Comparison of Posterior 2 Rod Instrumentation with 3 Rod Instrumentation in Corrective Spine Fusion Procedures and Risk for Mechanical Failure

Yusuf Altuntaş; İsmail Tüter; Necmi Cam; Mehmet Ali Talmaç; Haci Mustafa Özdemir

doi:10.18678/dtfd.1878895

Comparison of Posterior 2 Rod Instrumentation with 3 Rod Instrumentation in Corrective Spine Fusion Procedures and Risk for Mechanical Failure

Abstract

Aim: To compare clinical outcomes, radiographic parameters, and mechanical complications between 2-rod and 3-rod posterior instrumentation systems in patients undergoing long-segment fusion for degenerative spinal disorders.

Material and Methods: This retrospective study included 66 patients who underwent posterior-only corrective spinal fusion for degenerative spinal disorders. Clinical outcomes were assessed using the Visual Analog Scale (VAS) and Oswestry Disability Index (ODI). Radiographic parameters including Cobb angle, lumbar lordosis, pelvic incidence, pelvic tilt, and sacral slope were evaluated preoperatively, in the early postoperative period, at 1 year, and at final follow-up. Mechanical complications, including mechanical failure associated with pseudarthrosis requiring revision surgery and proximal junctional kyphosis, were recorded.

Results: A total of 66 patients were included, including 34 patients in the 2-rod group and 32 patients in the 3-rod group. Both groups demonstrated significant improvements in radiographic parameters and patient-reported outcomes during follow-up. Mechanical failure associated with pseudarthrosis requiring revision surgery occurred in four patients (11.7%) in the 2-rod group and in none of the patients in the 3-rod group. Proximal junctional kyphosis developed in 14.7% and 15.6% of patients, respectively. Repeated-measures analysis demonstrated significant improvements over time in VAS and ODI scores in both groups, without significant differences between groups.

Conclusion: Both 2-rod and 3-rod posterior instrumentation systems were associated with significant improvements in clinical and radiographic outcomes. Although mechanical failure was more frequently observed in the 2-rod group, no corresponding differences were observed in patient-reported outcomes. Given the retrospective, non-randomized design, these findings should be interpreted with caution and confirmed in larger prospective studies.

Keywords

Ethical Statement

This study was approved by the Clinical Research Ethics Committee of [Şişli Hamidiye Etfal Training and Research Hospital/Health Science University] (Approval No: 4317, February 27, 2024). All procedures performed in this study involving human participants were conducted in accordance with the ethical standards of the institutional and/or national research committee and with the principles of the Declaration of Helsinki.

References

Verma R, Lafage R, Scheer JK, Smith JS, Passias PG, Hostin R, et al. Improvement in back and leg pain and disability following adult spinal deformity surgery: study of 324 patients with 2-year follow-up and the impact of surgery on patient-reported outcomes. Spine (Phila Pa 1976). 2019;44(4):263-9. doi:10.1097/BRS.0000000000002815.
Ames CP, Smith JS, Scheer JK, Shaffrey CI, Lafage V, Deviren V, et al. A standardized nomenclature for cervical spine soft-tissue release and osteotomy for deformity correction: clinical article. J Neurosurg Spine. 2013;19(3):269-78. doi:10.3171/2013.5.SPINE121067.
Carreon LY, Glassman SD, Shaffrey CI, Fehlings MG, Dahl B, Ames CP, et al. Predictors of health-related quality-of-life after complex adult spinal deformity surgery: a Scoli-RISK-1 secondary analysis. Spine Deform. 2017;5(2):139-44. doi:10.1016/j.jspd.2016.11.001.
Schwab F, Ungar B, Blondel B, Buchowski J, Coe J, Deinlein D, et al. Scoliosis Research Society-Schwab adult spinal deformity classification: a validation study. Spine (Phila Pa 1976). 2012;37(12):1077-82. doi:10.1097/BRS.0b013e31823e15e2.
Yilgor C, Sogunmez N, Boissiere L, Yavuz Y, Obeid I, Kleinstück F, et al. Global alignment and proportion (GAP) score. J Bone Joint Surg Am. 2017;99(19):1661-72. doi:10.2106/JBJS.16.01594.
Kim HJ, Yang JH, Chang DG, Suk SI, Suh SW, Song KS, et al. Adult spinal deformity: current concepts and decision-making strategies for management. Asian Spine J. 2020;14(6):886-97. doi:10.31616/asj.2020.0568.
Dinizo M, Dolgalev I, Passias PG, Errico TJ, Raman T. Complications after adult spinal deformity surgeries: all are not created equal. Int J Spine Surg. 2021;15(1):137-43. doi:10.14444/8018.
Passias PG, Dave P, Smith JS, Lafage R, Onafowokan OO, Tretiakov P, et al. Cause and effect of revisions in adult spinal deformity surgery: a multicenter study on outcomes based on etiology. Spine J. 2025;25(6):1229-35. doi:10.1016/j.spinee.2024.12.023.

