Use of high-intensity focused ultrasound to control bleeding.
(1/604)
OBJECTIVE: High-intensity focused ultrasound (HIFU) has been shown to be effective in controlling hemorrhage from punctures in blood vessels. The objective of the current study was to investigate the capability of HIFU to stop bleeding after a more severe type of vascular injury, namely longitudinal incisions of arteries and veins. METHODS: The superficial femoral arteries, common femoral arteries, carotid arteries, and jugular veins of four anesthetized pigs were exposed surgically. A longitudinal incision, 2 to 8 mm in length, was produced in the vessel. HIFU treatment was applied within 5 seconds of the onset of the bleeding. The HIFU probe consisted of a high-power, 3.5-MHz, piezoelectric transducer with an ellipsoidal focal spot that was 1 mm in cross section and 9 mm in axial dimension. The entire incision area was scanned with the HIFU beam at a rate of 15 to 25 times/second and a linear displacement of 5 to 10 mm. A total of 76 incisions and HIFU treatments were performed. RESULTS: Control of bleeding (major hemosatsis) was achieved in all 76 treatments, with complete hemostasis achieved in 69 treatments (91%). The average treatment times of major and complete hemostasis were 17 and 25 seconds, respectively. After the treatment, 74% of the vessels in which complete hemostasis was achieved were patent with distal blood flow and 26% were occluded. The HIFU-treated vessels showed a consistent coagulation of the adventitia surrounding the vessels, with a remarkably localized injury to the vessel wall. Extensive fibrin deposition at the treatment site was observed. CONCLUSION: HIFU may provide a useful method of achieving hemostasis for arteries and veins in a variety of clinical applications. (+info)
Experimental and clinical evaluation of the harmonic scalpel in thoracic surgery.
(2/604)
The Harmonic Scalpel is an ultrasonic instrument for cutting and coagulating tissue. We are reporting our evaluation of the Harmonic Scalpel safety and efficacy in both experimental and clinical thoracic surgery. First, we confirmed the safety in thoracic surgery by following two preliminary studies using the Harmonic Scalpel. 1: Pulmonary parenchyma was incised using "Coagulating Shears" to evaluate hemostasis and air leakage. 2: Pulmonary hilar vessels were contacted directly with "Dissecting Hook" blade at optimum cutting power mode to evaluate potential vascular wall injury by the Harmonic Scalpel. Subsequently, the Harmonic Scalpel was used for a partial lung resection due to metastatic lung cancer. Particular application was for a chest wall incision, interlobar separation of the lung, and dissection of a pulmonary artery, in lung cancer operations. We concluded that cutting and hemostasis of pulmonary parenchyma could be achieved with minimal tissue damage using the Harmonic Scalpel. Compared to electric coagulation, the Harmonic Scalpel minimizes tissue charring and dissection, and eliminates thermal injury in thoracic surgery. (+info)
Ultrasound therapy for calcific tendinitis of the shoulder.
(3/604)
BACKGROUND AND METHODS: Although ultrasound therapy is used to treat calcific tendinitis of the shoulder, its efficacy has not been rigorously evaluated. We conducted a randomized, double-blind comparison of ultrasonography and sham insonation in patients with symptomatic calcific tendinitis verified by radiography. Patients were assigned to receive 24 15-minute sessions of either pulsed ultrasound (frequency, 0.89 MHz; intensity, 2.5 W per square centimeter; pulsed mode, 1:4) or an indistinguishable sham treatment to the area over the calcification. The first 15 treatments were given daily (five times per week), and the remainder were given three times a week for three weeks. Randomization was conducted according to shoulders rather than patients, so a patient with bilateral tendinitis might receive either or both therapies. RESULTS: We enrolled 63 consecutive patients (70 shoulders). Fifty-four patients (61 shoulders) completed the study. There were 32 shoulders in the ultrasound-treatment group and 29 in the sham-treatment group. After six weeks of treatment, calcium deposits had resolved in six shoulders (19 percent) in the ultrasound-treatment group and decreased by at least 50 percent in nine shoulders (28 percent), as compared with respective values of zero and three (10 percent) in the sham-treatment group (P=0.003). At the nine-month follow-up visit, calcium deposits had resolved in 13 shoulders (42 percent) in the ultrasound-treatment group and improved in 7 shoulders (23 percent), as compared with respective values of 2 (8 percent) and 3 (12 percent) in the sham-treatment group (P=0.002). At the end of treatment, patients who had received ultrasound treatment had greater decreases in pain and greater improvements in the quality of life than those who had received sham treatment; at nine months, the differences between the groups were no longer significant. CONCLUSIONS: In patients with symptomatic calcific tendinitis of the shoulder, ultrasound treatment helps resolve calcifications and is associated with short-term clinical improvement. (+info)
Effect of externally applied focused acoustic energy on clot disruption in vitro.
