Clinical Observation Of Contralateral C7 Transfer For Total Root Avulsion Of Brachial Plexus Injury

Objective:As the development of the traffic facilities,the rate of trauma caused by traffics is rising,and the prevalence of brachial plexus injury especially the total root avulsion of brachial plexus injury is drastically increasing every year.It is accepted that the operation way of multi-donor nerve transfers is effective to the injury.Furthermore,the repeatedly-improved way of contralater C7 transfer,which was firstly invented 20 years ago,has become an important method to treat the brachial plexus injury.Therefore,the research into the impact of contralater C7 transfer on the donor extremity has become the focus throughout the field of the peripheral nerve surgery. The nerve roots of C7 ,C8 and C9 have highly overlapping control domains,so the domain controlled by C7 is very diffusedly distributed,and it will not cause severe functional disabilities of donor extremity even after the cut of C7.And it has been reported that during the follow-ups,severe functional disabilities of donor extremity and neurogenic pains were found in some patients after the cut of contralateral C7,but the severity was different according to the various reports and the injury mechanism needed to be further investigated. In this study patients with total root avulsion of brachial plexus injury were recruited and underwent contralater C7 transfer or other donor nerve transfers according to the injury severity.We aim to retrospectively observe the recovery of the affected extremities and the impacts on the donor sides, so as to provide more evidence to expand the use of the contralater C7 transfer in clinics.Methods:28 patients,who were admitted to our department with total root avulsion of brachial plexus injury and had received the treatment of contralater C7 transfer or other donor nerve transfer from July 2004 to July 2010 were recruited for this study.The clinical data was collected and analyzed retrospectively.Diagnosis:By preoperative clinical examinations, electromyography and MRI tests,the C5~T1 root avulsion of brachial plexus injury was firstly diagnosed and further certified after the exploratory operation and myoelectric conduction test.Among all of the patients,six were combined with phrenic nerve injury,one with accessory nerve injury and seven with both of them. Operational treatment:Reconstruction of contralater C7 transfer and other donor nerve transfers were performed in the patients and upper trunk, radial or median nerve of the injured limb were reconstructed by whole or partial contralateral C7 depending on the sizes of cross-section of the nerve graft. Immediate functional disturbances on the donor side were monitored in all patients and long-term deficits were evaluated in 26 cases with follow-up over 12 months;motor and sensory recovery were assessed in twenty-one patients with follow-up over 24 months.The follow-up observation included: touch sensation, algesia and two point discrimination in the donor finger pulps and the affected extremity, muscle strength of the affected extremity.It was finally assessed by the MRC sensation classification criteria (U.K.) and MRC myodynamia classification criteria (U.K.). Effects on the unaffected side sensation were analyzed three days and one year respectively after the operation,and the different degrees were analyzed by the rank sum test;recovery of two point discrimination in the donor finger pulps was analyzed by Chi-Square test.Statistical significance was set at a<0.05. These statistical analyses were performed with a computer software program for Microsoft Windows(SPSS,13.0).Results:Functional recovery (>M2+) was achieved in 60% of cases(three of 5) for the supraspinatus neurotization, 80% of cases(four of 5) for the biceps, 62.5% of patients(five of 8) for the wrist and finger flexors, 20% of cases(one of 5) for the deltoids, 33% of cases(four of 12) for the triceps, and 37.5% of cases(three of 8) for the wrist extensors.Sensitivity was not well recovered due to our selection of posterior division of C7 transfering to affected medial part of median nerve. All of the patients presented different degrees of hypofunction in the contralateral sides.Three days after operation:one case without obvious effects on the sensation of the contralateral side,nine cases with S3+,eleven cases with S3+,seven cases wih S2,difference between the effects of posterior division of C7 transfering and the whole C7 transfering was significant(P<0.05) ;one year after the operation: sixteen cases without obvious effects on the sensation of the contralateral side,nine cases with S3+,eleven cases with S3,two cases wih S2,difference between the effects of posterior division of C7 transfering and the whole C7 transfering was not significant(P>0.05);recovery of two point discrimination in the donor finger pulps by posterior division of C7 transfering was higher but the difference was not significant(P>0.05). 4 cases presented dyskinesia in contralateral limbs.And the follow-up six months after operation showed:functional recovery M5- was achieved in two cases for the triceps,M5- in two cases for latissimus dorsi, M5- in three cases for the wrist extensors,M0 in one case for M. extensor digitorum communis and extensor pollicis longus,and the recovery was not obvious after four years of follow-ups.Conclusions:Contralateral C7 transfer is an effective procedure for functional recovery of the injured extremity with total root avulsion of brachial plexus, especially for the recovery of elbow, wrist and finger flexion.When brachial plexus surgeons consider this procedure, the possible risks of irreversible sensory abnormalities and motor deficits on the donor sides should be considered as well.