Poor electroneurography but excellent hand function 31 years after nerve repair in childhood

The Forgotten Flap: The Pedicled Trapezius Flap's Utility in Pediatric Head and Neck Reconstruction-A Systematic Review

BACKGROUND

 When free tissue transfer is precluded or undesired, the pedicled trapezius flap is a viable alternative for adults requiring complex head and neck (H&N) defect reconstruction. However, the application of this flap in pediatric reconstruction is underexplored. This systematic review aimed to describe the use of the pedicled trapezius flap and investigate its efficacy in pediatric H&N reconstruction.

METHODS

 A systematic review was performed using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Articles describing the trapezius flap for H&N reconstruction in pediatric patients were included. Patient demographics, surgical indications, wound characteristics, flap characteristics, complications, and functional outcomes were abstracted.

RESULTS

 A systematic review identified 22 articles for inclusion. Studies mainly consisted of case reports (n = 11) and case series (n = 8). In total, 67 pedicled trapezius flaps were successfully performed for H&N reconstruction in 63 patients. The most common surgical indications included burn scar contractures (n = 46, 73.0%) and chronic wounds secondary to H&N masses (n = 9, 14.3%). Defects were most commonly located in the neck (n = 28, 41.8%). The mean flap area and arc of rotation were 326.4 ± 241.7 cm2 and 157.6 ± 33.2 degrees, respectively. Most flaps were myocutaneous (n = 48, 71.6%) and based on the dorsal scapular artery (n = 32, 47.8%). Complications occurred in 10 (14.9%) flaps. The flap's survival rate was 100% (n = 67). No instances of functional donor site morbidity were reported. The mean follow-up was 2.2 ± 1.8 years.

CONCLUSION

 This systematic review demonstrated the reliability of the pedicled trapezius flap in pediatric H&N reconstruction, with a low complication rate, no reports of functional donor site morbidity, and a 100% flap survival rate. The flap's substantial surface area, bulk, and arc of rotation contribute to its efficacy in covering soft tissue defects ranging from the proximal neck to the vertex of the scalp. The pedicled trapezius flap is a viable option for pediatric H&N reconstruction.

Peripheral nerve injuries of the upper extremity in a pediatric population: outcomes and prognostic factors

Peripheral nerve injuries of the upper limb are rare in children and poorly documented. The aim of this retrospective study was to analyze long-term sensory and motor results, and to determine predictive factors for recovery after surgery. Eleven children, with a mean age at injury of 9.7 years (5-15), operated on between 2006 and 2018, were included. Sensory perception was measured on monofilament test and static 2-point discrimination test. Grip strength was measured with a dynamometer and motor strength was assessed on the Medical Research Council scale. Quality of life was assessed on QuickDASH. The injury involved the radial (n = 1), median (n = 9), or combined median and ulnar (n = 1) nerves and was repaired by primary direct suture (n = 11). The mechanism involved glass laceration (n = 10) or a road accident (n = 1). The dominant limb was involved in 7 cases. At a mean 7.7 years' follow-up, touch sensitivity was normal or slightly deficient on monofilament test. Discrimination test was normal or adequate. Strength was complete in 10 patients. Mean QuickDASH score was 5.99 (range, 0-18.18). There was no significant difference in sensory or motor recovery according to partial or complete lesion or to injury location. There was better sensory recovery in children <12 years (p < 0.05). Sensory prognosis was also better in the absence of associated lesions (p < 0.05). Sensory, motor and functional results after surgical treatment of peripheral nerve injuries of the upper limb in children were globally satisfactory. Sensory recovery was better at an early age and in the absence of associated lesions. LEVEL OF EVIDENCE: IV.

