This research experimentally investigated effects of injection pressure, formation chamber and bypass flow on spray performances and cryogenic characteristics of CO2 snow under cryosurgery guided by endoscopic. Results show that CO2 snow has a superior freezing capability in the application of cryosurgery. The length of formation chamber is an effective design parameter to control spray performances and cryogenic characteristics. Increase in the length of formation chamber can increase snow size and conversion ratio, as well as the cooling rate and impact area of the tissue. Thus, it is suitable for the application on wider range nidus. Moreover, the bypass flow can efficiently modulate the cooling effect of the main flow with CO2 snow particles, and extend the operation time of cryosurgery. The experimental results also show that decrease the cylinder pressure, decrease the length of formation chamber, and increase the diameter of bypass apertures can slow down the flying velocity of CO2 snow which are effective methods to control the jet velocity and prevent the risk of penetration.

A Stefan problem is a free boundary problem where a phase boundary moves as a function of time. In this article, we consider one-dimensional and two-dimensional enthalpy-formulated Stefan problems. The enthalpy formulation has the advantage that the governing equations stay the same, regardless of the material state (liquid or solid). Numerical solutions are obtained by implementing the Godunov method. Our simulation of the temperature distribution and interface position for the one-dimensional Stefan problem is validated against the exact solution, and the method is then applied to the two-dimensional Stefan problem with reference to cryosurgery, where extremely cold temperatures are applied to destroy cancer cells. The temperature distribution and interface position obtained provide important information to control the cryosurgery procedure.

Large excisions or Mohs’ micrographic surgery (MMS) are often the suggested treatments for non-melanoma skin cancers (NMSCs) of the external ear. This five-year follow-up attempts to evaluate whether curettage-cryosurgery could be an alternative therapy for selected auricular NMSCs.

One hundred auricular NMSCs, selected at a skin tumour clinic, were treated by a thorough curettage, with different-sized curettes, followed by cryosurgery in a double freeze-thaw cycle. Seventy-seven basal cell carcinomas (BCCs), 13 squamous cell carcinomas (SCCs), six SCCs in situ, and four basosquamous carcinomas were included. The mean diameter of the tumours was 18 mm (range 5–70). Morphoeiform BCCs, recurrent BCCs with fibrotic component, and most of the SCCs were selected for MMS.

Seventy-one patients with 81 tumours were followed-up for at least five years with only one recurrence. Nineteen patients with 19 tumours, followed-up for two to four years, died from other causes with no sign of recurrence at their last visit. Patients followed-up for less than two years were excluded. No major problems were registered after treatment. The cosmetic result was good or acceptable in most patients.

In carefully selected patients a thorough curettage followed by freezing with liquid nitrogen in a double freeze-thaw cycle could be a safe and inexpensive therapy even for large NMSCs of the external ear.

We report a patient who suffered negative pressure pulmonary oedema because of tracheal obstruction after cryotherapy to granulation tissue in the trachea. The pathophysiology and clinical course of negative pressure pulmonary oedema is described. Though there are reports of negative pressure pulmonary oedema after airway obstruction, to our knowledge this is the first case reported after cryotherapy.

A variety of surgical procedures are performed for treatment of hypertrophic inferior turbinates, but there is no completely effective therapy. We evaluated subjectively and objectively 52 patients who underwent one of two procedures: partial inferior turbinectomy (PIT) or cryosurgery of the inferior turbinates (CS). The results of PIT showed good functional results in 77 per cent of cases for long-term effectiveness. The results of CS showed that effectiveness was reduced from a 62 per cent success rate after one year to 35 per cent later, but CS was a simple procedure which was performed on an outpatient basis with no postoperative morbidity.

Cryotherapy is an established method of treating hypertrophic obstructive inferior turbinates. The long-term effectiveness of the technique is assessed in this study, using the need for alternative nasal surgery as an objective way of distinguishing success from failure. Over 50 per cent of patients with obstructive symptoms, including those with minor septal deviation or allergy derived lasting benefit from the technique. Cryotherapy is an effective means of treating nasal obstruction due to mucosal hypertrophy of the turbinates and may replace the need for more radical surgery.