Inclusion and exclusion criteria

The inclusion criteria were as follows: age of 18 to 70 years; diagnosis confirmed by magnetic resonance imaging (MRI) and computed tomography and at least 1 month of conservative treatment with no satisfactory results; no previous surgical treatment at the same level of disk protrusion; no heart, liver, or lung conditions that may prevent surgical treatment; and agreement to undergo either PELD or MED and attend follow-up visits at the outpatient clinic.

The exclusion criteria were as follows: age of <18 years or >70 years; severe low back pain but no significant pathological change on MRI or computed tomography; a history of surgical treatment; severe heart, liver, or lung conditions that may prevent surgical treatment; and refusal or inability to accept surgical treatment and/or postoperative follow-up visits.