In recent years, with the rapid development of radiological medical imaging technology, gamma knife surgery has been improved. With more accurate focusing and more precise radiation dose design, gamma knife surgery significantly reduced the complication rate, and it can treat a wider range of diseases. Currently, the application of gamma knife stereotactic radiosurgery in ophthalmology has increased, and better outcomes have been obtained in the treatment of ocular diseases. For eye diseases that are difficult to operate on, the gamma knife surgery controls tumor growth while avoiding surgery damage. It has advantages in terms of improved appearance, treatment cost and psychological trauma, and can be used as a preferred method for treating ophthalmic diseases or as an adjunctive treatment after surgery. This article provides an overview on the application history, therapeutic principles, treatment in ophthalmic diseases and complications of gamma knife, in order to contribute to the further application of the gamma knife in ophthalmology.

Objective:To evaluate the clinical outcomes of neutral wedge osteotomy assisted by determination of the center of rotation of angulation (CORA) at the distal humerus anatomical axis for cubitus varus deformity in children.Methods:From 2016 to December 2019, 20 children with cubitus varus after supracondylar fracture of the humerus were treated at Department of Orthopeadics, Children's Hospital of Wujiang District. They were 8 boys and 12 girls, aged from 4 to 12 years (average, 7.0 years). Standard anteroposterior X-ray films of bilateral humerus were taken preoperatively for measurement of Baumann angle, proximal anatomical axis (PAA) and distal anatomical axis (DAA) of bilateral humerus to determine the CORA and the varus deformity angle. A lateral closed neutral wedge osteotomy was performed around the CORA to correct the varus deformity. All children were immobilized with elbow plaster cast after operation. Elbow flexion and extension function, postoperative scar, and body surface carrying angle were recorded. The carrying angle and Baumann angle were also measured on elbow X-ray films. Elbow function was evaluated according to the modified Flynn elbow score at 24 months after operation.Results:All patients were followed up for 24 to 36 months (mean, 29.3 months). Elbow hyperextension was close to normal in 18 cases, and 5° hyperextension existed in 2 cases. The flexion was greater than 130°, averaging 133.1° (from 130° to 138°), in 15 patients. The flexion ranged from 110° to 130° in 5 patients. The Baumann angle was 99.0°±1.0° preoperatively and 76.0°±1.0° postoperatively; the carrying angle was -14.0°±1.0° preoperatively and 13.6°±1.0° postoperatively. There were significant differences between the above items between preoperation and postoperation ( P<0.05). According to the modified Flynn elbow score at 24 months after operation, the elbow function was excellent in 16 and good in 4 cases. The varus of 40° was corrected during surgery in one child. Fixation failure or correction failure occurred in none of the children before removal of the plaster or the Kirschner wire. Conclusions:In neutral wedge osteotomy assisted by determination of the CORA at the distal humerus anatomical axis, the CORA and angulation of the distal humerus inversion can be accurately determined so that the osteotomy line and the angulation correction axis can pass through the CORA to restore the humerus alignment with no displacement of the broken ends.