Here is the design of a clinical trial:

Official Title: Evaluation of Efficacy and Safety of Single and Multiple Therapy of Herbal Medicine/Chuna Therapy on Non-specific Chronic Low Back Pain: A Study Protocol for Multicenter, 3-arm, Randomized, Single Blinded, Parallel Group, Incomplete Factorial Design, Pilot Study -

Included conditions:
- Chronic Low Back Pain

Study Armgroups:
- {'label': 'SGHH', 'type': 'EXPERIMENTAL', 'description': 'Admission to Sogyeonghwalhyeol-tang granule', 'interventionNames': ['Drug: Sogyeonghwalhyeol-tang granule']}
- {'label': 'SGHH with manipulation therapy', 'type': 'EXPERIMENTAL', 'description': 'Admission to Sogyeonghwalhyeol-tang granule and manipulation therapy', 'interventionNames': ['Other: Sogyeonghwalhyeol-tang granule with manipulation procedure']}
- {'label': 'Placebo with manipulation therapy', 'type': 'PLACEBO_COMPARATOR', 'interventionNames': ['Other: Placebo with manipulation procedure']}

Interventions:
- {'type': 'DRUG', 'name': 'Sogyeonghwalhyeol-tang granule', 'description': 'Sogyeonghwalhyeol-tang herbal extract granule', 'armGroupLabels': ['SGHH']}
- {'type': 'OTHER', 'name': 'Sogyeonghwalhyeol-tang granule with manipulation procedure', 'description': 'Sogyeonghwalhyeol-tang herbal extract granule with manipulation procedure', 'armGroupLabels': ['SGHH with manipulation therapy']}
- {'type': 'OTHER', 'name': 'Placebo with manipulation procedure', 'description': 'Placebo granule with manipulation procedure', 'armGroupLabels': ['Placebo with manipulation therapy']}

Primary Outcomes:
- {'measure': 'Change from Baseline in Numeric Rating Scale of Pain', 'description': "A 10-point Numerical Pain Rating Scale (NPRS; 0: no pain, 10: maximum pain) assesses the patients' current level of pain.", 'timeFrame': 'Screening Visit, At baseline, week 2, 4, 6, 8'}

Please estimate the sample size based on the assumption: 
The sample size was considered based on LBP clinic visit rates, skilled labor availability, budget, and expected attrition at each site. It was not estimated based on previous studies.
2.5.4
          Sample size
          This is a pilot study to explore the efficacy of single or multiple therapies using SGHH and Chuna, feasibility of the study design and effect size for further large-scale studies. A sample size of 150 patients, which is not estimated based on previous studies, was considered after assessing their LBP clinic visit rates, skilled labor availability, budget, and expected attrition at each site.