Abstract
Aim: This study aimed to evaluate, using ultrasonography, the morphological changes of the sciatic nerve in the dorsal thigh in terms of its cross-section area (CSA) in patients with unilateral S1 radicular symptoms. Methods: This observational study was performed in 15 participants (12 females; mean age 46.9 +- 9.9 years; mean body mass index 26.5 +- 4.7 kg/m2) diagnosed with unilateral S1 radiculopathy.
The CSA of the sciatic nerve was measured and evaluated bilaterally by ultrasound imaging at three levels of the dorsal thigh; at the gluteal fold, proximal quarter-thigh, and mid-thigh. The values for the symptomatic and asymptomatic sides of each patient were compared.
Results: The mean CSA values of the symptomatic (39.6 +- 15.6 mm2) and asymptomatic (32.9 +- 11.2 mm2) sciatic nerves at the level of the GF were measured. A significant increase of the CSA at this level on the patients' symptomatic side was observed (P = 0.02; d = 0.49, i.e., medium size of the effect).
At proximal quarter-thigh and mid-thigh levels, the side-to-side difference did not reach a level of significance. Conclusion: An enlargement of the nerve CSA at the gluteal fold level was observed on the symptomatic side with sciatica, while those changes were generally present during the period when the patient complained about the subjective symptoms.
Ultrasound imaging may be a useful, available tool to assess morphological changes of the sciatic nerve in unilateral S1 radicular symptomatic patients.