Journal of Brachial Plexus and Peripheral Nerve Injury - Latest Articles

Advanced radiological work-up as an adjunct to decision in early reconstructive surgery in brachial plexus injuries

Kasim Abul-Kasim — 2010-07-08T00:00:00Z

Background: As neurophysiologic tests may not reveal the extent of brachial plexus injury at the early stage, the role of early radiological work-up has become increasingly important. The aim of the study was to evaluate the concordance between the radiological and clinical findings with the intraoperative findings in adult patients with brachial plexus injuries. Methods: Seven consecutive male patients (median age 33; range 15-61) with brachial plexus injuries, caused by motor cycle accidents in 5/7 patients, who underwent extensive radiological work-up with magnetic resonance imaging (MRI), computed tomography myelography (CT-M) or both were included in this retrospective study. A total of 34 spinal nerve roots were evaluated by neuroradiologists at two different occasions. The degree of agreement between the radiological findings of every individual nerve root and the intraoperative findings was estimated by calculation of kappa coefficient (K-value). Using the operative findings as a gold standard, the accuracy, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of the clinical findings and the radiological findings were estimated. Results: The diagnostic accuracy of radiological findings was 88 % compared with 65 % for the clinical findings. The concordance between the radiological findings and the intraoperative findings was substantial (K = 0.76) compared with only fair (K = 0.34) for the clinical findings. There were two false positive and two false negative radiological findings (sensitivity and PPV of 0.90; specificity and NPV of 0.87). Conclusions: The advanced optimized radiological work-up used showed high reliability and substantial agreement with the intraoperative findings in adult patients with brachial plexus injury.

Pharmacological evaluation of tacrolimus (FK-506) on ischemia reperfusion induced vasculatic neuropathic pain in rats

Arunachalam Muthuraman — 2010-06-07T00:00:00Z

Background: Ischemia reperfusion (I/R) is common in various pathological conditions like diabetic complication, rheumatic arthritis, necrotizing vascular occlusive disease and trauma. Methods: We have evaluated the effect of tacrolimus (1, 2 and 3 mg/kg, p.o. for 10 consecutive days) on femoral arterial ischemic reperfusion (I/R) induced neuropathic pain in rats. Behavioral parameters (i.e. hot plate, radiant heat, acetone drop, tail heat hyperalgesia, tail flick and tail cold allodynia tests) were assessed at different time intervals (i.e. 0, 1, 4, 7, 10, 13 and 16th day) and biochemical analysis in serum and tissue samples were also performed along with histopathological studies. Results: Behavioral pain assessment revealed increase in the paw and tail withdrawal threshold in tacrolimus treated groups against hyperalgesic and allodynic stimuli as compared to the sham control group. We observed a decrease in the serum nitrate and thiobarbituric acid reactive substance (TBARS) levels along with reduction in tissue myeloperoxidase (MPO) and total calcium levels, whereas, rise in tissue reduced glutathione levels in tacrolimus treated groups. However, significant results were obtained in medium and high dose treated group as compared to sham control group. Histopathological study had revealed the increase in the neuronal edema and axonal degeneration in the I/R group whereas, tacrolimus ameliorate these effects. Conclusion: Our results indicate the anti-oxidative, anti-inflammatory and calcium modulatory actions of tacrolimus. Therefore, it can be used as a therapeutic agent for the treatment of vascular inflammatory related neuropathic pain.

