Bronchoscopic Cryotherapy MGR Review Bronchoscopic Cryotherapy 호흡기내과 R4 박유민 / Prof 박명재

Introduction Definition Cryotherapy(also known as cryosurgery) is the therapeutic application of extreme cold for the local destruction of living tissue

Cryoadhesion Related phenomenon It refers to using a cryoprobe to freeze material, thereby causing the material to adhere to the cryoprobe so that it can be removed

Basic principles The core temperature needed for a lesion to be destroyed is between -20ºC and -40ºC Freezing to -40ºC or below at a rapid rate (-100ºC per minute) results in more than 90 percent cell death The tissue should be thawed slowly

Increase in size of intracellular ice crystals Intracellular ice crystals can cause cell death directly by damaging mitochondria or other micro-organelles Cellular dehydration and a toxic increase in the concentration of intracellular electrolytes The result is cell swelling and rupture

Induces microvascular changes Initial vasoconstriction of arterioles and venules Modification of vascular endothelium Increased permeability of vascular walls Increased blood viscosity Lower intracapillary hydrostatic pressure Decreased blood flow Formation of platelet plugs Thrombosis of the feeding vessels

The amount of tissue destroyed by cryosurgery Cooling/thawing rate The minimal temperature achieved The water content of the cells The number of freezing and thawing cycles The sensitivity of the tissue Cryosensitive : skin, mucous membrane, granulation tissue, and tumor cells Cryoresistant : fat, cartilage, fibrous, and connective tissue

Equipment Bronchoscope Cooling agent(Cryogen) Cryosurgery device (Cryoprobe+transfer line+console)

Equipment Bronchoscope(rigid or flexible) Cooling agents Liquid nitrogen(N2) and nitrous oxide(NO2) Joule-Thomson effect

Equipment Cryosurgery device Cryoprobe : used to freeze the target tissue Rigid, Semirigid : rigid bronchoscope only Flexible : either a flexible or a rigid bronchoscope

Transfer line : line connects the cryoprobe to both the cooling agent storage container Console : controls the flow of cooling agent through the transfer line

Indication A palliative therapy for airway obstruction due to a malignancy Usually in patients who cannot tolerate lung resection (Poor respiratory function, inoperable due to the proximity of the tumor to the carina, underlying health conditions) Airway obstruction due to benign endotracheal or endobronchial lesions Inoperable microinvasive carcinoma, and hemoptysis due to visible benign or malignant lesions Cryoadhesion can be used to extract foreign bodies, mucous plugs, or blood clots and biopsy specimen

Follow-up bronchoscopy Generally performed eight to ten days after bronchoscopic cryosurgery The repeat examination allows the extent of tissue destruction to be assessed Sloughing material can be removed by forceps, aspiration, or cryoadhesion If necessary, additional bronchoscopic cryotherapy can also be performed

Possible complications There are few cryosurgery-specific contraindications Hemorrhage Pneumothorax/Subcutaneous emphysema Reactive airway edema Complictaion due to extracted tissue migration Anesthesia related complications

Procedure The preparation and initiation of bronchoscopic cryosurgery are identical to that for conventional flexible or rigid bronchoscopy Pooling-out using cryoadhesion for recanalization, and biopsy Repeating freezing/thawing for devitalization https://www.youtube.com/watch?feature=player_embedded&v=RNLYD4f6p4w

Clinical outcomes Treatment of airway obstruction Endoscopic Cryotherapy of Lung and Bronchial Tumors: A Systematic Review Korean J Intern Med 2011;26:137-144

Endoscopic Cryotherapy of Lung and Bronchial Tumors: A Systematic Review Korean J Intern Med 2011;26:137-144

Endoscopic Cryotherapy of Lung and Bronchial Tumors: A Systematic Review Korean J Intern Med 2011;26:137-144

Endoscopic cryotherapy generally showed high treatment efficiency in approximately 80% of cases, although there was variation depending on operation methods or target patient groups It was also effective in improving quality of life, improving symptoms, like dyspnea, and improving pulmonary function Endoscopic Cryotherapy of Lung and Bronchial Tumors: A Systematic Review Korean J Intern Med 2011;26:137-144

Clinical outcomes Biopsy using cryoadhesion Cryobiopsies extracted from perfused tissue are larger than forceps biopsies Prospective Controlled Animal Study on Biopsy Sampling with New Flexible Cryoprobes versus Forceps: Evaluation of Biopsy Size, Histological Quality and Bleeding Risk Respiration 2010;80:127–132

Cryospecific artifacts were not observed Cryobiopsies are structurally intact, and tissue integrity is not impaired by the freezing process The artifact-free area was 95% for both, forceps and cryobiopsy samples Cryospecific artifacts were not observed Prospective Controlled Animal Study on Biopsy Sampling with New Flexible Cryoprobes versus Forceps: Evaluation of Biopsy Size, Histological Quality and Bleeding Risk Respiration 2010;80:127–132

Conclusion Endobronchial cryotherapy is an effective and less expensive procedure for the management of central airway obstruction Tissue biopsy using cryotherapy is very effective