BACKGROUNDThe usual transbronchial coagulation techniques include microwave, argon plasma coagulation (APC), electrocautery and cryotherapy. However, there are serious clinical problems in the safety of each. By analyzing the experimental data and clinical observations, we observed the variable effects of different coagulation techniques via bronchofibroscopy, to look for an optimal interventional management of luminal bronchus diseases, and evaluate the safety and the equivalent point.

METHODSFour kinds of coagulation techniques under bronchoscopy were performed on the fresh bronchus of healthy sheep, and the pathologic changes in all groups were observed under the microscope. The different treatment parameters were as follows: microwave 60 W×1 second, 3 seconds, 5 seconds and 40 W×1 second, 3 seconds, 5 seconds; APC 40 W×1 second, 3 seconds, 5 seconds; electrocautery 40 W×1 second, 3 seconds, 5 seconds; cryotherapy 100 Ω×60 seconds, 120 seconds.

RESULTSAfter treatment, ovine bronchial mucosa in all groups showed pathologic changes such as local necrosis and amotio of the mucosa lining epithelium, local submucosa coagulative necrosis or tissue defects, while inflammation in the surrounding tissue was not obvious. Under the same output power and action time, different methods had different outcomes. The damage by APC was the most superficial, microwave was the second, and electrocautery caused the worst damage. The study also found that effects of electrocautery at 40 W×3 seconds, microwave at 40 W×5 seconds or 60 W×3 seconds, APC at 40 W×5 seconds and cryotherapy at 100 Ω×120 seconds were the equivalent point conditions. The appearance included mucosa absence, partial submucosa absence, and collagen fiber coagulation in treatment areas.

CONCLUSIONSEach coagulation technique has its own characteristic. It is very important to choose the appropriate power and action time of the suitable method according to the therapy requirement.

Animals ; Argon Plasma Coagulation ; adverse effects ; Bronchial Diseases ; pathology ; therapy ; Bronchoscopy ; Cryotherapy ; adverse effects ; Electrocoagulation ; adverse effects ; Microwaves ; adverse effects ; Sheep

To find out whether the cryotherapy for the treatment of the retinopathy of prematurity (ROP) causes structural changes of the extraocular muscle (EOM), and also whether the changes are related with the occurrence of strabismus. To examine the acute stage change, we conducted a transconjunctival cryotherapy around the superior rectus muscle of a rabbit and resected it 0, 3, 7, 14, and 28 days after the cryotherapy. In observing chronic changes, we first categorized patients who had an esotropia surgery into groups, one of which combined prematurity and cryotherapy and one group affected by prematurity but without having had cryotherapy. Then we compared the change of EOM with that of a fullterm infant group. In a rabbit, edema, acute inflammatory cells and a large amount of degenerated muscle fibers were observed immediately after the cryotherapy and on the 3rd day. On the 7th day, regenerated muscle fibers were observed and on the 14th day, the inflammatory cells decreased and the amount of regenerated muscle fiber increased. On the 28th day, abnormal findings were not observed any more and the muscle was found to be normal. When chronic changes of EOM in human on 1 1/2 to 8 1/2 years after cryotherapy, there were no abnormal findings observed in three groups. From the study, we can infer that cryotherapy can cause acute inflammation and necrosis of muscle fiber but such an acute change will improve and does not result in structural change in the long term. Therefore, the occurrence of strabismus in patients with ROP is considered to be attributable to reasons other than injury of EOM.
Animal ; Child ; Child, Preschool ; Cryotherapy/*adverse effects ; Human ; Infant ; Infant, Newborn ; Oculomotor Muscles/*surgery ; Rabbits ; Retinopathy of Prematurity/*pathology/*surgery ; Strabismus/*etiology

A 6-year-old boy was referred to our hospital with symblepharon and lateral canthal deformity in both eyes, which developed 6 years ago. The patient was born at 27 weeks gestation. He had received cryotherapy for retinopathy of prematurity. One month after cryotherapy, he developed a conjunctival scar with symblepharon in both eyes and underwent symblepharon lysis at another hospital 5 years prior. Ocular examination revealed an extensive conjunctival hypertrophic scar with symblepharon and limitation of extraocular movements. An excisional biopsy, lateral canthoplasty, and symblepharon lysis with conjunctival autograft from the contralateral eye were performed in the left eye. Histopathologic examination revealed diffuse proliferation and infiltration of collagenous tissue.
Biopsy ; Child ; Cicatrix, Hypertrophic/diagnosis/*etiology ; Conjunctiva/pathology ; Conjunctival Diseases/diagnosis/*etiology ; Cryotherapy/*adverse effects ; Diagnosis, Differential ; Follow-Up Studies ; Humans ; Male ; Retinopathy of Prematurity/*therapy

OBJECTIVETo observe the short term effect of argon plasma coagulation (APC) combined with cryotherapy via bronchoscopy for treatment of severe post-intubation tracheal stenosis in a child.

METHODA 3-year old boy was admitted for cephalothorax abdominal compound trauma and dyspnea, who had severe post-incubation tracheal stenosis. The agreement about the operation risk was signed by the parents. Endotracheal APC procedure was performed with a bronchoscope under general anesthesia. The APC probe was put into the working channel of the bronchoscope. The stenotic lesion was endoscopically visualized and then coagulated by argon plasma. Such coagulation was carried out several times at the stenotic site until it gradually became dilated. The devitalized tissue was mechanically removed with grasping forceps. Thereafter, bronchoscopic cryosurgery was repeatedly performed at the stenotic site. Clinical symptoms, signs and bronchoscopic manifestations were observed right after operation, after 1 day, 10 days, 1 month and 6 months separately.

RESULTTracheal tissue hyperplasia and cyanosis disappeared, laryngeal stridor and dyspnea improved obviously right after the operation. General condition of the patient was well, there was no laryngeal stridor and dyspnea 10 days after operation. The mucosa of the surgical site was smooth and no tracheostenosis was seen under bronchoscope at 1 month and 6 months after the operation.

CONCLUSIONArgon plasma coagulation combined with cryotherapy via bronchoscope is an effective method to treat tracheal stenosis of children, which needs further exploration for the application.

Argon Plasma Coagulation ; methods ; Bronchoscopy ; Child, Preschool ; Cryotherapy ; Humans ; Intubation, Intratracheal ; adverse effects ; Laryngeal Diseases ; etiology ; surgery ; Male ; Trachea ; surgery ; Tracheal Stenosis ; etiology ; surgery ; Treatment Outcome ; Wounds and Injuries ; surgery