Endoscopic endonasal transpterygoid trans lacero-cavernous resection of Knosp 4 functioning pituitary macroadenoma

In this video, we demonstrate the technique of endoscopic transpterygoid trans lacerum trans cavernous approach for the excision of Knosp 4 functioning pituitary macroadenomas. We highlight the anatomy and key steps of the approach using cadaveric dissection and present two clinical cases. A 42-year-old female with a growth hormone-secreting tumor and Knosp 4 macroadenoma underwent an extended endoscopic endonasal approach and near-total excision of the tumor. Postoperatively she was neurologically intact. Postoperative MR showed a small residue in the lateral compartment of the cavernous sinus and along the right optic tract superiorly. Due to the proximity of the residual tumor near the optic apparatus, she was offered a pterional approach, and the tumor around the optic apparatus was excised. She was given stereotactic radiosurgery for the small residual tumor in the cavernous sinus and is currently doing well, under remission. The second case was a 23-year young male with acromegaly and bilateral Knosp 4 macroadenoma. He underwent endoscopic transpterygoid trans lacerum trans cavernous approach and gross total excision of the tumor was done. He had transient bilateral ophthalmoplegia in the immediate postoperative period which recovered fully within 6 weeks. He is currently in remission without any need for radiotherapy. To conclude, an in-depth knowledge of the anatomy helps in improving surgical outcomes in extended endoscopic endonasal surgeries.