Intraoperative navigation-guided resection of anomalous transverse processes in patients with Bertolotti's syndrome

Risks Associated with Surgical Management of Lumbosacral Transitional Vertebrae: Systematic Review of Surgical Considerations and Illustrative Case

BACKGROUND

Lumbosacral transitional vertebrae (LSTV) are congenital anomalies of the L5-S1 segments characterized by either sacralization of the most caudal lumbar vertebra or lumbarization of the most cephalad sacral vertebra. This variation in anatomy exposes patients to additional surgical risks.

METHODS

In order to shed light on surgical considerations reported for lumbar spine cases involving LSTV as described in the extant literature, we performed a systematic review in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. We also present a case example in which wrong level surgery was avoided due to anatomical understanding of LSTV.

RESULTS

A 48-year-old female presented with severe back pain after sustaining a fall from ten feet. The patient exhibited full motor function in all extremities but had begun to experience urinary retention. On initial imaging read, the patient was suspected to have an L1 burst fracture. A review of the imaging demonstrated a transitional vertebra. Therefore, based on the last rib corresponding to T12, the fractured level was L2. This case illustrates the risk LSTV carries for wrong site surgery; appropriate levels were then decompressed and instrumented. On systematic review of the literature according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines, a three database literature search identified 39 studies describing 885 patients with LSTV and relevant surgical considerations. The primary indications for surgery were for disc herniation (37%), Bertolotti's syndrome (35%), and spinal stenosis (25%). This cohort displayed a mean follow-up time of 23 months. Reherniation occurred in 12 patients (5.5%). Medical management through steroid injection was 24, 72% (n = 80) for the sample. Wrong level surgery occurred in 1.4% (n = 12) of patients.

CONCLUSIONS

LSTV represents a constellation of changes in anatomy beyond just a sacralized or lumbarized vertebra. These anatomical differences expose the patient to additional surgical risks. This case and review of the literature highlight avoidable complications and in particular wrong level surgery.

Techniques for restoring optimal spinal biomechanics to alleviate symptoms in Bertolotti syndrome: illustrative case

BACKGROUND

Lumbosacral transitional vertebrae (LSTVs) are congenital anomalies that occur in the spinal segments of L5-S1. These vertebrae result from sacralization of the lowermost lumbar segment or lumbarization of the uppermost sacral segment. When the lowest lumbar vertebra fuses or forms a false joint with the sacrum (pseudoarticulation), it can cause pain and manifest clinically as Bertolotti syndrome.

OBSERVATIONS

A 36-year-old female presented with severe right-sided low-back pain. Computed tomography was unremarkable except for a right-sided Castellvi type IIA LSTV. The pain proved refractory to physical therapy and lumbar epidural spinal injections, but targeted steroid and bupivacaine injection of the pseudoarticulation led to 2 weeks of complete pain relief. She subsequently underwent minimally invasive resection of the pseudoarticulation, with immediate improvement in her low-back pain. The patient continued to be pain free at the 3-year follow-up.

LESSONS

LSTVs alter the biomechanics of the lumbosacral spine, which can lead to medically refractory mechanical pain requiring surgical intervention. Select patients with Bertolotti syndrome can benefit from operative management, including resection, fusion, or decompression of the pathologic joint.

Operative Treatment of Bertolotti Syndrome: Resection Versus Fusion

OBJECTIVE

To compare the outcomes of joint resection versus fusion in patients who undergo operative treatment for Bertolotti syndrome.

METHODS

A chart review identified patients with Bertolotti syndrome who underwent operative treatment, consisting of either Bertolotti joint decompression/resection or fusion across the abnormal transitional lumbosacral vertebrae. Patients with other symptomatic operative spinal disease were excluded.

