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Facial Translocation Approach to the Nasopharynx


Introduction

The facial translocation approach (FTA) for access to the cranial base was first described in the late 1980s by Dr. Ivo P. Janecka and colleagues at the University of Pittsburgh. The FTA was one of a number of landmark approaches described in the early days of the evolving new discipline of skull base surgery. At that time—before intraoperative imaging and image-guided navigation were widely available—most skull base approaches were based on the premise of obtaining broad anatomic exposure for the purposes of safe recognition and protection of critical skull base neurovascular structures and obtaining enough space in which to achieve complete tumor removal and repair. The FTA used the concept of modular “craniofacial disassembly” to achieve these goals. Over time, the utility, indications, and technical adaptations of the FTA have evolved, and although many other less invasive approaches have since been described, the FTA still has unique advantages in the management of certain skull base tumors, especially those involving the nasopharynx (NP) and adjacent compartments.

Historically the NP was considered a difficult anatomic target for extirpative surgery because of its central location in proximity to critical anatomy of the brain, brainstem, carotid and basilar arteries, orbits, and multiple cranial nerves. The FTA is a versatile approach (actually a system of approaches) that gives extremely broad exposure of the NP and these adjacent structures. Tumor location and pathology will guide the surgeon to tailor the most appropriate approach. A multidisciplinary discussion for surgical planning is valuable and may include Otolaryngology, Neurosurgery, Vascular surgery, and Reconstructive surgery teams, as well as Interventional Radiology and Radiation and Medical Oncologists.

Key Operative Learning Points

  • 1.

    The surgeon must have detailed knowledge of the vital structures of the NP, the face, and the adjacent compartments (infratemporal fossa [ITF], orbit, paranasal sinuses, and cranial vault).

  • 2.

    The best approach is decided upon after assessing tumor location, tumor pathology, and the surrounding structures involved. If there is intracranial extension, consultation with an experienced Neurosurgeon is essential.

  • 3.

    A thorough conceptual understanding of the sequence of steps in the FTA is essential for a safe, successful application ( Figs. 44.1–44.6 ).

    Fig. 44.1, A, Incision design for facial translocation (see text for details). B, Surgical view of zygomatic-temporal portion of the incision, with multiple frontal-temporal branches of the facial nerve identified and tagged prior to division. These nerves will be repaired at the end of the procedure.

    Fig. 44.2, Exposure of the craniofacial skeleton after reflection of the soft tissue envelope (see text for details).

    Fig. 44.3, A, Diagram of osteotomies of the orbital-zygomatico-maxillary skeleton. B, Lab dissection of medial orbit after subperiosteal exposure of the nasal-maxillary skeleton, release of the lower eyelid, showing nasolacrimal duct (pointer) prior to transection. C, Operative photo of orbito-zygomatico-maxillary segment after temporary removal; note that the infraorbital foramen has been enlarged and V2 has been released from the bone prior to explantation of the bony segment.

    Fig. 44.4, Exposure achieved after orbital-zygomatico-maxillary osteotomies and reflection of temporalis muscle from the skull, revealing the view through the infratemporal fossa toward the nasopharynx (NP). At this point, resection of the pterygoid process will provide comprehensive access to both sides of the NP.

    Fig. 44.5, A, Frontotemporal craniotomy provides additional access to intracranial compartments. For extensive nasopharyngeal tumors, this additional access will enable extirpation of tumor extensions involving the foramen ovale, the foramen spinosum, and the orbital apex, as well as drilling of the clivus if needed. B, Axial computed tomography sections of the dissected specimen showing the extent of anatomy accessible with the facial translocation approach (FTA). Top row : at the level of maxillary sinuses, before and after FTA. Bottom row : at the level of orbits, before and after FTA.

    Fig. 44.6, Temporalis muscle transposed for reconstruction of cranial base defect after facial translocation approach. A, Diagram of the flap inset. B, Magnetic resonance imaging showing transposed flap in place, reconstituting the lateral nasopharyngeal wall and isolating the cranium from aerodigestive contamination.

  • 4.

    When cranial nerves (in particular the distal branches of the trigeminal and facial nerves) must be displaced in the FTA, sharply transecting the nerves and carefully re-approximating them at the end is preferred over vigorous or prolonged stretching of the nerves and results in better functional outcomes.

