655 - Self-adapting ALIF Cage Restores Sagittal Balance and Improves Functio...

General Session: Spinal Innovation

Presented by: J.C. le Huec - View Audio/Video Presentation (Members Only)

Author(s):

J.C. le Huec(1), F. Jabbour(2), M. Campana(2), J. Rigal(2), A. Cogniet(2)

(1) Bordeaux University Hospital, Orthorachis (2) , Bordeaux, France
(2) Bordeaux University Hospital, Bordeaux, France

Abstract

Introduction: Loss of lordosis can lead to CLBP, sagittal imbalance and following adjacent segment degeneration. Therefore restoration of sagittal balance should be an everyday concern for the spine surgeon. Asymptomatic volunteers have been found to have L5/S1 lordotic angles at mean 14 degrees, SD 5.9 (Le Huec & Hasegawa). To cope with the individual physical and anatomic variations, a cage for the L5/S1 level providing a self-adapting lordodic angle seems like an attractive concept.

Aim: To prospectively analyze the clinical performance of a novel self-adaptable ALIF cage, the Statur-L (FBC Device). The two-piece articulating cage adapts naturally in situ, permitting from 7-21˚ of lordosis (> 95% of the normal population). This is done without change of components, external adjustment of components or insertion of additional components. Following adaptation, the segment is fixed with an anterior lumbar plate, in the normal fashion.

Material and Methods: It is a one-year prospective consecutive study, including the first 30 ALIF patients. Mean age was 44 years (30-67). There were 17 women and 13 men, and 8 patients had previous disc surgery. All Statur-L surgeries occurred at L5/S1. After insertion of the ALIF cage, an anterior anatomic lumbar plate (Pyramid, Medtronic) was used to fix the segment. Standard radiographic imaging in standing position, MRI and functional follow-up was performed preoperatively and at regular intervals through one year (fusion, subsidence, implant failure, L5/S1 lordosis (SL), VAS back and leg, ODI, SF36). CT scan were performed to confirm the bone bridging. Follow-up rate at one-year 100%

Results: The VAS back pain improved from median 6.3 to 1.4 (p< 0.000) and VAS leg pain from median 4.9 to 0 (p< 0.000). The ODI score improved from median 43 to 9 (p< 0.000). The SF36 PCS improved from median 32.8 to 45.4 (p< 0.000) and MCS improved 38.1 to 51.8 (p< 0.000). All 30 cases were classified as fused at one-year follow-up, and no measurable subsidence could be identified on X-ray or CT. There were no implant failures or reoperations. The pre-operative mean SL was 6.3˚ (SD 2.7) and at one-year follow-up 15.4˚ (SD 2.6) (p< 0.000). The pre-operative mean L5/S1 disc height was 3.7 (SD 2.1) and at one-year follow-up 10.1 (SD 2.3) (p< 0.000). At one-year follow-up the patients had a mean LL (L1-S1) lordosis of 53.9 ˚ (SD 8,8). LL theoretical lordosis was estimated to mean 52.6 (SD 5.6), and published normal population value has been found to be 55.8 (SD 10.2). The lumbar shape was harmonious with an apex at L4 as requested in Roussouly's classification, and global balance was excellent using TPA, SSA and FBI index.

Conclusion: The ALIF cage was found easy to use, and no complications have been identified. The average lordotic correction was 9 degrees and mean L5/S1 SL at one year was 15 degrees, which is approaching normality values found in the literature. All cases fused, and no measurable subsidence was identified. The patient-based outcome shows significant improvement in in both pain, daily function and life quality. This self-adapting ALIF cage allowed to adapt the L5/S1 lordosis contour to each patient anatomy and helps to restore general balance parameters.