The Laryngoscope C 2011 The American Laryngological, V
Rhinological and Otological Society, Inc.
Endoscopic Endonasal Transpterygoid Nasopharyngectomy Salma Al-Sheibani, MD; Adam M. Zanation, MD; Ricardo L. Carrau, MD; Daniel M. Prevedello, MD; Emmanuel P. Prokopakis, MD; Nancy McLaughlin, MD; Carl H. Snyderman, MD; Amin B. Kassam, MD Objective: Describe our technique for endoscopic transpterygoid nasopharyngectomy and support its feasibility with our early clinical outcomes. Methods: Our endoscopic technique comprises an extended inferomedial maxillectomy, mobilization of the pterygopalatine fossa, removal of the pterygoid plates and Eustachian tube to access the posterolateral nasopharynx. Control of the parapharyngeal and petrous segments of the internal carotid artery is the keystone of the approach. Results: Various histopathologies were treated, including epidermoid carcinomas (n ¼ 9), lymphoepithelioma (n ¼ 1), adenoid cystic carcinoma (n ¼ 5), adenocarcinoma (n ¼ 2), mucoepidermoid carcinoma (n ¼ 2), and sarcoma (n ¼ 1). Negative microscopic margins were obtained in 95% (19/20) of patients. No perioperative mortality, cerebral spinal fluid (CSF) leak, meningitis, or cerebrovascular accident was encountered; however, one patient suffered an internal carotid artery (ICA) injury, without permanent sequelae. All but one patient received adjuvant therapy (external and/or stereotactic radiotherapy with or without chemotherapy). Follow-up ranged from 15 to 68 months (mean ¼ 33). Overall survival was 45% (9/20) and local control was 65% (13/20). Conclusions: Endoscopic transpterygoid nasopharyngectomy for primary and recurrent nasopharyngeal malignancies is feasible and safe in properly selected patients. Preliminary outcomes compare to that of conventional techniques. Endoscopic resections, however, are demanding; they require specialized equipment and a team versed in endoscopic oncologic surgery. Long-term follow-up and reproducibility remain undefined. Key Words: Cranial base, head and neck, nasopharyngectomy. Level of Evidence: 2B. Laryngoscope, 121:2081–2089, 2011
INTRODUCTION Surgery for nasopharyngeal carcinoma (NPC) is often limited to tissue sampling or to salvage select patients with residual or persistent local or recurrent regional tumor. Surgery, however, plays a primary role in the treatment of malignancies with glandular or mesenchymal differentiation.1,2 Ridge et al.3 recommended that resection of a locally discrete recurrent nasopharyngeal carcinoma should be From the Department of Otolaryngology—Head & Neck Surgery (S.A.), Al Nahdha Hospital, Oman; Department of Otolaryngology—Head & Neck Surgery (A.M.Z.), University of North Carolina–Chapel Hill, Chapel Hill, North Carolina, U.S.A; Depatment of Otolaryngology—Head & Neck Surgery ( R . L . C .), Ohio State University, Columbus, Ohio, U.S.A; Department of Neurological Surgery (D.M.P.), Ohio State University M e d i c a l C e n t e r, C o l u m b u s , O h i o , U . S . A ; D e p a r t m e n t o f Otolaryngology—Head & Neck Surgery (E.P.P.), University of Crete, Greece; Depatment of Neurosurgery ( N . M .), John Wayne Cancer Institute, Santa Monica, California, U.S.A; Department of Otolaryngology—Head & Neck Surgery (C.H.S.), University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, U.S.A; Department of Neurological Surgery (A.B.K.), University of Ottawa, Ontario, Canada. Editor’s Note: This Manuscript was accepted for publication June 17, 2011. Dr. Amin Kassam is a consultant for Storz Endoscopy Inc. and Stryker Corp. Dr. Daniel Prevedello is a consultant for Stryker Corp. All other authors have no financial disclosures for this article. The authors have no comflicts of interest to declare. Send correspondence to Dr. Ricardo L. Carrau, Director of Skull Base Surgery, The Ohio State University, Department of Otolaryngology— Head & Neck Surgery, 915 Olentangy Road, Suite 4000, Columbus, OH 43212. E-mail:
[email protected] DOI: 10.1002/lary.22165
