Contralateral C7 Nerve Transfer Surgery In The Treatment Of Spasmodic Paralysis

Background:Spasmodic paralysis caused by cerebral hemispheric damage caused by stroke,traumatic brain injury or cerebral palsy is a cause of long-term disability [1,2].Epidemiological studies have shown that the death rate from stroke has decreased,the disability rate has increased gradually,and it is now the highest among all diseases.About half of stroke survivors become severely disabled and lose activities of daily living [1,2].Relevant surveys show that 30-60% of patients cannot use the paralyzed arm after stroke [3].Clonic arm positions can impair daily activities,such as hygiene and dress,and may cause pain.Spasmodic arm palsy after central nervous injury has a long-term impact on the quality of life of patients.Functional recovery of the affected limb is one of the most difficult problems in clinical practice,and there is no satisfactory solution at present.Previous studies have shown that restoring ipsilateral motor cortex function on one side of a paralyzed limb is the physiological basis for functional recovery of a paralyzed limb.In the past,activation of ipsilateral motor cortex function was performed during rehabilitation;However,there is a large individual difference in this therapy,and the effect is not ideal [4].Contralateral C7 nerve transfer surgery is,in simple terms,a lateral incision of approximately 15 cm at the base of the neck.After bilateral brachial plexus nerves were exposed,the affected C7 was incised near the foramina and the contralateral C7 was incised at the junction of other brachial plexus nerves with C7.End-to-end nerve repair was performed by microsuture between the affected side and the healthy side through the prevertebral pathway.Postoperatively,the paralyzed upper limb was immobilized with a cephalic brace for 4 weeks.Then,regular rehabilitation treatment was performed on the affected upper limb,mainly including the same active movement,passive activity,occupational therapy,functional training,physiotherapy,acupuncture and massage,etc.[3].Transfer of the contralateral C7 nerve from the healthy side to the affected side to treat spastic hemiplegia caused by chronic brain injury.The clinical effect of the surgery was evaluated and it was proved that the surgery significantly improved the function of the paralyzed upper limb more than physical therapy alone [3].Nerve transfer is a new strategy for the treatment of central nervous system diseases,among which contralateral nerve cross transplantation is a new surgery for patients with hemiplegia,attracting much attention due to its effectiveness and wide indication range [5].In a recent landmark study,surgical intervention using contralateral C7 nerve transfer,an approach used to treat brachial plexus injury,has been implemented in patients with chronic stroke,demonstrating the additional benefits of standard rehabilitation strategies to improve motor performance and reduce affected limb spasms.[3,4,6] This procedure involves the transfer of the C7 nerve root and middle trunk from the uninjured limb to the injured limb using a short catheter that allows faster regeneration and instillation of the injured upper limb through the ipsilateral（contralateral）hemisphere,thereby improving motor performance and reducing spasms [7].This method is well tolerated in brachial plexus injury patients undergoing similar surgery [8],which is a new direction of neurosurgical intervention in stroke rehabilitation.Therefore,it is important for clinicians to understand the physiology,rationale,benefits and limitations of this approach.Objective:This study aims to the contralateral carotid 7 posterior nerve transposition in the treatment of upper limb paralysis after stroke 1 years later,evaluate and review the results of the contralateral C7 nerve transplantation in the safety and efficacy in stroke as well as the relevant neurophysiological change after transplantation of data are available,and further demonstrates the value of this surgery in the treatment of spastic hemiplegia.Methods:From September 2019 to March 2022,10 patients with central upper limb palsy underwent retrocervical transposition of the 7th nerve.Patients ranged in age from 20 to 68 years（mean: 41 years）.These patients included eight men and two women.Nine patients had cerebral hemorrhage and one patient had cerebral infarction.In addition,nine patients developed spasmodic paralysis of the upper extremity and one patient developed non-spasmodic paralysis.The duration of preoperative paralysis was 6-60 months（mean 26 months）.The procedure involved transposition of the contralateral cervical nerve root 7 through a posterior approach under general anesthesia.The patient