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Head and spine injuries in youth sports.

Careful study of the pathomechanics and epidemiology of sports-related spine injuries brings to light many common features. The incidence increases as the sport becomes increasingly violent and aggressive. Improperly conditioned neck muscles and lack of knowledge of the proper techniques of the sport put the athlete who sustains a blow to the head at significant risk for head and/or spine injury. Improper helmet fit and the use of the head as an offensive weapon are also common features. Although recognition of these features has resulted in a dramatic reduction in catastrophic athletic spine injury, the athlete remains at risk for less severe head and spine injury.

Athletic Injuries↗

Head and neck soft tissue sarcomas of adult: prognostic value of surgery in multimodal therapeutic approach.

Adult head and neck soft tissue sarcomas (AHNSTS) are rare, and data concerning treatment results are spare. To assess clinico-pathological characteristics, management prognostic factors, and survival of AHNSTS, we reviewed our experience of 28 recent successive new cases. Data were collected from a retrospective database (1997-2002). Aggressive fibromatosis, dermatofibrosarcoma, Kaposi sarcoma, chondrosarcoma and osteogenic sarcoma were excluded. Univariate analysis for prognostic factors was performed with chi2 test with Yates correction. The median age was 45.7 years (range: 18-86). The male/female ratio was 15/13. The most common subtypes was rhabdomyosarcoma (seven cases). Twenty-two patients presented with previous inadequate resection performed elsewhere before admission. The most common location was neck muscles (11 cases). Nineteen patients had surgery (complete resection in 13 cases). Associated treatments were neoadjuvant chemotherapy, adjuvant chemotherapy and postoperative radiotherapy in respectively, 4, 3 and 10 cases. The 2-year overall survival was 56%. Rhabdomyosarcomas (p = 0.005) and inadequate resection (p = 0.04) were associated with poor outcome. Large resection of AHNSTS in a multimodality approach may afford the best chance of disease control.

Adolescent↗

Measuring the progression of foreign-body reaction to silicone implants using in vivo MR microscopy.

We used in vivo magnetic resonance (MR) microscopy to follow the growth of fibrous capsule as a foreign body reaction to silicone implants in rats. Anesthetized rats were imaged 1, 7, 14, and 28 days after silicone-coated MR imaging coils were sutured to their neck muscles. On the twenty-eighth day, rats were sacrificed and coils and adjacent tissues were removed en bloc and fixed in formalin, reimaged with MR, and sectioned for conventional histology. Three-dimensional (3-D) spin-echo [3DFT] acquisition gave in-plane resolution of 32 x 32 microns in vivo and 16 x 16 microns ex vivo. All MR images showed a diffuse band of elevated signal intensity between the silicone of the coil and adjacent tissue. The border of the hyperintense band was thin and not well defined at seven days post-implantation. From 7-28 days, the band showed relatively homogeneous signal intensity and its thickness increased 44% on the rectus muscle side and 78% on the subcutaneous side. The capsule thickness determined either by MR in vivo and ex vivo microscopy or conventional histology was not significantly different, and there was a significant correlation between thickness measurements among those methods. MR in vivo microscopy provides sufficient resolution and spatial information to serially evaluate the growth of the foreign body fibrous capsule over time, thus achieving greater accuracy and consistency in measurements.

Animals↗

Influence of vibration to the neck, trunk and lower extremity muscles on equilibrium in normal subjects and patients with unilateral labyrinthine dysfunction.

To investigate the role of proprioceptors of different skeletal muscles in postural control, in normal subjects and patients with unilateral labyrinthine dysfunction (ULD), the effect of vibration on these muscles was studied by postulography. The subjects comprised 59 normal subjects and 12 patients with ULD due to resection of acoustic tumours. Sagittal body sway was observed during vibration to the triceps surae, tibialis anterior and upper dorsal neck muscles. No significant change in sway was observed in the frontal plane in normal subjects. Significant differences between normal subjects and patients were found on stimulation of the muscle groups of triceps surae and biceps femoris during vibration. In patients with ULD, vibration to the dorsal neck muscles caused a deviation towards the diseased side. It can be speculated that the upper dorsal neck muscle plays an important role in maintaining the body balance in the frontal plane in patients with ULD. On the other hand, the lower extremity muscles, especially the muscles on the dorsal side of the body, play a significant role in adjusting the standing posture in the sagittal plane.

Adult↗

Simulation of bidirectional ultrasound hyperthermia treatments of neck tumours.

