Endoscopic Transnasal Approach to the Pterygopalatine Fossa

ORIGINAL ARTICLE Endoscopic Transnasal Approach to the Pterygopalatine Fossa

John M. DelGaudio, MD

Objective: To describe an endoscopic transnasal ap- through the same approach with further lateral expo- proach to the pterygopalatine fossa (PPF). sure to the area of the inferior orbital fissure.

Design: Case series of 3 patients. Results: All patients had successful endoscopic approaches for tumor removal (case 1) and biopsy (cases Setting: An academic medical center. 2 and 3) of the PPF. The second patient had a repeat endoscopic biopsy 1 week later to obtain more tissue for Patients: One patient presented with an asymptomatic diagnostic purposes. None of the patients had any ma- PPF schwannoma. The second patient presented after a jor vascular complications. At follow-up, 2 of 3 patients sudden onset of complete unilateral vision loss with a com- had persistent sensory deficits. plete ipsilateral sphenoid sinus opacification and radio- graphic signal abnormality in the PPF and inferior orbital fissure. The third patient had a history of adenoid Conclusions: The endoscopic transnasal approach to the cystic carcinoma of the lacrimal gland, and was found PPF is a safe and effective method for biopsy and re- to have new-onset facial numbness. moval of PPF masses. The endoscopic approach im- proves access and visualization, and has the potential to Intervention: One patient had a complete excision of reduce complications compared with open approaches. a schwannoma by means of an endoscopic transnasal ap- Image guidance is helpful in these cases. proach. The other 2 patients had wide exposure and biopsies of the PPF. One patient had a revision procedure Arch Otolaryngol Head Neck Surg. 2003;129:441-446

NDOSCOPIC SURGERY has ery periods when compared with stan- gained universal accep- dard open approaches. tance as the surgical The pterygopalatine fossa (PPF) is a method of choice for the difficult-to-access anatomic area. It is lo- treatment of inflammatory cated behind the posterior wall of the max- sinonasalE disease. With increasing famil- illary sinus, bordered by the pterygoid iarity with endoscopic techniques, plates posteriorly and the greater sphe- increased understanding of sinus and noid wing and middle cranial fossa supe- perisinus anatomy, and advanced tech- riorly. It has connections with the infra- nology in the form of instrumentation temporal fossa laterally through the and image-guided systems, there has pterygomaxillary fissure, the posterior na- been a natural extension of these tech- sal cavity medially through the spheno- niques to include treatment of other dis- palatine foramen, the orbit superiorly ease processes. These include endoscopic through the inferior orbital fissure, and the treatment of sinus and skull base palate inferiorly through the palatine fo- tumors,1-3 repair of cerebrospinal fluid ramina. Structures contained within the leaks and meningoencephaloceles,4,5 PPF include the internal maxillary artery orbital decompression,6,7 approaches to and its branches, the maxillary division of From the Department of the orbital apex and clivus,8,9 transsphe- the trigeminal nerve (V ), and the vidian Otolaryngology–Head and 2 noidal approaches to the pituitary,10 and nerve. Tumors of the PPF are uncom- Neck Surgery, Emory 11,12 University School of Medicine, arterial ligations for epistaxis. These mon, with the most common being nerve Atlanta, Ga. Dr DelGaudio has approaches allow good visualization sheath tumors. no relevant financial interest in of difficult-to-access locations with Standard approaches to the PPF re- this article. decreased morbidity and shorter recov- quire transmaxillary techniques that vio-

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©2003 American Medical Association. All rights reserved. Downloaded From: https://jamanetwork.com/ on 09/30/2021 Figure 1. Case 1. Coronal computed tomographic scan of the sinuses shows a schwannoma in the right pterygopalatine fossa (thin arrow). The left pterygopalatine fossa is normal (thick arrow).

