Table 2. Characteristics of US-guided marking techniques of the included studies (n = 23)
Characteristic n %
Marking substrate    
          Dye 6 28.08
          Ink 2 8.69
          Latex 7 30.43
          Needles 3 13.04
          Other 5 21.73
Injected volume    
          1-2 drops 2 8.69
          3-4 drops 1 4.34
          0.1 mL 4 17.39
          0.5 mL 3 13.04
          1 mL 1 4.34
          1.5 mL 1 4.34
          2 mL 1 4.34
          3 mL 1 4.34
          n/c 9 39.13
Needle Size    
          ≤ 20-gauge 5 21.73
          21-25-gauge 11 47.82
          ≥ 26-gauge 2 8.69
          n/c 5 21.73
Qualification of Ultrasonographer    
          Investigator (qualification not described) 2 8.69
          Investigator (with experience) 4 17.39
          Radiologist 13 56.52
          Physical medicine and rehabilitation specialist 1 4.34
          n/c 3 13.04
Sample Size    
          1-5 11 47.82
          6-10 6 26.08
          11-15 2 8.69
          ≥ 16 4 17.39
Dissector    
          Anatomist 6 26.08
          Surgeon 6 26.08
          n/c 11 47.82
Accuracy    
         60-70% 1 4.34
         71-80% 3 13.04
         81-90% 2 8.69
         91-99% 1 4.34
         100% 15 65.21
         n/c 1 4.34
Int J Med Educ. 2024; 15:8-14; doi: 10.5116/ijme.65ae.4782