Vitamin D levels and pain outcomes in adolescent idiopathic scoliosis patients undergoing spine fusion.

Purpose: Prior research has indicated adolescent idiopathic scoliosis (AIS) patients have lower bone mineral density and lower vitamin D levels than healthy peers. Vitamin D deficiency has been associated with higher levels of pain. This study investigated whether vitamin D-deficient AIS patients had higher pain before or immediately after posterior spine fusion (PSF) surgery.

Methods: 25-Hydroxy vitamin D levels were tested in all AIS patients at their pre-operative appointment. Patients were grouped by serum 25-hydroxy vitamin D level: deficient, < 20 ng/mL; insufficient, 20-29 ng/mL; sufficient, ≥ 30 ng/mL. Primary outcomes included pre-operative Scoliosis Research Society Health-Related Quality of Life (SRS-30) and numeric rating scale (NRS) scores (0-10) up to 72 h post-operatively, and analyzed using ANOVA and linear mixed modeling, respectively. 176 patients undergoing PSF were included. Intra-operative characteristics by vitamin D status were also assessed. The cohort was 82% female and an average of 15.2 years (range 10.6-25.3 years) at fusion. Average major curve was 60 (range 40-104) degrees pre-operatively.

Results: Forty-five (26%) patients were deficient in vitamin D, 75 (43%) were insufficient, and 56 (32%) were sufficient. Patients with vitamin D deficiency had lower average household income by zip code (p < 0.01) and higher secondhand smoke exposure (p < 0.001). There were no differences in pre-operative SRS-30 score, pre- and post-operative major curve angles, or estimated blood loss across vitamin D groups. Trajectories of NRS indicated no differences in pain during the first 72 h after surgery.

Conclusion: Vitamin D deficiency in this population is associated with potential markers of lower socioeconomic status; however, it does not influence AIS PSF patients' experience of pain before or immediately after spine fusion surgery.

Level Of Evidence: II.