Prevalence of Lumbosacral Transitional Vertebral Anomalies Among Healthy Volunteers and Patients with Hip Pathology: Association with Spinopelvic Characteristics

Sagittal balance analysis and treatment rationale for young patients with symptomatic lumbosacral transitional vertebrae

Lumbosacral transitional vertebrae (LSTV) are a common anomaly in 7-36% of the population. LSTV can contribute to mechanical low back pain and increase the risk of early degeneration in cranial segments due to hypermobility and stress. This study analyzed sagittal balance in young symptomatic LSTV patients and tried to identify compensatory mechanisms that may explain early degeneration. Nineteen symptomatic and skeletally mature subjects with LSTV were retrospectively identified. Imaging included standing biplanar spine radiographs and supine lumbar MRI. Sagittal balance parameters were measured, and LSTV were classified using the Castellvi classification. Vertical mid-vertebral angle differences were calculated using MRI and lateral radiographs. The cohort included 17 females and 2 males (mean age 16 ± 3 years). Mean pelvic incidence was 67°±8°. L1-S1 lordosis averaged 61°±10°, L4-S1 lordosis was 10° lower than expected, and L4-L5 lordosis was higher than literature values. Thirteen patients had L4-L5 discopathy, with nine showing additional abnormalities such as interspinous ligament edema or posterior facet hypertrophy. In our study, LSTV was associated with L5-S1 disc hypoplasia and altered lumbar lordosis, leading to compensatory L4-L5 hyperextension. These findings suggest early degeneration may result from abnormal lordosis distribution. Treatment should aim to optimize lordosis distribution to reduce stress on adjacent segments.

The influence of lumbo-sacral transitional vertebrae in developmental dysplasia of the hip: a matched pair analysis

Lumbo-sacral transitional vertebrae (LSTV) are the most common congenital alteration of the lumbo-sacral junction and known to significantly influence pelvic anatomy. However, the influence of LSTV on dysplasia of the hip (DDH) and the surgical treatment by periacetabular osteotomy (PAO) remains unknown. We retrospectively examined standardized standing anterior-posterior pelvic radiographs of 170 patients in 185 PAO procedures. Radiographs were examined for LSTV, lateral-central-edge-angle (LCEA), Tönnis-angle (TA), femoral-head-extrusion index (FHEI), and anterior-wall-index (AWI) and posterior-wall-index (PWI). Patients with LSTV were compared to an age- and sex-matched control group. Patient-reported outcome measurements (PROMs) were evaluated pre- and in the mean 63.0 months (range 47-81 months) postoperatively. 43 patients (25.3%) had LSTV. Patients with LSTV had significantly greater PWI (p = 0.025) compared to the matched control group. No significant differences were seen in AWI (p = 0.374), LCEA (p = 0.664), TA (p = 0.667), and FHEI (p = 0.886). Between the two groups, no significant differences were detected in pre- or postoperative PROMs. Due to the increased dorsal femoral head coverage in patients with LSTV and DDH compared to patients with sole DDH, a more pronounced ventral tilting might be performed in those patients with prominent posterior wall sign to avoid anterior undercoverage, which is a significant predictor for premature conversion to hip arthroplasty after PAO. However, anterior overcoverage or acetabular retroversion must be avoided due to the risk of femoroacetabular impingement. Patients with LSTV reported similar functional outcomes and activity after PAO as the control group. Therefore, even for patients with concomitant LSTV, which are frequent with one-fourth in our cohort, PAO is an efficient treatment option to improve clinical symptoms caused by DDH.