Preliminary Safety and Outcomes of Paraspinous Tension Band FDA Trial for Degenerative Spondylolisthesis
Presented at SMISS Annual Forum 2019
By Louis Fielding
Disclosures: Louis Fielding D; Empirical Spine. E; Empirical Spine. F; Empirical Spine.
Degenerative spondylolisthesis (DS) with lumbar spinal stenosis (LSS) is commonly treated with decompression and fusion. The LimiFlex Paraspinous Tension Band (PTB; Empirical Spine, San Carlos, CA) is a new potential option for patients with DS and LSS, designed to provide sagittal plane stabilization after decompression.
The purpose of this study was to assess the operative safety and short-term outcomes of PTB compared to transforaminal lumbar interbody fusion (TLIF) for patients with DS with LSS.
Patients undergoing decompression for single-level Grade 1 DS with LSS were enrolled in the open-label, multicenter, FDA-IDE study with 2 arms: decompression with PTB or TLIF. Patients’ perioperative and patient-reported clinical outcomes were recorded at baseline, and postoperatively at 6 weeks, 3 months, and 6 months. All patients who reached a minimum of 6-months follow-up were included in this interim analysis. Summary statistics are reported, as well as paired t-tests to assess within-group changes in pain and disability scores.
One hundred patients (63 PTB and 37 TLIF) reached 6-months follow-up. Characteristics of PTB and TLIF groups, respectively were: age 64.5±8.2 and 63.9±7.4 yrs; BMI 28.4±4.9 and 29.3±5.7; current smokers 2% and 3% (all NS). Perioperative outcomes of PTB and TLIF groups, respectively, were: operative time 113±29 and 174±57 minutes; EBL 44±29 and 258±167 mL; LOS 0.6±1.5 and 3.4±1.7days. A statistically significant reduction from baseline to 6 months for mean VAS leg (80.5±9.7 to 19.9±23.0), VAS back (65.6±23.5 to 15.8±21.6) and ODI scores (53.1±12.4 to 13.2±14.1) was reported for PTB patients (all p<0.01), with 87% of patients achieving 20pt ODI improvement. A similar improvement was reported for TLIF patients for VAS leg (78.7±15.7 to 27.9±33.4), VAS back (71.7±18.4 to 22.9±26.8), and ODI (51.2±12.8 to 19.7±21.2) (all p<0.01), with 70% achieving 20pt ODI improvement. During the 6-month follow-up period, 1 PTB subject (1.6%) was revised to posterolateral fusion during the same hospital stay due to intraoperative spinous process fracture resulting in inability to place the PTB, and 2 (5.4%) TLIF subjects were revised to L3-S1 fusions due to symptom progression, including 1 instance of cage/screw migration.
These preliminary results suggest PTB stabilization after decompression for DS with LSS can be accomplished safely without a significant increase in perioperative complications. Short-term improvements in patient-reported outcomes for LimiFlex treated patients are comparable to fusion- treated patients. Further investigation will include quantitative comparison between propensity score-matched groups with long-term follow up to confirm these results.