Berberine enhances survival and axonal regeneration of motoneurons following spinal root avulsion and re-implantation in rats.

Brachial plexus avulsion (BPA) occurs when the spinal nerve roots are pulled away from the surface of the spinal cord and disconnects neuronal cell body from its distal downstream axon, which induces massive motoneuron death, motor axon degeneration and de-innervation of targeted muscles, thereby resulting in permanent paralysis of motor functions in the upper limb. Avulsion injury triggers oxidative stress and intense local neuroinflammation at the lesioned site, leading to the death of most motoneurons. Berberine (BBR), a natural isoquinoline alkaloid derived from medicinal herbs of Berberis and Coptis species, has been reported to possess neuro-protective, anti-inflammatory and anti-oxidative effects in various animal models of central nervous system (CNS)-related disorders. In this study, we aimed to investigate the effect of BBR on motoneuron survival and axonal regeneration following spinal root avulsion plus re-implantation in rats. Our results indicated BBR significantly accelerated motor function recovery in the forelimb as revealed by the increased Terzis grooming test score, facilitated motor axon regeneration as evidenced by the elevated number of Fluoro-Gold-labeled and P75-positive regenerative motoneurons. The survival of motoneurons was notably promoted by BBR administration presented with boosted ChAT-immunopositive and neutral red-stained neurons. BBR treatment efficiently alleviated muscle atrophy, attenuated functional motor endplates loss in biceps and prevented the reduction of motor axons in the musculocutaneous nerve. Additionally, BBR treatment markedly mitigated the avulsion-induced neuroinflammation via inhibiting microglial and astroglial reactivity, up-regulated the expression of antioxidative indicator Cu/Zn SOD, and down-regulated the levels of nNOS, 3-NT, lipid peroxidation and NF-κB, as well as promoted SIRT1, PI3K and Akt activation. Collectively, BBR might be a promising therapy to assist re-implantation surgery for the treatment of BPA.

Risk factors for peripheral nerve injuries following neuraxial labour analgesia: a nested case-control study.

BACKGROUND: Post-partum lower extremity motor and sensory dysfunctions occur in 0.1-9.2‰ of deliveries. While macrosomia, lithotomy position and forceps use are well-identified causes of peripheral nerve injuries, additional contributors such as patient condition and anaesthesia care may also have to be considered. METHODS: We performed a case-control study nested in a cohort of 19,840 patients having neuraxial anaesthesia for childbirth. Cases were all patients who developed motor or sensory dysfunction of lower extremities in the post-partum period. These were compared, using Chi-square, Fisher's exact test, logistic regression and time series, to a random sample of controls without any neurological symptoms or injury. RESULTS: We identified 19 (0.96‰) patients with peripheral nerve injuries of which 15 (0.76‰) were likely associated with obstetrical care. In four additional cases (0.20‰), a nerve root injury due to the Tuohy needle was suspected. Univariate risk factors were: a gestational age ≥ 41 weeks, Odds Ratio (OR) 3.8; 95% CI: 1.1-13.1, late initiation of neuraxial anaesthesia OR 8.2; 95% CI: 1.8-37.9, a repeated anaesthetic procedure OR 2.8; 95% CI: 1.0-7.8, assisted delivery with forceps OR 9.8; 95% CI: 1.2-114.1 and newborn birth weight > 3.5 kg with an OR 6.8; 95% CI: 2.0-22.5. CONCLUSION: Obstetrical related factors are the most prominent risk associated with peripheral nerve injuries. This study highlights however that patient and anaesthesia-related factors may also contribute to peripheral nerve injuries.

Lithium accelerates functional motor recovery by improving remyelination of regenerating axons following ventral root avulsion and reimplantation.

Brachial plexus injury (BPI) often involves the complete or partial avulsion of one or more of the cervical nerve roots, which leads to permanent paralysis of the innervated muscles. Reimplantation surgery has been attempted as a clinical treatment for brachial plexus root avulsion but has failed to achieve complete functional recovery. Lithium is a mood stabilizer drug that is used to treat bipolar disorder; however, its effects on spinal cord or peripheral nerve injuries have also been reported. The purpose of this study was to investigate whether lithium can improve functional motor recovery after ventral root avulsion and reimplantation in a rat model of BPI. The results showed that systemic treatment with a clinical dose of lithium promoted motor neuron outgrowth and increased the efficiency of motor unit regeneration through enhanced remyelination. An analysis of myelin-associated genes showed that the effects of lithium started during the early phase of remyelination and persisted through the late stage of the process. Efficient remyelination of the regenerated axons in the lithium-treated rats led to an earlier functional recovery. Therefore, we demonstrated that lithium might be a potential clinical treatment for BPI in combination with reimplantation surgery.

