Shaonan Hu

Sensorimotor cortical changes assessed with resting-state fMRI following total brachial plexus root avulsion

Objective Peripheral nerve injury can induce immediate and long-standing remodelling of the brain cortex, which may affect outcomes of nerve repair. This study examined changes of corresponding cortical representations in patients with brachial plexus injuries. Methods Resting-state fMRI was acquired for 13 adult patients with total brachial plexus root avulsion, three of whom underwent second scans 7 or 8 months later. The time of examination ranged from 1 to 16 months after injuries. Nine healthy adults were enrolled as control. Seed-based functional connectivity was performed for all subjects. Results For nine patients whose first fMRI was performed from 1 to 4 months after brachial plexus injuries, images showed that their cortical maps of sensorimotor areas corresponding to the hand and arm in the hemisphere contralateral to the injured side had much weaker correlation with the supplementary motor area (SMA) than those ipsilateral to the injured side. Symmetrical maps of bilateral cortical sensorimotor areas corresponding to the hand and arm were observed in other four cases with fMRI tested from 7 to 16 months after injuries. For three of the nine patients with asymmetrical cortical representations, second scans indicated symmetric results or even stronger correlation with SMA in the cerebral cortex contralateral to the injured side. Conclusions Total brachial plexus root avulsion causes cortical representations of the brachial plexus to undergo a change from an inactive to an active state. This implies that peripheral deafferentation after brachial plexus injuries will induce corresponding cortical representations to be occupied by adjacent non-deafferented cortical territories.

Histopathologic study of the neuroma-in-continuity in obstetric brachial plexus palsy.

Background: Operative treatment of traction lesions in obstetric brachial plexus palsy is still controversial. The authors analyzed the histopathology of neuroma-in-continuity of the upper trunk by study of the resected neuroma. Methods: The neuroma-in-continuity of the upper trunk was studied histopathologically in 28 children with Erb palsy who had undergone resection of the neuroma and nerve reconstruction of the plexus at the age of 3 to 11 months. The authors recorded the distribution of myelinated motor nerve fibers and the proportions of collagen and regenerating nerve fibers traveling the neuroma, analyzed the relationship between the percentage of nerve fibers across the neuroma and findings of intraoperative neurophysiologic investigations and the patients age at surgery, and compared the number of nerve fibers in C5 and C6 proximal to the neuroma with that in their normal counterparts. Results: In the central segment of the neuroma, the structure of the upper trunk was replaced by copious collagen and sporadic nerve fibers wrapped by an undeveloped myelin sheath, and the percentage of collagen was statistically greater than that of the normal upper trunk. The mean percentage of regenerating nerve fibers across the neuroma was 41.83 percent (95 percent confidence interval, 38.69 to 44.69 percent) and this was not statistically correlated with the outcome of intraoperative neurophysiologic investigations or the patients age at surgery. The number of nerve fibers was statistically less in C5 and C6 proximal to the neuroma than in their normal counterparts. Conclusions: The nerve structure of the neuroma-in-continuity is substantially damaged in obstetric brachial plexus palsy. Its resection followed by nerve reconstruction of the plexus is favored.

Results of intercostal nerve transfer to the musculocutaneous nerve in brachial plexus birth palsy.

Background: Intercostal nerve (ICN) transfer has been one of the main extraplexal nerve transfers in treating brachial plexus root avulsion. This retrospective study evaluated results of ICN transfer for reconstruction of the musculocutaneous nerve (MCN) in brachial plexus birth palsy (BPBP). Methods: Eighteen boys and 6 girls with BPBP, who had avulsion of at least 2 spinal nerves of the plexus, underwent ICN transfer for reconstruction of MCN, from March 2003 to October 2005. The brachial plexus lesion was diagnosed by clinical assessment, surgical exploration, and intraoperative neurophysiological investigations. The age at surgery ranged from 3 to 11 months of life, with a mean of 5 months. Two intercostals were used for one, 3 intercostals for 9, and 4 intercostals for 14 patients. The intercostals were transferred to MCN in 12 and to the anterior division of the upper trunk in the other 12 cases. Results: Twenty-four children were followed up for 24 to 79 months, with an average of 53 months. No complications were found in the respiratory system. Of 14 transfers with 4 intercostals, biceps gained M4 strength in 8, M3 in 4, and M2 in 2. Of 9 transfers with 3 intercostals, biceps obtained M4 strength in 8 and M3 in 1. One transfer with 2 intercostals got M4 strength of biceps. Twelve patients whose intercostals were transferred to MCN, gained M4 strength of biceps in 11 and M3 in 1, whereas the other 12 patients with intercostals transferred to anterior division of the upper trunk, obtained M4 strength of biceps in 6, M3 in 4, and M2 in 2. The rate of M3 strength or more was 92% and that of M4 was 71%. Conclusions: ICN transfer is a safe and reliable procedure for reconstruction of the MCN in BPBP. There seems to be no difference of effects between transfers with 3 and those with 4 intercostals. The transferred nerves should be coapted to MCN, rather than a more proximal portion of the plexus. Level of Evidence: Level III: retrospective comparative study.

Optimal time-point for neural stem cell transplantation to delay denervated skeletal muscle atrophy.

Transplantation of neural stem cells (NSCs) is a promising treatment to delay denervated skeletal muscle atrophy; however, the optimal time‐point between peripheral nerve injury and NSC transplantation needs to be determined.

Combined application of neutrophin-3 gene and neural stem cells is ameliorative to delay of denervated skeletal muscular atrophy after tibial nerve transection in rats.

