The current management of craniopharyngioma aims for complete resection, which remains the gold standard, although recurrence is a common event [8, 16, 19, 26, 28, 29]. The multitude of operative approaches to these midline deep-seated lesions reflects their challenging nature. Several factors can guide a case-specific choice of the approach:

Systematic review of these factors has a critical role when designing the appropriate surgical approach.

A pure intrasellar lesion with enlargement of the sella turcica is a well-established indication for the standard transphenoidal approach.

In case of intra-suprasellar infradiaphragmatic lesion, the sella turcica is enlarged, and the diaphragma sellae is pushed upward. In the majority of cases, a standard transphenoidal approach allows the removal of the lesion since the suprasellar part usually collapses down into the sella after the removal of the intrasellar compartment of the lesion. In case of suprasellar craniopharyngiomas, some selected cases can be treated using the transtuberculum-transplanum approach. The main steps of the procedure are:

Among supradiaphragmatic lesions, Kassam has recently proposed an approach-based classification useful when removing the craniopharyngioma from the endonasal route; he brings out four main types: pre-, trans- and retroinfundibular and lesions isolated to the third ventricle [37].

In suprasellar prechiasmatic preinfundibular lesions, the transtuberculum-transplanum sphenoidale approach provides a direct midline exposure of the tumour, which is seen immediately after dural opening. The optic nerves and chiasm are usually stretched superiorly by the tumour, and the endoscopic view from below highlights in a safe way the distal branches of the superior hypophyseal arteries, which supply the inferior surface of the optic chiasm and the pars tuberalis of the pituitary; their preservation is critical for the visual and endocrine outcome. As for transcranial techniques, tolerance of the optic system to surgical manipulation depends on its preoperative status: an optic nerve or chiasm already stretched and distorted by adjacent tumour is extremely sensitive to any type of manipulation; however, the endoscopic endonasal technique offers the opportunity to early decompress the nerves and to dissect the tumour from the nerve and not vice versa as usually occurs during transcranial procedures, thus minimizing the surgical manipulation over the optic pathways (Fig. 5.2).

Concerning retrochiasmatic retroinfundibular craniopharyngiomas, the number of surgical classifications and cranial approaches (subfrontal, pterional, transcallosal, transpetrosal) proposed for such lesions over the years reflects the difficulty in exposing them widely through a single approach. The endoscopic endonasal route provides a coaxial route to the lesion extension. The starting gate is the pituitary stalk [37]; depending on the pattern of growth of the lesion, intra- and/or para-pituitary stalk routes can be followed toward the retrosellar and even intraventricular area (Fig. 5.3).

When dealing with retroinfundibular lesions, the pituitary stalk can be preserved by running the endoscope and instruments along the para-pituitary stalk corridors and/or by mobilizing the gland upward as proposed by Kassam et al. [38]. However, such procedure requires extensive experience in endonasal skull base surgery. Furthermore, depending on downward extension in the posterior cranial fossa, retroinfundibular lesions can also require drilling of the dorsum sellae and removal of the posterior clinoids [37].

When the lesion grows into the infundibulum, the pituitary stalk is usually enlarged by the tumour, which creates a corridor to enter the ventricular chamber; since it may be hard to understand how the third ventricle can be unlocked through the nose, some considerations supporting such strategy have to be clarified. When dealing with a lesion inside the third ventricle, the possibility to apply the endoscopic endonasal technique depends on two main factors:

A craniopharyngioma which displaces the floor of the third ventricle inferiorly and enlarges the infundibulum, pushing it over the sella, creates the surgical space needed to face the lesion just after the dural opening over the suprasellar area.

Some points have to be considered when approaching such intraventricular lesions:

After tumour removal and careful haemostasis, the reconstruction of the osteodural defect is tailored in order to avoid CSF leakage. The latter is related to the degree of subarachnoid dissection and/or opening of the third ventricle.

In standard transphenoidal surgery, the integrity of the subarachnoid space is usually preserved, whereas in extended transplanum approaches wide arachnoidal opening is a prerequisite to a successful surgery. In the transtuberculum-transplanum approach, the bone window has an irregular shape and is bordered by neurovascular structures such as the optic nerve and the internal carotid artery. The reconstruction technique comprises the following main steps:

Despite significant improvements in medical therapy, surgery still has an important role in the management of pituitary adenomas and craniopharyngiomas. Further development of the endoscopic techniques will be driven by several technological advances such as high-definition intraoperative digital imaging, three-dimensional endoscopy and dedicated instruments [47, 51]. Another important determinant in improving the global outcomes of such techniques is the advancement in the anatomic research, which is of utmost importance to define the advantages and limits of skull base surgery with the endoscopic endonasal technique. At the same time, the evolution of reconstruction materials and of reconstruction techniques will greatly affect this still critical step of the procedure.