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entertained unless the patient is unable to tolerate an operation. Others agree with this statement, and we concur, as tumors that persist or recur after primary radiotherapy have demonstrated significant resistance to this mode of therapy and are less amenable to respond to more irradiation.4–7 Similarly, we believe that surgery should be considered for patients presenting residual or recurrent tumor after radiotherapy (or chemoradiotherapy), and for patients with tumors that are considered to be poorly responsive to radiation therapy, such as adenocarcinomas, adenoid cystic carcinomas and sarcomas. Reirradiation techniques were propelled, in great part, by the difficulty and morbidity associated with the conventional resection of these tumors, as well as poor oncologic outcomes. In general, an ideal surgical approach to the nasopharynx should provide adequate visualization of the tumor margins, allow a complete oncologic resection (negative margins), allow the possibility to extend the resection margins, when needed; and allow the identification and protection of important neurovascular structures. In addition, it should avoid facial scarring or deformity, preserve the neurologic and masticatory functions, and facilitate the reconstruction of the surgical defect. Prior to the development of contemporary skull base approaches, oncologic surgery of the nasopharynx was considered near to impossible in view of the technical challenges involved with accessing this area, and the restricted working space in proximity of various critical structures. Nonetheless, despite innovations
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brought by modern skull base approaches, they still provide somewhat limited exposure and access.7,8–11 In recent years, the evolution of these approaches has incorporated endonasal endoscopic techniques to complement conventional skull base approaches, and in select cases, as the sole approach. This report provides a detailed description of our technique for endonasal endoscopic transpterygoid nasopharyngectomy for the treatment of a highly select group of patients and reviews the most important aspects of the anatomy pertaining to this area. We will provide a brief review of our outcomes to validate the feasibility and safety of this approach.
MATERIALS AND METHODS Patients We identified 20 patients who underwent an endoscopic endonasal transpterygoid nasopharyngectomy from January 2002 to January 2009, using an institutional review board (IRB)-approved database at the University of Pittsburgh Medical Center and the University of North Carolina Health Care. We included only those patients whose surgery was performed with curative intent. Patients who underwent surgery for palliative debulking, decompression or biopsies were excluded. All patients underwent a preoperative staging workup, confirming the resectability of the tumor via an endoscopic endonasal approach, assessing the status of cervical lymph nodes and excluding the presence of distant metastasis. These investigations included nasopharyngeal biopsies, contrasted computed tomography (CT) scan and/or magnetic resonance imaging (MRI) of the skull base as well as a positron emission tomography fused to a CT scan (PET/CT) to establish the absence or presence of regional and distant metastasis. Special attention was given to ascertain the relationship of the tumor to the parapharyngeal and petrous segments of the internal carotid artery (ICA). In general, tumors that surround or that extend posterior to the ICA, are not amenable to a complete resection via an endonasal endoscopic approach; therefore, the patients were not consider as adequate candidates for this approach. Although select patients may be amenable to a gross total resection, they were not included in this series. Similarly, patients with tumors that presented extensive dural involvement or extended intradurally were not considered candidates for an endonasal endoscopic approach. Important preoperative preparations included a CT angiography (CTA) used for intraoperative navigation, type and cross for packed red blood cells, administration of wide spectrum prophylactic perioperative antibiotics, and coordinating intraoperative neurophysiologic monitoring as pertinent to each case. CT and MRI fusion was also utilized in select patients. An acoustic Doppler ultrasound probe complemented the surgical navigation device for the identification of critical vessels. Our preferred prophylactic perioperative antibiotic regimen included a third generation cephalosporin with cerebral spinal fluid (CSF) penetration (or a vancomycin and gentamycin combination for penicillin-allergic patients).12 Monitoring of cranial nerves III, IV, VI, VII, IX–XII, as well as somatosensory and motor-evoked potentials was customized according to the extension of the tumor and the planned surgical resection.