Marques MF, Fiere V, Obeid I, Charles YP, El-Youssef K, Lahoud A, et al. Pseudarthrosis in adult spine deformity surgery: risk factors and treatment options. Eur Spine J. 2021;30(11):3225-32. doi:10.1007/s00586-021-06861-w.
Bowden D, Michielli A, Merrill M, Will S. Systematic review and meta-analysis for the impact of rod materials and sizes in the surgical treatment of adult spine deformity. Spine Deform. 2022;10(6):1265-78. doi:10.1007/s43390-022-00556-y.
Lamas V, Charles YP, Tuzin N, Steib JP. Comparison of degenerative lumbar scoliosis correction and risk for mechanical failure using posterior 2-rod instrumentation versus 4-rod instrumentation and interbody fusion. Eur Spine J. 2021;30(7):1965-77. doi:10.1007/s00586-021-06870-9.
Williams JL, Sarraj M, Mechas CA, Pennington Z, Pumford AD, Postal Z, et al. The impact of screw density on mechanical complications in lumbar spine deformity constructs. Spine (Phila Pa 1976). 2025. doi:10.1097/BRS.0000000000005560. Epub ahead of print.
Zhao J, Li B, Chen Z, Yang C, Li M. Rod fracture after long construct fusion in adult spinal deformity surgery: a retrospective case-control study. J Orthop Sci. 2019;24(4):607-11. doi:10.1016/j.jos.2018.12.010.
Moniz-Garcia D, Stoloff D, Akinduro O, De Biase G, Sousa-Pinto B, Beeler C, et al. Two- versus multi-rod constructs for adult spinal deformity: a systematic review and random-effects and Bayesian meta-analysis. J Clin Neurosci. 2023;107:9-15. doi:10.1016/j.jocn.2022.11.011.
Buell TJ, Sardi JP, Yen CP, Okonkwo DO, Hamilton DK, Gum JL, et al. Use of supplemental rod constructs in adult spinal deformity surgery. Semin Spine Surg. 2023;35(4):101062. doi:10.1016/j.semss.2023.101062.
Ramey WL, Jack AS, Chapman JR. The lexicon of multirod constructs in adult spinal deformity: a concise description of when, why, and how. J Neurosurg Spine. 2022;36(6):1023-9. doi:10.3171/2021.10.SPINE21745.
Tsutsui S, Yamamoto E, Kozaki T, Murata A, Yamada H. Biomechanical study of rod stress in lumbopelvic fixation with lateral interbody fusion: an in vitro experimental study using synthetic bone models. J Neurosurg Spine. 2022;37(1):73-9. doi:10.3171/2021.11.SPINE21807.
Bourghli A, Boissière L, Kieser D, Larrieu D, Pizones J, Alanay A, et al. Multiple-rod constructs do not reduce pseudarthrosis and rod fracture after pedicle subtraction osteotomy for adult spinal deformity correction but improve quality of life. Neurospine. 2021;18(4):816-23. doi:10.14245/ns.2142596.298.
Park SJ, Kim HJ, Park JS, Kang DH, Lee CS. Sagittal alignment goals in adult spinal deformity surgery: a narrative review focusing on proximal junctional complications and clinical outcomes. Asian Spine J. 2026. doi:10.31616/asj.2025.0661. Epub ahead of print.
Lechtholz-Zey EA, Gettleman BS, Ayad M, Mills ES, Shelby H, Ton A, et al. The effect of osteoporosis on complications and reoperation rates after surgical management of adult thoracolumbar spinal deformity: a systematic review and meta-analysis. Global Spine J. 2024;14(8):2420-39. doi:10.1177/21925682241250031.
Kuo CC, Soliman MAR, Aguirre AO, Ruggiero N, Kruk M, Khan A, et al. Vertebral bone quality score independently predicts proximal junctional kyphosis and/or failure after adult spinal deformity surgery. Neurosurgery. 2023;92(5):945-54. doi:10.1227/neu.0000000000002291.
Khalid SI, Nunna RS, Maasarani S, Belmont E, Deme P, Chilakapati S, et al. Association of osteopenia and osteoporosis with higher rates of pseudarthrosis and revision surgery in adult patients undergoing single-level lumbar fusion. Neurosurg Focus. 2020;49(2):E6. doi:10.3171/2020.5.FOCUS20289.
Park SJ, Park JS, Lee CS, Kang DH. Risk factors for rod fracture at ≥L4-5 levels following long-segment fusion for adult spinal deformity: results from segment-based analysis. J Clin Med. 2025;14(16):5643. doi:10.3390/jcm14165643.
Sebaaly A, Riouallon G, Obeid I, Grobost P, Rizkallah M, Laouissat F, et al. Proximal junctional kyphosis in adult scoliosis: comparison of four radiological predictor models. Eur Spine J. 2018;27(3):613-21. doi:10.1007/s00586-017-5172-x.
Kyrölä K, Kautiainen H, Pekkanen L, Mäkelä P, Kiviranta I, Häkkinen A. Long-term clinical and radiographic outcomes and patient satisfaction after adult spinal deformity correction. Scand J Surg. 2019;108(4):343-51. doi:10.1177/1457496918812201.
Hassan Sayed Rashid MES, Abel Aziz Zaki MR, Fawzi Fouda AH, Ezzat Abdel Fatah AM. Management of adjacent segment disease after lumbar spine fusion for treatment of degenerative lumbar pathology. Zagazig University Medical Journal. 2026;32(3):1058-72. doi:10.21608/zumj.2026.462599.4436.
Sebaaly A, Gehrchen M, Silvestre C, Kharrat K, Bari TJ, Kreichati G, et al. Mechanical complications in adult spinal deformity and the effect of restoring the spinal shapes according to the Roussouly classification: a multicentric study. Eur Spine J. 2020;29(4):904-13. doi:10.1007/s00586-019-06253-1.