Examination of the therapeutic efficacy of neural stem cells (NSCs) has recently become the focus of much investigation. In this study we present an insight of the effects of combined application with neurotrophin-3 (NT-3) and NSCs that derived from rat embryo spinal cord on delaying denervated skeletal muscular atrophy after tibial nerve was severed. NT-3 gene was amplified by PCR and subcloned into lentiviral vector pWPXL-MOD to construct a lentiviral expression vector pWPXL-MOD-NT-3. A positive clone expressing NT-3 (named NSCs-NT-3) was obtained and used for differentiation in vitro and transplantation. Sixty adult rats, whose tibial nerves were sectioned, were divided into two groups: one grafted with NSCs-NT-3 (experimental group, n = 30) and the other with NSCs transfected by pWPXL-MOD (control group, n = 30). The cell survival and differentiation, NT-3 gene expression, and effect of delaying denervated skeletal muscular atrophy were examined through immunohistostaining, RT-PCR, Western blot, electrophysiological analysis, and mean cross-sectional area (CSA) of gastrocnemius, respectively. The results show that the NT-3 gene, which is comprised of 777 bp, was cloned and significantly different expression were detected between NSCs and NSCs-NT-3 in vitro. Quantitative analysis of the choline acetyltransferase (ChAT) immunopositive cells revealed a significant increase in experimental group compared to the control group 4 weeks after implantation (p < 0.01). Twelve weeks after transplantation, the ChAT immunopositive cells were detected near the engrafted region only in experimental group. Furthermore, the effect in delaying denervated skeletal muscular atrophy is indicated in the EMG examination and mean CSA of gastrocnemius. These findings suggest that the neural stem cells expressing NT-3 endogenously would be a better graft candidate for the delay of denervated skeletal muscular atrophy.

Delayed toe transplantation : Experimental study and clinical application

&NA; Delay of the operation in toe transplantation was performed with circulatory crisis, and 100 percent survival of the transplants was achieved. In 10 cases of toe transplantation in which circulatory crisis occurred, the operation was delayed. The vascular pedicle was divided, and the toe was transferred 17 to 21 hours after the donor toe was dissected. To investigate the mechanism of delayed toe transplantation, experiments in rabbits were carried out. In 36 rabbits, the hind limbs were severed except for the vascular pedicle. The endothelin content and nitric oxide content of the tissues in the hind limb and the arterial wall were tested in postoperative intervals of 4, 8, 16, 24, and 48 hours, respectively. The results showed that in 10 cases of delayed toe transplantation, all toes survived. As for the results of the experiment, there was significant increase of endothelin content and decrease of nitric oxide content in the local tissues and the arterial wall 4 to 8 hours after the operation. In postoperative 16 to 24 hours, endothelin content returned to normal level, and nitric oxide content increased remarkably. It is concluded that delayed pedicle division and toe transfer is an effective method in toe transplantation with vascular variations and circulatory crisis. The mechanism is related to the endothelin and nitric oxide content in the local tissue and the arterial wall. The indications for delayed toe transfer are also discussed. (Plast. Reconstr. Surg. 105: 1675, 2000.)

Dual Nerve Transfers for Restoration of Shoulder Function After Brachial Plexus Avulsion Injury

AbstractThe purpose of this study was to investigate the effectiveness of shoulder function restoration by dual nerve transfers, spinal accessory nerve to the suprascapular nerve and 2 intercostal nerves to the anterior branch of the axillary nerve, in patients with shoulder paralysis that resulted from brachial plexus avulsion injury. It was a retrospective analysis to assess the impact of a variety of factors on reanimation of shoulder functions with dual nerve transfers. A total of 19 patients were included in this study. Most of these patients sustained avulsions of C5, C6, and C7 nerve roots (16 patients). Three of them had avulsions of C5 and C6 roots only. Through a posterior approach, direct coaptation of the intercostal nerves and the anterior branch of the axillary nerve was performed, along with accessory nerve transfer to the suprascapular nerve. Satisfactory shoulder function recovery (93.83° of shoulder abduction and 54.00° of external rotation on average) was achieved after a 62-month follow-up. This dual nerve transfer procedure provided us with a reliable and effective method for shoulder function reconstruction after brachial plexus root avulsion, especially C5/C6/C7 avulsion. The level of evidence is therapeutic IV.

Anatomic study of the intercostal nerve transfer to the suprascapular nerve and a case report

The purpose of this study was to investigate the anatomical basis of intercostal nerve transfer to the suprascapular nerve and provide a case report. Thoracic walls of 30 embalmed human cadavers were used to investigate the anatomical feasibility for neurotization of the suprascapular nerve with intercostal nerves in brachial plexus root avulsions. We found that the 3rd and 4th intercostal nerves could be transferred to the suprascapular nerve without a nerve graft. Based on the anatomical study, the 3rd and 4th intercostal nerves were transferred to the suprascapular nerve via the deltopectoral approach in a 42-year-old man who had had C5-7 root avulsions and partial injury of C8, T1 of the right brachial plexus. Thirty-two months postoperatively, the patient gained 30° of shoulder abduction and 45° of external rotation. This procedure provided us with a reliable and convenient method for shoulder function reconstruction after brachial plexus root avulsion accompanied with spinal accessory nerve injury. It can also be used when the accessory nerve is intact but needs to be preserved for better shoulder stability or possible future trapezius transfer.

Functional reconstruction of the irreparable upper trunk defect of the brachial plexus--a case report.

We report a successful application of Oberlins procedure combined with transfer of trapezius and latissimus dorsi with the teres major for reconstruction of elbow flexion as well as abduction and external rotation of the shoulder to a ten-year-old patient, who had a long defect of the left brachial plexus upper trunk caused by resection of the plexiform neuroma.