Left Paraspinal Muscles Research Articles

Treatment of Abdominal Segmental Hernia, Constipation, and Pain Following Herpes Zoster with Paravertebral Block

Herpes zoster (HZ) most commonly occurs in elderly patients and involves sensory neurons resulting in pain and sensory changes. Clinically significant motor deficits and visceral neuropathies are thought to be relatively rare. A 72-year-old man presented with abdominal segmental hernia, constipation, and pain following HZ in the left T9-10 dermatome. Sixteen days before presentation, he had developed a painful herpetic rash in the left upper abdominal quadrant. Approximately 10 days after the onset of the rash, constipation occurred and was managed with daily oral medication with bisacodyl 5 mg. In addition, 14 days after the onset of HZ, the patient noticed a protrusion of the left upper abdominal wall. Abdominal x-ray, ultrasound of the abdomen, and electrolyte analysis showed no abnormalities. General physical examination revealed a reducible bulge in his left upper quadrant and superficial abdominal reflexes were diminished in the affected region. Electromyographic testing revealed denervational changes limited to the left thoracic paraspinal muscles and supraumbilical muscles, corresponding to the affected dermatomes. He was prescribed with 500 mg of famciclovir 3 times a day for 7 days, and pregabalin 75 mg twice a day and acetaminophen 650 mg 3 times a day for 14 days. However, his pain was rated at an intensity of 5 on the numerical analogue scale from 0 (no pain) to 10 (worst pain imaginable). A paravertebral block was performed at T9-10 with a mixture of 0.5% lidocaine 3 mL and triamcinolone 40 mg. One day after the procedure, the abdominal pain disappeared. In addition, 5 days after the intervention, the abdominal protrusion and constipation were resolved. He currently remains symptom free at a 6 month follow-up. Key words: Abdominal, constipation, electromyography, herpes zoster, hernia, motor, paravertebral block, pain, steroid, dermatome

Biomechanical analysis of knee and trunk in badminton players with and without knee pain during backhand diagonal lunges

The contribution of core neuromuscular control to the dynamic stability of badminton players with and without knee pain during backhand lunges has not been investigated. Accordingly, this study compared the kinematics of the lower extremity, the trunk movement, the muscle activation and the balance performance of knee-injured and knee-uninjured badminton players when performing backhand stroke diagonal lunges. Seventeen participants with chronic knee pain (injured group) and 17 healthy participants (control group) randomly performed two diagonal backhand lunges in the forward and backward directions, respectively. This study showed that the injured group had lower frontal and horizontal motions of the knee joint, a smaller hip–shoulder separation angle and a reduced trunk tilt angle. In addition, the injured group exhibited a greater left paraspinal muscle activity, while the control group demonstrated a greater activation of the vastus lateralis, vastus medialis and medial gastrocnemius muscle groups. Finally, the injured group showed a smaller distance between centre of mass (COM) and centre of pressure, and a lower peak COM velocity when performing the backhand backward lunge tasks. In conclusion, the injured group used reduced knee and trunk motions to complete the backhand lunge tasks. Furthermore, the paraspinal muscles contributed to the lunge performance of the individuals with knee pain, whereas the knee extensors and ankle plantar flexor played a greater role for those without knee pain.

Effects of support surface stability on feedback control of trunk posture.

This study aimed to examine the interactions of visual, vestibular, proprioceptive, and tactile sensory manipulations and sitting on either a stable or an unstable surface on mediolateral (ML) trunk sway. Fifteen individuals were measured. In each trial, subjects sat as quiet as possible, on a stable or unstable surface, with or without each of four sensory manipulations: visual (eyes open/closed), vestibular (left and right galvanic vestibular stimulation alternating at 0.25 Hz), proprioceptive (left and right paraspinal muscle vibration alternating at 0.25 Hz), and tactile (minimal finger contact with object moving in the frontal plane at 0.25 Hz). The root mean square (RMS) and the power at 0.25 Hz (P25) of the ML trunk acceleration were the dependent variables. The latter was analyzed only for the rhythmic sensory manipulations and the reference condition. RMS was always significantly larger on the unstable than the stable surface. Closing the eyes caused a significant increase in RMS, more so on the unstable surface. Vestibular stimulation significantly increased RMS and P25 and more so on the unstable surface. Main effects of the proprioceptive manipulation were significant, but the interactions with surface condition were not. Finally, also tactile manipulation increased RMS and P25, but did not interact with surface condition. Sensory information in feedback control of trunk posture appears to be reweighted depending on stability of the environment. The absolute effects of visual and vestibular manipulations increase on an unstable surface, suggesting a relative decrease in the weights of proprioceptive and tactile information.

