Objective To investigate the quantity and distribution of motor fiber of rat’s C7 nerve root. Methods Motor fiber quantity and section area in the main nerves of the upper extremity and the fascicles of C7 in 30 SD rats were analyzed.Results Fascicles and certain amount (207) of motor fibers from the anterior division of C7 were distributed to musculocutaneous nerve and median nerve, the orientation of these fibers were not clear. The ones (323) from posterior division were to the axillary, radial, and dorsal thoracic nerves, thus the orientation of these fascicles was relatively definite. Conclusion Thedistribution of the motor fibers and fascicles in the divisions of C7 in rat is similar to human beings, so rat is a relatively good model for the study of selective C7 nerve root transfer.
Objective To explore the changes of morphology and ventricornual motor neuronsin SD rats’ ventral horn of spinal cord after radiated as the therapy protocol for breast cancer, to discover the rule of radiationinduced injury of brachialplexus, and also if there exits the reversible conversion in neurons. Methods Twenty SD rats were selected. The left side of the rats was used as the radiation side, and the right side as the control side. The RIBPI animal models were established by divideddose of radiation. Using 2 Gy/time and 5 times/week, a total administered dose reached 30 Gy after 3 weeks. The behaviour of the rats was observed after radiation. At 3, 5, 7 and 9 weeks after the last radiation (n=4), the wet weights of biceps brachii muscle, upperlimb circumference and compound action potential were examined; the pathological changes of biceps brachiimuscle, the morphological changes, counts of the motor neurons in ventral horn and axons of bilateral spinal cord were observed by HE staining, argentums staining and toluidine blue staining. Results The rats showed lameness and a “claw hand” 3 weeks after radiation. Compared with control side, thewet weights of biceps brachii muscle and upperlimb circumference were significantly reduced, meanwhile, the compound action potential significantly decreased, and its latent period was also significantly prolonged 3, 5, 7 and 9 weeks (Plt;0.05). The histological observation: Musculocutaneous nerve showed decreased medullated fibers, heterogeneous ditribution and decreased density, thin myelin sheath, damaged nerve structure and collagen hyperplasia; biceps brachii muscle showed degeneration, fiber breakage and inflammatory cell infiltration; The account of motor neurons in ventral horn was significantly decreased in the radiation side with time extending, the sign of cell death, such as, the neurons crimple, and karyolysis were observed(Plt;0.05). Conclusion Large dose of X-ray can inducedbrachial plexus injury, and the lameness, a “claw hand”, biceps brachii muscle atrophy and the compound action potential abnormality. The account of motor neurons in ventral horn was significantly decreased. The motor neurons showed oxonal degeneration and myelinec degeration.
OBJECTIVE To observe the ultrastructural changes and number of satellite cells in different muscles with different denervation interval and investigate the mechanism of denervation atrophy. METHODS Muscles of different denervation interval were harvested, which were 6 biceps brachii and 6 abductor digiti minimi. The ultrastructure of the samples were observed under transmission electron microscope. The number of nucleus and satellite cells were counted to calculate the percentage content of satellite cells. RESULTS In early stage of denervation, the myofilament and sarcomere of the majority were well oriented. The nucleoli of some muscle cell nucleus were enlarged and pale. Vacuolarization was also seen in some mitochondria. There was no obvious proliferation of collagen fiber around myofibers. After denervation of half a year, rupture and disorientation of myofilament was seen. The nucleus became smaller, dark stained, and some of them were condensed. There was proliferation of fibroblasts, adipose cells and collagen fibers around myofibers. Motor endplate was not recognized one year after denervation. In the early stage of denervation, satellite cell percentage of the two muscles was relatively high. It then declined with time. One year after denervation, satellite cells were scarcely detected. Comparison of the curves for satellite cell declination in two muscles revealed that the declination of the abductor digiti minimi was faster than that of biceps brachii. Decrease of the former started 3 months after denervation, while the latter started after 6 months. CONCLUSION Disappearing of motor endplate and proliferation of collagen fibers are main factors that affect the treatment outcome in late cases. Decrease of satellite cell number is another cause. The correlation of less satellite cell in abductor digiti minimi and poorer recovery of hand intrinsic muscles indicates that increment of satellite cells in long-term denervated muscles may be one of the effective measures to improve treatment outcome.
