The morphological stenosis pattern of the suprascapular notch is revealed yielding higher incidence in the discrete type and elucidating the inevitability of osteoplasty in horizontally oriented stenosis

PURPOSE

To identify the morphological patterns of suprascapular notch stenosis.

METHODS

Suprascapular notch space capacity was assessed by morphometric analysis of 333 dry scapulae. Suprascapular notch parameters-superior transverse distance, middle width, depth, medial border length and lateral border length-were measured. The probable suprascapular notch stenosis was referenced by (1) comparing each obtained parameter measurement to the range of the suprascapular nerve diameter, and (2) quantifying the reduced parameters. Finally, the morphological pattern was determined based on the collective reduction of the parameters and their alignments.

RESULTS

Five types of suprascapular notch based on depth to superior transverse distance ratio were identified and assessed. Type-I showed low incidence of stenosis (6/333) and low frequency within type (6/28) with potential risk of horizontal compression. Type-II showed relatively low incidence of stenosis (9/333) and low frequency within type (9/50) with undetermined pattern. Type-III showed relatively higher incidence of stenosis (47/333) but low frequency within type (47/158) with potential risk of vertical compression. Type-IV (foramen) showed low incidence of stenosis (6/333) and relatively lower frequency within type (6/26) with potential risk of encircled compression. Finally, type-V (discrete) showed relatively high incidence of stenosis (40/333) and high frequency within type (40/71) with potential risk of vertical compression. The suprascapular notch was found to be stenosed beyond its capacity to accommodate the suprascapular nerve in 49/333. Type-V is at most risk followed by Type-III.

CONCLUSIONS

Suprascapular notch stenosis takes three morphological patterns: horizontal, vertical or mixed. An osteoplasty of suprascapular notch margins may be required beside the common surgical approach of the superior transverse scapular ligamentectomy.

Load Carriage-Related Paresthesias (Part 2): Meralgia Paresthetica

This is the second of a two-part series addressing symptoms, evaluation, and treatment of load carriage- related paresthesias. Part 1 addressed rucksack palsy and digitalgia paresthetica; here, meralgia paresthetica (MP) is discussed. MP is a mononeuropathy involving the lateral femoral cutaneous nerve (LFCN). MP has been reported in load carriage situations where the LFCN was compressed by rucksack hipbelts, pistol belts, parachute harnesses, and body armor. In the US military, the rate of MP is 6.2 cases/10,000 personyears. Military Servicewomen have higher rates than Servicemen, and rates increase with age, longer loadcarriage distance or duration, and higher body mass index. Patients typically present with pain, itching, and paresthesia on the anterolateral aspect of the thigh. There are no motor impairments or muscle weakness, because the LFCN is entirely sensory. Symptoms may be present on standing and/or walking, and may be relieved by adopting other postures. Clinical tests to evaluate MP include the pelvic compression test, the femoral nerve neurodynamic test, and nerve blocks using lidocaine or procaine. In cases where these clinical tests do not confirm the diagnosis, specialized tests might be considered, including somatosensory evoked potentials, sensory nerve conduction studies, high-resolution ultrasound, and magnetic resonance imaging. Treatment should initially be conservative. Options include identifying and removing the compression if it is external, nonsteroidal inflammatory medication, manual therapy, and/or topical treatment with capsaicin cream. Treatments for intractable cases include injection of corticosteroids or local anesthetics, pulsed radiofrequency, electroacupuncture, and surgery. Military medical care providers may see cases of MP, especially if they are involved with units that perform regular operations involving load carriage.

Focal and entrapment neuropathies

Of the many patterns of peripheral nerve disorders in diabetes mellitus (DM), isolated clinical involvement of single nerves, though less common than distal symmetric polyneuropathy and perhaps polyradiculoneuropathy, constitute an important collection of characteristic syndromes. These fall into four anatomical regions of the body: cranial, upper limb, truncal, and lower limb territories. Each of these groups of mononeuropathies has its own ensemble of epidemiologic patterns, clinical presentations, laboratory and radiologic findings, differential diagnosis, management principles and prognosis.

Degenerative Pathways of Lumbar Motion Segments--A Comparison in Two Samples of Patients with Persistent Low Back Pain

Background

Magnetic resonance imaging (MRI) is used to identify spinal pathoanatomy in people with persistent low back pain. However, the clinical relevance of spinal degenerative MRI findings remains uncertain. Although multiple MRI findings are almost always present at the same time, research into the association with clinical outcomes (such as pain) has predominantly focused on individual MRI findings. This study aimed to: (i) investigate how multiple MRI lumbar spine findings cluster together within two different samples of patients with low back pain, (ii) classify these clusters into hypothetical pathways of degeneration based on scientific knowledge of disco-vertebral degeneration, and (iii) compare these clusters and degenerative pathways between samples.

Methods

We performed a secondary cross-sectional analysis on two dissimilar MRI samples collected in a hospital department: (1) data from the spinal MRI reports of 4,162 low back pain patients and (2) data from an MRI research protocol of 631 low back pain patients. Latent Class Analysis was used in both samples to cluster MRI findings from lumbar motion segments. Using content analysis, each cluster was then categorised into hypothetical pathways of degeneration.

Results

Six clusters of MRI findings were identified in each of the two samples. The content of the clusters in the two samples displayed some differences but had the same overall pattern of MRI findings. Although the hypothetical degenerative pathways identified in the two samples were not identical, the overall pattern of increasing degeneration within the pathways was the same.

Conclusions

It was expected that different clusters could emerge from different samples, however, when organised into hypothetical pathways of degeneration, the overall pattern of increasing degeneration was similar and biologically plausible. This evidence of reproducibility suggests that Latent Class Analysis may provide a new approach to investigating the relationship between MRI findings and clinically important characteristics such as pain and activity limitation.

Prevalence and Associated Factors of Neurovascular Contact in Patients With Hemifacial Spasm

PURPOSE

This study aimed to observe the prevalence and associated factors of neurovascular contact hemifacial spasm (HFS).

DESIGN

This was a cross-sectional analytical study.

METHODS

Medical records of patients with HFS in a neuro-ophthalmology clinic in Thailand between June 2008 and June 2012 were reviewed. A positive magnetic resonance imaging finding was defined as an adjacent variant vessel that directly compressed or placed pressure on the affected facial nerve. Prevalence and associated factors were analyzed.

