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Background: Pedicle screw loosening and breakage are common causes of revision surgery after lumbar fusion. Thus, there remains a continued need for supplemental fixation options that offer immediate stability without the associated failure modes. This finite element analysis compared the biomechanical properties of a novel cortico-pedicular posterior fixation (CPPF) device with those of a conventional pedicle screw system (PSS). Methods: The CPPF device is a polyetheretherketone strap providing circumferential cortical fixation for lumbar fusion procedures via an arcuate tunnel. Using a validated finite element model, we compared the stability and load transfer characteristics of CPPF to intact conditions under a 415 N follower load and PSS conditions under a 222 N preload. Depending on the instrumented levels, two different interbody devices were used: a lateral lumbar interbody device at L4–5 or an anterior lumbar interbody device at L5-S1. Primary outcomes included range of motion of the functional spinal units and anterior load transfer, defined as the total load through the disk and interbody device after functional motion and follower load application. Results: Across all combinations of interbody devices and lumbar levels evaluated, CPPF consistently demonstrated significant reductions in flexion (ranging from 90 to 98%), extension (ranging from 88 to 94%), lateral bending (ranging from 75 to 80%), and torsion (ranging from 77 to 86%) compared to the intact spine. Stability provided by the CPPF device was comparable to PSS in all simulations (range of motion within 0.5 degrees for flexion–extension, 0.6 degrees for lateral bending, and 0.5 degrees for torsion). The total anterior load transfer was higher with CPPF versus PSS, with differences across all tested conditions ranging from 128 to 258 N during flexion, 89–323 N during extension, 135–377 N during lateral bending, 95–258 N during torsion, and 82–250 N during standing. Conclusion: Under the modeled conditions, cortico-pedicular fixation for supplementing anterior or lateral interbody devices between L4 and S1 resulted in comparable stability based on range of motion measures and less anterior column stress shielding based on total anterior load transfer measures compared to PSS. Clinical studies are needed to confirm these finite element analysis findings. [ABSTRACT FROM AUTHOR]

Background: Minimally invasive lateral approaches to the lumbar spine have been adopted to allow access to the intervertebral disc space while avoiding the complications associated with anterior or posterior approaches. This report describes a minimally invasive technique for lateral lumbar interbody fusion LLIF that allows direct intraoperative visualization of the psoas and surrounding neurovasculature (DV-LIF). Methods: The technique utilizes a radiolucent tubular retractor and a secondary psoas retractor that allows a muscle-sparing approach while offering excellent visualization of the operative site. The unique advantage of this procedure is that the psoas muscle and surrounding nerves can be directly visualized intraoperatively to supplement neuromonitoring. We retrospectively reviewed complication rates in 34 patients treated with DV-LLIF (n = 19) or standard lateral lumbar interbody fusion (S-LLIF, n = 15). Results: There were 29 complications (median: 1 per patient) with DV-LLIF and 20 (median: 1 per patient) complications with S-LLIF. Postoperative sensory deficits were reported in eight (42%) and seven (47%) patients, respectively. Thigh pain or numbness was reported in eight (42%) and five (33%) patients, respectively. The percentage of the overall complications directly attributable to the procedure was 69% with DV-LLIF and 83% with S-LLIF. One severe complication (back pain) was reported in one DV-LLIF patient and four severe complications (severe bleeding, respiratory failure, deep venous thrombosis and gastrointestinal prophylaxis, and nicked renal vein and aborted procedure) were reported in two S-LLIF patients. Conclusions: Preliminary evidence suggests that minimally invasive lateral interbody fusion with direct psoas visualization may reduce the risk for severe procedural complications. [ABSTRACT FROM AUTHOR]

The author discusses a meta-analysis that examined randomized controlled trials comparing minimally-invasive versus open approaches to transforaminal lumbar interbody fusion (TLIF). Topics include samples of text that identifies each as a non-randomized study, errors made by the authors in the classification of the included studies, and the association between minimally-invasive TLIF and a shorter hospital stay relative to open TLIF.