Choice Of Surgical Approach

Surgical approaches to the sellar region can be broadly categorized into three basic groups: (1) transsphenoidal approaches, (2) conventional craniotomy, and (3) alternative skull-base approaches (Table 1). Within each of the three groups, there is one or more standard procedures, as well as a variety of technical variations and options that allow the operation to be tailored to the situation at hand. Currently, 96% of all pituitary adenomas can be approached through one or another variation of the transsphenoidal approach. The remainder require transcranial approaches, consisting of either standard pterional or subfrontal craniotomy or various skull-base approaches, which may be transcranial, extracranial, or a combination of the two.

Table 1

Surgical Approaches for Pituitary Tumors

Standard Transsphenoidal Approaches

Endonasal, submucosal, transseptal transsphenoidal approach Endonasal, submucosal, septal pushover approach Endoscopic transsphenoidal approach Standard Transcranial Approaches Pterional craniotomy Subfrontal craniotomy Subtemporal craniotomy Alternative Skull base Approaches

Cranio-orbito-zygomatic osteotomy approach

Transbasal approach of Dcerome

Extended transsphenoidal approach

Lateral rhinotomy/paranasal approaches

Sublabial transseptal approach with nasomaxillary osteotomy

Transethmoidal and extended transethmoidal approaches

Sublabial transantral approach

The surgical approach depends on a several factors. The most important of these include: (1) the size of the sella, (2) its degree of mineralization, (3) the size and pneumatization of the sphenoid sinus, (4) the position and tortuosity of the carotid arteries, (5) the presence and direction of any intracranial tumor extensions, (6) whether any uncertainty exists about the pathology of the lesion, (7) whether any previous therapy has been administered (surgery, pharmacologic, or radiotherapeutic), and (8) the surgeon's experience .

As general guidelines, a transsphenoidal approach is preferred in all but the following circumstances: (1) a tumor with significant anterior extension into the anterior cranial fossa or lateral and/or posterior extension into the middle or posterior cranial fossae, (2) a tumor with suprasellar extension and an hour-glass configuration that is constrained by a small diaphragmatic aperture, (3) when there is reason to believe that the consistency of a tumor having suprasellar extension is sufficiently fibrous to prevent its collapse and descent into the sella when resected from below, and (4) if there is doubt about the actual nature of the pathology (for example, meningioma). If any of these features is present, a transcranial procedure is preferred. It is important to recognize that these classic guidelines are less absolute today than they were in the past. The development of the extended transsphenoidal approach has now provided transsphenoidal access to several lesions that, in light of our guidelines, would have previously been considered accessible by transcranial approaches only. The spectrum of lesions accessible to transsphenoidal surgery is widening.

Occasionally the configuration of the tumor is such that a single approach, either transsphenoidal or transcranial, is insufficient to remove the tumor. This is uncommon and is typically associated with dumb-bell shaped tumors with a significant intrasellar component that has grown up through and has been narrowed by the diaphragmatic aperture. The suprasellar component in such cases may be inaccessible from below, whereas the infrasellar component may not be safely and readily accessible from above. Similarly, such bicompartimentalization occurs when an intrasellar component is associated with anterior, lateral, and retrosellar intracranial extensions into the anterior, middle, and posterior cranial fossae.

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