Figure 2. Case 1. Axial magnetic resonance image shows a late the anterior and posterior walls of the maxillary si- well-circumscribed mass in the right pterygopalatine fossa causing anterior nus, with the risks of facial edema and pain, infraorbital displacement of the posterior wall of the maxillary sinus. nerve injury, oroantral fistula, chronic maxillary sinusitis, and vascular injury. An endoscopic approach to the PPF can potentially reduce these risks, along with pro- Caldwell-Luc operation if necessary. The patient was viding better visualization than headlight- or microscope- counseled regarding the risk of vascular injury to the in- directed approaches. Herein we report an endoscopic ap- ternal maxillary artery and the possible need to convert proach to the PPF for definitive resection of a schwannoma to an open approach. in 1 patient and for biopsy of the PPF in 2 other pa- The procedure was begun with a large maxillary an- tients. trostomy, ethmoidectomy, and wide sphenoidotomy to expose the medial and anterior aspects of the tumor REPORT OF CASES (Figure 3). The mucosa of the posterior maxillary sinus was elevated from superomedial to inferolateral. The CASE 1 thinned posterior wall of the maxillary sinus was easily removed from the anterior and superior surfaces of the A 33-year-old woman was referred for evaluation of a right PPF mass to expose the capsule. The sphenopalatine ar- PPF mass identified on sinus computed tomographic (CT) tery was dissected from the surface and medial aspect of scan ordered for evaluation of recurrent nasal conges- the mass, cauterized, and transected medially to com- tion. The CT scan showed a well-circumscribed PPF mass pletely free the medial aspect of the tumor. The tumor that had thinned and anteriorly displaced the posterior was then bluntly dissected off of the pterygoid plates pos- wall of the maxillary sinus (Figure 1). Magnetic reso- teriorly. Because of the tight confines of the PPF and the nance imaging showed the mass to be well circum- dense inferior attachments of the tumor to the vascula- scribed and isointense with brain on T2 images, to en- ture of the PPF, the tumor could not be removed en bloc. hance with gadolinium, and to have a slightly The capsule was therefore opened to allow complete re- heterogeneous appearance (Figure 2). The patient de- moval of the tumor. The inferior portion of the tumor nied facial paresthesia or pain, and results of neurologic was removed last, after identification and clipping of the examination were normal. Endoscopic examination main trunk and branches of the internal maxillary ar- showed only fullness in the lateral nasal wall adjacent to tery (Figure 4). After confirmation of complete tumor the posterior attachment of the right middle turbinate. removal and irrigation of the PPF, the surgical area with The mass was presumed to be a nerve sheath tumor on exposed pterygoid periosteum was covered with a dis- the basis of the clinical and radiologic data. solvable hyaluronic acid pack. An endoscopic transnasal approach for resection of Postoperatively the patient was observed overnight the mass was recommended to the patient. Consent was and discharged the following morning. She did develop also obtained for a canine fossa approach and possible numbness in the distribution of the maxillary division

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Figure 5. Case 2. Axial computed tomographic scan shows asymmetry of Figure 3. Endoscopic view of pterygopalatine fossa schwannoma (T) before the pterygopalatine fossa, with the right side showing loss of normal removal of overlying thinned bone of maxillary sinus. MT indicates middle soft-tissue architecture (thin arrow) compared with the left (thick arrow). turbinate; S, sphenoid sinus; and asterisk, suction cannula. Sphenoid sinus (asterisk) is opacified with a heterogeneous appearance suggestive of fungal contents.

PP S IMA N

M IT Figure 6. Case 2. Coronal magnetic resonance image shows normal tissue signal of the left pterygopalatine fossa (black arrow) and orbital apex (thick Figure 4. Endoscopic view of pterygopalatine fossa. The internal maxillary white arrow), but the right pterygopalatine fossa and orbital apex tissues artery (IMA) is isolated and the sphenopalatine artery (arrow) has been show loss of normal tissue signal (thin white arrows). S indicates sphenoid clipped. A nerve (N) is seen exiting from the final piece of tumor (asterisk) sinus. located behind the IMA. MT indicates middle turbinate; IT, inferior turbinate; PP, pterygoid plates; and M, posterior wall of maxillary sinus. were normal. No other cranial nerve abnormalities were identified. of V2 that minimally improved during the next 12 A CT scan of the sinuses disclosed right sphenoid months. Follow-up CT scan and serial evaluations opacification with hyperostosis of the sinus walls. The showed no evidence of recurrence 6 months postopera- sphenoid contents had a heterogeneous appearance. There tively. was no extension outside of the sinus, and the remain- der of the sinuses was clear. No bone erosion was pres- CASE 2 ent. There was a subtle asymmetry of the soft-tissue char- acteristics in the right PPF (Figure 5). Magnetic A 44-year-old woman was referred for evaluation 6 resonance imaging demonstrated the same asymmetry in weeks after developing complete vision loss in the right the PPF. The soft tissue in the right PPF displayed loss eye that occurred during 36 hours. Her vision did not of normal enhancement, and this extended to the infe- respond to high-dose oral and intravenous corticoste- rior orbital fissure and the orbital apex. No discrete mass roids. Ophthalmologic examination showed only mini- was identified (Figure 6). The radiologic appearance mal light perception in the right eye and no other and clinical history were suggestive of an infiltrative pro- abnormalities. Results of otolaryngologic examination cess in the PPF.

