A reappraisal of cryosurgery for eyelid basal cell carcinomas. (25/518)

BACKGROUND/AIMS: Liquid nitrogen spray freezing has been successfully applied for basal cell carcinomas in the eyelid region, but is not yet in general use. The reasons for this were analysed and the development of a more reliable, safer cryosurgical technique aimed for. METHODS: New cryosurgical apparatus, contact probes with increased freezing power, and a special application technique were developed and clinically tested in a consecutive series of 221 patients with primary basal cell carcinomas of the lid region. Special efforts yielded follow up reports of 220 out of the 221 patients. RESULTS: Experimental measurements and clinical results demonstrated that this cryosurgical technique was at least as effective as spray freezing, with lower risks. The rate of recurrent tumours in patients followed up for 5 years or longer was 5.1% (surgeons first result) respectively 0.6% (result after optimised second cryosurgery). The figures were 6.8%, respectively max 2.7%, when including all patients, independent of follow up time. CONCLUSION: Traditional surgery and histopathology, still used at numerous places, resulted in higher recurrence rates despite extended loss of healthy eyelid tissues and should be abandoned. Micrographic surgery is considered mandatory to save more of the healthy structures and to obtain lower recurrence rates. Cost and time require worldwide restriction of micrographic surgery to selected cases. Updated cryosurgery provides a low cost option to micrographic surgery and results in preservation of eyelid structures and lacrimal pathways, tarsal plate, lid margin. It provides excellent cosmetic results. Thus, primary basal cell carcinomas in the eyelid region of suitable size and location should receive updated cryosurgery, and tumours beyond its range micrographic surgery.  (+info)

Ablative therapy for liver tumours. (26/518)

Established ablative therapies for the treatment of primary and secondary liver tumours, including percutaneous ethanol injection, cryotherapy, and radiofrequency ablation, are discussed. Newer techniques such as magnetic resonance imaging guided laser interstitial thermal therapy of liver tumours has produced a median survival rate of 40.8 months after treatment. The merits of this newly emerging technique are discussed, together with future developments, such as focused ultrasound therapy, which holds the promise of non-invasive thermoablation treatment on an outpatient basis.  (+info)

Preliminary experience with cryoablation of renal lesions smaller than 4 centimeters. (27/518)

Nephron-sparing surgical techniques represent an attractive treatment approach for small renal lesions that are limited only by potential operative morbidity. This study tests the hypothesis that an alternative strategy of in situ cryoablation of these lesions may further reduce the incidence of complications with similar efficacy. Beginning August 1996,17 patients were enrolled in an institutional review board-approved protocol for open renal cryoablation for lesions smaller than 4 cm in diameter. The median age was 62 years (range, 35-75 years). The median preoperative lesion size was 2.0 cm (range, 1.1-4.2 cm) determined with either computed tomography or magnetic resonance imaging. A double freeze-thaw technique to -180 degrees C was used under direct intraoperative ultrasound monitoring. The median length of follow-up was 30 months (range, 10-60 months), with 8 patients followed up for more than 20 months. The procedure was accomplished in 3 hours (range, 2.25-4.25 hours) through a 5-cm to 7-cm subcostal incision. The median blood loss was 100 mL, and the median hospital stay was 2 days (range, 2-8 days). The median intraoperative lesion was 2.4 cm, which was not statistically different from preoperative measurements. Postoperative serum creatinine levels were unchanged except for a transient increase from 5.5 mg/dL to 7.0 mg/dL in one patient. Follow-up magnetic resonance imaging scans have demonstrated infarction and a reduction of lesion size in 15 of 16 cases. The size of one patient's mass was unchanged after 3 months. Renal cryoablation via an open approach is associated with few complications and represents a viable alternative to extirpative surgical techniques. The open exposure provides an accurate assessment of the renal unit with definitive ultrasound visualization.  (+info)

Quantitative assessment of the integrity of the blood-retinal barrier in mice. (28/518)