Operative Technique Surgery proceeds under general endotracheal anesthesia with the patient in supine position, stabilizing the head in a
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three-pin fixation system with the neck slightly flexed, tilted to the left and turned to the right. Cottonoids soaked in oxymetazoline 0.05% or adrenaline 1/10,000–1/20,000 are inserted in the nasal cavity to provide vasoconstriction and decongestion. Infiltration of both middle turbinates and nasal septum with a solution of lidocaine 1% and epinephrine 1/100,000 enhances the hemostasis. Surgery proceeds via a purely endoscopic endonasal approach using a 0 rod lens endoscope. Endoscopes with angled lenses, such as the 30, 45, and 70 are used as needed; however, most of the surgery proceeds with the 0 . A fundamental premise of the endonasal endoscopic approach is that two surgeons work concomitantly, using a bimanual, three-/fourhanded technique via both nostrils and nasal cavities. This facilitates dynamic visualization as well as bimanual dissection, which is critical for depth perception, traction, and countertraction and for maintenance of a blood-free surgical field. Ideally, two independent video monitors are placed facing each surgeon and are vertically adjusted to accommodate the individual surgeon’s height and position. We use an optical surgical navigation system using a facemask for registration (Stryker Navigation, Kalamazoo, MI). Its camera is placed at the head of the operating table and the tracker is fixed to the three-pin fixation system taking into account the position of the surgeons and video monitors to avoid problems with the camera line of sight. Reconstruction of the surgical defect, including coverage of the middle cranial and/or posterior cranial fossae and exposed ICAs, must be planned preoperatively. The Hadad-Bassagaisteguy flap (HBF), also referred as nasoseptal flap, is our preferred technique.13,14 Given the need for a posterior septectomy and bilateral wide sphenoidotomies, harvesting of the HBF must be completed at the beginning of the surgery in order to preserve the flap’s vascular pedicle (posterior septal arteries). We harvest the HBF from the side opposite to the tumor (contralateral), as the approach usually sacrifices the maxillary artery, and therefore, interrupts the blood supply of the ipsilateral vascular pedicle. A nasomaxillary window, ipsilateral to the HBF, allows storage of the flap in the antrum during the extirpative part of the surgery. Bilateral tumor extension to the posterior nasal septum, rostrum of the sphenoid sinuses or pterygopalatine fossae precludes the use of an HBF, as the resection would sacrifice its blood supply bilaterally. Similarly, radiation induced necrosis may destroy the HBF blood supply. In such circumstances, or if the extent of the defect is larger than the potential coverage of the HBF, we reconstruct the defect with a temporoparietal fascia flap (TPFF) that is introduced into the nose via a transpterygoid tunnel.15 In our early experienced, these pedicled flaps had not been developed; thus, we free-grafted the resulting defect with an acellular dermis allograft (Alloderm, Lifecell Corp., Branchburg, NJ). Expansion of the natural nasal corridor includes an ipsilateral middle turbinectomy, anterior and posterior ethmoidectomies, a posterior nasal septectomy, bilateral wide sphenoidotomies, and removal of the floor of the sphenoid sinuses, which should be reduced posteriorly until they are ‘‘in plane’’ with the clivus. A high-speed drill with a 3- or 4-mm hybrid or coarse diamond burr (Total Performance System, Stryker Co.) is used to remove bone as needed. Intraoperative navigation confirms the adequacy of the exposure and corroborates key surgical landmarks. Exposure of the tumor requires a wide nasomaxillary window, an inferior turbinectomy, and removal of the medial maxillary wall (lateral wall of the nose) ipsilateral to the tumor. This exposes the entire posterior wall of the antrum and, after its removal, the pterygopalatine fossa (PPF) (Fig. 1). This endoscopic medial maxillectomy is limited anteriorly by the nasolacrimal duct, which becomes both the fulcrum for the rod
Al-Sheibani et al.: Endoscopic Endonasal Transpterygoid Nasopharyngectomy
Fig. 1. To the left, schematic representation of endoscopic endonasal approach showing the posterior wall of the antrum. To the right, intraoperative endoscopic photograph after a right endoscopic medial maxillectomy and extended sphenoidotomy demonstrating: posterior wall of the antrum (PAW), ascending process of the palatine bone (APPB), torus tubarius (TT), and lateral recess of the sphenoid sinus (LRSS).
