title: Expandable Polyaryl-Ether-Ether-Ketone Spacers for Interbody Distraction in the Lumbar Spine.
abstract: Study Design Retrospective case series. Objective StaXx XD (Spine Wave, Inc., Shelton, CT, United States) is an expandable polyaryl-ether-ether-ketone (PEEK) wafer implant utilized in the treatment of lumbar degenerative disease. PEEK implants have been successfully used as interbody devices. Few studies have focused on expandable PEEK devices. The aim of the current study is to determine the radiographic and clinical outcome of expandable PEEK cages utilized for transforaminal lumbar interbody fusion in patients with lumbar degenerative diseases. Methods Forty-nine patients who underwent lumbar interbody fusion with implantation of expandable PEEK cages and posterior instrumentation were included. The clinical outcome was evaluated using the visual analog scale (VAS) and the Oswestry Disability Index (ODI). Radiographic parameters including disk height, foraminal height, listhesis, local disk angle of the index level/levels, regional lumbar lordosis, and graft subsidence were measured preoperatively, postoperatively, and at latest follow-up. Results At an average follow-up of 19.3 months, the minimum clinically important difference for the ODI and VAS back, buttock, and leg were achieved in 64, 52, 58, and 52% of the patients, respectively. There was statistically significant improvement in VAS back (6.42 versus 3.11, p < 0.001), VAS buttock (4.66 versus 1.97, p = 0.002), VAS leg (4.55 versus 1.96, p < 0.001), and ODI (21.7 versus 12.1, p < 0.001) scores. There was a significant increase in the average disk height (6.49 versus 8.18 mm, p = 0.037) and foraminal height (15.6 versus 18.53 mm, p = 0.0001), and a significant reduction in the listhesis (5.13 versus 3.15 mm, p = 0.005). The subsidence of 0.66 mm (7.4%) observed at the latest follow-up was not significant (p = 0.35). Conclusions Midterm results indicate that expandable PEEK spacers can effectively and durably restore disk and foraminal height and improve the outcome without significant subsidence.
authors.affiliation: Weill Cornell Brain and Spine Center, Department of Neurological Surgery, Weill Cornell Medical College, New York-Presbyterian Hospital, New York, New York, United States.
authors.forename: Marjan
authors.initials: M
authors.lastname: Alimi
authors.affiliation: Weill Cornell Brain and Spine Center, Department of Neurological Surgery, Weill Cornell Medical College, New York-Presbyterian Hospital, New York, New York, United States.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Shin
authors.affiliation: Weill Cornell Brain and Spine Center, Department of Neurological Surgery, Weill Cornell Medical College, New York-Presbyterian Hospital, New York, New York, United States.
authors.forename: Michael
authors.initials: M
authors.lastname: Macielak
authors.affiliation: Weill Cornell Brain and Spine Center, Department of Neurological Surgery, Weill Cornell Medical College, New York-Presbyterian Hospital, New York, New York, United States.
authors.forename: Christoph P
authors.initials: CP
authors.lastname: Hofstetter
authors.affiliation: Weill Cornell Brain and Spine Center, Department of Neurological Surgery, Weill Cornell Medical College, New York-Presbyterian Hospital, New York, New York, United States.
authors.forename: Innocent
authors.initials: I
authors.lastname: Njoku
authors.affiliation: Department of Neuroradiology, Weill Cornell Medical College, New York-Presbyterian Hospital, New York, New York, United States.
authors.forename: Apostolos J
authors.initials: AJ
authors.lastname: Tsiouris
authors.affiliation: Weill Cornell Brain and Spine Center, Department of Neurological Surgery, Weill Cornell Medical College, New York-Presbyterian Hospital, New York, New York, United States.
authors.forename: Eric
authors.initials: E
authors.lastname: Elowitz
authors.affiliation: Weill Cornell Brain and Spine Center, Department of Neurological Surgery, Weill Cornell Medical College, New York-Presbyterian Hospital, New York, New York, United States.
authors.forename: Roger
authors.initials: R
authors.lastname: Härtl
keywords: Oswestry Disability Index; disc height; expandable PEEK cage; graft subsidence; interbody fusion; lumbar lordosis; lumbar spine; visual analog scale