EGb761 protects motoneurons against avulsion-induced oxidative stress in rats

Xiao Cheng — 2010-05-24T00:00:00Z

Background: Root avulsion of the brachial plexus causes an oxidative stress reaction in the spinal cord and induces dramatic spinal motoneuron death, while EGb761 is a natural free radical cleaning agent. This study was designed to investigate the protective effects of intraperitoneally injected EGb761 against neural damage following brachial root avulsion. Methods: The effect of EGb761 on avulsion-induced motoneuron injury was studied in 26 total groups of (n) rats, treated as follows. Animals in singular number groups received EGb761(50 mg/kg.d) and those in complex number groups received normal saline solution (i.p.), serving as controls. Groups 1-8 were used for the determination of nitric oxide (NO) levels in the serum and injured spinal cord at the 5 d, 2 w, 4 w, and 6 w time points. Groups 9-16 were used for determination of constitutive nitric oxide synthase (cNOS) and inducible nitric oxide synthase (iNOS) levels in injured spinal cord at the 5 d, 2 w, 4 w, and 6 w time points. Groups 17-26 were used for determination of the number of neuronal nitric oxide synthase (nNOS)-positive and surviving motoneurons in injured C7 ventral horn at the 5 d, 2 w, 4 w, 6 w and 8 w time points. Results: Compared to control groups, the EGb761 treatment group not only had significant decreased levels of NO in serum at 2 w and 6 w after avulsion, but also had reduced levels of NO specifically in the spinal cord at 2 w, 4 w and 6 w. The cNOS activity in the spinal cord was also significant decreased at 2 w and 4 w, while the iNOS activity in injured C6-T1 spinal segments was reduced at 2 w, 4 w and 6 w. All together, the percentages of NADPH-d positive motoneurons in an injured C7 segment were down-regulated and the number of surviving motoneurons in injured C7 ventral horn was increased at 2 w, 4 w, 6 w and 8 w in treated versus untreated animals. Conclusions: Intraperitoneal administration of EGb761 after root avulsion of the brachial plexus exerted protective effects by decreasing the level of NO in spinal cord and serum and the activity of cNOS and iNOS, easing the delayed motoneurons death. EGb761 should be considered in the treatment of brachial plexus nerve injuries.

Progesterone - new therapy in mild carpal tunnel syndrome? Study design of a randomized clinical trial for local therapy

Paolo Milani — 2010-04-26T00:00:00Z

Background: Local corticosteroid injection for carpal tunnel syndrome (CTS) provides greater clinical improvement in symptoms one month after injection compared to placebo but significant symptom relief beyond one month has not been demonstrated and the relapse of symptoms is possible.Neuroprotection and myelin repair actions of the progesterone was demonstrated in vivo and in vitro study.We report the design of a randomized controlled trial for the local injection of cortisone versus progesterone in "mild" idiopathic CTS. Methods: Sixty women with age between 18 and 60 years affected by "mild" idiopathic CTS, diagnosed on the basis of clinical and electrodiagnostic tests, will be enrolled in one centre. The clinical, electrophysiological and ultasonographic findings of the patients will be evaluate at baseline, 1, 6 and 12 months after injection.The major outcome of this study is to determine whether locally-injected progesterone may be more beneficial than cortisone in CTS at clinical levels, tested with symptoms severity self-administered Boston Questionnaire and with visual analogue pain scale.Secondary outcome measures are: duration of experimental therapy; improvement of electrodiagnostic and ultrasonographic anomalies at various follow-up; comparison of the beneficial and harmful effects of the cortisone versus progesterone. Conclusion: We have designed a randomized controlled study to show the clinical effectiveness of local progesterone in the most frequent human focal peripheral mononeuropathy and to demonstrate the neuroprotective effects of the progesterone at the level of the peripheral nervous system in humans.

Stereological analysis of sciatic nerve in chickens following neonatal pinealectomy: an experimental study

Mehmet Turgut — 2010-04-21T00:00:00Z

Background: Although the injury to the peripheral nervous system is a common clinical problem, understanding of the role of melatonin in nerve degeneration and regeneration is incomplete. Methods: The current study investigated the effects of neonatal pinealectomy on the sciatic nerve microarchitecture in the chicken. The chickens were divided into two equal groups: unpinealectomized controls and pinealectomized chickens. At the end of the study, biochemical examination of 10 sciatic nerve samples from both groups was performed and a quantitative stereological evaluation of 10 animals in each group was performed. The results were compared using Mann-Whitney test. Results: In this study, the results of axon number and thickness of the myelin sheath of a nerve fiber in newly hatched pinealectomy group were higher than those in control group. Similarly, surgical pinealectomy group had significantly larger axonal cross-sectional area than the control group (p < 0.05). In addition, the average hydroxyproline content of the nerve tissue in neonatal pinealectomy group was higher than those found in control group. Our results suggest that melatonin may play a role on the morphologic features of the peripheral nerve tissue and that melatonin deficiency might be a pathophysiological mechanism in some degenerative diseases of peripheral nerves. The changes demonstrated by quantitative morphometric methods and biochemical analysis has been interpreted as a reflection of the effects of melatonin upon nerve tissue. Conclusion: In the light of these results from present animal study, changes in sciatic nerve morphometry may be indicative of neuroprotective feature of melatonin, but this suggestion need to be validated in the human setting.

