fenestrated, 10.0 mm wide x 18.0 mm deep, 8″ (20.0 cm)?Cushing Decompression Retractor is made for use in treatment of spinal nerve and nerve root decompression surgeries that can be caused by spinal stenosis and intervertebral disc herniation. This is a very specialized instrument made for a very specific neurosurgical use. Additionally this retractor is fenestrated.