Objective
This study aimed to describe the surgical technique in patients with cervical herniated disc treated with unilateral biportal endoscopic spinal surgery.
Materials and Methods
Working and viewing portals were created in each unilateral paravertebral area at the target disc level. Under exploring by endoscopic view, effective decompression was possible via safe access to the medial foramen with minimal laminectomy and facetectomy. We evaluated 27 patients, and clinical outcome was analyzed using the visual analogue scale (VAS), Neck disability index (NDI), Macnab criteria, and motor function of involved upper extremity, all assessed before and 3, 6 months post procedure.
Results
The VASs for axial neck pain and upper extremity pain decreased from 6.8 to 1.9 and 7.7 to 1.5, respectively, at 6 months post procedure. The NDIs were improved from 45.5 to 13.0 at 6 months post procedure. According to the Macnab criteria, an ‘Excellent’ , ‘Good’ , and ‘Fair’ result was obtained in 55.6%, 29.6%, and 14.8% subjects, respectively. The motor power of involved upper extremity improved as an approximately one grade on average at 6 months post procedure; 3.9±0.8 to 4.8±0.4.
Conclusions
Unilateral biportal endoscopic spinal cervical surgery can be an efficient and safe intervention in patients with cervical herniated disc.

Introduction
We describe the complications that can occur after percutaneous vertebroplasty using bone cement for osteoporosis vertebral compression fracture. Main subject: The most common complication of percutaneous vertebroplasty is the leakage of bone cement. Leakage of bone cement has been reported variously and could leak into the spinal or neural foramen, adjacent intervertebral disc and soft tissues around the spine, and venous systems. The most serious complications are neurologic symptoms due to spinal cord and nerve root compression and complications associated with death due to heart and pulmonary embolism. In addition, recompression fracture or adjacent vertebral compression fracture might occur and various treatment methods have been proposed.
Conclusion
The complications that can occur after percutaneous vertebroplasty have been reported variously, including neurologic deficits due to the leakage of bone cement and lung and heart embolism. In addition, there is a possibility of recompression fracture or adjacent compression fracture. Therefore, you should be careful about percutaneous vertebroplasty. Finally, patients with many risk factors regarding complications of vertebroplasty would need close observation and follow-up.

Cervical ossification of posterior longitudinal ligament (OPLL) can cause cord compression which can lead to myelopathy. Operative management including anterior fusion or laminoplasty is needed in these cases. Understanding the progression course of OPLL, risk factors of progression, and risk factors of myelopathy caused by OPLL is essential to determine the necessity, timing and method of operation. Therefore, we will review the previous study results regarding characteristics and progression course of OPLL. Furthermore, the results of study about risk factors and progression course of OPLL undergoing conservative management will be discussed.

When conservative treatment fails in the treatment of osteoporotic vertebral compression fractures, a minimally invasive procedure, such as percutaneous balloon kyphoplasty or vertebroplasty is performed. Among these, balloon kyphoplasty is known as an advantageous method for lower risk of cement leakage and greater correction effect of kyphosis and better sagittal balance correction. However, there are reports of various complications during and after procedure, and sometimes result in serious consequences. This paper reviews with previous literatures about the complications related to balloon kyphoplasty.