Abstract
Background Lumbar lordosis distribution has become a pivotal factor in re-establishing the foundational alignment of the lumbar spine. This can directly influence overall sagittal alignment, leading to improved long-term outcomes for patients. Despite the wide availability of hyperlordotic stock cages intended to achieve optimal postoperative alignment, there is a lack of correlation between the lordotic shape of a cage and the resultant intervertebral alignment. Recently, personalized spine surgery has witnessed significant advancements, including 3D-printed personalized interbody implants, which are customized to the surgeon’s treatment and alignment goals. This study evaluates the reliability of 3D-printed patient-specific interbody implants to achieve the planned postoperative intervertebral alignment.
Methods This is a retrospective study of 217 patients with spinal deformity or degenerative conditions. Patients were included if they received 3D-printed personalized interbody implants. The desired intervertebral lordosis (IVL) angle was prescribed into the device design for each personalized interbody (IVL goal). Standing postoperative radiographs were measured, and the IVL offset was calculated as IVL achieved minus IVL goal.
Results In this patient population, 365 personalized interbodies were implanted, including 145 anterior lumbar interbody fusions (ALIFs), 99 lateral lumbar interbody fusions (LLIFs), and 121 transforaminal lumbar interbody fusions. Among the 365 treated levels, IVL offset was 1.1° ± 4.4° (mean ± SD). IVL was achieved within 5° of the plan in 299 levels (81.9%). IVL offset depended on the approach of the lumbar interbody fusion and was achieved within 5° for 85.9% of LLIF, 82.6% of transforaminal lumbar interbody fusions and 78.6% of ALIFs. Ten levels (2.7%) missed the planned IVL by >10°. ALIF and LLIF levels in which the plan was missed by more than 5° tended to be overcorrected.
Conclusions This study supports the use of 3D-printed personalized interbody implants to achieve planned sagittal intervertebral alignment.
Clinical Relevance Personalized interbody implants can consistently achieve IVL goals and potentially impact foundational lumbar alignment.
Level of Evidence 4.
Footnotes
Funding This work was supported by funding from Carlsmed.
Declaration of Conflicting Interests Saeed S. Sadrameli discloses that he receives consulting fees from Carlsmed. Donald J. Blaskiewicz discloses that he is a clinical research investigator and receives consulting fees from Carlsmed. Christopher P. Ames discloses that he is a clinical research investigator and receives consulting fees from Carlsmed. Jahangir Asghar discloses that he is a clinical research investigator and receives consulting fees from Carlsmed. Gregory M. Mundis discloses that he receives consulting fees from Carlsmed. Joseph A. Osorio discloses that he is a clinical research investigator and receives consulting fees from Carlsmed. Justin S. Smith discloses that he is a shareholder and receives consulting fees from Carlsmed. Sigurd H. Berven discloses that he receives consulting fees from Carlsmed. Chun-Po Yen discloses that he is a clinical research investigator and receives consulting fees from Carlsmed. Ashvin I. Patel discloses that he is a clinical investigator and receives consulting fees from Carlsmed. Michele Temple-Wong discloses that she is an employee of Carlsmed. Rodrigo J. Nicolau discloses that he is an employee of Carlsmed. Roland S. Kent discloses that he is a clinical research investigator and receives consulting fees from Carlsmed.
Disclosures In addition to the relationships listed in the Declaration of Conflicting Interests, Christopher Ames reports grants/contracts from SRS; royalties/licenses from DePuy Synthes, K2M, Next Orthosurgical, Stryker, Biomet Zimmer Spine, Medicrea, and NuVasive; consulting fees from DePuy Synthes, Medicrea, Agada Medical, Medtronic, and K2M; is the chair of the SRS Safety and Value Committee and serves on the executive committee of ISSG; serves on the editorial board for Operative Neurosurgery and Neurospine; is the director of Global Spinal Analytics, and has research interests with Titan Spine, ISSG, and DePuy Synthes. Sigurd Berven reports royalties/licenses from Elsevier, Medtronic, and Stryker; consulting fees from Medtronic, SI Bone, Innovasis, Globus, and Camber Spine; and stock/stock options from Globus, Green Sun Medical, and Novapproach. Roland Kent reports consulting fees from SI Bone and Globus Medical; payment/honoraria from SI Bone, Globus Medical, and Premia Spine; and patents pending for SI Bone. Gregory Mundis reports royalties/licenses from NuVasive, Seaspine, and Stryker; consulting fees from Seaspine and SI Bone; participating on data safety monitory board or advisory board from NuVasive and Seaspine; leadership role in Global Spine Outreach, San Diego Spine Foundation, and San Diego Orthopaedic Society; and stock/stock options with Alphatec Seaspine, NuVasive, and Orthofix. Joseph Osorio reports grants/contracts from Medtronic; royalties/licenses from Alphatec; and consulting fees from Alphatec, Medtronic, and DePuy. Justin Smith reports grants/contracts from SeaSpine/Orthofix, NREF, AO Spine, and DePuy Synthes/ISSGF; royalties/licenses from Highridge and Globus/NuVasive; consulting fees from Highridge, SeaSpine/Orthofix, Medtronic, Cerapedics, and Globus/NuVasive; support for attending meetings/travel from AO Spine; serving on the SRS Board of Directors and ISSGF Executive Committee; and stock/stock options from Alphatec and Globus/NuVasive. Chun-Po Yen reports consulting fees from Life Spine and Medtronic and support for teaching a cadaveric course from Life Spine.
Ethics Approval This study utilized secondary research consisting of de-identified data for which consent is not required and was therefore exempt from institutional review board review under 45 CFR §46.104 (d)(4)(ii). No direct patient involvement occurred.
- This manuscript is generously published free of charge by ISASS, the International Society for the Advancement of Spine Surgery. Copyright © 2024 ISASS. To see more or order reprints or permissions, see http://ijssurgery.com.
In this issue
