Initial Experience With a Full Endoscopic Facet Fusion in Combination With Endoscopic Interbody Fusion

Abstract

Background Facet fusion has been described in open and minimally invasive approaches to promote fusion. Our objective is to describe the technique of an endoscopic facet decortication and allograft placement as an adjunct to an interbody fusion. Methodology This was a descriptive analysis of patients who underwent endoscopic interbody fusion combined with facet fusion and percutaneous screw placement. General demographics, clinical presentation, length of stay, follow-up, and outcome were gathered. The technique involves endoscopic access to the Kambin's triangle, discectomy/endplate preparation, expandable cage/allograft insertion, and percutaneous pedicle screw placement. A midline incision was performed, and the endoscope was advanced over the facet joints at the desired level. After removing the soft tissue with grasping forceps, cautery was used to disrupt the facet capsule. An articulating high-speed bur was used to drill inside and over the dorsal surface of the joint. Finally, allograft chips were placed through the endoscope cannula. Results From May 2019 to December 2019, four patients underwent endoscopic interbody fusion. All were female, with a mean age of 67.5 years (SD: 12.7). All had chronic low back pain and radiculopathy associated with Grade 1 spondylolisthesis. Two (50%) of the patients underwent two-level fusion. The median hospital stay was two days. Two (50%) reported improvement of both low back and radiculopathy symptoms. None of the patients had a significant complication or required reoperation in eight months' mean follow-up. Conclusions Facet decortication and allograft placement are feasible using an endoscopic approach in conjunction with interbody fusion.

Keywords: endoscopy; lumbar degenerative disease; lumbar fusion; minimally invasive spine.

Figure 1. Endoscopic view of the right facet preparation.

(A) Use of endoscopic bipolar to disrupt the capsule of the joint. (B) Visualization of the facet joint after removal of soft tissue. (C and D): Articulated burr is used in different directions over and within the facet joint to prepare the fusion bed before grafting.

Figure 2. Articulating endoscopic burr.

(A) In neutral. (B) In angulated position

Figure 3. Illustration of the facet preparation and grafting using an endoscopic approach.

(A) Endoscopic grasping forceps are used to remove soft tissue and the articular capsule. (B) Endoscopic bipolar is used to penetrate and disrupt the capsule. (C) (oblique view) and D (axial view): Articulating burr is used to drill and prepare the osseous and intraarticular facets before grafting. (E) Allograft is placed into and over the facet joint using the endoscopic dilator’s back end to push it through the endoscopic cannula.