A clinical study on the removal of gingival melanin pigmentation with the CO(2) laser.

BACKGROUND AND OBJECTIVE: In a previous study, the possibility of removal of dog gingival melanin pigmentation with CO(2) laser therapy was reported. The present study was designed to investigate the effect of the CO(2) laser on human gingival pigmentation and evaluate the clinical outcome. STUDY DESIGN/MATERIALS AND METHODS: A CO(2) laser (output: 6-8 W, pulse duration: 0.2 seconds) was irradiated on the melanin pigmented gingival surface of 10 patients, aged 20-49 years. Follow-up clinical and histopathological evaluations were performed. RESULTS: The CO(2) laser was effective in removing melanin pigmentation in all patients. In the histopathological study, no pigmented-laden cells nor any inflammatory cell infiltration was observed following laser irradiation. No re-pigmentation was seen in any case in the first year. However, four of seven cases showed re-pigmentation at 24 months. The re-pigmentation was almost equal to the preoperative state. CONCLUSIONS: The CO(2) laser has proved to be another effective, safe, and easily applicable therapy for the removal of gingival melanin pigmentation.     

Cryosurgical treatment of tumors]

In 84 out of 164 carcinoma patients, admitted from June 1974 to September 1975 -- altogether 98 cryosurgical operations were performed according to the stage of the tumors. This was done as additional treatment to radical operation, as monotherapy, as additional treatment to palliative resection, or as a mono-palliative-therapy. After a discussion of the method, and a critical evaluation of the advantages and disadvantages (including new application areas) cryosurgery is proved to be superior to the conventional method in the destruction of tumor, e.g. in the liver, pancreas, roof of mesentery, and iliac region. The same is true when it is used as a palliative treatment in processes where access is difficult. On the other hand it seems that tumor-freezing shortens the life of patients, weakened through inanition.     

Cryosurgical haemorrhoidectomy.

One hundred consecutive cases of haemorrhoids were treated by cryosurgery. The cryoprobe used is a convenient and simple instrument and gave a satisfactory result in 94 of the patients. The technique and complications are described. The patients were treated as outpatients, usually without anaesthesia.     

Cryosurgical treatment of hemorrhoids in Japan

Hemorrhoid treatment in Japan consists mainly of conservative therapy and conventional surgery. Cryosurgical hemorrhoidectomy, though still not widely used, has attained a reputation for low profile surgery and relatively painless recovery compared to conventional surgery, in spite of some inevitable problems. Our series includes external hemorrhoids and prolapse, which have been ruled out from the indications for cryosurgery, yet obtained satisfactory results. A threatening drawback is lower digestive tract hemorrhage, which occurred in 19 of 372 prolapse patients (5.1%) after cryosurgery. As for its pathogenesis, an autoimmune reaction at the site of the terminal ileum is postulated. Characteristics of the hemorrhage are: onset around the 14th postoperative day at night or early in the morning, and seen particularly in nervous patients. Prophylactic administration orally of covering materials may reduce incidence. Cryosurgery is certainly an effective measure for the treatment of hemorrhoids, including prolapse.     

Cryosurgical treatment of basal cell carcinoma of the skin

Cryosurgical method was used for the treatment of 102 patients with basal cell carcinoma of the skin. A portable cryosurgical apparatus with a set of applicators was used. Liquid nitrogen was used as the cold agent. The method is simple and accessible and gives good long-term results: recidivation is not more than 2%, rough cicatricial keloids are not formed.     

Cryosurgical treatment for anorectal cancer. A method of palliative or adjunctive management

Thirty-two patients with anorectal cancer were treated with cryosurgery from April 1974 to August 1985. The purpose of the treatment was to provide palliative benefits to 27 patients. In one group (17 patients) who did have previous surgery, cryosurgery was used for the predominant symptoms of melena and/or obstruction. In the postoperative period, local bleeding was minimal, and palliation was judged significant. The survival time of this group ranged from 1 month to 18 months. In another group (10 patients) in whom recurrent cancer followed previous operative treatment, cryosurgery was used to control the local invasion and tumor bulk. All of these patients died within 17 months after recurrence was discovered. Nevertheless, treatment was judged to provide significant palliation. A small group (five patients) was treated with the intent to cure, and cryosurgical techniques were used as an adjunct to surgical excision. Four patients survived more than 8 years after the operation. Two of these patients died of illnesses other than cancer. The local destruction of an anorectal cancer by cryosurgery in these patients provided effective control of the tumor. Bleeding was controlled, and tumor bulk was reduced in size. All patients were treated without any complications caused by cryosurgery. This experience indicates that the cryosurgical technique provides therapeutic benefits for selected patients with anorectal cancer, especially those of high surgical risk.     

Cryosurgical treatment of rectal carcinoma (author's transl)]

After comprehensive experimental especially morphological studies in animals, we started cryo-therapy of rectal carcinoma in 1972. We now present the first critical 5-years review concerning indication, clinical results and cryo-immunological features. In strongly indicated cases local tumour destruction by extremely low temperatures is superior to other palliative methods. Of 67 patients with rectal carcinoma treated with cryosurgery, 37 survived, 12 more than 36 months and 16 more than 24 months. Though there are only few hints indicating an increased immunological response following cryo-surgery, our investigations suggest a general influence on host's immunity by cryo-therapy.     

Cryosurgical effects on growing vessels.

