Identifying the relationship between lumbar sacralization and adjacent ligamentous anatomy in patients with Bertolotti syndrome and healthy controls.

OBJECTIVE: Bertolotti syndrome is a diagnosis given to patients experiencing low-back pain due to a lumbosacral transitional vertebra (LSTV). LSTVs cause altered biomechanics at the lumbosacral junction, predisposing these patients to degenerative disease. It has been proposed that these patients have additional non-osseous variation such as ligamentous differences in the lumbar spine. The iliolumbar ligament, which attaches from the iliac crest to the transverse process of L4 and L5, plays a significant role in reducing lumbar motion in all six degrees of freedom; therefore, altered ligament anatomy can have a significant impact on stability. The purpose of this study was to examine the iliolumbar ligament complex in patients with Bertolotti syndrome and anatomically normal controls to determine if underdevelopment of the iliolumbar ligament complex is seen in Bertolotti syndrome. METHODS: This is a retrospective analysis of patients with Bertolotti syndrome and anatomically normal controls who received care at the authors' institution between 2010 and 2020. Axial thickness of the iliolumbar ligament at the L5 vertebral level was assessed via MRI. Results were compared between the defective and normal side within unilaterally affected (Castellvi types IIa and IIIa) Bertolotti syndrome patients, between defective sides in bilaterally affected Bertolotti syndrome patients (Castellvi types IIb, IIIb, and IV), and between the affected side in Bertolotti syndrome patients and the corresponding location in normal controls. RESULTS: A total of 173 patients were included in the study, 102 with Bertolotti syndrome and 71 controls. Among the Bertolotti patients, 49 had left LSTVs, 29 had right LSTVs, and 24 had bilateral LSTVs. For patients with unilateral defects, defective side ligaments were thinner than ligaments on the normal side (p < 0.05). For bilateral LSTVs, ligament thickness on each side was considered statistically equivalent (p < 0.05) and not significantly different from that in controls. CONCLUSIONS: Bertolotti syndrome correlates to significant underdevelopment of the iliolumbar ligament corresponding to the side of the LSTV as compared to the ligament on the contralateral side. In patients with bilateral LSTVs, no difference in the iliolumbar ligament compared to that in controls was seen. Developmental changes in the iliolumbar ligament may further exacerbate the altered lumbosacral biomechanics seen in patients with unilateral LSTV, whereas bilateral LSTVs may still allow normal development of the ligament complex. Further research should be done to examine the discrepancies seen in this study.

Quality-of-life and postoperative satisfaction following pseudoarthrectomy in patients with Bertolotti syndrome.

BACKGROUND CONTEXT: Bertolotti syndrome is a clinical diagnosis given to patients with back pain arising from a lumbosacral transitional vertebra (LSTV). A particular class of LSTV involves a pseudoarticulation between the fifth lumbar transverse process and the sacral ala, and surgical resection of the pseudoarticulation may be offered to patients failing conservative management. Bertolotti syndrome is still not well understood, particularly regarding how patients respond to surgical resection of the LSTV pseudoarticulation. PURPOSE: To examine change in quality-of-life (QOL) and patient satisfaction following surgical resection of the LSTV pseudoarticulation in patients with Bertolotti syndrome. DESIGN: Ambidirectional observational cohort study of patients seen at a single institution's tertiary spine center over a 10-year period. PATIENT SAMPLE: Cohort consisted of 31 patients with Bertolotti Syndrome who underwent surgical resection of the pseudoarticulation. OUTCOME MEASURES: Preoperative and postoperative Patient-Reported Outcomes Measurement Information System Global Health (PROMIS-GH) Mental and Physical Health T-scores, and a single-item postoperative satisfaction questionnaire. METHODS: Patients were identified through diagnostic and procedural codes. Immediate preoperative PROMIS-GH scores available in the chart were gathered retrospectively, and postoperative PROMIS-GH and satisfaction scores were gathered prospectively through a mail-in survey. RESULTS: Mean (SD) improvement of PROMIS-GH Physical Health T-score was 8.7 (10.5) (p<.001). Mean (SD) improvement of PROMIS-GH Mental Health T-scores was 5.9 (9.2) (p=.001). When stratifying PROMIS-GH T-scores by response to the patient satisfaction survey, there were significant group differences in mean change for Physical Health T-scores (p<.001), and Mental Health T-score (p=.009). Patients who stated, "The treatment met my expectations" had much greater mean improvement in the PROMIS-GH T-scores. CONCLUSIONS: Patients undergoing a pseudoarticulation resection procedure may experience a significant improvement in quality-of-life as measured by PROMIS-GH Mental and Physical Health.

