Functional MR imaging of the human cervical spinal cord

BACKGROUND AND PURPOSE

Although research with functional MR imaging of the brain has proliferated over the past 5 years, technical limitations, such as motion, chemical shift, and susceptibility artifacts, have impeded such research in the human spinal cord. The purpose of this investigation was to determine whether a reliable functional MR imaging signal can be elicited from the cervical spinal cord during simple motor activity.

METHODS

Subjects performed three different motor tasks that activate different segments of the spinal cord. Gradient-echo-planar imaging on a 1.5-T clinical unit was used to image cervical spinal cords of human subjects. Another group of subjects was imaged while performing isometric exercise to study the relationship between the blood oxygenation level-dependent (BOLD) signal and applied force.

RESULTS

Task-dependent BOLD activity was detected in all subjects. Signal amplitude varied between 0.5% and 7%. Moreover, a linear relationship was found between the applied force and the signal amplitude during isometric exercise. While regions of activation were distributed throughout the spinal cord, concentrated activity was found in the anatomic locations of expected motor innervation.

CONCLUSION

The functional MR imaging signal can be reliably detected with motor activity in the human cervical spinal cord on a 1.5-T clinical unit. The location of neural activation has an anatomic correspondence to the myotome in use. The strength of the BOLD signal is directly proportional to the level of muscular activity.

The relationship between the functional abilities of patients with cervical spinal cord injury and the severity of damage revealed by MR imaging

BACKGROUND AND PURPOSE

The appearance of the damaged spinal cord after injury correlates with initial neurologic deficit, as determined by the American Spinal Injury Association grade and manual muscle test score, as well as with recovery, as assessed by manual muscle test scores. The purpose of this study was to determine whether the presence of spinal cord hemorrhage and the size and location of spinal cord edema on MR images is predictive of functional recovery in survivors of cervical spinal cord injury (SCI).

METHODS

The degree of damage to the cervical spinal cord was measured on the MR images of 49 patients who underwent imaging within 72 hours of sustaining SCI. The effects of hemorrhage and length/location of edema on changes in the value of the motor scale of the functional independence measure (FIM) were assessed on admission to and discharge from rehabilitation.

RESULTS

Patients without spinal cord hemorrhage had significant improvement in self-care and mobility scores compared with patients with hemorrhage. There was no significant effect of spinal cord hemorrhage on changes in locomotion and sphincter control scores. The rostral limit of edema positively correlated with admission and discharge self-care scores and with admission mobility and locomotion scores. Edema length had a negative correlation with all FIM scales at admission and discharge.

CONCLUSION

The imaging characteristics of cervical SCI (hemorrhage and edema) are related to levels of physical recovery as determined by the FIM scale. Imaging factors that correlate with poor functional recovery are hemorrhage, long segments of edema, and high cervical locations.

Neurologic outcome of early versus late surgery for cervical spinal cord injury

STUDY DESIGN

A prospective analysis evaluating neurologic outcome after early versus late surgery for cervical spinal cord trauma.

OBJECTIVES

The study was conducted to determine whether neurologic and functional outcome is improved in traumatic cervical spinal cord-injured patients (C3-T1, American Spinal Injury Association grades A-D) who had early surgery (<72 hours after spinal cord injury) compared with those patients who had late surgery (>5 days after spinal cord injury).

SUMMARY OF BACKGROUND DATA

There is considerable controversy as to the appropriate timing of surgical decompression and stabilization for cervical spinal cord trauma. There have been numerous retrospective studies, but no prospective studies, to determine whether neurologic outcome is best after early versus late surgical treatment for cervical spinal cord injury.

METHODS

Patients meeting appropriate inclusion criteria were randomized to an early (<72 hours after spinal cord injury) or late (>5 days after spinal cord injury) surgical treatment protocol. The neurologic and functional outcomes were recorded from the acute hospital admission to the most recent follow-up.

RESULTS

Comparison of the two groups showed no significant difference in length of acute postoperative intensive care stay, length of inpatient rehabilitation, or improvement in American Spinal Injury Association grade or motor score between early (mean, 1.8 days) versus late (mean, 16.8 days) surgery.

CONCLUSIONS

The results of this study reveal no significant neurologic benefit when cervical spinal cord decompression after trauma is performed less than 72 hours after injury (mean, 1.8 days) as opposed to waiting longer than 5 days (mean, 16.8 days).

Use of shoulder flexors to achieve isometric elbow extension in C6 tetraplegic patients during weight shift

The anterior deltoid muscle has been found to be active during elbow extension in normal volunteers and in C6 tetraplegic patients lacking a functional triceps. Using surface electromyography (EMG) on normal volunteers and on patients with spinal cord injury (SCI) at the C6 motor level, we evaluated whether the anterior deltoid and biceps brachii muscles are active during closed chain elbow extension in a simulated weight shift position. Thirteen normal volunteers performed isometric contractions at 5 submaximal levels of force ranging from 4-25 kg. Six SCI patients performed isometric contractions at force levels of 20%, 40%, 60%, 80% and 100% maximum voluntary contraction (MVC). Surface EMG over the right biceps, triceps, and anterior deltoid muscles was recorded for each participant and the root mean square (rms) electromyographic activity level for each muscle was determined at each level of force. Statistical analyses using repeated ANOVA with Tukey HSD post-hoc tests were performed for each level of force. The results indicated increasing rms activity of the triceps and anterior deltoid muscles with increasing force in normal volunteers to a significant degree (P < 0.05). SCI patients showed significant increasing activity of the anterior deltoid with increasing force, but showed minimal triceps rms activity. In both groups, the biceps showed minimal rms activity. SCI patients exhibited significantly greater rms activity of the anterior deltoid at low force compared with normal volunteers. The results suggest that the anterior deltoid aids in isometric elbow extension during a simulated weight shift maneuver.

Forecasting motor recovery after cervical spinal cord injury: value of MR imaging

PURPOSE

To determine whether magnetic resonance (MR) imaging quantification of cervical spinal cord damage improves the prediction of motor recovery after spinal cord injury.

MATERIALS AND METHODS

The extent of cervical spinal cord injury was measured on MR images obtained in 104 patients (aged 17-70 years) within 72 hours of spinal cord injury. The effects of hemorrhage and edema length on motor outcome were examined for at least 12 months.

RESULTS

Patients with spinal cord hemorrhage had significantly lower upper and lower extremity motor scores at the time of injury and at 12 months than did patients without hemorrhage (P < .001). There was little recovery of lower extremity function even in patients without hemorrhage. Upper extremity motor function improved significantly in all patients (P < .001); patients without hemorrhage showed the largest improvements. The motor recovery rates for patients without hemorrhage were 0.74 (upper extremities; range, 0-1) and 0.55 (lower extremities; range, 0-1); those for patients with hemorrhage were 0.31 (range, 0-1) and 0.091 (range, 0-1). Stepwise multiple regression analyses indicated that MR information on hemorrhage and the length of edema increases the ability to predict clinical outcome by 16%-33% over that with initial clinical scores alone.

CONCLUSION

An initial MR imaging evaluation of the spinal cord after spinal cord injury provides supplemental prognostic information on the recovery of motor function in the upper and lower extremities.