Objective To evaluate the feasibil ity of direct anastomosis in the rat model of the brachial plexus extravertebral foramen nerve root division of C5-7. Methods Forty-eight SD rats (male or female) aging 4-6 months and weighing 250-300 g were selected to make the model of extravertebral foramen nerve root division of C5-7. The left C5-7 nerve roots, as the experimental sides, were separated to the brachial plexus nerve trunk and the transected roots were sutured to theproximal stump immediately after cutting off the brachial plexus extravertebral foramen nerve root division. The right C5-7nerve roots, as the control sides, received no operation. The general condition of rats after operation was observed. The gross observation, the histological observation and BDA nerve tracing technology were adopted to observe the wet weight of musculus biceps brachii, the cross section of biceps brachii and the spinal cord and distal nerve trunk at 3 weeks, 3 months and 6 months after operation. Results All rats survived well after operation. Claudication and unfold claw reflex were observed in the experimental sides, and the unfold claw reflex disappeared 3 months later. Comparatively, the control sides were normal. Nerve adhesion aggravated gradually and the neural stems were shriveled within 6 months after operation in the experimental sides. Comparatively, the control sides were normal. The wet weight of biceps brachii in the experimental sides and the control sides at 3 weeks, 3 months and 6 months after operation was (0.28 ± 0.12), (1.37 ± 0.33), (0.58 ± 0.10), (1.36 ± 0.35), (1.39 ± 0.31), (1.37 ± 0.38) g, respectively, indicating significant differences between two sides at 3 weeks and 3 months (P lt; 0.05), but no significant difference at 6 months (P gt; 0.05). The modified Marsland and the LFB staining of spinal cord and superior trunk of brachial plexus showed that the number of neurons, cell nuclear and Nissl body decreased and cell bodies changed from swell ing to shrinkage, dyeing nerve fibers increased, neural axone was thin and myel in sheath was sl ightly stained at each time point in experimental side. The number of motor neurons in cornu anterius medullae spinal is in the experimental side was 84.5% ± 3.2%, 74.4% ± 4.5%, 73.7% ± 3.8% of that in the control side at each time point, respectively. HE staining of biceps brachii detected thatthe muscle denaturation was very serious at 3 months after operation and then recovered. Neural tracing used BDA showed that the closer to the proximal of nerve trunk, the more obviously stained it was of myel in sheath and the more massive of axon at 6 months after operation. And there was almost no myel in and axon stained in musculocutaneous nerve. Conclusion In the rat model of brachial plexus extravertebral foramen nerve root division, the motoneuron in cornu anterius medullae spinal is necrosis rate reaches 20%-30%, and most of the residual neurons are pathologic. The regenerated fibers manifest as insufficient dynamic power and incomplete development, making no sense for the recovery of end organ function. Therefore, the exact mechanism of the recovery of biceps brachial muscle demands further study.
OBJECTIVE: To investigate the variation of neurotrophic factors expression in spinal cord and muscle after root avulsion of brachial plexus. METHODS: Forty-eight Wistar rats were involved in this study and according to the observing time in 1st day, 1st week, 4th week, 8th week, and 12th week after avulsion, and the control, were divided into 6 groups. By immunohistochemical and hybridization in situ assays, the expression of nerve growth factor (NGF) on muscle, basic fibroblast growth factor(bFGF) and its mRNA on the neurons of corresponding spinal cord was detected. Computer image analysis system was used to calculate the result. RESULTS: After the root avulsion of brachial plexus occurred, expression of NGF increased and reached to the peak at the 1st day. It subsided subsequently but was still higher than normal control until the 12th week. While expression of bFGF and its mRNA increased in the neurons of spinal cord and reached to the peak at the 1st week. Then it dropped down and at the 12th week it turned lower than normal control. CONCLUSION: After root avulsion of brachial plexus, neurotrophic factors expression increase on target muscle and neurons of corresponding spinal cord. It maybe the autoregulation and may protect neuron and improve nerve regeneration.
