What is Transitional Vertebrae Of The Lumbosacral Junction? Bertolotti's Syndrome - A Rare Cause Of Back Pain

Understanding Bertolotti’s Syndrome: Transitional Vertebra at the Lumbosacral Junction

Bertolotti’s Syndrome is a condition that involves a congenital abnormality at the lumbosacral junction, characterised by the presence of a transitional vertebra. While this anomaly is often an incidental finding in imaging studies, it can sometimes be the source of significant lower back pain and discomfort. This blog will explore the anatomical features of Bertolotti’s Syndrome, its clinical manifestations, and the current approaches to managing the associated pain, supported by evidence-based research.

Anatomy of Transitional Vertebra

At the lumbosacral junction, where the lumbar spine meets the sacrum, a transitional vertebra represents a congenital anomaly where the last lumbar vertebra (L5) or the first sacral vertebra (S1) exhibits characteristics of both regions. This vertebra may partially or fully fuse with the sacrum or ilium, leading to a range of structural variations that can affect spinal mechanics.

Types of Transitional Vertebra:

• Type I: Dysplastic transverse processes that are enlarged but do not articulate with the sacrum.

• Type II: Incomplete lumbarisation or sacralisation, where a pseudo-articulation occurs between the transverse process and the sacrum or ilium.

• Type III: Complete lumbarization or sacralisation, where the transverse process fully fuses with the sacrum or ilium.

• Type IV: A combination of Types II and III, where one side of the vertebra is pseudo-articulated and the other side is fully fused.

  

(Original art by Heather Taillac, MD, Ochsner Clinic Foundation, New Orleans, LA. Published)

This anomaly was first described by Italian radiologist Mario Bertolotti in 1917, and the condition has since been associated with varying degrees of lumbar pain, although it is often discovered incidentally.

Clinical Manifestations and Symptoms

The presence of a transitional vertebra does not necessarily result in symptoms. Many individuals with this anatomical variation remain asymptomatic throughout their lives, with the condition often being detected only during imaging for unrelated issues.

However, when symptoms do occur, they are typically characterised by chronic lower back pain, often unilateral, that can radiate to the buttock or thigh. The pain is thought to arise due to several possible mechanisms:

• Altered Biomechanics: The abnormal articulation or fusion can lead to abnormal mechanical stress on the surrounding lumbar and sacral segments, resulting in degenerative changes and pain.

• Facet Joint Arthritis: The altered motion and stress can accelerate aged related changes in the facet joints, leading to arthritis and associated pain.

• Disc Degeneration: The transitional vertebra can cause abnormal distribution of forces across the intervertebral discs, increasing the risk of disc degeneration and associated radicular symptoms.

  
  

Incidental Finding or Cause of Pain?

While transitional vertebrae are often incidental findings, studies suggest that they can be a significant source of pain in some individuals. The prevalence of Bertolotti’s Syndrome is estimated to be between 4% and 8% in the general population, though not all individuals experience pain. A study by Tini et al. (1977) indicated that only about 11% of individuals with a transitional vertebra report associated lower back pain, suggesting that while the condition is common, symptomatic cases are less so.

Whether a transitional vertebra is the direct cause of pain can be challenging to determine. Diagnostic blocks, where an anaesthetic is injected into the area around the transitional segment, can be used to confirm the source of pain. If the block alleviates the pain, it supports the diagnosis of Bertolotti’s Syndrome.

Treatment and Management

Management of pain associated with Bertolotti’s Syndrome ranges from conservative approaches to more invasive interventions, depending on the severity of symptoms and the response to initial treatments.

1. Conservative Management

• Physical Therapy: Strength and conditioning and flexibility exercises are central to managing symptoms conservatively. A tailored physical therapy program can help reduce the biomechanical stress on the lumbar spine, alleviate pain, and improve function. It may also be able to identify and facilitate any psychosocial factors that could be contributing to symptoms.

  

• Medications: Nonsteroidal anti-inflammatory drugs (NSAIDs) and muscle relaxants are commonly prescribed to manage pain and inflammation. In some cases, a short course of corticosteroids may be considered to reduce acute inflammation.

• Activity Modification: Avoiding activities that exacerbate the pain, such as heavy lifting or prolonged sitting, can help manage symptoms. Ergonomic adjustments at work or home may also be beneficial.

  
  

2. Interventional Treatments

• Injections: Local anaesthetic and corticosteroid injections into the pseudo-articulation or affected facet joints can provide temporary relief. Radiofrequency ablation (RFA) of the affected nerves is another option that can offer longer-term pain relief by disrupting the nerve supply to the painful area.

• Epidural Steroid Injections: In cases where disc degeneration or radiculopathy (true sciatica) is present, epidural steroid injections may be used to reduce inflammation and alleviate nerve-related pain.

  
  

3. Surgical Intervention

Surgery is considered when conservative and interventional treatments fail to provide adequate relief, and the pain significantly impairs daily functioning. Surgical options include:

• Resection of the Pseudo-Articulation: Removal of the anomalous articulation to relieve mechanical stress on the spine and associated nerve compression. This procedure can lead to significant pain relief in selected patients.

• Spinal Fusion: In cases where instability or severe degenerative changes are present, spinal fusion surgery may be necessary to stabilise the affected segments. This approach is more invasive and carries higher risks, so it is usually reserved for severe cases.

  
  

Conclusion

Bertolotti’s Syndrome, while often asymptomatic, can be a significant source of chronic lower back pain in some individuals. Understanding the anatomical variations and the potential for pain generation is crucial for proper diagnosis and management. Treatment should begin conservatively, progressing to more invasive options, if necessary, with the goal of alleviating pain, improving function, and enhancing quality of life.

For those experiencing symptoms, a multidisciplinary approach involving physical therapy, pain management, and potentially surgical consultation is often the most effective way to manage this complex condition.

References

1. Tini, P. G., Wieser, C., & Zinn, W. M. (1977). The Transitional Vertebra of the Lumbosacral Spine: Its Significance in 850 Patients. Spine, 2(3), 162-168.

2. Aihara, T., Takahashi, K., Yamagata, M., Moriya, H., & Tamaki, T. (2000). Biomechanical Functions of the Transitional Vertebra with Lumbarization or Sacralization of the Lumbar Spine. Spine, 25(8), 779-783.

3. Santavirta, S., Tallroth, K., Ylinen, P., & Suoranta, H. (1993). Surgical Treatment of Bertolotti's Syndrome: Excision of a Transitional Vertebra's Abnormal Articulation. The Journal of Bone and Joint Surgery. British Volume, 75-B(5), 701-705.

4. Mirkovic, S., Schwartz, D. G., & Glazier, K. D. (2002). Surgical Management of the Painful Lumbosacral Transitional Vertebra (Bertolotti's Syndrome). Spine Journal, 2(2), 161-165.