Fatty infiltration in the multifidus predicts screw-loosening following short-segment decompression and fusion: proof of why we should protect and rehabilitate the paraspinal muscles
Murat Şakir Ekşi̇, Arda Topçu, Fatma Topaloğlu, Nursena Tanriverdi, Sidar Cenk Yeşilyurt, Umut Can Duymaz, Furkan Karakaş, Jülide Hazneci, Arif Topal, Ali Börekci, Tayfun Hakan, Erhan Çelikoğlu, Emel Ece Özcan-Ekşi̇
Abstract
PURPOSE: Screw-loosening is a common instrumentation-related complication following fusion. Patients who present with pain and neurological symptoms due to screw-loosening require revision. It has been reported that fat-infiltrated and/or atrophied paraspinal muscles were associated with low back pain, disability, radiculopathy, and instrumentation-related failures. However, there is limited and conflicting knowledge regarding the association of paraspinal muscles with screw-loosening. In the present study, we aimed to identify whether fatty infiltration in the paraspinal muscles was associated with screw-loosening. METHODS: A retrospective analysis of the clinical and radiological data of the patients who underwent short-segment decompression and fusion for lumbar spinal stenosis (LSS) at a tertiary spine clinic between 2013 and 2023. Goutallier's classification system was used for grading fatty infiltration in the paraspinal muscles. RESULTS: Patients with screw-loosening had fattier multifidus at the upper lumbar spine (particularly L2-L3, cephalad to the upper instrumented level of L3-L4) compared to those without screw-loosening. In univariate analysis fatty multifidus at L2-L3 level, elder age, and male sex had ORs of 1.509 (p = 0.008), 1.116 (p = 0.001) and 4.702 (p = 0.004), respectively. In multivariate analysis fatty multifidus at L2-L3 level, elder age and male sex had ORs 1.428 (p = 0.043), 1.109 (p = 0.003), and 5.911 (p = 0.004), respectively. CONCLUSION: Fatty infiltration in the multifidus muscle (particularly in the one at the cranial end of the fusion mass) is predictive for screw-loosening following short-segment lumbar decompression and fusion for LSS. Preserving multifidus in subjects is essential to prevent future long-term complications of spine surgery.