Clinical Experience of Glioma Surgery Using "Tailed Bullet": Overcoming the Limitations of Conventional Neuro-Navigation Guided Surgery

PURPOSE: Although conventional neuro-navigation is a useful tool for image-guided glioma surgery, there are some limitations, such as brain shift. We introduced our methods using an identifiable marker, a "tailed bullet", to overcome the limitation of conventional neuro-navigation. A tailed bullet is an identifiable tumor location marker that determines the extent of a resection and we have introduced our technique and reviewed the clinical results. MATERIALS AND METHODS: We have developed and used "tailed bullets" for brain tumor surgery. They were inserted into the brain parenchyma or the tumor itself to help identify the margin of tumor. We retrospectively reviewed surgically resected glioma cases using "tailed bullet". Total 110 gliomas included in this study and it contains WHO grade 2, 3, and 4 glioma was 14, 36, and 60 cases, respectively. RESULTS: Gross total resection (GTR) was achieved in 71 patients (64.5%), subtotal resection in 36 patients (32.7%), and partial resection in 3 patients (2.7%). The overall survival (OS) duration of grade 3 and 4 gliomas were 20.9 (range, 1.2-82.4) and 13.6 months (range, 1.4-173.4), respectively. Extent of resection (GTR), younger age, and higher initial Karnofsky Performance Status (KPS) score were related to longer OS for grade-4 gliomas. There was no significant adverse event directly related to the use of tailed bullets. CONCLUSION: Considering the limitations of conventional neuro-navigation methods, the tailed bullets could be helpful during glioma resection. We believe this simple method is an easily accessible technique and overcomes the limitation of the brain shift from the conventional neuro-navigation. Further studies are needed to verify the clinical benefits of using tailed bullets.

Stereotactic Resection of the Brain Tumor Using 'Tailed Bullets': Technical Note

The interactive image-guided stereotactic system can provide a real-time surgical localization and guidance for complete removal of the tumor. However, this system has limitation with respect to the resection of deepseated tumors because once the tumor is removed, the brain and the margin of tumors shift toward the area previously occupied by the tumor. We present a new operative technique for determining the resection margin of deep-seated tumors using a visual marker called a 'tailed bullet' to overcome the problem mentioned above. Preoperative enhanced computed tomograms or magnetic resonance imagings were performed with the aid of the Leksell frame. The enhancing margin of the tumor was defined as a resection margin. Several points(10-15) of the tumor margin on the enhanced imaging were chosen and localized. After usual craniotomy, multiple tailed bullets were inserted into the target point just before the opening of the dura. As the tumor was removed, the brain began to move along with the tailed bullets, thus enable us to continue tracking the tumor margin by following the bullet's location. There are substantial benefits of this surgical technique. It can be easily applied to any kind of stereotactic frame without incurring other expenses and it is more cost-efficient than the neuronavigation system. This surgical procedure is also safe and simple to use for overcoming the limitation of neuronavigation system, since the movement of the bullets with the brain can be easily traced thus lowering the mortality and morbidity of brain tumor resection. This surgical technique is especially useful in glioma surgery.