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Comparative Study
. 2020 Jul 6;21(1):437.
doi: 10.1186/s12891-020-03466-0.

Clinical efficacy and radiographic K-rod stabilization for the treatment of multilevel degenerative lumbar spinal stenosis

Chaohua Fu  1   2 , Tianjun Chen  1 , Yuhao Yang  1 , Hua Yang  1 , Maohui Diao  3 , Guowei Zhang  1 , Zhisheng Ji  4 , Hongsheng Lin  5
Affiliations
Comparative Study

Clinical efficacy and radiographic K-rod stabilization for the treatment of multilevel degenerative lumbar spinal stenosis

Chaohua Fu et al. BMC Musculoskelet Disord. .

Abstract

Background: This study compares the use of radiographic K-Rod dynamic stabilization to the rigid system for the treatment of multisegmental degenerative lumbar spinal stenosis (MDLSS).

Methods: A total of 40 patients with MDLSS who underwent surgical treatment using the K-Rod (n = 25) and rigid systems (n = 15) from March 2013 to March 2017 were assessed. The mean follow-up period was 29.1 months. JOA, ODI, VAS and modified Macnab were assessed. Radiographic evaluations included lumbar lordosis angle, ISR value, operative and proximal adjacent ROM. Changes in intervertebral disc signal were classified according to Pfirrmann grade and UCLA system.

Results: JOA, ODI and VAS changed significantly after the operation to comparable levels between the groups. However, the lumbar lordosis significantly decreased at final follow-up between both groups. The ROM of the proximal adjacent segment increased at final follow-up, but the number of fixed segment ROMs in the K-Rod group were significantly lower at the final follow-up than observed prior to the operation. In both groups, the ISR of the proximal adjacent segment decreased, most notably in the rigid group. The ISR of the non-fusion fixed segments in the K-Rod group increased post-operation and during final follow-up. The levels of adjacent segment degeneration were higher in the rigid group vs. the K-Rod group according to modified Pfirrmann grading and the UCLA system.

Conclusions: Compared with the rigid system for treatment of MDLSS, dynamic K-Rod stabilization achieves improved radiographic outcomes and improves the mobility of the stabilized segments, minimizing the influence on the proximal adjacent segment.

Keywords: Dynamic stabilization system; K-rod; Multisegmental degenerative lumbar spinal stenosis; Selective fusion.

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Conflict of interest statement

The authors declare that they have no competing interests.

Figures

Fig. 1
Fig. 1
Effects of dynamic vs rigid K-Rod stabilization on the lumbar lordosis angle and motion during DLSS treatment. a Lumbar lordosis angle between K-Rod and rigid groups; b the total lumbar ROM of the two groups at the last follow-up; c & d ROM of the lower and upper adjacent segments at final follow-up; e ROMs of non-fusion fixed segments pre-operatively and post-operatively
Fig. 2
Fig. 2
Comparison of dynamic and rigid K-Rod stabilization on lumbar ISR and intervertebral disc degeneration in the treatment of MDLSS. a The ISR value of upper adjacent segment in K-Rod and rigid groups at different point in time including pre-operative, post-operative and last follow up; b the ISR value of lower adjacent segment in the K-Rod and rigid groups at different points in time including pre-operative, post-operative, and last follow-up; (b) ROM of lower and upper segments at final follow-up; c ISR value of non-fusion fixed segment at pre-operative, post-operative, and last follow-up
Fig. 3
Fig. 3
Comparison of pre-operative and post-operative imaging: a-d: K-rod; e-g rigid (DR: a, c, e and g; MRI: b, d, f & h); a, b, e and f: pre-operative images; c, d, g & h: post-operative images of patients
See this image and copyright information in PMC

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