Anatomic variations of sphenopalatine artery and minimally invasive surgical cauterization procedure Rasit Midilli, M.D.,1 Mustafa Orhan, M.D.,2 Canan Y. Saylam, M.D.,2 Serdar Akyildiz, M.D.,1 Sercan Gode, M.D.,1 and Bulent Karci, M.D.1 ABSTRACT Background: Sphenopalatine artery (SPA) ligation or cauterization stands to be one of the most common management options of refractory epistaxis. Ramification pattern of SPA as it passes through sphenopalatine foramen (SPF) has not been clearly established. The aim of this study is to investigate situations in which middle meatal approach may fail due to anatomic variations of SPA and to define a minimally invasive surgical cauterization procedure. Anatomic variations of SPA were determined by microdissection of 20 adult sagittally cross-sectioned head specimens. Methods: Branching characteristics of SPA and its anatomic relations were evaluated and anatomic variations were noted. Results: SPA was generally (80%) forming branches within SPF before entering into the nasal cavity. In 20% of the specimens, SPF was located superior to the horizontal lamella of the middle turbinate, and accessory foramen was present in 10%. In 10% of the cases, the posterior lateral nasal branch was situated as two branches in a deep sulcus in the middle meatus. Conclusion: The ramification pattern of SPA can not be fully exposed without resection of the posterior part of the middle turbinate via the middle meatal approach. Two-step procedures are advocated in reducing failure rates. Previously defined two-step procedures are relatively invasive. A less invasive procedure is defined based on the variations of SPA and SPF. (Am J Rhinol Allergy 23, e38 –e41, 2009; doi: 10.2500/ajra.2009.23.3403) Key words: Anatomic variations, anatomy, cauterization, epistaxis, posterior nasal bleeding, sphenopalatine artery, sphenopalatine foramen, variations
T
he sphenopalatine artery (SPA) enters into the nasal cavity through the sphenopalatine foramen (SPF), which is generally located inferior to the sphenoethmoidal recess.1,2 Ramification pattern of the SPA as it passes through the SPF has not been clearly established. It passes through the foramen as a single stem artery or more frequently leaves the foramen as two or more branches.3–6 Although the posterior septal artery (PSA), derived from the SPA, supplies blood to the septum; the posterior lateral nasal artery (PLNA) branches off to supply the middle turbinate, the inferior turbinate, and the fontanelle.3,4 Cauterization or ligation of the SPA is an alternative method, especially if nasal packing fails to stop bleeding or in recurrent epistaxis cases. Recently, SPA cauterization and ligation have become preferred methods, because more proximal approaches such as transantral approach are more invasive and have a lower success rate because of the anastomoses. Different failure rates regarding middle meatal approach were reported to be ⬃5–10%.5–8 Prolonged epistaxis in some cases after SPA cauterization or ligation suggests that there may be some missing points in surgical technique, which basically depends on regional anatomy of the patient. The aim of this study is to investigate the situations in which the middle meatal approach may fail due to anatomic variations of the SPA and its branches in cadaver dissections. Furthermore, the secondary goal is to define a less invasive surgical procedure for the cauterization of the SPA.
MATERIALS AND METHODS Twenty sagittally cross-sectioned adult head specimens of 20 cadavers (9 from left the side and 11 form the right side), were examined. Dissection was performed by using a surgical microscope. An electronic digital caliper was used for the measurements and a 1-mm spaced ruler was used for the pictures. From the Departments of 1Otorhinolaryngology and 2Anatomy, Ege University Faculty of Medicine, Bornova, I˙zmir, Turkey Address correspondence and reprint requests to Sercan Gode, M.D., Ege Universitesi Hastanesi Kulak Burun Bogaz Bolumu, 35040, Bornova Izmir, Turkey E-mail address:
[email protected] Copyright © 2009, OceanSide Publications, Inc., U.S.A.
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Dissection was initiated by elevation of the middle meatal mucosa up to the anterior wall of the sphenoid sinus until the SPF was totally revealed. Branching characteristic of the SPA and their relation with important anatomic landmarks were evaluated. These anatomic landmarks are listed in Table 1. Pitfalls in elevation of the mucosa through the foramen on the lateral nasal wall and anatomic variations that may interfere with cauterization of the SPA via endoscopic middle meatal approach were all assessed.
