The Sewall-Boyden technique of reconstructing the frontonasal tract

The Sewall-Boyden technique of reconstructing the frontonasal tract

Operative Techniques in Otolaryngology (2010) 21, 122-129 The Sewall-Boyden technique of reconstructing the frontonasal tract Andrew H. Murr, MD, FAC...

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Operative Techniques in Otolaryngology (2010) 21, 122-129

The Sewall-Boyden technique of reconstructing the frontonasal tract Andrew H. Murr, MD, FACS From the Department of Otolaryngology-Head and Neck Surgery, University of California, San Francisco, California. KEYWORDS Sewall-Boyden flap; Frontonasal tract; Reconstruction; Frontoethmoidectomy

The Sewall-Boyden flap reconstruction of the surgically created frontonasal tract created during a classic Lynch frontoethmoidectomy is a procedure that philosophically is in keeping with modern concepts of sinus and mucosa preservation that are the hallmarks of successful modern endoscopic sinus surgery. Although the procedure is now mostly of historical interest, the basis of the “frontal sinus rescue” operation and basic tenets of frontal sinus surgery owe some of their intellectual development to this mucosal flap– based tract reconstruction technique. This article provides a step by step description with detailed drawings of the technique to provide a basis for study of the procedure. Although occasionally used adjunctively today for narrow indications, the Sewall-Boyden technique has been largely replaced by endoscopic transnasal surgery procedures such as the Endoscopic Lothrop and the Draf 3. © 2010 Elsevier Inc. All rights reserved.

Over the last century, much thought, effort, print, and paper have been devoted to the treatment of frontal sinus disease.1,2 The effort to solve the puzzle of surgery on the frontal sinus is definitely out of proportion to the incidence of surgical frontal sinus disease in the population. The reason for this misappropriation of attention is due to the intricacy of the surgical anatomy of the ethmoid labyrinth, the severity of complications that can result from untreated frontal sinus disease, the tenacity of the disease, the longevity of the problem, and the difficulty of the surgery. Historically, the problem was compounded by the difficulty produced by the inaccessibility of the sinuses in general to common physical examination skills. Today, we have fiberoptic endoscopes and computerized imaging in three planes, which allow specialist physicians to make a quick diagnosis in a facile manner. Yet, endoscopes were not commonly available for nasal examination in the United States prior to the mid-1980s, and computerized imaging was not commonly available in three planes until just sevAddress reprint requests and correspondence: Andrew H. Murr, MD, FACS, Department of Otolaryngology-Head and Neck Surgery, University of California, San Francisco 2233 Post Street, 3rd Floor, San Francisco, CA 94115. E-mail address: [email protected] 1043-1810/$ -see front matter © 2010 Elsevier Inc. All rights reserved. doi:10.1016/j.otot.2010.03.006

eral years ago. Most primary care physicians do not have the desire to learn endoscopic examination skills or have the will to increase their ability to interpret multiplanar sinus computed tomography (CT) imaging. The responsibility for the clinical evaluation of frontal sinus problems rests firmly in the purview of several groups of specialty physicians. Although endoscopic surgical techniques dominate the common practice of Otolaryngology today, just 20 years ago, the best technique for approaching frontal sinus disease was still hotly debated. A major textbook published in 1993 mentioned endoscopic approaches to the frontal sinus only in the process of condemning the procedure as dangerous.3 This was prior to the dissemination of image-guidance surgery, properly sized through cutting frontal sinus instrumentation, and a full understanding of the anatomic development of the anterior ethmoid complex. The “gold standard” for frontal sinus surgery was an obliteration technique popularized by Bergara and then William Montgomery. The goal of this technique was to open the frontal sinus through a bicoronal forehead flap, drill out the mucosa of the sinus completely, and then fill the sinus with a substance that would isolate the sinus from the nose and prevent mucosa regrowth and mucocele formation.4 In Otolaryngology-Head and Neck Surgery, abdominal wall fat was the obliteration