Spinal cord injury and bladder recovery

OBJECTIVE

To investigate whether spinothalamic tract preservation and posterior column sparing are predictors of neurogenic recovery of bladder function after spinal cord injury (SCI). DESIGNS AND PARTICIPANTS: In a retrospective review, the initial perianal pinprick sensation (S4.5 dermatomes) and position sense of the great toes were examined and correlated with bladder function at 1 year after SCI in 19 consecutive spinal cord injured patients (age 18 to 68 years), Frankel A-D, with spinal injury (level C-4-T-12). All patients were admitted to the Regional Spinal Cord Injury Center of Delaware Valley (RSCIDDV) within 72 hours of injury between July 1990 and June 1991 and were available for a 1-year follow-up evaluation.

MAIN OUTCOME MEASURES

The correlation of initial perianal pinprick and great toe position sensation with bladder management approximately 1 year after SCI.

RESULTS

During the initial 72 hours, 10 of the 19 patients had positive perianal pinprick sensation and 9 did not feel the pin. Eight patients had positive great toe position sense, and 11 had no proprioception. At the 1-year follow-up visit, 7 of the 10 patients with initial preserved perianal pinprick were voiding volitionally, whereas none of the 9 patients who did not have pinprick voided volitionally at 1-year after SCI. Six of the 8 with initial preserved great toe position sense were voiding volitionally at 1 year, but only 1 of the original 11 without initial toe position sense was voiding volitionally.

CONCLUSIONS

Both perianal pinprick sensation and toe position sense are sensitive in predicting return of bladder function. Although both tests have positive predictive value, their negative predictive values are much more noteworthy. A patient without initial position sense of the great toes will likely not regain volitional voiding, whereas a patient without initial perianal pinprick sensation will definitely not regain volitional voiding.

Strength post-spinal cord injury: myometer vs manual muscle test

This study was designed to compare changes in strength after spinal cord injury (SCI) with the use of a hand held myometer to the manual muscle test (MMT). Eighty-eight C4-C8 Frankel A-D tetraplegic subjects were tested at various times up to 2 years post-SCI. Elbow flexor strength on successive examinations were grouped according to their early and later MMT scores (3.5 with no change in MMT. 3.5 to 4.0, and 3.5 to 4.5; 4.0 with no change in MMT, 4.0 to 4.5, and 4.0 to 5.0; 4.5 with no change in MMT, and 4.5 to 5.0). For each group, later myometric measurements (MYO) were expressed as percents of their earlier MYO and were analyzed using paired Student t-tests. Later MYO were 116, 205, 232% (P > 0.05, P < 0.002, P < 0.05) of their earlier MYO for groups 3.5 with no change in the MMT, 3.5 to 4.0, and 3.5 to 4.5 respectively. Later MYO were 140, 139, 191% (P < 0.05, P < 0.02, P < 0.0001) of their earlier MYO for groups 4.0 with no change in MMT, 4.0 to 4.5, and 4.0 to 5.0 respectively. Later MYO were 127 and 126% (P < 0.01, P < 0.02) of their earlier MYO for groups 4.5 with no change in MMT and 4.5 to 5.0 respectively. In conclusion the hand held myometer detected changes in muscle strength not detected by the MMT.

Intrauterine onset of a mononeuropathy: peroneal neuropathy in a newborn with electromyographic findings at age one day compatible with prenatal onset

Mononeuropathies are unusual at birth, and electromyographic (EMG) definition the first day of life has not been reported previously. Although neonatal mononeuropathies may be related to obstetric complications, prenatal mechanisms also merit consideration. We report an infant, born with a peroneal neuropathy, whose EMG was performed 18 h after birth. An isolated peroneal nerve lesion with lack of compound muscle action potential and the presence of fibrillation potentials, confined to the tibialis anterior muscle, suggested a primary intrauterine mechanism for this mononeuropathy. Because of an infant's small size, the temporal profile used in adults for appearance of EMG signs of wallerian degeneration may not apply. Inaccurate conclusions may result if the EMG standards for timing adult nerve injury are applied to newborns. To our knowledge, previous published cases of neonatal mononeuropathies have not included babies whose first EMG was performed before age 4 days. Therefore, an EMG study shortly after birth needed to be accomplished if strong support for the hypothesis of a prenatal onset were to be generated. Our findings are compatible with an intrauterine onset of this baby's peroneal neuropathy.

Future ambulation prognosis as predicted by somatosensory evoked potentials in motor complete and incomplete quadriplegia

OBJECTIVE

The purpose of this prospective study was to determine the efficacy of tibial somatosensory evoked potentials (SEPs) in predicting ambulation in tetraplegic individuals.

DESIGN

This was a prospective study of a cohort of cervical spinal cord-injured patients who had SEPs recorded within 72 hours to 2 weeks post-SCI and whose ambulation outcome was followed up to 2 years post-SCI.

SETTING

Regional Spinal Cord Injury (SCI) Center.

PATIENTS

All male and female subjects admitted to the center from 1988 to 1991 between the ages of 15 and 60 years who demonstrated C4 through T1 complete and incomplete acute SCIs were asked to participate in this study.

MEASUREMENTS

The tibial nerve cortical SEPs were graded as either present or absent. The waveforms were also graded as less than 0.5 microV or > or = 0.5 microV. Quadriceps strength plus touch and pin sensation were tested within 72 hours to 2 weeks post-SCI. Ambulation was rated as absent, exercise, household, or community. The ambulatory and clinical status were assessed monthly for 3 months, and then at 6, 12, 18, and 24 months post-SCI. Statistical analysis using the two-tailed Fisher's exact test was performed relating the initial clinical and SEP data to ambulation outcome up to 24 months post-SCI.

RESULTS

All 13 subjects with a right and/or left quadriceps manual muscle test (MMT) greater than 0/5 became ambulatory. Of the 9 subjects with an initial bilateral quadriceps MMT = 0/5, only 1 recovered enough lower limb function to ambulate (p = .0001). One of the 7 subjects with absent touch sensation in the lower limbs became ambulatory, whereas 14 of the 15 subjects with touch sensation present became ambulatory (p = .002). All 7 subjects with absent pin sensation in the lower limbs were nonambulatory, and 14 of 15 subjects with pin sensation present became ambulatory (p < .0001). Of the 9 subjects with bilaterally absent cortical SEP waveforms, 2 became ambulatory. Twelve of the 13 subjects with a cortical SEP wave present became ambulatory (p = .0015). Of the 10 subjects with a cortical SEP wave amplitude less than 0.5 microV, only two became ambulatory, whereas all 12 subjects with an amplitude > or = 0.5 microV became ambulatory (p = .00014). In no subject did the SEP predict future ambulation where the clinical examination did not also predict recovery of ambulation.

CONCLUSION

Both the early postinjury clinical evaluation and the SEP predicted ambulation outcome to a significant degree, but the SEP offered no additional prognostic accuracy over that provided by the clinical examination.

