Increased Serotonergic Innervation of Lumbosacral Motoneurons of Rolling Mouse Nagoya in Correlation with Abnormal Hindlimb Extension

Rolling Mouse Nagoya (RMN) carries a mutation in a gene encoding for alpha(1A) subunit of P/Q-type Ca(2+) channel (Ca(v)2.1). In addition to ataxia, this mutant mouse exhibits abnormal hindlimb extension, which is characterized by a sustained excessive tone of hindlimb extensor muscles. This study aimed to clarify whether serotonergic (5-HTergic) innervation of the spinal motoneurons was altered in RMN in relation to the abnormal hindlimb extension. The density of 5-HT immunoreactive fibres in the ventral horn of lumbar and sacral regions of spinal cord was significantly greater in RMN than in controls. Retrograde wheat germ agglutinin-conjugated horseradish peroxidase (WGA-HRP) labelling combined with 5-HT immunostaining revealed that the number of 5-HT immunoreactive terminals adjoining femoris quadriceps motoneurons was about 2.5-fold greater in RMN than in controls. Furthermore, 5-HT immunostaining in the lumbar cord ventral horn was examined in three other Ca(v)2.1 mutant mice (tottering, leaner and pogo) as to whether or not they showed the abnormal hindlimb extension. Among these mutants, the increased density of 5-HT immunoreactive fibres was observed in correlation with the presence of the abnormal hindlimb extension. The results suggest an increased 5-HTergic innervation of the lumbosacral motoneurons in correlation with the abnormal hindlimb extension in RMN and other Ca(v)2.1 mutant mice. As 5-HT is known to induce the sustained membrane depolarizations without continuous excitatory synaptic inputs (plateau potentials) in spinal motoneurons, the increased 5-HTergic innervation may cause the sustained excitation of hindlimb extensor motoneurons, resulting in the abnormal hindlimb extension.

Contralateral neurologic deficits following microendoscopic lumbar surgery. Can it happen?

A contralateral neurologic deficit following microendoscopic discectomy (MED) or laminectomy (MEL) had not previously been reported. Between September 1999 and April 2004, 60 patients with symptomatic lumbar disc herniations or spinal stenotic syndrome received MED or MEL at the authors' institution. Three out of 60 patients were found to exhibit a contralateral neurologic deficit following unilateral microendoscopic surgery. All three patients complained of a newly developed, contralateral neurologic deficit following their operations. One MED patient with a concomitant contralateral disc herniation developed contralateral motor and sensory deficits and required immediate open surgery. At the two-year follow-up, a residual motor deficit was noted. The other two patients (1 MED, 1MEL) with temporary sensory deficits were only treated conservatively and experienced complete recovery one week and six weeks following the operation, respectively. Surgeons should pay close attention to the possibility that contralateral neurologic deficits may occur following MED or MEL. Our reports indicate that caution should be exercised when performing microendoscopic procedures on patients with substantial dural compromise, a concomitant contralateral disc herniation, or a lateral spinal stenosis, which may be etiologies.

Evaluation of the anatomic effect of physical therapy exercises for mobilization of lumbar spinal nerves and the dura mater in dogs

OBJECTIVE

To adapt and standardize neural tissue mobilization exercises, quantify nerve root movement, and assess the anatomic effects of lumbar spinal nerve and dural mobilization in dogs.

ANIMALS

15 canine cadavers.

PROCEDURES

5 cadavers were used in the preliminary part of the study to adapt 3 neural tissue mobilization physical therapy exercises to canine anatomy. In the other 10 cadavers, the L4 to L7 nerve roots and the dura at the level of T13 and L1 were isolated and marked. Movements during the physical therapy exercises were standardized by means of goniometric control. Movement of the nerve roots in response to each exercise was digitally measured. The effects of body weight and crownrump length on the distance of nerve root movement achieved during each exercise were also assessed. Each exercise was divided into 4 steps, and the overall distance of neural movement achieved was compared with distances achieved between steps.

RESULTS

Neural tissue mobilization exercises elicited visible and measurable movement of nerve roots L4 to L7 and of the dura at T13 and L1 in all cadavers.