Sensory Neurotization of the Ulnar Nerve, Surgical Techniques and Functional Outcomes: A Review

When ulnar nerve lesions happen above the wrist level, sensation recovery after acute repair or nerve grafting is often challenging. Distal sensory nerve transfers may be an option for overcoming these sequelae. However, little data has been published on this topic. This study aims to review the surgical procedures currently proposed, along with their functional results. Six donor nerves have been described at the wrist level: the palmar branch of the median nerve, the cutaneous branch of the median nerve to the palm with or without fascicles of the ulnar digital nerve of the index finger, the posterior interosseous nerve, the third palmar digital nerve, the radial branch of the superficial radial nerve, the median nerve, and the fascicule for the third web space. Three donor nerves have been reported at the hand level: the ulnar digital nerves of the index, and the radial or ulnar digital nerves of the long finger. Three target sites were used: the superficial branch of the ulnar nerve, the dorsal branch of the ulnar nerve, and the ulnar digital branch of the fifth digit. All the technical points have been illustrated with anatomical dissection pictures. After assessing sensory recovery using the British Medical Research Council scale, a majority of excellent recoveries scaled S3+ or S4 have been reported in the targeted territory for each technique.

Mesenchymal stem cell treatment for peripheral nerve injury: a narrative review

Peripheral nerve injuries occur as the result of sudden trauma and lead to reduced quality of life. The peripheral nervous system has an inherent capability to regenerate axons. However, peripheral nerve regeneration following injury is generally slow and incomplete that results in poor functional outcomes such as muscle atrophy. Although conventional surgical procedures for peripheral nerve injuries present many benefits, there are still several limitations including scarring, difficult accessibility to donor nerve, neuroma formation and a need to sacrifice the autologous nerve. For many years, other therapeutic approaches for peripheral nerve injuries have been explored, the most notable being the replacement of Schwann cells, the glial cells responsible for clearing out debris from the site of injury. Introducing cultured Schwann cells to the injured sites showed great benefits in promoting axonal regeneration and functional recovery. However, there are limited sources of Schwann cells for extraction and difficulties in culturing Schwann cells in vitro. Therefore, novel therapeutic avenues that offer maximum benefits for the treatment of peripheral nerve injuries should be investigated. This review focused on strategies using mesenchymal stem cells to promote peripheral nerve regeneration including exosomes of mesenchymal stem cells, nerve engineering using the nerve guidance conduits containing mesenchymal stem cells, and genetically engineered mesenchymal stem cells. We present the current progress of mesenchymal stem cell treatment of peripheral nerve injuries.

Cold intolerance and neuropathic pain after peripheral nerve injury in upper extremity

Cold intolerance and pain can be a substantial problem in patients with peripheral nerve injury. We aimed at investigating the relationships among sensory recovery, cold intolerance, and neuropathic pain in patients affected by upper limb peripheral nerve injury (Sunderland type V) treated with microsurgical repair, followed by early sensory re-education. In a cross-sectional clinical study, 100 patients (male/female 81/19; age 40.5 ± 14.8 years and follow-up 17 ± 5 months, mean ± SD), with microsurgical nerve repair and reconstruction in the upper extremity and subsequent early sensory re-education, were evaluated, using Cold Intolerance Symptoms Severity questionnaire-Italian version (CISS-it, cut-off pathology >30/100 points), CISS questionnaire-12 item version (CISS-12, 0-46 points-grouping: healthy that means no cold intolerance [0-14], mild [15-24], moderate [25-34], severe [35-42], very severe [43-46] cold intolerance), probability of neuropathic pain (DouleurNeuropathique-4; [DN4] 4/10), deep and superficial sensibility, tactile threshold (monofilaments), and two-point discrimination (cutoff S2; Medical Research Council scale for sensory function; [MRC-scale]). A high CISS score is associated with possible neuropathic pain (DN4 ≥ 4). Both a low CISS-it score (ie, < 30) and DN4 < 4 is associated with good sensory recovery (MRC ≥ 2). In conclusion patients affected by upper limb peripheral nerve injuries with higher CISS scores more often suffer from cold intolerance and neuropathic pain, and the better their sensory recovery is, the less likely they are to suffer from cold intolerance and neuropathic pain.

Cortical Plasticity in Rehabilitation for Upper Extremity Peripheral Nerve Injury: A Scoping Review

IMPORTANCE

Poor outcomes after upper extremity peripheral nerve injury (PNI) may arise, in part, from the challenges and complexities of cortical plasticity. Occupational therapy practitioners need to understand how the brain changes after peripheral injury and how principles of cortical plasticity can be applied to improve rehabilitation for clients with PNI.

