Gerald J. Herbison

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 (mena, 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).

Spinal cord injury: prognosis for ambulation based on quadriceps recovery

The purpose of this study was to determine if early recovery of quadricep muscle strength post spinal cord injury (SCI) is a useful predictor of future ambulation. Seventeen C4-T10 motor incomplete (Frankel C) spinal cord injured patients adimitted to our center between March 1988 and April 1990 were examined within 72 hours to one week post injury. All patients had initial quadricep strengths ^ 2/5 in both legs. Strength in the strongest quadricep was followed prospectively at intervals from admission to one year post injury. Recovery time to a > 3/5 quadricep was established for each patient. Patients were categorized into 2 groups: FA (n = 11) were those patients who achieved functional ambulation and NA (n = 6) were those subjects who were nonambu-lators. Functional ambulators were defined as those patients who were able to walk in the household and/or the community while non ambulators were those who either did not ambulate or did so only for exercise. All patients (n = 9) who achieved a > 3/5 quadricep by 2 months post SCI became functional ambulators whereas in the group of 8 patients who did not achieve a > 3/5 by 2 months, only 2 became functional ambulators. This result was found to be significant using a point-by-serial correlation with /?<0.05. In conclusion, motor incomplete spinal cord injured patients who recovered to a > 3/5 quadricep strength by 2 months post injury had an excellent prognosis for subsequent ambulation by 6 months post injury.

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.

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 tetraplegie 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 anlayzed using paired Students 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.

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

SummaryThis 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.

Effect of overwork during reinnervation of rat muscle.

Abstract Changes in muscle weights, protein content, and conduction latencies to gastrocnemius along with muscle weights of soleus and plantaris were investigated in adult rats at 72 hr, 1, 2, 3, 4, and 6 wk after bilateral sciatic nerve crush. The effect of overwork (induced by tenotomy of synergistic muscles) initiated in pre- and postreinnervation periods was evaluated in soleus and plantaris muscles. Evoked potentials by nerve conduction were lost at 72 hr and reappeared at the end of 3 wk. Muscle weight and protein content in the gastrocnemius decreased from 72 hr until 2 wk postdenervation. Muscle weights of plantaris and soleus followed the same trend. From 3 to 6 wk postdenervation all three muscles gained in weight and the protein content of gastrocnemius continued to increase to normal accompanied by shortened latency to indirect stimulation, although the latter returned only to 75% of normal. The return of nerve conduction 3 wk after neuronal damage indicates that functional reinnervation takes place between 2 and 3 wk after the nerve crush. The overwork, induced in the soleus and plantaris muscles by elimination of synergists, at 2 wk (Group II) and 3 wk (Group I) after denervation, showed contrasting results in protein content. Overwork in Group I significantly increased muscle weight, absolute amount of sarcoplasmic, myofibrillar and stromal proteins, and fiber diameters in both soleus and plantaris. Muscle weight, sarcoplasmic protein, and myofibrillar protein decreased in both muscles of Group II. However, fiber diameter exceeded control values only in the plantaris and was associated with an increased number of fibers exhibiting low myosin ATPase (pH 9.4) activity. The results of this study suggest that overwork begun within the period of reinnervation may be more beneficial than when initiated before this event.

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.

Effect of swimming on reinnervation of rat skeletal muscle

There are no studies that define the optimum intensity or time to begin exercising reinnervating muscle. Through overwork of reinnervating muscle, accomplished by synergistic tenotomy, we developed a working hypothesis. This hypothesis was tested on a physiological model. In the present study, the sciatic nerve of five groups of rats was crushed. One group served as the control and the remaining animals were exercised by swimming with weights attached to their tails for one or two hours each day (early reinnervation group) or four weeks (late reinnervating group) after crush denervation. The evaluation of muscle weights, fibre types, and protein concentration indicate that intense swimming (two hours every day) does not enhance the repair of reinnervation muscle. An evaluation of total proteins suggests that a high workload may be hazardous in the early phase of reinnervation. This study tends to confirm the hypothesis that when there are too few contractile units, as presumably is the case in early reinnervation, exercise inhibits the reinnervation process.

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 Fishers 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.

Effect of activity and inactivity on reinnervating rat skeletal muscle contractility

Abstract Adult female rats underwent bilateral sciatic nerve crush for the purpose of evaluating the effect of activity and inactivity on the recovery of the contractile properties of the soleus and plantaris muscles. Treadmill training at 35% grade and bilateral cast immobilization of the hind limbs were started 2 or 3 weeks after sciatic nerve crush, when reinnervation is known to commence. The isometric twitch ( P t ) and tetanic ( P o ) tensions and time to peak tension ( C t ) were performed at an optimal length ( L o ) to give the maximum in vitro P t in a physiologic cell filled with aerated Ringers lactate solution ( p H 7.2) at 34 to 35°C. The plantaris P t , P o , and C t and soleus P o and C t were unaffected by the exercise, but recovery of the soleus P t was significantly impaired by the treadmill training. Cast immobilization delayed the recovery of the P t and C t more in the soleus than the plantaris. In conclusion, extremes of activity or inactivity retarded, but did not prevent, the recovery of the slow more than the fast muscle during reinnervation.