Sacropelvic Parameters and L5 Spondylolysis: Computed Tomography Analysis

Abstract

This study aims to determine the association of sagittal sacropelvic parameters with L5 spondylolysis. Overview of Literature: The association of increased pelvic incidence (PI) and decreased sacral table angle (STA) with spondylolysis has been reported, but no study has simultaneously analyzed multiple sacropelvic variables to compare their association. Methods: In this study, computed tomography scans obtained to assess major trauma in patients aged >16 years were analyzed. Scans meeting one of the following criteria were excluded: abnormal anatomy, previous spine or hip/pelvis surgery, or spinal pathology, including deformity, infection, tumor, or trauma. sacral anatomic orientation (SAO), PI, pelvic thickness (PTH), femoro-sacral posterior angle (FSPA), STA, and sacral kyphosis (SK) were measured. Results: Overall, 202 scans were analyzed: 25 with L5 spondylolysis and 177 normal. Among the groups, a significant difference was observed in SAO (43.3° vs. 51.6°), PI (61.7° vs. 49.8°), STA (95.4° vs. 101.8°), and SK (31.0° vs. 23.7°). Based on the logistic regression analysis, only PI (odds ratio [OR], 1.074; 95% CI, 1.026-1.124) and STA (OR, 0.822; 95% CI, 0.734-0.920) remained significant predictors for the presence of spondylolysis. In the spondylolysis group, PI correlated significantly with PTH (r=−0.589), FSPA (r=0.880), and SK (r=0.576), whereas in the normal group, PI correlated significantly with FSPA (r=0.781) and SK (r=0.728). Conclusions: By simultaneously assessing multiple sacropelvic parameters, we associated increasing PI with L5 spondylolysis. Decreasing STA, which likely represents a chronic remodeling secondary to spondylolysis, was also associated with increased risk. Back pain in an adolescent or young adult with high PI or low STA should raise suspicion of a possible occult spondylolysis.

Comparison of L5 pedicle morphology in patients with and without L5 spondylolysis

“…This concept is supported in the current study-there was a significant moderate correlation between pedicle width and STA which suggests that as more remodeling takes place in the proximal sacrum that the L5 posterior elements also in turn remodel (Baker, 2021;Sugawara et al, 2020;Tallarico et al, 2015).…”

“…Although L5 pedicle morphology has been studied in those with established spondylolisthesis the L5 pedicle morphology in simply the presence of spondylolysis has not yet been well defined with limited findings reported (Bajwa et al, 2012). The presence of spondylolysis alone has been associated with changes in sacral morphology so one may anticipate that changes in the posterior elements of the vertebrae to also be present and this has implications for the operating surgeon (Baker, 2021; Sugawara et al, 2020; Tallarico et al, 2015).…”

Radiological Characteristics of Low-Grade Lytic Spondylolisthesis: Similarity to Dysplastic Spondylolisthesis

“…In such cases, active use of graft materials, such as bone morphogenic proteins, would be recommended. Finally, recent studies have shown that L5 spondylolysis is associated with increased pelvic incidence [ 27 ]. Therefore, whole spine scanography should be performed prior to surgery for lytic spondylolisthesis, and the appropriate lordosis and fusion level should be determined based on the pelvic parameters.…”

Cost-Utility Analysis of Sacroiliac Joint Fusion in High-Risk Patients Undergoing Multi-Level Lumbar Fusion to the Sacrum

“…11 Assuming a mean PI of 50° (standard deviation of 10°) in normal populations, 15.9% of patients have high PI (>60°). 6,[12][13][14] Assuming statistical independence, 6.5% of patients undergoing lumbar fusion are both obese and have high PI, whereas 57% of patients are either obese or have high PI. Hence, the applicable high-risk population likely ranges from 6.5% to 57% of MLF patients, which merits further research to more precisely define the true population at high risk.…”

“…The model population was obese adults (BMI of 30-39.9) with high PI (>60°) who are undergoing MLF with versus without SIJF. 6,[11][12][13][14] Diagnoses for the model population included spondylolisthesis; lumbosacral intervertebral disc disorder; adult degenerative scoliosis; post-laminectomy syndrome; and flat back syndrome. The model population excludes patients with morbid obesity (BMI 40+), heavy smoking, uncontrolled diabetes (A1C > 7.5%), low T-score (severe osteoporosis), congenital neuromuscular disease, prior pelvic or SIJ fixation, and grade IV spondylolisthesis.…”