Cervical Radiculopathy

Cervical radiculopathy is a condition encountered commonly in the evaluation of neck pain that may result in significant discomfort and functional deficits. Although the long-term prognosis of this condition is favorable, a standardized approach to therapy is important to minimize unnecessary tests and identify patients who require more urgent intervention. Patient education, pain control, and physical therapy are the first line of therapy. Patients who have protracted pain or significant functional deficits may require a more thorough evaluation, including imaging, electrodiagnostic testing, and, possibly, surgical referral. This article outlines the basic clinical, diagnostic, and therapy considerations in the evaluation of cervical radiculopathy.

Sensory Receptors in the Visceral Pleura

Today, diagnosis and treatment of chest pain related to pathologic changes in the visceral pleura are often difficult. Data in the literature on the sensory innervation of the visceral pleura are sparse. The present study aimed at identifying sensory end-organs in the visceral pleura, and at obtaining more information about neurochemical coding. The immunocytochemcial data are mainly based on whole mounts of the visceral pleura of control and vagally denervated rats. It was shown that innervation of the rat visceral pleura is characterized by nerve bundles that enter in the hilus region and gradually split into slender bundles with a few nerve fibers. Separate nerve fibers regularly give rise to characteristic laminar terminals. Because of their unique association with the elastic fibers of the visceral pleura, we decided to refer to them as "visceral pleura receptors" (VPRs). Cryostat sections of rat lungs confirmed a predominant location on mediastinal and interlobar lung surfaces. VPRs can specifically be visualized by protein gene product 9.5 immunostaining, and were shown to express vesicular glutamate transporters, calbindin D28K, Na+/K+-ATPase, and P2X3 ATP-receptors. The sensory nerve fibers giving rise to VPRs appeared to be myelinated and to have a spinal origin. Because several of the investigated proteins have been reported as markers for sensory terminals in other organs, the present study revealed that VPRs display the neurochemical characteristics of mechanosensory and/or nociceptive terminals. The development of a live staining method, using AM1-43, showed that VPRs can be visualized in living tissue, offering an interesting model for future physiologic studies.

Differential control of the scapulothoracic muscles in humans

The control of the scapulothoracic muscles trapezius (Tr) and serratus anterior (SA) has been examined in normal human subjects. Electromyographic recordings were made from the SA and Tr muscles (upper trapezius UTr, lower trapezius LTr) using surface electrodes placed bilaterally. Magnetic stimulation of the motor cortex and electrical stimulation of peripheral nerves were used to examine their descending and reflex control. The average optimal site of cortical stimulation was found to be the same for SA, UTr and LTr (an approximate centre of gravity of -0.6 cm, 3.7 cm where the centre of gravity is expressed as the mean anterio-posterior position, the mean medio-lateral position). Some asymmetry in the cortical representation of UTr was found in each individual tested. Magnetic stimulation evoked bilateral MEPs in Tr (latency contralateral (c) UTr 8.5 +/- 1.6 ms, ipsilateral (i) UTr 19.0 +/- 2.7 ms) but only contralateral responses were evoked in SA (11.2 +/- 2.6 ms). Electrical stimulation of the long thoracic nerve at two sites was used to examine homonymous and heteronymous reflexes of SA, while electrical stimulation of cervical nerve of C3/4 was used to examine the heteronymous reflexes of Tr. Ipsilateral SA H reflexes were evoked at a latency of 9.9 +/- 0.8 ms (proximal site) and 10.8 +/- 1.2 ms (distal site). No group I reflexes were evoked from SA to its contralateral homologue. No group I reflexes were evoked between Tr and SA. Finally, cross-correlation of activity from the Tr muscle pairs and the SA muscle pair revealed that the motoneurones of the Tr muscles share some common presynaptic input whereas there was no detectable common presynaptic input to the SA muscle pair. This study extends and consolidates knowledge regarding the neural control of trapezius and for the first time explores the neural control of SA. The study demonstrates a contrasting bilateral control of Tr and SA. These patterns of connections are discussed in relation to the contrasting bilateral functional roles of these muscles.

Cervical spine manipulation alters sensorimotor integration: A somatosensory evoked potential study

OBJECTIVE

To study the immediate sensorimotor neurophysiological effects of cervical spine manipulation using somatosensory evoked potentials (SEPs).