  • 5.

    Orienting the horizontal incision at the level of the zygoma will protect the orbicularis oculi innervation as it enters the muscle below this level.

  • 6.

    Temporary tarsorrhaphy at the end of the surgical procedure is important to prevent scar contracture and eversion/ectropion of the lower eyelid.

  • 7.

    It is helpful to use a drill to mark the attachment point of the medial canthal tendon on the nasolacrimal bone to facilitate accurate reattachment.

  • 8.

    Transection of the coronoid process increases the mobility and reach of the temporalis muscle transposition, which can be accomplished easily as long as there is due care to avoid compromising the blood supply.

  • 9.

    When considering reconstruction, the most important concerns are closure of the dura and protection of the carotid artery.

Preoperative Period

History

  • 1.

    History of present illness

    • a.

      Ask about any neurologic deficits, emphasizing dysfunction of any cranial nerves.

      • 1)

        Dysfunction of cranial nerve V, the trigeminal nerve, is common in tumors of this area. This may present as unilateral sensory loss, facial dysesthesia, and/or mastication dysfunction (including malocclusion or deviation of the jaw).

      • 2)

        Dysfunction of cranial nerve VI is also common with tumors of the NP, where there is ready access to the cavernous sinus and the orbital apex; this is manifested by diplopia and limited lateral gaze.

      • 3)

        Dysfunction of cranial nerve VII is uncommon with nasopharyngeal tumors. However, the facial nerve will be manipulated in the FTA, and it is important to counsel patients that the innervation to the forehead will be disrupted and will require 6 to 9 months after neurorrhaphy before brow elevation function will return.

      • 4)

        Tumors from the NP may spread laterally to involve the jugular foramen and thus may result in deficits of the lower cranial nerves (IX to XII), and tumors invading the temporal bone or posterior fossa may lead to sensorineural hearing loss and vestibular dysfunction.

      • 5)

        Patients with preoperative dysphagia and aspiration should be counseled that surgery may worsen these problems, and consideration may be given to the placement of a feeding tube.

      • 6)

        Conductive hearing loss with middle ear effusion may indicate compression of the Eustachian tube (ET) by tumor mass effect.

    • b.

      Ophthalmologic history is important, including any visual losses or diplopia.

  • 2.

    Past medical history

    • a.

      Some patients being considered for FTA will have a history of nasopharyngeal carcinoma (NPC). It is important to note that primary NPC is initially treated (after confirmatory biopsy) with chemoradiation in almost all cases. Surgery is usually reserved for recurrences. FTA is reserved for extensive recurrences requiring very broad access.

    • b.

      Any history of prior head and neck surgery or radiation must be taken into consideration with regard to tissue vascularity and viability; these factors may affect the incision design and the selection of reconstructive methods.

    • c.

      The medical health and functional status of the patient are important, as surgery via the FTA may be lengthy, depending on the pathology and reconstructive needs.

    • d.

      If the patient smokes, counseling and cessation are important both for perioperative healing and long-term survival.

Physical Examination

  • 1.

    The NP must be carefully evaluated by endoscopy prior to surgical planning. Pathology in the NP can often spread to the ITF, which is relatively inaccessible to direct visualization and palpation on physical examination. However, important signs of ITF pathology can be elicited with a thorough examination of the head and neck, with special attention to the function of the cranial nerves as outlined above.

  • 2.

    Assess for trismus; this will provide information about a possible invasion into the pterygoid musculature and is essential for the preoperative planning of airway management.

  • 3.

    Evaluate visual function and document visual acuity.

  • 4.

    Obtain audiometry to document hearing status, as either conductive or sensorineural hearing loss may result from skull base lesions.

  • 5.

    Rarely, extensive tumors of the NP may involve the pituitary fossa or affect its regional blood flow, resulting in endocrine imbalance. Endocrinopathies may be variable, but the physical examination should look in particular for evidence of hypothyroidism or cortisol-related dysfunction, as these in particular may be detrimental to healing and thus cause significant perioperative complications.

Imaging

  • 1.

    With nasopharyngeal diseases, imaging plays an essential role in precise tumor location and may suggest the type of pathology. Computed tomography (CT) and magnetic resonance imaging (MRI) are complementary and both are needed. Demonstration of bony involvement and widening of the foramina is best seen on CT, while the evaluation of soft tissue planes and tumor extension along neural structures is best seen on MRI.