lens endoscope and an impediment to move the scope laterally.16 An endoscopic Denker’s approach eliminates this obstacle by removing the most anterior aspect of the medial maxilla including the piriform aperture. Removal of the medial aspect of the anterior wall of the maxilla widens the lateral angle of exposure and increases the space for the maneuvering of the instruments (Fig. 2). It should be noted, however, that a Denker’s extension of the medial maxillectomy is not always required. In some patients the geometry and pneumatization of the maxillary sinus and nasal cavities, or the extension of the tumor, are such that the most lateral oncologic margins can be controlled without removing the bone of the piriform aperture. Additional lateral control is also obtained by maneuvering the instruments from the contralateral side (‘‘cross court’’), which increases the lateral angle of approach.16 To complete the endoscopic Denker’s approach, we vertically incise the mucosa over the edge of the piriform aperture (just anterior to the anterior head of the inferior turbinate) (Fig. 3a). This incision is carried through the submucosa and periosteum so that the anterior aspect of the maxilla is exposed following a subperiosteal dissection (Fig. 3b). The most anterior aspect of the medial maxillary wall (i.e., lateral wall of the inferior meatus and head of inferior turbinate) is removed using back biting rongeurs or a high-speed drill. In select patients, we can spare the lacrimal opening, resecting just the area beneath. If the distal lacrimal apparatus must be removed, the surrounding bone is drilled away and the nasolacrimal duct is divided sharply. A dacryocystorhinostomy is not needed. Bone removal is extended further anterior to remove the bone comprising the piriform aperture and laterally to remove the anterior wall of the antrum. These steps create a single cavity that connects the nasal cavity, antrum, ethmoid, and sphenoid sinuses and nasopharynx (Fig. 3a and b). Localization of the sphenopalatine foramen (or foramina), just posterior to the upper third of the posterior wall of the antrum, helps to identify and control the sphenopalatine and posterior nasal arteries (Fig. 4). The posterior wall of the antrum is removed using 1- to 2-mm Kerrison rongeurs to a point just lateral to the inferior orbital fissure. It should be noted that the inferior orbital fissure is continuous with the pterygomaxillary fissure and is the boundary between the infratemporal and pterygopalatine fossae; therefore, exposure of the infraorbital fissure guarantees access to the entire PPF and exposes the medial infratemporal fossa.
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The sphenopalatine and posterior nasal arteries are cauterized using an endoscopic bipolar electrocautery and are subsequently divided and mobilized laterally. The vidian foramen and its neurovascular bundle is then exposed, coagulated, and divided, allowing the lateralization of soft tissue within the PPF.17,18 A subperiosteal dissection of this soft tissue from the pterygoid plates avoids bleeding from the venous and arterial plexus within the PPF and facilitates the identification the foramen rotundum and the maxillary branch of the trigeminal nerve (Fig. 5). The descending palatine nerve and greater palatine artery descend in front of the pterygoid plates and may also tether the lateralization of the soft tissues of the PPF (Fig. 4). If the entire pterygoid process needs to be removed, this neurovascular bundle is usually sacrificed, thus resulting in numbness of the ipsilateral hard palate. The vidian and V2 canals are dissected, removing the bone that separates these two structures in an anterior to posterior fashion. These three landmarks, the vidian and V2 canals, as well as the wedge-shape bone in between, respectively reach the
Fig. 2. To the left, we show a photograph of the maxillofacial skeleton with a diagrammatic representation of the potential extent of the anterior maxillotomy as marked by the broken line (part of the Denker’s approach). To the right, MRI showing the extent of a pure transnasal resection using a 0 rod lens endoscope (dotted line) and the enhanced lateral extent afforded with a Denker’s extended medial maxillectomy (broken line).
