Objective To prospectively assess the predictive power of centralization phenomenon in the curative effect of automated PLD.Methods The survey population was consisted of 109 patients with inclusion heraiation demonstrated by CT/MRI,74 men and 35 women with average age of 43.1 years(17～75 years). All were complained of low back pain,with varying degrees of lower extremity pain and altered sensation, lasting for more than 2 months;including one symptomatic disc in 99 patients and two symptomatic discs in 10 patients.Patients were undergone dynamic mechanical spinal test and reported whether the test would aggravate their pain.The assessment included forward flexion,extension,rotation of the trunk to the right and left, rotation to the left with fight extension,rotation to the fight with left extension,and whether straight leg raising in the supine position would aggravate back pain or leg pain.Symptom resposes were categorized into three groups:centralization group(CG),partial-centralization group(PCG)and noncentralization group(NCG). Centralization of pain is the progressive retreat of the most distal extent of the referred or radicular pain toward or to the lumbar midline.Noncentralization of pain is the peripheralization of pain in one or more directions, and no change in the distal-most pain location or intensity.All patients received a single therapy with PLD. Results A follow-up of 109 patients for 3 to 6 months,including 46 cases with 24 as exellent and 22 as good reaching 100% of excellent good rate in CG by MacNab standards;43 cases with 5 as exellent,29 as good,9 as fair and poor,with total effective rate of 79.1% in PCG.Twenty cases of NCG symptoms showed no improvement and therefore surgery was considered.Conclusions Centralization phenomenon occurrence during initial mechanical evaluation is a very accurate predictor for successful PLD outcome.Nonoccurrence of centralization would accurately predict poor PLD outcome and thus helpful as early predictor of the need for surgical treatment.