Traumatic focal posterior tibialis muscle denervation

The purpose of this case presentation is to demonstrate posterior tibialis muscle (PTM) denervation as a cause of traumatic plantarflexion inversion weakness. In a 42-year-old woman, severe pain, swelling, and ecchymosis over the medial aspect of her left ankle developed after she twisted it while playing tennis. Plantarflexion inversion weakness developed (grade 3/5). The strength of all other muscle groups of the lower extremity was normal. Her pin and light touch sensation were normal in the left lower extremity. Deep tendon reflexes were equal and active at both knees and ankles. A magnetic resonance image of the left leg, ankle, and foot performed 1 month after injury demonstrated an intact posterior tibialis tendon behind the medial malleolus and edema-like increased signal intensity in the PTM on the T1-weighted image consistent with denervation. On electromyographic testing, there were continuous fibrillation and positive sharp wave potentials in every site tested in the PTM without any voluntary motor unit activity. The left extensor hallucis, left gastrocnemius, and lumbar paraspinal muscles were normal. In conclusion, combined magnetic resonance imaging and electromyographic studies supported denervation of the PTM as the cause of plantarflexion inversion weakness, rather than posterior tibialis tendon rupture in this patient.

Neuromuscular disease: rehabilitation and electrodiagnosis. 1. Anatomy and physiology of nerve and muscle

This article of the Self-Directed Physiatric Education Program to assist practitioners and trainees in physical medicine and rehabilitation identifies the anatomy and physiology of nerve, neuromuscular junction, and muscle as they relate to rehabilitation of diseases affecting these structures. Structural relationships of the spinal roots, peripheral nerves, motor units, and muscle fibers are outlined, with structural, functional, and electrodiagnostic correlations. Features of nerve and muscle biochemistry and physiology are reviewed as they relate to common neurological diseases, age, and sex. The spontaneous potentials, motor unit activities, and nerve conduction abnormalities found in diseases of nerve and muscle also are described.

Elbow extension using anterior deltoids and upper pectorals in spinal cord-injured subjects

OBJECTIVE

Surface electromyography was used to identify muscles active in isometric elbow extension in spinal cord-injured (SCI) patients.

DESIGN

Tetraplegic subjects participated in this cohort study aimed at identifying some of the muscles that are active during isometric elbow extension.

SETTING

Regional Spinal Cord Injury (SCI) Center.

PATIENTS

The patients had to have a C6 motor level on the right side (wrist extensor > or = 3/5) with 0/5 or 1/5 elbow extensor muscle power. Of 32 patients who could be contacted by telephone, 6 eventually were able to make it to the SCI center for testing.

MEASUREMENTS

The patients performed a series of isometric elbow extension contractions of 25%, 50%, and 75% of maximum voluntary contraction (MVC) as measured by a force transducer. Surface electromyography (EMG) of the right elbow extensor, anterior deltoid, and upper pectoral muscles was measured using the root mean square (rms) of the amplitude of the motor unit activity as the parameter of muscle activity. Statistical analyses were performed using a repeated analysis of variance (ANOVA) with Tukey post-hoc HSD for each percentage of MVC.

RESULTS

For each muscle tested, there was significantly (p < 0.05) greater rms activity for each percentage of MVC except between 50% and 75% MVC of the elbow extensor muscle. However, the elbow extensor muscle had minimal EMG activity when compared with the amplitude of the rms activity of the anterior deltoid and upper pectoral muscles for each percentage of MVC.

CONCLUSION

The results of the study suggest that the anterior deltoid and the upper pectoral muscles exert an isometric elbow extension force for C6 quadriplegic patients.

Transcranial magnetic stimulation: cortical motor maps in acute spinal cord injury

This investigation examined the motor pathways of four, C5-6 spinal cord injured (SCI) patients within 6-17 days of injury. Mapping of the motor cortex was achieved by transcranial magnetic stimulation (TMS) applied to the scalp. Motor evoked potentials were recorded from target muscle groups (Biceps brachii and Abductor pollicis brevis m.). Evidence of an expanded cortical map of the preserved contralateral biceps muscle was demonstrated in these patients as early as 6 days. These findings suggested that early motor re-organization may occur following acute cervical spinal cord injury in man.

Wrist strength measured by myometry as an indicator of functional independence

The purpose of this study was to show that independence of self care activities of motor complete quadriplegic patients related better to the force of contraction of the wrist extensor (WE) muscles measured by a hand held myometer than to the manual muscle test (MMT) for grades 3 to 5. The patients (n = 24), identified by having unilaterally or bilaterally functional WE muscle (MMT > or = 3/5) with bilateral elbow extensor (EE) muscles < 3/5, were evaluated at 2 to 6 months after injury for four feeding activities utilizing the Quadriplegia Index of Function (QIF). We found 54% were independent drinking from a cup, 58% using a spoon or fork, 13% cutting food, and 23% pouring liquids. Comparisons were made between right, left, and bilateral mean myometry scores and median MMT scores for each of the QIF activities. The independent group of patients had myometry scores 54 to 140% greater (p < 0.05) than those patients dependent in the self care activity except when the right or left WE myometric score was analyzed for cutting food (p = 0.1). MMT comparisons showed no significant median score differences in any activity performed. There were no patients with only one WE muscle > or = 3/5 (n = 9) who were able to cut food or pour liquids independently. In conclusion, myometry appeared to be a better indicator than the MMT for some self care activities evaluated utilizing the Quadriplegia Index of Function.

Biceps vs extensor carpi radialis recovery in Frankel grades A and B in spinal cord injury patients

Clinical literature suggests that the wrist extensors show a trend of achieving functional strength earlier than the biceps after spinal cord injury (SCI). Basic research, however, demonstrated that proximal muscles recover earlier than distal muscles after partial denervation. The purpose of this study was to compare biceps to extensor carpi radialis (ECR) recovery of muscle strength in 39 motor complete cervical SCI patients. Biceps (n = 19) and ECR (n = 20) with a 72 hour or 1 week motor grade of 1/5 were compared. Testing was performed weekly for 1 month, and again at 2, 3, 6 and 12 months post injury. The median recovery times to increase one motor grade were: biceps = 2 months and ECR = 2.5 months (p < 0.3). The median recovery times to increase two motor grades were: biceps = 2 months and ECR = 3 months (p < 0.4). In conclusion, there was no significant difference between the rates of recovery of the biceps and the ECR up to 12 months post SCI.

Predicting recovery of motor complete quadriplegic patients. 24 hour v 72 hour motor index scores

This paper reports motor index scores on motor complete (Frankel A, B), C4-T1, quadriplegic patients at admission, 72 h to 1 week and 6 months after spinal cord injury. This study is designed to test the hypothesis that the 72-h to 1-week motor index score (referred to as 72-h motor score) is superior to motor scores recorded within the first 24 h in predicting 6 month motor scores. Twenty-seven quadriplegic subjects, ages 15-70 years, were followed prospectively using manual muscle test to document motor recovery. Biceps, wrist extensors, triceps, flexor digitorum profoundus and first dorsal interossei were tested within 24 h, 72 h-1 week and 6 months after injury to comprise the motor index score. Average total motor scores for both upper extremities at admission were 14.0, at 72 h 13.9, and at 6 months 19.3 (ANOVA, P < 0.01). Total bilateral motor scores changed by 5.3 from admission to 6 months and by 5.4 from 72 h to 6 months. No significant difference existed between the admission and post 72-h motor score in predicting the 6-month motor score (Newmann-Keuls P > 0.05). Thus, despite significant change in motor score after spinal cord injury, both admission and 72-h motor scores equally predicted 6 month motor recovery of C4-T1 motor complete quadriplegic patients.