La trasformazione di una sindrome lombovertebrale in stato confusionale acuto

Here we report the case of a 19-year-old somalian man who has been admitted to our emergency department because of an important lumbago without trauma. The physical examination on arrival showed a diffuse painful percussion of the left paraspinal muscles without neurological impairment. The laboratory exams displayed a significant elevation of the inflammatory response (CRP 154 mg/l, procalcitonin 0,05 µg/l), the blood cultures were negative and a thoracic and lumbar computed tomography (CT) was not conclusive. The unclear clinical picture led to a magnetic resonance imaging, showing the presence of an abscess in the left thoraco-lumbar paraspinal musculature with ongoing invasion of the epidural space. The clinical picture became dramatic as the patient suddenly developed a frank nuchal rigidity associated with an acute confusional state, caused by the rupture of the abscess in the meningeal space with secondary meningitis, confirmed by a lumbar puncture, where S. aureus was found.

Agreement and Reproducibility of Apparent Diffusion Coefficient Measurements of Dual-b-Value and Multi-b-Value Diffusion-Weighted Magnetic Resonance Imaging at 1.5 Tesla in Phantom and in Soft Tissues of the Abdomen

To compare the coefficient of variation (CV) and long-term reproducibility of apparent diffusion coefficient (ADC) in a simple fluid-filled phantom and abdominal organs simultaneously. Retrospective institutional review board-approved and Health Insurance Portability and Accountability Act-compliant study sequentially selected 100 patients who underwent clinically indicated abdominal magnetic resonance imaging. A subset of 58 patients had repeat scans within 2 to 5 months after the initial magnetic resonance imaging. Two diffusion-weighted imaging techniques (b-values 0-750 mm/s) were performed to compare the ADC values. Mean ADC values were calculated for 10 locations and the reference phantom. The CV and Bland-Altman plots were calculated for the phantom and soft tissues at each session and location. There were no significant differences in the mean ADC values between repeated acquisitions. However, ADC values were statistically higher using dual-b-value than multi-b-value diffusion-weighted imaging. The CV for the phantom was 8.6 versus 10.8 for dual-b-value and multi-b-value, respectively. The CVs for the soft tissues had a wider range compared with that of the phantom (liver, 12.6 vs 9.0; spleen, 11.7 vs 11.2; gallbladder, 11.0 vs 13.6; head of pancreas, 14.6 vs 14.7; body of pancreas, 13.4 vs 13.0; tail of pancreas, 14.8 vs 16.3; right kidney, 9.1 vs 9.6; left kidney, 9.3 vs 9.3; right paraspinal muscle, 7.9 vs 7.5; left paraspinal muscle, 7.3 vs 7.3, respectively). A change in ADC less than 11% falls into the range of measurement variability. Paraspinal muscle could potentially be used as an internal reference parameter.