The temperature distributions produced in neck tumours by using either a single, scanned transducer (a unidirectional scan) or two separate transducers whose axis are perpendicular (a bidirectional scan) were simulated. The three-dimensional neck model included separate anatomical regions for the normal neck muscle tissue, the tumour, the spinal column and the trachea (no large blood vessels). The effects of variations in the transducer frequency and f number, the tumour size and location, and the normal and tumour blood perfusion rates were studies. The best simulated temperature distributions were produced by bidirectionally scanned, 2 MHz, f number 2.0 ultrasound transducers whose powers were modulated as a function of position. The simulated temperature distributions from such modulated bidirectional scans were significantly better than those of both unidirectional and unmodulated bidirectional scans. The 1-MHz transducers generally produced hot spots at the tissue-spine and/or tissue-trachea interface. The 3-MHz transducers eliminated those deep hot spots but created other hot spots close to the skin surface, and did not adequately heat the deeper regions of the tumour. These results from the simplified computer simulations may be used to guide the construction of improved ultrasound hyperthermia systems for the treatment of neck tumours.

Biophysical Phenomena↗

What is the optimal dose of botulinum toxin A in the treatment of cervical dystonia? Results of a double blind, placebo controlled, dose ranging study using Dysport. German Dystonia Study Group.

OBJECTIVES: Botulinum toxin injections have become a first line therapeutic approach in cervical dystonia. Nevertheless, published dosing schedules, responder rates, and frequency of adverse events vary widely. The present prospective multicentre placebo controlled double blind dose ranging study was performed in a homogenous group of previously untreated patients with rotational torticollis to obtain objective data on dose-response relations. METHODS: Seventy five patients were randomly assigned to receive treatment with placebo or total doses of 250, 500, and 1000 Dysport units divided between one splenius capitis (0, 175, 350, 700 units) and the contralateral sternocleidomastoid (0, 75, 150, 300 units) muscle. Assessments were obtained at baseline and weeks 2, 4, and 8 after treatment and comprised a modified Tsui scale, a four point pain scale, a checklist of adverse events, global assessment of improvement, and a global rating taking into account efficacy and adverse events. At week 8 the need for retreatment was assessed and then the code was unblinded. For those still responding, there was an open follow up until retreatment to assess the duration of effect. RESULTS: Seventy nine per cent reported subjective improvement at one or more follow up visits. Decreases in the modified Tsui score were significant at week 4 for the 500 and 1000 unit groups versus placebo (p<0.05). Additionally positive dose-response relations were found for the degree of subjective improvement, duration of improvement, improvement on clinical global rating, and need for reinjection at eight weeks. A significant dose relation was also established for the number of adverse events overall and for the incidence of neck muscle weakness and voice changes. CONCLUSION: Magnitude and duration of improvement was greatest after injections of 1000 units Dysport; however, at the cost of significantly more adverse events. Therefore a lower starting dose of 500 units Dysport is recommended in patients with cervical dystonia, with upward titration at subsequent injection sessions if clinically necessary.

Adult↗

Bony mass associated with hypertrophy of the sternohyoid muscle after radical neck dissection.

As a late complication after radical neck dissection, this paper reports a bony mass at the sternal end of the clavicle associated with hypertrophy of the sternohyoid muscle. The bony mass and hypertrophy of the muscle were considered due to continuous mechanical strain by the drooping of the shoulder caused by injury of the accessory and cervical nerves, left-handed physical labour, and the lack of the sternocleidomastoid muscle in rotating the head.

Adult↗

Variations in diurnal and nocturnal waking state in air traffic controllers.

Physiological variables of 22 air traffic controllers (ATCs), mean age 32, were continuously telemetrically recorded from 08:00 to 17:30 and on the following day from 19:00 to either 00:00 or 0.3:00. EEG (alpha and theta indices, slow delta waves), EOG (palpebral blinks), EMG (from the neck muscles) and EKG (HR) were recorded. Comparison between day and night shows an increase at night of HR and slow waves, particularly after midnight. These results were compared with similar ones obtained from two other populations of the same age having very different professional activities (university personnel and factory workers). The EEG indices and HR are higher in ATCs. The work load imposed by the need in air traffic control to maintain a high level of vigilance, especially difficult after midnight, is in great part responsible for the high values of physiological parameters observed in this study.

Adult↗

The effect of experimental muscle pain on the amplitude and velocity sensitivity of jaw closing muscle spindle afferents.