Magnetic resonance imaging related to neurologic outcome in cervical spinal cord injury

The purpose of this study was to examine the relationship between the initial intramedullary hemorrhage, as seen by magnetic resonance imaging (MRI), and the neurologic deficit and eventual neurologic outcome of acute cervical spinal cord injured subjects. MRI and motor assessments were performed on 24 subjects with motor complete (Frankel A & B) and incomplete (Frankel C & D) injuries. Recovery was determined by evaluating an initial and a final motor power following spinal cord injury (SCI), as defined by the manual muscle test (grade 1-5) and motor index score (MIS). Results showed that all 15 subjects having hemorrhage had motor complete injuries (Frankel A & B). Sixteen percent of the muscles in the upper extremities and 3% of the muscles in the lower extremities in these 15 subjects improved to a grade of > or = 3/5 at the final evaluation post-SCI. In comparison, of the nine subjects not having hemorrhage, eight had motor incomplete injuries (Frankel C & D) and had 73% and 74% of muscles improving in the upper and lower extremities, respectively. In addition, a change in MIS from initial to final evaluations showed a significant difference between subjects with hemorrhage and subjects without hemorrhage (upper extremities: p = .002 and lower extremities: p = .0001). In conclusion, the initial MR image and neurologic assessment correlated with motor power recovery.

Recovery of the extensor digitorum longus muscle in the rat following L4 nerve sectioning

The purpose of this study was to define the time course and the extent of recovery of muscle weight and tension in the extensor digitorum longus (EDL) muscle following partial denervation in nine-week-old male rats (300 to 325 g). The L4 nerve underwent unilateral sectioning while the opposite side served as a sham-operated control. The muscle weight and tension of the control and the partially denervated group were examined at two (n = 15), eight (n = 15), 12 (n = 15), and 16 (n = 15) weeks after L4 nerve sectioning. The partially denervated muscle weights as a percentage of respective controls were 58.6%, 56.1%, 68.4%, and 61.9% at two, eight, 12, and 16 weeks after L4 nerve sectioning. There was no significant difference (p > 0.05) between these percentages at the respective time intervals. The tetanic tensions compared with their respective matched controls were 14.5%, 32.8%, 50.0%, and 32.4% at these respective time intervals (p < 0.05). The muscle weight (MW) and muscle weight/body weight (MW/BW) of the partially denervated side as a percentage of its contralateral control remained unchanged throughout the duration of the experiment. The twitch tension (Pt), tetanic tension (Po), Pt/Po, and the Po/MW of the partially denervated muscle relative to its matched control increased between the second and the eighth week post-partial denervation (p < 0.05). After the eighth week post-L4 nerve sectioning, there was no further increase in these parameters.(ABSTRACT TRUNCATED AT 250 WORDS)

Assessing selfcare status in quadriplegia: comparison of the quadriplegia index of function (QIF) and the functional independence measure (FIM)

The purpose of this study was to compare the quadriplegia index of function (QIF) to the functional independence measure (FIM) in assessing the daily performance of selfcare activities by individuals with cervical spinal cord injury. This study evaluated feeding, grooming and bathing activities in 22 C4-C7, Frankel A-D spinal cord injury patients between 3 and 12 months postinjury. The manual muscle test (MMT) was performed on 17 of these subjects during the same window of time as the QIF and the FIM. An upper extremity motor score (UEMS) was derived from the MMT. In order to relate motor power to functional ability, the UEMS was used as a measure of neurological function to test the hypothesis that the QIF scores are more highly correlated to motor power than are the FIM scores for this population. Spearman coefficients were calculated to correlate the QIF, the FIM and the UEMS. For the bathing and grooming categories, both the QIF and the FIM showed significant and similar correlations to the UEMS. For the feeding category, however, the QIF had a significantly better correlation to the UEMS than did the FIM (Rho = 0.90 vs 0.53, p < 0.01). Use of the QIF feeding scale may allow the detection of changes in function as individuals recover that the FIM scale would miss. Further evaluation of the remaining selfcare and mobility scales is needed. Modification of the FIM with more sensitive portions of the QIF would improve the discriminative ability of outcome studies and program evaluations.

Closed reduction of traumatic cervical spine dislocation using traction weights up to 140 pounds

The purpose of this study was to demonstrate that Gardner-Wells skull tong traction up to 140 lb was both safe and effective in reducing dislocation, without fractures, of facet joints involving the C4-C7 vertebral bodies when applied by experienced practitioners in a spinal cord injury center under close scrutiny. Twenty-four awake patients were selected for the study (age range, 16-82 years). These patients were evaluated for the number of millimeters (7-17 mm) of dislocation as measured from the posterior aspect of the superior vertebral body to the posterior aspect of the inferior vertebral body at the level of injury. The maximum weight required to produce the reduction of the facet joints and the time from the onset of traction were recorded. The patients' neurologic status was monitored before traction, after each increment in weight applied, and after reduction. Careful examination of motor function and sensation was done and recorded at each interval. The 24 patients with cervical spine dislocation of the facet joints underwent successful reduction with traction weights (range, 10-140 lb). Seventeen patients required weights of more than 50 lb. The traction procedures lasted for a period of 8-187 minutes per procedure. Worsening neurologic status did not occur in any of the patients involved in this study.(ABSTRACT TRUNCATED AT 250 WORDS)

Pin sensation as a predictor of extensor carpi radialis recovery in spinal cord injury

The purpose of this prospective study was to determine if initial preservation of C5 pin sensation could predict extensor carpi radialis (ECR) motor recovery in the zone of partial preservation after spinal cord injury (SCI). The study compared initial C5 pin sensation and initial ECR strength as predictors of ECR motor recovery after C4 and C5 SCI. The initial motor and sensory evaluation was done less than seven days after injury. Motor power was graded from absent (0/5) to normal strength (5/5). Pin sensation was graded as absent (0/2) decreased (1/2) or normal (2/2). The manual muscle test was performed weekly to four weeks and than at three, six, and 12 months after injury. An ECR muscle grade of > or = 3/5 was defined as recovery. C5 pin sensation at the lateral antecubital fossa significantly correlated with ECR recovery to > or = 3/5 (p < 0.001). Only two of nine subjects with absent C5 pin sensation recovered ECR to > or = 3/5, whereas 14 of 15 subjects with 1/2 or 2/2 C5 pin sensation had ECR motor recovery to > or = 3/5. All ten subjects with 1/5 or 2/5 initial ECR strength had ECR motor recovery. Five of six subjects with 0/5 initial ECR strength and subsequent ECR recovery to > or = 3/5 were found to have C5 pin preservation. In conclusion the presence of 1/5 to 2/5 initial ECR strength or 1/2 or 2/2 C5 pin sensation were highly significant predictors of ECR motor recovery to > or = 3/5 in C4 and C5 motor complete quadriplegic subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Changes in nerve conduction and Pi/PCr ratio during denervation-reinnervation of the gastrocsoleus muscles of rats

The purpose of this investigation was to study the changes in nerve conduction and phosphate metabolites of the gastrocsoleus muscles of rats during denervation-reinnervation. Sixteen male Sprague-Dawley rats underwent unilateral crush-denervation of the left sciatic nerves at the sciatic notch. Six rats were used for measurement of motor conduction latency and action potential amplitude of the gastrocsoleus muscle by stimulating the sciatic nerve at one, two and eight weeks after nerve crush. The other ten rats were designated for evaluation of the ratio of inorganic phosphorous (Pi) to phosphocreatine (PCr) by a 31P-phosphoenergetic spectrometer at two weeks and eight weeks after nerve crush. None of the sciatic nerves showed conduction to the gastrocsoleus at one or two weeks after nerve crush. At eight weeks postcrush, the motor conduction latency returned to within normal limits, whereas the action potential amplitude was only 55% of the normal. For the eight-week period of study, the Pi/PCr ratio of the normal control muscles ranged between 0.09 +/- 0.02 and 0.11 +/- 0.02 (mean +/- SD). The denervated muscles showed an increase of Pi/PCr ratio by 54% at two weeks postcrush, compared to the respective contralateral control sides. The ratios returned to the normal value by eight weeks postcrush. In summary, these data suggested that the metabolic recovery of the crush-denervated muscle followed the same pattern as the parameters of nerve conduction.