Details

Primary Language

English

Subjects

Orthopaedics

Journal Section

Research Article

Authors

Yusuf Altuntaş ^*
0000-0001-8561-7736
Türkiye

İsmail Tüter
0000-0002-8766-981X
Türkiye

Necmi Cam
0000-0001-7101-3106
Türkiye

Mehmet Ali Talmaç
0000-0001-7734-6438
Türkiye

Haci Mustafa Özdemir
0000-0001-6189-3605
Türkiye

Publication Date

August 21, 2026

Submission Date

February 1, 2026

Acceptance Date

July 22, 2026

Published in Issue

Year 2026 Volume: 28 Number: 2

DOI

https://doi.org/10.18678/dtfd.1878895

IZ

https://izlik.org/JA36CX28LB

Cite

RIS / Bibtex

APA

Altuntaş, Y., Tüter, İ., Cam, N., Talmaç, M. A., & Özdemir, H. M. (2026). Comparison of Posterior 2 Rod Instrumentation with 3 Rod Instrumentation in Corrective Spine Fusion Procedures and Risk for Mechanical Failure. Duzce Medical Journal, 28(2), 157-165. https://doi.org/10.18678/dtfd.1878895

AMA

1.Altuntaş Y, Tüter İ, Cam N, Talmaç MA, Özdemir HM. Comparison of Posterior 2 Rod Instrumentation with 3 Rod Instrumentation in Corrective Spine Fusion Procedures and Risk for Mechanical Failure. Duzce Med J. 2026;28(2):157-165. doi:10.18678/dtfd.1878895

Chicago

Altuntaş, Yusuf, İsmail Tüter, Necmi Cam, Mehmet Ali Talmaç, and Haci Mustafa Özdemir. 2026. “Comparison of Posterior 2 Rod Instrumentation With 3 Rod Instrumentation in Corrective Spine Fusion Procedures and Risk for Mechanical Failure”. Duzce Medical Journal 28 (2): 157-65. https://doi.org/10.18678/dtfd.1878895.

EndNote

Altuntaş Y, Tüter İ, Cam N, Talmaç MA, Özdemir HM (August 1, 2026) Comparison of Posterior 2 Rod Instrumentation with 3 Rod Instrumentation in Corrective Spine Fusion Procedures and Risk for Mechanical Failure. Duzce Medical Journal 28 2 157–165.

IEEE

[1]Y. Altuntaş, İ. Tüter, N. Cam, M. A. Talmaç, and H. M. Özdemir, “Comparison of Posterior 2 Rod Instrumentation with 3 Rod Instrumentation in Corrective Spine Fusion Procedures and Risk for Mechanical Failure”, Duzce Med J, vol. 28, no. 2, pp. 157–165, Aug. 2026, doi: 10.18678/dtfd.1878895.

ISNAD

Altuntaş, Yusuf - Tüter, İsmail - Cam, Necmi - Talmaç, Mehmet Ali - Özdemir, Haci Mustafa. “Comparison of Posterior 2 Rod Instrumentation With 3 Rod Instrumentation in Corrective Spine Fusion Procedures and Risk for Mechanical Failure”. Duzce Medical Journal 28/2 (August 1, 2026): 157-165. https://doi.org/10.18678/dtfd.1878895.

JAMA

1.Altuntaş Y, Tüter İ, Cam N, Talmaç MA, Özdemir HM. Comparison of Posterior 2 Rod Instrumentation with 3 Rod Instrumentation in Corrective Spine Fusion Procedures and Risk for Mechanical Failure. Duzce Med J. 2026;28:157–165.

MLA

Altuntaş, Yusuf, et al. “Comparison of Posterior 2 Rod Instrumentation With 3 Rod Instrumentation in Corrective Spine Fusion Procedures and Risk for Mechanical Failure”. Duzce Medical Journal, vol. 28, no. 2, Aug. 2026, pp. 157-65, doi:10.18678/dtfd.1878895.

Vancouver

1.Yusuf Altuntaş, İsmail Tüter, Necmi Cam, Mehmet Ali Talmaç, Haci Mustafa Özdemir. Comparison of Posterior 2 Rod Instrumentation with 3 Rod Instrumentation in Corrective Spine Fusion Procedures and Risk for Mechanical Failure. Duzce Med J. 2026 Aug. 1;28(2):157-65. doi:10.18678/dtfd.1878895