[Effects of Yiqi Huayu Decoction on brain-derived neurotrophic factor expression in rats with lumbar nerve root injury].

OBJECTIVE: To observe the effects of Yiqi Huayu Decoction, a compound traditional Chinese herbal medicine, on brain-derived neurotrophic factor (BDNF) expression in lumbar nerve root and soleus of rats after lumbar nerve root compression injury. METHODS: A total of 120 male SD rats were randomly allocated into sham-operated group, untreated group, methycobal injection group and Yiqi Huayu Decoction group. Surgery were performed on rats of untreated group, methycobal injection group and Yiqi Huayu Decoction group by placing a micro-silica gel on right L(4) dorsal root ganglia, while rats in sham-operated group received skin and paravertebral muscle incision only. Rats in the methycobal injection group and the Yiqi Huayu Decoction group were given intramuscular injection of methycobal and intragastric administration of Yiqi Huayu Decoction respectively. Rats in the sham-operated group and the untreated group received intragastric administration of normal saline of equal volume as Yiqi Huayu Decoction. The compressed nerve roots and right soleus were harvested after 10-, 30- and 60-day treatment. Microstructure of the compressed nerve roots were revealed under a transmission electron microscope. BDNF protein expression in the compressed nerve roots and mRNA expression in right solues were detected with enzyme-linked immunosorbent assay (ELISA) and real-time quantitative reverse transcription-polymerase chain reaction respectively. RESULTS: The protein expression level of BDNF in compressed nerve root in the untreated group was slightly changed with no significance as compared with sham-operated group. BDNF protein expression in the Yiqi Huayu Decoction group was gradually increased and reached the peak level after 60-day treatment with significant difference as compared with the untreated group (P<.01). The expression of BDNF mRNA in soleus was significantly up-regulated 10 days after nerve root injury (P<0.01), and was slowly decreased to the normal level at day 60 (P>0.05). Compared with the untreated group, BDNF mRNA expression in soleus muscle in the Yiqi Huayu Decoction group was significantly down-regulated after 10-day treatment (P<0.01), while was increased after 60-day treatment (P<0.01). CONCLUSION: Yiqi Huayu Decoction can inhibit the increase of BDNF expression at the early phase after nerve injury, which may have something to do with alleviation of neuropathic pain, and increase BDNF expression at the late phase to promote nerve regeneration.

Sacral nerve stimulation as an option for the treatment of faecal incontinence in patients suffering from cauda equina syndrome.

STUDY DESIGN: Retrospective clinical study with 1-year follow-up. OBJECTIVES: Treatment of faecal incontinence by permanent sacral nerve stimulation (SNS) in patients suffering from cauda equina syndrome (CES). SETTING: Klosterneuburg, Austria. BACKGROUND AND PURPOSE: A flaccid paresis of the sphincter ani muscle and the pelvic floor combined with faecal incontinence can occur in patients suffering from CES as a result of a trauma in the region of the lumbar spine. If the incontinence cannot be managed by the use of laxatives or anal tampons, the patient is restricted in his/her quality of life. Thus, it was our aim to improve sphincter function and anal sensitivity to achieve voluntary rectal defaecation. MATERIALS AND METHODS: The functional integrity of at least one sacral root (S2-S4) was determined through percutaneous nerve evaluation (PNE). Following this analysis, a period of external temporary SNS was performed to evaluate the functional effect. If there was a decrease in the number of episodes of faecal incontinence during this evaluation period, a neurostimulation device (InterStim; Medtronic) was implanted. PATIENTS: A total of 11 patients suffering from flaccid paresis of the anal sphincter muscle and faecal incontinence caused by CES underwent PNE, which was successful in 8 patients. Two of these patients were eliminated from the procedure at the end of the temporary SNS period, one patient refused the permanent implantation. Therefore, five patients proceeded to permanent implantation, which led to an improved continence in all the cases. DISCUSSION: In the synopsis of the preoperative proctologic and neurological findings, successful electric stimulation of the sacral roots can be expected in incomplete CES. In the case of flaccid paresis of the anal sphincter muscles caused by an incomplete CES, permanent SNS offers a promising option for the treatment of faecal incontinence. .

