Single-position spine surgery: One position, a multitude of advantages

In recent years, the orthopedic community’s interest in single-position spine surgery has been steadily increasing, and for good reason. Dr. Raymond Hah and Dr. Ram Alluri discuss why this technique has become a mainstay of their practice and advise any surgeons aspiring to perform single-position spine surgery on how to get started.

As a primer, let’s clarify what we mean when we talk about single-position spine surgery. Spinal fusion surgeries typically involve interbody placement in either the supine or lateral decubitus position followed by adjustment of the patient into the prone position for instrumentation. However, with the single-position technique the patient remains in a lateral decubitus or prone position throughout the surgery. We initially explored the lateral single-position approach at USC as it is an elegant procedure that overcomes various issues associated with other approaches. Of note, single-position approaches have been described using various terminologies including oblique lumbar inter-body fusion, extreme lateral interbody fusion, and direct lateral interbody fusion.

Single-position surgery solves inefficiencies and shortens time in theatre

In general, there are several advantages to single-position surgery but the major driver that pushed us to start exploring the technique was deformity correction operations.

As a deformity surgeon the rule is, if you're not thinking about deformity, you're probably creating it. In that sense, the single-position approach provides a great solution in terms of patient safety and efficiency, this is from both a short- and a long-term perspective when considering alignment needs and adjacent pathology. For those operations where multiple interspaces are treated it is particularly advantageous not to have to flip the patient. Take an L5-S1 anterior lumbar interbody fusion (ALIF) for example, where the patient needs to be turned laterally for additional work. The days where we would perform a big abdominal incision to get L2-S1 anteriorly are long gone due to the high morbidity risk for the patient, so ultimately it was in exploring ways to solve that inefficiency that we began to look at single-position surgery.

A major advantage of the single-position technique is that you save time in theatre. If you work on a case where the position changes, you wait a long time for turnover and then if you add a flip in there, it can be equivalent to three cases, which makes for a long day at a big university. Using the single-position technique, you are able to treat a 5-1 disc in the lateral position with the lateral ALIF, then work up the lateral aspect of the spine and do multi-level laterals and avoid an additional flip. Single-position surgery has changed our ability to finish a deformity case in a day, as opposed to having to stage it and bring patients back the next day which is why we’re very passionate about the technique.

A recent study completed by the orthopedic team at New York University backs up our experience1. The study reported that with a traditional lateral position and instrumentation in the prone position, it takes an additional two hours to flip the patient. Two hours is effectively an additional case. Therefore, if you can do the surgery in one position, you're able to treat more patients. If you add that up over the course of a year, it's significant.

Additional benefits from deformity to degeneration cases

With single-position surgery, it's not only the elimination of the position change that saves time. A key time saver comes from being able to work concomitantly with your team and other specialists, instead of having them wait around for repositioning. For example, when working alongside a vascular team, it’s possible to begin some of the lateral work while they're doing their anterior exposure.

If we're flipping for screws, it’s possible to instrument L3-1, L2-S1 in the lateral position if there's no need for osteotomies. The orthopedic surgeon can therefore be cannulating pedicles while the vascular surgeon works on the anterior. Once the vascular surgeon is finished, we are able to complete the anterior work and then proceed to do the laterals as well. In our experience, most of the time savings arise when the vascular surgeon is closing an anterior incision. With regards to the orthopedic team, you can have someone performing the retroperitoneal access while you have your fellow or co-surgeon on the other side of the table actively decompressing, or you can have them actively putting in screws while you're putting in the cage.

We track outcomes closely at our center and have observed additional advantages to using the single-position approach. Our experience, backed by data from the literature, shows us that single-position surgery results in a valuable decrease in anesthesia time, less postoperative issues, earlier postoperative recovery, and a shorter length of stay for the patient2. Another aspect to consider is that with any position change you’re increasing the chance of sterility problems and consequentially the potential for increased infection.

Therefore, from a patient perspective, single-position surgery really makes sense. At our center we perform a lot of minimally invasive (MIS) transforaminal lumbar interbody fusions (TLIF). It's unusual to send a MIS TLIF patient home in less than 24 hours. With ALIFs, often two-level or even one-level ALIFs are in the hospital three or four days due to ileus and retroperitoneal swelling. Patients undergoing a one level lateral fusion with single-position screws routinely go home within 24 hours.
Following our successful experience with deformity correction, we expanded our use of the single-position technique to degenerative cases. In this setting, a real benefit of the single-position technique has been a reduction in repeated TLIFs and the need to take care of patients posteriorly.

Thanks to fluoroscopic guidance and the use of navigation techniques, we are able to safely and reproducibly put screws into the lateral position. This has been a game changer because without that, there is a high threshold to work laterally and then flip to do the work in the back; it’s common to hear surgeons say that perhaps it’s better to rather go ahead with a TLIF instead. However, when you get to the point where you believe the indirect decompression is powerful and real if carefully selected and that you can do this in a single position, it really changes the way that you view clinical problems.