Morselized corticocancellous bone as primary graft for posterior lumbar fusion: a systematic review and meta-analysis

Synthetic cages are commonly used in posterior and transforaminal lumbar interbody fusion procedures. Using morselized corticocancellous bone from spinous processes and laminae has been suggested as an alternative, especially in low-resource settings where access to synthetic cages is limited. The aim of this study was to compare radiographic and functional outcomes of synthetic cages with those of morselized local autograft.

MEDLINE and EMBASE database search strategies were created by a medical librarian following the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. Screening and data extraction were performed in duplicate by two authors using predefined criteria. A meta-analysis of fusion rates, functional scores including Visual Analogue Scale (VAS) and Oswestry Disability Index (ODI), operative time, and blood loss was performed on studies that met the selection criteria. Qualitative appraisal of post-operative disc heights and complication profile was performed. Methodological index for non-randomized studies (MINORS) criteria were used to ascertain the quality of included studies.

7 cohort studies were included in the finaly analysis, with 284 patients in the morselized local graft group and 276 patients in the synthetic cage group. There was no significant difference in fusion rates between the two cohorts at final follow-up (minimum 1 year; P = 0.21, I² = 30%). Likewise, no difference was seen in any of the secondary outcomes included in this meta-anlysis. Disc height at final follow-up was similar between the two cohorts in all included studies.

Usage of morselized corticocancellous autograft to achieve interbody fusion can be a suitable alternative to synthetic cages, especially in low-resource settings where the cost of synthetic cages can be prohibitive.