[Research on the depth and angle of needle insertion at Fengfu (GV16) in children based on three-dimensional image...

To explore the safety on the depth and angle of needle insertion in acupuncture at Fengfu (GV16)in children aged 2 to 6 years.

CT imaging data of cervical vertebra were collected from children aged 2 to 6 years.They were divided into 5 groups, i.e. 2-year old group, 3-year old group, 4-year old group, 5-year old group and 6-year old group, 20 cases in each one. The three-dimensional (3D) reconstruction was performed by importing the imaging data into the software, and Fengfu (GV16) was marked on the skin of the 3D model according to the anatomical landmarks positioning method. The hazardous depth of needle insertion was defined as the shortest straight-line distance from acupoint site on the skin to the bone structures corresponding to various dangerous organs. The hazardous angle of needle insertion was determined as the angle between the line from the acupoint site to the bone structure corresponding to dangerous organ, and either the horizontal plane or the sagittal plane. The hazardous depth and angle of needle insertion at this acupoint were measured, including the distance and angle from the acupoint site on the skin to the inferior border of the foramen magnum(D₁, A₁), to the posterior tubercle of the posterior arch of the atlas (D₂, A₂), to the superior border of the spinous process of the axis (D₃, A₃), to the lateral border of the upper part of the left/right vertebral arterial groove of the atlas (D_4L, D_4R, A_4L,A_4R), and to the upper lateral border of the left/right transverse arterial foramen of the atlas (D_5L, D_5R, A_5L, A_5R). The safety of acupuncture was analyzed on the depth and angle of needle insertion.

The differences in each hazardous depth were not statistically significant between the 3-year old group and the 2-year old group (P>0.05). D_5L and D_5R increased in the 4-year old group when compared with those in the 2-year old group (P<0.05), D₁, D_5L and D_5R were greater in the 5-year old group in comparison with those in the 2-year old group and 3-year old group respectively (P<0.05), and D_5R in the 5-year old group was greater than that of the 4-year old group (P<0.05). D₁, D₂, D_4L, D_4R, D_5L and D_5R in the 6-year old group increased when compared with the groups aged 2, 3 and 4 years respectively (P<0.05), D₃ in the 6-year old group was greater than that in the 2-year old group (P<0.05), and D_4L and D_4R in the 6-year old group were greater when compared with those in the 5-year old group (P<0.05). There was no statistical difference in the hazardous depth of needle insertion between the left and right in the same group (P>0.05). The variation of the safety in the insertion depth was largely consistent with that of hazardous depth of acupuncture. A₁ was larger in the 4-year old group compared with that in the 2-year old group (P<0.05), and it was decreased in the 6-year old group compared with that in the 4-year old group (P<0.05). A_4L, A_4R, A_5L, and A_5R were larger in the 4-year old group in comparison with those in the 2-year old group (P<0.05), while A_4L, A_4R, A_5L and A_5R were decreased in the 5-year old and 6-year old groups in comparison with those in the 3-year old and 4-year old groups (P<0.05).

When inserting the needle at Fengfu (GV16) along the sagittal plane within 10°, the depth should not exceed 20 mm for children under 5 years old, and not exceed 25 mm for those over 5 years old. When inserting the needle obliquely outward at 15° to 25°, the depth of insertion should not exceed 25 mm, and if the angle of insertion is in the range of 25° to 35°, the depth of insertion should be within 40 mm.