Name:
10.3171/2022.3.FOCVID2216
Description:
10.3171/2022.3.FOCVID2216
Thumbnail URL:
https://cadmoremediastorage.blob.core.windows.net/7fdac64a-7380-4323-894d-dd7b786a2013/videoscrubberimages/Scrubber_256.jpg
Duration:
T00H06M38S
Embed URL:
https://stream.cadmore.media/player/7fdac64a-7380-4323-894d-dd7b786a2013
Content URL:
https://cadmoreoriginalmedia.blob.core.windows.net/7fdac64a-7380-4323-894d-dd7b786a2013/9. 22-16.mp4?sv=2019-02-02&sr=c&sig=JpaTqJBHkJSRkgAwO9rYOyNKBVA4skFHywWY2Flstk8%3D&st=2024-04-29T10%3A43%3A33Z&se=2024-04-29T12%3A48%3A33Z&sp=r
Upload Date:
2022-05-31T00:00:00.0000000
Transcript:
Language: EN.
Segment:0 .
[MUSIC PLAYING]
SPEAKER: The lateral lumbar interbody fusion has evolved as newly envisioned access corridors become feasible via technological advances. Prone lateral access emerged as a single-position approach to combine the benefits of minimally invasive surgery with direct and indirect decompression of the neural elements via synergistic anterior and posterior column correction. As our experience with this approach has evolved, so has our understanding of the challenges inherent in single- position surgery.
SPEAKER: In this video, we discuss the pearls, pitfalls, and adjuvant technologies we use in a high-volume prone lateral center. Choosing anatomically ideal candidates for prone lateral access requires evaluation of plane films in quality MRIs. As with all surgeries, safe access is predicated on knowledge of the structures in and around the operative corridor.
SPEAKER: In this, prone lateral surgeons are required to adopt a general surgeon mentality when evaluating the retroperitoneal space, assessing local vasculature and neural elements. Bony anatomy, including vertebral body shape, transitional levels, and iliac crest morphology, are also necessary to generate a 3D understanding of the access corridor. Throughout this video, several themes will emerge that significantly improve prone lateral access workflow.
SPEAKER: 1) Efficient use of fluoroscopy, which significantly improves workflow as the access corridor is most familiar in a true parallel-to-floor position. 2) Maintaining a healthy respect for gravity. Gravity's pull can both help and harm access, benefiting retroperitoneal dissection while pulling the docking system suboptimally downward. Careful attention to shim placement in this position is therefore important.
SPEAKER: Our use of saphenous SSEP mitigates damage from lumbar plexus traction in the lateral position. Damage to anterior structures is mitigated with optimal positioning, time spent understanding imaging, and awareness of gravitational forces. We will discuss the pearls and pitfalls for the prone lateral corpectomy through a case example. The patient is a 68-year-old female who sustained a ground-level fall 4 months prior, now presenting with severe low-back pain and shooting pains down her right buttock and leg.
SPEAKER: Physical examination revealed no gross abnormalities in strength or sensation, marked tenderness to the mid-lower back, and a general inability to ambulate due to pain. MRI and x-ray from the outside hospital revealed a burst fracture at lumbar 3, causing right centric compression of the thecal sac and exiting nerve roots without gross disturbance of lumbar lordosis.
SPEAKER: Given her overall clinical picture and imaging findings, she was determined to be a candidate for a prone lateral corpectomy with posterior decompression and fusion across the corpectomy level. For the purposes of this video, we will focus on the first two components of the procedure. The patient is positioned prone, as demonstrated on this cadaveric model.
SPEAKER: Note the custom bolsters in tape simultaneously resisting lateral forces while allowing manual distraction of the rib-hip angle. Also note the strict parallel orientation to the floor. This is critical for the access surgeon to internalize, especially if slight oblique angulation is necessary for ergonomic ease. The ribs and iliac crest are marked. The planned incision is placed slightly posterior to a typical LLIF incision in order to account for gravity.
SPEAKER: This can either be found with preplanned robotic navigation or fluoroscopy. Here we demonstrate incision marking via the latter. A line is made through the midpoint of the disc space, followed by the posterior, then midpoint, of the vertebral body. The incision is then marked as a diagonal along a natural Langer line. Retroperitoneal access is made with sweeping motions, feeling for the iliac crest inferiorly as a guide point. A posterior-to- anterior trajectory is safest, pushing the abdominal contents with gravity downward rather than lateral. Palpation of the transverse process confirms medial extent and the initial dilator is then passed over the docked hand. Position at the disc space is confirmed on AP and lateral fluoroscopy. This is then held with a K-wire.
SPEAKER: Directional EMG is then used to guide dilation. Once satisfied, the access system is then placed over the final dilator in a similar fashion and then docked to the patient. Spot fluoroscopy is performed to confirm the site. Directional EMG then again confirms the position. The first view into the working corridor is now seen, ideally an endplate-to-endplate view with the posterior disc space in sight.
SPEAKER: The retractor is carefully opened to maximize this corridor. We also use saphenous SSEP as an adjunctive gauge for timely retractor removal. We found that this better approximates neural injury over standard posterior tibial SSEPs given that the femoral nerve is at a higher risk of apraxia during this approach. We now localize for our corpectomy, confirming our disc spaces superiorly and inferiorly.
SPEAKER: The discectomy is performed efficiently with care to maintain an orthogonal trajectory and to not push through the contralateral annulus. Vertebral body is also carefully removed under fluoroscopic guidance. The trial is sized and the implant is placed and expanded. Perc screws are performed in standard fashion with the lateral incision kept open in case extra extension of the cage is necessary after posterior distraction.
SPEAKER: In this case, no adjustments were made. The patient was discharged on postoperative day 6, ambulating with a front-wheeled walker without new neurologic deficit. Postoperative films are shown here. Careful preoperative planning, knowledge of technology available, and capacity to mitigate inherent procedural pitfalls will continue to allow surgeons to maximize the prone lateral corridor for lumbosacral pathology.
SPEAKER: