Atlantoaxial Stabilization Using C1 Lateral Mass and C2 Pedicle/Translaminar Screw Fixation by Intraoperative C1- and C2-Direct-Captured Navigation with Preoperative Computed Tomography Images

In C1–C2 posterior fixation, the C1 lateral mass and C2 pedicle/translaminar screw insertion under spine navigation have been used frequently. To avoid the risk of neurovascular damage in atlantoaxial stabilization, we assessed the safety and effectiveness of a preoperative computed tomography (CT) image-based navigation system with intraoperative independent C1 and C2 vertebral registration. It is ideal when a reference frame can be linked directly to the C1 posterior arch for C1-direct-captured navigation, but there is a mechanical challenge. A new spine clamp-tracker system was implemented recently, which allows reliable C1- and C2- direct-captured navigation in nine patients with traumatic C2 fractures. In this way, there was no misalignment of C1–C2 screws. C1 lateral mass screws were used except for one case, and translaminar screws were primarily used as an anchor for C2. The C1 lateral mass screw locations, which are 19 mm laterally from the C1 posterior arch’s center, are taken to be constant. However, there is one unusual circumstance in which using a C1 laminar hook instead of a C1 lateral mass screw appears to be a beneficial substitute. The increase of surgical accuracy for posterior C1–C2 screw fixation without cost constraints is significantly facilitated by intraoperative C1- and C2-direct-captured navigation with preoperative computed CT images.

Traumatic pericallosal artery aneurysm

Pericallosal artery aneurysms comprise about 1.5 to 9% of all intracranial aneurysms. Some of them are caused by head injury. We report a 66-year-old male patient with ruptured left pericallosal artery aneurysm, 2.6 x 3.2 mm in size. The patient fell 2 months ago. Operation was done under right interhemispheric approach. The parent artery was avulsed while the clip was adjusted. The avulsed part was sutured and postoperative CAG revealed totally obliteration of the aneurysm while the repaired artery was patent. The patient recovered well after operation

Fundamentals of AVM surgery: an institutional experience

Arteriovenous malformations [AVM] of the brain are congenital lesions and remain dormant for many years but can haemorrhage, cause seizure or impair brain function. Modern therapeutic modalities for AVM include microsurgery, intravascular neurosurgery and stereotactic radiosurgery. There is significant risk of intraoperative haemorrhage due to abnormal vessels as well as due to change in haemodynamic pattern of surrounding brain after excision. Inadequate coagulation of feeding vessels and draining channels, loss of plane between nidus and normal brain, persistent residual or daughter sinus and inadequate intraoperative blood pressure control are the main causes of haemorrhage. The main important aspect in AVM surgery is to identify the plane between the nidus and normal brain and work around the nidus. It is very important to aggressively reduce intraoperative haemorrhage and prevent or minimize the dilation of abnormal capillaries and arteries on the basis of fundamental surgical strategy, i.e., feeder-nidus-drainer. Adequate control is the key factor in prevention and treatment of haemorrhage. In a period of 8 years, from 1994-2003, our department dealt with 290 cases of AVM. In 212 patients, operative removal was performed, which included 89 cases with intracerebral haematoma. In 39 cases, embolisation and/or gamma knife was preferred