CONCLUSIONS AND CLINICAL RELEVANCE

The physical therapy exercises evaluated had measurable effects on nerve roots L4 to L7 and the dura mater in the T13 and L1 segments. These exercises should be evaluated in clinical trials to validate their efficacy as primary treatments or ancillary postsurgical therapy in dogs with disorders of the thoracolumbar and lumbosacral segments of the vertebral column.

Lumbosacral Magnetic Root Stimulation in Lumbar Plexopathy

We report a 76-yr-old man with left femoral nerve distribution weakness resulting from a nontraumatic retroperitoneal hematoma associated with coumadin anticoagulation. Although electric root stimulation was relatively contraindicated, magnetic lumbosacral root stimulation identified a proximal conduction block allowing more extensive assessment of the nerve damage. To our knowledge, this is the first report of magnetic root stimulation in assessment of lumbosacral plexus dysfunction in retroperitoneal hematoma.

Expression patterns of Hox10 paralogous genes during lumbar spinal cord development

We have examined the expression of three paralogous Hox genes from E11.5 through E15.5 in the mouse spinal cord. These ages coincide with major phases of spinal cord neurogenesis, neuronal differentiation, cell migration, gliogenesis, and motor neuron cell death. The three genes, Hoxa10, Hoxc10, and Hoxd10, are all expressed in the lumbar spinal cord and have distinct expression patterns. Mutations in these three genes are known to affect motor neuron patterning. All three genes show lower levels of expression at the rostral limits of their domains, with selective regions of higher expression more caudally. Hoxa10 and Hoxd10 expression appears confined to postmitotic cell populations in the intermediate and ventral gray, while Hoxc10 is also expressed in proliferating cells in the dorsal ventricular zone. Hoxc10 and Hoxd10 expression is clearly excluded from the lateral motor columns at rostral lumbar levels but is present in this region more caudally. Double labeling demonstrates that Hoxc10 expression is correlated with ventrolateral LIM gene expression in the caudal part of the lumbar spinal cord.

Vanilloid receptor type 1-immunoreactive nerves in the rat urinary bladder and primary afferent neurones: The effects of age

The vanilloid receptor (VR1) is a molecular integrator of various painful stimuli, including capsaicin, acid and high temperature. VR1 protein functions both as a receptor for capsaicin and a transducer of noxious thermal stimuli. In addition, VR1 is well characterised at the terminals of sensory nerves involved in the pain pathway. VR1 is also expressed in a capsaicin-sensitive and peptide-containing sub-population of primary sensory nerves. Indirect immunohistochemistry was used to examine the distribution of nerves immunoreactive (ir) for VR1 in the base of the urinary bladder and in the neurones of the lumbosacral dorsal root ganglia (L1-L2 and L6-S1) of young adult (3 months) and aged (24 months) male rats. Semi-quantitative estimations of nerve densities were assessed and quantitative studies were also used to examine the effects of age on the percentage of VR1-ir dorsal root ganglion neurones. The bladder base in young adults showed dense VR1-ir fibres within the urothelium and in the subepithelium and fibres ranging from sparse to moderate in number in the muscle coat. In comparison to the young animals, the aged rats showed sparse to moderate densities of VR1-ir nerves in the subepithelium and sparse fibres in the muscle layers. In the lumbosacral dorsal root ganglia the percentage of VR1-ir neuronal profiles showed a significant reduction from (mean +/- SEM) 17.8 +/- 2% in the young adult to 12 +/- 1.6 in the aged rats. The present findings suggest that the effects of VR1 on bladder function (nociception and reflex micturition) are influenced by age and the reduction with age of VR1-ir neurones in the dorsal root ganglia could also have important implications for the micturition reflex.