RESULTS Location of SPF In 90% (n ⫽ 18) of the specimens, the SPF appeared as a single foramen, whereas in 10% (n ⫽ 2) there was more than one foramen because of bony bridges (Fig. 1). The SPF was located superior to the horizontal lamina of the middle turbinate in 20% (n ⫽ 4) of the cadavers, whereas it was located at the transition of the middle and superior meatus in 80% (n ⫽ 16) of the cadavers. The vertical distance between the inferior tip of the SPF and the base of the nose was 22.1 ⫾ 3.0 mm (16.6–29.6 mm).
Ramification Characteristics of the SPA on the Lateral Nasal Wall The SPA was branching off within the foramen in 80% (n ⫽ 16) of the cases and just after entering the nasal cavity in 20% (n ⫽ 4) of cases. There were two main branches in 80% (n ⫽ 16), three in 15% (n ⫽ 3), and four in 5% (n ⫽ 1) of cadavers. The two branches in 16 sections were the PSA and PLNA. In specimens with more than two branches, two had an additional posterior septal branch; one had an additional branch to the superior turbinate; and one had separate branches for superior, middle, and inferior turbinates in addition to the PSA. In cases with more than one SPF, main branches of the SPA coursed within different foramens. The PLNA was branching off in various numbers to the middle and the inferior turbinates. In 10% (n ⫽ 2) of the cases, PLNA was running as two branches in a deep sulcus in the middle meatus. Ramification level and patterns of PLNA varied among specimens (Fig. 2). After removal of the middle turbinate, the arteries coursing on the lateral nasal wall were exposed.
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Table 1 Important anatomical landmarks used in the study Posterior Tip of Middle Turbinate Choanae Horizontal lamella and posterior insertion of middle turbinate Inferior turbinate
Maxillary Sinus Ostium Base of the nose Sphenoid sinus ostium Posterior insertion of superior turbinate
There were two arteries in 85% (n ⫽ 17) and three in 15% (n ⫽ 3). The ramification was at the middle meatus level in 88% (n ⫽ 15), whereas ramification was superior to the middle meatus in 12% (n ⫽ 2).
Course of PSA The PSA crossed the lower portion of the anterior wall of the sphenoid sinus and ran toward the septum. In 11 specimens (55%), the PSA was located at the posterior insertion of the superior turbinate, and it ran toward the anterior wall of the sphenoid sinus. On the other hand, in 45% of cadavers the PSA was located either posterior to insertion of the superior turbinate or anterior to it (see Fig. 4). The supreme turbinate was present in four cases (20%). The PSA was located anterior to the insertion point of the superior turbinate in all four cases in which the supreme turbinate was present. Relations of main SPA branches and some important anatomic landmarks are shown in Table 2 and Fig. 3. As seen in Table 2, none of the anatomic landmarks was constant or predictive for the localization of SPF. The most conspicuous data in this study were that the PSA localized almost always on the posterosuperior border of the middle turbinate. Relatively, the most constant landmark for the PLNA was the posterior tip of the middle turbinate (Fig. 3).
DISCUSSION In massive or recurrent posterior epistaxis cases, the endoscopic approach to cauterize or ligate the SPA is an effective and popular method. However, anatomic variations of the SPF and the SPA may cause surgical failure in a particular population. Therefore, it is important to understand the pattern and the course of the major branches of the SPA to define the major pitfalls of cauterization or ligation. The SPF is localized between the posterior end of the horizontal lamella of the middle turbinate and the horizontal lamella of the superior turbinate.4 Padua and Voegels reported the SPF to be most frequently at the transitional region of middle and superior meatus (86.9%) and less frequently at the superior meatus (13.1%).5 In our study the SPF was located at the superior meatus in 20%. Generally,
Figure 1. The bony bridge in the SPF and the SPA branching off before the foramen. (a) The bony bridge alone (arrow), (b and c) (the same sample) double-bridge (white arrows), (c) Two bony bridges have formed three foramens; the posterior septal artery (PSA) (*) passes through the upper foramen, and the posterior lateral nasal artery (PLNA) (⫹) passes through the lower foramen (posterior tip of the mt is removed). SPA ⫽ sphenopalatine artery; ss ⫽ sphenoid sinus; SPF ⫽ sphenopalatine foramen; mt ⫽ middle turbinate; it ⫽ inferior turbinate
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Figure 2. Ramification of PLNA (⫹) in the middle meatus (a) at superior part of the middle meatus and (b) at the inferior part of the middle meatus middle turbinate branch (white arrow) and inferior turbinate branch (black arrow). PLNA ⫽ posterior lateral nasal artery.
