(I-670) Prospective Multi-Center Comparative Study of the Perioperative Outcomes Associated with the Early “Prone Lateral” Experience Versus “PTP” Proceduralization

Introduction: Prone-position lateral interbody fusion (LIF) has shown feasibility and efficiencies related to single-position surgery. Learnings from early experience led to development of procedure-specific technologies and technique details that differentiate the proceduralized “prone transpsoas (PTP)” from other attempts at “prone lateral” using traditional lateral systems. The current study is a prospective comparative analysis of this evolution via comparison of pre- and post-proceduralization cohorts, hypothesizing that proceduralization increases efficiencies with equivalent peri-op outcomes.

Methods: The pre-proceduralization cohort (ProneLat) included the early multi-center clinical experience wherein procedural details and perioperative outcomes were prospectively captured to assess feasibility, efficiencies, and challenges. A sequential cohort using procedure-specific tools reflecting the demands of operating laterally with the patient prone (PTP) was similarly captured. The results were compared between groups.

Results: ProneLat and PTP cohorts were 120 patients/176 levels and 168 patients/245 levels, respectively. BMI was similar between groups (mean 31, range 18-51); no procedure was abandoned due to body habitus. Procedures spanned from T12-L1 to L4-5, most inclusive of L4-5 (68% vs. 63%, p>0.05). Concomitant posterior procedures were performed equivalently across groups (51% vs. 56%, p>0.05), including direct decompression (34% vs. 31%), inclusion of P/TLIF at L5-S1 (16% vs. 14%), hardware revision (13% vs 18%), and use of osteotomies (7% vs. 4%). Despite treatment similarities, the PTP group saw the following significant time savings: average positioning time by 22 minutes (p < 0.0001); time to target/dock the retractor by 8 minutes (p < 0.0001); psoas retraction time by 6 minutes (p=0.0007). All PTP cases used saphenous SSEP monitoring; alerts were identified in 21% of cases, prompting interventions including adjusting positioning, closing the retractor, and/or finishing expeditiously. Other intra-op challenges included inadvertent ALL release in 2 (1.1%) of the ProneLat group, 4 (1.6%) of the PTP group (p>0.05). Blood loss and length of stay were similar between groups (p>0.05).

Conclusion : The comparison of pre- and post-proceduralization cohorts quantifies the efficiencies gained by the introduction of a procedure-specific systems that have measurably streamlined patient positioning, targeting, exposure, and interbody time requirements, while enabling single-position circumferential fusions. “PTP” has advantages over “prone lateral” procedures performed using systems designed for lateral decubitus LIF.

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