OBJECTIVE

To identify the mechanisms of cortical plasticity after PNI and describe how cortical plasticity can contribute to rehabilitation.

DATA SOURCES

PubMed and Embase (1900-2017) were searched for articles that addressed either (1) the relationship between PNI and cortical plasticity or (2) rehabilitative interventions based on cortical plastic changes after PNI.

STUDY SELECTION AND DATA COLLECTIO

: PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines were followed. Articles were selected if they addressed all of the following concepts: human PNI, cortical plasticity, and rehabilitation. Phantom limb pain and sensation were excluded.

FINDINGS

Sixty-three articles met the study criteria. The most common evidence level was Level V (46%). We identified four commonly studied mechanisms of cortical plasticity after PNI and the functional implications for each. We found seven rehabilitative interventions based on cortical plasticity: traditional sensory reeducation, activity-based sensory reeducation, selective deafferentation, cross-modal sensory substitution, mirror therapy, mental motor imagery, and action observation with simultaneous peripheral nerve stimulation.

CONCLUSION AND RELEVANCE

The seven interventions ranged from theoretically well justified (traditional and activity-based sensory reeducation) to unjustified (selective deafferentation). Overall, articles were heterogeneous and of low quality, and future research should prioritize randomized controlled trials for specific neuropathies, interventions, or cortical plasticity mechanisms.

WHAT THIS ARTICLE ADDS

This article reviews current knowledge about how the brain changes after PNI and how occupational therapy practitioners can take advantage of those changes for rehabilitation.

The plasticity of the corticospinal tract in children with obstetric brachial plexus palsy after Botulinum Toxin A treatment

Botulinum neurotoxin A (BTX-A) intervention has long-term benefits for children with obstetric brachial plexus palsy (OBPP). Although cortical plasticity has been widely studied, plasticity in white matter has not received as much attention. Here, six children with OBPP underwent functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI) before and 6 months after BTX-A treatment. Surface electromyography (EMG) was recorded. The aim was to investigate changes in the corticospinal tract (CST) as an example longitudinal observation of white matter plasticity. Deterministic fiber tracking with a Fiber Assignment by Continuous Tracking algorithm was used to reconstruct the CST. Fiber tracts passing through a region of interest (ROI) in the posterior limb of the internal capsule and a target ROI in the upper-limb representation of M1 (defined by task-related fMRI) were selected as the CST. Motor performances were improved while EMG showed no significant difference 6 months after the treatment. We observed a significant increase in mean fractional anisotropy and a significant decrease in fiber number after treatment. We analyzed the correlations between DTI metrics and clinical motor assessments. Although the correlation results were not statistically significant, they support the notion that BTX-A treatment causes white matter plasticity and has a positive long-term outcome. Peripheral deafferentation may lead to altered information flow, resulting in the positive adaptation of white matter. This study provides novel insight into cerebral plasticity following peripheral nerve regeneration and indicates that a combination of relatively non-invasive therapies can accelerate plasticity of sensorimotor circuits and promote functional recovery in OBPP.

Sensation, mechanoreceptor, and nerve fiber function after nerve regeneration

OBJECTIVE

Sensation is essential for recovery after peripheral nerve injury. However, the relationship between sensory modalities and function of regenerated fibers is uncertain. We have investigated the relationships between touch threshold, tactile gnosis, and mechanoreceptor and sensory fiber function after nerve regeneration.

METHODS

Twenty-one median or ulnar nerve lesions were repaired by a collagen nerve conduit or direct suture. Quantitative sensory hand function and sensory conduction studies by near-nerve technique, including tactile stimulation of mechanoreceptors, were followed for 2 years, and results were compared to noninjured hands.

RESULTS

At both repair methods, touch thresholds at the finger tips recovered to 81 ± 3% and tactile gnosis only to 20 ± 4% (p < 0.001) of control. The sensory nerve action potentials (SNAPs) remained dispersed and areas recovered to 23 ± 2% and the amplitudes only to 7 ± 1% (P < 0.001). The areas of SNAPs after tactile stimulation recovered to 61 ± 11% and remained slowed. Touch sensation correlated with SNAP areas (p < 0.005) and was negatively related to the prolongation of tactile latencies (p < 0.01); tactile gnosis was not related to electrophysiological parameters.

