Fibrous muscular contractures: treatment with a new direct contact microwave applicator operating at 915 MHz.

A patient having bilateral contractures of the rectus femoris and brachial biceps muscles due to pentazocine injection was treated with a regime of heat and stretch. Heat was provided by a new air cooled direct contact applicator operating at 915 MHz. Stretch was applied by adding weights to a cable which was attached to the arm or leg to be stretched. While the left and right elbows which were limited by the contracted biceps were not stretched sufficiently to achieve a normal range of motion, the rectus femoris muscle on both sides did achieve a normal range of motion.

Temperatures in human thighs after hot pack treatment followed by ultrasound.

Temperature distributions were measured in the anterior thigh of human volunteers after preheating with a hot pack followed by ultrasound, a frequently used therapeutic procedure. The skin surface temperature is elevated by this procedure but the highest temperature is still produced at the bone-muscle interface at the end of the treatment session.

Knee lock device for knee ankle orthoses for spinal cord injured patients: an evaluation.

The effect of a specially designed knee lock in a knee ankle orthosis was studied in 2 able-bodied volunteers and in 2 patients with spinal cord lesions. This lock allows the knee to bend during the swing phase but locks the knee securely during the stance phase. The device is intended to improve gait pattern and reduce oxygen consumption more than a standard knee lock which keeps the knee straight throughout the entire gait cycle. Energy savings with the knee locking mechanism were significant only at ambulation rates at or above 73 meters/min, a speed which could only be attained by able-bodied subjects. To achieve such high rates of ambulation a patient's hip flexors must be strong; yet a knee ankle orthosis is required only when the patient's knee extensors are weak. In patients with spinal cord injuries, this pattern of muscle strength is rarely encountered. The innervation of hip flexors or knee extensors overlaps, so voluntary control of these muscles will either be present or absent for both muscle groups. Therefore, most spinal cord injured persons who need a knee orthosis would not greatly benefit from this locking mechanism. There may be other conditions in which this device will prove valuable.

Pneumatic and standard double upright orthoses: comparison of their biomechanical function in three patients with spinal cord injuries.

A detailed analysis of the biomechanical and physiological function of pneumatic orthoses comparing them to the standard double upright knee ankle orthoses was performed in three patients with different lesion levels. The results suggest that the main value of the long pneumatic orthosis is for early mobilization of the patient. In addition, the long pneumatic orthosis provides hip and trunk stabilization for marginal walkers who walk for exercise purposes. It is likely that most long-term functional ambulators will choose the standard knee ankle orthosis (KAO). The study dose not represent a statistical sample; therefore generalization must be limited.

Heating patterns produced in humans by 433.92 MHz round field applicator and 915MHz contact applicator.

Temperature distributions produced by a round field applicator operating at a frequency of 433.92 megahertz (MHz) are comparable to those produced by a 915 MHz cooled contact applicator in human volunteers with less than or equal to 1 cm or greater than or equal to 2 cm of subcutaneous fat. The major difference between the two applicators is the temperatures produced on the skin surface and in the subcutaneous fat in humans. The circulating coolant of the 915 MHz contact applicator keeps skin surface temperatures much lower than those produced by the round field applicator in thick and thin subjects. It also tends to cool the superficial subcutaneous fat layer in thin subjects but doesn't affect the deeper subcutaneous fat layer in subjects with greater than or equal to 2 cm of subcutaneous fat. The 915 MHz contact applicator gives the ability to control by cooling the temperatures produced in the superifical tissues. By regulating the temperature of coolant and time of cooling, temperature gradients can be modified so the highest temperatures may be found in the muscle. However, the superficial tissue temperature cannot be regulated with the present application of the 433.92 MHz applicator. When the two applicators were compared, it was shown that the 433.92 MHz round field applicator did not surpass the heating ability of the 915 MHz contact applicator. Therefore, at this time, there is no reason to legalize the frequency of 433.92 MHz for diathermy use in the United States.

Temperature distribution produced in models by three microwave applicators at 433.92 megahertz.

Temperature distributions produced in phantom models by diathermy applicators operating at a frequency of 433.92 MHz, a frequency not approved for diathermy by Federal Communication Commission regulations, and an experimental cooled contact applicator operating at an assigned frequency of 915 MHz were compared. The specially designed direct contact applicator with surface cooling elevated deep muscle temperatures as effectively as the "Rundfeldstrahler" operating at the lower frequency in spite of the better penetration of the energy at the lower frequency. The "Pyrodor" and the "Langfeldstrahler," the largest of the applicators operating at 433.92 MHz, do not appear to offer any advantage over existing diathermy equipment. The highest temperatures produced with these applicators were at the fat-muscle-interface.