Objective To study and compare the effect of end-to-end and end-to-side neurorrhaphy between the reci pient’s musculocutaneous nerve and the donor’s ulnar nerve, and to observe the regeneration of peri pheral nerve and muscle refection. Methods Sixty male SD rats (weighing 200-250 g) were randomized into 2 groups (n=30 per group), and made the musculocutaneous nerve injury model. In group A, the donor’s nerve was transected for end-to-end neurorrhaphy.In group B, an epineurial window was exposed and the distal end of the muscle branch of musculocutaneous nerve was sutured to the side of the ulnar nerve. Electromyography was performed, biceps wet weight ratio, muscle fiber cross-sectional area, and count of myel inated nerve fiber (CMF) were measured at 4 and 12 weeks postoperatively. The behavior changes of the rats were observed. Results At 4 weeks, the nerve conduction velocity (NCV) and the latency ampl itude (AMP) of group A were significantly higher than those of group B (P lt; 0.05); at 12 weeks, there was no significant difference in the NCV and AMP between groups A and B (P gt; 0.05). At 4 and 8 weeks, there was no significant difference in biceps wet weight ratio and muscle fiber cross-sectional area between groups A and B (P gt; 0.05). At 4 weeks, the CMF was 230.15 ± 60.25 in group A and 160.73 ± 48.77 in group B, showing significant difference (P lt; 0.05); at 12 weeks, it was 380.26 ± 10.01 in group A and 355.63 ± 28.51 in group B, showing no significant difference (P gt; 0.05). Conclusion Both end-to-end and end-to-side neurorrhaphy have consistent long-term effect in repair of brachial plexus upper trunk injury.
ObjectiveTo evaluate the methods and effectiveness of contralateral C7 nerve root and multiple nerves transfer for the treatment of brachial plexus root avulsion.
MethodsBetween June 2006 and June 2010, 23 patients with brachial plexus root avulsion were treated. There were 20 males and 3 females, aged 17 to 42 years (mean, 27.4 years). The time from injury to operation was 4 to 12 months (mean, 5.9 months). In 16 patients having no associated injury, the first stage procedure of contralateral C7 nerve root transfer and accessory nerve transfer to suprascapular nerve or phrenic nerve transfer to anterior upper trunk was performed, and the second stage procedure of the contralateral C7 nerve root transfer to median nerve and intercostal nerve transfer to axillary nerve was performed. In 4 patients having phrenic nerve and accessory nerve injuries, the first stage procedure of the contralateral C7 nerve root transfer and second stage procedure of the contralateral C7 nerve root transfer to median nerve and musculocutaneous nerve were performed. In 3 patients having hemothorax, pneumothorax, and rib fractures, the first stage procedure of the contralateral C7 nerve root transfer and accessory nerve transfer to suprascapular nerve, and the second stage procedure of the contralateral C7 nerve root transfer to median nerve and musculocutaneous nerve were performed. The British Medical Research Council (MRC) sensory grading (S0-S4) and modified muscle strength grading standard (M0-M5) were used for comprehensive assessment of limb and shoulder abduction, elbow/biceps muscle strength, flexor wrist and finger muscle strength and median nerve sensory recovery.
ResultsTwenty-three patients were followed up 3-4.5 years (mean, 3.4 years). At 3 years after operation, the shoulder abduction reached 0-82°(mean, 44°). In 16 patients having no associated injuries, the shoulder abduction was more than 30°in 13 cases, and was more than 60°in 3 cases; in 3 patients having hemothorax, pneumothorax, and rib fractures, the shoulder abduction was more than 30°; and in 4 patients having phrenic nerve and accessory nerve injuries, the shoulder abduction was 0°. The muscle strength of elbow/biceps was M3 or more than M3 in 9 cases, was M1-M2 in 8 cases, and was M0 in 6 cases; the muscle strength of flexor wrist or finger was M3 or more than M3 in 7 cases, was M1-M2 in 11 cases, and was M0 in 5 cases. Median nerve sensory recovery was S3 or more than S3 in 11 cases, was S1-S2 in 7 cases, and was S0 in 5 cases. After 3 years, affected limb had locomotor activity in 11 patients, affected limb had activities driven by the contralateral latissimus dorsi muscle contraction in 12 patients.