The effect of experimental muscle pain on the amplitude and velocity sensitivity of muscle spindle primary afferent neurons in the trigeminal mesencephalic nucleus (Vmes) was examined. Extracellular recordings were made from 45 neurons designated as spindle primary- or secondary-like on the basis of their response to ramp-and-hold jaw movements. Velocity sensitivity was assessed in spindle primary-like afferents by calculating the mean dynamic index of each unit in response to three different velocities of jaw opening before and after intramuscular injection with hypertonic saline (HS, 5%, 100 microl). The amplitude sensitivity of all jaw muscle spindle afferents was assessed by calculating the mean firing rate of each unit in response to three different amplitudes of jaw openings during both the open and hold phases of the movement and with best-fit lines obtained, using linear regression analysis, before and after HS injection. The variance of the two regression lines obtained for each unit before and after the injection was compared using the coincidence test, and changes in intercept and slope were determined. Seventy-five percent of the primary-like units and 80% of the secondary-like units presented with changes in static behavior after HS injection. Thirty-six percent of the primary-like units showed changes in dynamic behavior. Injection of isotonic saline (control) did not alter the responses of the spindle afferent to jaw opening. Thus, our results demonstrate that the predominant effect of noxious stimulation was a shift in the amplitude sensitivity of both spindle primary-like and secondary-like afferents and, to a lesser extent, the velocity sensitivity of the spindle primary-like unit. In accordance with earlier studies in the cat hindlimb and neck muscles, these results suggest that the activation of masseter muscle nociceptor alters spindle afferent responses to stretch acting primarily through static gamma motor neurons.

Animals↗

Effects of static tilt on cervical spinoreticular tract neurons.

The activity of axons located mainly in the ventral part of the lateral funiculi of the cervical segments C2-C3 were recorded in precollicular decerebrate cats and their responses to lateral tilt of the whole animal studied. Units were identified according to their antidromic and/or transynaptic responses to stimulation of the ipsilateral lateral reticular nucleus (NRL) as well as their responses to ipsilateral and/or contralateral forelimb nerve stimulation. In most respects, those units which could be antidromically identified as cervical ascending tract axons showed properties similar to those described for neurons of the spinoreticular pathway, the bVFRT. Among the 106 recorded units, 42 responded to 15 degrees tilts in the median plane. Steady changes in unit discharge frequency were evoked by tilting, which lasted as long as the position of the cat was maintained. The response of the units to tilting consisted of increased in discharge rate during tilt in one direction, while tilt in the opposite direction resulted in a decrease in discharge rate. The magnitude of the responses was clearly related to the degree of tilt. All the units affected by tilt, except one, received inputs from both ipsilateral and contralateral forelimb nerves and some of them also from high-threshold neck muscle afferents. Furthermore, 12 of these units could be orthodromically excited at short latency from the ipsilateral brain stem, suggesting a possible monosynaptic input perhaps transmitted via the lateral vestibulospinal tract. The responses of the cervical ascending spinal tract units to tilt did not appear to depend on peripheral proprioceptive or cutaneous feedback since a number of precautions were taken to eliminate such influences, while control experiments in animals submitted to partial or complete bilateral VIIth nerve section showed the number of neurons responsive to tilt to be profoundly reduced or eliminated. It appeared also that the average spontaneous discharge rate of the ascending units was much lower following bilateral VIIth nerve section than that obtained from the corresponding units recorded in preparations with the VIIth nerves intact. These findings suggested that the responses of the cervical ascending neurons to tilt as well as their spontaneous background activity depended on influences arising from the macular labyrinthine receptors. The observation that the responses of these ascending neurons to peripheral nerve stimulation are modified by tilt further suggested that the macular system may interact with the somatosensory system originating from the forelimb and the neck musculature, thus being able to produce the fine adjustments that cerebellar and brain stem structures exert in the control of posture and movements.

Animals↗

Convergence of sensory inputs upon projection neurons of somatosensory cortex: vestibular, neck, head, and forelimb inputs.

Cortico-cortical neurons and pyramidal tract (PT) neurons of the cat cerebral cortex were tested for convergent inputs from electrically stimulated vestibular, neck, head and forelimb nerves. Neurons were recorded within forelimb and vestibular projection regions of cortical area 3a. Consideration was given to both suprathreshold and subthreshold inputs. Neither vestibular, neck nor head inputs were detected in the forelimb region of area 3a. In contrast, within the vestibular projection region of area 3a, 43% (6/14) of the cortico-cortical neurons and 63% (24/38) of the PT neurons received excitatory vestibular input. Inputs from the skin of the pinna (greater auricular nerve) were detected only for PT neurons (66%, 25/38). No inputs were detected from afferent nerves supplying the dorsal neck muscles biventer cervicis and complexus. Cortico-cortical and PT neurons receiving vestibular input also received convergent inputs originating from forelimb group I deep and low threshold cutaneous afferent fibers. Further, one half of the PT neurons with vestibular input (12/24) received input from three somatic sources: forelimb group I deep, forelimb low threshold cutaneous and greater auricular (head) nerves. The input connectivities suggest a role for these projection neurons of somatosensory cortex in the coordination of head and forelimb movements. The convergence of vestibular information with somatic input from the forelimb implies that vestibular-influenced neurons of area 3a projecting to the motor cortex or through the pyramidal tract would signal head position or movement with respect to proprioceptive feedback from the limbs.

