Endoscopic craniofacial resection (CFR) has emerged as an alternative to the traditional CFR originally credited to Ketcham in 1963.

The standard craniofacial approach for tumor resection combines a transfacial approach via a lateral rhinotomy or midface degloving to gain access for removal of the sinus component of the tumor with a transcranial approach to remove the skull base and intracranial portion of the tumor. The most common indications for CFR are tumors arising from the nasal cavity, frontal sinuses, or ethmoid sinuses extending to or through the anterior skull base.

The major reason for selecting endoscopic CFR is to avoid the morbidity associated with open CFR.

The rates of complication associated with open CFR as reported in the literature vary considerably.

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  In the largest study to date evaluating open CFRs, Ganly et al. reported an overall complication rate of 36.3% and a mortality rate of 4.7%.

  
  
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  The rate of CSF fistula after major CFR may be as high as 20%.

  
  
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  The rate of meningitis after CFR is reported in the literature to be 5% to 7.7%.

Despite the wide exposure afforded by the open CFR, the close proximity of the orbit, brain, and other critical neurovascular structures often prevents surgeons from taking large margins without causing significant morbidity. In fact, one multicenter study looking at outcomes of open CFRs reported a 30% incidence of positive margins.

It has been suggested that the magnified view provided by the endoscope can also make tumor mapping more precise, especially in deep areas such as the pterygopalatine fossa and sphenoid sinus, where visualization and illumination can be difficult in an open procedure. Furthermore, for some tumors, unilateral endoscopic resection is possible, thus preserving smell on the contralateral side.

A major criticism of endoscopic CFR is that the tumors are removed piecemeal. Traditional teaching is that tumors should be removed en bloc to ensure maximal survival. This principle is founded on the concept that surgical violation of the tumor predisposes to spread of the cancer through lymphatic or vascular channels, thereby increasing the risk of local, regional, and distant tumor spread. Furthermore, there is concern that tumor removal is more likely to be incomplete with a piecemeal as opposed to an en bloc resection. However, data from transoral laser microsurgery and transoral robotic surgery, as well as more recent data from endoscopic CFRs, show that this is not the case. The most important surgical variable affecting survival, regardless of the method used, is achieving complete tumor resection with negative margins.

A study comparing endoscopic versus open craniofacial resection found no significant differences in survival, metastatic rates, or complication rates between the two groups. The endoscopic group had shorter hospital stays and the added benefit of a better cosmetic outcome. However, comparison of oncologic outcomes between the groups was limited by discrepancy in histologic grade and clinical stage between the two retrospective, nonrandomized groups.

Surgery of the skull base is complex because of its proximity to the dura, brain, and orbit. Tumors will be adjacent to or involve one or more of these structures during endoscopic CFR.

Sphenoid sinus anatomy deserves special mention. The optic nerve and cavernous sinus are located along the lateral wall, whereas the sella turcica is located posteriorly and centrally.

Refer to the appropriate chapters in this text for more detailed anatomic descriptions of the sphenoid sinus, ethmoid roof, and frontal sinus.

Endoscopic CFR may be considered in the management of benign and malignant tumors of the paranasal sinuses involving the skull base.

This chapter focuses on the treatment of esthesioneuroblastoma, which is one of the more common tumors approached by this method. However, this technique can be applied to the majority of benign and malignant tumors involving the anterior skull base.

Preoperative images should be thoroughly analyzed; the findings will ultimately determine tumor resectability and critical anatomic constraints.

A multidisciplinary approach—including, when pertinent, specialists in neurosurgery, ophthalmology, medical oncology, and radiation oncology—is critical.

A definitive tissue biopsy is necessary preoperatively, especially when critical anatomic structures such as the orbit, dura, or neurovascular regions are involved.

Indications include any benign or malignant tumor of the nasal cavity and/or paranasal sinuses that involves the anterior skull base.

Contraindications include poor surgical candidacy because of comorbidities, involvement of skin or brain parenchyma, and bilateral orbital involvement.

Relative contraindications include extension into the cavernous sinus, orbit, and lacrimal system, as well as massive tumors with unfavorable histologic features. Another contraindication to the approach is the inability to reconstruct the skull base due to factors such as previous surgery, radiation exposure, or defect size.