Applied Anatomy Of Intrusive Opertions Of Lumbar Intervertebral Foramen

Objective:1. To dissect, observe and record the occurrence, start-stop position, move towards and contiguity of ligaments of lumbar intervertebral foramina, in order to probe into the morphology of ligaments of lumbar intervertebral foramina and clinic problems such as the danger and uncertainty to cut ligaments using Zhendao.2. To dissect, observe and record the occurrence, start-stop position, move towards and contiguity of segmental arteries, ascending lumbar veins, segmental veins, lumbar branch of iliolumbar veins of lumbar intervertebral foramina, in order to provide morphology for lumbar intervertebral foramina surgeries.3. To dissect, observe and record the location and contiguity of 2 relatively lacking blood vessel and nerve zones (triangular working zones, security triangle), in order to provide morphology for intrusive operations of lumbar intervertebral foramina such as surgeries and injections.Methods:Dissected, observed and recorded the blood vessels, ligaments, nerves, their adjacent relations through L1-2～L5/S1 intervertebral foramina on 10 antiseptic cadaver specimens after that part of the skins, fasciae, muscles were eliminated from the lumbar spine and fats and laminae of vertebral was removed from intervertebral foramina when necessary. Results:1. Ligaments in lumbar intervertebral foramina and its lateral area(1) Ligaments in lumbar intervertebral foramina entrance zones and central zones There were no ligaments found on lumbar intervertebral foramina and its lateral werea. Only some things like fibrous tissue was found that connected on neurovascular and lumbar intervertebral foramina entrance zones and central zones. And adipose tissue was so rich that it could fill to the full on spinal canal and lumbar intervertebral foramina.(2) Ligaments in lumbar intervertebral foramina exit zones There were two group ligaments named superior transforaminal ligaments and inferior transforaminal ligaments in lumbar intervertebral foramina.①Superior transforaminal ligaments, which started at periphery of isthmian part of lumbar vertebral arch and stopped at inferolateral vertebral body and the lateral of posterior longitudinal ligaments, passed through the upper of lumbar intervertebral foramina. There were only 8 superior transforaminal ligaments in L1-2-L3-4and 4 in L3-4 of all 100 lumbar intervertebral foramina.②Inferior transforaminal ligaments, that started at the junctions of transverse process root and superior articular process, the front of superior articular process and stopped at the lateral posterior longitudinal ligament, the same segment of lumbar vertebral body or disc, were bulky in L1-2～L3-4 and slender or missing in L4-5,L5/S1. There were only 43 inferior transforaminal ligaments in L1-2-L34 and 2 in L3-4 of all 100 lumbar intervertebral foramina.③Lumbar intervertebral foramina exit zones were divided to 3 holes by transforaminal ligaments. And there were superior lumber intervertebral veins in the smaller superior holes, lumber nerves and lumber branches of segmental arteries in the bigger middle holes and inferior intervertebral veins in the smaller inferior holes. (3) Ligaments in lateral lumbar intervertebral foramina①Almost all corporotransverse ligaments, which were distributing in L5/S1 lumbar intervertebral foramina, were divided into corporotransverse superior and inferior ligaments. Corporotransverse superior ligaments started at the same segment inferior outside of the vertebrae, the lateral annulus fibrosus or superior outside of the lower vertebrae, and stopped at the lower part of transverse process. Corporotransverse inferior ligaments started at the same segment superior outside of the vertebrae, the lateral annulus fibrosus or the superior outside of the upper vertebrae, and stopped at the upper part of ala of sacrum.5 corporotransverse superior ligaments and 2 corporotransverse inferior ligaments were found in all the 20 L5/S1 lumbar intervertebral foramina in this experiment and no corporotransverse ligament was found in other lumbar intervertebral foramina.②L5/S1 lateral lumbar intervertebral foramina were divided into 3 holes by corporotransverse ligaments. That were anterosuperior hole, posterior hole and anteroinferior hole. There were communicating branches of lumbar sympathetic and anterosuperior branches of intervertebral vein in the smaller anterosuperior hole, and posterior branch of intervertebral vein and lumber branch of iliolumbar vessels in the bigger posterior hole, and 5th lumber nerve and sometimes inferior intervertebral vein in the smaller anteroinferior hole.③Tendinous arch of intertransverse ligament strated extensively at inferior vertebral notch, inferomedial mamillary process and inferolateral isthmian part of lumbar vertebral arch, and posterolaterally merged together with intertransverse ligament, and downward stopped at anterosuperior transverse process root and superior articular process. Tendinous arch travelled obliquely, and was vertical and accompanying with posterior branch of lumber nerve and its dorsal branch. Tendinous arch which was found in L1-2-L4-5 but no in L5/S1 lumbar intervertebral foramina, sometimes diverged with a branch to zygapophysial joint and look like the shape of E. Posterior branch of lumber nerve, its dorsal branch and superior joint vessel were distributing in the upper of the E, and the inferior joint vessel was distributing in the inferior of E.2. Nerves in lumbar intervertebral foramina and its lateral areaLumbar nerves were fixed by fibrous tissue in lumbar intervertebral foramina central zones, and were distributing in the above of inferior transforaminal ligaments and under the superior transforaminal ligaments in lumbar intervertebral foramina exit zones, also were distributing in the above of corporotransverse inferior ligaments and under the