Analisis multivariat dan kesintasan faktor-faktor yang memengaruhi luaran klinis indeks disabilitas oswestry pada pasien hernia nukleus pulposus pada vertebra lumbar pasca tindakan microendoscopic discectomy = Multivariate and survival analysis of factors that influence the clinical outcome of oswestry disability index in patients with herniated nucleus pulposus lumbar vertebral post microendoscopic discectomy