Vein grafts used as nerve conduits for obstetrical brachial plexus palsy reconstruction.

BACKGROUND: Limited availability of donor nerve grafts along with donor-site morbidity has stimulated research toward other alternatives for the repair of severe nerve injuries. The authors provide a comprehensive review of "tubulization" biology and share with the readers their experience with two cases of obstetrical brachial plexus paralysis where they used vein grafts with "minced" nerve tissue, to accomplish connectivity of proximal donors with distal targets. Usage of vascular tissue as conduits for nerve regeneration was first reported more than 100 years ago. It has been suggested that the vein's wall allows diffusion of the proper nutrients for nerve regeneration, acts as a barrier against ingrowth of scar, and prevents wastage of regenerating axons. METHODS: In this report, vein grafts of 2.4, 3.5, and 22 cm in length filled with minced peripheral nerve tissue were used as bridges in two cases of obstetrical brachial plexus paralysis. RESULTS: By filling the vein lumen with small pieces of nerve tissue suspended in a heparinized saline solution, a potential problem associated with vein collapse caused by compression was solved. CONCLUSION: The authors suggest that tubulization techniques should be kept in mind in clinical practice when autologous nerve grafts are insufficient for distal target connectivity or as an alternative to conventional nerve grafts for bridging certain nerve defects.

Ventral and dorsal root injury after oxygen-ozone therapy for lumbar disk herniation.

BACKGROUND: O2O3 therapy has become a largely diffused treatment for lumbar disk herniation; this procedure is considered generally risk-free. CASE DESCRIPTION: We report a case of ventral and dorsal root injury occurring after transcutaneous intradiscal infiltration of O2O3 for L4-L5 disk herniation. CONCLUSIONS: Until randomized controlled trials on efficacy and short-term safety have been carried out, we think that physicians should be informed about the risk of potential complications when recommending this procedure.

Characterization of three different sensory fibers by use of neonatal capsaicin treatment, spinal antagonism and a novel electrical stimulation-induced paw flexion test.

In the present study, we first report an in vivo characterization of flexor responses induced by three distinct sine-wave stimuli in the electrical stimulation-induced paw flexion (EPF) test in mice. The fixed sine-wave electric stimulations of 5 Hz (C-fiber), 250 Hz (Adelta-fiber) and 2000 Hz (Abeta-fiber) to the hind paw of mice induced a paw-flexion response and vocalization. The average threshold for paw flexor responses by sine-wave stimulations was much lower than that for vocalization. Neonatally (P3) pretreatment with capsaicin to degenerate polymodal substance P-ergic C-fiber neurons increased the threshold to 5 Hz (C-fiber) stimuli, but not to 250 Hz (Adelta-fiber) and 2000 Hz (Abeta-fiber). The flexor responses to 5 Hz stimuli were significantly blocked by intrathecal (i.t.) pretreatment with both CP-99994 and MK-801, an NK1 and NMDA receptor antagonist, respectively, but not by CNQX, an AMPA/kainate receptor antagonist. On the other hand, the flexor responses induced by 250 Hz stimuli were blocked by MK-801 (i.t.) but not by CP-99994 or CNQX. In contrast, flexor responses induced by 2000 Hz stimuli were only blocked by CNQX treatment. These data suggest that we have identified three pharmacologically different categories of responses mediated through different primary afferent fibers. Furthermore, we also carried out characterization of the in vivo functional sensitivity of each of the sensory fiber types in nerve-injured mice using the EPF test, and found that the threshold to both 250 Hz and 2000 Hz stimulations were markedly decreased, whereas the threshold to 5 Hz stimulations was significantly increased. Thus we found opposing effects on specific sensory fiber-mediated responses as a result of nerve injury in mice. These results also suggest that the EPF analysis is useful for the evaluation of plasticity in sensory functions in animal disease models.