RESULTS

Twenty-seven patients (9 men, 18 women) were identified for inclusion in the study with an average age of 40 ± 16 years, body mass index of 27 ± 5, and follow-up of 39 ± 48 months. Most patients presented with back pain (74%) or leg pain (48%) for an average duration of 61 ± 54 months. Nineteen (70%) presented with a Castellvi subtype 2a Bertolotti joint with computed tomography as the most common method for radiographic diagnosis (56%). When comparing long-term pain improvement (>12 months) after fusion (n = 9) versus joint resection (n = 18), more fusion patients reported improvement in their pain (78%) compared to joint resection (28%, P = 0.037). There was not a statistically significant difference in the short-term pain improvement (<6 months) between the fusion (100%) and resection (78%) patients (P = 0.27). There was no statistically significant difference between the two groups in terms of age, sex, body mass index, presenting symptoms, symptom duration, Bertolotti injection response, follow up, Castellvi subtype, and complications.

CONCLUSIONS

Patients with Bertolotti syndrome who underwent surgical fusion across the transitional lumbosacral vertebrae had a higher rate of long-term pain improvement compared to patients who had resection of the abnormal pseudoarticulation.

Pediatric Back Pain Associated with Bertolotti Syndrome: A Report of 3 Cases with Varying Treatment Strategies

CASE

Three pediatric patients with back pain associated with Bertolotti syndrome are presented. After failing conservative management, 1 patient underwent mega-apophysis resection, another underwent resection with decompression, and the final underwent posterior fusion. All patients had complete resolution of back pain and returned to full activity at final follow-up.

CONCLUSION

Lumbosacral transitional vertebrae are congenital anomalies spanning a spectrum from partial/complete L5 sacralization to partial/complete S1 lumbarization with varying clinical presentations. Identification of variable anatomy and symptoms guides surgical management. We present 3 cases with differing surgical techniques including pseudoarticulation resection, arthrodesis of the involved levels, and neuroforaminal decompression.

The effectiveness of preoperative assessment using a patient-specific three-dimensional pseudoarticulation model for minimally invasive posterior resection in a patient with Bertolotti's syndrome: a case report

Background

Bertolotti’s syndrome is widely known to cause low back pain in young patients and must be considered as a differential diagnosis. Its treatment such as conservative therapy or surgery remains controversial. Surgical procedure is recommended for intractable low back pain. The three-dimensional (3D) lumbosacral transitional vertebrae anatomy should be completely understood for a successful surgery. Using an intraoperative 3D navigation and preoperative preliminary surgical planning with a patient-specific 3D plaster model contribute for safe surgery and good outcome.

Case presentation

A case of a 22-year-old Japanese male patient with intractable left low back pain due to lumbosacral transitional vertebrae with Bertolotti’s syndrome. The symptom resisted the conservative treatment, and anesthetic injection at pseudoarticulation only provided a short-term pain relief. Posterior resection using intraoperative three-dimensional (3D) navigation has been performed through microendoscopic view. Pseudoarticulation was totally and successfully resected in a safe manner.

Conclusions

Preoperative surgical planning and rehearsal using a patient-specific 3D plaster model was greatly useful and effective for surgeons in performing accurate and safe pseudoarticulation resection.

Development of a novel in vitro cadaveric model for analysis of biomechanics and surgical treatment of Bertolotti syndrome

BACKGROUND CONTEXT

Bertolotti syndrome (BS) is caused by pseudoarticulation between an aberrant L5 transverse process and the sacral ala, termed a lumbosacral transitional vertebra (LSTV). BS is thought to cause low back pain and is treated with resection or fusion, both of which have shown success. Acquiring cadavers with BS is challenging. Thus, we combined 3D printing, based on BS patient CT scans, with normal cadaveric spines to create a BS model. We then performed biomechanical testing to determine altered kinematics from LSTV with surgical interventions. Force sensing within the pseudojoint modeled nociception for different trajectories of motion and surgical conditions.

PURPOSE

This study examines alterations in spinal biomechanics with LSTVs and with various surgical treatments for BS in order to learn more about pain and degeneration in this condition, in order to help optimize surgical decision-making. In addition, this study evaluates BS histology in order to better understand the pathology and to help define pain generators-if, indeed, they actually exist.