METHODS

Twelve subjects with a history of reoccurring neck stiffness and/or neck pain, but no acute symptoms at the time of the study were invited to participate in the study. An additional twelve subjects participated in a passive head movement control experiment. Spinal (N11, N13) brainstem (P14) and cortical (N20, N30) SEPs to median nerve stimulation were recorded before and for 30min after a single session of cervical spine manipulation, or passive head movement.

RESULTS

There was a significant decrease in the amplitude of parietal N20 and frontal N30 SEP components following the single session of cervical spine manipulation compared to pre-manipulation baseline values. These changes lasted on average 20min following the manipulation intervention. No changes were observed in the passive head movement control condition.

CONCLUSIONS

Spinal manipulation of dysfunctional cervical joints can lead to transient cortical plastic changes, as demonstrated by attenuation of cortical somatosensory evoked responses.

SIGNIFICANCE

This study suggests that cervical spine manipulation may alter cortical somatosensory processing and sensorimotor integration. These findings may help to elucidate the mechanisms responsible for the effective relief of pain and restoration of functional ability documented following spinal manipulation treatment.

C1 lateral screws and C2 pedicle/pars screws

A variety of techniques exist for fixation of the upper cervical spine. The development of universal posterior cervical screw-rod instrumentation systems has resulted in recent interest in new and stable segmental fixation into C1 and C2. The C1 lateral mass is a safe and robust anchor point; however, the anatomic corridor to access the screw entry portal is unfamiliar. Understanding the C1 bony landmarks and the course and relationship of the soft-tissue structures (such as the vertebral artery and the C2 nerve root) is critically important. Alternative techniques for achieving segmental screw fixation into C2 are being developed. With polyaxial screw heads and lateral offset connectors, screw anchors can be driven into the most sturdy and safest aspects of C2 without concern for the position of the longitudinal rod.

The vertebral nerve revisited

There is significant paucity in the literature regarding the vertebral nerve. Moreover, descriptions of this structure are conflicting. To evaluate further the anatomy and potential clinical significance of this structure, 10 fresh adult cadavers (20 sides) underwent dissection and macroscopic observation of this structure. All specimens were found to have a vertebral nerve that originated from the stellate ganglion with the exception of two left sides (10%) in which this nerve arose from the inferior cervical ganglion. This nerve ascended posteromedial to the vertebral artery. The vertebral nerve was found to be, in essence, a long and deep gray ramus communicans that connected most commonly the stellate ganglia to C6 or C7 spinal nerves by passing through the C6 and C7 transverse foramina. Fifteen percent of sides were found to have a vertebral nerve that was plexiform in its configuration. Fifty percent were found to have very small branches that entered the fibrous capsule of adjacent zygapophyseal and intervertebral joints. Some specimens were noted to have meningeal branches of the vertebral nerve. Based on our observations, the vertebral nerve is simply a deep ramus communicans, which often provides articular and meningeal branches to the adjacent spine. As neck pain is a significant reason for physician office visits, additional knowledge of the nerves innervating the joints and adjacent meninges of the neck could be important for both surgical and medical blockade of nerve fibers.

Sensory and sympathetic innervation of cervical facet joint in rats

OBJECTIVE

To explore the patterns of innervation of cervical facet joints and determine the pathways from facet joints to dorsal root ganglions (DRGs) in order to clarify the causes of diffuse neck pain, headache, and shoulder pain.

METHODS

Forty-two male-Sprague-Dawley rats, weighing 250-300 g, were randomly divided into three groups: Group A (n=18), Group B (n=18), and Group C (n=6). Under anesthesia with intraperitoneal pentobarbital sodium (45 mg/kg body weight), a midline dorsal longitudinal incision was made over the cervical spine to expose the left cervical facet joint capsule of all the rats under a microscope. The rats in Group A underwent sympathectomy, but the rats in Group B and Group C did not undergo sympathectomy. Then 0.6 microlitre 5% bisbenzimide (Bb) were injected into the C1-2, C3-4 and C5-6 facet joints of 6 rats respectively in Group A and Group B. The holes were immediately sealed with mineral wax to prevent leakage of Bb and the fascia and skin were closed. But in Group C, 0.9% normal saline was injected into the corresponding joint capsules. Then under deep re-anesthesia with intraperitoneal pentobarbital sodium (45 mg/kg body weight), C1-C8 left DRGs in all rats and the sympathetic ganglions in Group B were obtained and the number of the labeled neurons was determined.