Ultrasound Guided Piriformis Injection with Confirmation of Needle Placement Through Electromyography

Dear Editor: Piriformis syndrome is a controversial topic that consists of a constellation of symptoms that may mimic spondylosis, radiculopathy, sacroiliac joint pain, and facet arthropathy [1]. One of the modalities of piriformis syndrome treatment is direct injection of medication into the piriformis muscle belly [2]. Previous authors have reported various methods in performing piriformis injections: fluoroscopically, motor stimulation, and most recently, ultrasound (US) guidance [3–5]. We describe a case presentation and, to our knowledge, the first report of combined use of US with electromyography (EMG) confirmation of muscle placement for piriformis muscle injection. A 60-year-old male presented to our clinic with lower back, left hip, and left buttock pain for 6 years. The pain was sharp in quality and radiated toward the left lateral buttock and hip. The pain was rated 6/10 at initial presentation and was aggravated by prolonged sitting, squatting, and bending over. Pain was improved with rest. On examination, the patient demonstrated mild tenderness along the left lumbar spine and paraspinal muscles, as well as tenderness to palpation in the left lateral buttock area. Straight leg raise test was positive in the left lower extremity. Motor examination revealed full …

Sternoclavicular joint septic arthritis following paraspinal muscle abscess and septic lumbar spondylodiscitis with epidural abscess in a patient with diabetes: a case report

BackgroundSeptic arthritis of the sternoclavicular joint (SCJ) is extremely rare, and usually appears to result from hematogenous spread. Predisposing factors include immunocompromising diseases such as diabetes.Case presentationA 61-year-old man with poorly controlled diabetes mellitus presented to our emergency department with low back pain, high fever, and a painful mass over his left SCJ. He had received two epidural blocks over the past 2 weeks for severe back and leg pain secondary to lumbar disc herniation. He did not complain of weakness or sensory changes of his lower limbs, and his bladder and bowel function were normal. He had no history of shoulder injection, subclavian vein catheterization, intravenous drug abuse, or focal infection including tooth decay. CT showed an abscess of the left SCJ, with extension into the mediastinum and sternocleidomastoid muscle, and left paraspinal muscle swelling at the level of L2. MRI showed spondylodiscitis of L3-L4 with a contiguous extradural abscess. Staphylococcus aureus was isolated from cultures of aspirated pus from his SCJ, and from his urine and blood. The SCJ abscess was incised and drained, and appropriate intravenous antibiotic therapy was administered. Two weeks after admission, the purulent discharge from the left SCJ had completely stopped, and the wound showed improvement. He was transferred to another ward for treatment of the ongoing back pain.ConclusionDiabetic patients with S. aureus bacteremia may be at risk of severe musculoskeletal infections via hematogenous spread.

The Osteoinductivity of Silicate-Substituted Calcium Phosphate

The osteoinductivity of silicate-substituted calcium phosphate and stoichiometric calcium phosphate was investigated with use of ectopic implantation. Implants with a macroporosity of 80% and a strut porosity of 30% were inserted into sites located in the left and right paraspinal muscles of six female sheep. After twelve weeks in vivo, a longitudinal thin section was prepared through the center of each implant. Bone formation within the implant, bone formation in contact with the implant surface, and implant resorption were quantified with use of a line intersection method. The specimens were also analyzed with use of backscattered scanning electron microscopy and energy-dispersive x-ray analysis. Silicate substitution had a significant effect on the formation of bone both within the implant and on the implant surface during the twelve-week period. Bone area within the implant was greater in the silicate-substituted calcium phosphate group (mean, 7.65% ± 3.2%) than in the stoichiometric calcium phosphate group (0.99% ± 0.9%, p = 0.01). The amount of bone formed at the surface of the implant was also significantly greater in the silicate-substituted calcium phosphate group (mean, 26.00% ± 7.8%) than in the stoichiometric calcium phosphate group (2.2% ± 2.0%, p = 0.01). Scanning electron microscopy demonstrated bone formation within pores that were <5 μm in size, and energy-dispersive x-ray analysis confirmed the presence of silicon within the new bone in the silicate-substituted calcium phosphate group. The formation of bone within muscle during the twelve-week period showed both silicate-substituted calcium phosphate and stoichiometric calcium phosphate to be osteoinductive in an ovine model. Silicate substitution significantly increased the amount of bone that formed and the amount of bone attached to the implant surface. New bone formation occurred through an intramembranous process within the implant structure.