Motorneuron protection by N-acetyl-cysteine after ventral root avulsion and ventral rhizotomy.

Motor recovery after proximal nerve injury remains extremely poor, despite advances in surgical care. Several neurobiological hurdles are implicated, the most fundamental being extensive cell death within the motorneuron pool. N-acetyl-cysteine almost completely protects sensory neurons after peripheral axotomy, hence its efficacy in protecting motorneurons after ventral root avulsion/rhizotomy was investigated. In adult rats, the motorneurons supplying medial gastrocnemius were unilaterally pre-labelled with retrograde tracer (true-blue/fluoro-gold), prior to L5 and 6 ventral root avulsion, or rhizotomy. Groups received either intraperitoneal N-acetyl-cysteine (ip, 150 or 750 mg/kg/day), immediate or delayed intrathecal N-acetyl-cysteine treatment (it, 2.4 mg/day), or saline; untreated animals served as controls. Either 4 (avulsion model) or 8 (rhizotomy model) weeks later, the pre-labelled motorneurons' mean soma area and survival were quantified. Untreated controls possessed markedly fewer motorneurons than normal due to cell death (avulsion 53% death; rhizotomy 26% death, P<0.01 vs. normal). Motorneurons were significantly protected by N-acetyl-cysteine after avulsion (ip 150 mg/kg/day 40% death; it 30% death, P<0.01 vs. no treatment), but particularly after rhizotomy (ip 150 mg/kg/day 17% death; ip 750 mg/kg/day 7% death; it 5% death, P<0.05 vs. no treatment). Delaying intrathecal treatment for 1 week after avulsion did not impair neuroprotection, but a 2-week delay was deleterious (42% death, P<0.05 vs. 1-week delay, 32% death). Treatment prevented the decrease in soma area usually found after both types of injury. N-acetyl-cysteine has considerable clinical potential for adjuvant treatment of major proximal nerve injuries, including brachial plexus injury, in order that motorneurons may survive until surgical repair facilitates regeneration.

Las lecciones derivadas del ASA Closed Claims Project (ASACCP). Proyecto de la ASA acerca de las razones que promovieron demandas contra anestesiólogos cuyos casos estuviesen ya archivados: 4a. parte. Anestesia Regional. Análisis de las demandas sobre casos/hechos asociados con la anestesia regional en la sala de operaciones / Lessons learned fron the ASA Closed Claims Project (ASACCP). Project about the reasons for which claims against anesthesiologists were renewed in cases that had already been closed: part. 4. Regional Anesthesia. Analysis of claims concerning regional anesthesia in the OR

Cuando se comparan las consecuencias de los accidentes anestésicos reclamados que constan en la base de datos del ASA CCP (Closed Claims Project), es significativo señalar que hubo un alto porcentaje de lesiones temporarias o no incapacitantes en los casos de anestesia regional (64 por ciento vs 46 por ciento p<0,05). Entre las lesiones incapacitantes permanentes derivadas de injurias del sistema nervioso periférico se hallan manifestaciones como la paraplejía y la cuadriplejía. Catorce de las reclamaciones legales asociadas con la paraplejía se debieron a síndromes de la anestesia espinal anterior. Los daños neurológicos permanentes fueron la causa más común de los daños incapacitantes, el más frecuente de los cuales (23 por ciento) fue asociado a bloqueos nerviosos para anestesia ocular (13 retrobulbares, 3 peribulbares) en los que hubo pérdida de la visión del ojo afectado. De todas maneras, se debe señalar que las complicaciones neurológicas como manifestaciones secundarias a la utilización de anestésicos locales para anestesia regional son muy poco frecuentes (0,02 y 0,07 por ciento de los casos), aunque es bastante común observar la aparición de manifestaciones neurológicas transitorias (entre 0,01 y 0,8 por ciento). La parestesia y el dolor durante la inyección son señales peligrosas ya que anuncian la posibilidad de la complicación. Se han descripto también abscesos peridurales y meningitis, en especial cuando se realizan bloqueos centrales con catéteres de pequeño diámetro a fin de alcanzar analgesia central para el dolor crónico. En la base de datos de la Mutual de Médicos Anestesiólogos de Buenos Aires están registradas las demandas realizadas contra anestesiólogos y los casos en los cuales los médicos, enfrentados a un incidente crítico, notifican la situación en previsión de una eventual demanda. Al igual que en el estudio de la ASACCP, desconocemos el número total de anestesia realizadas por los colegas adheridos. Hasta el 2004 hubo 339 notificaciones que incluyen 74 demandas, 24 causas penales y 50 causas civiles; 124 casos correspondieron a la anestesia regional, mientras que 215 formaron el grupo de pacientes que recibieron anestesia general. En 8 de los pacientes que presentaron radiculopatías se realizó una anestesia subaracnoidea con bupivacaína al 0,5 por ciento en solución hiperbara, habiéndose inyectado 15 mg (3 ml) de la solución anestésica...(AU)

