A novel endoscopic posterior cervical decompression and interbody fusion technique: Feasibility and biomechanical analysis

Abstract

Background and objective

Cervical decompression and fusion, the primary surgical techniques for treating degenerative cervical myelopathy, is traditionally performed using interbody fusion through an anterior approach. There are no reported cases of cage placement performed via a posterior cervical approach under endoscopy. This study investigates a novel posterior interbody fusion technique using a newly designed split cage and validates its feasibility through computer simulations.

Methods

Anatomical parameters of the posterior cervical safe area (PCSA) were analyzed, and a split interbody fusion cage was designed based on the anatomical parameters for endoscopic posterior cervical decompression and interbody fusion (Endo-PCDIF) surgery. Based on a validated intact C3-C7 cervical model, decompression-alone and Endo-PCDIF models were established via simulating operations, and comparisons were conducted among these models regarding the range of motions (ROMs), displacement, and stress distribution under the different motion conditions.

Results

PCSA is surrounded by the dural sac, nerve roots, vertebral artery, and pedicle. Ideal operating space for Endo-PCDIF was achieved by grinding the partial osseous structure. After performing decompression-alone, ROMs at the operational segment increased significantly compared to the pre-operation (80%, 12%, 34%, 24%, 25%, and 10%). Endo-PCDIF reduced ROMs at the operational segment by 49%, 32%, 46%, 42%, 52%, and 39% compared to the decompression-alone. The split cage exhibited minimal displacement and no abnormal stress distribution was observed.

Conclusions

PCSA is a crucial surgical pathway for operation at ventral area of dural sac during posterior cervical endoscopy. Endo-PCDIF effectively maintained stability at the operational segment and reduced the biomechanical influence result in adjacent segments.