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PPF

SP MT M

Figure 8. Case 2. Endoscopic view of healed sinonasal cavity 6 weeks after Figure 7. Case 2. Endoscopic view of wide opening into the pterygopalatine procedure. PPF indicates pterygopalatine fossa; S, sphenoid sinus; fossa (arrows depict borders of bony opening through the posterior M, maxillary sinus; and MT, middle turbinate. maxillary sinus). S indicates sphenoid sinus; SP, sphenopalatine vascular bundle; and M, posterior wall of maxillary sinus.

The patient underwent endoscopic ethmoidectomy CASE 3 and a large sphenoidotomy with removal of fungal debris (cultures yielded Aspergillus flavus). The PPF was then ad- A 67-year-old man with a history of adenoid cystic car- dressed by creating a large maxillary antrostomy with re- cinoma of the lacrimal gland more than 5 years earlier, moval of the medial wall of the sinus to the junction with treated by orbital exenteration and postoperative radia- the posterior wall. Further elevation of the mucosa over tion therapy, was referred for evaluation of sinusitis and the lateral nasal wall allowed identification of the sphe- a concern of possible recurrence of his cancer. A CT scan nopalatine vascular pedicle exiting the sphenopalatine fo- of the sinuses had been obtained and showed left eth- ramen, and dissection was continued superior to this to moid soft-tissue thickening and some thickening of the avoid vascular injury. The mucosa of the posterior max- PPF. On examination, the patient was noted to have de- illary sinus was elevated from medial to lateral. A curved creased sensation of the cheek skin. Results of endo- probe was used to palpate the sphenopalatine foramen (be- scopic examination were consistent with acute sinus- tween the posterior wall of the maxillary sinus and the body itis. Biopsy specimens of the orbital cavity were negative of the sphenoid bone), and the upper portion of the pos- for tumor. The patient was treated with antibiotics for terior wall of the maxillary sinus was removed with cu- the sinusitis. A magnetic resonance image showed en- rettes and rongeurs to expose the PPF. No discrete mass hancement and thickening of V2 in the PPF, infraorbital was found, and biopsy specimens of the PPF soft tissue fissure, and cavernous sinus (Figure 9). showed scattered salivary tissue on frozen section. Final The patient underwent an endoscopic approach to the pathological examination showed no tumor or disease pro- PPF with the use of an image-guided surgery system (Land- cess. The patient was returned to the operating room 1 week marX; Medtronic Xomed, Inc, Jacksonville, Fla). A wide later for additional biopsies. The PPF was accessed through maxillary antrostomy and total ethmoidectomy were per- the same approach and opened up further laterally to the formed. A sphenoidotomy was performed to define the po- level of the inferior orbital fissure, as identified with the sition of the face of the sphenoid sinus and the body of the image-guided system (Figure 7). Branches of the max- sphenoid bone lateral to this. The horizontal portion of the illary division of V2 were visualized and biopsy speci- basal lamella was taken down to identify the sphenopala- mens were taken from the PPF, including a small speci- tine vasculature as it exits the sphenopalatine foramen. The men of a medial branch of the nerve. The mucosa of the mucosa was elevated from medial to lateral off of the pos- posterior wall of the maxillary sinus was replaced over the terior wall of the maxillary sinus. Because of the thickness bony defect into the PPF. of the bone overlying the PPF, a drill was used to remove The patient developed some mild hypesthesia of the the bone from medial to lateral with the sphenopalatine vas- nasolabial fold postoperatively. Final pathological ex- culature and foramen used as a guide. This allowed wide amination showed no abnormal tissue. The patient did exposure of the PPF (Figure 10). Biopsy specimens of not regain any vision in the right eye, and the definitive the PPF were taken superiorly to avoid the vasculature. Fro- cause of her vision loss was not determined. The surgi- zen section analysis was positive for adenoid cystic carci- cal site healed well, with remucosalization of the PPF and noma. The mucosa of the maxillary sinus was redraped over widely patent sinuses (Figure 8). the exposed PPF.