the SPF was found to be solitary in anatomic studies. However, in some studies there were more than one SPF because of bony bridges at the ethmoidal crest with different reported frequencies approximately around 10%.3,5,6 Our study correlated with the results mentioned previously by identifying more than one SPF in 10% of cadavers. One additional finding in our study is that there may be more than one bony bridge at the SPF, thus, more than two foramens (Fig. 1). Most surgical methods described before were similar and the middle meatal approach was the primary procedure. Although some authors preferred to perform uncinectomy and antrostomy, others have claimed that there is no need for it.7–9 After the incision was performed at the posteroinferior border of the bulla ethmoidalis, the mucoperiosteal flap is elevated posterosuperiorly through the posterior fontanelle until the SPF is visualized.7–12 Some authors proposed a two-step approach, middle meatal approach with sphenoidotomy, to overcome failures.8,11 Combining an extensive middle meatal approach with sphenoidotomy is a relatively hard and invasive procedure to perform in a person without a sinus pathology. There are two major problems with these aforementioned surgical procedures. The first one is incomplete visualization of the SPF, as is observed in some of our cadaver specimens, which may be located more posterior and superior to the end point of the horizontal lamella of the middle turbinate.5,8 It is recommended in the literature that posterosuperior elevation should be performed as much as possible to deal with this problem. However, the SPF may be localized so high that it can not be visualized without resecting the posterior part of the middle turbinate. Some authors recommend resection of the posterior portion of the middle turbinate.11 In an epistaxis case, an injury to an important landmark, such as the middle turbinate, is controversial and should also be discussed. It is not always possible to reach the SPF via the middle meatal approach (see Fig. 5), where it is far more hard to expose the PSA. The point where the PSA leaves the SPF is generally a superior location for the middle meatal approach (Fig. 4). The second pitfall of the middle meatal approach is relatively frequently encountered variations of the SPA and bony lateral nasal wall. Deep grooves that emerge from the SPF were formerly reported in other studies but these were used to define variability of bony elements in the lateral nasal wall.6 In our study, 10% of specimens has had PLNA as two separate branches in a deep sulcus in the middle meatus, which, in fact, may resemble SPF in endoscopic surgery (Fig. 5). With the middle meatal approach, generally, the first encountered artery is PLNA, which might be running as two arteries and ramify at various levels (Fig. 2). Because of the reasons mentioned previously, the surgeon may think that he had ligated the SPA at the SPF, which he actually might have ligated a branch of PLNA. Some authors also recommend a dissection from the posterior wall of the maxillary sinus
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Table 2 Relation of the sphenopalatine foramen and sphenopalatine artery with particular anatomical landmarks that are shown in Fig. 4 Distances (mm)
a
b
c
d
e
f
g
Mean distance Maximum/minimum distance
21.7 ⫾ 3.03 16.5/26
9.4 ⫾ 2.04 6/12.7
8.3 ⫾ 1.7 5/11.7
7.7 ⫾ 2.04 3.3/10.09
8.1 ⫾ 2.46 3.8/11.6
4.3 ⫾ 1.69 1/7.4
22.1 ⫾ 3.0 16.6/29.6
Figure 4. The relationship between the exit point of the PSA (*) at the SPF and posterior tip (arrow) of the st. (a) at posterior, (b) at superior, *c) at posterosuperior, (d) at anterosuperior, and (e) at anteroinferior. ss ⫽ sphenoid sinus; spt ⫽ supreme turbinate; SPF ⫽ sphenopalatine foramen; PSA ⫽ posterior septal artery; mt ⫽ middle turbinate; st ⫽ superior turbinate; SPF ⫽ sphenopalatine foramen; PSA ⫽ posterior septal artery.
