebral bodies helps 'lock' the graft – prevent dislodgement, resist translation
• If trough is too deep, it may lead to loss of axial load bearing properties

PLIF – inter body fusion

• Bone grafts
• Cortico cancellous chips
• ASIS strut
• Strut from spinous process
• Cages

Technical Difficulties in PLIF:-

• Excess root retraction - never retract root beyond midline !
• Dangerous above L3 – cannot retract conus !
• Poor interbody contact area in lysthesis > grade 2
• End plate removal
  • Too little = poor surface for graft to incorporate
  • Too much = possibility of graft sinkage