Ultrasonographic Validation for Needle Placement in the Tibialis Posterior Muscle.

BACKGROUND: The tibialis posterior (TP) muscle plays an important role in normal foot function. Safe, efficacious therapeutic approaches addressing this muscle are necessary; however, the location of the muscle in the deep posterior compartment can create challenges. PURPOSE: The purpose of this study was to assess the accuracy of needle placement in the TP muscle and determine the needle placement in relation to the neurovascular structures located within the deep compartment. DESIGN: Cross Sectional Study. METHODS: Needle placement and ultrasound imaging were performed on 20 healthy individuals. A 50 mm or 60 mm needle was inserted between 30 - 50% of the tibial length measured from the medial tibiofemoral joint. The needle was inserted in a medial to lateral direction into the right extremity with the patient in right side lying. Placement of the needle into the TP muscle was verified with ultrasound imaging, and the shortest distance from the needle to the posterior tibial artery and tibial nerve was measured. The depth from the skin to the superficial border of the TP muscle was also measured. RESULTS: Ultrasonography confirmed the needle filament was inserted into the TP muscle in all 20 individuals and did not penetrate the neurovascular bundle in any individual. The mean distance from the needle to the tibial nerve and posterior tibial artery was 10.0 + 4.7 mm and 10.2 + 4.7 mm respectively. The superficial border of the TP muscle from the skin was at a mean depth of 25.8 + 4.9 mm. CONCLUSION: This ultrasound imaging needle placement study supports placement of a solid filament needle into the TP muscle with avoidance of the neurovascular structures of the deep posterior compartment when placed from a medial to lateral direction at 30-50% of the tibial length. LEVEL OF EVIDENCE: 2b.

Normative Parameters of Gastrocnemius Muscle Stiffness and Associations with Patient Characteristics and Function.

BACKGROUND: Quantifying muscle stiffness may aid in the diagnosis and management of individuals with muscle pathology. Therefore, the primary purpose of this study was to establish normative parameters and variance estimates of muscle stiffness in the gastrocnemius muscle in a resting and contracted state. A secondary aim was to identify demographic, anthropometric, medical history factors, and biomechanical factors related to muscle stiffness. METHODS: Stiffness of the gastrocnemius muscle was measured in both a resting and contracted state in 102 asymptomatic individuals in this cross-sectional study. Differences based on muscle state (resting vs contracted) and sex (female vs male) were assessed using a 2 X 2 analysis of variance (ANOVA). Associations between muscle stiffness and sex, age, BMI, race, exercise frequency, exercise duration, force production, and step length were assessed using correlation analysis. RESULTS: Gastrocnemius muscle stiffness significantly increased from a resting to a contracted state [mean difference: 217.5 (95% CI: 191.3, 243.8), p < 0.001]. In addition, muscles stiffness was 35% greater for males than females in a resting state and 76% greater in a contracted state. Greater muscle stiffness in a relaxed and contracted state was associated with larger plantarflexion force production (r = .26, p < 0.01 and r = .23, p < 0.01 respectively). CONCLUSION: Identifying normative parameters and variance estimates of muscle stiffness in asymptomatic individuals may help guide diagnosing and managing individuals with aberrant muscle function. LEVEL OF EVIDENCE: 2b Individual Cohort Study. CLINICAL RELEVANCE: What is known about the subject: Muscle stiffness has been shown to be related to individuals with pathology such as Achilles tendinopathy; however, research is sparse regarding normative values of muscle stiffness. Measuring muscle stiffness may also be a way to potentially predict individuals prone to injury or to monitor the effectiveness of management strategies.What this study adds to existing knowledge: This study establishes defined estimates of muscle stiffness of the gastrocnemius in both a relaxed and contracted state in healthy individuals. Myotonometry measures of muscle stiffness demonstrated an increase in stiffness during contraction that varies by sex. Greater gastrocnemius muscle stiffness was associated with increased plantarflexion force production.

Functional and corticomotor changes in individuals with tetraplegia following unimanual or bimanual massed practice training with somatosensory stimulation: a pilot study.

BACKGROUND AND PURPOSE: In individuals with cervical spinal cord injury (SCI), damage to spinal pathways results in deficits of hand function; maladaptive cortical changes further impair function. Unimanual massed practice (MP) training with somatosensory stimulation (SS) has been shown to improve hand function and increase corticomotor excitability after SCI. However, bimanual training may be more beneficial as these individuals have bilateral impairment. We compared clinical and corticomotor changes associated with unimanual versus bimanual MP training, each combined with SS. METHODS: Participants were 13 individuals with chronic tetraplegia who had at least minimal voluntary control of the thenar muscles of 1 hand. The participants were randomly assigned to unimanual MP + SS or bimanual MP + SS. Clinical outcome measures included tests of unimanual (Jebsen Taylor Hand Function Test; JTT) and bimanual hand function (Chedoke Arm and Hand Activity Inventory; CAHAI), sensory function (monofilament test), and pinch grip strength. Neurophysiological outcome measures were corticomotor map area, center of gravity (COG), of the corticomotor map and corticomotor threshold as assessed by transcranial magnetic stimulation. RESULTS: There were no significant differences in outcomes between the unimanual MP + SS versus bimanual MP + SS groups, both groups showed significant improvements in the JTT, CAHAI, and monofilament test. However, trends suggest that the unimanual MP + SS group had greater improvement in the JTT whereas the bimanual MP + SS group had greater improvement on the CAHAI. Functional changes were accompanied by a strong trend toward increased corticomotor map area. DISCUSSION AND CONCLUSION: When combined with SS, both unimanual and bimanual MP training improve hand function and sensation in individuals with tetraplegia. Changes in hand function seem to be associated with increased corticomotor map area.

Cortical reorganization following bimanual training and somatosensory stimulation in cervical spinal cord injury: a case report.

BACKGROUND AND PURPOSE: Deficits in upper-extremity function in individuals with tetraplegia are primarily due to the loss of motor pathways. Detrimental cortical reorganization, however, may create further loss of function. The purpose of this case report is to describe the cortical changes associated with a combination intervention using bimanual massed practice training with somatosensory stimulation. CASE DESCRIPTION: "BR" was a 22-year-old man with C6 tetraplegia and hand impairment who participated in this training intervention for 3 weeks. OUTCOMES: BR demonstrated improvements in sensory function, strength (the force-generating capacity of muscle), and performance of functional hand skills. Following the training, the cortical motor map of the biceps brachii muscle shifted anteriorly and increased in area and volume. DISCUSSION: This is the first documented case in which changes in the size and location of the cortical map were associated with an intervention and improvement in function in an individual with tetraplegia. This case suggests that an intensive training intervention may induce both functional and neurophysiological changes.