Relationship between two measures of upper extremity strength: manual muscle test compared to hand-held myometry

One hundred and twenty-two individuals with spinal cord injuries at levels C4-6, Frankel classifications A through D, were evaluated to determine the relationship between the manual muscle test (MMT) and hand-held myometry as accurate methods for measuring muscular strength. More specifically, this study attempted to define a range of myometry scores that could be correlated with discrete MMT grades. It also investigated which of the two modalities (MMT or hand-held myometry) is the best reflection of improvement in muscle strength over time. Sequential motor strength examinations using both modalities were performed at 72 hours, one week, and two weeks post SCI and then one, two, three, four, six, 12, 18, and 24 months post injury. The data analyses included calculations of Spearman ranked correlations, analyses of variance, and linear regressions. Results showed that 22 of 24 correlations between MMT and myometry were significant at p values less than .001. The range of myometry measurements for a particular MMT grade appears to be most specific for MMT scores less than 4 (ie, poor-plus to good), and less specific for MMT scores greater than or equal to 4. The results of this study also indicate that myometry measurements detect increases in strength over time, which are not reflected by changes in MMT scores.

Extensor carpi radialis recovery predicted by qualitative SEP and clinical examination in quadriplegia

This prospective study examined the efficacy of the qualitative somatosensory evoked potential (SEP) and the initial clinical neurologic evaluation to predict motor power recovery of the extensor carpi radialis muscle (ECR). Twenty three C5-6 Frankel A-D spinal cord injured (SCI) subjects had SEPs of the median nerve (MN) and superficial radial nerve (SRN) performed within 72 hours to one week post injury. The MN and SRN cortical SEPs were qualitatively graded as either present or absent. Fifteen subjects whose initial ECR muscle strength was less than or equal to 3/5 and eight subjects whose muscle strength was greater than 3/5 were followed up to 12 to 18 months post injury for improvement in ECR muscle strength. The subject's ECR strength was evaluated by manual muscle testing (MMT) at 72 hours, weekly for three weeks, monthly for three months, and then at six, 12, and 18 months. The pin sensation at the C-5 dermatome was also tested at the above intervals and graded as either present or absent. A one tail Fisher Exact test compared the presence or absence of the MN and SRN SEPs to the recovery of the ECR to 3/5. The same one tail test also compared the presence or absence of the 72 hour C-5 pin sensation and the 72 hour MMT to the ECR recovery. Among the 15 subjects with an initial MMT of less than or equal to 3/5, ten subjects had successful ECR recovery (greater than 3/5); 5 did not. The C-5 pin sensation correctly predicted ECR recovery in all subjects studied (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Sensory root level recovery in patients with Frankel A quadriplegia

This prospective study was designed to demonstrate root level recovery of sensation in the zone of partial preservation in patients with C4 through C8, Frankel A spinal cord injuries. Subjects were evaluated for pin (n = 18) and light touch (n = 17) sensation. All subjects had normal sensation at the level of injury, and decreased or absent sensation at all levels caudal to that level within the zone of partial preservation; they had absent sensation at all levels below the zone of partial preservation. After the initial examination, patients were evaluated weekly for four weeks, and then at 2, 3, 6, 12, 18, and 24 months postinjury. Six of 18 patients recovered pin sensation and five of 17 recovered light touch within three months of injury. Most subjects who recovered had injuries from C5 through C8. Eleven of 12 C4 patients did not recover pin sensation, and 11 of 11 failed to recover light touch. However, five of six C5 to C8 patients recovered both pin and light touch. The p values (Fisher-Exact tests) for the C4 vs C5 to C8 groups were .004 and .001 for pin and light touch, respectively. In conclusion, approximately 30% of the total population improved one sensory root level, with the C5 to C8 injured patients comprising the majority of this improvement.

Course of motor recovery in the zone of partial preservation in spinal cord injury

Thirty-nine C4 to C6 motor complete Frankel A or B spinal cord injured subjects were included in this prospective study to determine the course of recovery in the zone of partial preservation (ZPP) during the first 6 months postinjury. Subjects had initial manual muscle testing and neurologic examination between 3 and 7 days postinjury. Subjects whose most rostral key muscle in the ZPP had a motor power of grade 1 or 1+/5 (group 1, n = 22) were compared with subjects whose most rostral key muscle had a motor power of grade 2 or 2+/5 (group 2, n = 17). Subjects had manual muscle testing weekly for 1 month and then monthly for 6 months postinjury. Comparisons were made for recovery to: (1) grade 3/5; (2) grade 4/5; (3) an increase of one grade; and (4) an increase of two grades. Analyses were made at monthly intervals by the Fisher Exact test and between median times of recovery by the Kruskal-Wallis Ranking test. There was earlier recovery to grade 3/5 for group 2. At one month 11 of 17 (65%) group 2 subjects had reached grade 3/5 compared with 4 of 22 (18%) group 1 subjects (p less than 0.01). At 2 months postinjury, 14 of 17 (82%) group 2 subjects versus 10 of 22 (45%) group 1 subjects had reached grade 3/5 strength (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Recovery of zero-grade muscles in the zone of partial preservation in motor complete quadriplegia

This prospective study was designed to demonstrate root level recovery in the zone of preservation by examining muscles with an initial strength of grade 0/5 in 32 motor complete (Frankel A and B) patients who had cervical spinal cord injury at the C4 through C7 levels. The biceps (C5), extensor carpi radialis (C6), triceps (C7), and flexor digitorum profundus (C8) muscles were used as key muscles when their strength at the initial manual muscle test, which was performed between three and seven days postinjury, was grade 0/5 and the muscle innervated by the cord segment directly rostral to that innervating the key muscle (grade 0/5) was grade greater than or equal to 3/5. If the biceps muscle was used, C4 pin sensation was required to be normal. Further manual muscle tests were performed weekly for four weeks, and then at 2, 3, 6, and 12 months postinjury. None, 6%, 17%, 35%, and 43% of the patients recovered to grade greater than or equal to 3/5 by 1, 2, 3, 6, and 12 months postinjury, respectively. It was also noted that in 86% of our patients, improving to grade greater than or equal to 1/5 by one month postinjury was a predictor of recovering to grade greater than or equal to 3/5 by 12 months postinjury (p less than .002). Similarly, in 100% of our patients, improving to grade greater than or equal to 2/5 by three months postinjury was a predictor of recovering to grade greater than or equal to 3/5 by 12 months postinjury (p less than .001).(ABSTRACT TRUNCATED AT 250 WORDS)

Motor power differences within the first two weeks post-SCI in cervical spinal cord-injured quadriplegic subjects

