Regional variation in survival before and after pediatric heart transplantation--an analysis of the UNOS database.

Geographic variation occurs in a variety of health outcomes. Regional influences on outcomes before and after listing for pediatric heart transplantation have not been assessed. Review of the UNOS dataset identified 5398 pediatric (≤ 18 years) patients listed for heart transplantation 2000-2011. Patients were stratified based on the region of listing. Regional-level variables were correlated with individual risk-adjusted outcomes. Mean time spent on the waitlist varied from 91.0 ± 163 days (Region 6 [R6]) to 248.1 ± 493 days (R4, p < 0.0001). Regions with more transplant centers (p < 0.0001) and fewer transplants (p = 0.0015) had higher waitlist mortality. Risk-adjusted individual waitlist mortality varied from 6.9% (R1, CI 6.2-7.8) to 19.2% (R5, CI 18.0-20.6). Waitlist mortality was higher for individuals awaiting transplant in regions with more listings per center (OR 1.04, CI 1.01-1.08) and lower in regions with more donors per center (OR 0.95, CI 0.90-0.99 per donor). Posttransplant risk-adjusted survival varied across regions (R4: 5.4%, CI 4.2-7.4; R7: 18.0%, CI 12.4-32.5), but regional variables were not correlated with outcomes. Outcomes among children undergoing heart transplantation vary by region. Factors leading to increased competition for donor allografts are associated with poorer waitlist survival. Equitable allocation of cardiac allografts requires further investigation of these findings.

The relation between the spatial distribution of vertebral artery compromise and exposure to cervical manipulation.

BACKGROUND AND PURPOSE: The vertebral artery is made up of four segments, one of which (V3) is connected to highly mobile cervical vertebrae. This connection underlies the common assumption that persons with pre-event histories of mechanical neck movements, such as cervical spine manipulation (cSMT), should experience increased V3 dissection. METHODS: Two of the largest case series of vertebral artery dissection describing subjects with and without a specific history of cSMT were reassessed to determine which segment(s) of the vertebral artery was most commonly compromised. RESULTS: The V3 segment was the most commonly involved vertebral artery segment in both the +cSMT group (e.g., V3 vs. V1 prevalence ratio (PR) = 8.46) and the -cSMT group (V3 vs. V1 PR = 4.00). However, V3 vulnerability was augmented by the effect of cSMT. The joint effect of V3 location and exposure to cSMT was greater than if each effect were simply combined. In addition,multiple site lesions were significantly more common than single sites in both the +cSMT group (PR = 2.67, p = 0.008) and the -cSMT group (PR = 2.44, p = 0.0008). CONCLUSIONS: In prior studies which identified vertebral artery compromise, those with a history of cSMT were more likely to have involvement of the V3 segment. Although this study does not identify a mechanism which relates vertebral artery dissection and exposure to cSMT, these data are compatible with a greater than additive relation between compromise of an arterial segment thought to be mechanically vulnerable and history of a mechanical event.

Cervical manipulation to a patient with a history of traumatically induced dissection of the internal carotid artery: a case report and review of the literature on recurrent dissections.

OBJECTIVE: To describe the use of rotational cervical manipulation in treating a patient who had undergone a traumatically induced dissection of the internal carotid artery and to review the literature on recurrent cervical artery dissections. CLINICAL FEATURES: A 21-year-old woman with hemiparesis from an internal carotid artery dissection that occurred as the result of a motor vehicle accident had neck pain and headaches. Moderate range of motion restrictions in the neck were present along with articular restrictions to movement palpation. INTERVENTION AND OUTCOME: After a year of soft-tissue treatment, we obtained detailed, informed consent from the patient to attempt diversified manipulation to the neck. The patient described greater and more immediate relief and longer pain-free periods than could be achieved by soft-tissue treatment alone. CONCLUSION: Patients with previous cervical artery dissections may present with unrelated neck pain and headaches and request treatment. In selected cases, with complete informed consent, manipulation of the neck may relieve these symptoms. A review of published case reports on recurrent dissections suggests that trauma is not a significant factor in the second dissection. Care must be taken in extrapolating the results from this case to any other patient with a history of cervical artery dissection.