(4/604)
Application of low-frequency ultrasound for clot disruption has been suggested as a potential therapy to enhance thrombus dissolution, but the optimal mode for delivery of ultrasound with clot-disruptive properties has not yet been extensively explored. Target-specific effects are desirable and may be accomplished by focusing the ultrasound. Adequate focusing, however, requires a short wavelength. The aim of this study was to compare the clot-disruptive effects of different modalities of focused acoustic energy. An in vitro model (10 blood clots for each modality) was used to test the clot-disruptive capacity of (i) shock waves generated in an electrohydraulic lithotriptor; (ii) focused continuous ultrasound of frequency 1.1 MHz, delivered from a specially constructed piezoelectric transducer; and (iii) focused pulse-modulated ultrasound of frequency 1.1 MHz delivered from the same transducer. Exposure to 30 s of focused pulse-modulated ultrasound caused a marked reduction (99+/-2%) in clot weight compared with 30 shock waves (11+/-5%) or 30 s exposure to focused continuous wave ultrasound (11+/-6%) (P<0.0001). The observed marked and rapid disruptive effect on blood clots of focused high-frequency ultrasound indicates an alternative approach for external ultrasound-mediated thrombus destruction in vivo. The focused pulse-modulated technique has potential to exhibit the desired effect in a well-defined target volume and provides the means for control of the average power. (+info)
Histological observations and the process of ultrasound contrast agent enhancement of tissue plasminogen activator thrombolysis with ultrasound exposure.
(5/604)
Although the enhancement of tissue plasminogen activator (tPA) induced thrombolysis by ultrasound has been reported to be augmented by ultrasound contrast agents (UCA), few data exist regarding its process. The present study evaluated the effect of a galactose based UCA on the efficacy of ultrasonic enhancement of tPA thrombolysis and observed the serial changes in the acoustic property and histopathology. A catheter-type transducer capable of ultrasound emission in both continuous (CW) and pulsed wave (PW) was used. The tPA thrombolysis was studied in 30 artificial white thrombi, which were assigned to 4 study groups based on insonation modes and with and without UCA. Each sample was suspended in 100ml saline in a beaker. Five minutes after tPA (8000U) administration, ultrasound was applied for 10min. For the UCA-treated groups, UCA (0.25g) was added 5 min after the start of ultrasound exposure. The alteration of the thrombus was monitored with echography. Weight reduction of the thrombus was -25+/-6% in PW and -30+/-7% in CW, which was significantly enhanced by UCA treatment, 40+/-3% (p<0.005) in PW+UCA and -43+/-7% (p<0.005) in CW+UCA. The area of thrombus echo image minimally decreased with ultrasound alone (-12+/-6%: PW, -23+/-11%: CW). In the UCA groups, UCA induced a remarkable reduction of size (-36+/-3%: PW+UCA, -43+/-7%: CW+UCA) with a high-echo intensity in the superficial layer of the thrombus, where multiple cavity formation was observed by light microscope. UCA markedly enhanced the effect of ultrasound on tPA thrombolysis. The altered acoustic property and corresponding histological microcavity formation in the shallow layer within the thrombus suggests that UCA augmented infiltration of tPA into the thrombus. (+info)
No effect of bipolar interferential electrotherapy and pulsed ultrasound for soft tissue shoulder disorders: a randomised controlled trial.