RESULTS

A total of 60 participants were enrolled, composed of 12 male patients and 48 female patients with a median age of 54 years [interquartile range (IQR), 44.0-64.75] and a disease duration ranging from 4 months to 16 years (median, 2 years; IQR, 1.0-6.0). The prevalence of neurovascular contact HFS was 41.7%. Neurovascular contact HFS was more prevalent among women, with an overall ratio of 3.33. In age group analysis, the prevalence was higher among older patients. In univariate analysis, right-sided symptoms and diabetes mellitus were statistically significant in their association with neurovascular contact HFS (P = 0.040 and P = 0.029, respectively). Right-sided symptoms were significant in a multiple logistic regression analysis (P = 0.038), with an odds ratio of 3.30 [95% confidence interval (CI), 1.07-10.15]. Diabetes mellitus was not statistically significant (P = 0.051), with an odds ratio of 9.99 (95% CI 0.99-96.34).

CONCLUSIONS

The prevalence of neurovascular contact in patients with HFS was 41.7%. Right-sided symptoms were significantly associated with this condition.

Intra- and inter-examiner variability in performing Tinel's test

PURPOSE

The Tinel sign was adopted in the early 1950s to detect sites of nerve compression. There have been few attempts to standardize how one elicits Tinel's sign. The goal of this study was to evaluate intra- and inter-examiner variability in the force generated using different techniques to elicit Tinel's sign.

METHODS

Nine clinicians, consisting of 3 experienced hand and peripheral nerve surgeons, 3 junior hand and peripheral nerve surgeons, and 3 surgeons in training were included in the study. Three different Tinel-type maneuvers were evaluated: (1) striking the load cell using the dominant middle finger only ("single-finger strike"), (2) using the dominant index and middle finger together ("double-finger strike"), and (3) preloading with the nondominant thumb and then striking the thumb with the dominant middle finger ("preload"). Test subjects were instructed to use their customary range of force during the testing. Each subject performed 3 sets of 5 strikes per technique.

RESULTS

There was a significant difference in nearly all subjects between the range of force generated with single- or double-finger techniques and preload technique. There was also a difference in nearly all subjects when comparing the range of forces using the single-and double-finger techniques. In addition, there were large differences in the range of forces produced by the examiners for each technique.

CONCLUSIONS

There is no standardization for eliciting the Tinel sign. This study demonstrates considerable intra- and inter-examiner differences in the range of forces generated by the different Tinel's techniques that are used in clinical practice. This variability might explain clinical differences between examiners in the ability to obtain a Tinel sign in a patient and might explain the inconsistency of sensitivity and specificity reported for Tinel's sign. Further research on standardization is needed, and future study protocols using Tinel's sign should take these findings into account.

The incidence and anatomical features of the McKenzie branch: a cadaver study

AIM

The aim of this study was to demonstrate the morphological characteristics of the connections between the spinal accessory nerve and the anterior root of the first cervical nerve (C1) which is also called the McKenzie branch.

MATERIAL AND METHODS

The cranial cervical regions of 49 specimens from 27 human cadavers were used for this study under an operating microscope. The topographical relationship of the accessory nerve to the anterior roots of C1 were studied.

RESULTS

One cadaver had a connection branch (McKenzie branch) on both sides.

CONCLUSION

The knowledge of the anatomy of these connections may help the clinician in determining treatments and surgical approaches in this anatomical area.

[Current views on the treatment of upper limb compression neuropathies]

The article presents current views about upper limb neuropathies, their treatment and clinical manifestations. The following conditions are described: carpal tunnel syndrome(CTS), cubital tunnel syndrome(CUTS), radial tunnel syndrome, and posterior nervus interosseus syndrome.

Long term results of radial tunnel release – the effect of co-existing tennis elbow, multiple compression syndromes and workers' compensation

SUMMARY

Surgical decompression of radial tunnel syndrome (RTS) remains controversial because the results are unpredictable. This study is a retrospective analysis of the long term outcomes of RTS release and a comparison of our findings with previous studies. Thirty-three extremities in 31 patients underwent decompression for radial tunnel syndrome between 1994 and 2003, of which 27 extremities in 25 patients were available for long term follow up after an average of 57 months (range 16 to 106 months). Outcomes were evaluated using the criteria of Ritts et al. (1987). For 16 patients (18 of 27 extremities), the outcome was rated as good (67%), for four patients (four extremities) as fair (15%), and for five patients (five extremities) as poor (18%). The outcome was better in patients with simple RTS (86% good results) compared with patients with additional nerve compression syndromes (57% good results), or patients with coexisting lateral epicondylitis (70% vs 43% good results), or patients who were receiving workers' compensation (73% vs 58% good results). One-third of patients still had moderate or severe disability which affected their ability to work, but 82% had relief of their pain. Surgical decompression is therefore beneficial for simple RTS, but may be less successful if there are co-existing additional nerve compression syndromes or lateral epicondylitis or if the patient is receiving workers'compensation.

Brachial plexus lesions after backpack carriage in young adults

Carrying a heavy backpack exerts compression on shoulders, with the potential to cause brachial plexopathy. We evaluated the incidence and predisposing factors of compression plexopathy of the shoulder region in 152,095 military conscripts, hypothesizing that a low body mass index and poor physical fitness predispose to the plexus lesion. Reports of conscripts with neural lesions of the upper arm associated with load carriage were reviewed retrospectively for details associated with the condition onset, symptoms, signs, nerve conduction studies, and electromyographic examinations. Height, weight, and physical fitness scores were obtained from their military training data. The incidence of neural compression after shoulder load carriage in Finnish soldiers was 53.7 (95% confidence interval, 39.5-67.8) per 100,000 conscripts per year. The long thoracic nerve was affected in 19, the axillary nerve in 13, the suprascapular nerve in seven, and the musculocutaneous nerve in six patients. Four patients (7%) had hereditary neuropathy with susceptibility to pressure palsies (HNPP). Symptoms were induced by lighter loads in patients with HNPP. Vulnerability to brachial plexopathy was not predictable from body structure or physical fitness level. To prevent these lesions, awareness of the condition and its symptoms should be increased and backpack designs should be improved.

Isolated teres minor atrophy: manifestation of quadrilateral space syndrome or traction injury to the axillary nerve?

