Dear Sir,

It was a privilege to read comments [1] about our article [2] by such an illustrious group.

As they rightly pointed out, in the upper cervical spine, changing of the gamma angle may not be advisable at all. The maxillary division of the trigeminal nerve mediates the pain during maxillary fixation. Maxillary block may be the ideal anesthetic procedure. However, it is demanding and would have required the involvement of an expert in this block. To circumvent this, we infiltrated the dermis with lignocaine using an insulin syringe. A few minutes later, a longer 23-G needle was used to infiltrate the periosteum and as much of the bone as the needle could penetrate. In our opinion, it would be a simpler procedure than a block with no extra discomfort. Caution is to be kept in mind as the pin should only penetrate the thickest part of the bone to prevent a fracture and an inadvertent entry into the sinus. A bone window CT scan of this part delineates the individual variation in bone thickness and the amount of pneumatization of the maxilla. As highlighted by Tuleasca et al., jaw immobilization would be an invaluable technique for certain extra-cranial lesions.

The Leksell Icon system is definitely an improvement over Perfexion. Equipped with cone beam computed tomography (CBCT), it ensures geographical accuracy with automatic positional delivery correction along similar lines as Cyberknife radiosurgery but with better precision of 0.1 mm. The biggest argument against GKRS for cervical spine lesions remains the inability to provide absolute immobilization and increased chances of target movement with physiologic activities. The infrared stereoscopic camera-based ‘high-definition motion management system (HDMM)’ facilitates frameless stereotactic radiosurgery with an accuracy of 0.15 mm even with accessory movements. However, the target movement is correlated using nose movement as an approximation. Whether the same reference point is valid for targets in the upper cervical spine before clinical utility needs to be checked further with empirical data.