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Global Spine J
Global Spine J
spgsj
GSJ
Global Spine Journal
2192-5682
2192-5690
SAGE Publications Sage CA: Los Angeles, CA

10.1177_21925682241227412
10.1177/21925682241227412
Letters to the Editor
Reply to “Letter to the Editor Concerning ‘Implant-Related Complications After Spinal Fusion: A Multicenter Study.’ by Koshimizu et al.”
Koshimizu Hiroyuki MD, PhD 1
https://orcid.org/0000-0002-0039-9678
Nakashima Hiroaki MD, PhD 1
Ohara Tetsuya MD 2
Tauchi Ryoji MD, PhD 2
Kanemura Tokumi MD, PhD 3
Shinjo Ryuichi MD, PhD 4
Machino Masaaki MD, PhD 1
Ito Sadayuki MD, PhD 1
https://orcid.org/0000-0002-1088-2903
Ando Kei MD, PhD 1
https://orcid.org/0000-0002-6951-8575
Imagama Shiro MD, PhD 1
1 Department of Orthopaedic Surgery, 12965 Nagoya University Graduate School of Medicine , Nagoya, Japan
2 Department of Orthopedic Surgery, Meijo Hospital , Nagoya, Japan
3 Department of Orthopedic Surgery, Konan Kosei Hospital , Konan, Japan
4 Department of Orthopaedic Surgery, Anjo Kosei Hospital , Anjo, Japan
Hiroaki Nakashima, MD, PhD, Department of Orthopaedic Surgery, Nagoya University Graduate School of Medicine 65, Tsurumai, Showa-ku, Nagoya, Aichi, 466-8550, Japan. Email: hirospine@med.nagoya-u.ac.jp
17 1 2024
6 2024
14 5 16821683
© The Author(s) 2024
2024
AO Spine, unless otherwise noted. Manuscript content on this site is licensed under Creative Commons Licenses
https://creativecommons.org/licenses/by-nc-nd/4.0/ This article is distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 License (https://creativecommons.org/licenses/by-nc-nd/4.0/) which permits non-commercial use, reproduction and distribution of the work as published without adaptation or alteration, without further permission provided the original work is attributed as specified on the SAGE and Open Access pages (https://us.sagepub.com/en-us/nam/open-access-at-sage).

typesetterts10
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pmcWe appreciate your interest in our study and value your insightful comments.

As you highlighted, the incidence of complications associated with implants appears to be influenced substantially by osteoporosis along with diabetes and obesity as comorbidities. 1 Previous reports have indicated that osteoporosis can cause screw loosening 2 and cage subsidence, 3 which are pertinent to the occurrence of implant-related complications. Another potential factor is the ossification of the posterior longitudinal ligament, contributing to postoperative complications such as infection due to increased bleeding and surgical challenges. 4 However, our study’s primary focus was on investigating the incidence of implant complications rather than identifying risk factors. We trust that our data will serve as valuable information for informing patients about complication rates.

Regarding screw placement, previous research showed that junior surgeons face an increased risk of screw malposition, emphasizing the significant effect of surgeon experience. 5 Despite this, our study categorized surgeons into two groups, board-certified (BCS) and non-BCS (NBCS) spine surgeons in Japan, and investigated postoperative screw malposition. Surprisingly, we found no significant difference between the two groups. One explanation could be that the accuracy of screw placement improved when nonsupervising surgeons performed the surgery under the guidance of supervising surgeons. However, the limited number of screw malposition cases and potential statistical power insufficiency underscore the need for investigation in the future.

As you rightly highlighted, the use of advanced intraoperative imaging techniques may also influence screw placement accuracy. However, our data are incomplete, preventing us from examining whether intraoperative imaging was used. We acknowledge this as a limitation and sincerely appreciate your valuable input.

ORCID iDs

Hiroaki Nakashima https://orcid.org/0000-0002-0039-9678

Kei Ando https://orcid.org/0000-0002-1088-2903

Shiro Imagama https://orcid.org/0000-0002-6951-8575
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References

1 Schömig F Becker L Schönnagel L et al. Avoiding spinal implant failures in osteoporotic patients: a narrative review. Global Spine J. 2023;13 (1 Suppl ):52S-58S. doi:10.1177/21925682231159066 37084355
2 Rometsch E Spruit M Zigler JE et al. Screw-related complications after instrumentation of the osteoporotic spine: a systematic literature review with meta-analysis. Global Spine J. 2020;10 (1 ):69-88. doi:10.1177/2192568218818164 32002352
3 Oh KW Lee JH Lee J-H Lee D-Y Shim HJ . The correlation between cage subsidence, bone mineral density, and clinical results in posterior lumbar interbody fusion. Clin Spine Surg. 2017;30 (6 ):E683-E689. doi:10.1097/BSD.0000000000000315 28632554
4 Ramos MRD Liu G Tan J-H et al. Risk factors for surgical complications in the management of ossification of the posterior longitudinal ligament. Spine J. 2021;21 (7 ):1176-1184. doi:10.1016/j.spinee.2021.03.022 33775844
5 Gonzalvo A Fitt G Liew S et al. The learning curve of pedicle screw placement: how many screws are enough? Spine (Phila Pa 1976). 2009;34 (21 ):E761-E765. doi:10.1097/BRS.0b013e3181b2f928 19934796
