Abstract
Background Endoscopic lumbar interbody fusion using a cage can have a similar fusion rate as
minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) or open lumbar
interbody fusion. Direct visual control during cage insertion is the key to prevent
neural structure incarceration in endoscopic lumbar interbody fusion. Creating a track
with any kind of retractor or cannula for cage insertion under fluoroscopic guidance
is not safe enough, because the retractor and cannula can create many blind spots
and can displace during cage insertion.
Method The pin method utilizes two flexible metallic guide pins inserted from the skin incision
through the annulotomy site into the disk space until the anterior longitudinal ligament
is reached under direct endoscopic monitoring. The two guide pins could be oriented
parallel or perpendicular or even reduce to one or increase to many as needed to serve
as a sliding track and a see-through barrier to prevent neural incarceration.
Results and Conclusion Two cases of L4/L5 grade 2 spondylolisthesis with neurogenic claudication were treated
with endoscopic lumbar interbody fusion with 1-year follow-up, and the visual analog
scale (VAS) score, Oswestry Disability Index (ODI) score, EuroQol five-dimensional
questionnaire (EQ-5D, %) score, and modified Macnab score all improved greatly in
both. The author developed an original, cheap, accessible, and safe method called
the “pin method,” which can be used in both full-endoscopic and biportal surgery and
can apply to various approaches and has no limitation on the size and shape of the
cage.
Keywords
endoscopy - interbody fusion - lumbar - transforaminal - biportal
