Ultrasound shear wave elastography measurement of the deep posterior cervical muscles: Reliability and ability to differentiate between muscle contraction states

The deep posterior cervical muscles (DPCM), specifically the semispinalis cervicis and cervical multifidus, are often impaired in patients with neck disorders and have been assessed by several imaging techniques. Prior ultrasound shear wave elastography (SWE) imaging and reliability assessments of the DPCM were performed utilizing similar positioning as assessments for the more superficial cervical extensors. Our objectives were to describe an SWE imaging technique for the DPCM, establish intra-rater reliability of DPCM SWE, and compare DPCM shear modulus during rest and submaximal contraction in both prone and seated positions in individuals without spinal pain. In sixteen participants, the DPCM was located using B-mode ultrasound, then muscle shear modulus was assessed via SWE at both rest and with contraction against a 2-kg resistance applied at the C2 spinous process. Within-day intra-rater reliability was moderate to good (ICC = 0.70-0.88). The DPCM were stiffer during contraction than at rest in the prone position (p = 0.002), and at rest in sitting versus at rest in prone (p = 0.003). Further research is needed to assess DPCM-specific SWE in symptomatic individuals and compare DPCM shear modulus to electromyography across contraction intensities.

SHORT-TERM EFFECTS OF TRIGGER POINT DRY NEEDLING ON PAIN AND DISABILITY IN SUBJECTS WITH PATELLOFEMORAL PAIN SYNDROME

BACKGROUND

Patellofemoral pain syndrome (PFPS) is a prevalent knee disorder. A novel yet increasingly popular treatment for PFPS is trigger point dry needling (DN).

PURPOSE

The purpose of this study was to determine if DN is more effective at reducing pain and disability than a sham treatment in individuals with PFPS.

STUDY DESIGN

Randomized trial.

MATERIALS/METHODS

Sixty military health care beneficiaries (36 males) with a clinical diagnosis of PFPS were recruited and completed the study. Subjects underwent a standardized clinical examination and were randomized into a DN or sham treatment group. DN treatment consisted of insertion of an acupuncture-like needle into six sites in the quadriceps femoris muscles of the symptomatic lower extremity based on a palpation examination. The sham grouped received a simulated treatment with a sharp object and needle guide tube without puncturing the skin. Self-reports of pain, disability, and overall status were collected before treatment, immediately after treatment and at 72 hours. Data were analyzed with separate 2x2 repeated measures analysis of variance, with independent variables being Group (DN vs. sham) and Time (pre-treatment vs. immediately post-treatment, and pre-treatment vs. 72 hours). The hypothesis of interest in each case was the Group*Time interaction. The alpha-level was set a priori to .05 using 2-tailed tests.

RESULTS

Both groups exhibited a clinically meaningful reduction in pain based on numeric pain rating scale scores immediately post-treatment and at 72 hours, but there was no statistically significant difference between groups (p = 0.219, 0.310). There was no significant difference between groups for any other outcome measures.

CONCLUSION

These data suggest that DN treatment is not more effective than a sham DN treatment at reducing short-term pain and disability in individuals with PFPS when used as an isolated treatment approach.

LEVEL OF EVIDENCE

2.

Clinical and electrodiagnostic abnormalities of the median nerve in Army dental assistants before and after training as preventive dental specialists

PURPOSE

Dentists and dental hygienists have been reported as having a high prevalence of upper-extremity musculoskeletal disorders, including carpal tunnel syndrome. Unfortunately, previous research has not involved the impact of preventive dental specialist training on dental assistants. Therefore, the purpose of this study was to determine the presence of median and ulnar neuropathies in US Army dental assistants before and after training as preventive dental specialists.

METHODS

Thirty-five US Army dental assistants (24 female, 11 male; age range 18-41 years) volunteered for the study. Twenty-eight preventive dental specialist students completed both the pretraining and posttraining data collections. Subjects were evaluated during the first and last weeks of their 12-week course. Subjects completed a history form, were interviewed, and underwent a physical examination. Nerve conduction status of the median and ulnar nerves of both upper extremities were obtained by performing motor, sensory, comparison (unilateral median to ulnar distal motor and sensory latencies), and F-wave nerve conduction studies (NCS). Descriptive statistics for subject demographics and pre to post physical examination and nerve conduction variables were calculated. Chi square (χ²) analysis was also conducted to determine if a significant shift in the prevalence of neuropathies occurred following dental training.

RESULTS

With the exception of comparison studies, pre-NCS and post-NCS electrophysiological variables were normal. Specifically, 9 subjects (26%) involving 14 hands (20%) were found to have meaningful (>1.0 millisecond) delayed median to ulnar distal motor latency comparisons in the pretraining assessment. Additionally, there was no statistically significant shift in the prevalence of electrodiagnostic abnormalities of the median nerve following the 12-week training program (χ²=0.280, P=.60).