STUDY DESIGN/SETTING

Model Development: A retrospective patient review of 25 patients was performed to determine the imaging criteria that defines the classical BS patient. Surgical tissue was extracted from four BS patients for 3D-printing material selection. Biomechanical Analysis. This was a prospective cadaveric biomechanical study of seven spines evaluating spinal motions, and loads, over various surgical conditions (intact, LSTV, and LSTV with various fusions). Additionally, forces at the LSTV joint were measured for the LSTV and LSTV with fusion condition. Histological Analysis: Histologic analysis was performed prospectively on the four surgical specimens from patients undergoing pseudoarthrectomy for BS at our institution to learn more about potential pain generators.

PATIENT SAMPLE

The cadaveric portion of the study involved seven cadaveric spines. Four patients were prospectively recruited to have their surgical specimens assessed histologically and biomechanically for this study. Patients under the age of 18 were excluded.

OUTCOME MEASURES

Physiological measures recorded in this study were broken down into histologic analysis, tissue biomechanical analysis, and joint biomechanical analysis. Histologic analysis included pathologist interpretation of Hematoxylin and Eosin staining, as well as S-100 staining. Tissue biomechanical analysis included stiffness measurements. Joint biomechanical analysis included range of motion, resultant torques, relative axis angles, and LSTV joint forces.

METHODS

This study received funding from the American Academy of Neurology Medical Student Research Scholarship. Three authors hold intellectual property rights in the simVITRO robotic testing system. No other authors had relevant conflicts of interest for this study. CT images were segmented for a representative BS patient and cadaver spines. Customized cutting and drilling guides for LSTV attachment were created for individual cadavers. 3D-printed bone and cartilage structural properties were based on surgical specimen stiffness, and specimens underwent histologic analysis via Hematoxylin and Eosin, as well as S-100 staining. Joint biomechanical testing was performed on the robotic testing system for seven specimens. Force sensors detected forces in the LSTV joint. Kruskal-Wallis tests and Dunnett's tests were used for statistical analysis with significance bounded to p<.05.

RESULTS

LSTV significantly reduces motion at the L5-S1 level, particularly in lateral bending and axial rotation. Meanwhile, the LSTV increases adjacent segment motion significantly at the L2-L3 level, whereas other levels have nonsignificant trends toward increased motion with LSTV alone. Fusion involving L4-S1 (L4-L5 and L5-S1) to treat adjacent level degeneration associated with an LSTV is associated with a significant increase in adjacent segment motion at all levels other than L5-S1 compared to LSTV alone. Fusion of L5-S1 alone with LSTV significantly increases L3-L4 adjacent segment motion compared to LSTV alone. Last, ipsilateral lateral bending with or without ipsilateral axial rotation produces the greatest force on the LSTV, and these forces are significantly reduced with L5-S1 fusion.

CONCLUSIONS

BS significantly decreases L5-S1 mobility, and increases some adjacent segment motion, potentially causing patient activity restriction and discomfort. Ipsilateral lateral bending with or without ipsilateral axial rotation may cause the greatest discomfort overall in these patients, and fusion of the L5-S1 or L4-S1 levels may reduce pain associated with these motions. However, due to increased adjacent segment motion with fusions compared to LSTV alone, resection of the joint may be the better treatment option if the superior levels are not unstable preoperatively.

CLINICAL SIGNIFICANCE

This study's results indicate that patients with BS have significantly altered spinal biomechanics and may develop pain due to increased loading forces at the LSTV joint with ipsilateral lateral bending and axial rotation. In addition, increased motion at superior levels when an LSTV is present may lead to degeneration over time. Based upon results of LSTV joint force testing, these patients' pain may be effectively treated surgically with LSTV resection or fusion involving the LSTV level if conservative management fails. Further studies are being pursued to evaluate the relationship between in vivo motion of BS patients, spinal and LSTV positioning, and pain generation to gain a better understanding of the exact source of pain in these patients. The methodologies utilized in this study can be extrapolated to recreate other spinal conditions that are poorly understood, and for which few native cadaveric specimens exist.

