PMC8581352_01
(A) The cross-sectional area of the extensor digitorum brevis of patient 1 before treatment was 0.312 cm2 (Circled by a dotted line); The Triangle refers to the fourth and fifth metatarsal bones. (B) The cross-sectional area of the extensor digitorum brevis increased to 0.428 cm2 (Circled by a dotted line) after two courses of treatment; The Triangle refers to the fourth and fifth metatarsal bones.
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f1
The extensor digitorum brevis (EDB) muscle had significantly atrophied by 0.32 cm2 ( Figure 1A ), and the strength of the extensor of the thumb was grade 0/5 with steppage gait ( Table 1 ). The cross-sectional area of the EDB was 0.43 cm2 after two courses of treatment ( Figure 1B ). The other changes are shown in  Tables 3  and  4 .
PMC8581352_02
PMC8581352_03
PMC8581352_04
PMC8581352_05
Patient 2 was treated with mecobalamin by ultrasound-guided hydrodissection injection at the malleolus medialis of the posterior tibial nerves (A-E). (A) A normal posterior tibial nerve is shown as a clear neural boundary (cribriform network), normal internal echo (the posterior tibial nerve is below the red arrowhead). (B) The posterior tibial nerve of patient 2 was thickened with a fuzzy boundary in the medial malleolus (the red arrowhead indicates the posterior tibial nerve). (C) Injection with 3 ml saline at the medial malleolus of the posterior tibial nerve (the posterior tibial nerve at the red arrowhead, the point of a needle at the blue arrowhead, and the green arrowhead points to saline after injection). (D) The posterior tibial nerve was injected with mecobalamin at the medial malleolus after injection in the transverse section, and it can be seen that the solution is evenly wrapped around the posterior tibial nerve (red arrowhead pointed to the posterior tibial nerve, saline + mecobalamin at the green arrowhead). (E) The medial malleolus of the posterior tibial nerve after injection with mecobalamin in the longitudinal section, it can be seen that the fluid evenly covers the posterior tibial nerve (the red arrowhead points to the posterior tibial nerve, and saline + mecobalamin at the green arrowhead). MM; Medial malleolus.
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f2
The posterior tibial nerve was displayed with a clear neural boundary, an internal echo, and a honeycomb-like structure by high-resolution ultrasound ( Figure 2A ). About 45 -60  was required between the needle and sonographic probe ( Figure 2B ). At the end of the hydrodissection, a hypoechoic ring could be observed on the transverse axis ( Figure 2C ). Then, the needle tip was kept still and substituted with the second syringe to inject 1.5-2 ml of solution into the target nerve at each injection point ( Figure 2D ). The surrounding liquid around the nerve was shown clearly on the longitudinal axis ( Figure 2E ), after which the needle was removed.