The logical choice of muscles for the needle-EMG evaluation of lumbosacral radiculopathy

The objective of this study was to find the theoretically smallest subsets of muscles for needle-EMG (nEMG) screening of lumbosacral radiculopathies that ascertain that each root and its adjacent roots are represented by at least two muscles each, innervated by those roots via different peripheral nerves. A 23 and a 30 muscles muscle-sets and their myotomal innervation where derived from the literature, and rearranged into 15 and 19 unique muscle-groups by root and peripheral nerve innervation. All 2(15) and 2(19) subset combinations thereof were respectively identified. The criteria above were computed for each subset and the smallest subsets that qualified were retained. The number of muscles sampled per damaged root and the number of muscles sampled per adjacent roots in compliance with the objective above were computed. The smallest subsets satisfying the objective above were of 6, 7 and 9 muscles each, and are enumerated in . From these tables, each electromyographer may choose a set that best suits him, confident of its diagnostic parameters, while inflicting the least pain onto his patients, utilizing the shortest possible procedure, concluding a screen of all the roots at once, a screen that best differentiate between normal and damaged roots, and in most cases adequate for reaching the final diagnosis. Moreover, when needed, each set may be the basis for a more extensive workup.

Specializations in the lumbosacral vertebral canal and spinal cord of birds: evidence of a function as a sense organ which is involved in the control of walking

Birds are bipedal animals with a center of gravity rostral to the insertion of the hindlimbs. This imposes special demands on keeping balance when moving on the ground. Recently, specializations in the lumbosacral region have been suggested to function as a sense organ of equilibrium which is involved in the control of walking. Morphological, electrophysiological, behavioral and embryological evidence for such a function is reviewed. Birds have two nearly independent kinds of locomotion and it is suggested that two different sense organs play an important role in their respective control: the vestibular organ during flight and the lumbosacral system during walking.

Differential sympathetic outflow and vasoconstriction responses at kidney and skeletal muscles during fictive locomotion

We compared sympathetic and circulatory responses between kidney and skeletal muscles during fictive locomotion evoked by electrical stimulation of the mesencephalic locomotor region (MLR) in decerebrate and paralyzed rats ( n = 8). Stimulation of the MLR for 30 s at 40-μA current intensity significantly increased arterial pressure (+38 ± 6 mmHg), triceps surae muscle blood flow (+17 ± 3%), and both renal and lumbar sympathetic nerve activities (RSNA +113 ± 16%, LSNA +31 ± 7%). The stimulation also significantly decreased renal cortical blood flow (−18 ± 6%) and both renal cortical and triceps surae muscle vascular conductances (RCVC −38 ± 5%, TSMVC −17 ± 3%). The sympathetic and vascular conductance changes were significantly dependent on current intensity for stimulation at 20, 30, and 40 μA. The changes in LSNA and TSMVC were significantly less than those in RSNA and RCVC, respectively, at all current intensities. At the early stage of stimulation (0–10 s), decreases in RCVC and TSMVC were significantly correlated with increases in RSNA and LSNA, respectively. These data demonstrate that fictive locomotion induces less vasoconstriction in skeletal muscles than in kidney because of less sympathetic activation. This suggests that a neural mechanism mediated by central command contributes to blood flow distribution by evoking differential sympathetic outflow during exercise.

Verification of nerve root decompression during minimally-invasive lumbar microdiskectomy: a practical application of surgeon-driven evoked EMG

Lumbar microendoscopic diskectomy (MED) has gained widespread acceptance as an alternative to conventional open microdiskectomy due to several potential advantages, including reductions in postoperative pain and recovery time. However, constraints in visualization and working space present technical difficulties in the verification of nerve root decompression and the identification of sequestered disc fragments. This study was undertaken to investigate whether a surgeon-driven, evoked EMG paradigm could be used for intraoperative verification of nerve root decompression within the technical and mechanical confines of lumbar MED. Twenty-two patients underwent intraoperative EMG stimulation threshold recordings during lumbar microendoscopic diskectomy. In this series, the EMG threshold recorded directly from the nerve root immediately prior to diskectomy was 8.6 +/- 4.4 mA. Following decompression, the threshold was 4.2 +/- 2.1 mA. The difference in pre- and post-decompression EMG stimulation threshold, 4.4 +/- 4.0 mA, was statistically significant (p < 0.001). In two of the 22 cases (9.1 %), the EMG threshold was initially unchanged following diskectomy, and further exploration revealed sequestered disc fragments. After removal of these fragments, an appropriate decrease in the EMG threshold was observed. The results from this study suggest that surgeon-driven, evoked EMG threshold testing may provide a simple, effective adjunct to lumbar microendoscopic diskectomy for intraoperative verification of nerve root decompression.