Las lecciones derivadas del ASA Closed Claims Project (ASACCP). Proyecto de la ASA acerca de las razones que promovieron demandas contra anestesiólogos cuyos casos estuviesen ya archivados: 4a. parte. Anestesia Regional. Análisis de las demandas sobre casos/hechos asociados con la anestesia regional en la sala de operaciones / Lessons learned fron the ASA Closed Claims Project (ASACCP). Project about the reasons for which claims against anesthesiologists were renewed in cases that had already been closed: part. 4. Regional Anesthesia. Analysis of claims concerning regional anesthesia in the OR

Cuando se comparan las consecuencias de los accidentes anestésicos reclamados que constan en la base de datos del ASA CCP (Closed Claims Project), es significativo señalar que hubo un alto porcentaje de lesiones temporarias o no incapacitantes en los casos de anestesia regional (64 por ciento vs 46 por ciento p<0,05). Entre las lesiones incapacitantes permanentes derivadas de injurias del sistema nervioso periférico se hallan manifestaciones como la paraplejía y la cuadriplejía. Catorce de las reclamaciones legales asociadas con la paraplejía se debieron a síndromes de la anestesia espinal anterior. Los daños neurológicos permanentes fueron la causa más común de los daños incapacitantes, el más frecuente de los cuales (23 por ciento) fue asociado a bloqueos nerviosos para anestesia ocular (13 retrobulbares, 3 peribulbares) en los que hubo pérdida de la visión del ojo afectado. De todas maneras, se debe señalar que las complicaciones neurológicas como manifestaciones secundarias a la utilización de anestésicos locales para anestesia regional son muy poco frecuentes (0,02 y 0,07 por ciento de los casos), aunque es bastante común observar la aparición de manifestaciones neurológicas transitorias (entre 0,01 y 0,8 por ciento). La parestesia y el dolor durante la inyección son señales peligrosas ya que anuncian la posibilidad de la complicación. Se han descripto también abscesos peridurales y meningitis, en especial cuando se realizan bloqueos centrales con catéteres de pequeño diámetro a fin de alcanzar analgesia central para el dolor crónico. En la base de datos de la Mutual de Médicos Anestesiólogos de Buenos Aires están registradas las demandas realizadas contra anestesiólogos y los casos en los cuales los médicos, enfrentados a un incidente crítico, notifican la situación en previsión de una eventual demanda. Al igual que en el estudio de la ASACCP, desconocemos el número total de anestesia realizadas por los colegas adheridos. Hasta el 2004 hubo 339 notificaciones que incluyen 74 demandas, 24 causas penales y 50 causas civiles; 124 casos correspondieron a la anestesia regional, mientras que 215 formaron el grupo de pacientes que recibieron anestesia general. En 8 de los pacientes que presentaron radiculopatías se realizó una anestesia subaracnoidea con bupivacaína al 0,5 por ciento en solución hiperbara, habiéndose inyectado 15 mg (3 ml) de la solución anestésica...

Gastrointestinal symptoms secondary to implanted spinal cord stimulators.

IMPLICATIONS: We report severe gastrointestinal symptoms in two patients who had implanted spinal cord stimulators. These side effects were severe enough to require cessation of the stimulation, even though the patients reported significantly improved analgesia. It is important for clinicians caring for patients with these devices to be aware of these potentially severe side effects.

Spinal cord stimulation for nonspecific limb pain versus neuropathic pain and spontaneous versus evoked pain.