The effects of music on cardiac patients on bed rest.

Hospitalizations that require invasive cardiac procedures or support with an intra-aortic balloon pump can be unsettling. This study was undertaken to measure the effect of a music intervention on physiologic and psychological responses of patients on bed rest due to procedural sheaths or an intra-aortic balloon pump. A randomized, two-group, pretest/post-test design was utilized to measure the effect of a 30-minute music intervention on heart rate, blood pressure, respiratory rate, skin temperature, pain perception, and mood states. One hundred forty subjects participated, 65 in the control group and 75 in the treatment group. There were no significant differences between the groups in demographic, clinical, or baseline variables, except for respiratory rate. After the music intervention, there were reductions in blood pressure, respiratory rate, and psychological distress, as measured by the Profile of Mood States (p < 0.05). Music appeared to affect selected physiologic responses and reduce psychological distress in patients on bed rest.

Cervicogenic headaches: a critical review.

BACKGROUND CONTEXT: The notion that headaches may originate from disorders of the cervical spine and can be relieved by treatments directed at the neck is gaining recognition among headache clinicians but is often neglected in the spine literature. PURPOSE: To review and summarize the literature on cervicogenic headaches in the following areas: historical perspective, diagnostic criteria, epidemiology, pathogenesis, differential diagnosis, and treatment. STUDY DESIGN/SETTING: A systematic literature review of cervicogenic headache was performed. METHODS: Three computerized medical databases (Medline, Cumulative Index to Nursing and Allied Health Literature [CINAHL], Mantis) were searched for the terms "cervicogenic" and "headache." After cross-referencing, we retrieved 164 unique citations; 48 citations were added from other sources, for a total of 212 citations, although all were not used. RESULTS: Hilton described the concept of headaches originating from the cervical spine in 1860. In 1983 Sjaastad introduced the term "cervicogenic headache" (CGH). Diagnostic criteria have been established by several expert groups, with agreement that these headaches start in the neck or occipital region and are associated with tenderness of cervical paraspinal tissues. Prevalence estimates range from 0.4% to 2.5% of the general population to 15% to 20% of patients with chronic headaches. CGH affects patients with a mean age of 42.9 years, has a 4:1 female disposition, and tends to be chronic. Almost any pathology affecting the cervical spine has been implicated in the genesis of CGH as a result of convergence of sensory input from the cervical structures within the spinal nucleus of the trigeminal nerve. The main differential diagnoses are tension type headache and migraine headache, with considerable overlap in symptoms and findings between these conditions. No specific pathology has been noted on imaging or diagnostic studies which correlates with CGH. CGH seems unresponsive to common headache medication. Small, noncontrolled case series have reported moderate success with surgery and injections. A few randomized controlled trials and a number of case series support the use of cervical manipulation, transcutaneous electrical nerve stimulation, and botulinum toxin injection. CONCLUSIONS: There remains considerable controversy and confusion on all matters pertaining to the topic of CGH. However, the amount of interest in the topic is growing, and it is anticipated that further research will help to clarify the theory, diagnosis, and treatment options for patients with CGH. Until then, it is essential that clinicians maintain an open, cautious, and critical approach to the literature on cervicogenic headaches.

Do cerebral potentials to magnetic stimulation of paraspinal muscles reflect changes in palpable muscle spasm, low back pain, and activity scores?