Cryosurgical treatment of unresectable hepatic malignancies has proven beneficial in adults. Concerns regarding its use in children include the effect on growth and the risk of injury to adjacent structures. To test the effect of cryoablation on adjacent vascular structures in a growing animal, liquid nitrogen cryoablation was performed on a juvenile murine model. Sprague Dawley rats underwent double freeze-thaw cryoablation of the abdominal aorta with interposed liver tissue. Serial sacrifices were performed over 120 days. Comparisons were made with sham-operated controls. Overall, animal growth paralleled that of sham controls through all time points. Gross examination of aortic diameter also showed similar growth in vessel size between the groups. Histologic analysis demonstrated injury after cryoablation with smooth muscle cell vacuolization, followed by cell death. Aortic media layer collapse resulted from cellular loss, however, elastin fiber composition was maintained. Aortic patency was preserved despite evidence of cellular injury and aortic wall remodeling. An associated thermal sink effect on the opposing wall was identified. After cryoablation adjacent to the abdominal aorta in adolescent rats, vascular patency is maintained and animal growth and structural function is preserved, despite cellular injury and wall compression. These observations suggest that cryoablation may be a useful treatment adjunct in young subjects.     

Cryosurgical ablation as primary treatment in prostate cancer patients

ObjectiveCryosurgical ablation (csa) is one treatment option that has been developed and it is now recognised as a true therapeutic alternative in the treatment of localised disease. The aim of this paper is to present the preliminary experience with csa in prostate cancer from the centre in Norway.Materials and methodsA total of 132 patients with prostate cancer have been treated with CSA since September 2003. In 90 patients, csa was the primary therapy used and these patients included those with low (LR; n = 27), intermediate (IR; n = 37) and high risk (HR; n = 26) disease. Low risk patients were defined as those with T1a-T2a, n0, m0, gleason score ≦6 and prostate-specific antigen (PSA) < 10 ng/ml. intermediate risk were patients with T2b tumours or a psa level of 10-20 ng/ml or gleason score 7. high risk were defined as those with T2c tumours or gleason score > 7 or psa > 20 ng/ml. the remaining 42 patients either had locally advanced disease or had received salvage treatment after previous external beam radiation (EBRT), cryotherapy or hormone treatment. patients were evaluated at 3 and 6 months and thereafter at 6 month intervals. a voiding history was taken and the following tests conducted: uroflowmetry, residual urine.ResultsResults are presented for those patients receiving CSA as a primary therapy. Currently, the longest follow-up period is 42 months. The median observation period is 21 months and 39% of patients have been seen at the 24-month follow-up visit. No evidence of clinical progression has been observed in patients in the LR or HR group. Two patients in the IR group had clinical evidence of progression. The most common side effects seen during the first year post CSA were urinary tract obstruction and the need for removal of dead prostatic tissue or calcifications. Histological examination of the removed tissue did not shown evidence of prostate cancer. All patients in the LR and IR group that were sexually active before treatment were also sexually active on last follow-up, 37% using some kind of aid. 86% of patients in the LR and IR groups reported no bother as to sexual function.ConclusionsCSA is now recognised by the EAU as a true therapeutic alternative for the treatment of prostate cancer. Many institutions offer CSA only to older patients due to the lack of long-term data. If longer follow-up data confirm the short-term effect seen in my series, and if comparable side effects are reported in other studies, CSA might also be offered as primary treatment to younger patients.     

Cryosurgical modification of retrograde atrioventricular conduction. Implications for the surgical treatment of atrioventricular nodal reentry tachycardia

Paroxysmal supraventricular tachycardia resulting from atrioventricular nodal reentry is a common arrhythmia that usually responds to medical therapy. When atrioventricular nodal reentry tachycardia is refractory to medical therapy, cryoablation or endocardial catheter ablation of the His bundle has been employed to protect the ventricles from the tachycardia. However, these techniques necessitate implantation of a permanent ventricular pacemaker. A cryosurgical procedure that ablates the anatomic-electrophysiologic substrate for atrioventricular nodal reentry tachycardia while preserving antegrade atrioventricular conduction has been described. The purpose of the present study was to determine the effects of this procedure on retrograde atrioventricular conduction and on the ventricular echo phenomenon in particular. Thirty adult mongrel dogs underwent either the cryosurgical procedure (n = 20) or a sham operation (n = 10). The animals were studied either immediately postoperatively (acute cryosurgery group and control group, n = 10 for each group) or 14 weeks postoperatively (chronic cryosurgery group, n = 10). Decremental ventricular pacing and programmed premature ventricular pacing protocols were used to determine the retrograde atrioventricular nodal conduction time, Wenckebach point, atrioventricular nodal refractory periods, and ventricular echo reflection time. No electrophysiologic alterations were noted in the sham-operated group. In the acute cryosurgery group, the retrograde Wenckebach point, atrioventricular nodal conduction time, functional refractory period of the atrioventricular node, effective refractory period of the atrioventricular node, and ventricular echo reflection time were all significantly prolonged. In the chronic cryosurgery group, no significant change in ventriculoatrial conduction was noted, but the ventricular echo phenomenon was eliminated in all but one animal. These data further document that this cryosurgical procedure is capable of ablating the anatomic-electrophysiologic substrate necessary for atrioventricular nodal reentry tachycardia while preserving atrioventricular conduction.