corporotransverse superior ligaments in lateral lumbar intervertebral foramina. Bifurcation of anterior and posterior branches of lumber nerve was closing to the tendinous arch, and lumbar nerve look like Y that forked alongside tendinous arch. Communicating branches of lumbar sympathetic connected to lumbar nerves in the lower of ventral lumbar intervertebral foramina and its lateral area.3. Arteries in lumbar intervertebral foramina and its lateral areaL1-4 segmental arteries were divided into 3 terminal branches named anterior branch group, middle branch group and posterior branch group in lumbar intervertebral foramina. Lumbar branch of iliolumbar artery or branch of L4 segmental artery went into the L5/S1 lumbar intervertebral foramina. And there were 11 lumbar branches of iliolumbar arteries and 6 branches of L4 segmental arteries which went into the L5/S1 lumbar intervertebral foramina and no artery in 3 intervertebral foramina in all 20 intervertebral foramina4. Veins in lumbar intervertebral foramina and its lateral area Intervertebral veins, that were separated from vertbral venous plexus, transfused into lumbar vein or ascending lumbar vein which also accepted the branches of posterior outer vertebral venous plexus. Intervertebral vein were separated from anterior or posterior outer vertebral venous plexus that were divided into inferior and superior branches including 1-3 branches which were distributing above superior transforaminal ligaments and down inferior transforaminal ligaments. There were usually no intervertebral vein in L5/S1 lumbar intervertebral foramina. But some linking vein between intervertebral vein and lumbar veins were observed in triangular working zones upon root of transverse process in this experiment5. Triangular working zones(1)Triangular working zones upon root of transverse processus (usually named triangular working zones of lumbar intervertebral foramina or security triangle) were constituted by anterior and posterior branches of lumbar nerves, superior articular process and the upper of root of transverse process. But ascending lumbar vein and linking vein between intervertebral vein and lumbar veins were observed in some triangular working zones upon root of transverse process. These two veins were thin wall, large diameter.①67 linking veins between intervertebral veins and-lumbar veins were found in all 100 lumbar intervertebral foramina. And of all the 67 linking veins, there were 12 threading in the center of this triangular working zones, and 27 in the flanking region and 28 in the lateral region or facies anterior.②Ascending lumbar veins were found in 16 in all 20 lateral region.3 ascending lumbar veins were threading in the center of this triangular working zones, and 14 in the flanking region and 36 in the lateral region or facies anterior in all 100 lumbar intervertebral foramina. Ascending lumbar vein and linking vein between intervertebral vein and lumbar veins were observed in the center of 12% triangular working zones upon root of transverse processus. (2) Triangular working zones outsides lanmina of vertebral arch, which were area of relatively without vessels and nerves, were located adjacent two roots of transverse process or root of transverse process and ala of sacrum and were closing to the outer of lanmina of vertebral arch. These triangular working zones were constituted by hemline of the outer of lanmina of vertebral arch and zygapophysial joint, a side of the superior joint vascular, a side of the inferior joint vascular and posterior branch of lumber nerve.Conclusion:1. Ligaments in lumbar intervertebral foramina were transforaminal ligaments which were mostly distributing in the upper of intervertebral foramina and corporotransverse ligaments which were mostly distributing in the lower intervertebral foramina. As they were low rate in appearance, high rate in variability, and adjacent with lumber nerves and vessels, Zhendao cutting blindly here was dangerous and meaningless which would be cautious.2. We supported that the role of ligaments in lumbar intervertebral foramina would be discussed in physiology and pathology conditions. (1) In physiology condition, firstly ligaments could fix the lumber nerves and avoid that meninges and spinal cord were torn when the nerves were tearing. And secondly they could prop up the nerves to avoid that nerves could be entrapped by the small lower of intervertebral foramina which mostly presented to be key eye shape and and sometimes triangle, Thirdly they could protect vessels especially the superior branches of intervertebral vein which would be oppressed by lumber nerves if there was no inferior transforaminal ligaments. (2) In pathology condition such as trauma and regression, lumbar nerve root could not elude from the hyperplastic zygapophysial joint and the herniated disc for that foraminal space was narrow and nerves were fixed by ligaments. 3. Lumbar intervertebral foramina exit zones were almost sealed with nerves and blood vessels. Two relatively lacking blood vessel and nerve zones (triangular working zones) were sat beside lamina of vertebralar arch and midpoint of the line of two adjacent roots of transverse process, and upon root of transverse process. But ascending lumbar vein and linking vein between intervertebral vein and lumbar veins were observed in 12% triangular working zones upon root of transverse process. Triangular working zone was relatively without blood vessels existence. Attentions should paid to the veins that exist in admission passage zone for intrusive operations of posterior-lateral lumbar vertebra. Intervertebral foramina puncture was recommended to prick beside lamina of vertebralar arch and midpoint of the line of two adjacent roots of transverse process. As lumbar intervertebral foramina exit zone was almost sealed with nerves and blood vessels, blind acupotomy was dangerous in here.