The effect of popliteal sciatic nerve block with methylprednisolone in the management of postinjection sciatic neuropathy after clinical and electrophysiological examination.

BACKGROUND

This study aimed to investigate the effects of popliteal sciatic nerve block (PSNB) in the treatment of postinjection sciatic neuropathy (PISN) resistant to conservative treatments.

METHODS

Patients diagnosed with PISN were included in the study. A damaged branch of the sciatic nerve was detected after neurological and electrophysiologic studies (EPSs). Visual analogue scale (VAS) was administered before, one hour after, and one month after the procedure. Also Leeds Assessment of Neuropathic Symptoms and Signs pain scale (LANSS) was administered before and one month after the procedure. The effects of EPSs findings and loss of muscle strength on the VAS and LANSS scores that measured after PSNB were evaluated.

RESULTS

PSNB was performed in 17 patients (12 males and 5 females) with a diagnosis of PISN. Their mean age was 54.95 ± 12.55 years, and the mean duration of symptoms was 3.53 ± 1.28 months. The EPS findings revealed a lateral truncus injury in 5, a medial truncus injury in 3, and injury to both in 9 patients. The initial muscle power scale scores were grade 0 in 2, grade 2 in 1, grade 3 in 7, grade 4 in 5, and grade 5 in 2 patients. The initial VAS and LANSS scores were 7.53 ± 1.06 and 17.35 ± 3.12. The mean VAS scores at the first hour and one month after the procedure decreased to 2.53 ± 1.70 and 4.18 ± 1.74 while the mean LANSS score one month after the procedure was reduced to 7.88 ± 5.84. The effects of EPSs findings and loss of muscle strength were found significant (p = 0.001), but the duration of symptoms was not found significant (p = 0.36) on the VAS and LANSS scores that measured after PSNB.

DISCUSSION: The outcome of this research proved the effectiveness of PSNB with methylprednisolone in the management of PISN, especially in patients whose pain was located below the knee. EPSs findings and loss of muscle strength indicated the severity of the nerve damage affect the success of PSNB in pain management, but the length of time that elapsed after the nerve injury did not.