Afferent Pathways↗

Noninvasive treatments for headache.

Primary headache disorders are often accompanied by neck pain or other symptoms referable to neck muscles. Therefore, physical therapy and other physical treatments are commonly prescribed for headache management. A medical literature review was completed in order to gather information regarding the efficacy of selected physical modalities in the treatment of primary and cervicogenic headache disorders. After analyzing the collected data, expert opinions were developed regarding the utility and efficacy of selected physical modalities in the management of primary and cervicogenic headaches. Based on this review, the following four expert opinions are presented: physical therapy is more effective than massage therapy or acupuncture for the treatment of tension-type headache and appears to be most beneficial for patients with a high frequency of headache attacks. Physical therapy is most effective for the treatment of migraine when combined with other treatments such as thermal biofeedback, relaxation training and exercise. Chiropractic manipulation demonstrated a trend towards benefit in the treatment of tension-type headache, but evidence is weak. Chiropractic manipulation is probably more effective in the treatment of tension-type headache than it is in the treatment of migraine. In general, strong evidence is lacking regarding the efficacy of these treatments in reducing headache frequency, intensity, duration and disability in many commonly encountered clinical situations. Many of the published case series and controlled studies are of low quality. Physical treatments are unlikely to pose a significant risk, with the exception of high velocity chiropractic manipulation of the neck. Consideration must be given to financial costs and lost treatment opportunity by prescribing potentially ineffective treatment. In the absence of clear evidence regarding their role in treatment, physicians and patients are advised to make cautious and individualized judgments about the utility of physical treatments for headache management. In most cases, the use of physical modalities should complement rather than replace better validated forms of therapy. The evidence base to determine the safety and efficacy of physical treatments in the management of headache disorders would be substantially improved by using standard scientific rigor in the development and conduct of future clinical studies.

Biofeedback, Psychology↗

The use of an open-freezing system with self-seeding for cryopreservation of mouse ovarian tissue.

Chemoradiotherapy in young women with cancer has substantially improved life expectancy in these patients, but these treatments often cause infertility. One method of preserving fertility is to cryopreserve ovarian tissue. In this study, an automatic open-vessel freezing system with self-seeding was tested for cryopreservation of murine ovarian tissue; the mouse is a species widely used in human and veterinary medical research. The freezing system concerned, is used for cryopreservation of oocytes and embryos in Europe. Twenty severe combined immunodeficiency (SCID) mice were ovariectomized. The ovarian tissue was either directly transplanted heterotopically into the neck muscle (group 1, n = 6) or cryopreserved after equilibration with 1.5 M dimethylsulphoxide and propanediol. After thawing, the tissue was transplanted in SCID mice (group 2, n = 6). Before and after thawing, a part of the ovarian tissue was examined with the LIVE/DEAD fluorescent viability staining. The count of follicles revealed intact (fresh 24.1%/thawed 21.7%), impaired (fresh 35.1%/thawed 35.4%), and dead follicles (fresh 40.8%/thawed 42.9%). The healthy follicular loss because of the cryopreservation was 10.0%. All recipient mice were killed after 3 weeks. Transplanted ovarian tissue was found macroscopically in all mice. Histological examination showed several growing follicles in all developmental phases in both groups of SCID mice [group 1 (fresh grafts): 315 +/- 76.3 (mean +/- SD); group 2 (cryopreserved grafts): 237 +/- 63.4]. These results demonstrate that the use of an open-freezing system allows the survival of cryopreserved mouse ovarian tissue.

Animals↗

A preliminary comparison of the efficacy and tolerability of botulinum toxin serotypes A and B in the treatment of myofascial pain syndrome: a retrospective, open-label chart review.

