Experimental substantiation of technical variants of pedicle-lengthening osteotomy for decompression of the dural sac and nerve roots in the lumbar spine

Objective. To determine experimentally the mechanical conditions required for decompression of the dural sac and spinal nerve roots during pedicle-lengthening osteotomy (PLO) with elongation of pedicles at the lumbar level.

Material and Methods. The experiments were conducted on three cadaver specimens of L1–L5 vertebral motor segments obtained at the forensic section from individuals aged 45–60 within two days after death in compliance with the standards for preparing human tissue for biomechanical studies. The contents of the vertebral and root canals were removed from the specimens of the lumbar spine, leaving all elements of the osteoligamentary support complex intact. Three experiments were conducted on each specimen. In the first experiment, bilateral pedicle lengthening osteotomy imitating PLO was performed on the L4 vertebra of the anatomical specimen. In the second experiment, osteotomies of the inferior articular processes of L3 at the level of their base were performed on the same specimen in order to mobilize the posterior support complex. In the third experiment, bilateral pedicle osteotomy was additionally performed on the L3 vertebra. The described experiments were repeated three times on three anatomical specimens. The obtained data were recorded in protocols, and then statistical processing was performed using descriptive statistics methods. The sets of study results measured on a quantitative scale for normality were checked using the Kolmogorov–Smirnov Z-criterion. To prove the statistical significance (or lack thereof) of the values of the compared parameters, the Mann–Whitney U-test was used. Results were considered significant if the level of statistical significance p was less than or equal to 0.05.

Results. The increase in the sagittal spinal canal size after PLO due to the elongation of the L4 pedicles by 4 mm is achieved with a traction force of 97 N, by 5 mm – with 162 N, by 6 mm – with 240 N, and by 7 mm – with 306 N. Mobilizing osteotomy of the inferior articular processes of the L3 reduces the traction forces necessary for decompression to 30 N, 73 N, 125.5 N, and 182 N, respectively, which is 1.7–3.2  times less than the PLO values without mobilization. Additional bilateral pedicle osteotomy on the overlying L3 vertebra does not provide further decrease in the traction forces necessary to increase the sagittal size of the spinal canal.

Conclusion. The technique of decompression of the dural sac and nerve roots in the lumbar spine by means of pedicle-lengthening osteotomy with elongation of pedicles is a promising option for surgical treatment of lumbar spinal stenosis. The data obtained in this study may be of interest, especially with the possible development of another technical solution and instrumentation for implementing PLO.

1. Katz JN, Zimmerman ZE, Mass H, Makhni MC. Diagnosis and management of lumbar spinal stenosis: a review. JAMA. 2022;327:1688–1699.

2. DOI: 10.1001/jama.2022.5921

3. Ravindra VM, Senglaub SS, Rattani A, Dewan MC, Härtl R, Bisson E, Park KB, Shrime MG. Degenerative lumbar spine disease: estimating global incidence and worldwide volume. Global Spine J. 2018;8:784–794. DOI: 10.1177/2192568218770769

4. Khalepa RV, Amelina EV, Kubetsky YuE. Endoscopic and microsurgical decompression for central lumbar spinal stenosis. Russian Journal of Spine Surgery (Khirurgiya Pozvonochnika) 2024;21(3):59–68. DOI: 10.14531/ss2024.3.59-68

5. Abakirov MD, Nurmukhametov RM, Mamyrbaev ST, Al-Bavarid OA. Results of revision surgery for degenerative dystrophic diseases of the lumbosacral spine. Polytrauma. 2020;(1):31–40. DOI: 10.24411/1819-1495-2020-10005

6. Nakajima Y, Nagai S, Michikawa T, Hachiya K, Ito K, Takeda H, Kawabata S, Yoshioka A, Ikeda D, Kaneko S, Hachiya Y, Fujita N. Predictors of patient dissatisfaction after lumbar spinal canal stenosis surgery: a multicenter retrospective study. Spine Surg Relat Res. 2024;8:322–329. DOI: 10.22603/ssrr.2023-0256

