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| Skull
Base Surgery |
| Transfacial
Approaches |
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Earlier procedures of transfacial exposure of the lateral compartment
of the middle cranial base resulted in high morbidity and mortality,
largely because adequate methods to reconstruct major cranial base
defects were not available. With the subsequent introduction of craniofacial
disassembly techniques and vascularised reconstructive flaps, it has
become possible in recent years to dismantle the facial skeleton,
to extirpate deep-seated lesions, and to perform functional reconstruction
to an extent not previously possible.
A transfacial approach to this region is desirable
because it eliminates the viscerocranial skeleton as an obstacle
to exposure, thus 'opening up' not only the entire infratemporal
fossa but also the nasal cavity, nasopharynx, pterygopalatine fossa
and sphenoid region to direct access all at once.
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| The
facial translocation approach (Janecka) involves temporary removal
of orbito-zygomatico-maxillary skeletal segment to expose the infratemporal
fossa, nasopharynx, sphenoid sinus and clivus. Low temporal craniotomy
can be done if there is intracranial extension. After tumour removal,
the free orbito-zygomatico-maxillary bone is fixed with mini plates. |
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| The
other transfacial approach found very useful is the Extended osteoplastic
maxillotomy approach. The maxillofacial skeleton is partly exposed
through an incision as in facial translocation approach. Osteotomies
made at specific sites enable disengagement of the maxilla from
the facial skeleton. The maxilla is mobilized along with the skin
and soft tissues of the ipsilateral cheek, maintaining its vascularity.
Concurrent use of a temporal craniotomy provides corresponding access
to the cranial cavity. Miniplate fixation of the maxilla and zygoma
re-establishes skeletal contour. The exposure is similar to the
facial translocation approach.
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The most extensive type of subcranial approach, Extended transfacial
subcranial approach includes resection of both maxilla and mandible.
The exposure of the subcranial floor of both the anterior and middle
fossa afforded by this approach is extensive. The extent of partial
mandibulectomy and maxillectomy varies with the extent of the tumour.
The standard type of craniotomy can still be done in addition if large
lesions with wide-field intracranial spread are inadequately exposed
by using this approach. |
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