RESULTS

Neurons labeled with Bb were present in C1-C8 DRGs in both Group A and Group B, and sympathetic ganglions in Group B. In the C1-2 and C3-4 subgroups, labeled neurons were present from C1 to C8 DRGs, while in C5-6 subgroups they were from C3 to C8. The number of Bb(+) neurons after sympathectomy was not significantly different in the injected level from that without sympathectomy. But in the other levels, the number of Bb(+) neurons after sympathectomy was significantly less than that without sympathectomy.

CONCLUSIONS

The innervation of the cervical facet joints is derived from both sensory and sympathetic nervous system, and DRGs are associated with sympathetic ganglions through nerve fibers outside the central nerve system.

Cervical radiofrequency neurotomy in patients with chronic whiplash: a study of multiple outcome measures

OBJECT

Cervical radiofrequency neurotomy (CRFN) is used in the treatment of patients with chronic pain and disability due to whiplash injury. Confirmation of its efficiency has, however, been based solely on pain and psychological distress factors. The aim of the present study was to extend the assessment of CRFN efficacy by adding other outcome measures to shed light on neuromotor-functional-psychological interactions by undertaking comparison of pre- and 1-year postintervention data.

METHODS

Forty patients with chronic whiplash injury-associated disorders were evaluated prior to and at two separate sessions after CRFN. The evaluation included Neck Disability Index, cervical range of motion, isometric cervical muscle strength, cervical pressure pain threshold, Symptom Check List-90-Revised, and subjective Self-Report of Improvement (SRI). The authors found that the CRFN had a significantly positive effect on all measured parameters. A case-by-case analysis revealed improvement in 70% of the patients at the final follow-up examination. Using stringent cutoff values, between 30 and 60% of the patients experienced measurable improvement. Evaluation of SRI results indicated that more than 80% of the patients were satisfied with the procedure.

CONCLUSIONS

Approximately 1 year after intervention, CRFN was associated with an acceptable rate of success, as reflected by objective and subjective outcome measures.

Akute Herz-Kreislaufreaktionen bei zervikaler Spinalnervenanalgesie

AIM

The frequency of cardiovascular adverse effects of cervical nerve root infiltration was investigated by means of a prospective study.

METHOD

The hemodynamic and respiratory parameters systolic and diastolic blood pressure, heart rate, respiratory rate and oxygen saturation were monitored continuously in 56 patients undergoing cervical spine nerve root infiltration (injection of 10 ml Lidocain 0.5 %, mean depth of injection 5 cm). The monitored time frame ranged from 5 minutes before to 10 minutes after its administration, an additional holter-monitoring began 1 day prior to the injection.

RESULTS

Severe complications such as syncopes were not observed in any of the 56 patients, 4 patients developed presyncopes. None of the registered parameters showed a significant change. In a group of patients with known, pre-existing cardiovascular morbidity, no significant changes occurred either. No relevant cardiac arrhythmias were observed.

CONCLUSION

The observed cardiovascular complications were not severe. Most probably, the observed reactions were vasavagal presyncopes. Supine positioning led to immediate recovery in all of these patients. A complete hemodynamic monitoring and the placement of an intravenous line do not seem to be absolute necessities in the routine cervical nerve root infiltration.

Percutaneous Radiofrequency Neurotomy for Chronic Neck Pain: Outcomes in a Series of Consecutive Patients

BACKGROUND

Randomized controlled trials in research settings have demonstrated the efficacy of percutaneous radiofrequency neurotomy of the medial branches of the cervical dorsal rami in the palliation of chronic zygapophysial joint pain, a common cause of chronic neck pain, but one that is under-recognized in some quarters.

AIMS

This study aimed to determine the outcomes of radiofrequency neurotomy in usual clinical practice for patients with established cervical zygapophysial joint pain.

METHODS

The study was conducted in a public hospital, incorporating the private practice and public clinic elements of a single physician. All patients who underwent radiofrequency neurotomy had a diagnosis of cervical zygapophysial joint pain established by controlled cervical medial branch blocks. The primary outcome of duration of pain relief was determined for all consecutive procedures performed during a two-year period. Data were collected by chart review and telephone contact by an independent assessor.

