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.

Pudendal evoked responses.

The dorsal nerve of the penis or clitoris, a branch of the pudendal nerve, was stimulated while averaged evoked responses over the spinal cord, sensory cortex, and bulbocavernosus muscle were recorded in a series of normal subjects. The morphologic features, peak latencies, and peripheral and central conduction times were compared with spinal and cortical evoked responses from the posterior tibial nerve. These tests are of potential clinical importance in the evaluation of sacral nerve root or plexus injuries and bowel, bladder, or sexual dysfunction.

The H-reflex to magnetic stimulation of lower-limb nerves.

We elicited H-reflexes by magnetic and electrical stimulation of several different nerves in 10 healthy subjects and two patients with S-1 radiculopathy. The posterior tibial nerve at the popliteal fossa and the femoral nerve at the inguinal ligament were tested with both electrical and magnetic stimulation; the proximal sciatic nerve was tested only with magnetic stimulation. Muscle activity was recorded from the soleus muscle for posterior tibial and sciatic nerve stimulation and from the vastus medialis muscle for femoral nerve stimulation. No significant difference was found between the latency of H-reflexes evoked by magnetic or electrical stimulation. With magnetic stimulation, the mean (+/- SD) Ia sensory fiber conduction velocity in the proximal segment of the sciatic nerve was 72.4 +/- 3.3 m/s, while the motor nerve fiber conduction velocity in the same portion of the nerve was significantly slower, at 60.6 +/- 2.0 m/s. In two patients with unilateral S-1 radiculopathy, the latency of the H-reflex from the soleus muscle to both magnetic and electrical stimulation of the posterior tibial nerve was absent or prolonged on the affected side. Magnetic stimulation can be used to study the H-reflex and Ia fiber conduction velocity and is particularly advantageous when testing deeply located nerve trunks.

Colonometry, cystometry, and evoked potentials in multiple sclerosis.

The conditions of three patients with advanced-stage multiple sclerosis and symptoms related to bowel and bladder function were evaluated using colonometry, cystometry, and somatosensory evoked responses from the posterior tibial nerve. The colonometrograms and cystometrograms showed notable hyperreflexia and reduced filling capacity when compared with neurologically intact patients. The neurological lesions were localized to above the conus medullaris by recording normal somatosensory responses at L-1 and abnormal responses over the scalp. This combination of tests are important in the documentation of bowel and bladder dysfunction, the localization of the neurological lesion causing the symptoms, and the determination of treatment of bowel and bladder symptoms in patients with multiple sclerosis.

Acute flaccid neonatal paraplegia: a case report.

A 3-day-old neonate became acutely and irreversibly paraplegic below L1/L2 after umbilical artery catheterization. The paraplegia was attributed to infarction of the spinal cord because of thrombosis of the artery of Adamkievicz or injection of drugs through the catheter into the spinal cord circulation. Catheterization of a more peripheral artery or placement of the umbilical catheter tip at a lower level in the aorta may prevent similar complications.

Progressive supranuclear palsy, computed tomography, and response to antiparkinsonian drugs.

Three patients with progressive supranuclear palsy demonstrated atrophy of the midbrain, pons, cerebellum, and cerebral hemispheres by computed tomography with horizontal, sagittal, and coronal reconstruction. Benztropine therapy resulted in improvement of speech and gait without significantly affecting the vertical gaze palsy.

Cortical evoked potentials on stimulation of pudendal nerve in women.

Somatosensory evoked potentials were recorded in five normal women on percutaneous stimulation of the pudendal nerve. A consistent response was obtained over the scalp 2 cm behind the Cz electroencephalographic recording site. The latency of onset of this response had a mean value of 33 msec, and the mean latency of the first positive peak was 39.6 msec. This test has potential clinical value in the evaluation of patients with bowel, bladder, or sexual dysfunction when a neurologic causation is suspected.

Continuous monitoring of bladder and urethral pressures: new technique.