This article prospectively determines through magnetic resonance imaging (MRI) the incidence of isolated teres minor atrophy and its gender and age distribution, and documents associated findings related to the rotator cuff, labroligamentous complex, and quadrilateral space. Two hundred seventeen consecutive shoulder MRI examinations performed over a 3-month period were prospectively reviewed and evaluated for isolated teres minor atrophy. Twelve (5.5%) patients had non-compressive isolated teres minor atrophy. Ninety-two percent (n=11) of these patients had rotator cuff or labroligamentous complex tears. No patients had an associated mass within the quadrilateral space. The average patient age was 60 years and 11 of the 12 patients were male. Isolated teres minor atrophy on MRI is most commonly seen in older patients who do not fit the expected clinical presentation of quadrilateral space syndrome. The anatomical relationship of the teres minor nerve to the joint capsule and the frequency of associated shoulder injuries in these patients raises the possibility of an association between humeral decentering and teres minor atrophy. Quadrilateral space syndrome would appear to be a very rare cause of isolated teres minor atrophy.

Upper extremity mononeuropathy among engineers

OBJECTIVES

The objectives of this study were to estimate the prevalence of mononeuropathy at the wrist among engineers who use computers and to identify associated risk factors.

METHODS

This is a cross-sectional study of 202 engineers using questionnaires and electrophysiological nerve testing. The definition for median or ulnar mononeuropathy required the combination of distal upper extremity discomfort and abnormal distal motor latency.

RESULTS

The prevalence of neuropathy at the wrist among engineers was 10.3% (right median), 3.4% (left median), 1.8% (right ulnar), and 2.9% (left ulnar). Logistic regression analysis identified three variables with positive associations (body mass index, hours of computer use, and antihypertensive medication) and three variables with negative associations (typing speed, driving hours, total break time).

CONCLUSIONS

Mononeuropathies at the wrist occur among computer-using engineers and are related to a number of factors, including hours of computer use.

Screening of neuropathic pain components in patients with chronic back pain associated with nerve root compression: a prospective observational pilot study (MIPORT)

OBJECTIVE

Chronic back pain is characterized by a combination of neuropathic and nociceptive mechanisms of pain generation. The prevalence of the neuropathic pain component is unknown. Thus, in the context of an explorative study, we aimed to determine the prevalence of signs and symptoms indicating neuropathic pain in adult patients treated by orthopaedists. We also aimed to assess the usefulness of handheld computers (PDAs) in data collection.

METHODS

Prospective epidemiological study in 18 orthopaedic practices or centres throughout Germany. Physician and patient questionnaires (paper/pencil or on handheld computers, PDAs) for patients with back pain of at least 3 months in duration were applied, as well as the von Korff score to assess pain intensity (visual analogue scale, VAS; 0 = no pain, 10 = worst possible pain) and pain characteristics, the Hannover Functional Ability Questionnaire (FFbH-R), and if patients agreed to provide information, the short-form Patient Health Questionnaire (PHQ-D) for depression.

RESULTS

For 717 patients, both patient and physician questionnaires were available. Mean patient age was 56 years; pain was predominantly located in the low back (87%). Median current pain intensity on the VAS was 5.0. Confirmed key signs and symptoms indicated neuropathic pain was frequent, e.g. radicular pain radiating beyond the knee towards the foot (40.0%), positive Lasegue sign (18.4%), or absent patellar reflex (17.3%). A third of all patients (33.5%) had >or=3 characteristic signs for neuropathic pain. Patient functionality was severely reduced (median 43.3%). There were no relevant differences in outcomes between patients using the paper/pencil method (47%) versus those preferring PDAs (53%).

CONCLUSION

Screening for neuropathic pain in this setting is feasible with simple questionnaires and scales on PDAs. Neuropathic pain is a major contributor to chronic back pain and a frequent component in patients seen by orthopaedists. At least one third of all patients should undergo additional diagnostic measures to confirm the cause of neuropathic pain.

Incidence of common compressive neuropathies in primary care

Apart from carpal tunnel syndrome, there are no population based studies of the epidemiology of compressive neuropathies. To provide this information, new presentations of compressive neuropathies among patients registered with 253 general practices in the UK General Practice Research Database with 1.83 million patient years at risk in 2000 were analysed. The study revealed that in 2000 the annual age standardised rates per 100 000 of new presentations in primary care were: carpal tunnel syndrome, men 87.8/women 192.8; Morton's metatarsalgia, men 50.2/women 87.5; ulnar neuropathy, men 25.2/women 18.9; meralgia paraesthetica, men 10.7/women 13.2; and radial neuropathy, men 2.97/women 1.42. New presentations were most frequent at ages 55-64 years except for carpal tunnel syndrome, which was most frequent in women aged 45-54 years, and radial nerve palsy, which was most frequent in men aged 75-84 years. In 2000, operative treatment was undertaken for 31% of new presentations of carpal tunnel syndrome, 3% of Morton's metatarsalgia, and 30% of ulnar neuropathy.

[Compression neuropathy of upper limbs in miners]

The authors analyzed prevalence of individual types of upper limb compression neuropathy in miners of coal and iron-ore mines. Medical examination covered main mining occupations exposed to suchhazards as local vibration, cooling microclimate, functional overstrain. Some types of compression neuropathies appeared to depend on duration of exposure to the hazards and on the occupation hands disease stage.

Quadrilateral Space Syndrome: Incidence of Imaging Findings in a Population Referred for MRI of the Shoulder

OBJECTIVE

The purpose of this study was to determine the incidence of MRI findings suggesting quadrilateral space syndrome in a population referred for shoulder MRI.

CONCLUSION

Focal teres minor atrophy or abnormal signal suggesting quadrilateral space syndrome is an uncommon, although not rare, finding on MRI of the shoulder in our referral population and is rarely an isolated abnormality.