RESULTS

Forty-seven procedures were performed on 35 patients. Two patients were lost to follow-up. Twelve patients had two procedures. Thirty-six of 45 assessable procedures (80%) achieved significant pain relief. These 36 procedures achieved a mean duration of pain relief of 36 weeks, with a median of 35 weeks. Repeat procedures usually achieved reproducible pain relief. Most patients had significant postprocedural pain for about one week. Only one serious adverse event (local superficial infection) was reported.

CONCLUSION

Radiofrequency neurotomy is an effective palliative treatment for chronic cervical zygapophysial joint pain when performed in routine clinical practice.

Neurophysiological and biomechanical characterization of goat cervical facet joint capsules

Cervical facet joints have been implicated as a major source of pain after whiplash injury. We sought to identify facet joint capsule receptors in the cervical spine and quantify their responses to capsular deformation. The response of mechanosensitive afferents in C5-C6 facet joint capsules to craniocaudal stretch (0.5 mm/s) was examined in anaesthetized adult goats. Capsular afferents were characterized into Group III and IV based on their conduction velocity. Two-dimensional strains across the capsules during stretch were obtained by a stereoimaging technique and finite element modeling. 17 (53%) Group III and 14 (56%) Group IV afferents were identified with low strain thresholds of 0.107+/-0.033 and 0.100+/-0.046. A subpopulation of low-strain-threshold afferents had discharge rate saturation at the strains of 0.388+/-0.121 (n=9, Group III) and 0.341+/-0.159 (n=9, Group IV). Two (8%) Group IV units responded only to high strains (0.460+/-0.170). 15 (47%) Group III and 9 (36%) Group IV units could not be excited even by noxious capsular stretch. Simple linear regressions were conducted with capsular load and principal strain as independent variables and neural response of low-strain-threshold afferents as the dependent variable. Correlation coefficients (R2) were 0.73+/-0.11 with load, and 0.82+/-0.12 with principal strain. The stiffness of the C5-C6 capsules was 16.8+/-11.4 N/mm. Our results indicate that sensory receptors in cervical facet joint capsules are not only capable of signaling a graded physiological mechanical stimulus, but may also elicit pain sensation under excessive deformation.

Recording of neural activity from goat cervical facet joint capsule using custom-designed miniature electrodes

STUDY DESIGN

To establish a methodology for the neurophysiologic study of mechanoreceptors in the cervical facet joint capsule.

OBJECTIVES

To test a custom designed miniature dual bipolar electrode for recording the neural activity in cervical dorsal roots. To determine if the neural activity from different receptors in the capsule can be differentiated using this methodology.

SUMMARY OF BACKGROUND DATA

Injury to cervical facet joint capsules has been regarded as an important source of whiplash pain, but no neurophysiologic study has been performed to demonstrate or characterize sensory nerve function in the capsule.

METHODS

Nineteen goats weighing 34 to 55 kg were used under general anesthesia. A C4-C6 laminectomy was performed to expose the C6 nerve root. Custom designed miniature dual bipolar electrodes were used to record neural activity in the left C6 branches. Electrical and mechanical stimuli were used to evoke receptor activity in the dorsal aspect of the C5/6 capsule. Conduction velocities (CVs) of evoked units were determined by electrical stimulation and dual-bipolar-electrode recording methods. The units were classified based on their CVs. The waveform of each classified unit was saved as a template for later single unit discharge search among multiunit discharges during the stretch of the capsule. The C5/6 facet joint with capsule was pulled by a computer-controlled actuator instrumented with a load cell at a rate of 0.5 mm per second. The evoked neural activity and load were recorded, digitized, and analyzed to determine CV, discharge rate, and response to the stretch.

RESULTS

Miniature bipolar electrodes recorded the neural activity in both channels, with single unit CVs being measured. There was no discernible motion between the electrode and dorsal root when the capsule was pulled. Both local compression and stretch on capsule evoked multiunit discharges. A-beta, A-delta, and C-fiber units were found among these multiunit discharges. The rate of single unit and multiunit discharges increased during capsule stretch in the physiologic range and afterdischarges occurred beyond the physiologic range.

CONCLUSIONS

The novel miniature electrodes not requiring a micromanipulator made it feasible and reliable to record neural activity from short cervical spinal roots. Waveforms of different units could be identified, making it possible to study sensory functions of the facet joint capsule. A-beta, A-delta, and C-fiber units were found responding to mechanical stimuli, indicating that facet joint capsule has functional proprioceptors and nociceptors.

