118 - Incidence of Major Complications in Lateral Lumbar Interbody Fusion (LLIF) Performed via the Prone Transpsoas (PTP) Technique: A Survey of the Complete Early Experience

Introduction. A modification of the LLIF approach wherein lateral transpsoas access is achieved with the patient in the prone position was first presented in 2019 and was launched as a proceduralized technique known as PTP in 2020. Early reports focused on feasibility, perioperative clinical outcomes and efficiencies, and immediate postoperative alignment. Perioperative complications were reported as occurred in these small studies and were consistent with reports of similar complications in the historical LLIF literature. However, the novelty of prone positioning has raised question about the potential for different rates of known but uncommon lateral-approach complications such as visceral, vascular, and neurologic injury. The current study sought to identify the incidence of select major complications from the early PTP experience to-date.

Methods. A survey was created to query whether any patient in a surgeon’s PTP experience had suffered a major vascular (great vessel), visceral (bowel/kidney), or permanent (>6 mo) neurologic injury - major complications that have a high probability of recall. The survey was sent to all US surgeons who performed PTP from its launch in June 2020 to July 1, 2022, as identified through a commercial operational database. Through the same database, the number of procedures performed in that timeframe by each surgeon was confirmed. No surgeons were excluded from receiving the survey based on case volumes (any surgeon having completed at least a single PTP procedure was included), and the case data represented each surgeon’s entire consecutive PTP series. Multiple reminders were issued to solicit survey responses. If a positive response was received, the respondent was sent a follow-up survey to query the details of that case.

Results. A total of 243 surgeons were identified as having received the survey (after some attrition due to email blocking/bouncing). Responses were received from 131, a response rate of 54% of surgeons, and making up most of the total procedures known to have been performed. Among the 2,717 procedures completed by respondents, there were 2 vascular injuries (0.07%; CI: 0.01-0.27%), 4 bowel injuries (0.15%; CI: 0.04-0.38%), and 8 permanent neurological injuries (0.29%; CI: 0.13-0.58%). Details of each incident are pending responses to the follow-up survey.

Conclusions. The early PTP experience does not demonstrate a significantly higher rate of major vascular, visceral, or permanent neurologic injury than what has been reported in the literature for lateral decubitus LLIF. PTP is a safe procedure; the risk of any major complication is under 1%.