Trigeminal neuralgia is caused by maxillary and mandibular nerve entrapment: Greater incidence of right-sided facial symptoms is due to the foramen rotundum and foramen ovale being narrower on the right side of the cranium

Trigeminal neuralgia (TN) is the most important disease of the trigeminal nerve. Vascular compression of the dorsal root of the trigeminal nerve by aberrant loop of blood vessels is currently accepted as the most common cause of TN. The right side of the face is affected by TN twice as often as the left side, but there are no anatomical reasons for the blood vessels loop to be more frequent on the right side of the cranial fossa. Additionally, vascular compression in asymptomatic patients and in TN patients without aberrant blood vessels has been reported, thereby arguing against the idea that vascular compression alone is responsible for TN. Anatomical and radiological studies have shown that the rotundum and ovale foramens on the right side of the human cranium are significantly narrower than on the left side. The rotundum and ovale foramens are crossed by the maxillary and mandibular nerves, respectively, and are the nerves most affected in TN. Based on demographic and epidemiological data of TN patients, and on anatomical findings in the foramens, we hypothesized that entrapment of the maxillary and mandibular nerves when they cross the ovale and rotundum foramens is a primary cause of TN and accounts for the higher incidence of TN on the right sided.

Peripheral Nervous System Injuries in Sport and Recreation

Many sports are associated with a variety of peripheral nervous system (PNS) injuries specific to that sport. A systematic review of sport-specific PNS injuries has not been attempted previously, and will assist in the understanding of morbidities and mortality associated with particular sporting activities, either professional or amateur. A systematic review of the literature using PubMed (1965-2003) was performed examining all known sports and a range of possible PNS injuries attributable to that sport. Numerous sporting activities (53) were found to have associated PNS injuries. The sports most commonly reported with injuries were football, hockey, soccer, baseball and winter activities. There are a number of sporting activities with injuries unique to the individual sport. This review should be of assistance for the neurologist, neurosurgeon, orthopaedic surgeon, physiatrist, sports medicine doctor, athletic trainer and general physician in contact with athletes possessing neurological injuries.

Pronator syndrome: a retrospective study of median nerve entrapment at the elbow in female machine milkers

Pronator syndrome (median nerve entrapment at the elbow) is a rare condition, but it is more common among women than men. A long-term retrospective follow-up study evaluating the outcome of surgical release of the median nerve for female machine milkers has never been carried out before, nor has a long-term study of non-treated female milkers with pronator syndrome. In the present study, two groups of machine milkers (surgical and non-surgical) were compared. The clinical examination focused on two parameters: focal tenderness and individual muscle strength. The results showed that the surgical group had no focal tenderness on palpation over the median nerve at the elbow and no selective weakness in the muscles examined, as compared to what was found before surgery. In the non-surgical group, focal tenderness was found in 12 out of 14, and 10 out of 14 showed the same weakness as in an earlier examination. While this study has limitations in sample size, surgical release of the median nerve at the elbow level, in cases of pronator syndrome, appears to provide an immediate as well as long-term return to normal strength of FPL and FDP II, along with a significant improvement in subjective status. In the non-surgical group, spontaneous improvement of the strength of FPL and FDP II was found in only four out of the 14 cases.

The lumbosacral junction in working german shepherd dogs -- neurological and radiological evaluation

The clinical and radiological incidence of lumbosacral (LS) disease was studied on 57 German Shepherd dogs (GSDs) used in active service. The study included a clinical history, a neurological examination, and plain radiographs of the caudal lumbar vertebrae. The neurological examinations revealed lower back pain and/or neural deficits in 21 dogs, of which 14 had a history of pain or pelvic gait abnormalities. Radiographic findings were spondylosis at L7-S1, degeneration of L7-S1 disc, LS malalignment, transitional LS vertebrae and/or primary spinal canal stenosis in 15 dogs with neurological abnormalities and/or back pain and in 18 dogs with no clinical signs. No correlation between the neurological and the radiographic findings were found. This study demonstrates that even prominent radiographic LS abnormalities are of minimal value in the evaluation of LS disease in the GSD.

[Lumbar nerve root compression--results of the quality assurance study 1993-1998]

Summary. This multicenter quality assurance study investigated 14 334 cases with lumbar nerv root compression between 1993 and 1998. Patient data, diagnostics, therapy and course as well as neurological status pre- and posttreatment have been investigated for each year. There was an obvious growing number of patients between 60 and 79 years of age, who have been operated. The rate raised from 20% to 28%. Age, comorbiditiy and complication rate as well as length of stay showed a positive correlation. Outpatient CTscan lost diagnostic importance (82% --> 65%) compared to MRI (16% --> 41%). Myelography regained interest in only conservatively treated patients due to difficult indication assessment (40% --> 64%). The rate of intraoperative antibiotics rose from 42% to 59% without change of infection rate. Intra- and postoperative complication rates came down from 5.6% to 2.1% and 6.9% to 1.8% respectively. Pre- and postoperative neurological findings remained unchanged.

Is the root entry/exit zone important in microvascular compression syndromes?

OBJECTIVE

Microvascular compression syndromes such as trigeminal neuralgia, hemifacial spasm, and disabling positional vertigo involve an artery or vein compressing a cranial nerve. A cranial nerve is composed of a central nervous system (CNS) segment and a peripheral nervous system (PNS) segment separated by the root entry/exit zone (REZ). Although vascular compression can occur at any point along the cranial nerve, it has been generally assumed that only vascular contact at the REZ of the affected cranial nerve can cause symptoms. On the basis of personal surgical experience, we propose that vascular compression of the CNS segment alone causes symptoms. This has important repercussions for the future diagnosis and treatment of microvascular compression syndromes, especially the cochleovestibular compression syndrome.

METHODS

For the anatomic study, four autopsy specimens and one surgical biopsy specimen of the vestibulocochlear nerve were microscopically and ultramicroscopically analyzed for structural differences between the CNS and PNS segments. For the clinical study, five patients with the clinical picture of cochleovestibular compression syndrome were treated by microsurgical decompression at the level of the CNS segment and not the REZ. One patient underwent reoperation for recurrent symptoms 4 years later, and a 4-mm vestibular neurectomy was performed at that stage. We performed an epidemiological analysis to demonstrate that the known incidences of trigeminal neuralgia, hemifacial spasm, and glossopharyngeal neuralgia are related to the length of their respective CNS segments.

RESULTS

Histological differences between the PNS and CNS segments suggest that the PNS segment is more resistant to compression. This was confirmed by neurophysiological data from intraoperative monitoring in posterior fossa surgery and experimental studies. We found a clear epidemiological correlation between the length of the CNS segment, which differed among cranial nerves, and the incidence of the microvascular compression syndrome. Successful decompression of the CNS segment in patients without compression at the REZ of the vestibulocochlear nerve for disabling positional vertigo provides clinical support for this hypothesis.