The triangle of the vertebral artery

OBJECTIVE

Neurosurgical procedures such as proximal brachial plexus repair, scalenotomy, and direct isolation of the proximal vertebral artery require a good working knowledge of the triangle of the vertebral artery. This deep triangle of the neck is bound by the subclavian artery and the anterior scalene and longus cervicis muscles. In addition to the vertebral artery, many important structures are found in this area, such as the ganglionated sympathetic chain and certain cervical spinal nerves.

METHODS

Twenty formalin-fixed cadavers were used for this study. Dissection of this triangle was performed, and measurements were made not only of parts of its borders, but also distances from these borders to neurologically important structures within its confines, such as the C8 spinal nerve.

RESULTS

In all specimens, the middle scalene muscle was noted to form part of the posterior wall of the triangle. The mean height of the triangle was found to be 3.2 cm, and the mean width of its base was 1.3 cm. We observed that the C8 spinal nerve had a mean distance of 1.2 cm inferior to the apex of the triangle and that the C7 spinal nerve was found inside the triangle in 5% of sides. If the phrenic nerve entered the triangle, it was never found more than 6 mm medial to the anterior scalene muscle. The vertebral artery always traveled intimately along the lateral border of the longus cervicis muscle, and its lateral edge ranged 5 to 8 mm medial to the medial edge of the anterior scalene muscle.

CONCLUSION

The C7 spinal nerve was observed in the triangle of the vertebral artery. In addition, the posterior border of the triangle of the vertebral artery was clearly defined in this study, and the middle scalene muscle could be used as a landmark. These data, coupled with our quantitation of parts and structures within the triangle, may assist neurosurgeons who operate on this area of the neck.

Effect of head position and visual condition on balance control in inverted stance

This study analyzed the effect of head position and visual condition on the control of balance in handstand, a gymnastics posture that necessitates adaptation of sensory information processing. Five expert gymnasts participated. Centre of pressure trajectories and kinematics of different body segments were recorded. The gymnasts were instructed to maintain three handstands as long as possible in four head positions, with and without vision. Performances and postural stability was much better in the standard and dorsiflexion positions than in the aligned and ventroflexion positions under the two conditions of vision. Performances were lower without vision in the standard and dorsiflexion position. If vision clearly plays an important role, yet the tonic neck reflexes also seem to contribute greatly to control body sways during inverted posture.

Central motor conduction in cervical dystonia with cervical spondylotic myelopathy

OBJECTIVES

It has been known that cervical dystonia develops secondarily to spinal cord injuries as secondary dystonia. However, little is known about the pathophysiological mechanism.

PATIENTS AND METHODS

We examined motor and sensory conduction in six patients with symptomatic cervical dystonia by transcranial magnetic stimulation (TMS). All of the patients exhibited unilateral head rotation. They had symptoms corresponding to cervical myelopathy and felt discomfort in the neck, shoulders or arms before involuntary movement occurred.

RESULTS

Although the overall central motor conduction time (CMCT) was not different from that of normal controls, contralateral CMCT was significantly delayed compared to ipsilateral CMCT (p<0.05). The results of somatosensory evoked potential study demonstrated that contralateral central conduction time (CCT) was not significantly different from ipsilateral CCT.

CONCLUSION

These findings indicate that there is a selective interference with the contralateral corticospinal tract in patients with symptomatic cervical dystonia.

Selective Transfer of the C7 Nerve Root: An Experimental Study

The authors present selective C7 nerve root transfer in a rat model. The musculocutaneous nerve was neurotized by various portions of ipsilateral C7. The latent period and maximum amplitude of evoked motor action potential of the biceps, number of regenerating myelinated nerve fibers, cross-sectional area and wet weight of the biceps, and twitch and tetanic tensions of the biceps were measured at four postoperative intervals. In the early postoperative period (1 and 2 months), nerve regeneration in neurotization with the posterior division or the anterior division of C7 was significantly better than that with the anterolateral fascicles of the anterior division or the phrenic nerve. As the postoperative interval prolonged, the parameters of nerve regeneration in the latter two groups approximated those in the former two groups. This indicated that there were enough regenerating nerve fibers in the anterolateral fascicles of the anterior division and a promising potential for nerve regeneration. The clinical significance of the results lies in the design of selective C7 transfer which, using the anterolateral fascicles of the anterior division, could preserve the function of the muscles innervated by the posterior division to the greatest extent, and provide sufficient donor outflow as well. It is therefore a new option for C7 transfer.

