Natural History of Lumbosacral Transitional Vertebrae Diagnosis and Treatment: An Institutional Examination of an Underreported Finding

Introduction: Lumbosacral Transitional Vertebrae (LSTV) are congenital malformations consisting of inappropriate articulations between L5 vertebrae and the sacrum which can be asymptomatic, or may cause Bertolotti Syndrome, an underdiagnosed cause of lower back pain (LBP). This study explores the natural history of LSTV diagnosis and treatment in the largest sample of U.S. patients to date.

Methods: A retrospective chart review between 2014-2023 identified patients via a free-text search engine querying a Midwest tertiary care institution’s EMR for terms related to “LSTV” and “Bertolotti”. Patients were excluded if imaging lacked evidence of an abnormal fusion between L5 and sacrum/ilium. Demographic and clinical features - including physical exam findings, imaging results, and referral and intervention history - were analyzed with descriptive statistics and chi-squared analyses.

Results: Of 122 patients with LSTV, 88.5% presented with LBP consistent with Bertolotti Syndrome. 45.1% of these patients reported radiculopathy, and 54.1% had sacroiliac (SI) joint pain. Only 5.7% had lower extremity strength deficit. The most common imaging modality for diagnosis was X-Ray (44.3%), followed by MRI (18.9%) and CT (9.8%). 15 (12.3%) cases were diagnosed by clinician interpretation despite null findings on radiographic reports. No statistically significant association existed between Castellvi type or laterality and clinical presentation (P>.05). 46 patients (42.6%) were referred to Pain Medicine. Of these patients, 32 (69.6%) received steroid injections, with 75.0% reporting pain relief for a median duration of 6 weeks (IQR: 2-9). 12 patients (9.8%) underwent surgical intervention targeting their LSTV. 10 of these patients (83.3%) reported significant improvement in LBP within 6 months postoperatively.

Conclusion : Our findings highlight the need to bolster clinician awareness and diagnostic accuracy of LSTV. There is a significant under-referral of these patients to Pain Medicine, where targeted injections not only provide short-term relief, but also serve as diagnostic tools that facilitate timely referral for surgical intervention.