Spectrum of peripheral neuropathies associated with surgical interventions; A neurophysiological assessment

Shiv Saidha — 2010-04-19T00:00:00Z

Background: We hypothesized that a wide range of surgical procedures may be complicated by neuropathies, not just in close proximity but also remote from procedural sites. The aim of this study was to classify post-operative neuropathies and the procedures associated with them. Methods: We retrospectively identified 66 patients diagnosed with post-procedure neuropathies between January 2005 and June 2008. We reviewed their referral cards and medical records for patient demographics, information on procedures, symptoms, as well as clinical and neurophysiological findings. Results: Thirty patients (45.4%) had neuropathies remote from procedural sites and 36 patients (54.5%) had neuropathies in close proximity to procedural sites. Half of the remote neuropathies (15/30) developed following relatively short procedures. In 27% of cases (8/30) remote neuropathies were bilateral. Seven patients developed neuropathies remote from operative sites following hip arthroplasties (7/30: 23.3%), making hip arthroplasty the most common procedure associated with remote neuropathies.Sciatic neuropathies due to hip arthroplasty (12/36, 33.3%) accounted for the majority of neuropathies occurring in close proximity to operative sites.Five medial cutaneous nerve of forearm neuropathies occurred following arterio-venous fistula (AVF) formation. Conclusions: An array of surgical procedures may be complicated by neuropathy. Almost half of post-procedure neuropathies occur remote from the site of procedure, emphasizing the need to try to prevent not just local, but also remote neuropathies. Mechanical factors and patient positioning should be considered in the prevention of post-operative neuropathies. There is a possible association between AVF formation and medial cutaneous nerve of forearm neuropathy, which requires further study for validation.

Excitability changes in the sciatic nerve and triceps surae muscle after spinal cord injury in mice

Zaghloul Ahmed — 2010-04-18T00:00:00Z

Background: From the onset to the chronic phase of spinal cord injury (SCI), peripheral axons and muscles are subjected to abnormal states of activity. This starts with very intense spasms during the first instant of SCI, through a no activity flaccidity phase, to a chronic hyperactivity phase. It remains unclear how the nature of this sequence may affect the peripheral axons and muscles. Methods: We set out to investigate the changes in excitability of the sciatic nerve and to characterize the properties of muscle contractility after contusive injury of the mouse thoracic spinal cord. Results: The following changes were observed in animals after SCI: 1) The sciatic nerve compound action potential was of higher amplitudes and lower threshold, with the longer strength-duration time constant and faster conduction velocity; 2) The latency of the onset of muscle contraction of the triceps surae muscle was significantly shorter in animals with SCI; 3) The muscle twitches expressed slower rising and falling slopes, which were accompanied by prolonged contraction duration in SCI animals compared to controls. Conclusion: These findings suggest that in peripheral nerves SCI promotes hyperexcitability, which might contribute to mechanisms of spastic syndrome.