Herpes zoster-induced abdominal wall paresis: Neurophysiological examination in this unusual complication

Background Herpes zoster affects essentially sensory fibres with segmental distribution. Abdominal wall paresis is a rare complication. Aims of the study We present the case of a 72 year-old man with herpes zoster infection in T11–T12 left dermatomes and segmental abdominal wall protrusion. Methods Electromyography (EMG) and dermatomal somatosensory evoked potentials (DSEPs) were performed 27 days after symptoms onset. Results EMG confirmed acute axonal lesion in left external oblique muscle and left paraspinal muscles at T11–T12 level and DSEPs assessed topographic distribution: there was no response in the left side at T12 dermatome. Three months following the onset of shingles, the abdominal wall protrusion had completely resolved. Conclusions Neurophysiological examination, including EMG and DSEPs, confirms motor and sensory loss in this unusual post-herpetic complication.

Paraspinal Muscle Function Assessed with the Flexion-Relaxation Ratio at Baseline in a Population of Patients with Back-Related Leg Pain

Objective The purpose of this study was to assess back muscle status at baseline in patients with back-related leg pain (BRLP) and to correlate those findings with baseline demographic and clinical factors. Methods Surface electromyography (EMG) and electromagnetic motion-tracking detected flexion-relaxation response in 135 patients with BRLP. Surface EMG electrodes were attached with standard skin preparation over the right and left paraspinal muscles at L3. Participants moved from upright standing into full forward flexion, rested flexed for 1 second, and returned to the upright position. A flexion-relaxation ratio (FRR) factor was calculated as the root mean square EMG amplitude during forward flexion divided by the activity at full flexion. Results High repeatability was found (intraclass correlation coefficient [ICC] [1,3] = 0.94 and 0.86) between 3 cycles of assessment at the same session. Patients with BRLP exhibited low FRR values, indicating a loss of the flexion-relaxation response similar to that seen in low back pain patients. Patients with very low FRR had higher Roland-Morris Disability Questionnaire scores than the other patients, had increased incidence of straight leg raise test, and had decreased range and rate of forward flexion. Conclusions A subgroup of patients with BRLP was identified with very low FRR who exhibited more disability and clinical findings and decreased motion. The use of the inverted FRR factor, expressing muscle activity at the fully flexed and resting position as a percentage of peak activity during flexion, provides more stable numerical behavior and another perspective on interpreting FRRs.

Experimentally induced low back pain from hypertonic saline injections into lumbar interspinous ligament and erector spinae muscle

Injection of hypertonic saline into back muscles or ligaments can induce acute low back pain (LBP). However, no study has systematically investigated pain characteristics from these structures. Further, induced muscle pain can change with stretching and contraction, which is problematic for studies into the effect of pain on sensorimotor control. However, it is unclear whether this occurs with experimental ligament pain. In separate sessions, 10 healthy volunteers received a single bolus injection of hypertonic (0.2 ml, 5% NaCl) or isotonic saline (0.3 ml, 0.9% NaCl) into L4/5 interspinous ligament, or hypertonic saline into the left paraspinal muscle. Pain intensity, size and duration were recorded, and a body chart was completed for each injection. Changes in pain intensity and size with stretching or back muscle contractions were also assessed during muscle and ligament pain. Injection of hypertonic saline into the interspinous ligament produced central LBP that was longer in duration and greater in intensity and size compared to hypertonic saline injection into lumbar paraspinal muscles. Isotonic saline injection into the interspinous ligament yielded mild pain that was short-lasting (<2 min). Intensity and size of muscle pain reduced with stretching and contraction, whereas these tasks did not affect ligament pain. Surprisingly, some participants pointed to a location of pain that was 1–2 segments above or below the injected level. The results highlight that injection into the interspinous ligament elicits consistent pain that is not influenced by trunk movements. These findings support the implementation of this experimental ligament pain model in research.