OBJECTIVE: Previous studies have shown that cortical-evoked potentials on magnetic stimulation of muscles are influenced by muscle contraction, vibration, and muscle spasm. This study was carried out to determine whether these potentials correlate with palpatory muscle spasm, patient symptoms, and disability in patients with low back pain. METHODS: A prospective observational study was performed on 13 subjects with a history of low back pain visiting an orthopedic hospital-based clinic. Patients were screened for serious pathologic conditions by an orthopedic surgeon. The patients were then evaluated for the presence of muscle spasm by one of the investigators who was blinded to the results of the evoked potential studies. Patients were asked to complete a low back pain visual analogue scale (VAS) and a Roland-Morris Activity Scale (RMAS). Cortical-evoked potentials were recorded with a magnetic stimulator placed over the lumbar paraspinal muscles with the patient in the prone position. The palpatory examination, VAS, RMAS, and the cortical potentials were repeated after 2 weeks of therapy commonly used to reduce muscle spasm. RESULTS: The patients demonstrated a significant decrease in low back pain VAS and RMAS scores after treatment compared with before treatment. There was a reduction in the amount of palpatory muscle spasm in 11 of 13 cases. The cortical potentials before treatment were attenuated compared with previously reported controls and showed a significant increase before and after treatment in the amplitude of these potentials with multivariate analysis of variance. There was significant correlation between the changes in cortical potentials after treatment and the changes noted in paraspinal muscle spasm and VAS and RMAS scores. CONCLUSIONS: This study confirms the previous report that the amplitude of cerebral-evoked potentials on magnetic stimulation of paraspinal muscles is depressed in the presence of palpable muscle spasm. The close correlation among these potentials, paraspinal muscle spasm, and clinical symptoms suggests that the measurement of muscle activity may be more important in the assessment of low back pain than is commonly accepted.

Neurological effects of the adjustment.

This paper discusses the several theories pertaining to the chiropractic adjustment, including the nerve compression theory, reflex theories, and pain relief theories. There is now sufficient scientific research to consider these theories reasonable working models to explain the effects of the adjustment but insufficient to consider them valid.

Risk factors and precipitating neck movements causing vertebrobasilar artery dissection after cervical trauma and spinal manipulation.

STUDY DESIGN: Potential precipitating events and risk factors for vertebrobasilar artery dissection were reviewed in an analysis of the English language literature published before 1993. OBJECTIVES: To assess the literature pertaining to precipitating neck movements and risk factors for vertebrobasilar artery dissection in an attempt to determine whether the incidence of these complications can be minimized. SUMMARY OF BACKGROUND DATA: Vertebrobasilar artery dissection and occlusion leading to brain stem and cerebellar ischemia and infarction are rare but often devastating complications of cervical, manipulation and neck trauma. Although various investigators have suggested potential risk factors and precipitating events, the basis for these suggestions remains unclear. METHODS: A detailed search of the literature using three computerized bibliographic databases was performed to identify English language articles from 1966 to 1993. Literature before 1966 was identified through a hand search of Index Medicus. References of articles obtained by database search were reviewed to identify additional relevant articles. Data presented in all articles meeting the inclusion criteria were summarized. RESULTS: The 367 case reports included in this study describe 160 cases of spontaneous onset, 115 cases of onset after spinal manipulation, 58 cases associated with trivial trauma, and 37 cases caused by major trauma (3 cases were classified in two categories). The nature of the precipitating trauma, neck movement, or type of manipulation that was performed was poorly defined in the literature, and it was not possible to identify a specific neck movement or trauma that would be considered the offending activity in the majority of cases. There were 208 (57%) men and 158 (43%) women (gender data not reported in one case) with an average age of 39.3 +/- 12.9 years. There was an overall prevalence of 13.4% hypertension, 6.5% migraines, 18% use of oral contraception (percent of female patients), and 4.9% smoking. In only isolated cases was specific vascular disease such as fibromuscular hyperplasia noted. CONCLUSIONS: The literature does not assist in the identification of the offending mechanical trauma, neck movement, or type of manipulation precipitating vertebrobasilar artery dissection or the identification of the patient at risk. Thus, given the current status of the literature, it is impossible to advise patients or physicians about how to avoid vertebrobasilar artery dissection when considering cervical manipulation or about specific sports or exercises that result in neck movement or trauma.