Understanding quality of life and treatment history of patients with Bertolotti syndrome compared with lumbosacral radiculopathy

OBJECTIVE

Bertolotti syndrome is a rare spinal condition that causes low-back pain due to a lumbosacral transitional vertebra (LSTV), which is a pseudoarticulation between the fifth lumbar transverse process and the sacral ala. Bertolotti syndrome patients are rarely studied, particularly with regard to their quality of life. This study aimed to examine the quality of life and prior treatments in patients with Bertolotti syndrome at first presentation to the authors' center in comparison with those with lumbosacral radiculopathy.

METHODS

This study was a retrospective cohort analysis of patients with Bertolotti syndrome and lumbosacral radiculopathy due to disc herniation seen at the authors' institution's spine center from 2005 through 2018. Diagnoses were confirmed with provider notes and imaging. Variables collected included demographics, diagnostic history, prior treatment, patient-reported quality of life metrics, and whether or not they underwent surgery at the authors' institution. Propensity score matching by age and sex was used to match lumbosacral radiculopathy patients to Bertolotti syndrome patients. Group comparisons were made using t-tests, Fisher's exact test, Mann-Whitney U-tests, Cox proportional hazards models, and linear regression models where variables found to be different at the univariate level were included as covariates.

RESULTS

The final cohort included 22 patients with Bertolotti syndrome who had patient-reported outcomes data available and 46 propensity score-matched patients who had confirmed radiculopathy due to disc herniation. The authors found that Bertolotti syndrome patients had significantly more prior epidural steroid injections (ESIs) and a longer time from symptom onset to their first visit. Univariate analysis showed that Bertolotti syndrome patients had significantly worse Patient-Reported Outcomes Measurement Information System (PROMIS) mental health T-scores. Adjustment for prior ESIs and time from symptom onset revealed that Bertolotti syndrome patients also had significantly worse PROMIS physical health T-scores. Time to surgery and other quality of life metrics did not differ between groups.

CONCLUSIONS

Patients with Bertolotti syndrome undergo significantly longer workup and more ESIs and have worse physical and mental health scores than age- and sex-matched patients with lumbosacral radiculopathy. However, both groups of patients had mild depression and clinically meaningful reduction in their quality of life according to all instruments. This study shows that Bertolotti syndrome patients have a condition that affects them potentially more significantly than those with lumbosacral radiculopathy, and increased attention should be paid to these patients to improve their workup, diagnosis, and treatment.

Surgical management of Bertolotti's syndrome in two adolescents and literature review

Background:

Bertolotti’s syndrome is defined by back pain and/or radicular symptoms attributed to a congenital lumbosacral transitional vertebra (LSTV). There are few studies that discuss the surgical management of Bertolotti’s syndrome. Here, we report long-term outcomes after resecting a pseudoarthrosis between the sacrum and L5 in two teenage patients, along with a review of literature.

Case Descriptions:

Surgical resection of a lumbosacral bridging articulation (LSTV type IIa) was performed in two patients, 15 and 16 years of age who presented with intractable back pain. The adequacy of surgery was confirmed with postoperative studies. In both patients, pain and functional status improved within 6 weeks and have remained improved at last follow-up.

Conclusion:

Surgical removal of a pathologic L5 transverse process fused to the sacral ala in two young patients with Bertolotti’s syndrome improved postoperative pain and increased overall function. Given the progressive nature of Bertolotti’s syndrome, surgical intervention in young patients should be considered to mitigate years of chronic pain and attendant morbidity.

Bertolotti's syndrome: an underdiagnosed cause for lower back pain

Bertolotti's syndrome refers to the presence of pain associated to the anatomical variant of sacralization of the last lumbar vertebra. It is often a factor that is not addressed in the evaluation and treatment of lower back pain. The presence of a lumbosacral transitional vertebra is a common finding among general population with a prevalence that ranges between 4 and 30%, however, this finding is rarely associated to the cause of lower back pain and thus, the prevalence of Bertolotti's syndrome in general population is unknown doe to underdiagnosis. The sacralization of the fifth lumbar vertebra has been related to changes in the anatomy and biomechanics of the spine with no general agreement to its clinical significance, however Bertolotti's syndrome should be considered as a differential diagnosis for lower back pain, therefore, its pathophysiology, epidemiology and treatment must be a topic of general knowledge to physicians that often treat this condition.