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Fig. 3. Intraoperative photographs of a left Denker’s approach: (a) incision; subperiosteal dissection over the anterior wall of the maxilla (AWM). Arrows mark the bony edge of the piriform aperture. (b) Extent of the Denker’s maxillotomy (broken line). (c) Unencumbered view of the lateral wall of the antrum (LWA). petrous ICA, the gasserian ganglion (Meckel’s cave), and paraclival ICA.17 Drilling of the vidian canal must proceed along its inferior hemicircumference, as this better avoids inadvertent injury to the ICA (Fig. 6).19,20 Once the lacerum segment of the ICA is identified, the bone over its petrous horizontal segment is removed laterally. The mandibular branch of the trigeminal nerve (V3) is identified anterior to the petrous ICA and under V2. If a more distal control of the ICA is necessary, the bony canal over the paraclival carotid (vertical segment) is drilled also. Injury to the vessel is avoided by the use of a high-speed drill equipped with a hybrid burr (or coarse diamond) to thin its bony canal. This type of burr is less likely to injure the ICA, upon light contact, than a cutting burr and does not produce as
much thermal injury as a diamond burr. The bony canal should be drilled until eggshell thin, and is then fractured and dissected from the vessel. The fibrocartilaginous tissue filling the foramen lacerum can be very tenacious and often requires sharp dissection. Dissection of the tumor along the ICA is performed with great care, confirming the position and trajectory of the vessel with both the intraoperative navigation and acoustic Doppler sonography. The medial pterygoid plate is removed to expose the cartilaginous medial third of the Eustachian tube (Fig. 7). Whenever possible the lateral pterygoid plate is preserved as it serves as a landmark to mark the position of the parapharyngeal ICA (Fig. 8). The medial Eustachian tube is transected and removed to expose the entire fossa of Rosenmuller and the tumor within (Fig. 9). The
Fig. 4. To the left, schematic representation of endoscopic endonasal approach after removal of the posterior wall of the antrum showing the internal maxillary artery (IMA) in the pterygopalatine fossa (PPF). To the right, intraoperative endoscopic photograph after a removal of the medial aspect of the posterior wall of the antrum (PAW) exposing: palatine neurovascular bundle (PNB) in the descending palatine canal, pterygopalatine fossa (PPF), and sphenopalatine foramen (SPF). The mucoperiosteum of the lateral wall of the posterior choana has been elevated to expose the medial aspect of the medial pterygoid plate (MPP). The Eustachian tube (ET) penetrates the nasopharynx just posterior to the medial pterygoid plate.
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Al-Sheibani et al.: Endoscopic Endonasal Transpterygoid Nasopharyngectomy
Fig. 5. To the left, schematic representation of endoscopic endonasal approach after mobilization, or removal, of the soft tissues within the pterygopalatine fossa (PPF); thus, exposing the pterygoid process (PtP). To the right, intraoperative endoscopic photograph after subperiosteal and lateral mobilization of the soft tissues of the pterygopalatine fossa (PPF) exposing: base of the pterygoid process (BPP), the vidian foramen (VF), and the foramen rotundum (FR). tumor is removed en bloc or in sequential layers according to its relationship to critical neurovascular structures. Adequacy of the resection is corroborated with intraoperative histologic analysis (‘‘frozen sections’’). In general, the surgical resection should continue until the tissue margins are clear of tumor or until further resection is not possible due to invasion of critical structures. Conversion to an open approach may be necessary if the tumor extends to areas that, although resectable, cannot be extirpated through the endoscopic approach. After histologic confirmation that the surgical margins are tumor-free, the defect is reconstructed with an HBF or temporoparietal fascia flap, covering any exposed dura and/or ICA. The vascularized flap is fixed in place using oxidized cellulose and gelatin sponges and Duraseal (Covidien, Waltham, MA), fibrin glue, or platelet rich serum. Silicone nasal splints are sutured to the remaining anterior septum to prevent synechiae. The donor site defect for the nasoseptal flap can be relined using a mucoperiosteum free graft from the sacrificed
Fig. 6. Intraoperative photograph of the left vidian foramen and nerve (VN) with a schematic representation to emphasize the need for a dissection in the inferior hemicircumference (3–9 o’clock in the left side). VICA ¼ vertical internal carotid artery canal; FR ¼ foramen rotundum.