A new technique for continuous monitoring of intravesical and intraurethral pressures was developed and utilized in a group of male patients to overcome the disadvantages associated with previously employed liquid and air-coupled systems. This technique permitted recording under physiologic conditions and provided information on a continuous basis concerning changes in the intravesical and intraurethral pressures in patients with multiple urologic symptoms. With further modifications this technique promises to further our understanding of the dynamics of the lower urinary tract under various conditions of stress.

Adult onset of tethered spinal cord syndrome due to fibrous diastematomyelia: case report.

Adult onset of the symptoms of tethered spinal cord is a rare entity that is occasionally associated with diastematomyelia. Only one case of fibrous diastematomyelia in an adult has been reported. The fibrous nature of this disease may present a diagnostic difficulty. A 32-year-old man with the adult onset of impairment of sacral functions with lumbar fibrous diastematomyelia is reported. Surgical release of the spinal cord was followed by improvement of the patient's function.

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.

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.

The electrodiagnostic evaluation of nerve root function.

Electrodiagnostic testing is an important part of the investigation of spinal nerve root and cord function. These tests are utilized to confirm and document suspected neuronal lesions. Characteristics of a spinal nerve root lesion, including chronicity, level, sensory or motor dysfunction, and severity, can be estimated by utilizing multiple testing procedures. Tests available include needle electromyography. H-reflexes, F-responses, bulbocavernosus reflex responses, and somatosensory evoked responses recorded over the spine and head. Each test has unique advantages and disadvantages and none can be considered of sufficient sensitivity to exclude the other tests. By using case examples the lack of correlation between electrodiagnostic testing and spinal pain has been illustrated.

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.

Cauda equina syndrome in patients undergoing manipulation of the lumbar spine.

Cauda equina syndrome has been implicated as a potential complication of spinal manipulation. A review of the literature from 1911 to 1989 revealed ten reported cases of cauda equina syndrome in patients undergoing manipulation without anesthesia. This article presents three new cases where a temporal association was found between the onset of cauda equina symptoms and lumbar manipulation. The type of manipulation administered and the relationship between the treatment and symptoms is reviewed. In each of these cases both the chiropractic practitioner and the emergency room physician failed to comprehend the nature of the problem and take appropriate action. As a consequence, the patients went untreated for several days. This may have led to residual symptomatology. It is concluded that patients who present with bowel or bladder disturbances, leg weakness, or rectal and genital sensory changes after manipulation, be recognized as experiencing a cauda equina syndrome.

Computed tomography, electrodiagnostic and clinical findings in chronic workers' compensation patients with back and leg pain.

One hundred patients with complaints of low-back pain and leg pain, consistent with a diagnosis of sciatica, were evaluated. All patients had complaints for longer than 6 months and had recently undergone electrodiagnostic testing and computed tomography (CT). Correlation was made between symptoms, straight leg raising, clinical neurological deficits, electrodiagnostic and CT findings. The radiation of pain above or below the knee and pain on straight leg raising did not show a high correlation with each other or with neurological deficits or CT findings. Electrodiagnostic studies often defined a radiculopathy in patients with equivocal clinical signs. CT findings did not predict the nature of symptoms or clinical and electrodiagnostic findings. Electrodiagnostic abnormalities showed the greatest ability to predict CT abnormalities. It is concluded that in chronic sciatica patients, no single diagnostic parameter is conclusive and a combination of clinical and laboratory findings is necessary to reach a diagnosis. In addition, many assumptions, valid in patients with acute pain cannot be extrapolated to patients with chronic sciatica.

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.

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.

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.

Back impairment and disability determination. Another attempt at objective, reliable rating.

Present disability evaluation schedules for the low back are not scientifically based and produce very great interexaminer differences. The authors have developed a new impairment schedule based on a comprehensive review of the medical literature and the collected opinions of a large number of back specialists. Tests of the new schedule show a marked decrease in interexaminer differences compared to the prior California disability rating schedule. The impairment schedule can be readily adapted to any legal system of disability rating and can be modified easily to reflect new medical knowledge. The result should be a disability rating which is more objective, more scientifically valid, and more consistent, reducing litigation, with fairness to both the low-back impaired worker and the employer.