跟腱周围腓肠神经与小隐静脉解剖关系的MRI研究

MRI study on the anatomical relationship between the sural nerve and small saphenous vein around the Achilles tendon

目的探讨基于MRI的腓肠神经与小隐静脉在跟腱周围的解剖关系。方法横断面研究。纳入2021年10月—2022年8月解放军联勤保障部队第九二〇医院门诊招募的志愿者18名,其中男11名、女7名,年龄20~48[29(26,29)]岁,体质量50~80(65.5±9.3)kg,身高156.0~182.0(167.2±7.1)cm。志愿者均行双小腿中下段及双踝MR扫描,从跟骨结节至跟骨结节上18 cm处,每间隔1 cm层面测量腓肠神经与跟腱外侧缘交点距跟骨结节上缘水平面的垂直距离(Pn)、小隐静脉与跟腱外侧缘交点距跟骨结节上缘水平面的垂直距离(Pv)、小隐静脉至跟腱的最短距离(V-T)、腓肠神经至跟腱的最短距离(N-T)、腓肠神经至小隐静脉的最短距离(N-V)。观察指标:(1)分析Pn、Pv与身高和体质量的相关性。(2)在不同层面MRI中分别观察腓肠神经、小隐静脉、跟腱外缘走行特点。(3)对比不同层面MRI中V-T、N-T、N-V在不同性别和侧别间的差异及其与身高和体质量的相关性。(4)观察MRI中腓肠神经与小隐静脉的空间关系模式及各模式占比。(5)根据不同层面MRI中N-V测量结果计算腓肠神经走行参考范围,拟定腓肠神经损伤的相对危险区。结果(1)36侧下肢中,Pn为8.32~12.39(9.96±1.10)cm,Pv为7.46~14.1(10.43±1.56)cm。Pn、Pv均与身高呈正相关(r=0.34、0.43,P值均<0.05),与体质量均无相关性(r=0.18、0.26,P值均>0.05)。(2)V-T测量结果显示:小隐静脉在跟骨结节近端1 cm平面位于跟腱外侧(23.3±3.4)mm,向上走行过程中V-T逐渐减少,在跟骨结节近端10 cm平面已转至跟腱内侧,继续向上走行的过程中V-T逐渐增加,在跟骨结节近端18 cm平面位于跟腱内侧(-30.7±7.6)mm。N-T测量结果显示:腓肠神经走行特点与小隐静脉类似,在跟骨结节近端11 cm平面由跟腱外侧转入内侧。N-V测量结果显示:小隐静脉与腓肠神经在向上走行过程中逐渐靠近,在跟骨结节近端4~11 cm平面二者伴行紧密,跟骨结节近端11~18 cm平面后二者距离逐渐增加。(3)36侧下肢横断面MRI中,在10~18 cm层面女性V-T均大于男性,差异均有统计学意义(t=2.43~3.51,P值均<0.05),在其他层面不同性别间差异均无统计学意义(P值均>0.05);不同层面不同侧别间V-T差异均无统计学意义(P值均>0.05)。不同层面N-T、N-V在不同性别、侧别间比较,差异均无统计学意义(P值均>0.05)。相关性分析显示:在10~18 cm层面V-T与身高呈正相关(r=0.37~0.49,P值均<0.05),在其他层面V-T与身高均无相关性(P值均>0.05);不同层面V-T与体质量均无相关性(P值均>0.05)。不同层面N-T、N-V与身高、体质量均无相关性(P值均>0.05)。(4)腓肠神经与小隐静脉在跟腱周围存在4种伴行模式,腓肠神经位于小隐静脉前方20侧(55.6%),腓肠神经位于小隐静脉后方11侧(30.6%),腓肠神经与小隐静脉交错伴行2侧(5.6%),腓肠内侧皮神经与腓肠外侧皮神经未汇合并与小隐静脉伴行3侧(8.3%)。(5)各平面N-V测量结果95%CI从-10.6~18.6 mm递减至-2.1~2.0 mm,而后递增至-9.6~14.4 mm。经皮穿刺腓肠神经损伤的相对危险区:跟骨结节近端1~3 cm平面处小隐静脉及其前方2 cm、后方1.5 cm,4~11 cm平面处小隐静脉及其前方、后方0.5 cm;12~18 cm平面处小隐静脉及其前方1.5 cm、后方1 cm。结论小隐静脉与腓肠神经在跟腱周围走行特点相似,两者之间的距离相对恒定,在跟腱断裂经皮微创手术中可依靠小隐静脉的走行位置定位出腓肠神经的走行范围,可为定位手术安全区和避免腓肠神经损伤提供影像解剖学依据。

