Coblator Use in Endonasal and Transcranial Neurosurgical Procedures

Background Skull base lesions are notorious for their access difficulty, thus there is a continuous need to develop and use new tools. The coblation (controlled ablation) is designed for ablation, resection, coagulation of soft tissue, and hemostasis of blood vessels. It is mostly used in otorhinolaryngology (ENT) surgery. Other neurosurgical uses were described in sciatic and femoral nerves ablation in phantom limb pain. It is also used in transnasal encephalocele repair as it offers shorter period of resection when compared with bipolar use.

Coblator uses pulsed electrical current through a medium (normal saline or lactated Ringer) which creates excited highly energetic sodium, hydroxyl, and hydrogen radicals. The plasma layer is localized around the electrodes. This causes tissue destruction through the interactions of the above ions with the surrounding tissue. The effect is purely chemical and not thermal. The Coblator does not produce high temperature (40−70°C) as opposed to other thermal coagulation tools (400−600°C). The benefit of using the Coblator is causing less thermal injury to the surrounding tissue comparing to other methods.

There are two settings in the Coblator: the coblation and the coagulation modes. When coblation setting increases, the thermal effect decreases.

Here, we describe our experiences with the use of Coblator for intracranial surgeries.

Table 1 List of patients for whom the Coblator was used

Patient no.	Pathology	Type of surgery	Indication for usage	Patient history
1	Convexity/parasagittal hemangiopericytoma	Craniotomy	Highly vascular tumor	45-y-old woman who presents with right-sided weakness and imaging showing very large extra-axial mass
2	Encephalocele	Endonasal	To shrink encephalocele	48-y-old woman who presents with CSF rhinorrhea and imaging showing ethmoidal meningoencephalocele
3	Encephalocele	Endonasal	To shrink encephalocele	68-y-old woman who presents with CSF rhinorrhea and imaging showing left lateral sphenoid meningoencephalocele
4	Nasal/anterior skull base tumor, teratocarcinosarcoma	Endonasal	Vascular tumor	65-y-old man who presents with feeling of fullness and imaging showing nasal cavity/cribriform mass

Discussion Our indications for the cases mostly fall under two categories:

1. Highly vascular tumor (either transcranial or endonasal)

2. Encephalocele repair.

The use of Coblator in encephalocele repair helps shrink the herniated brain while minimizing thermal injury to the surrounding normal brain. The advantage of using the Coblator in vascular tumor is the combination of ablation and coagulation.

While the clear benefits of the Coblator are noticeable, we have to be cautious regarding its injury to the surrounding tissue. There is more fibrosis in the mucosal cavity compared with the other coaglulative tools. We observed some periencephalocele edema postoperatively.

Conclusion This is the first study to describe the use of the Coblator in transcranial cases. More work has to be done to assure the safety of the Coblator when used in direct contact with the brain.