Immediate effects of a high-velocity spine manipulation in paraspinal muscles activity of nonspecific chronic low-back pain subjects

High-velocity spinal manipulation is commonly adopted for treating chronic low-back pain (CLBP) and has been associated with changes in muscle activity, but the evidence is controversial. The aim of this study was to analyse the immediate effects of high-velocity spine manipulation on paraspinal activity during flexion–extension trunk movements. Forty nonspecific CLBP patients were randomised into two groups, manipulation ( n = 20) and control ( n = 20). While the manipulation group received high-velocity spine manipulation at the L4-L5 level, the control group remained lying in the same position. EMG-related variables, perceived pain intensity (100 mm VAS) and finger-floor distance were collected before and after spinal manipulation at the L4-L5 level. EMG surface signals from the right and left paraspinal muscles (L5-S1 level) were acquired during trunk flexion–extension cycles. EMG activity during the static relaxation phase was significantly reduced following intervention for the manipulation group but not for the control group. The extension-phase EMG activity was also reduced after manipulation, but the flexion-phase EMG levels remained unchanged. Accordingly, the percent changes in FRR and ERR were significantly larger for the manipulation group compared to the control. The results suggest that a high-velocity spinal manipulation is able to acutely reduce abnormal EMG activity during the full-flexion static phase and activation during the extension phase.

Methicillin-Resistant Staphylococcus aureus as a Cause of Lumbar Facet Joint Septic Arthritis

Hematogenous septic arthritis of the lumbar facet is a well-recognized although rare1-5 primary infectious entity of the spine. Traditionally, the most commonly implicated organism has been Staphylococcus aureus1,2,6 . Although there have been reports of methicillin-resistant Staphylococcus aureus (MRSA) spondylodiscitis7, methicillin-resistant Staphylococcus aureus as a cause of hematogenous facet joint septic arthritis has not been described, to our knowledge. We report our experience with the treatment of two cases of facet joint septic arthritis due to methicillin-resistant Staphylococcus aureus . The patients were informed that data concerning these cases would be submitted for publication, and they consented. Case 1. A fifty-three-year-old man presented with an eighteen-day history of severe back pain radiating to the left lower limb. He was unable to walk because of the intensity of pain. He had retention of urine, for which he required catheterization. Apart from being a chronic smoker, he had no medical comorbidities. Clinical examination revealed severe tenderness over the left side of the lower back. Neurological examination of the left lower extremity revealed grade-2 (of 5) strength of the extensor hallucis longus and tibialis anterior muscles. Lower extremity sensation and deep tendon reflexes were normal. Rectal examination revealed a lax anal sphincter and an absent bulbocavernosus reflex. Hematological examination showed an erythrocyte sedimentation rate of 77 mm/hr (normal, 6 to 12 mm/hr), a total white blood-cell count of 17.4 × 109/L (normal, 4.3 to 10.8 × 109/L), and a C-reactive protein level of 60 mg/L (normal, <6 mg/L). Plain radiographs were unremarkable. Magnetic resonance imaging demonstrated altered signal intensity in the left L4-L5 facet joint, with fluid causing widening of the joint and extending into the adjacent left paraspinal and psoas muscles (Fig. 1-A). The paraspinal muscle fluid …