CONCLUSION

The prevalence of clinical and electrodiagnostic abnormalities of the median nerve in this sample of US Army dental assistants closely mirrors the prevalence reported for other dental professionals. This study also demonstrates that, for this sample, the 12-week training program did not appear to affect the electrophysiologic status of the median or ulnar nerves.

Development of a clinical prediction rule for classifying patients with patellofemoral pain syndrome who respond to patellar taping

STUDY DESIGN

Predictive validity/diagnostic test study.

OBJECTIVE

To determine the predictive validity and interrater reliability of selected clinical exam items and to develop a clinical prediction rule (CPR) to determine which patients respond successfully to patellar taping.

BACKGROUND

Patellar taping is often used to treat patients with PFPS. However, the characteristics of the patients who respond best to patellar taping intervention have not been identified.

METHODS AND MEASURES

Fifty volunteers (27 males, 23 females) with PFPS underwent a standardized clinical examination. Diagnosis of PFPS was based on the complaint of retropatellar pain that was provoked by a partial squat or stair ascent/descent. Subjects performed 3 functional activities and rated their pain during each activity on a numerical rating scale (NPRS). All subjects received treatment with a medial glide patellar-taping technique and repeated the functional activities and pain ratings. An immediate 50% reduction in pain or moderate improvement on a global rating of change (GRC) questionnaire was considered a treatment success. Likelihood ratios (LRs) were calculated to determine which examination items were most predictive of treatment outcome. Logistic regression analysis identified items included in the CPR.

RESULTS

Twenty-six subjects (52%) had an immediate successful response to the intervention. Two examination items (positive patellar tilt test or tibial varum greater than 5 degrees, +LR = 4.4) comprised the CPR. Application of the CPR improved the probability of a successful outcome from 52% to 83%. Fifty-eight percent of the lower extremity measures were associated with moderate to good reliability (reliability coefficient range, 0.52-0.84). The reliability coefficients for the items that comprised the CPR were 0.49 (patellar tilt) and 0.66 (tibial varum).

CONCLUSION

A CPR was developed to predict an immediate successful response to a medial glide patellar taping technique. Validation of the CPR in an independent sample is necessary before widespread clinical use can be recommended.

Identification of individuals with patellofemoral pain whose symptoms improved after a combined program of foot orthosis use and modified activity: a preliminary investigation

BACKGROUND AND PURPOSE

In patients with patellofemoral pain syndrome (PFPS), the authors determined which aspects of the examination could be used to identify those patients most likely to respond to off-the-shelf foot orthoses and instruction in activity modification.

PARTICIPANTS AND METHODS

Fifty participants were enrolled in the study, and data for 5 individuals were excluded from analysis. Thirty-four men and 11 women completed the study. Participants were given foot orthoses and instructed in activity modification for 3 weeks. A 50% reduction in pain was considered a success. Likelihood ratios (LRs) were computed to determine which examination findings were most predictive of success.

RESULTS

The best predictors of improvement were forefoot valgus alignment of 2 degrees (+LR=4.0, 95% confidence interval [CI]=0.7-21.9), great toe extension of 78 degrees (+LR=4.0, 95% CI=0.7-21.9), and navicular drop of 3 mm (+LR=2.4, 95% CI=1.3-4.3).

DISCUSSION AND CONCLUSION

The results suggest that patients with PFPS who have forefoot valgus alignment of 2 degrees, passive great toe extension of 78 degrees, or navicular drop of 3 mm are most likely to respond favorably to initial intervention with an off-the-shelf foot orthosis and instruction in activity modification.

The accuracy of the Palpation Meter (PALM) for measuring pelvic crest height difference and leg length discrepancy

STUDY DESIGN

Test-retest reliability and validity.

OBJECTIVE

To determine the validity and reliability of the Palpation Meter (PALM).

BACKGROUND

Leg length discrepancy (LLD) has been associated with a variety of musculoskeletal disorders. Therefore, the clinical measurement of LLD has become a routine and important part of the physical examination. The PALM is an instrument that was recently developed to indirectly measure LLD, but little is known about its measurement properties.

METHODS AND MEASURES

Fifteen healthy and 15 symptomatic subjects with suspected LLD participated in this study. Measurements of pelvic crest height difference (PD) were obtained by 2 examiners using the PALM. A standing antero-posterior (AP) radiograph of each subject's pelvis was taken, and PD and LLD (femoral head height difference) were determined from the radiograph for comparison with the PALM values. Intraclass correlation coefficients (ICCs) were calculated to determine the validity and reliability estimates of the PALM.

RESULTS

For all subjects, the validity estimates (ICC2,3) of the PALM for PD were excellent (0.90 for rater 1 and 0.92 for rater 2) when compared with the standing AP radiograph of the pelvis. The PALM was less accurate (ICC2,3 of 0.76 and 0.78 for rater 1 and 2, respectively) as an indirect estimate of LLD. Intrarater reliability for each rater was excellent (ICC3,3 = 0.97 and 0.98) and interrater reliability was very good (ICC2,3 = 0.88).

