Prevalence of extraforaminal nerve root compression below lumbosacral transitional vertebrae

Area of Science:

• Spinal imaging and anatomy
• Radiology
• Orthopedics

Background:

• Pathology above a lumbosacral transitional vertebra (LSTV) is a recognized cause of spinal symptoms.
• Nerve root compression below an LSTV is less commonly reported but can occur.

Purpose of the Study:

• To determine the prevalence of nerve root entrapment below LSTVs.
• To identify causes of this entrapment.
• To correlate findings with patient symptoms.

Main Methods:

• Retrospective review of lumbar spine MR and CT scans over 5.5 years.
• Identification of patients with "transitional vertebra" in reports.
• Assessment of nerve root compression below LSTV and correlation with clinical symptoms.

Main Results:

• 174 patients were included; 13% showed neural compression below an LSTV, primarily due to new bone formation.
• This compression was associated with pseudarthrosis from partial sacralization and incomplete fusion.
• Symptomatic correlation was found in 13% of those with compression and potentially in an additional 57%.

Conclusions:

• Nerve root compression below LSTVs occurs in 13% of cases and is symptomatic in up to 70% of affected individuals.
• Careful evaluation of the region below LSTVs is crucial for symptomatic patients.