A new closed-loop cryosurgical device for endometrial ablation.

A new cryosurgical device was developed in an attempt to overcome problems of current systems. It incorporates a mixed-fluid J-T stage, thereby reducing working pressure. This allows incorporation of an oil-free compressor to circulate the mixture and eliminates the need for coolant replenishment. The compressor console is small and portable, with a footprint of 3.5 square feet. Probe surface temperatures of -90 to -110 inverted exclamation mark C are achieved. Working pressures are reduced 3- to 10-fold over existing devices (300-350 p.s.i.). In a live goat study, liver ice balls 3.7 cm in diameter were created in 10 minutes. In an extirpated uterus, in a 37 inverted exclamation mark C water bath, tissue ice balls ranging from 29.1 to 35.4 mm were created in 6 minutes and tissue was destroyed to depths of 6 to 12 mm. This cryosurgical system is suitable for endometrial ablation.

Endometrial cryoablation with ultrasound visualization in women undergoing hysterectomy.

STUDY OBJECTIVES: To evaluate tissue effects of cryosurgical endometrial ablation in women just before hysterectomy, characterize ultrasound monitoring of freezing, determine the feasibility of a new probe-angling procedure, and assess the safety profile by monitoring serosal surface temperatures. DESIGN: Single arm safety study enrolling ten women at two centers (Canadian Task Force classification II-2). SETTING: Two clinical sites. Patients. Ten women scheduled for hysterectomy. INTERVENTION: Hysterectomy with a new cryosurgical device (First Option, CryoGen, Inc., San Diego, CA) that achieves surface temperatures below -90 inverted exclamation mark C to freeze endometrium. MEASUREMENTS AND MAIN RESULTS: The freeze protocol involved angling the probe toward each cornu. Maximum ice front diameter at the end of the first angled freeze ranged from 24 to 34 mm, and maximum ice ball diameter at the end of the second freeze ranged from 28 to 37 mm. The margin between the advancing ice front and serosal surface was monitored by ultrasound. In all cases the margin was safe and no reduction in serosal surface temperatures occurred. Depth of necrosis ranged from 9 to 12 mm as determined by tetrazolium staining and electron microscopy, and there was no full-thickness myometrial destruction. Total endometrial destruction was achieved. CONCLUSION: Cryosurgical ablation of the endometrium with the First Option system with angled freezes and ultrasound monitoring appears to be feasible and safe given our preliminary data.

Extirpated uterine endometrial cryoablation with ultrasound visualization.

STUDY OBJECTIVE: To determine the efficacy of cryoablation of the uterus monitored by ultrasound. DESIGN: Observational research (Canadian Task Force classification II-2). SETTING: Clinic laboratory. SUBJECTS: Eight uteri obtained after hysterectomy. INTERVENTION: The uteri were subjected to freeze and thaw cycles in a 37 inverted exclamation markC water bath. Ultrasound was used to monitor the advancing ice front and ice ball diameter. MEASUREMENTS AND MAIN RESULTS: Specimens were sectioned and stained with tetrazolium red to determine the region of nonviable tissue. The maximum average ice ball diameter as measured by ultrasound was 33.2 mm (range 29.1-35.4 mm). The average maximum diameter of nonviable tissue region was 24 mm (range 21.4-28.4 mm), with depth of tissue destruction ranging from 6 to 12 mm. CONCLUSION: Cryosurgery at temperatures below -90 inverted exclamation mark C achieves excellent destruction of uterine tissue and complete destruction of endometrium. Ultrasound can be used to monitor freezing.

Randomized, double-blind comparison of transdermal clonidine with oral propranolol.

The antihypertensive effect of transdermal clonidine (TC) vs. oral propranolol (OP) was evaluated in 32 patients with mild essential hypertension (mean BP 150/95 mm Hg). The protocol consisted of a 4-week pretreatment washout period, a 2- to 6-week titration, a 4-week maintenance phase, and a 1-week postwashout phase. BP control (diastolic BP less than 90 mm Hg) was achieved in 15 out of 17 transdermal patients, and in 12 out of 14 propranolol subjects. Comparable decreases in systolic/diastolic BP were noted (-19/15 mm Hg for TC vs. -24/13 mm Hg for OP). No rebound symptoms were reported after sudden cessation of the transdermal system during the post-treatment washout. Side effects were recorded in 3 out of 17 TC patients, and in 3 out of 15 OP patients with 1 OP dropout. A mild transient erythematous rash developed in 2 TC and 2 OP (placebo patch) patients. We conclude that the safety and efficacy of TC is comparable to OP for monotherapy in mild hypertensives.