The purpose of this study was to confirm the clinical impression that motor power significantly changed within the first 2 weeks after a spinal cord injury (SCI) and to determine the time for motor power assessment within the first 2 weeks post injury that best correlated with motor power determined 6 months post-SCI. Our hypothesis was that within the first 2 weeks postinjury, the manual muscle test (MMT) scores would change significantly from the < or = 24 h examination and that the post-24 h evaluations of strength would have a higher correlation with the 6 month measure of motor outcome than the evaluation of strength performed < or = 24 h after SCI. The biceps, extensor carpi radialis, triceps, flexor digitorum profundus, and interosseous muscle strength was measured in 40 subjects using the MMT (muscles graded 0/5 to 5/5) at < or = 24 h, 72 h, 1 week, 2 weeks, 3 months, and 6 months post-SCI. Upper extremity motor index scores (MIS) obtained at the four testing periods within 2 weeks of injury were analyzed using a Friedman analysis of variance with Duncan's post-hoc tests to identify significant differences. Separate analyses were performed on subgroupings of the total sample based on the strength of the most rostral key muscle having less than antigravity strength. There were three groups evaluated: initial MMT 0/5 (n = 22), initial MMT 1-1.5/5 (n = 17), and initial MMT 2-2.5/5 (n = 13).(ABSTRACT TRUNCATED AT 250 WORDS)

Spinal cord injury syndrome with motor sparing in the absence of all sensation

This paper describes the anatomic basis for the unusual presentation in a spinal cord injured subject of preservation of motor power in the absence of all sensation. The patient was examined at four hours, and daily thereafter, after a motorcycle accident in which he was thrown over the handle bars. He had trace ankle dorsi and plantar flexors, but light touch, pin, position, and vibratory sensation were absent below the level of C4 bilaterally. There was no physical evidence to differentiate whether he suffered a flexion or extension injury. Cervical spine films showed no evidence of fracture or dislocation, but anterior and posterior osteophytes involving C3 to C4, C4 to C5, and C5 to C6 were present. Magnetic resonance imaging showed evidence of cervical cord edema at C3 to C4 with possible hemorrhage and severe spinal stenosis at C3 to C4 and C4 to C5. This patient received a compression injury with resulting classic anterior spinal artery syndrome. Because of his spinal stenosis with a decreased anterior-posterior (AP) diameter of the canal, the posterior circulation was also compromised. The extensive pial anastomotic network provided relative sparing of the most peripheral components of the lateral corticospinal tracts. This case report demonstrates a unique clinical picture that cannot be anatomically classified by current American Spinal Injury Association (ASIA) standards as central cord syndrome. It can be explained by the lamination of the ascending and descending tracts in relation to the vascular supply of the cervical cord in conjunction with the narrowing of the AP diameter of the canal due to spinal stenosis.

Postpoliomyelitis muscle weakness: a prospective study of quadriceps strength

The objective of this study was to evaluate the presence of progressive postpoliomyelitis muscle weakness (PPMW) in affected individuals 20 to 40 years after the initial polio infection. Over a three-year period, the isometric and isokinetic strength of the quadriceps femoris muscle was studied in seven symptomatic patients with previous poliomyelitis (mean = 38.3 years from infection) to determine if quadriceps strength decreased during the three years. Each patient had a quadriceps affected by polio on one side and a clinically nonaffected quadriceps on the contralateral limb. The maximal isometric force and the peak isokinetic force of the affected quadriceps (AQ) and nonaffected quadriceps (NQ) muscles were tested on a computerized isokinetic dynamometer machine at six-month intervals. Isometric force increased significantly, by 29% per year (p less than .02) in the AQ and by 14% per year (p less than .05) in the NQ. Paired analysis to determine the change in strength between the affected and nonaffected muscles for the isometric data showed a mean nonsignificant increase in the AQ of 14% per year (p = .01). The change in peak isokinetic force demonstrated a significant increase in the AQ of 35% per year (p less than .05); whereas, the NQ peak isokinetic force increased 15% per year which was not statistically significant. Paired analysis to determine the change in strength between the affected and nonaffected muscles for the isokinetic data showed a nonsignificant relative increase in the AQ of 20% per year (p less than .06).(ABSTRACT TRUNCATED AT 250 WORDS)

The 72-hour examination as a predictor of recovery in motor complete quadriplegia

Twenty-nine C4 to C7 motor-complete spinal cord injured subjects were evaluated to determine whether the manual muscle test (MMT) performed within 24 hours of injury or at 72 hours after injury better predicts short-term functional muscle recovery. A single muscle in the zone of injury that had a muscle grade between 1 and 3, inclusive, was evaluated serially in each patient from admission to three months. Increase in muscle strength to grade 4 or better was defined as success. Outcomes were evaluated by the Fisher exact test. Using the less-than-24-hour MMT, 12 of 17 subjects with grade 3 muscle strength vs four of 12 subjects with grade 1 or 2 muscle strength achieved success (p greater than .05). Using the 72-hour MMT, all 11 subjects with grade 3 muscle strength vs five of the 18 subjects with less than grade 3 muscle strength achieved success (p less than .001). Short-term functional muscle recovery in the zone of injury in cervical motor-complete quadriplegia is better predicted by the 72-hour MMT than by the less-than-24-hour MMT.

Cosmetic, functional, independent: self-help aids

Self-help orthotics have been developed to assist functional activities for high-level spinal cord injured patients. The goal of rehabilitation has been to do this with as little intrusion on independence and cosmesis as possible. This paper describes devices to help a patient with C6 quadriplegia independently place his own utensils and eat with an almost normal appearance. The new self-help aids are made from standard silverware, a rivet, and two one-eighth-inch Kydex loops. The loops are riveted centrally on the utensil, allowing for free rotation. The device was evaluated on a patient with C6, complete quadriplegia. The subject demonstrated independence in donning and doffing the device and in eating with an almost normal appearance.

Motor evoked potentials and central motor conduction: studies of transcranial magnetic stimulation with recording from the leg

To determine central conduction times in the corticospinal pathways of humans using magnetic stimulation, we have developed a method for consistently recording conduction times between the motor cortex and the L4-5 level of the spinal cord. In 30 subjects, motor evoked potentials (MEPs) were recorded from the tibialis anterior muscle following contralateral motor cortex and peroneal nerve stimulation. In 18 of these subjects, the L4-5 intervertebral space was stimulated. The stimuli consisted of single, painless, short-duration magnetic pulses. In 12 subjects, measurements were made during voluntary ankle dorsiflexion, and during vibration of the TA tendon at rest. All subjects had measureable MEP latencies of 30.3 +/- 2.2 msec (mean +/- S.D.). The central motor conduction time (CMCT) was calculated using both a direct as well as an indirect method. The direct method in 18 subjects had a mean value of 16.2 +/- 1.7 msec, while the indirect method in all 30 subjects was 13.8 +/- 1.8 msec. No significant correlation of the CMCT was found with either age or height in these subjects. Ankle dorsiflexion significantly reduced the MEP latency and increased the amplitude, whereas vibration of the TA tendon significantly increased the amplitude alone. We conclude that MEPs may be consistently and painlessly measured in the lower extremity using magnetic stimulation in adults. Facilitation of the MEPs was produced more consistently by voluntary contraction than by vibratory stimulation of the tibialis anterior muscle tendon. Finally, CMCT was independent of both age and height in our study population.

