3.0 Discussion
An endoscopic transseptal transsphenoidal approach to the pituitary fossa has been previously described by Papay et al in 1997 and Favier et al in 2018 . Our modified transseptal approach differs from the erstwhile described methods and has several advantages:
  1. Classical transseptal approach incision is a hemitransfixion incision made at the anterior caudal margin of the cartilaginous nasal septum. The incision that we describe is positioned in level with the anterior end of the middle turbinate, standard for raising a nasoseptal flap for most pituitary surgery. This is because the length of a nasoseptal flap would be long and wide enough to seal any defects/CSF leak in the sella region. However, the incision can be made further posteriorly, anteriorly or extended to include mucosa of the floor and lateral wall of the ipsilateral nostril if one anticipates a larger anterior skull base defect or indeed unexpectedly faced with such a defect at the end of tumour resection and therein provides much more versatility and choice.
  2. Making the incision at the level of anterior end of middle turbinate leaves behind at least 2cm (or more) of a caudal strut of septal cartilage with intact mucoperichondrium on both of its sides and reliable to maintain the vascularity and minimise chance of cartilage resorption leading to loss of nasal tip support and collapse.
  3. Using a hemitransfixion incision at the caudal margin of nasal septum often require release of the nasal septum from its attachment to maxillary crest and spine. Although the septum can be reattached at the end of the procedure, this part of the septum has become unstable and might heal in a variable position to the right or left with resultant columellar deviation and nasal obstruction or columellar indrawing that might be cosmetically unacceptable.
  4. Classical transseptal approach attempts to maintain the septum – cartilage, bone and mucoperichondrial flaps on both sides in its entirety. Although laudable in its intention, this creates a significant narrower operative field concentrated in the midline of the nose particularly with respect to the total space available for instruments (especially with two surgeons operating) to move in and out. The modified approach that we propose, since it essentially follows the same steps of raising a nasoseptal flap prior to any anterior skull base surgery, uses the space in both nasal cavities familiar to skull base surgeons.
  5. Once the ipsilateral mucoperichondrial flap is brought back to the midline at the end of the procedure ensuring end to end contact at the incision site, the septum heals with no perforation in our experience (Figure 4b). It also ensures nasal airflow in two separate nasal cavities that is natural and physiological that should result in less crust formation, reduced risk of whistling noise due to septal perforation and overall improved nasociliary transport of mucous.
  6. In the event of previously unplanned need for a nasoseptal flap to repair the skull base, the flap can be released from its superior and inferior attachments (and extended as explained in I) and used without compromise to the dimensions or vascularity. This holds true in case of return to theatre for a recalcitrant CSF leak in the postoperative period.
  7. If revision procedure to the same area is required at a later date, it is still possible to raise a nasoseptal flap and, therefore, “banks” a vascular pedicled flap for the future.