Tag: Expandable spacer

Brain and Spine 5 (2025) 104322

This study developed and internally validated the Expandable TLIF Subsidence Index (ETSI) to predict risk of cage subsidence after TLIF surgery with expandable spacers. Key risk factors include high ASA score, non-degenerative indication, lower lumbar levels, small cage size, and posterior cage position.

• A risk score (Expandable TLIF Subsidence Index, ETSI) was developed to predict cage subsidence (CS) after transforaminal lumbar interbody fusion (TLIF) using expandable spacers.

• The study analyzed 388 patients (482 levels), finding a 31.7% CS rate at 3 months.

• Independent risk factors for CS included high ASA score, non-degenerative surgical indication, lower lumbar level, small cage size, and posterior cage position.

• The ETSI score ranges from -2 to 6; higher scores indicate higher CS risk (each point increases CS odds by about 2x).

• Modifiable risk factors (cage size and position) can reduce CS risk if addressed during surgery.

• Higher ETSI scores are also associated with increased risk of non-union/pseudarthrosis.

• The ETSI demonstrated moderate predictive performance (AUROC ≈ 0.68).

• The score may aid surgical planning and should be externally validated in future studies.

Brain and Spine 5 (2025) 104322

This study developed and validated the Expandable TLIF Subsidence Index (ETSI) to predict risk of cage subsidence after TLIF surgery with expandable spacers. Key risk factors include high ASA score, non-degenerative indications, lower lumbar level, small cage size, and posterior cage position. Some risk factors are modifiable.

• A risk score (ETSI) was developed to predict cage subsidence (CS) after TLIF surgery using expandable spacers.

• Independent risk factors for CS include high ASA score, non-degenerative surgical indication, lower lumbar level, small cage size, and posterior cage position.

• ETSI ranges from -2 to 6 points and shows a moderate ability to classify CS risk (AUROC ≈ 0.68).

• Modifiable risk factors (cage size and position) can reduce CS risk if optimized by the surgeon.

• Higher ETSI scores are associated with increased risk of non-union/pseudarthrosis at 3 and 12 months.

• Anterior placement of the cage lowers subsidence risk, while posterior placement increases it.

• The study included 388 patients with a 3-month CS rate of 31.7%.

• The ETSI is the first comprehensive scoring system for CS risk with expandable TLIF cages.