  • 2.

    It is critical to assess the functional status of the internal carotid artery (ICA) and its precise anatomic relationship to tumors of the NP, as this will influence details of the approach. If there is concern for ICA involvement following CT and MRI imaging, a Magnetic Resonance Angiography (MRA), computed tomography angiography (CTA), or formal angiogram should be considered. If intraoperative manipulation of the ICA is likely, the team should consider preoperative evaluation of collateral cerebral blood flow with a balloon occlusion test. Consultation with a Vascular Surgeon (or vascular neurosurgeon) may be warranted if intraoperative vascular bypass is a possibility.

  • 3.

    Evaluation of regional and distant metastatic cancer is dictated by the histology and stage of the tumor. CT/positron emission tomography (PET) scanning is warranted to detect evidence of distant metastases.

Indications

Prior to FTA, tissue biopsy with pathologic confirmation of histology is desirable, as with any major extirpative cases. Open or transnasal endoscopic biopsy is usually straightforward, but if transnasal biopsy is inconclusive, an image-guided fine-needle aspiration of the tumor beyond the NP (e.g., in the ITF) may be considered. Biopsy is not indicated for highly vascular lesions with characteristic imaging findings, such as juvenile nasopharyngeal angiofibroma (JNA).

Listed below are examples of indications for the FTA for lesions involving the NP.

  • 1.

    Extensive JNA extending through the skull base to the orbit, middle cranial fossa, and cavernous sinus, which are not amenable to purely endoscopic or less invasive approaches

  • 2.

    Carcinomas of the NP originating primarily on the lateral wall of the NP that have not responded to, or recurred after, radiation or chemoradiation

  • 3.

    Chordomas of the clivus and the surrounding structures, especially those with extension across the midline and to the craniovertebral junction

  • 4.

    Sarcomas of the NP, pterygoid, and sphenoid region

  • 5.

    Extensive transcranial lesions, such as meningiomas, nerve sheath tumors, and congenital tumors involving the NP and extending to the ITF, orbit, and cranium

  • 6.

    Minor salivary gland neoplasms of the NP or adjacent areas, with intracranial, ITF, or lateral pharyngeal extent

  • 7.

    Certain non-neoplastic disorders including complex encephaloceles, cerebrospinal fluid (CSF) leaks, and advanced infectious processes of the central skull base

Contraindications

There are no absolute contraindications to the FTA. Relative contraindications are as follows:

  • 1.

    Medical comorbidities with an increased risk for general anesthesia

  • 2.

    A failed balloon occlusion test in tumors involving the ICA raises concerns and the need for additional planning and discussions with the patient. In some cases, extracranial to intracranial bypass surgery may be an option. Some of these discussions will depend on the pathology and expected outcome.

  • 3.

    Extensive invasion of brain parenchyma by a malignant tumor is another relative contraindication. In many tumors, resection of the brain is not an acceptable treatment; however, in some cases, such as an aggressive meningioma, resection of some brain tissue may be reasonable. Multidisciplinary planning with a Neurosurgeron is needed to discuss and plan treatment options and surgical techniques in these cases.

  • 4.

    Smaller tumors often can be addressed through less invasive approaches. This is particularly true in well-defined central skull base lesions that may be amenable to an endoscopic endonasal approach. Quantitative analysis of relative advantages of different methods of access to the skull base can be helpful in selecting the best approach ; ultimately, each surgeon or surgical team must select approaches based on their own experience and results.

  • 5.

    Not all lesions are appropriate for surgical therapy. Biopsy-proven hematologic lesions such as lymphoma and plasmacytoma are best treated with nonsurgical therapy. Consideration for surgical therapy for metastatic cancer is limited to decompression.

Preoperative Preparation

  • 1.

    Both CT and MRI scans should be reviewed and available in the operating room. If any endoscopic approach is planned as an adjunct to FTA for tumor removal, image-guided navigation is recommended.

  • 2.

    Blood products should be available, especially when dealing with highly vascular lesions.

  • 3.

    Reconstructive considerations should be discussed prior to the start of the surgery and additional team members prepared to participate if necessary.

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