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:
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.