BACKGROUND: Myofascial pain syndrome (MPS) is characterized by acute or chronic regional muscle pain associated with single or multiple trigger points within taut bands of muscle. Botulinum toxins have clinical utility when sustained focal muscle relaxation is required and may be a useful addition to the treatment armamentarium for MPS. OBJECTIVE: The purpose of the present article was to compare the efficacy and tolerability of botulinum toxin serotypes A and B (BTX-A and BTX-B) in the treatment of MPS. METHODS: This was a retrospective, open-label, single-center chart review. Charts of all patients who received either BTX-A or BTX-B for MPS between January and November 2001 were included in the review. Patients rated the intensity of their pain on a visual analog scale (VAS) from 0 = no pain to 10 = worst pain imaginable before and after receiving BTX-A or BTX-B. RESULTS: The charts of 91 patients (74.7% female, 25.3% male; mean [SD] age, 47 [10.2] years) who received BTX-A (n = 56; mean dose, 256.9 U; range, 100-600 U) or BTX-B (n = 35; mean dose, 9000 U; range, 2500-20,000 U) were included in this retrospective review. Patients who received BTX-A had significantly greater mean reductions in VAS pain scores compared with those who received BTX-B (mean reduction, 2.7 vs 1.8, respectively; P < 0.001). Patients who received BTX-A also reported significantly longer durations of pain relief compared with those who received BTX-B (4.5 vs 2.7) months; P < 0.001). Eight of 56 patients (14.3%) in the group that received BTX-A reported mild adverse events that included flulike symptoms, injection-site pain, and weakness of the neck muscles. Seven of 35 patients (20.0%) in the group that received BTX-B reported adverse events that included mild flulike symptoms, dry eyes, severe visual disturbances, and severe dry mouth. CONCLUSION: Patients with MPS who received BTX-A reported significantly greater reductions in pain for longer durations compared with those who received BTX-B. No patients who received BTX-A experienced severe systemic adverse events, compared with 4 patients who received BTX-B. The results of this comparison are consistent with the US Food and Drug Administration-approved labeling indicating that BTX-A is not interchangeable with any other botulinum toxin in terms of biological activity.

Botulinum Toxins↗

Pattern of LH and testosterone secretion of adult male fallow deer (Dama dama) during the transition into the breeding season.

Pituitary secretion of LH and testicular secretion of testosterone were investigated during the transitional period from the non-breeding to breeding season of mature male fallow deer exhibiting either normal transitional patterns or shortened transitional patterns in response to summer melatonin treatment. Melatonin implants were administered to 4 bucks for a 150-day period starting 130 days after the winter solstice. Four contemporary bucks served as controls. Melatonin treatment advanced rutting activity, testis development and neck muscle hypertrophy by 6-8 weeks. Profiles of plasma LH and testosterone, based on a 30-min sampling frequency over 24 h, were obtained from 3 treated and 3 control bucks on 4 occasions over the period spanning the transition into the breeding season. In control bucks, LH and testosterone pulse frequency were low (0-2 pulses/24 h) in January and increased (5-7 pulses/24 h) in February. By March and April (pre-rut and rut periods respectively) there was a two-fold increase in basal plasma LH concentrations, a decline in LH pulse frequency (0-1 pulse/24 h) and episodic surges in plasma testosterone concentrations. Melatonin treatment resulted in a shift in hormone profiles, with highly pulsatile patterns of LH and testosterone secretion (7 pulses/24 h) occurring earlier in January. The subsequent post-rut profiles of treated bucks were characterized by lower basal plasma LH concentrations, and reduced frequency and amplitude of plasma testosterone surges.

Animals↗

Positive pressure on neck reduces baroreflex response to apnoea.

This study was designed to evaluate the arterial blood pressure and heart rate responses to positive pressure applied to the neck during repetitive inspiratory apnoea. Twenty-five subjects (aged 20-40 years) were trained to exert a positive pressure on the neck by actively contracting the neck muscles and pressing the chin in the jugular notch. Blood pressure and heart rate were evaluated during 5-min long periods at rest, at the beginning and end of a 25-min period of apnoea with and without positive pressure and after a second period of rest. Positive pressure diminished the initial hypotensive and bradycardiac reactions to apnoea and augmented the heart rate and blood pressure increase towards the end of apnoea. Both systolic and diastolic pressures and heart rate were significantly elevated during both apnoeic sequences, and also remained significantly elevated after the release of pressure. Spectral analysis (FFT) and auto-regressive model showed the entrainment of the slow 0.03 Hz oscillations by repetitive apnoea and the occurrence of 0.1 Hz and respiratory 0.2 Hz components in the heart rate and blood pressure in both types of apnoea. It is suggested, since the positive pressure decreases the baroreflex and the increased sympathetic tone persists after apnoea, that such effects may contribute to the development of cardiac complications in prediposed individuals with obstructive apnoea syndrome.

Adult↗