CONCLUSION

The PALM is a reliable and valid instrument for measuring PD. Clinicians should consider this convenient, cost-effective clinical tool as an alternative to radiographic measurement of pelvic crest height difference.

Contractile properties of the tongue's genioglossus muscle and motor units in the rat

The contractile characteristics of individual mammalian tongue muscles have rarely been investigated, in contrast to spinal cord-innervated and extraocular muscles. Therefore, whole muscle and motor unit contractile forces, plus muscle fiber types, were studied in the genioglossus, the major protrusor muscle, of the rat tongue. The muscle, exclusively composed of fast-contracting units, could be activated from rostroventral hypoglossal nucleus sites only. The following figures represent the means of the contractile measures. Whole muscle twitch tension was 7.02 g, contraction time was 14.22 ms, fusion frequency was 104 Hz, maximum tetanic tension was 37.22 g, and fatigue index was 0.72. Single motor unit twitch tension was 45. 9 mg, contraction time was 11.7 ms, fusion frequency was 94.8 Hz, maximum tetanic tension was 241.95 mg, and fatigue index was 0.68. The genioglossus muscle appeared qualitatively similar to the rat styloglossus muscle, one of the two major retractor muscles of the tongue. The delineation of motor unit contractile characteristics in tongue muscle is important in our understanding of the control of tongue movement.

Whole-muscle and motor-unit contractile properties of the styloglossus muscle in rat

Investigations of whole muscle and motor-unit contractile properties have provided valuable information for our understanding of the spinal cord and extraocular motor systems. However, no previous investigation has examined these properties in an isolated tongue muscle. The purpose of this study was to determine the contractile properties and muscle fiber types of the rat styloglossus muscle. The styloglossus is one of three extrinsic tongue muscles and serves to retract the tongue within the oral cavity. Adult male Sprague-Dawley rats (n = 19) were used in these experiments. The contractile characteristics of the whole styloglossus muscle (n = 9) were measured in response to stimulation of the hypoglossal nerve branch to the muscle. The average twitch tension produced was 3.30 g with a mean twitch contraction time of 13.81 ms. The mean maximum tetanic tension was 19.66 g and occurred at or near the fusion frequency, which averaged 109 Hz. The styloglossus muscle was resistant to fatigue [fatigue index (F. I.) = 0.76]. In separate experiments (n = 7), the contractile characteristics of 37 single motor units were measured in response to extracellular stimulation of hypoglossal motoneurons. The twitch tension generated by styloglossus motor units averaged 35.7 mg, and the mean twitch contraction time was 12.46 ms. The mean fusion frequency was 92 Hz. Maximum tetanic tension averaged 177.8 mg. Styloglossus single motor units were resistant to fatigue (F. I. = 0.74). The sites of stimulation that yielded a contractile response in the styloglossus muscle were consistent with the location of the styloglossus motoneuron pool reported in earlier anatomy studies. Muscle fiber typing was determined in three animals based on the myofibrillar ATPase reaction at pH 9.8, 4.6, and 4.3. The styloglossus muscle was composed of approximately 99% type IIA fibers with a few scattered type I fibers present in the study sample. On the basis of the combined findings of the physiology and histochemistry experiments, the styloglossus muscle appeared to be a homogeneous muscle composed almost exclusively of fast, fatigue-resistant motor units. These properties of the styloglossus muscle and its motor units were compared with findings in other rat skeletal muscles.

The effects of spinal flexion and extension exercises and their associated postures in patients with acute low back pain

STUDY DESIGN

A prospective randomized clinical trial compared the effects of flexion and extension back exercises and postures among soldiers with acute low back pain.

OBJECTIVE

To compare the immediate effects of back exercise on functional status, spinal mobility, straight leg raising, pain severity, and treatment satisfaction, and to determine whether spinal exercise during the acute stage of low back pain reduces recurrent episodes of low back pain.

SUMMARY OF BACKGROUND DATA

Conflicting reports exist concerning the efficacy of spinal flexion and extension exercises in patients with low back pain of varying duration. Poor study design and lack of functional outcomes characterize many of these studies.

METHODS

One-hundred-forty-nine subjects with acute low back pain received flexion exercise and posture (n = 57), extension exercise and posture (n = 62), or no exercise or posture (n = 30) for 8 weeks. Outcomes were assessed 1, 2, 4 and 8 weeks after treatment onset. A questionnaire assessed the recurrence of low back pain 6-12 months after study entry.

RESULTS

Flexion and extension exercise groups did not differ in any outcome over 8 weeks. After 1 week, both exercise groups had reduced disability scores, a higher proportion returning to work, and fewer subjects with a positive straight-leg raise compared with the control group. There was no difference among groups regarding recurrence of low back pain after 6-12 months.

CONCLUSIONS

There was no difference for any outcomes between the flexion or extension exercise groups. However, either exercise was slightly more effective than no exercise when patients with acute low back pain were treated.