Anatomical Feasibility Of Extradural Transferring S2 And S3 Ventral Roots To S1 Ventral Root For Restoring Neurogenic Bladder In Spinal Cord Injury

Bladder dysfunction after spinal cord injury is a difficult problem in clinical.The reconstruction of the Xiao procedure achieves a breakthrough for spastic bladder.But at present,Xiao procedure was designed to increase the power of urination,ignoring the balance between urination power and resistance,which is contentious with widely accepted Brindley surgery.The applicant investigate the recovery of urinary dynamics and resistance balance by making best use of the advantages and bypassing the disadvantages of Xiao procedure and Brindley surgery of bilateral extradural cutting off S1 and S2 and tension-free transferring S2 and S3 ventral roots to S1 ventral root for restoring neurogenic bladder.Part1 Anatomical study of the extradural nerve roots of S1,S2 and S3Objective: The purpose of this study was to provide an anatomical basis for the treatment of spastic bladder dysfunction after spinal cord injury by the anatomical study of sacral 1,sacral 2 and sacral 3 spinal nerve root in this part,and accurate anastomosis of sacral 1 to sacral 2 and 3 ventral sacral root.Methods: 6 fresh frozen cadaver spine specimens were enrolled in the research.By exposing and dissecting the sacral segment of the spinal nerve root,the length of the spinal nerve root and the distance from the adjacent nerve root exits were measured.The ventral and dorsal roots of spinal nerve roots were separated according to anatomical characteristics.The fibrous structure of the ventral and dorsal roots was observed by HE staining,and the diameters of the ventral and dorsal roots of the spinal nerves were measured.NF200 staining was used to calculate the number of nerve fibers in the ventral and dorsal roots of the epidural spinal cord by Graphpad6.0 software.Results: Each extradural nerve root was located between the root exits of the nerve root and the corresponding intervertebral foramen,and the angle between the nerve root and the dural sac decreased gradually from the S1 segment to the S4 segment.The ganglion on each nerve root is located near the intervertebral foramen.The ganglion can be used as an anatomical marker to determine the scope of laminectomy;the number of nerve fibers in the ventral root of S1 is greater than the sum of the ventral root of S2 and the S3 ventral root nerve fibers(S1 ventral root nerve fiber number=8253 + 1419,S2 ventral root nerve fiber number =4766 + 1035,and S3 ventral root nerve fiber number =2233 + 299).Conclusion: The anatomical features of the extradural spinal nerve root in the sacral canal are described in detail in this part,which provides a data basis for the reconstruction of the reflex arc.It is preliminarily indicated that the anterior root of S1 can provide enough nerve fiber to restore the bladder urination.Part2 Anatomical feasibility of extradural transferring S2 and S3 ventral roots to S1 ventral root for restoring neurogenic bladder in spinal cord injuryObjective: The aim of this part was to establish a new type of reflex arc reconstruction by combining the operation of xiao’s reflex arc with the principle of Brindley operation to achieve the goal of coordinating the rebalancing of urination power and resistance.Methods: A total of 6 fresh frozen cadaver spinal specimens were used in this study.Starting from the coordination of the recovery of urination power and resistance,bilateral S2 and S3 posterior rhizotomy in epidural spinal canal were introduced into the spinal canal,and the bilateral anterior root of the epidural spinal canal was recombined with S2 and S3 anterior roots to reconstruct the reflex arc and correct spasticity.The coordination between bladder urination and resistance was analyzed,and the feasibility of the operation was analyzed from the perspective of anatomical structure.Results: The root nerve fibers of S1 and S2 and S3 were not intersecting in the epidural canal,and the ventral and dorsal root nerve fibers began to cross after the 5-10 mm in the dorsal root ganglion,and there was loose connective tissue between the dorsal root ganglion and the ventral root,and the dorsal root ganglion was separated from the ventral root,and the ventral root was easily separated.Dorsal root is linked to the dorsal root ganglion,which is a marker to identify the ventral and dorsal roots.It is also confirmed by the retrograde anatomy of the nerve root to the attachment site of the spinal cord.The ventral root of S1 was cut off at the distal 5-10 mm of the dorsal root ganglion,and the ventral root of S2 and S3 was cut off from the dural membrane.The proximal end of S1 and the distal S1 of S2 and S3 could be anastomosed without tension.There are two main bundles in the anterior root of S1.There is only one main beam in the ventral root of S2 and S3.The two main bundles of S1 can be anastomosed with S2 and S3 ventral root nerve bundles respectively.Conclusion: Use of the S2 and S3 VRs for extradural transfer to S1 VR for restoring bladder dysfunction is surgically feasible.