OBJECTIVE: To compare the outcome of spinal cord stimulation (SCS) in patients with nonspecific limb pain versus patients with neuropathic pain syndromes and in patients with spontaneous versus evoked pain. METHODS: A retrospective review of 122 patients accepted for treatment with SCS between January 1990 and December 1998 was conducted. All patients first underwent a trial of SCS with a monopolar epidural electrode. Seventy-four patients had a successful trial and underwent permanent implantation of the monopolar electrode used for the trial (19 patients), or a quadripolar electrode (53 patients), or a Resume quadripolar electrode via laminotomy (2 patients). RESULTS: Of the 74 patients, 60.7% underwent implantation of a permanent device and were followed for an average of 3.9 years (range, 0.3-9 yr). Early failure (within 1 yr) occurred in 20.3% of patients, and late failure (after 1 yr) occurred in 33.8% of patients. Overall, 45.9% of patients were still receiving SCS at latest follow-up. Successful SCS (>50% reduction in pain for 1 yr) occurred in 83.3% of patients with nonspecific leg pain, 89.5% of patients with limb pain associated with root injury, and 73.9% of patients with nerve neuropathic pain. SCS was less effective for the control of allodynia or hyperpathia than for spontaneous pain associated with neuropathic pain syndromes. Third-party involvement did not influence outcome. There was a lesser incidence of surgical revisions when quadripolar leads were used than with monopolar electrodes. CONCLUSION: SCS is as effective for treating nonspecific limb pain as it is for treating neuropathic pain, including limb pain associated with root damage.

[Non-cerebrovascular complication in chirotherapy manipulation of the cervical vertebrae]. / Nicht-zerebrovaskuläre Komplikationen der chirotherapeutischen HWS-Manipulation.

PURPOSE: Chirotherapy is a popular and successful management option for reversible functional disorders of the cervical spine. Though rarely observed, complications do occur, mainly involving the cerebrovascular system. By means of the here described case and a literature survey, we aim to highlight non-cerebrovascular complications of chirotherapeutic cervical spine manipulation. RESULTS: A 43-year-old male initially consulted an ENT specialist, suffering from tinnitus aurium and loss of hearing ability. His hearing significantly increased after intravenous drug therapy, but the tinnitus remained. During chiropractic manipulation of the cervical spine by an orthopaedic surgeon for the tinnitus, the patient described severe neck pain following a clearly audible clicking sound. Scans of the cervical spine prior to and after manipulation showed an intracapsular/intraosseus oedema of the facet joints C2/C3 with lesion of the nerve root C3, most probably induced by chirotherapy. CONCLUSION: Although complications after chiropractic manipulation are extremely rare, treatment of the spine, especially the cervical spine, is not wholly harmless. An adequate history taking followed by clinical and radiographic patient evaluation is necessary to keep the risk of iatrogenic trauma at a minimum. Above all, the chiropractic manipulation of the cervical spine belongs in the hands of a qualified and experienced medical practitioner.

[Peripheral and central nervous system stimulation in chronic therapy-resistant pain. Background, hypothetical mechanisms and clinical experiences]. / Perifer och centralnervös stimulering vid kronisk terapiresistent smärta. Bakgrund, hypotetiska mekanismer och kliniska erfarenheter.

Severe neurogenic pain still constitutes a major problem since it is often resistant to conventional therapy. During the last 30 years electric activation of pain inhibitory mechanisms through stimulation both of peripheral nerves and of central nervous circuits has been used to great advantage. The simplest method of stimulation, transcutaneous electric nerve stimulation (TENS), is extensively used by physiotherapists as well as in pain clinics. The patient should always get his own stimulator for use at home. TENS originally served as a screening method to identify patients suitable for spinal cord stimulation therapy (SCS). The main indication is severe neuropathic pain of peripheral origin, but SCS has also been found valuable in extremity ischemia as well as in refractory angina pectoris. The most severe cases of neuropathic pain may benefit from intracranial stimulation via electrodes placed stereotactically in the posteromedial thalamus or epidurally over the motor cortex.

Effects of dorsal root transection on morphology and chemical composition of degenerating nerve fibers and reactive astrocytes in the dorsal funiculus.

