Transfacet Pedicle Sparing, Posterior Spinal Fusion (PSF) and Transforaminal Lumbar Interbody Fusion (TLIF) in those with L1-L2 Disc Located in the Region of Spine Biomechanical and Neural Transition Zone; Case Series

Abstract

Background: Lumbar disc number 1 and 2 (L1 and L2) although anatomically located in lumbar region but it is specific location pose a caveat to surgeon to presage for conus medullaris and also for its great biomechanical standpoint in thoracolumbar region. In our experience with this group of patients we used transfacet pedicle sparing approach to care for conus and also we performed short segment fusion to augment this highly demanding biomechanical region.

Materials and Methods: From 2008 till now we operated 13 cases with L1-L2 disc underwent operations with this technique and after operation received Jewett hyperextension brace for 3 months. One patient because of central hard calcified disc received thoracoabdominal approach and from anterior got decompression. All surgery performed under high magnification of microscope and bone removal was done by powered drill.

Results: In About 6 case decompression was performed bilaterally to reach the central portion of the disc. In all patients pedicle screw was used for fixation, in 5 TLIF banana cage was also used and in 4 cases spinous process bone used as interbody graft. Only 2 cases presented with severe L2 radiculopathy and another 11 patients came with feature of cauda equine or conus problem. Axial back pain was crucial symptom in 8 cases. In 2 patients there is multiple discs with L2-L3 and one with T12-L1. There was no aggravation in neurological deficit and we have no problem with CSF leak or wound. Fusion achieved in all patients and axial back pain resolved successfully.

Conclusion: We suggest that L1-L2 although innately considered a lumbar disc should be regarded and considered as thoracic disc and the surgeon should not rely only on where the conus terminated in MRI. Small traction there can lead to catastrophic neurological damage. Therefore by using transfacet pedicle sparing under microscopic guide the cord should be decompressd by drill and not putting kerisson under already stenotic canal if neurological injury would be prevented.