Low back pain: current physiologic concepts.

It is clear that low back pain is not a simple process that can be explained on purely anatomic, biomechanical, or neurophysiologic theories. The intimate relationship of these processes have to be considered. Each of the potential biomechanical stresses influence the different spinal structures in different ways, depending on the forces applied and the structure being affected. The biomechanical response to the trauma caused by these forces may be immunologic, inflammatory, or neurochemical, depending on the structures being traumatized. Once a nociceptive process is underway, it is greatly influenced by the spinal cord and the brain. Only by following this process through its various steps can a clinician begin to formulate an understanding of the mechanisms involved in the genesis of low back pain.

Soleus H-reflex to S1 nerve root stimulation.

H-reflexes in normals were elicited by percutaneous electrical and magnetic stimulation of proximal nerve roots at the cauda equina. H-M interval to S1 nerve root stimulation at the level of the S1 foramen was 6.8 +/- 0.33 ms, with side to side difference of 0.16 +/- 0.13 ms. Compression/ischemia of the sciatic nerve in the mid-thigh abolished the H-reflex to stimulation of the tibial nerve at the popliteal fossa when the H-reflex to S1 nerve root stimulation was preserved. The length of the S1 nerve root in human cadavers was measured to be 17.5 +/- 03 cm, providing an estimated dorsal root conduction velocity of 67.3 m/s and a ventral root conduction velocity of 54 m/s. We conclude that the H-M interval to S1 root stimulation can provide reliable measures of conduction within the spinal canal including proximal afferents, anterior horn cells and ventral roots.

Magnetic stimulation of muscle evokes cerebral potentials by direct activation of nerve afferents: a study during muscle paralysis.

We tested the hypothesis that magnetic stimulation of muscle evokes cerebral potentials by causing a muscle contraction that then activates muscle receptors. We measured cerebral evoked potentials accompanying magnetic stimulation of muscle in 3 patients during surgery both before and after muscle paralysis with succinylcholine, a depolarizing agent. The magnetic stimulation was at low intensity (30%) and at a 2/s rate. The administration of succinylcholine sufficient to produce muscle paralysis did not alter cerebral potentials evoked by either low-intensity magnetic stimulation of muscle (gastrocnemius/soleus) or electrical stimulation of peripheral nerve (tibial nerve). In 1 normal subject, the S1 nerve root action potentials conducting at rapid velocity (> 60 m/s) were detected at the S1 foramen with a needle electrode using electrical stimulation of the tibial nerve. However, no S1 nerve root potentials could be identified to magnetic stimulation of muscle that evoked a cerebral potential. We conclude that magnetic stimulation of muscle activates terminal afferents in the muscle to provide the afferent drive for the cerebral potentials independent of muscle contraction. The failure to detect the afferent volley in S1 nerve root to magnetic stimulation suggests that only a few afferents are activated or that the activation of afferents is temporally dispersed.

Diagnostic tests for the evaluation of back and neck pain.

The number of available diagnostic tests for patients with back and neck pain has grown dramatically over the past two decades, and their cost has increased as well. The impact of managed care and an increased understanding of the natural history of these conditions have led to close evaluation of the sensitivity and specificity of these tests and their effect on patient outcomes. Advanced anatomic and physiologic tests within the first month should be reserved for patients with red flags for serious pathologic conditions on clinical examination. Specific criteria are being developed for each electrodiagnostic and imaging test in the evaluation of the patient whose symptoms do not resolve within 1 month. Guidelines for the testing of patients with chronic back and neck pain have yet to be developed. Stronger emphasis on psychosocial issues and the assurance that pathologic progression has not been missed without the use of repetitive testing form the mainstay of diagnostic protocols in this population.

A prospective randomized three-week trial of spinal manipulation, transcutaneous muscle stimulation, massage and corset in the treatment of subacute low back pain.

