The degree of Degenerative Disc Disease (DDD) affects post-operative lordosis after one or two levels Extreme Lateral Interbody Fusion (XLIF)? A retrospective review study.

Introduction: Degenerative Disc Disease (DDD) leads to significant spinal structural changes such as
degeneration of the facets and the intervertebral discs which reduce the lumbar lordosis
long term. The degree of these structural changes has not been studied extensively as
a regulatory factor of the final post-operative lordosis after Extreme Lateral Interbody
Fusion (XLIF). The authors aimed to review the role of DDD in the final lumbar lordosis
after surgery.

Methods: A retrospective review study was conducted from September 2015 to February 2017
including one to two levels XLIFs performed in our institution. All these cases were
treated for symptomatic degenerative disc disease with implants of the same
dimensions. The patients were stratified according to the degree of their DDD using the
Pfirrmann and Parthia classifications. The authors collected data on patients’
demographics, BMI, pre-operative lordosis, pre-operative segmental lordosis, type of
fixation, post-operative lordosis, and post-operative segmental lordosis.

Results: Eighty patients were finally included (Age:25-76 years old). Thirty-eight were males
(47.5%). Forty-two cases (52.5%) were one-level XLIF. There were no intra-operative or
post-operative complications. Blood loss was minimal (50-70 ml). Lumbar segmental
lordosis and disc height were significantly improved in all our cases (p=0.001). A
significant interaction was found between the degree of DDD and pre-operative lordosis
(p: .000 for Pfirrmann classification, p .001 for Parthia classification), as well as between
DDD and post-operative lordosis (p: .009 for Pfirrmann classification, p .000 for Parthia
classification). An analogous result was not observed in the study of segmental lordosis.

Conclusion : The degree of lumbar DDD defined by Pfirrmann and Parthia classifications is an
important factor for the calculation of the desirable correction of lumbar lordosis after
XLIFs.