Spinal Alignments of Residual Lumbar Curve Affect Disc Degeneration after Spinal Fusion in Patients with Adolescent Idiopathic Scoliosis: Follow-up after 5 or More Years

Tsutomu Akazawa; Tasuku Umehara; Masahiro Iinuma; Kota Asano; Shingo Kuroya; Yoshiaki Torii; Kenichi Murakami; Toshiaki Kotani; Tsuyoshi Sakuma; Shohei Minami; Sumihisa Orita; Kazuhide Inage; Yasuhiro Shiga; Junichi Nakamura; Gen Inoue; Masayuki Miyagi; Wataru Saito; Yawara Eguchi; Kazuki Fujimoto; Hiroshi Takahashi; Seiji Ohtori; Hisateru Niki

doi:10.22603/ssrr.2019-0048

Spinal Alignments of Residual Lumbar Curve Affect Disc Degeneration after Spinal Fusion in Patients with Adolescent Idiopathic Scoliosis: Follow-up after 5 or More Years

Spine Surg Relat Res. 2019 Aug 16;4(1):50-56. doi: 10.22603/ssrr.2019-0048. eCollection 2020.

Authors

Tsutomu Akazawa^{1

2}, Tasuku Umehara¹, Masahiro Iinuma¹, Kota Asano¹, Shingo Kuroya¹, Yoshiaki Torii¹, Kenichi Murakami¹, Toshiaki Kotani², Tsuyoshi Sakuma², Shohei Minami², Sumihisa Orita³, Kazuhide Inage³, Yasuhiro Shiga³, Junichi Nakamura³, Gen Inoue⁴, Masayuki Miyagi⁴, Wataru Saito⁴, Yawara Eguchi^{3

5}, Kazuki Fujimoto^{3

6}, Hiroshi Takahashi⁷, Seiji Ohtori³, Hisateru Niki¹

Affiliations

¹ Department of Orthopaedic Surgery, St. Marianna University School of Medicine, Kawasaki, Japan.
² Department of Orthopedic Surgery, Seirei Sakura Citizen Hospital, Sakura, Japan.
³ Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan.
⁴ Department of Orthopaedic Surgery, Kitasato University School of Medicine, Sagamihara, Japan.
⁵ Department of Orthopaedic Surgery, National Hospital Organization, Shimoshizu Hospital, Yotsukaido, Japan.
⁶ Department of Orthopaedic Surgery, Konodai Hospital, National Center for Global Health and Medicine, Ichikawa, Japan.
⁷ Department of Orthopaedic Surgery, Toho University Sakura Medical Center, Sakura, Japan.

Abstract

Introduction: Despite preserving lumbar disc mobility, spinal sagittal, and/or coronal alignment might ultimately impede surgical success. The purpose of this study was to elucidate the effects of spinal alignment on lumbar disc degeneration after 5 or more years in adolescent idiopathic scoliosis (AIS) patients who underwent spinal fusion.

Methods: Subjects were 49 AIS patients who underwent posterior spinal fusion without lumbar curve fusion. The inclusion criteria were the following: 1) Lenke type 1A, 1B, 2A or 2B, 2) age 10 to 19 years at the time of operation, and 3) minimum 5-year follow-up. The exclusion criteria were the following: 1) diagnosed as other than AIS, 2) history of lumbar disc herniation and spondylolysis, 3) subsequent surgery, and 4) history of surgery before AIS surgery. Nineteen patients agreed to participate in this research. X-rays, lumbar MRI, and questionnaires were evaluated. Disc degeneration in non-fused segments was defined as Pfirrmann grade 3 or higher. Patients with disc degenerations at the final observation (DD[+] group) were compared to those without disc degenerations (DD[-] group).

Results: There were no significant differences in the preoperative or postoperative 1-week X-ray parameters between both groups. The lumbar curve was significantly larger in the DD[+] group compared with the DD[-] group at the final observation (DD[+]: 16.8 degrees, DD[-]: 10.4 degrees, p = 0.035). The sagittal vertical axis (SVA) was significantly larger in the DD[+] group compared with the DD[-] group at the final observation (DD[+]: -4.4 mm, DD[-]: -34.3 mm, p = 0.006). SRS-22 function, self-image, and satisfaction scores were lower in the DD [+] group compared with the DD[-] group at the final observation.

Conclusions: The patients with DD had significantly larger lumbar curve and SVA with lower SRS-22 function, self-image, and satisfaction scores at the final observation. Even though the non-fused segments were preserved, spinal alignments of non-fused lumbar curve affect the DDs.

Keywords: adolescent idiopathic scoliosis; disc degeneration; long-term follow-up; selective thoracic fusion.