The morphology and chemical (elemental) composition of the dorsal funiculus of the rat spinal cord were examined 1 and 7 days after unilateral transection (rhizotomy) of the L4 and L5 dorsal roots, using light and electron microscopy as well as X-ray microanalysis. Changes were observed only in the dorsal funiculus on the side of injury and included disintegration of the axonal cytoskeleton, enlargement of axonal mitochondria, and widening of the myelin lamellae of the injured axons. X-ray microanalysis demonstrated a significant increase in intraaxonal sodium at 1 day after injury. This increase was abolished at 7 days, but at this stage there was a significant lowering of potassium in axons and myelin sheaths and of phosphorus in myelin as well as a marked increase in calcium in the axoplasm of the degenerating axons. The nonneuronal cell compartment, largely composed of astrocytes, showed elevated sodium, chlorine, and calcium and lowered potassium levels. The changes in chemical composition paralleled an increase in immunoreactivity for the calcium-binding Mts1 (S100A4) protein, which is exclusively expressed by white matter astrocytes. The influx of calcium is likely to play a crucial role in the loss of axonal integrity after rhizotomy, while the alterations in potassium, and perhaps also phosphorus, may contribute to activation of the nonneuronal cells, including the up-regulation of Mts1 expression in astrocytes.

Neurosurgical management of neuropathic pain.

Neuropathic pain is a very difficult problem with which the neurosurgeon frequently must deal. The neurosurgical methods to be considered are: (1) modulative, by using neurostimulation or implanted drug delivery systems, and (2) ablative, by making selective therapeutic lesions in well-defined and identified targets proven to sustain pain mechanisms (especially DREZotomy).

[The effect of electroacupuncture stimulation an neurotrophic substance in cat spinal dorsal horn].

For exploration of the mechanism of collateral sprouting from injured spinal cord, polyacrylamide gel electrophoresis (PAGE) and modified hanging drop culture method were used to examine the effect of acupuncture on the amount and the biological activity of neurotrophic substance in larger than 50 kd fraction of dorsal horn in cat subjected to partial dorsal rhizotomy. The results showed that the amount of protein in relative mobility (RM) 0.1 zone increased significantly in the acupuncture-operated group by PAGE and that of protein in RM 0.5 zone decreased significantly as compared with the unoperated group. While this data was compared with the data of another operated group in our lab, the amount of RM 0.1 protein of the acupuncture-operated group was significantly higher than that of the latter group; however, no obvious difference was noted between the two groups in the amount of RM 0.5 protein. It suggests that acupuncture may promote tha amount of RM 0.1 protein to increase, but acupuncture has no influence on the amount of RM 0.5 protein. Also, the results showed that, in culture, accompanying with the increase in amount, the activity of RM 0.1 protein for promoting DRG neurite-outgrowth increased. This indicates that the RM 0.1 protein has a function to promote DRG neurite-outgrowth, but the RM 0.5 protein has no obvious effect on DRG neurite-outgrowth.

Electrical stimulation of the trigeminal nerve root for the treatment of chronic facial pain.

Between March 1990 and December 1992, 23 patients with chronic intractable facial pain due to various forms of injury to the trigeminal nerve or nerve root underwent implantation of an electrical stimulating system to treat their pain. All patients had failed previous extensive pain treatment efforts. A monopolar platinum-iridium electrode was implanted on the trigeminal nerve root via percutaneous puncture of the foramen ovale. All patients experienced at least 50% reduction in pain intensity during a period of trial stimulation and underwent internalization of the electrode and connection to a completely implanted pulse generator. Independent assessment of the effect of stimulation was obtained by a specially trained nurse practitioner. Over a mean follow-up period of 24 months, six patients reported nearly complete relief of pain and six others reported at least a 50% reduction in pain intensity using a visual analog scale. Thus, 12 (52%) of the 23 patients achieved 50% or greater reduction in pain intensity. Although changes in the patterns of analgesic medication usage were few, six patients (26%) now experience a normal life style. Only one complication was seen, namely a dislocated electrode, which was easily replaced. Chronic electrical stimulation of the trigeminal nerve root appears to be an easy and safe technique for providing relief of chronic facial pain related to injury to the trigeminal nerve in a significant number of patients.