Effects of energy-matched pulsed and continuous ultrasound on tumor growth in mice.

BACKGROUND AND PURPOSE: A diagnosis of cancer is a contraindication for the use of therapeutic ultrasound (US). Continuous US applied to murine tumors has resulted in larger and heavier tumors compared with controls. We compared tumor growth using low-power continuous US and energy-matched pulsed US. SUBJECTS: Female C57BL/6 mice (N = 174) were used. METHODS: Animals received subcutaneous injections of methylcholanthrene tumor cells. The mice were randomly divided into three groups: 60 mice that received low-power continuous US for 5 minutes at 0.75 W/cm2 (LC US group), 63 mice that received pulsed US for 12.5 minutes at 1.5 W/cm2 (pulsed US group), and 51 mice that served as a control group. The LC and pulsed US groups received equal US energy. Both experimental groups received 10 treatments of 3-MHz US, which was applied directly over the tumor. The control group received identical handling but no US. After treatment, the tumors were excised, weighed, and measured. A one-way analysis of variance, followed by Newman-Keuls post hoc testing, was used to analyze the data. RESULTS: Mean tumor weights (in grams) and volumes (in cubic millimeters) were 0.563 g and 564 mm3 for the LC US group, 0.560 g and 525 mm3 for the pulsed US group, and 0.516 g and 406 mm3 for the control group. CONCLUSION AND DISCUSSION: Reducing total US energy will result in less growth of murine tumors. When infusing equal energy, continuous and pulsed US will produce similar effects on tumor growth.

Effects of continuous therapeutic ultrasound on growth and metastasis of subcutaneous murine tumors.

BACKGROUND AND PURPOSE: The use of therapeutic ultrasound (US) in the presence of malignant neoplasms has been contraindicated in physical therapy practice despite a lack of convincing scientific evidence. Some studies have shown that high levels of US, which increase tissue temperatures greater than 42 degrees C, can kill tumors. We sought to determine whether the application of continuous therapeutic US would alter the growth or metastasis of methylcholanthrene-induced solid tumors in mice. SUBJECTS: Seventy-one female C57BL/6 mice, age 6 to 8 weeks, received subcutaneous injections of 5 x 10(5) tumor cells. METHODS: When tumors grew to 0.5 cm in diameter, the mice were randomly assigned to either a control group (n = 34) or an experimental group (n = 37). The experimental group received 10 treatments over a 2-week period of 3-MHz continuous US at 1.0 W/cm2 for 5 minutes, using a 0.5-cm2 sound head directly over the tumor. The control group received the same handling except for the US treatment. Tumor dimensions were measured on days 1 (baseline), 7 (midtreatment), and 14 (preexcision and postexcision). Tumors were weighed after excision, and the mice were evaluated by necropsy and histopathology of regional lymph nodes. RESULTS: All tumors grew larger over time, but final tumor volume and weight were larger in the experimental group (789 mm3 and 0.932 g) than in the control group (395 mm3 and 0.506 g). No significant difference existed in the number of metastatic lymph nodes between groups. CONCLUSION AND DISCUSSION: Continuous therapeutic US increased the volume and weight of subcutaneous murine tumors in mice. We urge caution in the use of continuous therapeutic US in the areas of tumors or suspected tumors.

Treatment of large subchondral tumors of the knee with cryosurgery and composite reconstruction.

The radiographic and clinical outcomes of 9 patients with large benign aggressive or low-grade malignant periarticular tumors of the knee who were treated with cryosurgery and composite reconstruction (cementation, bone graft, and internal fixation) in lieu of primary resection were analyzed. The minimum followup was 2 years (range, 24-103 months). There were 6 giant cell tumors and a single case each of chondroblastoma, chondrosarcoma, and fibrosarcoma in the study group. Six lesions involved the distal femur and 3 the proximal tibia. Functional outcomes were graded according to the Enneking Modified System for the Functional Evaluation of Tumor and The Knee Rating Scale of The Hospital for Special Surgery. All lesions extended to within 2 mm of the articular surface. Local tumor control was achieved in 8 patients (89%). The single local recurrence was successfully managed with repeat curettage, cryosurgery, cementation, and internal fixation. All 9 patients had excellent functional outcomes according to both evaluation scales.

Evaluation of iontophoretically applied dexamethasone for painful pathologic temporomandibular joints.

The effects of iontophoretically applied dexamethasone in a lidocaine vehicle were compared with those of saline placebo in 53 patients with one of three diagnoses of painful temporomandibular joint pathologic conditions: disk displacement with reduction, disk displacement without reduction, and osteoarthritis. Both dexamethasone and the saline placebo produced a significant reduction in pain scores from baseline levels after the first two of three treatments. There were no observed differences, however, in pain report or mandibular range of motion between the dexamethasone and placebo groups. A trend for pain relief was noted in the subgroup that received dexamethasone with a diagnosis of osteoarthritis. Results may reflect varying degrees of inflammation or central nervous system hyperexcitability, or both, in this heterogeneous study sample. Potential confounding variables were lack of knowledge of actual drug penetration, the effects of electric current transmitted by the iontophoresor, and pain reduction caused by cyclic fluctuations in symptoms. These data suggest that iontophoretically applied dexamethasone is no more effective than saline placebo in providing pain relief in patients with temporomandibular joint pain.