I meen that in those patients the neck anatomy could be disturbed 

Preoperative preparation with CT; 

Many centers add intraoperative identification via C-arm, or ultrasound.

Endoscopic-assisted percutaneous tracheosotomy is another option. 

Is the question how do we best assess the tumor and take biopsies?  in which cases I would use CT and a flexible endoscope with a working channel for biopsies i local anesthesia.

Or is the question how do we best prepare for the management of a difficult airway in which case I would do an ultrasound of the neck (trachea) and a preoperatively flexible laryngoscopy. If the visualization of the endolarynx is severely obscured one could opt for a tracheostomy i local anesthesia but in our department the standart approach would be fiberoptic endotracheal intubation with a head and neck surgeon standing by for the possible emergency surgical airway.

thanks Dr.sherif ,Dr Jacob

actually the question concerned about the airway assessment to prepar the patient for next step of mangement which could be endotracheal intubation and \or tracheaostomy 

I think US is diffecult but preoperative and intraoperative CT is the best or intraoperative C_arm is another alternative 

Preoperative CT is a basic part of the initial workup off the patient .However it is the interpretation of the images which differ. In this context a sagittal reconstruction with virtual endoscopy can give you an insight of what too expect. This combined with a flexible nasolaryngoscopy will outline the airway. In patients with purely pharyngeal lesions airway difficulties are usually not related to the lesion but rather too the patient's configuration. In all cases an attempt of atraumatic flexible intubation is started with tracheostomy stuff hand. Percutaneous trachs are usually not suitable for these patients

Pro-operative CT is always invaluable tool to assess laryngotracheal airways in Pharyngeal tumors. Flexible laryngoscopy is for endolaryngeal assessment if the pharyngeal tumor is small enough to allow for visualization of the larynx. But for huge pharyngeal tumors causing severe airway obstruction, we often find visualization of the larynx very difficult and sometimes impossible. In such situations in our center, we often rely on clinical assessment and  pre-operative CT for tracheostomy in these patients

I agree that a CT would be a part of the initial workup of such a patient but I fail to see its value in assessing the potency of the airway. I would argue that in the case presentet by Dr. Orji a CT is an unnecessary risk in a patient with a compromised airway.