7. Aganesov AG, Aleksanyan MM, Gemdzhian EG. Spinal canal stenosis: comparative analysis of minimally invasive bilateral decompression through a unilateral approach and laminectomy. Russian Journal of Spine Surgery (Khirurgiya Pozvonochnika). 2024;21(1):35–43. DOI: 10.14531/ss2024.1.35-43

8. Mlyavykh SG, Bokov AE, Yashin KS, Karyakin NN, Anderson DG. Pedicle-lengthening osteotomy for the treatment of lumbar spinal stenosis: pre-clinical study of novel orthopedic devices. Modern Technologies in Medicine. 2018;10(2):37–46. DOI: 10.17691/stm2018.10.2.04

9. Gao M, Zou J, Zhang Z, Luo Z, Yang H. Evaluation of the influence of pedicle-lengthening osteotomy on lumbar stability. Am J Transl Res. 2016;8:2070–2078.

10. Sikilinda VD, Akopov VI, Khloponin PA, et al. Preparation of experimental animal and human tissues for biomechanical and morphological studies. Methodical recommendations. Rostov-on-Don – St. Petersburg, 2002.

11. Kolesov SV, Gavryushenko NS, Kudryakov SA, Shavyrin IA. Experimental study of anterior correction and fixation techniques for spinal deformities Russian Journal of Spine Surgery (Khirurgiya Pozvonochnika). 2011;(3):82–88.

12. Friis EA, Amold PM, Goel VK. 9 – Mechanical testing of cervical, thoracolumbar, and lumbar spine implants. In: Mechanical Testing of Orthopaedic Implants. 2017. P. 161–180. DOI: 10.1016/b978-0-08-100286-5.00009-3

13. Wang C, Xu F, Jia L, Liu Y, Zhang S. Lumbar fusion efficacy with local bone grafting and platelet-rich plasma: a clinical investigation in treating degenerative lumbar spinal stenosis in the elderly. Int Orthop. 2024;48:2963–2970.

14. DOI: 10.1007/s00264-024-06294-2

15. Li W, Wei H, Zhang R. Different lumbar fusion techniques for lumbar spinal stenosis: a Bayesian network meta-analysis. BMC Surg. 2023;23:345.

16. DOI: 10.1186/s12893-023-02242-w

17. Mlyavykh SG, Bokov AE, Aleynik AYa, Yashin KS, Karyakin NN. Open and minimally invasive technologies in surgical treatment of stable symptomatic stenosis of the lumbar spine. Modern Technologies in Medicine. 2019;11(4):135–145.

18. DOI: 10.17691/stm2019.11.4.16

19. Mlyavykh SG, Bokov AE, Yashin KS, Anderson DG. Pedicle-lengthening osteotomy for the treatment of lumbar spinal stenosis: the surgical technique (pilot clinical study). Modern Technologies in Medicine. 2018;10(3):58–69.

20. DOI: 10.17691/stm2018.10.3.7

21. Kiapour A, Anderson DG, Spenciner DB, Ferrara L, Goel VK. Kinematic effects of a pedicle-lengthening osteotomy for the treatment of lumbar spinal stenosis. J Neurosurg Spine. 2012;17:314–320. DOI: 10.3171/2012.6.SPINE11518

22. Mlyavykh S, Ludwig SC, Kepler CK, Anderson DG. Five-year results of a clinical pilot study utilizing a pedicle-lengthening osteotomy for the treatment of lumbar spinal stenosis. J Neurosurg Spine. 2018;29:241–249. DOI: 10.3171/2017.11.SPINE16664

23. Nadulich KA, Shapovalov VM, Teremshonok AV, Vasilevich SV. Experimental evaluation of correction features of posttraumatic kyphosis of thoracic and lumbar spine. Traumatology and Orthopedics of Russia. 2010;16(2):86–88. DOI: 10.21823/2311-2905-2010-0-2-86-88