The majority of spinal surgery performed is for the treatment of degenerative spine diseases. The history of surgical treatment for degenerative spine diseases began after Mixter and Barr reported the surgical removal of cervical and lumbar herniated discs in 1934. Since then, many forms of degenerative spine diseases, such as cervical and lumbar disk herniation, cervical and lumbar spinal canal stenosis, and degenerative lumbar spondylolisthesis, have been studied and treated. There have been many new surgical techniques and operative procedures reported in the literature, which can be confusing. New techniques usually build on ideas that have been previously attempted. This review of the history of surgical treatment for degenerative spine diseases may help readers understand the basis of our current clinical practice.

  The incidence of degenerative spine disease has been rapidly rising because of the increasing number of elderly. In recent years, minimally invasive spinal surgery has been an option for elderly patients who can often not undergo conventional surgical methods. As a result, the number of surgeries for degenerative spine disease has been increasing.

  Spinal degenerative diseases involve static and dynamic factors. Additionally, age-associated degenerative changes induce anatomical spinal changes (in the ligamentum flavum, the intervertebral disc, etc.) that differ from the characteristics present in intracranial disorders. Neurosurgeons need to consider this when diagnosing spine disorders.

  In this article, we give an overview of minimally invasive spinal surgery for lumbar spinal degenerative diseases, focusing on the surgical options available for lumbar spinal canal stenosis.

  Spinal arteriovenous (AV) shunts are a rare spinal vascular disorder that can cause progressive myelopathy due to venous hypertension or hemorrhage. Disease concepts, historical changes in treatment, current problems, and future perspectives are summarized. Between 1980-1990, direct surgery was the primary treatment choice. In 2000-2010, angiography advances enabled the visualization of previously invisible microvessels. Additionally, the development of glue materials has made endovascular treatment more popular. In the last 10 years, epidural AVFs that mimic dural AVFs have been reported. Accurate localization of the fistula of spinal AV shunts is challenging because the fistula is extremely small. Comparisons between surgical, endovascular treatment, and a combination of the two should be made.

  This article presents the medical and social problems in spine surgery for the next 5-10 years in Japan. The following 3 issues are discussed, 1) minimal invasive spine surgery (MISS) for elderly patients, 2) intraoperative monitoring for surgical safety, and 3) virtual reality simulation for presurgical planning and operative education.

  1) MISS in the elderly

  MISS was developed to treat spine diseases while avoiding significant damage to the muscles surrounding the spine. This results in less pain after surgery and a faster recovery, which is especially helpful for elderly patients. Minimally invasive procedures can shorten hospital stays. The exact length of time needed in hospital will vary. However, in general, after MISS patients go home on the same day or within 1 to 2 days. Due to our increasingly aging society, less invasive techniques will become increasingly important.

  2) Intraoperative monitoring for surgical safety

  Intraoperative monitoring of motor evoked potentials (MEPs) and somatosensory evoked potentials (SSEPs) has been recently investigated as a means of preventing motor deficits associated with spinal operations. The combination of these techniques is known as concomitant multimodal intraoperative monitoring and could be a helpful tool in spinal surgery since it is associated with a high specificity and sensitivity for detecting intraoperative neural damage. Also, post-tetanic MEPs (p-MEPs) can be used to improve the reliability of monitoring motor function during spinal surgery, especially in complicated cases.

  3) Virtual reality (VR) simulation for educating young surgeons

  Advances in computing have enabled continued growth in VR, visualization, and simulation technologies. VR-based simulators are becoming common in some surgical subspecialties, and 3-dimensional (3D) imaging data can be used to further understand complex anatomical relationships in specific patients. From our recent experience, VR simulations of spinal surgery and neurosurgery were quite useful for understanding the complicated spatial relations of anatomical landmarks and in examining surgical approaches. Planning with interactive computer graphics helps to improve the surgical effect, which in turn decreases morbidity. Additionally, VR could be used for educating young spinal surgeons.

  Most pediatric patients with moyamoya disease have cerebral ischemic symptoms. Surgical revascularization is widely performed to improve the ischemic condition. During the treatment or follow-up periods, periventricular anastomosis, which is known to be a risk for intracranial hemorrhage, is sometimes observed. In this study, we analyzed the change of periventricular anastomoses after surgical revascularization in pediatric patients with moyamoya disease.

  This retrospective study included 60 cases of pediatric (younger than 15 years old) patients with moyamoya disease who underwent surgical revascularization for the middle cerebral artery territory. Periventricular anastomoses were evaluated in the images using magnetic resonance angiography. The changes before surgery and at least 3 months after surgery were compared. Lenticulostriate anastomoses were observed in 26 cases before surgery and 4 cases after surgery. Thalamic anastomoses were observed in 23 cases before surgery and 18 cases after surgery. Choroidal anastomoses were observed in 39 cases before surgery and 17 cases after surgery. The periventricular anastomosis score after surgery was significantly higher in cases that showed stenosis or occlusion of the posterior cerebral artery (p＜0.01), especially if thalamic anastomoses remained (p＜0.01). In the analysis of 5 cases that showed stenosis or occlusion of the posterior cerebral artery and underwent additional surgical revascularization for the posterior cerebral artery territory, almost all thalamic or choroidal anastomoses decreased after surgery.

  In pediatric patients with moyamoya disease who show stenosis or occlusion of the posterior cerebral artery, periventricular anastomosis can be prone to remain after surgical revascularization for the middle cerebral artery territory. Surgical revascularization of the posterior cerebral artery territory can contribute to a decrease in periventricular anastomosis.