STUDY DESIGN: A randomized prospective trial of manipulation, massage, corset and transcutaneous muscle stimulation (TMS) was conducted in patients with subacute low back pain. OBJECTIVES: The authors determined the relative efficacy of chiropractic treatment to massage, corset, and TMS. SUMMARY OF BACKGROUND DATA: Although all of these treatments are used for subacute low back pain treatment, there have been few comparative trials using objective outcome criteria. Patients were enrolled for a period of 3 weeks. They were evaluated once a week by questionnaires, visual analog scale, range of motion, maximum voluntary extension effort, straight leg raising and Biering-Sorensen fatigue test. The dropout rate was highest in the muscle stimulation and corset groups and lowest in the manipulation group. Rates of full compliance did not differ significantly across treatments. A measure of patient confidence was greatest in the manipulation group. RESULTS: After 3 weeks, the manipulation group scored the greatest improvements in flexion and pain while the massage group had the best extension effort and fatigue time, and the muscle stimulation group the best extension. CONCLUSION: None of the changes in physical outcome measures (range of motion, fatigue, strength or pain) were significantly different between any of the groups.

The development of guideline factors for the evaluation of disability in neck and back injuries. Division of Industrial Accidents, State of California.

This is the second article documenting the development of guideline factors for the evaluation of spine injuries by a committee supported by the Division of Industrial Accidents (DIA) in the State of California. The committee was asked to develop guidelines that incorporated cervical and thoracic spine injuries into the original guidelines developed for lumbar spine injuries (Clark et al, Spine 1988; 13:332). Multiple Independent Medical Examiners (IMEs) were requested to rate disability on 42 case reports submitted to the DIA. A tremendous variation existed in the disability rating recommended by physicians given the same set of facts. One hundred eighty-five IMEs then were asked to evaluate a series of potential factors influencing disability. Each factor was listed according to its perceived importance in determining disability. These factors then were subjected to an intensive search of the medical and scientific literature to determine their validity. A final list of 28 factors for the cervical and thoracic spine were developed and combined with the previously published factors for the lumbar spine. This led to the development of 37 factors or guidelines for the evaluation of spine disability. Testing of this schedule was performed by reviewing 159 submitted disability consultation reports. This review showed that there were no factors in the reports that were not included in the schedule. An average of 3.1 subjective factors and 2.3 objective factors were noted in the reports, with a very poor relationship between the number of factors and the level of disability given by the assessing physician. It is thought that the incorporation of the proposed guideline factors into the current disability rating system would allow for a more reproducible evaluation of disability and allow Workers' Compensation judges and administrators to make disability decisions based on documentable and reliable facts.

Paraspinal muscle evoked cerebral potentials in patients with unilateral low back pain.

Cerebral somatosensory evoked potentials (SEPs) were elicited by magnetic stimulation of paraspinal muscles unilaterally at the L2 and L5 levels in 20 healthy subjects and 16 patients with low back pain and unilateral muscle spasm. A magnetic coil with a mean diameter of 4.7 cm was placed tangentially to the skin. The stimulus strength was sufficient to induce a visible muscle twitch without producing muscle contraction in the legs. The potentials recorded over the scalp consisted of several components (P30, N40, P55, N70, and P90) and were elicited in all subjects. In both healthy and patient subjects, paraspinal muscle evoked potentials were readily elicited. Vibration applied to paraspinal muscles, as well as voluntary contraction of paraspinal muscles, was associated with attenuation of the evoked potentials. This finding suggests that muscle spindle receptors provide the afferent input responsible for the early components of the magnetically evoked cerebral potentials. In patients with unilateral muscle spasm, the amplitudes of P30-N40, N40-P50, and P50-N70 were decreased significantly on the affected side when compared with values on stimulation of the unaffected side, as well as those obtained from control subjects. The cerebral evoked potentials returned to normal amplitude when the muscle spasm subsided following a period of time and after the application of spinal manipulative therapy. The technique has potential for quantitative evaluation of muscle spasm in low back pain.