INTERPRETATION

The recovered function of regenerated peripheral nerve fibers and reinnervated mechanoreceptors may differentially influence recovery of sensory modalities. Touch was affected by the number and function of regenerated fibers and mechanoreceptors. In contrast, tactile gnosis depends on the input and plasticity of the central nervous system (CNS), which may explain the absence of a direct relation between electrophysiological parameters and poor recovery. Dispersed maturation of sensory nerve fibers with desynchronized inputs to the CNS also contributes to the poor recovery of tactile gnosis. Ann Neurol 2017. Ann Neurol 2017;82:940-950.

Age does not affect the outcome after digital nerve repair in children - A retrospective long term follow up

BACKGROUND

Digital nerve injuries in children are not common, but they are considered to have an excellent prognosis, compared to adults, after nerve injury and repair. In studies including both children and adults age have been found to have an effect on outcome after nerve repair.

METHODS

We investigated in a retrospective follow up study the long-time result after digital nerve injury and repair in children, 1-16 years of age (n = 38), and evaluate if age influences outcome. A group with young children, 1-10 years of age (n = 18), was compared with a group with older children, 11-16 years of age (n = 20). A clinical evaluation to evaluate sensation and grip strength was performed and questionnaires were used [Disability of the Arm, Shoulder and Hand (DASH), Cold Sensitivity Severity Scale (CISS), VAS-function and VAS-cosmetic] in median 40 months (range 12-131 months) after the injury and repair.

RESULTS

All patient regained normal sensation. No correlations between age and monofilaments were found. Twenty children (52%) reported some problems with cold intolerance (i.e. CISS), but no other abnormal disability was found (i.e. DASH, VAS); again with no differences between the two groups.

CONCLUSIONS

Children have an excellent long-term recovery after a digital nerve repair and without any influence of age.

Cortical plasticity in patients with median nerve lesions studied with MEG

We have previously shown age- and time-dependent effects on brain activity in the primary somatosensory cortex (SI), in a functional magnetic resonance imaging (fMRI) study of patients with median nerve injury. Whereas fMRI measures the hemodynamic changes in response to increased neural activity, magnetoencephalography (MEG) offers a more concise way of examining the evoked response, with superior temporal resolution. We therefore wanted to combine these imaging techniques to gain additional knowledge of the plasticity processes in response to median nerve injury. Nine patients with median nerve trauma at the wrist were examined with MEG. The N1 and P1 responses at stimulation of the injured median nerve at the wrist were lower in amplitude compared to the healthy side (p < .04). Ulnar nerve stimulation of the injured hand resulted in larger N1 amplitude (p < .04). The amplitude and latency of the response did not correlate with the sensory discrimination ability. There was no correlation between N1 amplitude and size of cortical activation in fMRI. There was no significant difference in N1 latency between the injured and healthy median nerve. N1 latency correlated positively with age in both the median and ulnar nerve, and in both the injured and the healthy hand (p < .02 or p < .001). It is concluded that conduction failure in the injured segment of the median nerve decreases the amplitude of the MEG response. Disinhibition of neighboring cortical areas may explain the increased MEG response amplitude to ulnar nerve stimulation. This can be interpreted as a sign of brain plasticity.

G-CSF prevents caspase 3 activation in Schwann cells after sciatic nerve transection, but does not improve nerve regeneration