Surgical fasciectomy of the trapezius muscle combined with neurolysis of the Spinal accessory nerve; results and long-term follow-up in 30 consecutive cases of refractory chronic whiplash syndrome

N Nystrom — 2010-04-07T00:00:00Z

Background: Chronic problems from whiplash trauma generally include headache, pain and neck stiffness that may prove refractory to conservative treatment modalities. As has previously been reported, such afflicted patients may experience significant temporary relief with injections of local anesthetic to painful trigger points in muscles of the shoulder and neck, or lasting symptomatic improvement through surgical excision of myofascial trigger points. In a subset of patients who present with chronic whiplash syndrome, the clinical findings suggest an affliction of the spinal accessory nerve (CN XI, SAN) by entrapment under the fascia of the trapezius muscle. The present study was undertaken to assess the effectiveness of SAN neurolysis in chronic whiplash syndrome. Methods: A standardized questionnaire and a linear visual-analogue scale graded 0-10 was used to assess disability related to five symptoms (pain, headache, insomnia, weakness, and stiffness) before, and one year after surgery in a series of thirty consecutive patients. Results: The preoperative duration of symptoms ranged from seven months to 13 years. The following changes in disability scores were documented one year after surgery: Overall pain decreased from 9.5 +/- 0.9 to 3.2 +/- 2.6 (p < 0.001); headaches from 8.2 +/- 2.9 to 2.3 +/- 2.8 (p < 0.001); insomnia from 7.5 +/- 2.4 to 3.8 +/- 2.8 (p < 0.001); weakness from 7.6 +/- 2.6 to 3.6 +/- 2.8 (p < 0.001); and stiffness from 7.0 +/- 3.2 to 2.6 +/- 2.7 (p < 0.001). Conclusions: Entrapment of the spinal accessory nerve and/or chronic compartment syndrome of the trapezius muscle may cause chronic debilitating pain after whiplash trauma, without radiological or electrodiagnostic evidence of injury. In such cases, surgical treatment may provide lasting relief.

Novel model for end-neuroma formation in the amputated rabbit forelimb

Peter Kim — 2010-03-18T00:00:00Z

Background: The forelimb amputee poses many reconstructive challenges in the clinical setting, and there is a paucity of established surgical models for study. To further elucidate the pathogenic process in amputation neuroma formation, we created a reproducible, well-tolerated rabbit forelimb amputation model. Methods: Upon approval from the Institutional Animal Care and Use Committee, 5 New Zealand White rabbits underwent left forelimb amputation. During this initial surgery, the median, radial and ulnar nerves were transected 1.6-2.5 (mean 2.0) cm distal to the brachial plexus, transposed onto the anterior chest wall and preserved at length. Six weeks subsequent to the amputation, the distal 5 mm of each neuroma was excised, and the remaining stump underwent histomorphometric analysis. Results: The nerve cross sectional areas increased by factors of 1.99, 3.17, and 2.59 in the median (p = 0.077), radial (p < 0.0001) and the ulnar (p = 0.0026) nerves, respectively. At the axonal level, the number and cross-sectional area of myelinated fibers demonstrated an inverse relationship whereby the number of myelinated fibers in the median, radial and ulnar nerves increased by factors of 5.13 (p = 0.0043), 5.25 (p = 0.0056) and 5.59 (p = 0.0027), and the cross-sectional areas of these myelinated fibers decreased by factors of 4.62 (p < 0.001), 3.51 (p < 0.01), and 4.29 (p = 0.0259), respectively. Conclusion: Given that the surgical model appears well-tolerated by the rabbits and that patterns of morphologic change are consistent and reproducible, we are encouraged to further investigate the utility of this model in the pathogenesis of neuroma formation.

International symposium on peripheral nerve repair and regeneration and 2nd club Brunelli meeting

Mehmet Turgut — 2010-03-09T00:00:00Z

The International Symposium "Peripheral Nerve Repair and Regeneration and 2nd Club Brunelli Meeting" was held on December 4-5, 2009 in Turin, Italy (Organizers: Bruno Battiston, Stefano Geuna, Isabelle Perroteau, Pierluigi Tos). Interest in the study of peripheral nerve regeneration is very much alive because complete recovery of nerve function almost never occurs after nerve reconstruction and, often, the clinical outcome is rather poor. Therefore, there is a need for defining innovative strategies for improving the success of recovery after nerve lesion and repair and this meeting was intended to discuss, from a multidisciplinary point of view, some of today's most important issues in this scientific field, arising from both basic and clinical neurosciences.