Sewall-Boyden Technique

substance of choice, but bone, gelfoam, muscle, pericranium, and other substances, including alloplastic materials, were also used. This surgery was designed to eliminate the connection of the sinus to the nose and to prevent the frontal sinus from being an air-containing space. This surgery had a fairly dependable track record and is still used today. The competing surgery to the frontal sinus osteoplastic flap obliteration procedure was related to the sophisticated and technically demanding endoscopic procedures performed today. The procedure was a Lynch external frontoethmoidectomy procedure.5 This procedure was designed to preserve the frontal sinus as an air-containing space connected to the nose. An external ethmoidectomy was performed through a skin incision in the medial orbit, and the ethmoid cells were exenterated under direct visualization. The key goal of the surgery was to use a stent to try to prevent the surgical opening between the nose and the frontal sinus from stenosing. Several authors spent much effort studying stenting material in both human and animal models.6 The main reason for the interest in finding a suitable stent material was because this surgical opening seemed to close off over time in about 33% of cases, which placed the patient at risk for mucocele formation, central nervous system complications, or return of symptoms. Papers were disseminated on the use of red rubber catheters, silicone sheeting, and metals in various shapes and configurations and for various times to try to solve the stenosis problem. In the end, the surgical trauma of removing anterior ethmoid cells and drilling openings into the frontal sinus seemed to create a circumferential tract that naturally tended to create a fibrotic cicatrical reaction that limited the success of this procedure. Although several centers preferred and taught this procedure, its use never really became completely disseminated or universally accepted. Yet, the overall philosophy of this surgical concept was to preserve the sinus as an aerated space, which is in keeping with modern concepts of surgical goals in sinus surgery. One variant of the Lynch frontoethmoidectomy was a procedure that is called a frontoethmoidectomy with SewallBoyden reconstruction. This procedure was described by a number of physicians over the years, including Sewall, Boyden, McNaught, Ogura, Baron, Henry, and Dedo.7-14 The idea of this procedure was to not rely on a stent for remucosalization of the surgically created opening between the nose and the frontal sinus. Instead, this procedure depended on a septal mucosal flap to reline the surgically created tract, recognizing the tendency of the surgically traumatized drainage channel to regularly stenose. The key elements of this procedure were atraumatic surgical technique to prevent stenosis, wide visualization of the anatomy, minimal incisions, respect for minimizing mucosal resection, and preservation of the sinus as an aerated space. In fact, these concepts are fairly well accepted today as basic tenets of successful endoscopic surgery. Many authors of modern endoscopic surgical techniques have used the Sewall-Boyden concept as a basis for refining endoscopic frontal sinus surgery techniques because the procedure was dedicated to the preservation of an aerated and functioning frontal si-

123 nus.15-17 Nevertheless, the Sewall-Boyden modification was never widely dissemintated despite its high published success rate. Mainly, the reason probably lies in the difficulty in communicating the steps of creating the septal mucosal flap combined with the difficulty in teaching the technique without the visualization afforded by endoscopes.

Indications There are few modern indications for a frontoethmoidectomy with Sewall-Boyden flap reconstruction in today’s surgical armamentarium. Certainly, there are no absolute indications for the procedure. However, by studying this technique, problems with frontal tract stenosis can be reviewed and perhaps the concept of, or aspects of, the technique can be incorporated into current endoscopic surgical practice. In essence, this technique is a central study of using mucosal flaps to reconstruct a frontonasal opening that is lined by minimally traumatized mucosa to preserve the function and aeration of the frontal sinus. The limiting factor in transnasal endoscopic procedures that address the frontal sinus remains the issue of stenosis. Modern surgical case series have stenosis as a major complication or limitation of the surgery and scarring of the frontonasal surgically created opening can approach 30% or more, even in modern series. Especially techniques that rely on drilling can be prone to postoperative hyperostosis and subsequent cicatrix formation resulting in a need for surgical revision. The “frontal sinus rescue procedure” is actually a Sewall-Boyden mucosal flap accomplished endoscopically, whose purpose is to recreate an aerated frontal sinus after a failed or poorly functioning obliteration procedure.18 Keeping this in mind, the indications for an endoscopic Sewall-Boyden mucosal reconstruction technique are cases where extensive surgery or drilling is done and there is concern about eventual stenosis formation or when a frontal sinus rescue procedure is accomplished to reverse an osteoplastic obliteration procedure. An external frontoethmoidectomy with Sewall-Boyden flap reconstruction may still be an adjunct to skull base procedures where a mucosal flap is desirable for CSF leak closure or for dural coverage, or if sophisticated instrumentation is unavailable for a frontal sinus surgical procedure that would otherwise be accomplished with a Draf 3 or endoscopic Lothrop technique.