(6/604)
OBJECTIVE: To assess the efficacy of bipolar interferential electrotherapy (ET) and pulsed ultrasound (US) as adjuvants to exercise therapy for soft tissue shoulder disorders (SD). METHODS: Randomised placebo controlled trial with a two by two factorial design plus an additional control group in 17 primary care physiotherapy practices in the south of the Netherlands. Patients with shoulder pain and/or restricted shoulder mobility, because of a soft tissue impairment without underlying specific or generalised condition, were enrolled if they had not recovered after six sessions of exercise therapy in two weeks. They were randomised to receive (1) active ET plus active US; (2) active ET plus dummy US; (3) dummy ET plus active US; (4) dummy ET plus dummy US; or (5) no adjuvants. Additionally, they received a maximum of 12 sessions of exercise therapy in six weeks. Measurements at baseline, 6 weeks and 3, 6, 9, and 12 months later were blinded for treatment. OUTCOME MEASURES: recovery, functional status, chief complaint, pain, clinical status, and range of motion. RESULTS: After written informed consent 180 patients were randomised: both the active treatments were given to 73 patients, both the dummy treatments to 72 patients, and 35 patients received no adjuvants. Prognosis of groups appeared similar at baseline. Blinding was successfully maintained. At six weeks seven patients (20%) without adjuvants reported very large improvement (including complete recovery), 17 (23%) and 16 (22%) with active and dummy ET, and 19 (26%) and 14 (19%) with active and dummy US. These proportions increased to about 40% at three months, but remained virtually stable thereafter. Up to 12 months follow up the 95% CI for differences between groups for all outcomes include zero. CONCLUSION: Neither ET nor US prove to be effective as adjuvants to exercise therapy for soft tissue SD. (+info)
Acceleration of increase in bone mineral content by low-intensity ultrasound energy in leg lengthening.
(7/604)
The effect of ultrasound energy on bone has been studied for a long time. In particular, multiple effects of low-intensity ultrasound energy have recently been demonstrated experimentally, such as increases in bending strength of fracture callus, acceleration of soft callus formation and endochondral ossification of the callus at the fracture site, stimulation of aggrecan gene expression, or modulation of TGF-beta synthesis and increase of calcium uptake. Clinically, prospective, randomized, and double-blind trials showed the efficacy of low-intensity ultrasound beam stimulation in the acceleration of fracture healing, with a significant decrease in the time to healing. On the other hand, callotasis, a popular method for bone lengthening, requires much time for new bone formation, and an external fixator must be remain on the patient for a long period. This is one of the major problems of the callotasis technique. If ultrasound energy stimulation could accelerate the rate of callus formation in callotasis, the external fixator could be removed earlier, the treatment period could be shortened, and the patient could return to daily activities more quickly. We report on the use low-intensity ultrasound beam stimulation during leg lengthening with the callotasis method in which callus formation was poor. (+info)
Shock-wave therapy is effective for chronic calcifying tendinitis of the shoulder.
(8/604)
We report a prospective study of the effects of extracorporeal shock-wave therapy in 195 patients with chronic calcifying tendinitis. In part A 80 patients with chronic symptoms were randomly assigned to a control and three subgroups which had different treatment by low-energy and high-energy shock waves. In part B 115 patients had either one or two high-energy sessions. We recorded subjective, functional and radiological findings at six months after treatment. The results showed energy-dependent success, with relief of pain ranging from 5% in our control group up to 58% after two high-energy sessions. The Constant scores and the radiological disintegration of calcification were also dose-dependent. Shockwave therapy should be considered for chronic pain due to calcific tendinitis which is resistant to conservative treatment. (+info)