The aim of the present study is to assess the effectiveness of acupuncture using Yamamoto's method for the treatment of ANLBP using the following outcomes:pain,functional capacity,quality of life and number of 50 mg sodium diclofenac pills taken per day.

A randomized, controlled, double-blind, prospective trial is being conducted involving 80 patients with low-back pain defined as pain and discomfort localised bellow the costal margin and above the inferior gluteal folds, for a period of less than 30 days and unrelated to any specific etiological factors. Patients are being recruited from the university hospital of the Federal University of Sao Paul (UNIFESP)and exams were carried out by a rheumatologist. The patients are randomly assigned to either intervention group (IG) and are submitted to five acupuncture sessions or placebo group (PG) and are submitted to five non-penetrating acupuncture sessions. Both groups are recommended to take 50 mg of sodium diclofenac every eight hours for lumbar pain, if needed and record the number of pills on a standardized form.

The patients are instructed not to use other medications or therapies for low-back pain during the study.The IG are submitted to acupuncture by a physician acupuncturist with eight years experience in the technique. Five acupuncture session are performed at baseline, D3, D7, D14 and D21. Specific needles for scalp acupuncture and tubes that guide these needles, called mandrels are unpacked in front of the patient. The stainless steel needles: 0.20 x 13 mm, sterilized and disposable.Sessions last 20 minutes. The patient remain seated, using a hat with a central orifice exposing the area to receive the needles. The hat has a wide brim to keep the patient blinded for the procedures. The needle penetrates the skin at an approximately 15º angle and a depth of 0.3 to 0.5 cm. The PG are submitted to five placebo acupuncture session performed by the same acupuncturist with same material and hat, but penetration did not occur and only the mandrel came into contact with the skin. All patients are blind to which procedure they are receiving. The basic points D, H and I and kidney, bladder and liver points of Yamamoto's method are used as standard treatment to ANLBP for the both groups.

Evaluations: The IG and PG are evaluated six times between baseline and Day 28 immediately before and after each acupuncture session. Outcome measures are recorded by a single assessor blinded to group allocation.

D0: baseline; D3: three days after baseline; D7: seven days after baseline; D14: fourteen days after baseline; D21: twenty-one days after baseline and D28: twenty-eight days after baseline.

Losses: Participants absent from more than three acupuncture sessions and evaluations are considered losses.

Placebo credibility: At the end of the study, participants are asked about which group they believed they belonged.

Sample size: To achieve an improvement in VAS pain of 2.0 point, with a significance of 0.05, and a power of 0.90, a minimum of 40 patients per group is necessary as a previous compensation for the possible 20% loss at follow-up.

Statistics: An intention-to-treat analysis are performed, using the last-observation-carried-forward method. A level of significance of p < 0.05 (2-tailed tests) are accepted for the trial. For normally distributed data, the variables are analysed using repeated-measures analysis of variance (ANOVA). The analysis are performed between groups (acupuncture versus non-penetrating acupuncture; between subjects factors) and over the time (baseline, 3, 7, 14, 21 and 28 days; within subjects factors). Categorical data measured over time are analysed using repeated-measures analyses of variance (ANOVA) for categorical data. A 95% confidence interval (95% CI) are used. The Student's t-test are used to compare numerical variables with normal distribution at one time and the chi-square test or Fisher's exact test are used to determine differences in rates of improvement between the two groups. The Kappa index are used to determine agreement on the LIKERT assessment between patient and assessor. All tests are performed using SPSS version 15.0 and MINITAB 14.0

Inclusion Criteria:

• Male or female
• Aged 18 to 65 years
• Seeking medical assistance for nonspecific low-back pain
• Score of 4 to 8 cm on the pain scale (0 to 10 cm)
• Agreed to participate and signed term of informed consent

Exclusion Criteria:

• Patients with a diagnostic investigation of secondary causes as spondyloarthropathy, infection, tumor or fracture
• Sciatica lumbar pain
• Previous surgery on spinal column
• Litigation
• Having changed physical activity or underwent acupuncture or physical therapy in previous three months,
• Having previously undergone scalp acupuncture
• Pregnancy
• Contraindication for anti-inflammatory agents

Non-serious adverse events were collected during de follow-up (28 days).

80 patients were evaluated in the end of the study and non-serious adverse events were observed.