Technique14 The procedure is performed under general anesthesia in an operating room setting. The patient is placed on an operating room table and rotated 180 degrees from the point of intubation to allow complete and unencumbered access to the head and face. A long anesthesia circuit is needed because the circuit will run down the length of the patient’s body. The table is put into a semisitting or beach chair position to minimize venous engorgement. The head is


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Figure 1 A frontoethmoidectomy incision is outlined, and a bone flap to remove portions of the frontal, maxillary, lacrimal, and nasal bone is designed. (Reproduced from Dedo et al,14 with permission from OceanSide Publications, Inc.) (Color version of figure is available online.)

padded with a gel doughnut or foam ring pillow. Four percent cocaine is soaked onto 0.5- by 3-inch-long cottonoids with sutures attached and packed into both sides of the nose after the application of oxymetazoline spray. The incision is marked out on the side of the intended surgery. The incision is a curvilinear incision midway between the medial canthal tendon and the glabella at the medial side of the orbit (Figure 1). A running W-plasty can be incorporated into the incision to help prevent webbing and to camouflage the incision. If a W-plasty is not used, methylene blue can be used to mark the incision to allow precise closure. The incision is injected with lidocaine 1% with epinephrine 1:100,000 using a 27-gauge, 1.5-inch needle and control syringe to provide hemostatsis. A corneal shield may be placed or a tarsorraphy stitch used. At this point, the surgical team can scrub and the circulating nurse can accomplish skin preparation while the topical and injectable hemostatic agents begin their effect. A head drape is typically used, and a split sheet is used to cover the patient’s chest. The surgical team uses fiberoptic headlights to allow for maximal visualization. A #15 style blade is used to complete the skin incision while fine, two-pronged skin hooks are deployed to allow access to the subcutaneous tissue. The incision is opened in layers being mindful that branches of the angular artery, which is a facial artery branch, are just below the skin at this location. Bipolar cautery is used prior to incision of the angular branches to prevent troublesome and time-consuming bleeding. Alternatively, the angular vessels can be individually ligated with 4-0 silk sutures. The incision is brought down to the periostium of the medial orbit. At this point, the operating surgeon uses a Cottle elevator and a #7 Frazier suction to raise the orbital

contents from a medial to lateral direction along a broad plane. The frontoethmoid suture line is identified as well as the lacrimal sac. The lacrimal sac is elevated from the orbit

Figure 2 An otologic drill is a tool suitable for turning the bone flap while preserving the underlying mucosa. A surgical clip is placed on the anterior ethmoid artery seen at the frontoethmoid suture line. (Reproduced from Dedo et al,14 with permission from OceanSide Publications, Inc.) (Color version of figure is available online.)


Sewall-Boyden Technique

Figure 3 The frontal beak can be drilled under direct visualization after the bone flap is lifted and removed. (Reproduced from Dedo et al,14 with permission from OceanSide Publications, Inc.) (Color version of figure is available online.)

but is not transected inferiorly. The frontoethmoid suture line is used to guide the deeper dissection and marks the level of the skull base, in general. Sewall retractors are used to retract the orbital contents and to provide deep exposure into the narrow surgical field. The anterior ethmoid artery is usually just below the level of the frontoethmoid suture line and is approximately 21 mm from the posterior lacrimal crest. The anterior ethmoid artery is identified and isolated, and a surgical clip is placed on the vessel. Typically a small

Figure 4 CT scan showing the bone flap removed to create the septal mucosal flap.