Spontaneous electromyographic potentials in chronic spinal cord injured patients: relation to spasticity and length of nerve

Nine patients with complete cervical spinal cord injury (SCI) had their vastus medialis, tibialis anterior, and gastrocnemius muscles evaluated with an electromyographic (EMG) examination in the acute (four to eight weeks) and chronic (more than one year) phases. The hypothesis that spontaneous EMG activity changes with time was assessed. During the chronic phase evaluation, a conduction study was performed to rule out peripheral nerve damage, and the amount of reflex activity was assessed on a scale of 0 to 5 (0 = areflexia; 5 = greater than 5 beats of clonus) to estimate the amount of spasticity. Subjects demonstrated normal conduction through the sensory (sural nerve) and/or motor segments of the peroneal and tibial nerves. In the acute phase, each muscle had spontaneous activity with no significant variation between different muscles of the same patient. In the chronic phase, there was a positive correlation between the degree of spontaneous activity in a muscle and the length of its axon (p less than .01) and a negative correlation between the amount of spontaneous activity and the degree of reflex activity (p less than .01). Specifically, the lower motor neuron in the chronic phase of an SCI seems to behave much like an axonopathy where the degree of spontaneous EMG activity is dependent on the length of the axon, with the additional concept that spontaneous activity is inhibited by spasticity.

Recovery of strength at the zone of injury in motor complete and motor incomplete cervical spinal cord injured patients

This study compared the time of recovery at the zone of injury between motor complete (Frankel A and B) and motor incomplete (Frankel C and D) cervical spinal cord injured patients for the biceps (C5), extensor carpi radialis (C6), and triceps (C7) muscles. Manual muscle testing was performed initially three to seven days postinjury, then weekly for four weeks, and then monthly for six months. Subjects between the ages of 15 and 70 years with C4, C5, C6, or C7 neurologic levels were classified according to whether their selected muscle was greater than 0/5 and less than 3/5 grade (n = 32) or greater than or equal to 3/5 grade (n = 28) at initial evaluation. Subjects were further classified based on their Frankel score. Motor incomplete patients with muscle strength less than 3/5 had an average time of recovery to grade 3/5 of 0.9 months (median = 2 weeks), and all seven patients achieved grade 3/5 by two months postinjury. Motor complete patients had an average time of recovery to grade 3/5 of 1.8 months (median = 2 months), and 18 of 25 patients achieved grade 3/5 by two months postinjury (p = 0.1). For muscles greater than or equal to 3/5, motor incomplete subjects had an average time for improvement of one full grade of 1.5 months (median = 2 months), and motor complete subjects had an average time for improvement of one grade of 2.3 months (median = 1 month, p = 0.1).(ABSTRACT TRUNCATED AT 250 WORDS)

Disseminated fat necrosis: a rehabilitation challenge

Disseminated fat necrosis (DFN) is a rare complication of pancreatic disease characterized by subcutaneous nodules, visceral effusions, osseous intramedullary fat necrosis, and arthritis. The rehabilitation of a 33-year-old patient with DFN is described here. The patient had a history of alcoholic pancreatitis for which she underwent a subtotal pancreatectomy. Three months later she developed subcutaneous nodules and migratory polyarthralgias. The diagnosis of DFN as the etiology of her arthritis was confirmed by synovial fluid analysis; in addition, magnetic resonance imaging of her long bones revealed multiple marrow infarcts. She was nonambulatory and required assistance with transfers because of severe joint pain. Treatment included local ice, prednisone, methadone, instruction on joint preservation and proper body mechanics, and ambulation with weight-bearing as tolerated with an assistive device. At the patient's discharge, her joint inflammation was clinically improved but not resolved, and she was independent in transfers and ambulation with a walker for short distances. Despite ongoing inflammation, functional improvement was accomplished through a rehabilitation program emphasizing partial weight-bearing ambulation rather than strengthening exercises.

Deep vein thrombosis: prophylaxis in acute spinal cord injured patients

The purpose of this prospective, randomized study was to evaluate the efficacy of low-dose heparin, alone or in combination with electric stimulation, in the prevention of deep vein thrombosis (DVT) in C2 to T11 motor complete and incomplete-preserved motor, nonfunctional spinal cord injured patients. The tibialis anterior and gastrocnemius-soleus muscle groups were stimulated bilaterally, using 50 microsecond pulses given at 10Hz with a four-second "on" and an eight-second "off" cycle for 23 hours daily over a 28-day period. Forty-eight patients, less than two weeks after injury, were randomly assigned to saline placebo (n = 17), low-dose heparin (5,000U, subcutaneous every eight hours) (n = 16), and low-dose heparin plus electric stimulation (n = 15). A normal 125-I fibrinogen scan and impedance plethysmography were required for entry into the study. Surveillance for DVT was evaluated by daily 125-I fibrinogen scanning. Venography was performed to confirm a positive impedance plethysmography and/or 125-I fibrinogen scanning tests for two consecutive days and at the completion of the study. The incidence of DVT was 8 of 17 in the placebo group, 8 of 16 in the low-dose heparin group, and 1 of 15 in the electric stimulation plus low-dose heparin group. The use of electric stimulation plus low-dose heparin significantly (p less than 0.05) decreased the incidence of DVT compared to the other treatments.

Overwork-induced axonal hypertrophy in the soleus nerve of the rat

Effect of overwork, induced by synergistic tenotomy (bilateral tenotomy of the gastrocnemius and the plantaris muscles) of the soleus muscle, was evaluated on areas of the large myelinated axons (LMA) (greater than 19.5 micron 2), in the soleus nerve (the tibial nerve branch innervating the soleus muscle) of the rat. Three lots (n = 12-16) of young adult male (body weight of 275 to 325 g), Sprague-Dawley rats were used. One lot of 16 animals was kept as normal, while the other two underwent bilateral L4 or L5 spinal nerve sectioning. Six to seven animals each from the normal, L4-, and L5 neurectomized animals underwent bilateral synergistic tenotomy of the soleus so that the soleus was retained as the sole plantar-flexor of the ankle joint. The remaining animals were kept as normal or neurectomized control groups. Thus, the six groups studied were normal control (n = 9); normal synergistically tenotomized (n = 7); L4 neurectomized control (n = 8); L4 neurectomized and synergistically tenotomized (n = 6); L5 neurectomized control (n = 8); and L5 neurectomized and synergistically tenotomized (n = 7). Seven days after surgery, the soleus muscles were used to evaluate the muscle weights. The soleus nerves were evaluated for the number plus areas of the LMA by computerized planimetric procedures. The data revealed a 13.9% (p less than 0.05) increase in areas of the LMA in the L5 neurectomized control group; whereas the L5 neurectomized and synergistically tenotomized group showed a 39.6% (p less than 0.01) increase in areas of the LMA.(ABSTRACT TRUNCATED AT 250 WORDS)

Muscle atrophy in rheumatoid arthritis

The purpose of this paper is to describe some research opportunities in the area of muscle atrophy secondary to arthritis. Future research should utilize quantitative methods of evaluating muscle atrophy such as computerized tomography or ultrasonography. The gross muscle atrophy should be further characterized by muscle fiber type measurements. These techniques as well as biochemical determinations should be utilized to identify mechanisms of muscle atrophy as well as determine ideal methods for reversing muscle atrophy and weakness.