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Figure 9. Case 3. Magnetic resonance image shows enhancement and Figure 10. Case 3. Endoscopic view of wide opening into the pterygopalatine thickening of the maxillary division of the trigeminal nerve in the fossa (arrows depict borders of bony opening through the posterior pterygopalatine fossa (black arrow) and cavernous sinus (white arrow). maxillary sinus). M indicates reflected maxillary sinus mucosa; S, sphenoid sinus; asterisk, area of pterygopalatine fossa biopsies below the inferior orbital fissure; and number sign, sphenopalatine vascular bundle. COMMENT The PPF is a small area that is difficult to access. Fortu- cal approach with further lateral extension that allowed nately, tumors of this area are rare. When the PPF needs exposure all the way to the inferior orbital fissure. A re- to be addressed, the standard procedure is through a cent report of 4 cases of transnasal endoscopic biopsy of Caldwell-Luc approach, violating the anterior and pos- PPF masses also confirms the safety of this procedure.16 terior walls of the maxillary sinus and exposing the PPF At least 2 of the patients described in that series appeared for microscopic or headlight evaluation. This is the to actually have infratemporal fossa tumors rather than PPF method commonly used for internal maxillary artery li- tumors, as depicted in their photographs. The authors de- gation.13 This method provides limited exposure with the scribe approaching the tumor directly through the poste- possibility of neural and vascular injury. It can also re- rior wall of the maxillary sinus, which may be better for sult in irreversible changes in the maxillary sinus, with more laterally positioned tumors in the PPF or infratem- resultant chronic sinusitis and the possibility of an oro- poral fossa. The approach used for the PPF biopsy in 2 pa- antral fistula. tients in our series (cases 2 and 3) first identifies the sphe- Endoscopic procedures have the advantage of elimi- nopalatine foramen medially, similar to the approach used nating external and oral incisions, thereby reducing in- for sphenopalatine artery ligation for epistaxis.12 This al- jury to the sinuses and parasinus structures. Endo- lows for identification and preservation of the spheno- scopes improve visualization of difficult-to-reach areas palatine vessels and removes the posterior wall of the max- such as the PPF compared with conventional open ap- illary sinus from medial to lateral superior to the vessels. proaches, thereby reducing the risk of neurovascular in- This reduces the likelihood of vascular injury to the sphe- jury. nopalatine vessels, which is one of the main risks of any This article reports on the endoscopic approach to approach to the PPF. Also, dissection and biopsy in the the PPF in 3 patients. The first patient had a complete superior portion of the PPF further reduces the risk to the resection of a schwannoma. This is only the third re- IMA, since this vessel resides more inferiorly in the PPF. ported case of an endoscopic resection of a PPF tumor, The mucosa of the posterior maxillary sinus is redraped to our knowledge, all of which were schwannomas. over exposed bone of the PPF at the end of the proce- Klossek et al14 also described a complete endoscopic re- dure, allowing for better healing and less crusting of ex- moval of a PPF schwannoma through a transnasal ap- posed bone. proach. Pasquini et al15 reported on a case of a partial trans- All patients in this series did have postoperative sen- nasal endoscopic removal of the PPF portion of a sory deficits in portions of the distribution of the max- schwannoma that extended into the cavernous sinus. In illary distribution of V2: the first patient as a result of the none of these 3 reported cases was there any vascular com- schwannoma involving the maxillary division of V2, the plication. second as a result of an intentional biopsy of a small branch The other 2 patients had endoscopic transnasal trans- of V2, and the third patient as a result of tumor involve- maxillary biopsies of the PPF as part of a workup for sus- ment of V2. The neural structures in the PPF were iden- pected tumor in the PPF. One patient also had a revision tified endoscopically, and this helped to avoid further un- procedure done endoscopically through the initial surgi- necessary injury.