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middle turbinate or using a reverse mucoperiosteal flap from the contralateral side of the septum (Caicedo’s reverse flap).21
RESULTS Our study cohort comprises 20 patients including 12 men (60%) and 8 women (40%) with a mean age of 52 years (range: 36–63 6 10.6 years). Nine patients had squamous cell carcinomas, one had a recurrent lymphoepithelioma, five had adenoid cystic carcinomas, two had adenocarcinomas (one low and the other intermediate grade), two had mucoepidermoid carcinomas, and one had a follicular dendritic cell sarcoma. Ten patients had not received any prior therapy. Seven of these ten patients had stage IV tumors and three had stage III. Ten patients presented recurrent or persistent tumors. Five of these 10 patients with recurrent tumors had stage III tumors, and 5 had stage IV (1997 AJCC staging system). Only one patient, with a recurrent lymphoepithelioma, presented with cervical metastases, thus requiring a neck dissection as part of the surgical treatment. All surgeries were performed via endonasal endoscopic route with the intention to cure. Negative microscopic margins were obtained in 95% (19/20) of cases. One patient with SCCA had a microscopically positive margin on the ICA’s lacerum segment. We deemed that invasion of the vessel wall over this area was not amenable to a safe surgical clearance, endoscopic or open (we had decided not to sacrifice the ICA preoperatively). This patient underwent postoperative chemoradiotherapy and after 22 months of followup still shows no evidence of disease (NED) on examination and serial imaging. In this series, we did not have to convert the endoscopic approach to a traditional open procedure in any of the patients. We encountered no perioperative mortality, cerebrovascular accident, postoperative CSF leak, postoperative epistaxis, or infectious complications. One patient with a stage IV mucoepidermoid carcinoma suffered an ICA injury resulting in significant intraoperative hemorrhage, which was controlled endoscopically (using
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Fig. 7. To the left, schematic representation of an endoscopic endonasal approach after dissecting the medial and lateral pterygoid muscles (MPM and LPM, respectively) and removing the pterygoid process to gain access to the cartilaginous Eustachian tube (cET) and dissect the vidian nerve (VN). To the right, intraoperative endoscopic photograph after removal of the base of the pterygoid process and medial pterygoid plate exposing: remnants of the lateral pterygoid plate (LPP), pterygopalatine fossa (PPF), vidian nerve (VN). TM ¼ temporalis muscle; TT ¼ torus tubarius; LRSS ¼ lateral recess of the sphenoid sinus; FOA ¼ floor of the antrum; FON ¼ floor of the nose.
aneurysm clips) before transferring the patient to the interventional radiology suite for ultimate management. Cerebral angiography demonstrated that the ICA had been adequately controlled with aneurysm clips; thus, only the proximal ICA had to be coiled endovascularly. This patient recovered uneventfully. The median blood loss in this study population was 225 mL (range: 100–4,000 mL). Postoperatively, 10 patients received intensity modulated radiation therapy with or without chemotherapy. Another nine patients, all with recurrent tumors following chemoradiotherapy, underwent stereotactic radiation therapy (Cyberknife; Accuray Inc., Sunnyvale, CA) with or without adjuvant chemotherapy. One remaining patient with a low-grade mucoepidermoid carcinoma was treated with surgery alone.