Figure 5 The septal mucosa flap is elevated with a freer after the exenteration of the ethmoid cells and partial removal of the frontal sinus floor. (Reproduced from Dedo et al,14 with permission from OceanSide Publications, Inc.) (Color version of figure is available online.)

straight clip applier is required because a curved clip applier can sometimes be too curved to allow easy placement into the narrow dissection field. With the anterior ethmoid artery clipped, it can be divided if this is necessary for exposure. An otologic drill is then used to remove a bone flap from the area of the lacrimal bone, frontal bone, maxillary bone, and just on to the nasal bone (Figure 2). The area of this bone flap anteriorly is on the lateral nasal wall near the region where a lateral osteotomy is created during rhinoplasty. The bone flap is elevated and separated from the underlying mucosa in a manner similar to the way a dural bone flap is removed with an otologic drill. At this point, the external ethmoidectomy can begin. The lacrimal fossa is the safest place to begin the ethmoidectomy because it is always on the nasal side and not the cranial cavity side of the dissection. A Blakesly forceps can be used to punch through the fossa and ethmoid cells can then be exenterated with either through cutting or grasping instruments. The surgeon uses the dissection instrument in one hand and a Frazier suction in the other. The surgeon is constantly aware that the frontoethmoid suture line is a landmark that approximates the position of the skull base but that the skull base may in fact be above or below this suture line. Ethmoid cells are exenterated from anterior to posterior with identification of the middle turbinate, grand lamella, and the sphenoid face. A middle meatus antrostomy can be accomplished. The ethmoidectomy can be tailored to the disease as in any type of sinus surgery. At this point, dissection of the anterior ethmoid tract and the frontal opening can be pursued. It is important to realize that the


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Figure 6 The superior mucosal cut is made to develop the flap after elevation. (Reproduced from Dedo et al,14 with permission from OceanSide Publications, Inc.) (Color version of figure is available online.)

anterior ethmoid artery generally marks the transition of the skull base from the fovea ethmoidalis to the posterior wall of the frontal sinus. With this in mind, dissection anterior to the anterior ethmoid artery can be accomplished with a high degree of safety and confidence. A

Figure 8 A laterally based flap has been designed to line the orbital periostium and reaches up into the frontal sinus. (Reproduced from Dedo et al,14 with permission from OceanSide Publications, Inc.) (Color version of figure is available online.)

Kerrison rongeur is an excellent tool for taking down the medial orbital wall comprised of the ethmoid bone, lacrimal bone, and frontal bone to allow entrance through

Figure 7 The inferior incision is made in the septal mucosal flap. The flap can still be medially or laterally based if desired. A dotted line marks the incision to create a laterally based septal mucosal flap. (Reproduced from Dedo et al,14 with permission from OceanSide Publications, Inc.) (Color version of figure is available online.)

Figure 9 This diagram shows the length of a laterally based septal mucosa flap in its raised position. (Reproduced from Dedo et al,14 with permission from OceanSide Publications, Inc.) (Color version of figure is available online.)


Sewall-Boyden Technique


Figure 10 The diagram on the left depicts a medially based flap. The diagram on the right shows two laterally based flaps created by removing the superior nasal septum while preserving the septal mucosa. This procedure is quite similar to the Draf 3 operation. (Reproduced from Dedo et al,14 with permission from OceanSide Publications, Inc.) (Color version of figure is available online.)

the floor of the frontal sinus. Surprisingly wide exposure of the frontal sinus from the inferior aspect under direct visualization results. The primary task of the surgery can then be accomplished. This may include tumor extirpation, removal of infected or inflamed tissue, closure of a cerebralspinal fluid leak, or whatever the original purpose of the designed surgical procedure. The frontal sinus septum can be drilled under direct visualization to accomplish bilateral surgery if necessary. If the superior nasal septum is drilled away, the procedure is converted to one very similar to a Draf 3. Also, the frontal “beak” or “delta area” can be drilled under direct visualization if necessary or advantageous (Figure 3). The septal flap or Sewall-Boyden Flap is then elevated as part of the procedure to begin closure. At this point, the nasal–maxillary–frontal bone flap has been removed and the ethmoidectomy has been accomplished. However, the mucosa beneath the bone is in tact. This mucosa is the lining of the nasal bones and maxilla and the lining of the superior nasal septum adjacent to the nasal bones. The mucosa is just posterior to the area of the nasal valve and corresponds to the area of mucosa that is lifted with a Goldman elevator during a closed reduction of nasal fracture (Figure 4). This flap of mucosa can be lifted off the superior septum corresponding to the perpendicular plate of the ethmoid with a Cottle elevator (Figure 5). A caudal mucosal cut parallel to the edge of the caudal septum must then be made with a sharp scissor to release the flap inferiorly and this cut will determine the width of the septal flap (Figure 6). An inferior cut must then be made to determine the length of the flap. If the inferior cut is made medially, the flap will be based laterally (Figure 7). If the inferior cut is made laterally, then the flap will be based on a medial pedicle. Once this cut is made, the flap can then be rotated and unfurled into position to line the newly created surgical frontal tract. A laterally based flap has the added benefit of lining the orbital contents (Figure 8). The superior border of the flap can be sutured to the edge of the frontal mucosa. A mucosal-lined tract results, and a rolled silastic sheet can be placed in the new