Exogenous granulocyte-colony stimulating factor (G-CSF) has emerged as a drug candidate for improving the outcome after peripheral nerve injuries. We raised the question if exogenous G-CSF can improve nerve regeneration following a clinically relevant model - nerve transection and repair - in healthy and diabetic rats. In short-term experiments, distance of axonal regeneration and extent of injury-induced Schwann cell death was quantified by staining for neurofilaments and cleaved caspase 3, respectively, seven days after repair. There was no difference in axonal outgrowth between G-CSF-treated and non-treated rats, regardless if healthy Wistar or diabetic Goto-Kakizaki (GK) rats were examined. However, G-CSF treatment caused a significant 13% decrease of cleaved caspase 3-positive Schwann cells at the lesion site in healthy rats, but only a trend in diabetic rats. In the distal nerve segments of healthy rats a similar trend was observed. In long-term experiments of healthy rats, regeneration outcome was evaluated at 90days after repair by presence of neurofilaments, wet weight of gastrocnemius muscle, and perception of touch (von Frey monofilament testing weekly). The presence of neurofilaments distal to the suture line was similar in G-CSF-treated and non-treated rats. The weight ratio of ipsi-over contralateral gastrocnemius muscles, and perception of touch at any time point, were likewise not affected by G-CSF treatment. In addition, the inflammatory response in short- and long-term experiments was studied by analyzing ED1 stainable macrophages in healthy rats, but in neither case was any attenuation seen at the injury site or distal to it. G-CSF can prevent caspase 3 activation in Schwann cells in the short-term, but does not detectably affect the inflammatory response, nor improve early or late axonal outgrowth or functional recovery.

Normalized activation in the somatosensory cortex 30 years following nerve repair in children: an fMRI study

The clinical outcome following a peripheral nerve injury in the upper extremity is generally better in young children than in teenagers and in adults, but the mechanism behind this difference is unknown. In 28 patients with a complete median nerve injury sustained at the ages of 1-13 years (n = 13) and 14-20 years (n = 15), the cortical activation during tactile finger stimulation of the injured and healthy hands was monitored at a median time since injury of 28 years using functional magnetic resonance imaging (fMRI) at 3 Tesla. The results from the fMRI were compared with the clinical outcome and electroneurography. The cortical activation pattern following sensory stimulation of the median nerve-innervated fingers was dependent on the patient's age at injury. Those injured at a young age (1-13 years) had an activation pattern similar to that of healthy controls. Furthermore, they showed a clinical outcome significantly superior (P = 0.001) to the outcome in subjects injured at a later age; however, electroneurographical parameters did not differ between the groups. In subjects injured at age 14-20 years, a more extended activation of the contralateral hemisphere was seen in general. Interestingly, these patients also displayed changes in the ipsilateral hemisphere where a reduced inhibition of somatosensory areas was seen. This loss of ipsilateral inhibition correlated to increasing age at injury as well as to poor recovery of sensory functions in the hand. In conclusion, cerebral changes in both brain hemispheres may explain differences in clinical outcome following a median nerve injury in childhood or adolescence.

Differential recovery of touch thresholds and discriminative touch following nerve repair with focus on time dynamics

Introduction

The purpose of this secondary analysis of pooled data from two randomised controlled trials was to explore the differential rate of recovery of sensory and motor functions over time following repair of median or ulnar nerve.

Methods

Recovery over two years following median or ulnar nerve repair at wrist level using the Rosen score was analysed in 67 patients.

Results

Within the sensory domain of the Rosen score, a substantial gap was observed between recovery of touch thresholds and discriminative touch. Within the motor domain, manual muscle strength and grip strength showed a closer and more parallel recovery rate.

Conclusion

The differential recovery rates in touch thresholds and discriminative touch after a peripheral nerve injury are likely due to neurobiological factors that cannot be influenced by surgical interventions. However, new knowledge about brain plasticity opens up the possibility that this differential recovery may diminish through the use of revised rehabilitation programs focused on the use of guided plasticity, and the timing of onset of sensory re-learning.

Repair of the Peripheral Nerve-Remyelination that Works

In this review we summarize the events known to occur after an injury in the peripheral nervous system. We have focused on the Schwann cells, as they are the most important cells for the repair process and facilitate axonal outgrowth. The environment created by this cell type is essential for the outcome of the repair process. The review starts with a description of the current state of knowledge about the initial events after injury, followed by Wallerian degeneration, and subsequent regeneration. The importance of surgical repair, carried out as soon as possible to increase the chances of a good outcome, is emphasized throughout the review. The review concludes by describing the target re-innervation, which today is one of the most serious problems for nerve regeneration. It is clear, compiling this data, that even though regeneration of the peripheral nervous system is possible, more research in this area is needed in order to perfect the outcome.