ObjectiveThis study aimed to explore the image anatomical relationship between the sural nerve and small saphenous vein around the Achilles tendon using MRI images.MethodsFor this cross-sectional study,18 volunteers were recruited from the outpatient clinic of the 920th Hospital of Joint Logistic Support Force of Chinese PLA from October 2021 to August 2022,including 11 males and 7 females aged 20-48(29[26,29])years with body weight of 50-80(65.5±9.3)kg and height of 156.0-182.0(167.2±7.1)cm.The mid-lower segments of their lower legs and ankles were subjected to magnetic resonance imaging,and measurements were taken from the calcaneal tuberosity to a point 18 cm above it,with intervals of 1 cm.At each level,the following vertical distances were measured:from the intersection of the sural nerve and the lateral edge of the Achilles tendon to the upper edge of the calcaneal tuberosity(Pn),from the intersection of the small saphenous vein and the lateral edge of the Achilles tendon to the upper edge of the calcaneal tuberosity(Pv),the shortest distance between the small saphenous vein and the Achilles tendon(V-T),the shortest distance between the sural nerve and the Achilles tendon(N-T),and the shortest distance between the sural nerve and small saphenous vein(N-V).The observation indicators were as follows:(1)correlation of Pn with height and body weight and correlation of Pv with height and body weight;(2)distinct anatomical features of the sural nerve,small saphenous vein,and lateral border of the Achilles tendon observed at various levels using MRI;(3)discrepancies of V-T,N-T,and N-V in MRI imaging across varying genders and lateralities and their correlations with height and body mass;(4)spatial relationship patterns and ratio of the sural nerve and small saphenous vein in MRI;(5)reference range for the course of the sural nerve calculated from N-V measurements obtained from MRI at various levels to establish the relative risk zones for peroneal nerve injury.Results(1)In the 36 lower limbs,Pn was 8.32-12.39(9.96±1.10)cm,and Pv was 7.46-14.1(10.43±1.56)cm.Both parameters showed a positive correlation with height(r=0.34,0.43,all P values<0.05)but no correlation with body mass(r=0.18,0.26,all P values>0.05).(2)V-T measurements indicated that the small saphenous vein was situated on the lateral side of the Achilles tendon at a distance of(23.3±3.4)mm from the proximal 1 cm plane of the calcaneal tuberosity.As it ascended,the distance V-T gradually decreased.When it reached the proximal 10 cm plane of the calcaneal tuberosity,the vein transitions to the medial side of the tendon continued its upward course.In this trajectory,the distance V-T progressively increased.Finally,at the proximal 18 cm plane of the calcaneal tuberosity,the vein was located on the medial side at a distance of(-30.7±7.6)mm.N-T measurement results demonstrated that the course of the sural nerve was similar to that of the small saphenous vein,transitioning from the lateral to the medial side of the Achilles tendon at a distance of 11 cm proximal to the calcaneal tuberosity.N-V measurements revealed that the small saphenous vein and sural nerve gradually approached each other during their upward course,running closely together at a distance of 4-11 cm proximal to the calcaneal tuberosity,with their separation increasing beyond 11 cm proximal to the calcaneal tuberosity.(3)In the transverse MRI of the lower limbs with 36 legs,the V-T of females was significantly higher than that of males at the level of 10-18 cm(t=2.43-3.51,all P values<0.05),but no statistically significant differences were observed between the genders at other levels(all P values>0.05).Statistical analysis showed no significant differences in V-T discrepancies between different levels and sides(all P values>0.05).Comparisons of N-T and N-V at different levels by gender and side also showed no statistically significant differences(all P values>0.05).Correlation analysis revealed a positive relationship between V-T and height at the 10-18 cm level(r=0.37-0.49,all P values<0.05),but no correlation was found at other levels(all P values>0.05).In addition,no correlation was observed between V-T and body mass at different levels(all P values>0.05)and among N-T,N-V,height,and body mass at different levels(all P values>0.05).(4)The sural nerve and small saphenous vein showed four concomitant patterns around the Achilles tendon.The sural nerve was anterior to the small saphenous vein in 20 sides(55.6%),posterior in 11 sides(30.6%),and intertwined in 2 sides(5.6%).Meanwhile,the medial sural cutaneous nerve and lateral sural cutaneous nerve did not converge and accompanied the small saphenous vein in 3 sides(8.3%).(5)The 95%CI for N-V measurements on each plane exhibited a notable decrease from-10.6-18.6 mm to-2.1-2.0 mm,followed by an increase to-9.6-14.4 mm.The relative risk area for percutaneous sural nerve injury encompassed the following locations:the proximal 1-3 cm plane of the medial malleolus with the small saphenous vein and its anterior 2 cm,posterior 1.5 cm;the 4-8 cm plane with the small saphenous vein and its anterior and posterior 0.5 cm regions;and the 12-18 cm plane with the small saphenous vein and its anterior 1.5 cm region and posterior 1 cm region.ConclusionThe small saphenous vein and sural nerve running around the Achilles tendon have similar characteristics.The distance between the small saphenous vein and sural nerve remains relatively constant.In percutaneous minimally invasive surgery for Achilles tendon rupture,the position of the small saphenous vein can be used to locate the course of the sural nerve,providing anatomical imaging evidence for the safe zone of surgery localization and avoiding sural nerve injury.