[Application of minimally invasive lumbar sympathectomy in the treatment of patients with obliterating diseases of the lower extremity vessels]

The method of performance and immediate results of miniinvasive lumbar sympathectomy using retroperitoneal miniaccess were adduced in the work. In 2005 yr on the base of division of vascular surgery were operated 19 patients. Application of endoscopic instruments and optic system of illumination gave the possibility to remove lumbar sympathetic nodes in conditions of narrow (3-5 cm) surgical access and operative field. Introduction of miniinvasive method have promoted to reduce essentially the postoperative complications rate, the pain syndrome intensity, the reduction of duration of the patients postoperative rehabilitation, the cosmetic effect raising.

Anatomical description of the facet joint innervation and its implication in the treatment of recurrent back pain

AIM

Many techniques are used in the back pain treatment, standing out the facet denervation as a therapeutic option for pain that originates in the facet joints. It's known that the facet joint is an abundant area of nocireceptor innervation, although the distribution and the location of the involved branches have not being well demonstrated. A good comprehension about the affected innervation is very important to get an effective treatment. Purpose of study was to describe innervation of the lumbar facet joints, potentially used in the diagnosis and treatment of painful pictures of the lumbar region by facet syndrome.

STUDY DESIGN

anatomical study of nerve roots distribution of the facet joint 3 human corpses. The determination of the neurotomy s point was carried out by direct visualization and the radiological study in human parts.

METHODS

Three anatomical pieces of the human lumbar spine were dissected. In those 3 pieces, the facet joint innervation distribution was studied thoroughly using surgical microscope and microsurgical technique. In one of the pieces the needles positioning was first made to test through the radiological study the possible application of the precise denervation in low back pain treatment.

RESULTS

The L1 to L4 segments, each dorsal branch of root emits a medial branch that emerges from intertransversal ligament. This branch crosses the superior margin of the medial termination of transverse process, passing through the root of the superior articulate process. Each branch innerves the anterior region of the inferior facet and the inferior portion of articulation which one spins around. The L5 dorsal branch was larger than the superior branches. It emerges dorsally and in the inferior region on top of the sacrum wing. This nerve is in the bone fissure of the junction between the wing and the posterior region of the sacrum articular process. Near the inferior portion of the articular process, the nerve ramifies itself in lateral and medial branch. The medial branch comes back around the inferior portion of the lumbar-sacrum articulation that it innervates.

CONCLUSIONS

We didn't note great variations in the anatomy from L1 do L4. The L5 segment has a different distribution of the branches that should be considered when we do a percutaneous denervation procedure. The approach of the needle must touch the transverse process and feels the resistance of the articular joint . The determination of the neurotomy s point tends to become more precise denervation procedure.

Lateral femoral cutaneous nerve: an anatomic study

The purpose of our study was to determine the location of the lateral femoral cutaneous nerve and its branches at the inguinal ligament and proximal thigh. We think that further defining the location of the nerve and its branches based on certain measurements from known anatomic landmarks would enable us to determine a danger zone that could aid in preventing iatrogenic injury to the lateral femoral cutaneous nerve. The anatomic course of the lateral femoral cutaneous nerve was studied in 29 cadaver specimens and distances from various landmarks were recorded. In addition, the branching pattern of the nerves was recorded. We observed variability in the course and branching patterns of the lateral femoral cutaneous nerve. The lateral femoral cutaneous nerve was found to potentially be at risk as far as 7.3 cm medial to the anterior superior iliac spine along the inguinal ligament and as much as 11.3 cm distal on the sartorius muscle from the anterior superior iliac spine. As many as five branches of the lateral femoral cutaneous nerve were found and in 27.6% of cases the lateral femoral cutaneous nerve branched before traversing the inguinal ligament. We used this information to describe a danger zone, which could be used as a guide to help prevent unnecessary injury during certain procedures.