Back Pain-Cyclist

HISTORY: 41 yo male cyclist with a back injury 3 months prior, falling onto his right hip when the chain on his bike broke. For a short time after, had some "twinges" in his right lower back & mild stiffness, but his back pain had resolved until 6 weeks ago. He bent down to pick up a 20 lb box with sudden onset of severe pain across his low back. Has since had constant & worsening back pain. Cycles 5-6 days/week with an average of 250 miles/week, but has not been able to go for any rides in the past month due to the pain. Aggravated by bending forward. No radiation down the legs or weakness/numbness in the legs. No bowel or bladder symptoms. No fevers, chills, or weight loss. Seen 11 days prior by his PCP & referred to sports medicine, but came to the ER 2 days prior to his initial consultation when the pain became too severe. He owns an AC company & recently worked with a client 2 weeks ago that required him to shovel some manure. No recent travel. PHYSICAL EXAMINATION: + spinous process tenderness & right greater than left paraspinal muscle tenderness of L3 region. Range of motion mildly limited in all directions due to pain. Neurovascularly intact with normal sensation, strength, & reflexes of his lower extremities. Straight leg raise test negative. DIFFERENTIAL DIAGNOSIS: Lumbar strain Herniated lumbar disc Degenerative process of lumbar spine Spondylosis Infectious process of the lumbar spine Neoplastic process of the lumbar spine TESTS AND RESULTS LS Xrays 5/31/08 anterior & left lateral marginal osteophytes at L2-L3 ?lucency in anterior superior endplate & vertebral body of L3 L2-L3 joint space narrowing CT Lumbar Spine 6/2/08 L2-L3 disc narrowing with sclerosis & irregularity of inferior surface of L2 & superior surface of L3 MRI Lumbar Spine 6/6/08 abnormal marrow signal of L2 & L3 suggesting discitis epidural inflammatory mass of paraspinal soft tissue CBC WNL ESR 27 CT-guided biopsy: Gram stain: moderate WBCs, no organisms Culture: moderate growth of E coli Fungal, AFB, & anaerobic cultures negative HIV, Cocci, & Histoplasma serology negative PPD negative FINAL WORKING DIAGNOSIS: Discitis TREATMENT & OUTCOMES: Treated as an outpatient with Cipro 500 mg BID × 6 weeks Lumbar brace × 1 month Began cycling on the trainer after completing antibiotics. Advance to road cycling in 2 weeks if pain-free.

A Thoracic Disc Herniation Presenting as an Abdominal Hernia

Thoracic disc herniations (TDHs) occur infrequently, accounting for fewer than 1% of all spinal disc prolapses.1 Although most TDHs present initially with radicular pain, others may demonstrate only myelopathic signs and/or, even less often, ipsilateral abdominal muscle weakness.2,3 A 75-yr-old male who had been successfully treated with intermittent split-table pelvic traction for a T12–L1 disc herniation returned a year later with new, abrupt-onset, severe left-flank and abdominal pain. The physical examination revealed a large abdominal-wall hernia (Fig. 1) involving both the left upper- and lower-abdominal quadrants. The straight-leg raising test was unrestricted. Sensory and motor testing and the deep tendon reflexeswere all normal.FIGURE 1: Large abdominal-wall hernia (arrow) with thoracic disc herniation.However, there was a notable reduction in the motor units of the muscular abdominal wall. No long tract signs were observed, and the bowels and bladder were controlled. Electroneuromyography demonstrated 4+ fibrillationand positive waves in the left paraspinal muscle at the T10–T12 levels, without similar findings in the adjacent abdominal muscle. However, there was a notable reduction in motor units in the abdominal musculature. The peroneal motor nerve conductions were normal. Magnetic resonance imaging revealed a large, left T12–L1 disc herniation (Fig. 2). With persistent pain and associated difficulty in walking, the patient was referred to a spinal surgeon and was restarted on split-table intermittent pelvic traction after thermal therapy.FIGURE 2: Thoracic disc herniation (arrow) at T12–L1.With continuing conservative treatment, the patient’s pain slowly remitted. TDHs account for 0.24–0.75% of all disc herniations, with an overall incidence of 1/1,000,000 patients per year.1 This relative paucity of TDHs has been attributed to the stabilizing influence of the rib cage. When thoracic radicular pain is accompanied by myelopathic signs (i.e., hyperreflexia and Babinski reflexes), they mimic the presence of a spinal cord tumor. Although suggestive, an abdominal hernia in the presence of radicular thoracic pain is not pathognomonic evidence of a TDH. Other sources of thoracic root compromise include, among others, diabetes mellitus and/or viral exanthems (i.e., poliomyelitis), as well as herpes zoster.