CONCLUSION

The evidence we present supports the hypothesis that vascular compression syndromes arise from vascular contact along the CNS segment of the cranial nerves.

Neurovascular contact and blood pressure response in young, healthy, normotensive men

BACKGROUND

Neurovascular contact (NVC) of the left rostral ventrolateral medulla has been implicated in the pathogenesis of "essential" hypertension, and recent studies suggest that this anomaly may be genetically determined. We therefore assessed the prevalence of this vascular anomaly in young normotensive volunteers. We also studied blood pressure, heart rate reactivity, and changes in baroreflex sensitivity in response to mental and physical stress in a subset of subjects with positive and negative brainstem findings.

METHODS

Magnetic resonance imaging of the brainstem was performed in 113 young (aged 25 +/- 8 years), normotensive male volunteers. Baroreflex sensitivity was then assessed in 13 subjects with positive brainstem findings and 20 subjects with negative findings.

RESULTS

Left-sided NVC was found in 19 subjects. Blood pressure levels, heart rate, and baroreflex sensitivity were similar in all groups. However, modulation of baroreflex sensitivity was reduced under mental and physical stress in subjects with a positive finding for NVC. Subjects with a positive finding also had a significantly lower body mass index than those with a negative finding.

CONCLUSIONS

Left-sided NVC is present in approximately one-fifth of young normotensive men, and may modulate the baroreceptor reflex under stress in these individuals.

The prevalence and characteristics of nerve compression symptoms in the general population

The purpose of this cross-sectional study was to evaluate the prevalence and intensity of nerve compression symptoms and to estimate the prevalence of carpal tunnel syndrome (CTS) in the general population. A survey that included the Katz hand diagram, the Carpal Tunnel Instrument (CTI), and the Short Form-36 questionnaire was sent to 1,559 people. A short telephone survey was conducted to a random sample of 110 nonresponders to determine if they were systematically different from the responders. Of the responders 35.1% had a symptom severity (CTI subscale) score of > or =1.5. Of the responders and the nonresponders 23.2% and 14.5%, respectively, reported waking at least once per night with numbness; 37.3% of the responders and 33.6% of the nonresponders experienced pain in the hand at least once per day. As determined by the Katz hand diagrams, 58 (16.3%) of the responders had classic or probable distributions of symptoms (likely to have CTS) and 298 (83.7%) had possible and unlikely distributions. After correcting for nonresponders our lowest possible estimate of CTS prevalence in the general US population is 3.72%, indicating a larger pool of symptomatic people than previously reported.

Persistent brachial plexus birth palsies

Sixty-six brachial plexus palsies in 64 patients were retrospectively reviewed at the San Francisco Unit of the Shriners Hospital system in a 15-year period from 1973 to 1988. All patients were referred with persistent brachial plexus palsies caused by birth trauma. The distribution of palsies at birth included 34 upper palsies, three lower palsies, and 29 mixed (or global) palsies. At final follow-up, the distribution of palsies had shifted and included 42 upper palsies, 6 lower palsies, and 14 mixed (or global) palsies. One patient had a persistent flail upper extremity. Many previously documented obstetrical risk factors were confirmed. Time to resolution or plateau averaged 4.5 months (range 3 weeks to 18 months). Only two palsies (one patient) resolved completely with time.

Occupational risk factors for radial tunnel syndrome in industrial workers

OBJECTIVES

The aim of the study was to evaluate both nonoccupational and occupational factors associated with radial tunnel syndrome (RTS) among industrial workers in 3 large plants.

METHODS

Twenty-one cases of RTS were compared with 21 referents matched for gender, age, and plant. RTS was associated with carpal tunnel syndrome (CTS) in 9 cases. Past medical history, household activities, and ergonomic and organizational characteristics of the job were analyzed.

RESULTS

The study found 3 occupational risk factors for RTS. Exertion of force of over 1 kg [odds ratio (OR) 9.1, 95% confidence interval (95% CI) 1.4-56.9] more than 10 times per hour was the main biomechanical risk factor. Prolonged static load applied to the hand during work was strongly associated with RTS (OR 5.9, 95% CI 1.2-29.9). Work posture with the elbow fully extended (0-45 degrees) was associated with RTS (OR 4.9, 95% CI 1.0-25.0). Full extension of the elbow, associated with a twisted posture of the forearm, stressed the radial nerve at the elbow. However, personal activities, household chores, and sport and leisure activities were not associated with RTS.

CONCLUSIONS

The study confirms that RTS occurs in workers performing hard manual labor that requires forceful and repetitive movements involving elbow extension and forearm prosupination.

On the incidence, cause, and prevention of recurrent laryngeal nerve palsies during anterior cervical spine surgery

STUDY DESIGN

A retrospective review of contemporaneously acquired clinical data supplemented by experimental cadaver dissection.

OBJECTIVE

To establish the incidence and mechanism of vocal cord paralysis after anterior cervical spine surgery and to determine whether controlling for endotracheal tube (ET)-laryngeal wall interactions induced by the cervical retraction system could decrease the rate of paralysis.

SUMMARY OF BACKGROUND DATA

Vocal cord paralysis is the most common otolaryngologic complication after anterior cervical spine surgery. However, the quoted frequency of this varies considerably, and the cause of the injury is not clearly defined. As a result, various, and at times contradictory, recommendations to prevent this are presented without data to support their effectiveness.

METHODS

Data gathered at the time of surgery and during follow-up visits on 900 consecutive patients who underwent anterior cervical spine surgery with plating during a 12-year interval were entered into a computerized database and reviewed for complications and procedural risk factors. After the first 250 cases an intervention consisting of monitoring ET cuff pressure and release of pressure after retractor replacement or repositioning was used, which allowed the ET to recenter within the larynx. The ET-laryngeal wall relation also was studied in fresh intubated cadavers using videofluoroscopic images, before and after retractor placement.

RESULTS

Thirty incidences of vocal cord paralysis consistent with recurrent laryngeal nerve (RLN) injury were identified: 27 temporary and 3 permanent. The rate of temporary paralysis decreased from 6.4% to 1.69% (P = 0.0002) after institution of the described maneuver. The findings confirmed that the retractor displaced the larynx against the shaft of the ET, allowing impingement on the vulnerable intralaryngeal segment of the RLN.

