Transforaminal lumbar interbody fusion (TLIF) and instruments. Prospective study with the minimum of 20-month follow-up

Objective: The objective of the study was prospective evaluation of the potential of TLIF for the therapy of istmical and degenerative low-grade degenerative spondylolisthesis (grade one according to Meyerding) of lumbosacral (LS) spine, Methods: Based on informed approval, LS stabilisation using the TLIF technique was performed in 38 patients of which 34 (95%) met the study specifications. The interval between the surgery and the last check at an outpatient unit ranged between 20 and 36 months (24 months on an average). Twenty one patients (the first group) had a unilateral surgery without laminectomy, 13 patients (the second group) had a channel decompression surgery using laminectomy or partial laminectomy followed by unilateral TLIF. Only one interbody cage was always implanted, the cage being filled by autologous bone obtained in the access site. The subject of evaluation was the objective neurological picture, the pre-surgery and post-surgery Oswestry Disability Index (ODI), as well as total intensity of pain expressed by the visual analogue score (VAS), and the total post-op satisfaction of the patients. After two years, a CT exam was performed to assess the intervertebral connection and the position of the screws. Results: Cases of statistically significant decrease in the mean values of scales pre and post-surgery were detected. The mean value for ODI decreased from 52.8 to 23.2 (p < 0.01) and from 47.2 to 25.5 (p < 0.01) in the first and in the second group, respectively. Similarly, there was a decrease in the VAS scale respectively from 7.7 to 3.6 (p < 0.01) and from 7.4 to 3.8 in the first and in the second group post-op (p < 0.01). At the same time, no statistically significant difference between the results for the individual groups was found (p > 0.05). On the whole, 132 transpedicular screws were implanted - the rate of extrapedicular screws was 5 % and 7 % for the first and second group, respectively. No statistically significant difference was found between the two groups in terms of screw introduction (p > 0.01). Good bone fusion was achieved in the first group in all the cases, while pseudoarthrosis was detected in one fused segment in the second group. Conclusion: The first group had slightly better clinical results, however, without this making a statistically significant difference. TLIF is a safe technique of stabilisation of LS spine, the risk of extrapedicular placement of the screw is not associated with the scope of the channel revision. One interbody cage filled with autologous bone from the access site is sufficient for obtaining quality interbody fusion. The clinical result does not correlate with the quality of bone fusion.