PURPOSE: The purpose of this study was to develop and characterize a quantitative assay of blood-retinal barrier (BRB) function in mice and to determine the effect of several purported vasopermeability factors on the BRB. METHODS: Adult C57BL/6J mice were treated with three regimens of increasingly extensive retinal cryopexy and subsequently were given an intraperitoneal injection of 1 microCi/g body weight of [(3)H]mannitol. At several time points, the amount of radioactivity per milligram tissue was compared in retina, lung, and kidney. Time points that maximize signal-to-background differential in the retina were identified, and the ratio of counts per minute (CPM) per milligram retina to CPM per milligram lung (retina-to-lung leakage ratio, RLLR) or kidney (retina-to-renal leakage ratio, RRLR) were calculated. This technique was then used to compare the amount of BRB breakdown that occurs after intravitreous injection of vascular endothelial growth factor (VEGF), insulin-like growth factor (IGF)-1, prostaglandin (PG) E(1), PGE(2), interleukin (IL)-1beta, or tumor necrosis factor (TNF)-alpha. RESULTS: Twenty-four hours after retinal cryopexy, there was a higher level of radioactivity in treated than in control retinas, and the signal-to-background difference was optimal when measurements were obtained 1 hour after injection of [(3)H]mannitol. In untreated mice, the RLLR was 0.30 +/- 0.02 and the RRLR was 0.22 +/- 0.01. Twenty-four hours after one 5-second application of retinal cryopexy, the RLLR was 0.73 +/- 0.20 and the RRLR was 0.71 +/- 0.23. With increasing amounts of cryopexy, there was an increase in the RLLR and RRLR, so that after two 10-second applications, the RLLR was 1.66 +/- 0.31 and the RRLR was 1.47 +/- 0.20. Intravitreous injection of VEGF, IGF-1, PGE(1), PGE(2), IL-1beta, or TNF-alpha each caused significant increases in the RLLR and RRLR, but there were some differences in potency and time course. VEGF caused prominent BRB breakdown at 6 hours that returned to near normal by 24 hours. IL-1beta also caused relatively rapid breakdown of the BRB, but its effect was more prolonged than that caused by VEGF. There was delayed, but substantial breakdown of the BRB after injection of TNF-alpha. IGF-1, PGE(2), and PGE(1) caused less severe, relatively delayed, and more prolonged BRB breakdown. CONCLUSIONS: Measurement of the RLLR or RRLR after intraperitoneal injection of [(3)H]mannitol in mice provides a quantitative assessment of BRB function that is normalized and can therefore be compared from assay to assay. Comparison of the extent and duration of BRB breakdown after intravitreous injection of vasoactive substances shows that agents can be grouped by resultant extent and time course of leakage. Additional studies are needed to determine whether this grouping has its basis in shared mechanisms of BRB disruption.  (+info)

Comparison of anatomic isthmus block with the modified right atrial maze procedure for late atrial tachycardia in Fontan patients. (29/518)

BACKGROUND: Late atrial reentry tachycardia (AT) after Fontan repair is common, with limited efficacy of medical therapy in preventing AT recurrence. In this study, two approaches to surgical arrhythmia ablation in patients with refractory AT undergoing Fontan revision are compared: cryoablation of the inferomedial right atrium (RA), and a more extensive modified RA maze procedure designed to eliminate all potential RA reentrant circuits. METHODS AND RESULTS: Fontan revision was performed in 23 patients with AT, using inferomedial RA cryoablation (Group 1, n=8) and modified RA maze procedure (Group 2, n=15). There was no difference in age at initial Fontan, age at Fontan revision, age at onset of AT, or number of failed antiarrhythmic medications. Patients underwent preoperative, intraoperative, and postoperative electrophysiological studies. Thirty-eight different tachycardia circuits were induced in preoperative studies with 3 major areas of RA involvement: the lower lateral RA, the atrial septum, and the inferomedial RA. At postoperative electrophysiological study, AT was inducible in 62% of Group 1 patients but only 7% of Group 2 patients (P<0.02). With mean follow-up of 43 months, 5 of 8 patients in Group 1 experienced AT recurrence compared with none in Group 2 (P<0.001). There was no significant difference in length of hospital stay or complication rate comparing the two groups. CONCLUSION: Modified RA maze procedure is superior to anatomic isthmus block in treating reentrant AT in postoperative Fontan patients. The modified RA maze has eliminated AT recurrence at mid-term follow-up with low morbidity and mortality.  (+info)

Cytosolic Ca2+ triggers early afterdepolarizations and Torsade de Pointes in rabbit hearts with type 2 long QT syndrome. (30/518)