Assessment of L5-S1 anterior lumbar interbody fusion stability in the setting of lengthening posterior instrumentation constructs: a cadaveric biomechanical study.

OBJECTIVE: Excessive stress and motion at the L5-S1 level can lead to degenerative changes, especially in patients with posterior instrumentation suprajacent to L5. Attention has turned to utilization of L5-S1 anterior lumbar interbody fusion (ALIF) to stabilize the lumbosacral junction. However, questions remain regarding the effectiveness of stand-alone ALIF in the setting of prior posterior instrumented fusions terminating at L5. The purpose of this study was to assess the biomechanical stability of an L5-S1 ALIF with increasing lengths of posterior thoracolumbar constructs. METHODS: Seven human cadaveric spines (T9-sacrum) were instrumented with pedicle screws from T10 to L5 and mounted to a 6 degrees-of-freedom robot. Posterior fusion construct lengths (T10-L5, T12-L5, L2-5, and L4-5) were instrumented to each specimen, and torque-fusion level relationships were determined for each construct in flexion-extension, axial rotation, and lateral bending. A stand-alone L5-S1 ALIF was then instrumented, and L5-S1 motion was measured as increasing pure moments (2 to 12 Nm) were applied. Motion reduction was calculated by comparing L5-S1 motion across the ALIF and non-ALIF states. RESULTS: The average motion at L5-S1 in axial rotation, flexion-extension, and lateral bending was assessed for each fusion construct with and without ALIF. After adding ALIF to a posterior fusion, L5-S1 motion was significantly reduced relative to the non-ALIF state in all but one fused surgical condition (p < 0.05). Longer fusions with ALIF produced larger L5-S1 motions, and in some cases resulted in motions higher than native state motion. CONCLUSIONS: Posterior fusion constructs up to L4-5 could be appropriately stabilized by a stand-alone L5-S1 ALIF when using a nominal threshold of 80% reduction in native motion as a potential positive indicator of fusion. The results of this study allow conclusions to be drawn from a biomechanical standpoint; however, the clinical implications of these data are not well defined. These findings, when taken in appropriate clinical context, can be used to better guide clinicians seeking to treat L5-S1 pathology in patients with prior posterior thoracolumbar constructs.

Identifying treatment patterns in patients with Bertolotti syndrome: an elusive cause of chronic low back pain.

BACKGROUND CONTEXT: Bertolotti Syndrome is a diagnosis given to patients with lower back pain arising from a lumbosacral transitional vertebra (LSTV). These patients can experience symptomatology similar to common degenerative diseases of the spine, making Bertolotti Syndrome difficult to diagnose with clinical presentation alone. Castellvi classified the LSTV seen in this condition and specifically in types IIa and IIb, a "pseudoarticulation" is present between the fifth lumbar transverse process and the sacral ala, resulting in a semi-mobile joint with cartilaginous surfaces.Treatment outcomes for Bertolotti Syndrome are poorly understood but can involve diagnostic and therapeutic injections and ultimately surgical resection of the pseudoarticulation (pseudoarthrectomy) or fusion of surrounding segments. PURPOSE: To examine spine and regional injection patterns and clinical outcomes for patients with diagnosed and undiagnosed Bertolotti Syndrome. DESIGN: Retrospective observational cohort study of patients seen at a single institution's tertiary spine center over a 10-year period. PATIENT SAMPLE: Cohort consisted of 67 patients with an identified or unidentified LSTV who were provided injections or surgery for symptoms related to their chronic low back pain and radiculopathy. OUTCOME MEASURES: Self-reported clinical improvement following injections and pseudoarthrectomy. METHODS: Patient charts were reviewed. Identification of a type II LSTV was confirmed through provider notes and imaging. Variables collected included demographics, injection history and outcomes, and surgical history for those who underwent pseudoarthrectomy. RESULTS: A total of 22 out of 67 patients (33%) had an LSTV that was not identified by their provider. Diagnosed patients underwent fewer injections for their symptoms than those whose LSTV was never previously identified (p = 0.031). Only those diagnosed received an injection at the LSTV pseudoarticulation, which demonstrated significant symptomatic improvement at immediate follow up compared to all other injection types (p = 0.002). Patients who responded well to pseudoarticulation injections were offered a pseudoarthrectomy, which was more likely to result in symptom relief at most recent follow up than patients who underwent further injections without surgery (p < 0.001). CONCLUSIONS: Undiagnosed patients are subject to a higher quantity of injections at locations less likely to provide relief than pseudoarticulation injections. These patients in turn cannot be offered a pseudoarthrectomy which can result in significant relief compared to continued injections alone. Proper and timely identification of an LSTV dramatically alters the clinical course of these patients as they can only be offered treatment directed towards the LSTV once it is identified.