See: Case Example Transphenoidal Approach to Pituitary Tumor

Return to: Paranasal Sinus Surgery Protocols

See also: Pedicled nasoseptal flap (Hadad-Bassagasteguy flap) protocol

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GENERAL CONSIDERATIONS

1. Consideration: The transphenoidal approach is suitable for midline lesions arising from the pituitary fossa that may extend into the suprasellar, clivus, sphenoid sinus of nasal cavity including pituitary adenomas, meningiomas, craniopharyngiomas, sella and clivus.
   1. Brief history of approaches to patients is helpful: (ie craniotomy to transpalatal to transnasal endoscopic approach). Highlighting the advantages of transnasal endoscopic approach which include improved visualization, decreased blood loss, and decreased hospital stay.

PREOPERATIVE PREPARATIONS

1. Nasal anatomy 
   1. History of nasal trauma, sinus surgery, sinus disease 
2. Obstructive sleep apnea: use of CPAP (the immediate use of CPAP after surgery is contraindicated secondary to potential pneumocephalus from nasal passageway). Patients must wait for at least one month following surgery.
3. Review of pre-op imaging (CT and or MRI) is important. Particular attention should be paid to the relationship of the mass to surrounding critical structures:
   1. Carotid artery
   2. Optic nerve
   3. Cavernous sinus
   4. Presence of suprasellar extension should also be examined

NURSING CONSIDERATIONS

1. Room Setup
   1. Large room is required to accommodate two scrub nurses (one for each service)
   2. Stealth setup
   3. Patient is rotated 180 degrees. 
2. Instrumentation and Equipment
   1. Stealth setup (sterile)
   2. Endotower with video monitor and recording device
   3. Endoscrub (camera washing system)
   4. Medtronic XPS (microdebrider/drill unit)
3. Medications (specific to nursing)
   1. Cocaine (intranasal anesthesia with vasoconstriction)
   2. Afrin (vasoconstriction)
   3. 1% Lidocaine with 1:100,000 Epinephrine (local injection with tonsil or spinal needle) 
4. Due to intracranial access, sterile prep is required for nasal procedure
5. Abdomen is usually prepped in case of need for abdominal fat graft
6. Nasopore (absorbable nasal packing) is used

ANESTHESIA CONSIDERATIONS

1. Patients with Obstructive sleep apnea (OSA) and CPAP use must be identified prior to surgery. CPAP use in the immediate postoperative period is contraindicated secondary to possibility of pneumocephalus.
2. At start of case, patient is intubated (tube taped to left lower lip), arterial line placed (preferably on patient's left arm), foley placed, and bed rotated 180 degrees. Neurosurgery will then place the patient in pins with Mayfield headrest for fixation.
3. Arterial lines are usually placed for any case with anticipated intracranial/intradural dissection.

OPERATIVE PROCEDURE

1. Greater palatine injection via the oral cavity.
2. Initial decongestion of nasal cavity with pledgets soaked in 4ml of 4% Cocaine or 1% lidocaine with 1:100,000 epinephrine combined with Afrin (oxymetazoline).
3. Registration of Stealth with CT scan:
   • Ensure patient’s name and number in video system. Have flash drive to save case at end of day for your portfolio.
   • Have the patient’s images loaded (either via intranet or via DICOM images from stealth CD). The stealth algorithm for neuro cases is different than oto, often the images do not include the entire patient’s face.
   • Ensure that the setup is for a neuro case (the scan will then be loaded flipped).
   • NSG will place the patient in pins. Ideal head location is to have the patient’s head rotated towards the right (towards you).
   • Register off the field (ensure stealth balls are all well seated). Can check the proximity of the sensor and instruments on the machine.
   • Remove the stealth sensor and have nurses begin to prep the face as well as the abdomen.
   • Ensure that they also prep the holder for the stealth star, place a tegaderm over the holder. Drape, then cut down on the stealth insert, place stealth star over area.
4. Prep of face / abdomen (potential fat graft harvest)
5. Visualization of intranasal anatomy with 0 degree scope 
6. Instruments that are required at the beginning of the case: endoscrub, microdebrider, suction, and 0 degree endoscope.

• Set up Mayo stand in front of where you are standing and place the most commonly used instruments there (freer, curette, sickle knives).
• White balance and focus endoscope. Zoom in to ensure the largest field of view on the monitor.
• Remove pledgets and inspect bilateral nasal cavities.
• Using tonsil needle (rigid long needle bent at 45 degree angle), inject the anterior face of the middle turbinate as well as the axilla of the middle turbinate. The axillary injection is best performed by placing the needle submucosal anterior to the axilla and sliding it forwards while injecting. A great injection will also travel to the anterior face of the MT.
• Use the curved out side of blunt freer (to minimize bleeding) all the way towards the posterior end of the middle turbinate and gently lateralize the MT to visualize the superior turbinate. One can also lateralize the superior turbinate. You may be able to visualize the sphenoid os at this point.
• Now that you have some room medially, inject the posterior aspect of the septum.
• You may need to resect the inferior 1/3 of the superior turbinate to gain clear exposure to the sphenoid os. Retest the stealth probe for accuracy at this time.
• Identify sphenoid os and enlarge inferiorly and medial until you reach the septum. Visualize the unilateral sphenoid. Review where the sphenoid septum is, which way it turns, and if it is attached to carotid. Proceed to small posterior septectomy. This can be performed with backbiter, microdebrider, or sickle.
• Repeat the process on the patient’s contralateral side.
• Using the microdebrider or the drill, remove a small posterior septectomy. The key for instrument manipulation is to bring the rostrum down to the base of the sphenoid.
• Use stealth to confirm position intermittently.
• Identify in the sphenoid sinus: the sella, planum, tuberculum, carotid arteries, and optic nerve.
• Remove intersinus septum until it is flush to the posterior face of sphenoid. One needs to be gentle and not twist off pieces of the septum as it can fracture the carotid. A drill can be used to bring this flush.
• Once access is completed, call NSGY, identify anatomy, and illustrate where carotid/optic nerve is located.

REFERENCES

Liu J.K., Weiss M.H., Couldwell W.T.: Surgical approaches to pituitary tumors. Neurosurg. Clin. N. Am.  2003; 14:93-107.Reading

Christoph Hofstetter, Vijay K. Anand, Theodore H. Schwartz.  Endoscopic transsphenoidal pituitary surgeryOperative Techniques in Otolaryngology-Head and Neck Surgery,Volume 22, Issue 3,September 2011,Pages 206-214