Is there a CPT code for fenestration of septum pellucidum "without" endocscope.

Operations and procedures: Stereotactic microscopic right frontal craniotomy for biopsy and subtotal resection of third ventricular mass with fenestration of septum pellucidum.

Doctor is billing for both 61510 and 61516. I'm thinking it should be either 61510 with a 22 modifier, or an unlisted procedure code.