Lumbar Paraspinal Myonecrosis Following Combined Spinal Epidural Anesthesia - A case report -

A 55-year-old woman received a combined spinal epidural anesthesia for total replacement surgery of the left knee. After surgery, the epidural patient controlled analgesia (PCA) device was acti vated. After the first post-operative day, the patient complained of severe back pain rather than left knee pain in spite of the bolus dose of analgesics via epidural catheter. The epidural catheter was removed and intravenous PCA was initiated. On the 16th post-operative day, the patient's back and knee pain improved; however, the fever did not subside. A blood test revealed increased inflammatory markers in spite of antibiotic therapy. Under the suspicion of epidural abscess, a lumbar magnetic resonance imaging scan was performed and revealed an increase in the signal within left lumbar paraspinal muscle. A prompt debridement and irrigation of the necrotic tissues was performed. The histologic diagnosis was lumbar paraspinal myonecrosis. Subsequent to this corrective procedure, the patient's fever subsided and the inflammatory markers were normalized, except for mild back pain after the surgical repair. (Korean J Anesthesiol 2007; 53: 683～7)

Heterogeneous mechanomyographic absolute activation of paraspinal muscles assessed by a two-dimensional array during short and sustained contractions

Spatial dependency of paraspinal muscle activity was assessed using a new two-dimensional MMG recording system. MMG signals were detected over the left and right paraspinal muscles of 10 volunteers using a grid of 12 accelerometers. During two separate trials subjects maintained a 20° flexed position and held loads that ranged from 0 to 15 kg (in 2.5 kg increments) for 20 s; and 7.5 kg for 6 min. Maps of absolute and normalised (with respect to initial values) average rectified value, mean power frequency, variance and skewness of the power spectral density were obtained from the two-dimensional MMG recordings. For both the short duration and sustained contractions, the MMG absolute average rectified value, mean power frequency, variance and skewness depended on accelerometer location ( P<0.05), while, with the exception of the skewness ( P<0.05), normalised values did not. These results demonstrate both inhomogeneous MMG absolute activity and homogeneous MMG normalised activity in paraspinal muscles for short duration and sustained contractions. Moreover, the effect of accelerometer location on spectral variables confirmed the limited validity of general relationships between MMG spectral changes and motor unit recruitment strategies. This study underlines the importance of using multiple recording sites when assessing back muscle activity.

Neuromuscular control of the head in an isometric force reproduction task: comparison of whiplash subjects and healthy controls

Background context A number of recent scientific publications suggest that patients suffering from whiplash-associated disorders (WADs) exhibit sensorimotor deficits in the control of head and neck movements. Purpose The main objective of the present study was to evaluate if subjects with WADs can produce isometric neck extension and flexion forces with precision, variability, and a mode of control similar to the values of healthy subjects. Study design A control group study with repeated measures. Patient samples Neck force production parameters and neuromuscular control were measured in 17 whiplash and 14 control subjects. The experimental group included subjects who had a history of persistent neck pain or disability after a motor vehicle accident. Outcome measures Pain levels were assessed on a standard 100-mm visual analog pain scale at the beginning and end of the experiment. Each whiplash subject completed the neck disability index and the short-form 36 health survey (SF-36) questionnaire before the experiment. Methods All subjects were asked to exert flexion and extension forces against a fixed head harness. Kinetic variables included time to peak force, time to peak force variability, peak force variability, and absolute error in peak force. Surface electrodes were applied bilaterally over the sternocleidomastoideus and paraspinal muscles. Electromyography (EMG)-dependent variables included EMG burst duration and amplitude using numerical integrated techniques. Results The average time to peak force was significantly longer for whiplash subjects than for the healthy controls. A significant increase in peak force variability was also observed in the whiplash group, and no group differences were noted for absolute error. Heightened muscular activity was seen in both paraspinal muscles, even though it only reached statistical significance for the left paraspinal muscle. Conclusion Our results show that the whiplash subjects involved in the study were able to produce isometric forces with spatial precision similar to healthy controls using a motor strategy in which the time to peak force is increased. This trade-off between spatial precision and time to peak force probably reflects an adaptation aimed at limiting pain and further injuries.