The anatomical rationale for an upper limb sympathetic blockade: preliminary report

Stellate ganglion blockade (SGB) has long been considered pivotal in the diagnosis, determination of prognosis and management of chronic regional pain syndrome (CRPS) by sympathectomy. To date a variety of SGB techniques have been described. An inaccurate SGB may mislead clinicians and deny patients a potentially beneficial procedure. In order to obtain a predictable and readily reproducible blockade of the upper limb, a modified anterior technique was evaluated. This modified sympathetic block was performed in 10 adult cadavers (n=19 sides). Toluidine blue solution (10 ml) was injected and, following median sternotomy, the extent of spread of dye was evaluated. In one cadaver a dual block using both the modified and the standard techniques was performed. Proximal spread to the seventh cervical vertebra was noted in all blocks; distal spread extended to the neck of the third rib (n=3), neck of the fourth rib 7 (n=15) and neck of the seventh rib (n=1). Medial spread was greater than lateral spread and extended to the vertebral bodies (vagus nerve was also stained) while lateral spread in all cases "blocked" lower roots of the brachial plexus and was consistently noted beyond the usual location of the nerve of Kuntz. This modified technique demonstrated that the lower cervical ganglia and proximal thoracic sympathetic trunk were consistently stained. It should be noted that the spread was sufficiently lateral to block the nerve of Kuntz. The pitfalls of this technique aside, we suggest that this technique be reserved for therapeutic purposes, particularly when sympathectomy is not possible.

Demonstration of substance P, calcitonin gene-related peptide, and protein gene product 9.5 containing nerve fibers in human cervical facet joint capsules

STUDY DESIGN

Human cervical facet joint capsules were evaluated by immunohistochemistry.

OBJECTIVES

To study the neuropeptide innervation of the cadaveric cervical facet joint capsules.

SUMMARY OF BACKGROUND DATA

Various clinical and biomechanical studies indicate a role for cervical facet joint capsules in the etiology of neck pain. However, studies on innervation of these capsules are very limited. There is also a dearth of studies on the neuropeptide nature of this innervation.

METHODS

Facet joint capsules harvested from unembalmed cadavers were studied by the avidin biotin peroxidase method for the presence of nerve fibers. Neuropeptide innervation was investigated by using antisera to substance P and calcitonin gene-related peptide. Antisera to protein gene product 9.5 (PGP 9.5), a general neuronal marker, were also used.

RESULTS

In a study of 12 human cervical facet joint capsules, short segments of substance P were observed in 6 capsules, while fibers reactive to calcitonin gene-related peptide were demonstrated in 7 capsules. Nerve fibers immunoreactive to protein gene product 9.5 were also observed in 9 of the 14 capsules studied. Protein gene product 9.5 reactive fibers were the most extensively distributed fibers, observed as bundles and also as single fibers.

CONCLUSIONS

An abundance of protein gene product 9.5 reactive nerve fibers indicates an extensive innervation of the cervical facet joint capsules. The presence of substance P and calcitonin gene-related peptide reactive nerve fibers in a population of these lends credence to cervical facet joint capsules as a key source of neck pain.

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.

MR imaging in neuroborreliosis of the cervical spinal cord

The central nervous system is involved in 10-20% of cases in Lyme disease. The neurological symptoms, time course of the disease and imaging findings are multifaceted. We report two patients with cervical radiculitis. Magnetic resonance imaging revealed strong enhancement of the cervical nerve roots on contrast-enhanced T1-weighted images. These imaging patterns of borrelia-associated radiculitis have not been reported before. Knowledge of these imaging features may help to diagnose neuroborreliosis, which presents with non-specific symptoms.

Feedforward activity of the cervical flexor muscles during voluntary arm movements is delayed in chronic neck pain

The objective of this study was to compare onset of deep and superficial cervical flexor muscle activity during rapid, unilateral arm movements between ten patients with chronic neck pain and 12 control subjects. Deep cervical flexor (DCF) electromyographic activity (EMG) was recorded with custom electrodes inserted via the nose and fixed by suction to the posterior mucosa of the oropharynx. Surface electrodes were placed over the sternocleidomastoid (SCM) and anterior scalene (AS) muscles. While standing, subjects flexed and extended the right arm in response to a visual stimulus. For the control group, activation of DCF, SCM and AS muscles occurred less than 50 ms after the onset of deltoid activity, which is consistent with feedforward control of the neck during arm flexion and extension. When subjects with a history of neck pain flexed the arm, the onsets of DCF and contralateral SCM and AS muscles were significantly delayed ( p<0.05). It is concluded that the delay in neck muscle activity associated with movement of the arm in patients with neck pain indicates a significant deficit in the automatic feedforward control of the cervical spine. As the deep cervical muscles are fundamentally important for support of the cervical lordosis and the cervical joints, change in the feedforward response may leave the cervical spine vulnerable to reactive forces from arm movement.