The sympatho-adrenal response and erythropoietin production in adaptation to hypoxia

The research activity upon erythropoiesis regulation carried out by the team in the Physiology Department and in the Institute of Medical Research of the Romanian Academy in Cluj-Napoca developed continuously after 1950. Our studies contributed to the isolation, identification and characterization of erythropoietin (Epo) and also to a better understanding of the nervous adaptation mechanisms to hypoxia. At present, it is well known that hypoxia acts upon erythropoiesis through Epo production. Direct central nervous stimulation through hypoxia induces, via a neuro-humoral mechanism, a sympatho-adrenal response and release of Epo. Adaptive polyglobulia as a response to hypoxia increases the capacity of oxygen binding and transport. In this paper we attempted to identify the role of the sympathetic nervous system in adaptation to hypoxia correlated with Epo secretion. Experiments were carried out in three groups of rats, respectively, with cervical, thoracic, and lumbar (without celiac) sympathectomy. The sympathectomized animals were submitted to hypobaric or to hemorrhagic hypoxia, in parallel with control groups. Erythrocytic parameters (red blood cells, reticulocytes, hematocrit, and haemoglobin) were repeatedly assayed during the following 2-4 weeks. The results showed that animals with cervical sympathectomy adapt in a deficient manner to hypoxia; lacking the adaptive sino-carotid reflexes, adaptation occurs through increased Epo secretion, animals with cervical sympathectomy having higher counts of reticulocytes and of red blood cells at the end of experiment than intact animals. Thoracic sympathectomy has little influence upon the erythrocytic response, as the largest part of the respiratory and circulatory sympathetic reactions occur via the cervical sympathetic nerve. Lumbar sympathectomy without removal of the celiac ganglion does not decrease the erythrocytic response as expected; on the contrary, the erythrocytic response is increased as compared to controls.

Differential chemosensory function and receptor expression of splanchnic and pelvic colonic afferents in mice

Lumbar splanchnic (LSN) and sacral pelvic (PN) nerves convey different mechanosensory information from the colon to the spinal cord. Here we determined whether these pathways also differ in their chemosensitivity and receptor expression. Using an in vitro mouse colon preparation, individual primary afferents were tested with selective P2X and transient receptor potential vanilloid receptor 1 (TRPV1) receptor ligands. Afferent cell bodies in thoracolumbar and lumbosacral dorsal root ganglia (DRG) were retrogradely labelled from the colon and analysed for P2X3- and TRPV1-like immunoreactivity (LI). Forty per cent of LSN afferents responded to alpha,beta-methylene adenosine 5'-triphosphate (alpha,beta-meATP; 1 mm), an effect that was concentration dependent and reversed by the P2X antagonist pyridoxyl5-phosphate 6-azophenyl-2',4'-disulphonic acid (PPADS) (100 microm). Significantly fewer PN afferents (7%) responded to alpha,beta-meATP. Correspondingly, 36% of colonic thoracolumbar DRG neurones exhibited P2X3-LI compared with only 19% of colonic lumbosacral neurones. Capsaicin (3 microm) excited 61% of LSN afferents and 47% of PN afferents; 82% of thoracolumbar and 50% of lumbosacral colonic DRG neurones displayed TRPV1-LI. Mechanically insensitive afferents were recruited by alpha,beta-meATP or capsaicin, and were almost exclusive to the LSN. Capsaicin-responsive LSN afferents displayed marked mechanical desensitization after responding to capsaicin, which did not occur in capsaicin-responsive PN afferents. Therefore, colonic LSN and PN pathways differ in their chemosensitivity to known noxious stimuli and their corresponding receptor expression. As these pathways relay information that may relate to symptoms in functional gastrointestinal disease, these results may have implications for the efficacy of therapies targeting receptor modulation.

