To gain access to the spinal nerve root and remove a rupture…

To gain access to the spinal nerve root and remove a ruptured disc during a laminectomy/micro disc procedure, the surgeon uses a powered, handheld drill/burr (Stryker TPS or RemB) to open a small pilot hole in the bony lamina. The surgeon will typically convert to using a different cutting instrument after to avoid damaging the dura. What instrument is  used to enlarge the small hole and remove additional lamina bone?