Convergence of forelimb afferent actions on C7-Th1 propriospinal neurones bilaterally projecting to sacral segments of the cat spinal cord

Propriospinal neurones located in the cervical enlargement and projecting bilaterally to sacral segments of the spinal cord were investigated electrophysiologically in eleven deeply anaesthetized cats. Excitatory or inhibitory postsynaptic potentials from forelimb afferents were recorded following stimulation of deep radial (DR), superficial radial (SR), median (Med) and ulnar (Uln) nerves. 26 cells were recorded from C7, 22 from C8 and 3 from Th1 segments. The majority of the cells were located in the Rexed's laminae VIII and the medial part of the lamina VII. In 10 cases no afferent input from the forelimb afferents was found. In the remaining neurones effects were evoked mostly from DR (88%) and Med (63%), less often from SR (46%) and Uln (46%). Inhibitory actions were more frequent than excitatory. The highest number of IPSPs was evoked from high threshold flexor reflex afferents (FRA)--all connections were polysynaptic. However, inhibitory actions were often evoked from group I or II muscle afferents (polysynaptic or disynaptic) and, less frequently, from cutaneous afferents (mostly polysynaptic). Di- or polysynaptic IPSPs often accompanied monosynaptic EPSPs from group I or II muscle afferents. Disynaptic or polysynaptic EPSPs from muscle and cutaneous afferents were also recorded in many neurones, while polysynaptic EPSPs from FRA were observed only exceptionally. Various patterns of convergence in individual neuronal subpopulations indicate that they integrate different types of the afferent input from various muscle and cutaneous receptors of the distal forelimb. They transmit this information to motor centers controlling hind limb muscles, forming a part of the system contributing to the process of coordination of movements of fore--and hind--limbs.

C5 palsy after decompression surgery for cervical myelopathy: review of the literature

STUDY DESIGN

A literature review was conducted to integrate and compile available reports on postoperative C5 palsy.

OBJECTIVES

To review the clinical features, possible pathogenesis, and procedures for treatment and prevention of postoperative C5 palsy as a complication of surgery for cervical compression myelopathy.

SUMMARY OF BACKGROUND DATA

Although postoperative C5 palsy develops in approximately 5% of patients after decompression surgery of the cervical spine, its pathogenesis and the options for prevention and treatment remain unidentified and many controversies exist.

METHOD

We reviewed and analyzed papers published from 1986 to 2002 regarding C5 palsy as a postoperative complication. Statistical comparisons were made when appropriate.

RESULTS

Postoperative C5 palsy is reported to occur in an average of 4.6% of patients after surgery for cervical compression myelopathy. No significant differences were noted between patients undergoing anterior decompression and fusion and laminoplasty, nor were distinctions apparent between unilateral hinge laminoplasty and French-door laminoplasty, or between cervical spondylotic myelopathy and ossification of the posterior longitudinal ligament. Two theories were put forth to account for the pathogenesis of C5 palsy: nerve root injury and segmental spinal cord disorder. Neither of these hypotheses has been consistently supported and evidence to refute each hypothesis can be found in the literature. Recently, surgeons have advocated foraminotomy combined with laminoplasty to prevent or treat C5 palsy, but further studies into the efficacy of this procedure are needed. Although patients with C5 palsy generally have a good prognosis for neurologic and functional recovery, those with severe paralysis require significantly longer recovery times when compared to more mild cases.

CONCLUSION

The incidence of postoperative C5 palsy has been reported at 4.6% after surgery for cervical compression myelopathy and this value has not varied with different surgical procedures or disease etiologies. The pathogenesis of postoperative C5 palsy remains unclear at the present time. Patients with postoperative C5 palsy generally have a good prognosis for functional recovery, but the severely paralyzed cases required significantly longer recovery times than the mild cases.