Localization Of Blocking Targets For The Spasticity Of The Anterior And Posterior Group Muscles Of Leg Based On The Nerve Entry Points And Muscle Spindle Abundance

Objective:To accurately localize the body surface projection location and puncture depth of nerve entry points?NEPs?and the centers of the highest region of muscle spindle abundance?CHRMSAs?of the anterior and posterior groups muscles of leg by body bony landmarks and spiral computed tomography scan.Methods:1.Twelve formalin-fixed Chinese adult cadavers?men,8;women,4?aged30⁷5 years at the time of death with no history of neuromuscular diseases,no knee or ankle joint deformations were chosen for this study.2.Reference line design:In order to localize the blocking targets of the anterior groups muscles of leg,a curved line on the patellar's skin surface starting from the lateral femoral epicondyle to the medial femoral epicondyle was selected as the horizontal reference line 1?H₁?;For the posterior groups muscles of leg,a curved line on the popliteal's skin surface starting from the lateral femoral epicondyle to the medial femoral epicondyle was selected as horizontal reference line 2?H₂?;A curved line on the skin surface starting from the lateral femoral epicondyle to the fibular lateral malleolus was selected as common longitudinal reference line?L?.3.Cadavers were dissected to expose the NEPs of each nerve branch to the anterior and posterior group muscles of leg and then these nerve branches were stained with barium sulfate.Spiral CT scanning and three-dimensional reconstruction image.4.Sihler's staining showed the intramuscular nerve dense regions?INDR?of the muscles in one side of the lower limb;HE staining muscle spindles in the corresponding parts of the INDR of the muscles on the other side of the lower limb,counting muscle spindles in each INDR and comparing their abundance;Barium sulfate was used to label the CHRMSAs,and then CT scan and three-dimensional reconstruction were performed.5.Measurements were do under Syngo system:the projection point of the NEP and CHRMSA on the body surface was designated as P,P by NEP or CHRMSA projecting on the opposite side of the body surface was designated as P'.The intersections that the vertical line and the horizontal line both through P with the line H and line L were designated as P_H and P_L,respectively;The percentage location of P_H and P_Lon the H and L and the depth of NEP and CHRMSA were determined.6.Statistical processing.Results:1.General anatomical findings:The anterior groups muscles of leg:The tibialis anterior muscle was innervated by two neuromuscular branches?ie,two NEPs?,the superior branch was thicker?localized?,and the inferior branch was thiner;One NEP was found for the extensor digitorum longus and extensor hallucis longus muscles.The NEP of tibialis anterior and extensor hallucis longus muscle were accompanied with vasculature.Superficial layer of posterior group muscles of the leg:Usually only one NEP was found for the medial heads of gastrocnemius,lateral heads of gastrocnemius and soleus muscles,and their NEPs were all accompanied with vasculature.The deep posterior compartment muscles of the leg:One NEP is for the tibialis posterior and flexor digitorum longus muscles,the most flexor hallucis longus muscle were innervated by two nerve branches?two NEPs?,the superior branch was thicker?localized?,and the inferior branch was thiner;These three muscles without accompanying vessels close to the NEPs.2.The projection position and depth of the NEPs of the anterior group muscles of the leg:The P_H of NEP of the tibialis anterior,extensor digitorum longus and extensor hallucis longus muscles were?5.61?1.03?%,?6.68?1.60?%and?6.25?0.89?%of the H₁ line,respectively.The P_L points were?23.75?2.49?%,?49.16?1.78?%and?35.98?2.58?%of the L line,respectively;The depth of NEPs through P were?27.75?2.51?%,?23.70?1.96?%and?30.73?1.22?%of the PP'line,respectively.3.The projection position and depth of the NEPs of the posterior group muscles of the leg:The P_H of NEP of the medial head of gastrocnemius,lateral head of gastrocnemius,soleus,tibialis posterior,flexor digitorum longus and flexor hallucis longus muscles were?46.89?2.73?%,?40.90?3.05?%,?42.56?2.59?%,?38.10?4.34?%,?55.21?3.60?%and?46.20?4.40?%of the H₂ line,respectively.The P_L points were?7.58?2.88?%,?8.15?2.52?%,?17.42?3.31?%,?25.35?3.94?%,?41.30?3.87?%and?45.39?3.59?%of the L line,respectively;The depth of NEPs through P were?16.32?2.52?%,?13.83?1.77?%,?29.93?2.89?%,?49.11?3.51?%,?54.64?3.98?%and?55.95?3.52?%of the PP'line,respectively.4.Sihler's staining showed as follows:The number of INDRs in the tibialis anterior,extensor digitorum longus,extensor hallucis longus,medial head of gastrocnemius,lateral head of gastrocnemius,soleus,tibialis posterior,flexor digitorum longus,and flexor hallucis longus muscles were 7,3,4,3,3,6,5,6 and 6,respectively.5.The projection position and depth of the CHRMSAs of the anterior group muscles of the leg:The P_H of CHRMSA of the tibialis anterior,extensor digitorum longus and extensor hallucis longus muscles were?35.37?2.99?%,?20.32?1.97?%and?32.37?2.05?%of the H₁ line,respectively.The P_L points were?46.14?4.21?%,?21.35?2.21?%and?50.25?3.08?%of the L line,respectively;The depth of NEPs through P were?18.37?1.78?%,?17.86?1.66?%and?32.24?2.55?%of the PP'line,respectively.6.The projection position and depth of the CHRMSAs of the posterior group muscles of the leg:The P_H of CHRMSA of the medial head of gastrocnemius,lateral head of gastrocnemius,soleus,tibialis posterior,flexor digitorum longus and flexor hallucis longus muscles were?56.87?2.78?%,?44.13?2.89?%,?75.77?4.16?%,?56.35?3.67?%,?60.79?4.26?%and?45.31?2.04?%of the H₂ line,respectively.The P_L points were?11.67?1.16?%,?9.26?1.03?%,?48.35?4.96?%,?43.04?2.28?%,?42.84?3.18?%and?52.55?2.33?%of the L line,respectively;The depth of NEPs through P were?16.39?1.57?%,?15.08?2.08?%,?37.55?4.07?%,?58.23?3.12?%,?44.41?3.31?%and?34.13?1.06?%of the PP'line,respectively.Conclusion:1.The body projection location and depth of NEP and CHRMSA are different in the same muscle.2.The body surface projection location and puncture depth of these NEPs and CHRMSAs should be recommended asthe optimal blocking target sites for the extramuscular neurolysis and intramuscular chemodenervation in the treatment of spasticity of the anterior and posterior groups muscles of leg,which is beneficial to improve the efficiency and efficacy of target block.