The Clinical Application And Anatomical Basis Of The Transforaminal Blocking Of Sinuvertebral Nerve In The Diagnosis Of Discogenic Low Back Pain

Although discogenic low back pain accounts for 26%-39%of the total number of patients with low back pain,the diagnosis of discogenic low back pain is still difficult.Discography has some value in the diagnosis of discogenic low back pain,and is even called the "gold standard".However,it has many problems,such as false positives,false negatives,and iatrogenic disc injury caused by the operation.Therefore,this method has been highly controversial.Although some people believe that annulus fibrosus tear,as a high intensive zone on lumbar magnetic resonance T2W,which can be considered as the source of pain,it is not reliable for the diagnosis of discogenic low back pain.According to literatures report,as an important part of the lumbar nerve network,the sinuvertebral nerve is involved in the formation and conduction of discogenic low back pain.Therefore,the operation on the sinuvertebral nerve for diagnosing and treating the discogenic low back pain has become a new focus.Since the sinuvertebral nerve is mainly distributed in intervertebral disc,dural sac and posterior longitudinal ligament,among which intervertebral disc lesions are more common,while dural sac and posterior longitudinal ligament lesions are rare,pain signals are mainly from intervertebral disc.Transforaminal blocking of the conduction of pain signals by the sinuvertebral nerve to diagnose discogenic low back pain,which has the advantages of less trauma,low cost and safety.However,the anatomical knowledge of the sinuvertebral nerve is still not very comprehensive,and its origin,course and distribution are still controversial,which will affect the effect and accuracy of the block.Therefore,we intend to further clarify the anatomical characteristics of the sinuvertebral nerves by dissecting the cadavers,and verify the diagnostic value of transforaminal blocking of sinuvertebral nerve in discogenic low back pain.Objective:To study the neuroanatomical features of the lumbar sinuvertebral nerve,and to further verify the diagnostic value of transforaminal blocking of sinuvertebral nerve in discogenic low back pain.Methods:8 spine blocks(including vertebral bodies L1-S1),corresponding to 8 embalmed human body-donors belonging to the Department of Anatomy,Southern Medical University,were dissected.The origin,number and spatial distribution of lumbar sinuvertebral nerves were observed under surgical microscope.Nerve tissue which was suspected was confirmed by Immunohistochemical method for neurofilament 200(NF200)and protein gene product 9.5(PGP9.5).Meanwhile,the distance between the lower edge of the pedicle and the lower edge of the corresponding vertebral body in the lumbar 1-5 segments of normal adults was observed.A retrospective study of 32 patients diagnosed with discogenic low back pain admitted to the Hospital from April 2020 to November 2021.All of these patients underwent sinuvertebral nerve block at the responsible segment during hospitalization.The VAS scores and ODI scores before surgery,3 days after surgery,lweek,1 month and 3 months after surgery were statistically analyzed.Results:The lumbar sinuvertebral nerves were divided into two subtypes:Deputy branches,which originated from the ventral side of the dorsal root ganglion or the origin of the gray rami communicans,and distributed directly to the posterolateral side of the vertebral body and intervertebral disc.Main branch,which is similar to the origin of the deputy branch of the sinuvertebral nerve,enters the spinal canal along anterior wall of the spinal canal.After immunohistochemical experiments,it was determined that the suspected deputy branch of the sinuvertebral nerve was nerve tissue.The average distance between the origin of the sinuvertebral nerve and the lower edge of the pedicle of the upper vertebral body and the upper edge of the lower pedicle is(12.92±4.57mm and 8.51±5.86mm for the Ll/2 segment,13.88±3.96mm and 7.12±4.34mm for the L2/3 segment,12.35±4.38mm and 10.58±5.09mm for the L3/4 segment,13.54±4.16 mm and 10.32±5.66mm for the L4/5segment,13.52±4.89mm and 10.85±6.31mm for the L5/S1 segment).The distance between the origin of the sinuvertebral nerve and the lower edge of the pedicle of the upper vertebral body is relatively constant.The distance between the lower edge of the pedicle of the upper vertebral body and the lower edge of the vertebral body in the L1-5 segments of the normal persons(11.23±1.13mm for the 1st segment,11.38±0.86mm for the 2nd segment,11.3 8±1.14mm for the 3rd segment,10.13±0.99mm for the 4th segment,and 9.33±0.86mm for the 5th segment).Hence,we chose the blocking point at the intersection of the line connecting the lower edge of the upper vertebral body and the lateral edge of the pedicle.32 patients with discogenic low back pain underwent sinuvertebral nerve block(0.66%lidocaine solution 0.3ml).A total of 24 patients(75.0%)had significant relief of low back pain within 3 days after surgery without recurrence,which was defined as a positive result of the sinuvertebral blocking test.The VAS/ODI scores at each time point after operation were significantly different from the corresponding results before operation(P<0.05).The low back pain of the patients was significantly improved after the operation,and the VAS improvement rates at the 4 follow-up time points were 56.52%,54.34%,38.61%and 34.26%,respectively.The improvement rates of ODI at four follow-up time points after operation were:46.98%,48.33%,39.80%and 34.24%,respectively.Conclusion:The transforaminal blocking of sinuvertebral nerve in the diagnosis of discogenic low back pain is a safe and effective method for the diagnosis of discogenic low back pain,and has a certain therapeutic effect.Although this method is not yet a substitute for discography,it can still be used as one of the options for the diagnosis of discogenic low back pain.