CONCLUSIONS

The most common cause of vocal cord paralysis after anterior cervical spine surgery is compression of the RLN within the endolarynx. Monitoring of ET cuff pressure and release after retractor placement may prevent injury to the RLN during anterior cervical spine surgery.

Can a battery of functional and sensory tests corrobrate the sensorineural complaints of subjects working with vibrating tools?

OBJECTIVES

The objective of the present paper is to study the relationship between the early sensorineural symptoms, classified according to the Stockholm scale, and the results of the main functional and sensory tests described in the literature, in subjects working with vibrating tools.

METHODS

Three groups of male workers were selected from industry: one group (69 subjects) exposed to hand-arm vibration in several workplaces, one group (62) performing heavy and repetitive hand and arm work but without exposure to vibration, and one control group (46) performing light and non-repetitive tasks without vibration. All the workers were interviewed by questionnaire, about their personal characteristics, their health status, their actual and past working conditions and the episodes of tingling at the level of the fingers. From these reported symptoms, the sensorineural stage of the hand-arm vibration was determined using the Stockholm scale. Based on the review of the literature, we selected six functional and sensory tests: maximum voluntary grip force, maximum angles of the wrist, pressure perception threshold test, vibration perception threshold test, distal sensory latency and the Purdue Pegboard test. Each test was performed by the workers in the three groups.

RESULTS

No main differences were observed between the personal characteristics of the three groups. According to the Stockholm scale, the sensorineural symptoms were mainly at stage SN1, with 9% at stage SN2 and none at stage SN3. These symptoms are associated with exposure to vibration, and had a prevalence of 40% in group 1, versus 20% in the two other groups. Furthermore, 25% of the workers exposed to vibration complained of symptoms at least once a week, compared with only 2% in the other groups. The multivariate logistic regression analysis showed an association between the existence of symptoms and a decrease in the maximum flexion angle of the wrist and an increase in the pressure perception threshold. This association, however, was too low to determine limit values with a sensitivity and specificity sufficiently high to make a reliable diagnosis.

CONCLUSIONS

The sensorineural symptoms at stage N1 on the Stockholm scale, experienced occasionally by some 40% of the users of vibrating tools, could not be corroborated by the functional and sensory tests.

Injuries to the lateral femoral cutaneous nerve during spine surgery

STUDY DESIGN

A prospective study to locate patients with injured lateral femoral cutaneous nerve after elective spine surgery.

OBJECTIVES

To assess the prevalence of injury of the lateral femoral cutaneous nerve and to identify the cause of injury according to the position of the patients at surgery and the surgical approach.

SUMMARY OF BACKGROUND DATA

Injuries to the lateral femoral cutaneous nerve, also known as meralgia paresthetica, may cause pain and therefore result in restriction of activity. Compression of the nerve by disc hernia, retroperitoneal tumors, and external pressure around the anterior superior iliac spine are among the more common causes.

METHODS

One hundred five patients admitted for elective spine procedures were grouped according to position on the operating table and surgical approach. All patients were examined before and after surgery for signs of injury to the lateral femoral cutaneous nerve, and those found injured were followed up for 1 year after surgery.

RESULTS

Injury to the lateral femoral cutaneous nerve was found in 21 (20%) patients. In 6 of them, all of whom underwent surgery on the Hall-Relton frame, the injury was bilateral. In 7 patients the injury was not associated with discomfort. In addition to injury by external pressure at the anterior superior iliac spine from the Hall-Relton frame, the nerve was also injured at the retroperitoneum by hematoma or traction and at the anterior iliac crest when bone was harvested. In 89% of the patients, the nerve completely recovered within 3 months of surgery. Two patients still had pain 1 year after surgery and hypoesthesia of the anterolateral thigh.

CONCLUSION

Injuries to the lateral femoral cutaneous nerve during spine surgery are frequent, and patients should be informed of the possible risk. It usually has a benign course, but some preventive steps should be taken: keep posterior to the anterior superior iliac spine and minimize retraction when harvesting a bone graft, pad the posts of the Hall-Relton frame over the anterior superior iliac crest, and avoid traction on the psoas muscle during the retroperitoneal dissection.

[How to avoid injuries in connection with surgery? Perioperative nerve injuries are probably underreported]

The occurrence of mechanical nerve injury in connection with anaesthesia and surgery is probably more common than generally believed, and by no means all cases are reported to the patient injury claims department. Both incorrect positioning of the patient on the operating table and pressure from retractors and other instruments can contribute to the occurrence of such injuries. Both neurological and neurophysiological procedures should be used to localise the injury, particularly for the purpose of insurance assessment. Most important of all, however, is prevention of injury. Risk minimisation is dependent on the observation of meticulous routines in surgery units, and clear division of staff responsibilities. The surgical injury rate can be monitored by means of a register of general complications.

Multiple nerve entrapment syndromes in office workers

Reports of nerve compression syndromes have been increasing in frequency. The authors discuss evaluation, management, and surgical repair of these multifactorial disorders.

Combined hyperactive dysfunction syndrome of the cranial nerves: trigeminal neuralgia, hemifacial spasm, and glossopharyngeal neuralgia: 11-year experience and review

OBJECTIVE

A pathological condition caused by vascular compression at the root entry/exit zone of the cranial nerves is designated hyperactive dysfunction syndrome (HDS) of the cranial nerves. Patients with HDS who exhibited a combination of trigeminal neuralgia (TN), hemifacial spasm (HFS), and/or glossopharyngeal neuralgia were retrospectively reviewed, to study the incidence, etiological factors, and demographic characteristics for this combined HDS group.

METHODS

Medical and surgical records were analyzed for 41 patients with combined HDS, of 1472 consecutive patients with HDS who were treated between 1984 and 1994.

RESULTS

The combined HDS group accounted for 2.8% of all patients with HDS; 19 patients (1.3%) exhibited bilateral symptoms, i.e., 14 cases of TN, 3 of combined TN and HFS, and 2 of HFS. Twenty-two patients (1.5%) exhibited ipsilateral symptoms, i.e., 19 cases of TN and HFS and 3 of TN and glossopharyngeal neuralgia. Excluding three patients whose symptoms were associated with brain tumors or arteriovenous malformations, this patient group was older (63.2 versus 55.3 yr, P = 0.0009) and exhibited an increased percentage of associated hypertension (47.4 versus 17.5%, P = 0.000008), with a female predominance (86.8 versus 71.3%, P = 0.07), compared with the single HDS group. Thirty-six of these patients underwent a total of 61 microvascular decompression procedures, with favorable outcomes. The offending vessels were similar to those in single HDS, which were usually conventional and multiple.