Arrays for chronic functional microstimulation of the lumbosacral spinal cord

Our objective is to develop neural prostheses based on an array of microelectrodes implanted into the sacral spinal cord, that will allow persons with spinal cord injuries to regain control of their bladder and bowels. For our chronic cat model, we have developed two microelectrode arrays, one type containing nine discrete activated iridium microelectrodes and the second utilizing silicon substrate probes with multiple electrode sites on each probe. Both types can elicit an increase in the pressure within the urinary bladder of more than 40-mm Hg and/or relaxation of the urethral sphincter. A stimulus of 100 microA and 400 micros/ph at 20 Hz (charge-balanced pulses) was required to induce a large increase in bladder pressure or relaxation of the urethral sphincter. We found that 24 h of continuous stimulation with these parameters induced tissue injury (disrupted neuropil, infiltration of inflammatory cells, and loss of neurons close to the tip sites). However, a neural prosthesis that is intended to restore bladder control after spinal cord injury would not operate continuously. Thus, when this stimulus was applied for 24 h, at a 10% duty cycle (1 min of stimulation, then 9 min without stimulation) only minimal histologic changes were observed.

The sensory and sympathetic nerve supply within the cervical spine: review of recent observations

The purpose of this review is to identify recently observed features of the sympathetic and sensory systems and their pathways which characterize cervical spine innervation and their potential relevance to the clinical pain syndromes. The results of studies examining the innervation patterns of the zygoapophysial joints serve to demonstrate that structures in the cervical spine, as in other spinal regions, are partly innervated by sensory nerves traveling along sympathetic pathways. These studies also demonstrate that the neuropeptide levels in the cell bodies located within the dorsal root ganglion of these sensory nerves fluctuate according to the physiological state of the zygoapophysial joint. Additional to the sympathetic nerves accompanying the vertebral artery, the innervation patterns of dura and posterior longitudinal ligament in the upper cervical spine are distinctive features of cervical spine innervation. The possible clinical implications of cervical innervation patterns are considered with reference to referred pain, the pain patterns associated with a dissecting vertebral artery and cervicogenic headaches.

P2X3-immunoreactive primary sensory neurons innervating lumbar intervertebral disc in rats

The P2X(3) receptor is normally localized in a sub-population of small-diameter dorsal root ganglion (DRG) neurons, and is thought to be related to pain perception. The aim of this study in rats was to examine P2X(3)-immunoreactivity in DRG neurons innervating the lumbar disc and in DRG neurons innervating cutaneous tissues. Fluoro-Gold was applied to the L5-L6 disc, the plantar skin of the hind paw (L4-L5 dermatomes), and the back skin (L1-L2 dermatomes). It has been reported that the L5-L6 disc is innervated by T13-L5 DRG neurons. We performed immunostaining using antibodies against the P2X(3) receptor of T13-L5 DRGs to examine the L5-L6 disc, L4 and L5 DRGs to examine plantar skin and L1 and L2 DRGs to examine back skin. The P2X(3)-immunoreactivity was detected in 22.0 and 22.8% of neurons, labeled by Fluoro-Gold applied to plantar and back skin, respectively. However, P2X(3)-immunoreactivity was detected in only 4.0% of the neurons projecting to the L5-L6 disc. The proportion of P2X(3)-immunoreactive neurons was significantly larger in the DRG neurons innervating the plantar or the back skin, than in the DRG neurons innervating the lumbar disc. These results suggest that the P2X(3) receptors are abundant in DRG neurons innervating cutaneous tissues, but not in neurons innervating the lumbar disc. It is likely therefore that the P2X(3) receptor is less related to the mechanism of discogenic pain, than to cutaneous tissue pain.

