Single-position surgery finally gets its due.

I recently returned from the 2021 Society for Minimally Invasive Spine Surgery (SMISS) meeting in Las Vegas.  This meeting, dedicated to advanced, innovative topics in minimally-invasive and lateral access spinal surgery, is probably the best meeting of the year for minimally-invasive spine (MIS) surgeons (i.e. the only type of spine surgeon you should ever visit.)  Our group presented three very important studies on single-position surgical (SPS) strategies in spine surgery (a group is typically allowed to present no more than two studies but the meeting organizers allowed an extra presentation only for our group given the strength of our data (as presented by the outstanding 6th year NYU neurosurgical resident Kimberly Ashayeri, MD, see image 1.)  5 years ago, when my friend Brian Kwon and I were the only surgeons talking about SPS at these meetings, to say that it wasn’t received positively would be very generous (I still vividly remember getting yelled at by some of the most renowned MIS surgeons).  A few years later when we were the first to use the term “single-position” in the spine literature it still didn’t get much attention.  Now, it seems like all anyone wanted to talk about this year at the SMISS meeting was SPS in one form or another.  With our presentations at the meeting and recent related major publications we continue to demonstrate the tremendous power and value of SPS.  And now everyone is paying attention. 

Image 1: NYU neurosurgery resident Kimbery Ashayeri presents our 1-year data comparing SPS techniques with traditional dual-position techniques at the 2021 SMISS meeting.  

Briefly, single-position surgery (SPS) is an emerging concept that describes a surgical strategy that allows the placement of large
spacers in the front of the spine and pedicle screw fixation at the back of the spine all without repositioning the patient.  Traditionally, after an XLIF the surgeon would close the flank incision and the patient would then be positioned prone (face down) for placement of the pedicle screws (surgeons are classically taught to place pedicle screws in the prone position so this is more familiar to them).  This subjects the patient to significantly more anesthesia time for each “flip”, not to mention the increased risks of moving an a patient who’s asleep (i.e. inadvertently pulling out the breathing tube or IVs.)  If the surgeon also wishes to do an anterior lumbar interbody fusion (ALIF) at L5/S1, which is traditionally done with the patient in the supine position (on their back), prior to the XLIF at L4/5 that’s one more “flip” for the patient.  Patients with degenerative pathology of their spine commonly need fusion from L4-S1. Think about how long that could take:  ALIF at L5/S1, close, flip; XLIF at L4/5, close, flip; bilateral pedicle screw fixation, close.  Spine surgeons call this the rotisserie and it can take hours (see image 2). Using SPS, however, we are now able to do these cases in 70-90 minutes.  The surgeon no longer must sacrifice placing a large intervertebral spacer for the sake of expediency (as in the abominable TLIF procedure).  (See image 3)

Image 2: traditional anterior-posterior spinal procedures can involve multiple “flips” between stages of the surgery.  This results in more time under anesthesia and thus increased risk for the patient.  

Image 3: Another benefit of keeping the patient in the lateral position for the entirety of the case is that you have concurrent access to the front and back of the patient.  Here, our approach surgeon Dr. Medley (right of screen) completes the abdominal portion of the case at the front of the patient while I place pedicle screw fixation at the back of the patient (left of screen).  By working simultaneously during these case we are able to save the patient over an hour of time under anesthesia.

Not since the advent of XLIF have I seen such a game-changer as SPS and it was pioneered in large part by us right here in Wilmington, NC (cue Southern accent: “I’m just a small-town country neurosurgeon…”).  Anyone who has read my posts on Spinal(con)Fusion knows that I never use this as a forum for self-promotion and that’s not what I’m doing here.  Not all spine surgery is the same, though, and my mission is to make sure patients know that.  SPS is changing spinal fusion surgery and patients right here in the Eastern North Carolina have been some of the first to benefit.

The next several posts are going to be dedicated to discussing single-position surgery. We’ll discuss how the concept was first conceived to simply save OR time during XLIF procedures.  We’ll discuss how we solved the issue of access to L5/S1 while keeping the patient in the lateral position. Lastly, we’ll discuss the evidence from several large multi-center studies (for which we contributed a significant amount of patient data) that demonstrates that not only does SPS dramatically improve OR efficiency but that this increased efficiency leads to significantly improved patient outcomes.  It’s been quite the journey and I can’t wait to tell you about it.

Thanks for reading.

J. Alex Thomas, M.D.