CONCLUSION

The associated etiological factors for vascular compression syndromes were more evident in the combined HDS group than in the single HDS group. Progressive arteriosclerotic vasculoarchitectural changes of the vertebrobasilar system, accelerated by aging and hypertension, bring about the development of combined HDS, with a remarkable female predominance.

MR imaging of the lumbar spine: prevalence of intervertebral disk extrusion and sequestration, nerve root compression, end plate abnormalities, and osteoarthritis of the facet joints in asymptomatic volunteers

PURPOSE

To identify the magnetic resonance (MR) abnormalities of the lumbar spine that have a low prevalence in asymptomatic patients and thus determine the findings that are predictive of low back pain in symptomatic patients.

MATERIALS AND METHODS

Sagittal T1-weighted and sagittal and axial T2-weighted MR images were obtained in 60 asymptomatic volunteers aged 20-50 years. The MR images were evaluated with regard to intervertebral disk abnormalities, end plate abnormalities, and osteoarthritis of the facet joints by two musculoskeletal radiologists independently.

RESULTS

Disk bulging or disk protrusion was found in 42 (14%) and 48 (16%) of the intervertebral spaces in 37 (62%) and 40 (67%) subjects, respectively. High-signal-intensity zones were found commonly (in 23 [7.7%] and 25 [8.3%] of the intervertebral spaces in 19 (32%) and 20 (33%) subjects, respectively). Disk extrusions were less common (in 11 [3.7%] and 11 [3.7%] of the intervertebral spaces in 11 (18%) and 11 (18%) subjects, respectively). There were no disk sequestrations. A nerve root compression in a single intervertebral space was diagnosed by one reader. End plate abnormalities were found in two (0.7%) and six (1.9%) of the intervertebral spaces in two (3%) and six (10%) subjects, respectively. No severe osteoarthritis was diagnosed by either reader.

CONCLUSION

In patients younger than 50 years, disk extrusion and sequestration, nerve root compression, end plate abnormalities, and osteoarthritis of the facet joints are rare and, therefore, may be predictive of low back pain in symptomatic patients.

Pain drawings in the assessment of nerve root compression: a comparative study with lumbar spine magnetic resonance imaging

STUDY DESIGN

Prospective comparative study of pain drawings with findings on lumbar spine magnetic resonance imaging.

OBJECTIVES

To assess the ability of the pain drawing to predict the presence of nerve root compression.

SUMMARY OF BACKGROUND DATA

Most research work has concentrated on the ability of the pain drawing to act as a screening method for psychological distress with less work directed at the influence the anatomic abnormality has on the pain drawing.

METHODS

One hundred thirty-four consecutive outpatients attending for lumbar magnetic resonance imaging in the investigation of back and leg pain completed pain drawings and psychological testing immediately before the examination. The pain drawing was analyzed by previously reported criteria, and the magnetic resonance imaging was assessed independently for the presence of nerve compression by three radiologists. Multivariate stepwise discriminant analysis was used to identify patients with nerve compression on the basis of their pain drawing.

RESULTS

Nerve compression was predicted by numbness in the anterolateral aspect of the foot. There was considerable overlap in the appearances of the pain drawings between patients with and without nerve compression, and the pain drawing correctly classified only 58% of patients with nerve compression.

CONCLUSIONS

The pain drawing is not a good predictor of nerve compression on magnetic resonance imaging in a group of patients investigated for back and leg pain. It should be interpreted with caution and in light of the full clinical picture.

Mononeuropathies associated with liver transplantation

Mononeuropathies associated with orthotopic liver transplantation were evaluated in a prospective manner. Ten percent of liver transplant recipients were noted to have focal peripheral nerve lesions in the postoperative period. The ulnar nerve was most commonly involved, with intraoperative compression or postoperative trauma as possible mechanisms of injury. Other upper extremity mononeuropathies were likely a result of vascular cannulations. No brachial plexus injuries occurred. Diabetes and alcoholism were not risk factors for the development of a mononeuropathy.

Nerve injury in repetitive motion disorders

Nerve compression in repetitive motion disorders is being recognized with increasing frequency. The pathophysiology of chronic nerve compression spans a broad spectrum beginning with subperineurial edema and progressing to axonal degeneration. These changes depend on the amount and duration of the compressive forces. Certain postures or positions in the upper extremity will increase pressures around certain nerves increasing pressure exposure. Evaluation of these patients with chronic nerve compression should include examination at all levels of potential entrapment in the upper extremity to identify all sites of compression.

Upper extremity nerve involvement in Swedish female machine milkers

Entrapment of the median nerve in the proximal forearm, the so-called pronator syndrome, is considered a rather rare condition but it is four times more common in women than in men. In this study, 23 of 30 female machine milkers with symptoms in the forearm and hand were clinically diagnosed as having the pronator syndrome. The diagnosis of median nerve involvement was based on the clinical history and on physical examination by a hand surgeon. All 23 milkers complained of aching in the volar part of the forearm and had a sensation of numbness, tingling, and decreased muscle strength in their hands, mostly in the hands which usually were statically loaded with heavy equipment. Objectively, all had an experience of tenderness over the pronator teres muscle. Furthermore, they showed reduced muscle strength, especially in the following muscles: pronator teres (PT), flexor carpi radialis (FCR), flexor pollicis longus (FPL), and flexor digitorum profundus II (FDP II). To validate the manual muscle testing, Mannerfeldt's intrinsicmeter was used to quantify the clinically observed weakness. Eight of the 23 milkers with pronator syndrome were surgically released from neuropathy and were almost symptom-free at follow-up after six months. One patient had a slight sensation of numbness and had to be given surgical carpal tunnel release later on. The external exposure of the arm during the application of the milking cluster probably causes muscle and fascial tensions that induce compression of the nerve. Further studies are needed to establish the level of the internal exposure.