Figure 3. Relations between the main SPA branches and particular anatomic landmarks. (a) *, PSA; ⫹, PLNA; (b) straight and dotted lines indicate the following relations: a, separation of PLNA at SPF—maxillary sinus ostium; b, separation of PLNA at SPF—choanae; c, separation of PLNA at SPF—posterior adhesion site of the middle turbinate; d, separation of PSA at SPF—posterior tip of the middle turbinate (transverse); e, separation of PSA at SPF—posterior tip of the middle turbinate (vertical); f, separation of SPA at SPF—upper end point of horizontal lamella of the middle turbinate; the inferior tip of SPF—base of the nose. SPA ⫽ sphenopalatine artery; SPF ⫽ sphenopalatine foramen; PSA ⫽ posterior septal artery; PLNA ⫽ posterior lateral nasal artery.
to the anterior wall of the sphenoid sinus.7 However, with this approach, it is impossible to perform such a dissection without an injury to the middle meatus. Furthermore, the more invasive the procedure is, the more postoperative complications such as crusting, synechia, and sinusitis will be encountered.
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The two major problems related to the middle meatal approach are incomplete visualization of the SPF and partial cauterization of the SPA. In this study, one of the most constant anatomic data was the localization of the PSA at the posterosuperior border of the middle turbinate. A highly variable anatomy of the SPF and relatively constant course of PSA directed us to an alternative surgical approach: two-step cauterization rather than the sole middle meatal approach. In the first step, the PLNA can be easily ligated at the region close to the posterior tip of the middle turbinate with limited mucosal injury and bleeding. In the next step, rather than an extended dissection from the middle meatus to expose the SPF totally, the middle turbinate is lateralized and an incision 2–3 mm posterior to the posterior border of the middle turbinate is performed. PSA can be visualized by elevating the mucosa on the anterior wall of the sphenoid. It is of vital importance to mention here that if the supreme nasal turbinate is present, the PSA lies almost always anteriorly to the posterior insertion of superior turbinate. Thus, the supreme turbinate is a relatively common variation (20%); it is advocated to check the presence of it before cauterization of PSA (Fig. 4). The PSA is a relatively thin artery and exposure for ligation is sometimes impossible. Although PSA is not visualized, cauterization of the region where bleeding has started will be sufficient. Cauterization of these two branches separately with this approach not only eliminates the requirement for the SPF dissection and sphenoidotomy, but also provides a successful cauterization in cases of accessory SPF. Isaacs and Goyal described the neural structures in pterygopalatine fossa to be placed superior to the SPF.13 Possible injuries to the vidian and maxillary nerves and sphenopalatine ganglion encountered during SPF dissection may be reduced by this meticulous approach. Because there is no need for an elevation up to the superior border of the SPF, a relatively less invasive proce-
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in three refractory epistaxis cases. Although we have a limited number of patients and short follow-up time, postoperative results are promising.
CONCLUSION The SPA ligation or cauterization, performed only by using the middle meatal approach, may not be successful because of the anatomic variations of the SPF and the SPA. To prevent this, the most feasible procedure is the cauterization by a two-step approach. Based on the anatomic data, the two-step procedure advocated here is a relatively less invasive method in cauterization of the SPA. Because the extent of the mucosal elevation is limited, the injuries to the nerves around the SPF and middle turbinate will be minimized.
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Figure 5. Bleeding can not be controlled by only the middle meatal approach. (a and b) Exit of PSA (*) from SPF is seen when the posterior tip of the st is elevated. (c) The exit of PSA (*) and PLNA (⫹) from the SPF is seen when the posterior tip of the middle turbinate (mt) is elevated. (d) The endoscopic appearance of the branches of PLNA at posterior tip of middle turbinate. Ligation of only these branches at the middle meatus may cause failure of the surgical procedure. Ss ⫽ sphenoid sinus; spt ⫽ supreme turbinate; it ⫽ inferior turbinate; eb ⫽ ethmoidal bulla, middle turbinate branch (white arrow), inferior turbinate branch (black arrow); st ⫽ superior turbinate; SPF ⫽ sphenopalatine foramen; PSA ⫽ posterior septal artery; PLNA ⫽ poeterior lateral nasal artery.
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dure is applied to the middle turbinate, nasal mucosa, and pterygopalatine fossa. Rarely, multiple branching of the SPA may be encountered in the SPF. To overcome this variation, the cauterization or ligation should be performed at the possible closest area to SPF. Because these branches run quite close to each other, the presence of a second branch should always be checked by a 4- to 5-mm dissection after the artery is visualized. The two-step approach advocated here was based on sole anatomic data; thus, additional clinical trials are required to confirm whether this method is more effective and less invasive or not. In our department we successfully tried this approach
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