Factors associated with return to play following conservative treatment for lumbar spondylolysis among young athletes: A retrospective case series using structural equation modeling.

INTRODUCTION: Lumbar spondylolysis is the most common underlying cause of lower back pain (LBP) in young athletes. Conservative treatment methods are often used to reduce pain and promote healing. Several parameters may affect the duration of conservative treatment, such as the time to return to play (RTP), patient behavior, and physical parameters; however, no study has comprehensively assessed the factors that affect the time to RTP. OBJECTIVES: This study aimed to determine the factors associated with the time required for RTP among young athletes with early-stage spondylolysis receiving conservative treatment using structural equation modeling (SEM). METHODS: In this retrospective case series, 137 young athletes (128 males and 9 females, aged 9-18 years) with early-stage lumbar spondylolysis were enrolled. All patients were examined using plain radiography and magnetic resonance imaging and treated conservatively (sports cessation, wearing a corset, therapeutic exercises, and low-intensity pulsed ultrasound radiation). SEM was used to investigate the factors affecting the time to RTP in these patients. RESULTS: The final model included the following factors: spondylolysis laterality, symptom duration, lower-extremity flexibility, treatment interval, patient adherence, and residual LBP. SEM revealed that patient adherence to physician orders (p < 0.01), treatment interval (p < 0.001), and spondylolysis laterality (p < 0.001) contributed directly to shortened RTP. CONCLUSION: Patient adherence is essential for reducing the time to RTP among young athletes receiving conservative treatment for early-stage spondylolysis.

Microwave hyperthermia treatment increases heat shock proteins in human skeletal muscle.

OBJECTIVE: To test the hypothesis that microwave hyperthermia treatment (MHT) increases heat shock proteins (HSPs) in the human vastus lateralis muscle. METHODS: Four untrained healthy male volunteers participated in this study. The lateral side of the thigh of one leg (heated leg) was heated with a microwave generator (2.5 GHz, 150 W) for 20 min. At 1 day after the MHT, a muscle sample was taken from the heated leg. A control sample was taken from the unheated leg on another day of the MHT. For both legs, HSP90, HSP72 and HSP27 levels were compared. RESULTS: The HSP90, HSP72 and HSP27 levels in heated legs were significantly higher than those in control legs (p<0.05). CONCLUSIONS: Application of MHT can increase the levels of several HSPs in human skeletal muscle.

Changes in muscle temperature induced by 434 MHz microwave hyperthermia.

OBJECTIVE: To investigate the changes in temperature of human muscle during microwave hyperthermia. METHODS: Skin surface and muscle temperatures were measured in 11 healthy adult men (mean (SD) age 24.3 (2.2) years; height 174.2 (6.1) cm; weight 70.0 (5.3) kg) during a 30 min exposure of the thigh to 434 MHz microwave hyperthermia. Skin temperature was maintained at the pilot temperature of 40 degrees C, and the temperature of the water in the bolus was 38 degrees C. The peak power output was set at 60 W and controlled automatically to maintain the pilot temperature. The temperature was measured in the vastus lateralis muscle at an average muscle depth of 2.0 (0.2) cm, using a 23 G Teflon-shielded thermocouple. Biopsy specimens were obtained for light microscopy from three subjects. A muscle-equivalent phantom was used to evaluate the vertical heating pattern. RESULTS: Both skin and muscle temperatures increased from baseline, and muscle temperature was higher than skin temperature (skin temperature 39.2 (0.5) degrees C, temperature rise 5.0 (1.5) degrees C; muscle temperature 43.7 (0.8) degrees C, temperature rise 8.9 (1.4) degrees C). At the end of the hyperthermia treatment, muscle temperature decreased to 39.8 (0.9) degrees C, but was still 4.8 (1.5) degrees C higher than the baseline. No signs of muscle damage were observed on the basis of the blood creatine kinase activity and histological sections. CONCLUSIONS: The results show that the 434 MHz microwave hyperthermia treatment increased and maintained muscle temperature locally by 6.3-11.4 degrees C without muscle damage. These findings suggest that the microwave hyperthermia system provides effective and safe treatment.