ConclusionContralateral C7 nerve root and multiple nerves transfer is a good method to treat brachial plexus root avulsion.
【Abstract】 Objective To investigate the feasibil ity of contralateral C7 nerve transfer via posterior spinal route fortreatment of brachial plexus root avulsion injury by anatomical study. Methods Ten cadaveric specimens of 7 men and3 women were selected, who had no obvious deformity and no tissue defect in neck neutral position. By simulating surgical exploration of brachial plexus injury, the length of contralateral C7 nerve root was elongated by dissecting its anterior and posterior divisions to the distal end, while the length of C7 nerve from the intervertebral foramen to the branching point and the length of the anterior and posterior divisions were measured. By simulating cervical posterior approach, the C7 vertebral plate and T1 spinous process were fully exposed; the hole was made near vertebral body; and the C7 nerve root lengths by posterior vertebra path to the contralateral upper trunk and lower trunk were measured. Results C7 nerve root length was (58.62 ± 8.70) mm; the length of C7 nerve root plus posterior or anterior division was (65.15 ± 9.11) mm and (70.03 ± 10.79) mm, respectively. By posterior spinal route, the distance was (72.12 ± 10.22) mm from the end of C7 nerve to the contralateral upper trunk of brachial plexus, and was (95.21 ± 12.50) mm to the contralateral lower trunk of brachial plexus. Conclusion Contralateral C7 nerve can be transferred to the contralateral side through posterior spinal route and it only needs short bridge nerve or no. The posterior spinal route can effectively prevent from neurovascular injury, so it might be the best surgery approach for the treatment of brachial plexus root avulsion injury.
The report of brachial plexus injuries following radical mastectomy in patients with breast cancer was rare even though the operation was a main measure in treating with breast cancer. Nine patients treated from Oct. 1989 to Feb.1991 were summarized. The results were not ideal.
Objective To analysis the electrophysiological dominance weight of the triceps brachii muscle/extensordigitorum communis muscle innervated by brachial plexus and to conclude its effect on the ipsilateral C7 transfer so as to offer electrophysiological data for the safety and indication of i psilateral C7 transfer. Methods From August 2007 to October 2007, 15 patients with complete brachial plexus nerve root avulsion received contralateral C7 transfer. There were 13 males and 2 females aged 18-49 years (28 years on average). Injury was caused by fall ing in 1 case, by crush in 2 cases and by traffic accident in 12 cases, involving left side in 8 cases and right side in 7 cases. The upper, middle and lower trunk of the brachial plexus were stimulated respectively, the compound muscle action potential (CMAP) at the triceps brachii muscle/extensor digitorum communis muscle was recorded, and then the electrophysiological dominance weight of the triceps brachii muscle/extensor digitorum communis muscle innervated by brachial plexus was confirmed according to the comparison of the ampl itude percentage of the CMAP by three trunks. The muscle strength of triceps brachii muscle/extensor digitorum communis muscle was evaluated and the electromyogram was taken 6 months after operation. Results All patients were followed up for 6 months. Concerning the electrophysiological dominance weight, the triceps brachii muscle was mainly innervated by uppermiddle trunk in 3 cases (20%), by middle-lower trunk in 3 cases (20%), by whole trunk in 7 cases (47%) and by middle trunk in 2 cases (13%). While the extensor digitorum communis muscle was mainly innervated by middle-lower trunk in 3 cases (20%), by whole trunk in 10 cases (67%) and by lower trunk in 2 cases (13%). Concerning the triceps brachii muscle, 2 patients got the muscle strength of 4 grade with recruitment simple phase at 1 month after operation and returned to normal at 3 month after operation, while 13 patients got the muscle strength of 5 grade with recruitment simple or mixed phase at 1 month after operation. Concerning the extensor digitorum communis muscle, the muscle strength and the recruitment phase of all 15 patients recovered to normal at 1 month after operation. Conclusion To patients with various kinds of electrophysiological dominance weight, the cutting of C7 does not substantially damage the triceps brachii muscle or extensor digitorum communis muscle, indicating that the ipsilateral C7 transfer is safe and feasible. However, it should be appl ied prudently for the patients with high dominance weight since it may result in the short-term decrease of triceps brachii muscle strength.