Incidental paravertebral hydatid cyst presenting with neck pain

AbstractHydatidosis is a disease usually found in rural and agricultural communities. Disease may affect any tissue, but hydatid disease of the liver and lung is quite common. Spinal hydatidosis is an uncommon manifestation of the parasite Echinococcus affecting fewer than 1% of patients with hydatid disease. A 45-year-old woman was admitted to our hospital with neck pain and a palpable mass over her lower neck. Magnetic resonance imaging of the cervical region revealed a cystic mass lesion embedded in the left paraspinal muscles. The patient was operated and the lesion was totally excised. Histopathological examination revealed a hydatid cyst. Complete systematic and radiological examination was made to detect any hydatid cyst in the other organs, but no other cysts were found. She received oral albendazole therapy (800 mg daily) for three, 3-week protocols. Control systemic and radiological examinations including the cervical MRI six months after treatment revealed normal findings without any cyst forma...

SHOULDER PAIN AND WEAKNESS - ADVENTURE RACING

HISTORY A 35 year-old right-handed elite adventure racer sustained a left shoulder injury while mountain biking when he collided into a tree with his left anterior shoulder. Three weeks prior he had bruised his left face and strained his left neck when he collided with a tree. The shoulder/neck pain associated with both incidents was mild and resolved within several days. Two weeks following the second tree collision, the patient developed severe left shoulder pain, weakness, and dysesthesias involving the proximal upper extremity immediately following a swimming session. Over the next two week, opiate medication was necessary to control the pain and provide satisfactory sleep. Four weeks later he presented to this clinic with no significant improvement in his symptoms. He denied parasthesias or weakness in the other limbs. He was otherwise in good health. PHYSICAL EXAMINATION Examination in our clinic revealed mild atrophy of the left supraspinatus and infraspinatus muscles with normal active external rotation. Testing of the other muscles in the upper limbs tested revealed normal 5/5 strength. Sensation was intact bilaterally to light touch and pin prick and muscle stretch reflexes were 2+/4 and symmetric ROM of the upper extremities. Manual muscle testing was 4/5 for left shoulder abduction and 3/5 for left shoulder. Palpation revealed no tenderness in the left upper extremity, shoulder girdle or cervical paraspinal muscles. Spurling's test was significant for axial cervical pain, bilaterally. He had a mildly positive impingement sign for the right shoulder. Anterior apprehension test, anterior/posterior load and shift tests, and O'Brien's test were negative. DIFFERENTIAL DIAGNOSIS Rotator cuff tendinopathy or tear. Upper cervical radiculopathy. Suprascapular neuropathy. Brachial neuritis. Upper cervical plexopathy. TESTS AND RESULTS Radiographs of cervical spine and left shoulder: normal, MRI of cervical spine: mild left C6 foraminal stenosis. MRI of left shoulder: no evidence of rotator cuff pathology, spinoglenoid cysts, or labrum tear. Electrodiagnostic testing: – conduction delay of the left suprascapular nerve, with 50% less amplitude in the motor unit potential, compared to the right, – 2+ spontaneous denervation activity in the left supraspinatus and infraspinatus muscles, with mild evidence of reinnervation. – normal conduction study of other peripheral nerves and normal needle electromyography study in other left upper limb and cervical paraspinal muscles. FINAL DIAGNOSIS Left suprascapular neuropathy with some axonal loss. TREATMENT AND OUTCOMES Utilization of NSAIDs and opiates for pain control. Relative rest from physical activity for the next 4 weeks. Physical therapy for strengthening exercises focusing on the supraspinantus and infraspinatus muscles. Return to sports activities by 4 weeks. Patient became pain free within two months. Repeat electrodiagnostic tests 5 months after onset of pain revealed complete reinnervation of the supraspinatus muscle, but incomplete reinnervation of the infraspinatus muscle, which showed continued spontaneous activity and polyphasic motor units. Recovery of full strength of supraspinatus muscle within 8 months, but only moderate recovery of strength of infraspinatus muscle.