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©2003 American Medical Association. All rights reserved. Downloaded From: https://jamanetwork.com/ on 09/30/2021 management of sinonasal inverted papilloma. Am J Rhinol. 1999;13: CONCLUSIONS 423-426. 3. Schlosser RJ, Mason JC, Gross CW. Aggressive endoscopic resection of in- The endoscopic approach to the PPF is a safe and effec- verted papilloma: an update. Otolaryngol Head Neck Surg. 2001;125:49-53. tive surgical procedure. This approach can be used for 4. Mattox DE, Kennedy DW. Endoscopic management of cerebrospinal fluid leaks both diagnostic biopsy and definitive tumor removal and cephaloceles. Laryngoscope. 1990;100:857-862. where appropriate. The approach described herein pro- 5. Lanza DC, O’Brien DA, Kennedy DW. Endoscopic repair of cerebrospinal fluid fistulae and encephaloceles. Laryngoscope. 1996;106:1119-1125. ceeds from medial to lateral, allowing for identification 6. Kennedy DW, Goodstein ML, Miller NR, Zinreich SJ. Endoscopic transnasal or- of the sphenopalatine vasculature early in the proce- bital decompression. Arch Otolaryngol Head Neck Surg. 1990;116:275-282. dure to reduce the risk of vascular injury, which could 7. Metson R, Dallow RL, Shore JW. Endoscopic orbital decompression. Laryngo- obscure the endoscopic view. Lateral extension can pro- scope. 1994;104(8, pt 1):950-957. 8. Kelley TF, Stankiewicz JA, Chow JM, Origitano TC. Endoscopic transsphenoidal vide access to the inferior orbital fissure. The use of an biopsy of the sphenoid and clival mass. Am J Rhinol. 1999;13:17-21. image-guided system is a useful adjunct to this surgical 9. Kingdom TK, DelGaudio JM. Endoscopic management of lesions of the sphe- approach. noid sinus, orbital apex, and clivus. Paper presented at: American Rhinologic Society Meeting; September 8, 2001; Denver, Colo. Accepted for publication September 5, 2002. 10. Sethi DS, Pillay PK. Endoscopic management of lesions of the sella turcica. J Laryngol Otol. 1995;109:956-962. Corresponding author: John M. DelGaudio, MD, De- 11. Snyderman CH, Goldman SA, Carrau RL, Ferguson BJ, Grandis JR. Endoscopic partment of Otolaryngology–Head and Neck Surgery, Emory sphenopalatine artery ligation is an effective method of treatment for posterior University School of Medicine, 1365 Clifton Rd NE, At- epistaxis. Am J Rhinol. 1999;13:137-140. lanta, GA 30322 (e-mail: john_delgaudio@emoryhealthcare 12. Bolger WE, Borgie RC, Melder P. The role of the crista ethmoidalis in endoscopic sphenopalatine artery ligation. Am J Rhinol. 1999;13:81-86. .org). 13. Chandler JR, Serrins AJ. Transantral ligation of the internal maxillary artery for epistaxis. Laryngoscope. 1965;75:1151-1159. REFERENCES 14. Klossek JM, Ferrie JC, Goujon JM, Fontanel JP. Endoscopic approach of the pterygopalatine fossa: report of one case. Rhinology. 1994;32:208-210. 15. Pasquini E, Sciarretta V, Farneti G, Ippolito A, Mazzatenta D, Frank G. Endo- 1. Thaler ER, Kotapka M, Lanza DC, Kennedy DW. Endoscopically assisted anterior scopic endonasal approach for the treatment of benign schwannoma of the si- cranial skull base resection of sinonasal tumors. Am J Rhinol. 1999;13:303- nonasal tract and pterygopalatine fossa. Am J Rhinol. 2002;16:113-118. 310. 16. Lane AP, Bolger WE. Endoscopic transmaxillary biopsy of pterygopalatine space 2. Tufano RP, Thaler ER, Lanza DC, Goldberg AN, Kennedy DW. Endoscopic masses: a preliminary report. Am J Rhinol. 2002;16:109-112.

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