Does Osteoporosis Contribute to Clinical and Radiographical Outcomes of Transforaminal Lumbar Interbody Fusion for Postmenopausal Women with Lumbar Spinal Disorders?

Methods: Thirty-seven postmenopausal women who underwent one-level (L4-5) unilateral TLIF using two open box carbon cages (OCCs) were reviewed for a minimum 2-year follow-up. The patients were divided into following two groups according to BMD, which was measured by DEXA in the lumbar spine (L2-3): Osteoporotic group (Group-O: 18 patients, a mean age and BMD: 66.6 years, 0.686g/cm2); and non-osteoporotic group (Group-NO: 19 patients, 71.3 years, 0.946g/cm2). Radiographical assessment included percent of slippage (%slip), percent of anterior and posterior disc height (%ADH, %PDH), disc angle (DA), and fusion status. Clinical outcomes were evaluated by means of the scoring system of the Japanese Orthopedic Association (JOA score) for low back pain. Changes in these radiographic parameters and recovery rate of the JOA scores were compared between the two groups during follow-up period. Mann-Whitney U-test was used for statistical analysis.

Results: At the final follow-up, a mean correction loss of %slip, %ADH and DA in Group-O (2.1%, 20.5%, 2.4 degrees) was significantly greater than that in Group-NO (0.1%, 8.1%, and 0.5 degrees) (p<0 .05). Whereas, although the average correction loss of %PDH in Group-O (17.2%) was greater than that Group-NO (7.0%), there no significant difference. Radiographic fusion successfully obtained both groups (94.7% and 88.9% Group-NO). There difference recovery rate JOA score between (73.4%) (72.3%).

Conclusion: Osteoporosis significantly contributed to postoperative correction loss of the reconstructed spine by TLIF using OCCs in postmenopausal women. However, in one-level TLIF, osteoporosis did not exert the adverse effect on radiographic fusion and clinical outcomes.