Age-associated changes in the monoaminergic innervation of rat lumbosacral spinal cord

The effects of ageing on the innervation patterns of lumbosacral spinal nuclei involved in controlling lower urinary tract functions, including micturition, were studied using immunohistochemistry for serotonin (5-HT) and tyrosine hydroxylase (TH) in male Wistar rats of 3 and 24 months. Quantitative image analysis revealed significant age-associated declines in the innervation of most regions including the intermediolateral cell nucleus, sacral parasympathetic nucleus, dorsal grey commissure and in the ventral horn including the dorsolateral nucleus which in the rat is one of the component nuclei homologous to Onuf's nucleus in man. Notable exceptions to this generalised decline were observed in the 5-HT innervation of the sacral parasympathetic nucleus, which was maintained, and in the region of the dorsolateral motor nucleus where TH-like immunoreactivity did not significantly decline. These results suggest that the changes in micturition characteristics observed in aged rats may in part be a consequence of the alterations in, and decline of, aminergic inputs to both autonomic and somatic spinal nuclei associated with bladder function.

[Effect of apisatron in lumbar spinal cord diseases]

A therapeutic effect has been studied of the drug apizartron of the ESPARMA GmbH firm (Osterweddingen, Germany) in those patients presenting with damaged lumbar spine. The ointment apizartron has been shown to alleviate the pain syndrome and myotonic (spastic) reactions, with its effect having been somewhat less pronounced on radicular compression, neurodystrophic disorders, and on the arterial bloodflow of the inferior limbs. The drug is recommended for use in a complex therapy of vertebrogenic disorders of the lumbar spine.

Role of the sinu-vertebral nerve in low back pain and anatomical basis of therapeutic implications

Low back pain is frequent and results in major disability for patients. This anatomical study was done to understand mechanisms involved in that pain. Two kinds of innervation are present in the lumbar spine: one depends on the somatic nervous system and the other on the sympathetic nervous system. The sympathetic nerves are the sinu-vertebral nerves and the rami communicantes which innervate the intervertebral disc, the ventral surface of the dura mater, the longitudinal dorsal ligament and the longitudinal ventral ligament. The sinu-vertebral nerve was described first by Luschka in 1850. This nerve is implicated in diffuse low back pain because of its pathway and its sympathetic component. This nerve cannot directly reach a somatic element at each level of the lumbar spine, so must first reach the L2 spinal ganglion. Thus, there is a "hole" in the somatic innervation between L3 and L5 because the dorsal nerves do not reach the skin at these levels. The pain therefore takes another route through the sympathetic system. Discogenic pain is mediated by the sinu-vertebral nerves, and through the rami communicantes reaches the L2 spinal ganglion. Anatomical and clinical features reinforce this hypothesis.

Comparison of surgical and electrodiagnostic findings in single root lumbosacral radiculopathies

To identify the segmental innervation of L-2-S-1 muscles, we compared the preoperative electrodiagnostic examinations of 45 patients with single-level lumbosacral radiculopathies confirmed radiologically and surgically. The electrodiagnostic findings were classified as abnormal only by the needle examination and only if muscles demonstrated active denervation or a marked neurogenic motor unit potential firing pattern. In comparison to other surgical, intraoperative root stimulation, and clinical studies, we found several differences. Overall, there was little overlap among L-2-4, L-5, and S-1 radiculopathies. The tibialis anterior was predominantly L-5 innervated, the gastrocnemius (medial and lateral head) predominantly S-1 innervated, and the biceps femoris (short and long head) exclusively S-1 innervated. The two heads of biceps femoris were not affected in any patients with L-5 radiculopathy in whom they were examined. These findings help guide both the clinician and surgeon in the diagnosis and treatment of lumbosacral radiculopathies.

Horner's syndrome and trigeminal nerve palsy after lumbar epidural analgesia for labor and delivery

This report highlights transient Horner's syndrome and trigeminal nerve palsy following labor epidural analgesia. A 29-year-old primigravida had a lumbar epidural catheter placed for analgesia in labor. The analgesia was maintained by infusion of a dilute local anesthetic/opioid mixture and turned off after achieving complete cervical dilation. Approximately 1 hour after delivery she complained of heaviness in her left eyelid, and was noted to have left-sided ptosis and paresthesia within the distribution of the ophthalmic and maxillary divisions of the trigeminal nerve, which resolved over the next 2 hours. There were no other neurologic changes. Horner's syndrome and cranial nerve palsies can occur as a consequence of epidural analgesia for labor.