was placed in supine position after general anesthesia.A 15-cm transverse incision was made at the neck root of the healthy side,2 cm above the clavicle,and the skin,subcutaneous tissue and platysma muscle were cut layer by layer.The lateral external jugular vein and its branches can be ligated or pulled apart.The fat pad at the posterior edge of sternocleidomastoid was cut to reveal the omohyoid muscle in the deep horizontal direction.Ligation or stretching of the transverse carotid artery to expose the scalenus anterior to protect the phrenic nerve running in front of the scalenus anterior;The ventral branch of the 5th cervical nerve was found along the cephalic end of the phrenic meridian,which combined with the 6th cervical nerve laterally to form the upper trunk.The middle trunk composed of the 7th cervical nerve was seen slightly deep in the caudal side of the upper trunk,and the lower trunk was found behind the middle trunk.The C7 nerve of the affected side was cut off at the proximal foramina,while the C7 nerve of the healthy side was dissociated as far as possible and cut off before it merged with other brachial plexus roots.Blunt dissection of the anterior C7 vertebral body was performed to expose the prevertebral esophagus and establish a pathway between the vertebral body and the esophagus.Then,the broken end of the healthy SIDE C7 nerve was led to the affected side through the prevertebral pathway,and the outer membrane suture was performed directly with the broken end of the affected side C7 under the microscope（no transplantation was required）,and the neck muscle and skin were sutured layer by layer.After the operation,the affected limb was fixed with a brachial brace for 4 weeks,and then the same rehabilitation treatment was continued as before,including active training,passive range of motion training,occupational therapy,functional training,physical therapy, acupuncture,massage and wearing of orthopaedic braces.The Fugl-Meyer Scale,Rankin Score,Barthel index,and H-S grading system were applied and analyzed to assess motor function of participants from preoperative to postoperative 12 months.Results:Results: The contralateral cervical 7 nerve was directly anastomosed with ipsilateral cervical 7 nerve,without nerve transplantation.After the operation,the patient was conscious and had normal upper limb movement on the healthy side,restrained by spasmodic lateral abdominal band.In postoperative follow-up,the muscle tension of the patient’s upper limbs on the spastic side was decreased,the motor ability and range of motion of the upper limbs on the spastic side were improved,and the self-care ability and quality of life were improved.There was no obvious dysfunction of the healthy upper limb and no postoperative complications.The muscle tension of fingers on the spasmodic side was lower than that before surgery,and most patients had mild numbness on the healthy side,which disappeared within 3 months after surgery.In all 10 patients,the length of the contralateral cervical 7th nerve was 6.84 ± 0.33 cm cm.In all patients,the unaffected 7th cervical nerve was directly anastomosed to the ipsilateral 7th cervical nerve,and no patient required additional nerve grafts.There were no complications.The esophagus,large blood vessels,pleura,or thoracic duct were not damaged during or after surgery.The fugl-Meyer score was used to evaluate the recovery after stroke and detect motor function impairment,and a higher score indicated better function.The spasm of the right upper limb was significantly reduced,the elbow joint could be placed vertically naturally,and the pain and temperature perception of the patient was improved compared with that before surgery.The patient walked freely,and the patient’s FUgl-Meyer score was from 35 to 51.Rankin score was used to evaluate the neurological recovery of patients after stroke from 3 to 2 points.（2 points: mildly disabled,unable to complete all pre-illness activities,but able to take care of their daily affairs without assistance;3 points: moderately disabled,with some assistance,but able to walk independently）;Barthel index was used to measure the functional status of patients’ daily living activities from 60 to 95,and the activity function was significantly improved.The H-S rating is based on major hand and upper limb movements and ranges from III to IV.Conclusion:For upper limb palsy after stroke,contralateral C7 nerve is directly anastomosed with ipsilateral C7 nerve by transposition of contralateral cervical 7 nerve through anterior vertebral approach,which is beneficial to nerve regeneration and functional recovery without nerve transplantation.This method is a safe and effective method to treat central palsy of upper limb after apoplexy.