The role of intracellular Ca2+ (Ca2+i) in triggering early afterdepolarizations (EADs), the origins of EADs and the mechanisms underlying Torsade de Pointes (TdP) were investigated in a model of long QT syndrome (Type 2). Perfused rabbit hearts were stained with RH327 and Rhod-2/AM to simultaneously map membrane potential (V(m)) and Ca2+i with two photodiode arrays. The I(Kr) blocker E4031 (0.5 microM) together with 50 % reduction of [K+]o and [Mg2+]o elicited long action potentials (APs), V(m) oscillations on AP plateaux (EADs) then ventricular tachycardia (VT). Cryoablation of both ventricular chambers eliminated Purkinje fibres as sources of EADs. E4031 prolonged APs (0.28 to 2.3 s), reversed repolarization sequences (baseapex) and enhanced repolarization gradients (30 to 230 ms, n = 12) indicating a heterogeneous distribution of I(Kr). At low [K+]o and [Mg2+]o, E4031 elicited spontaneous Ca2+iand V(m) spikes or EADs (3.5 +/- 1.9 Hz) during the AP plateau (n = 6). EADs fired 'out-of-phase' from several sites, propagated, collided then evolved to TdP. Phase maps (Ca2+ivs. V(m)) had counterclockwise trajectories shaped like a 'boomerang' during an AP and like ellipses during EADs, with V(m) preceding Ca2+iby 9.2 +/- 1.4 (n = 6) and 7.2 +/- 0.6 ms (n = 5/6), respectively. After cryoablation, EADs from surviving epicardium (~1 mm) fired at the same frequency (3.4 +/- 0.35 Hz, n = 6) as controls. At the origins of EADs, Ca2+ipreceded V(m) and phase maps traced clockwise ellipses. Away from EAD origins, V(m) coincided with or preceded Ca2+i. In conclusion, overload elicits EADs originating from either ventricular or Purkinje fibres and 'out-of-phase' EAD activity from multiple sites generates TdP, evident in pseudo-ECGs.  (+info)

The effect of cryo-maze procedure on early and intermediate term outcome in mitral valve disease: case matched study. (31/518)

BACKGROUND: The maze procedure is an effective way to treat atrial fibrillation (AF) associated with mitral valve disease. In a last several years, cryoablation was substituted for atrial incision in many reports to simplify the maze procedure. However, there has been no comparative study to delineate the feasibility of the use of cryoablation. METHODS AND RESULTS: We compared the early and intermediate-term results of the maze procedure including pulmonary venous isolation from the left atrium using cryoablation (CM) with our conventional (Kosakai) maze procedure (KM) including encircling incision around the orifices of pulmonary veins. One hundred and 10 pairs of patients were matched in the age, left atrial dimension >70 mm, duration of AF >0 years, previous cardiac surgery, mechanical valve implantation and concomitant aortic valve procedures. CM required significantly shorter cardiopulmonary bypass time (186+/-56 minute versus 214+/-47 minute, P=0.001) and aortic cross-clamp time (134+/-43 minute versus 144+/-37 minute, P=0.03) than KM with less chest tube drainage (590+/-353 mL versus 745+/-618 mL, P=0.02) for 12 hours after operation. The sinus rhythm restoration rate in CM group (85.4%) was comparable with KM group (86.4%) at discharge. In the late results, the actuarial freedom from recurrence of sustained AF at 3 years in CM group (97.7%) was not significantly (P=0.11) different from that in KM group (90.4%). The actuarial freedom from stroke at 3 years in CM group was 99.0%. CONCLUSION: The modification of the maze procedure including cryoablation for pulmonary venous isolation provided less aortic cross-clamp time and less amount of chest tube drainage with the comparable recovery and maintenance of sinus rhythm with KM. CM is a reliable and less invasive surgical option for the AF associated with mitral valve disease.  (+info)

Efficacy of fluorine-18-deoxyglucose positron emission tomography in detecting tumor recurrence after local ablative therapy for liver metastases: a prospective study. (32/518)

PURPOSE: The aims of this prospective study were to investigate the potential role of fluorine-18-deoxyglucose (FDG) positron emission tomography (PET) in determining the efficacy of the local tumor ablative process and to determine the added value of FDG-PET in the detection of tumor recurrence during follow-up. PATIENTS AND METHODS: Twenty-three patients with unresectable colorectal liver metastases were followed up after local ablative therapy consisting of a standard protocol including FDG-PET scanning, computed tomography (CT) scanning, and carcinoembryonic antigen measurements. The mean follow-up period was 16 months (range, 10 to 21 months). RESULTS: Ninety-six lesions was treated, 56 by local ablative treatment. Within 3 weeks after local ablative treatment, 51 lesions became photopenic on FDG-PET, while five lesions (in five patients) showed persistent activity on FDG-PET. In four of five FDG-PET-positive lesions, a local recurrence developed during follow-up; one FDG-PET-positive lesion turned out to be an abscess. None of the FDG-PET-negative lesions developed a local recurrence during a mean follow-up period of 16 months. During follow-up, 11 patients showed recurrence in the liver outside of the treated area. In all cases, previously negative FDG-PET scans became positive. Extrahepatic recurrence was encountered in nine patients during follow-up; FDG-PET showed all nine cases of tumor recurrence. There was one false-positive FDG-PET caused by an intra-abdominal abscess. In all patients, the time point of detection of recurrence by FDG-PET was considerably earlier than the detection by CT. CONCLUSION: FDG-PET seems to have a significant impact in measuring treatment efficacy directly after local ablative therapy. Furthermore, FDG-PET has an added value in patient follow-up because it reveals recurrences earlier than conventional diagnostic modalities.  (+info)