The follow-up period ranged from 15 to 68 months (mean ¼ 33.6 6 17 months; median ¼ 30 months). The overall and disease-free survival was 45% and actuarial local control was 65%. Five of nine patients (55%) with squmaous cell carcinoma associated antigen (SCCA), the only patient with lymphoepithelioma, one of two patients (50%) with mucoepidermoid carcinoma, one of two patients (50%) with adenocarcinoma, and one of five patients (20%) with adenoid cystic carcinoma were dead of disease (DOD) at the time of our analysis. Four patients with squamous cell carcinoma and one patient with adenoid cystic carcinoma died with local disease. Another patient with recurrent lymphoepithelioma died of a common carotid artery blowout due to regional recurrence. One patient with mucoepidermoid carcinoma was NED locoregionally but succumbed to distant metastasis 3 years after treatment. In addition, one patient with adenocarcinoma, but deemed to be NED, died of a carotid blowout 5 years after treatment due to clival osteoradionecrosis. One patient with recurrent squamous cell carcinoma, who had been rendered NED after surgery and stereotactic radiotherapy, suffered a sudden death 15 months after treatment. During the study follow-up period ranging from 15 to 68 months (mean ¼ 33.6 6 17 months; median ¼ 30 months) the overall and disease-free survival was 45% and actuarial local control was 65%.
DISCUSSION
Fig. 8. Basal view of the skull base demonstrating the relationship (arrow) of the lateral pterygoid plate (a), foramen ovale/V3 (b), and the carotid canal/parapharyngeal ICA (c). These structures are in alignment from the endoscopic perspective (discounting the possible tortuosity of the ICA); therefore, the lateral pterygoid plate and V3 (as well as the ET) ‘‘guard’’ the ICA.
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Primary nasopharyngeal carcinomas are usually treated with radiotherapy or chemoradiotherapy. Surgery has a limited role, providing tissue samples or alleviating compressive symptoms. The recurrence rate of nasopharyngeal carcinoma at 5 years following modern radiotherapy ranges from 19 to 56% depending on the initial stage of presentation.22,23 The management of patients with recurrent tumors is fraught with difficulties and their prognosis is guarded. Regardless of the histopathology, reirradiation has the potential for severe complications, such as brain necrosis, hearing loss, soft
Al-Sheibani et al.: Endoscopic Endonasal Transpterygoid Nasopharyngectomy
Fig. 9. To the left, schematic representation of an endoscopic endonasal approach after lateral mobilization or partial removal of the medial and lateral pterygoid muscles (MPM and LPM, respectively) to further expose infratemporal fossa and identify the cartilaginous Eustachian tube (cET), V3, and the parapharyngeal internal carotid artery (ppICA). To the right, intraoperative endoscopic photograph after removal of the cartilaginous Eustachian tube (cET) and tumor within the fossa of Rosenmuller exposing the preverteral muscles (PVM). Lt TT ¼ left torus tubarius; RtSS ¼ right sphenoid sinus; LtSS ¼ left sphenoid sinus; SP ¼ soft palate; ET ¼ stump of the Eustachian tube.
tissue necrosis, osteoradionecrosis, cranial neuropathies, and severe trismus.24 In addition, survival rates after reirradiation range from 26 to 57% for patients with rT1 and rT2 tumors and from 4 to 42% for patients with recurrent T3 and T4 lesions.5,25–28 In the setting of persistent or recurrent locoregional disease, some evidence supports that surgery may play a significant role in the management of such patients.3–7 Surgery, however, is one option among a variety of modern reirradiation schemes including stereotactic, brachytherapy, proton, or intensity modulated therapy.24–27,29–33 In contrast, malignancies with glandular differentiation such as adenocarcinoma, adenoid cystic carcinoma, or those with a dual origin such as mucoepidermoid carcinoma are more resistant to radiation therapy. Therefore, surgery plays a greater role in their initial management. Similarly, a surgical resection is critical for the treatment of sarcomas for which a cure is often dependent on the completeness of their resection. Nasopharyngectomy is a challenging operation, and even with the use of modern skull base approaches, it is associated with significant morbidity. In addition, the open surgical approaches often offer limited exposure to one or more subsites of the nasopharynx, thus often requiring combined approaches. Traditional skull base approaches may also be combined with endoscopic techniques in various forms of endoscopic assisted nasopharyngectomy. Others have reported various endoscopic endonasal techniques for nasopharyngectomy; however, these have been confined to the treatment of small tumors amenable to resection through a simple nasal corridor (stages I and II).3834,35 In 2005, Yoshizaki and colleagues24 reported a transnasal approach that included a posterior septectomy using an endoscopic holder to allow the surgeon to operate using a bimanual technique. They reconstructed the surgical defect with a free skin graft. In 2007, Chen et al.34 performed a similar approach but Laryngoscope 121: October 2011