[Injury risk of competitive, handicapped cross-country skiers in training nd competition]

Injuries caused by cross country skiing have been poorly investigated in handicapped athletes. The dynamic sliding shape of motion makes this sport to a suitable discipline for people with a deficit of locomotion. Visual handicapped people with a guide are able to improve their motoric skills, co-ordination, orientation and body self-consciousness in the track. Since handicapped athletes are performing in international competitions the training intensity to fulfill the requirements, but also the risk of overstrain induced injuries got increased, like in other high-performance sports. Our study examined injuries and overuse syndromes of the German National Team Ski Nordic during the Paralympics in Tignes/ Albertville (1992). Lillehammer (1994) and the training period in preparation for the Paralympics in Nagano (March 1998). The incidence and kind of injuries in the competitive handicapped cross country skier was comparable with non-handicapped athletes, but the injury pattern was different.

Compression of the peroneal nerve by a cyst in a seven-year-old child

Compressions of the peroneal nerve are rare since only some sixty such cases have been described since 1921. The authors report a new observation of compression extrinsic to the peroneal nerve by a synovial cyst, the source of which was the upper fibulo-tibial joint, in a child of seven years. As far as we know, this is the youngest age found in the relevant literature. Because of a swiftly appearing painful swelling, along with complete paralysis of the peroneal nerve, an electromyogram and a nuclear magnetic resonance were performed, with a view to confirming the diagnosis and to clarifying the topography of the cyst. The removal of the latter led to the child being cured with complete recovery of the peroneal nerve within three months.

Pain responses in patients with upper-extremity disorders

The purpose of this study was to evaluate the relationship between pain response factors and upper-extremity disorders associated with work-related compensable disorders. In this retrospective study, the charts of 113 patients were examined. Compensation was not found to have any statistically significant association with pain levels. The degree of functional overlay in these patients, indicated by pain questionnaire scores, differed only slightly between compensated and noncompensated patients and indicated no significant difference between the 2 groups, except that the compensated group used a higher number of descriptors to describe their pain (p = .0143). These results indicate that compensation affects the verbalization of pain but does not affect the degree of pain experienced. Working status was found to be significantly correlated with a better ability to cope with stress at home, suggesting that employment status may be a more important factor than compensation status in the presentation of these patients.

Lower urinary tract symptoms in lumbar root compression syndromes: a prospective survey

STUDY DESIGN

A prospective, observational survey.

OBJECTIVES

To describe lower urinary tract symptoms in uncomplicated lumbar root compression syndromes with special reference to prevalence, nature, and severity, and to analyze whether the occurrence of lower urinary tract symptoms correlates with age, pain, analgesic intake, or the type and level of compression.

SUMMARY OF BACKGROUND DATA

Lower urinary tract symptoms with lumbar root compression are well known in the classic but rather rare cauda equina syndrome. However, micturition difficulties seem to be far more frequent in lumbar root compression syndromes.

METHODS

One hundred eight male patients admitted for surgery for lumbar disc herniation or spinal stenosis were investigated with an extensive questionnaire about their micturition.

RESULTS

Fifty-five percent had significant lower urinary tract symptoms. Eighty percent of the patients with spinal stenosis had symptoms. Thirty-three patients had irritative symptoms, 36 had obstructive symptoms, and 23 had retention symptoms. Twenty-four had severe symptoms. Median compression resulted in more symptoms than paramedian compression. There was no correlation between age, level of compression, drug intake, or pain score and lower urinary tract symptoms.

CONCLUSIONS

Lower urinary tract symptoms of mixed type occur with a high prevalence in male patients with lumbar root compression syndromes referred for neurosurgical evaluation and treatment.

Natural history of adolescent thoracolumbar and lumbar idiopathic scoliosis into adulthood

Thirty-four patients with adolescent idiopathic thoracolumbar, lumbar, or lumbar components of double major curves between 20 and 55 degrees were identified. This study group was compared with an age- and sex-matched control group with regard to back pain, radicular symptoms, and perception of handicap. The objectives of this study were to define the natural history of moderate-range adolescent idiopathic thoracolumbar, lumbar, and double major curves with a lumbar component in this range. Studies that exclusively examined the natural history of thoracolumbar and more caudad curves have not been undertaken. Data from other related studies is often clouded by various factors. We reviewed the charts and radiographs of 363 patients with idiopathic scoliosis seen between 1935 and 1975 with available original radiographs. Thirty-four of 65 patients (52%) answered a questionnaire pertaining to severity of pain, functional abilities, and perceived quality of life. The same questionnaire was answered by 31 age- and sex-matched controls for comparison. The average follow-up was 22 years, and average patient age at current follow-up was 36 years. Curves at skeletal maturity measured an average of 35 degrees. On a scale of 1-10 (severe), current low-back pain in the study group was rated a mean of 3.19 versus 1.94 in the control group. Twelve of 34 patients in the study group (35%) reported no back pain, versus 21 of 31 (68%) in the control group. Twenty-four percent of the study group had radicular symptoms compared with 16% of the control group. None of the 34 study patients and 1 control patient underwent surgery for back pain. With an average follow-up of 22 years, the study group reported handicap scores comparable to those of the control group. The average age of the study patients was only 36 years, but it is encouraging that these individuals have continued to do well for at least 20 years past skeletal maturity.

The low transverse Pfannenstiel incision and the prevalence of incisional hernia and nerve entrapment

OBJECTIVE

The authors determined the prevalence of incisional hernia and nerve entrapment in patients with a low transverse Pfannenstiel incision.

SUMMARY BACKGROUND DATA

The literature on the Pfannenstiel incision suggests an incisional hernia rate of 0.0% to 0.5%. However, in these series, physical examination, which is essential in the authors' view, was not performed. To the authors' knowledge, the prevalence of nerve entrapment after the Pfannenstiel incision is not known or has never been published.

METHODS

All adult women, operated on between 1986 and 1992 using a Pfannenstiel incision and not having had another lower abdominal incision other than for laparoscopy, were invited for follow-up at the outpatient department. All patients were interviewed and subjected to a physical examination, with special interest to the presence of incisional hernia or nerve entrapment.

RESULTS

In patients having had a Pfannenstiel incision, no incisional hernias were found. In patients also having had a laparoscopy, the incisional hernia rate was 3.5%. Nerve entrapment was found in 3.7%. The length of the incision was identified as a risk factor (p = 0.02).

CONCLUSIONS

Incisional hernia is a rare complication of the Pfannenstiel incision. Complications of nerve damage, however, are not uncommon and should be recognized. When possible, nerves should be identified and preserved, especially when extending the incision more laterally.