Neurosurgery Resident University of Arizona College of Medicine - Tucson Tucson, AZ, US
Disclosure(s):
Ryan P. Palsma, MD: No financial relationships to disclose
Introduction: Preoperative planning with patient-specific rods used in adult spinal deformity and adolescent idiopathic scoliosis allow for optimized spinopelvic correction in sagittal vertical axis (SVA) and pelvic incidence – lumbar lordosis mismatch (PI-LL). We describe, for the first time, the use of patient-specific rods to achieve and maintain planned spinopelvic parameters 1-year after minimally invasive lumbar fusion for adult lumbar degenerative pathologies.
Methods: A total of 15 patients underwent minimally invasive lumbar fusions using patient-specific rods planned from standing scoliosis x-rays. Preoperative, plan, and 1-year postoperative spinopelvic parameters (SVA and PI-LL mismatch) were compared. Each parameter was summarized using mean ± SD by pre-op, plan and 1-year post-op. Paired t test was performed to compare plan with 1-year post-op. Scatter and Bland-Altman plots were generated to visualize the relationship and agreement. Pearson correlation coefficient (rho) was derived to describe the correlation. Fisher’s z test was conducted to evaluate whether the correlation is significantly different from 0.
Results: In general, the correlation and agreement between planned and 1-year postoperative spinopelvic parameters were high, especially SVA (rho = 0.75, p-value=0.0053) and PI-LL mismatch (rho = 0.8, p-value=0.0004). There were 6 men and 10 women. Typical adult lumbar pathologies were treated with MI-TLIF and MI-OLIF. 1-level fusion (13) and 2-level fusions (3) were performed without complications. Surgical levels were L3-4 (1), L4-5 (16), and L5-S1 (2). Average length of stay was 0.2 days.
Conclusion : Until now, patient-specific rods have only been used in adult spinal deformity and adolescent idiopathic scoliosis. This is the first reported use of patient-specific rods to optimize spinopelvic parameters of sagittal balance in adult lumbar degenerative pathologies. The high correlation in sagittal balance (SVA and PI-LL mismatch) between preoperative, planned, and 1-year postoperative x-rays demonstrate that this can be successfully applied to adult lumbar degenerative pathologies.
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