Wrist extensor recovery in traumatic quadriplegia

Wrist extensor recovery is of major functional significance in many quadriplegic patients. In this retrospective study, we investigated a method for prognosticating wrist extensor recovery and the underlying mechanisms for improvement in strength. Thirty-five quadriplegic patients at the C4, C5, and C6 neurologic levels, admitted over a four-year period, were examined at one week, two months, and eight months postinjury for biceps and wrist extensor strength. Initial biceps strength was compared to final wrist extensor strength. All 16 C5 patients whose initial biceps strength was grade 3 showed wrist extensor improvement to grade 3; only three of 16 C4 patients showed the same improvement. We concluded that initial biceps strength is a reliable indicator of wrist extensor recovery, and most, if not all, C5 neurologic patients will gain one full motor level. This improvement may be due to compensatory factors, such as overwork hypertrophy and peripheral sprouting of nerves within the muscle, rather than to recovery of a root level.

Muscle atrophy and histopathology of the soleus in 6-mercaptopurine-treated rats

In this study, male and female Sprague-Dawley rats were treated neonatally with 6-MP-treatment (2 mg/kg s/c, between 2 and 22 days after birth) and evaluated at six months of age. Compared to the normal controls, the 6-MP-treated male and female rats showed similar sciatic nerve conduction to the soleus. However, there was a significant muscle atrophy (57-60%, P less than 0.01) and a decrease in areas of the type I (42-54%, P less than 0.05) and type II (41-71%, P less than 0.01) muscle fibers. The number of type II fibers declined significantly (7.4-14.8%, P less than 0.05). It is proposed that the soleus muscle atrophy and histopathology in 6-MP-treated rats is unrelated to nerve conduction defects and may be related to growth inhibition caused by an interference of the drug during normal differentiation of muscle fibers.

Capillary fiber ratio and electrolyte content of compensatory hypertrophied rat soleus

Capillary-to-fiber ratio and the content (mu moles/g muscle) of Na, K, Mg, Ca and Zn was measured in compensatory hypertrophied (CH) soleus muscles of adult Sprague-Dawley rats. The soleus hypertrophy was induced by unilateral tenotomy of the gastrocnemius and the plantaris muscles. Seven days after synergistic tenotomy the compensatory hypertrophied Soleus muscles showed no difference in the capillary-fiber ratio, Sr-extractable calcium ([Ca]Ext.) or the total content of Na, K, Mg and Zn. However, compared to the contralateral control side, the CH muscles showed an increase in the wet muscle weight (31.6%, P less than 0.01) and a significant decline (57.1%, P less than 0.05) in the residual calcium ([Ca]Res.) and 43.2% (P less than 0.05) decrease in the total calcium ([Ca]Total) content. It is concluded that during compensatory hypertrophy of skeletal muscles, the residual Ca reserves are significantly depleted, which may lead to a lower isometric tension generation in the muscle.

Overwork effect on partially denervated rat soleus muscle

The purpose of this study was to assess the effect of overwork induced by synergistic tenotomy on the muscle weight (MW) and isometric tetanic tension (Po) of the partially denervated rat soleus muscle. Forty-nine young adult male Sprague-Dawley rats were divided into six groups (n = 5 to 9): normal control (N), normal synergistically tenotomized (N-ST), L4 denervated control (L4), L4 denervated synergistically tenotomized (L4-ST), L5 denervated control (L5), and L5 denervated synergistically tenotomized (L5-ST). Bilateral L4 or L5 root transections produced partial denervation. To yield soleus muscle overwork the gastrocnemius and plantaris muscles were bilaterally tenotomized in all ST groups at the time of denervation. The soleus MW and Po were examined seven days following denervation and tenotomy. Compared to their respective controls, there was increased MW in the N-ST (43.5%, p less than 0.01) and the L4-ST (38.6% p less than 0.01) groups. The L5-ST group showed no significant change in MW compared to the L5 group. Tetanic tension was increased only in the N-ST group. The L4-ST and L5-ST groups did not show any change in Po compared to their respective controls. Despite marked denervation, the L5 group did not show any atrophy as compared to the N group, suggesting passive stretch of the denervated muscle fibers, hypertrophy of the innervated muscle fibers and peripheral sprouting prevented the loss of MW due to denervation. Overwork in this markedly denervated group could not produce any increase in the MW or Po.(ABSTRACT TRUNCATED AT 250 WORDS)

Electrical stimulation of sciatic nerve of rats after partial denervation of soleus muscle

The purpose of this study was to determine the effect of electrical stimulation of the sciatic nerve on the recovery of the weight and tension of partially denervated rat soleus muscle. Electrodes were implanted unilaterally adjacent to the sciatic nerve in 30 adult female Wistar rats. Fifteen rats underwent bilateral partial nerve section (PNS) of the sciatic nerve to stimulate the plantar flexors. Both the normal and partially nerve sectioned animals were stimulated unilaterally with 4 ms, 2-4 mA current given at 10 pulses per second. Groups of five normal and five partially denervated animals were stimulated for two, four or eight hours per day, five days per week for six weeks. The soleus muscles were evaluated for muscle weight (MW), twitch (Pt) and tetanic (Po) tension, contraction time (CT) and fiber areas of the type 1 and type 2 fibers. The MW, Pt, Po, CT and area of the type 1 and 2 muscle fibers of the normal soleus muscles were 114 +/- 15 mg, 21 +/- 4 mg, 95 +/- 20 mg, 95 +/- 21 ms, 1532 +/- 84 microns m2 and 1267 +/- 136 microns m2 respectively. The electrical stimulation had no effect on the normal soleus muscles. The MW, Pt, Po, CT and area of type 1 and 2 muscles fibers of the partially denervated control soleus muscles were 59 +/- 12 mg, 9 +/- 4 mg, 22 +/- 14 mg, 104 +/- 32 ms, 1028 +/- 514 microns m2, and 849 +/- 292 microns m2 respectively. Two hours of electrical stimulation significantly increased the MW (87 +/- 17 g), Pt (17 +/- 6g), and Po (49 +/- 23 g) but not the type 1 and 2 fiber areas.(ABSTRACT TRUNCATED AT 250 WORDS)

Muscle atrophy and histopathology of the soleus in 6-mercaptopurine-treated rats

This study was conducted to examine the histochemical changes occurring due to neonatal 6-mercaptopurine (6-MP) treatment (2 mg/kg, sc, between 2 and 22 days after birth) in the slow-twitch muscle (soleus) of adult male and female rats. At 6 months of age, the control and the 6-MP-treated rats were evaluated for the sciatic nerve conduction to the soleus and for the soleus atrophy and histopathology of the type I (slow-twitch) and type II (fast-twitch) muscle fibers. Compared to the normal controls, the 6-MP-treated male and female rats showed similar sciatic nerve conduction to the soleus. However, there was a significant muscle atrophy (57-60%, P less than 0.01) and a decrease in fiber areas of the type I (42-54%, P less than 0.05) and type II (41-71%, P less than 0.01) fibers. The number of type II fibers declined significantly (7.4-14.8%, P less than 0.05). It is proposed that the soleus muscle atrophy and histopathology in 6-MP-treated rats is unrelated to nerve conduction defects and may be related to growth inhibition caused by an interference of the drug during normal differentiation of muscle fibers.