advocated covering the wound surface using a free mucosal graft harvested from the inferior turbinate. The exposure afforded by these approaches is limited, as any lateral extension would escape the direct vision of the surgeon; therefore, they preclude resecting any tumor that invades the petrous skull base or extends laterally to the apex of the fossa of Rosenmuller. Our technique differs significantly from these previously published endoscopic techniques.28,34,35 We advocate a two-surgeon four-hands technique that allows dynamic visualization and bimanual dissection. Combining a medial maxillectomy supplemented by an endoscopic Denker’s approach greatly facilitates the removal of the posterior and lateral walls of the antrum, mobilization of the soft tissue contents of the pterygopalatine fossa and removal of the pterygoid process and cartilaginous Eustachian tube to access the fossa of Rosenmuller and infratemporal fossa. This approach allows control of the parapharyngeal and petrous segments of the ICA, which is critical to safely and completely resect tumor extending into the fossa of Rosenmuller and the infratemporal fossa (Fig. 10). In our series we treated a highly select group of patients with advanced primary and recurrent nasopharyngeal tumors using a purely endoscopic approach. Adequate patient selection is critical to avoid having to convert to an open approach. Encasement of the parapharyngeal ICA or extension of the tumor posterior to the ICA (parapharyngeal or petrous segments) is considered contraindications to an endonasal endoscopic resection with curative intent. Such tumors are better removed via open surgical approaches such as the preauricular or postauricular subtemporal approaches.34 Importantly, we encountered in this series two patients who suffered an ICA blowout. Both were related to osteoradionecrosis of the clivus and occurred 3 and 56 months after treatment (i.e., endoscopic surgery followed
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Fig. 10. (A) Preoperative axial MR image of a patient with a recurrent squamous cell carcinoma (rT3N0M0). The tumor was completely excised with confirmed histologic negative margins). (B) Postoperative axial MR image 2 years after resection and stereotactic radiation.
by chemoradiotherapy). These events were not directly or temporally associated with the nasopharyngectomy. A surgical consideration, however, is that the ICA blowout occurred in patients reconstructed with free tissue grafts. Reconstruction with a vascularized nasoseptal or a temporoparietal fascia pedicle flap facilitates the healing of the defect, resists irradiation, and protects the ICA against exposure and blowout. As illustrated, this catastrophic complication may even occur years after treatment. Another patient with a regional recurrence suffered a blowout of the left ICA 15 months after treatment. This patient suffered a subsequent cardiac arrest and died 2 days after endovascular sacrifice of the affected vessel. The actuarial local control rate in our series was 65% at a mean follow-up of 33 months. This compares with the outcomes after conventional open skull base approaches but also emphasizes the aggressive biologic behavior of malignant tumors arising in the nasopharynx. In select patients, our endoscopic endonasal approach meets most of the requirements of an ideal surgical approach. It provides excellent surgical access with good visualization and appropriate control of neurovascular structures, optimal oncologic resection with negative margins, no facial scarring, and maximum preservation of function. Our series, albeit small, suggests the potential effectiveness of this approach in the management of advanced nasopharyngeal tumors. Use of this approach as part of a treatment protocol for nasopharyngeal tumors deserves further study. It should be noted, however, that its indications and use are limited not only by comorbidities and the extent of the disease but also by the required expertise and resources.
CONCLUSIONS Endoscopic endonasal transpterygoid nasopharyngectomy is a feasible approach for the surgical treatment of selected primary and recurrent nasopharyngeal tumors. The surgical technique is associated with a relaLaryngoscope 121: October 2011
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tively low morbidity but it is demanding and requires a very experienced team and specialized equipment. Preliminary outcomes show promise, with local control that compares to those of conventional techniques. Our patient series, however, is small, and the cohort highly selected. In addition, outcomes at longer follow-up and reproducibility are still undefined.
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