tract and left in until the acute effects of surgery have moderated. Depending on the surgeon’s design, the SewallBoyden flap can be laterally based, medially based, or can be done in a bilateral laterally based fashion (Figures 9 and 10). Closure of the frontoethmoidectomy wound can then be accomplished in a layered fashion with deep chromic sutures, and fine nylon skin sutures. Alternatively, 6-0 fastabsorbing gut sutures can be used with good effect. Typically, medial canthal repositioning sutures are not required.

Complications Complications of the procedure include all the usual complications of ethmoidectomy, including brain injury,

Figure 11 The resultant facial scar from the procedure is well camouflaged.


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eye injury, bleeding, infection, and failure with the need for revision. It is possible to have diplopia after the procedure if the eye position is altered, although this is rare. Epiphora can occur if the lacrimal system is damaged. If the anterior ethmoid artery is avulsed or incompletely clipped, it can retract into the orbit and cause an orbital hematoma, which may be a vision-threatening emergency. Of course, there is a skin incision with the potential for scarring and prominence from an appearance standpoint, but this incision heals surprisingly well and imperceptibly in most cases, and few patients will notice or complain of the scar (Figure 11). The main complication of the surgery actually relates to the possibility of restenosis with attendant need for revision, which is the same problem facing all endoscopic techniques directed at entering the frontal sinus. The reported incidence in the literature of restenosis of a SewallBoyden flap is extremely low over the long term.

Discussion The Sewall-Boyden flap is an elegant operation and a well thought out solution to the problem of postoperative frontal tract stenosis that never caught on. The main reason for its lack of success is the difficulty in describing the operation in books and papers, the difficulty in drawing the operative steps to be published in atlases, and because it is difficult to obtain a good look at the steps of the surgery in the operating room setting. The Sewall-Boyden flap is really a “one-man” operation. The amazing thing about the technique is that the philosophy behind it was way ahead of its time. The procedure emphasized preservation of the frontal sinus as an aerated space and preservation of function. The operation emphasized the ability to assess patients in the office postsurgically without the need for imaging studies. The Sewall-Boyden flap technique emphasized mucosal preservation and the minimization of surgical trauma. It highlighted the need for astute anatomical knowledge. The technique minimized the postoperative stenosis that plagued the Lynch frontoethmoidectomy procedure and had a very high literature reported patency rate (Figure 12). If emulation is the highest form of flattery, then the Sewall-Boyden flap certainly has its share of fans. Philosophic elements of the the Draf 3 and the endoscopic Lothrop procedure are similar to the Sewall-Boyden.15-17 The use of flaps for CSF leak closure and the use of flaps to reverse obliteration procedures are more directly related to the Sewall-Boyden technique.18 In fact, the modern tenets of frontal sinus surgery emphasizing function, atraumatic technique, and mucosal preservation are all congruent with the principles of the Sewall-Boyden flap. Nevertheless, there are few reasons to contemplate this procedure today. With three-plane CT imaging, image guidance with active intraoperative imaging, and the development in instruments that has occurred in the last 10 years or so, most surgeons will be able to either prevent frontal sinus tract stenosis at

Figure 12 More than 10 years after surgery, the endoscopic examination is similar to what is seen after a Draf 3 procedure with removal of the intersinus septum and patent access to the frontal sinus.

the time of the original functional endoscopic sinus surgery (FESS) surgery or will be able to endoscopically widen the frontal outflow tract to prevent postoperative scarring.19,20 Yet, this flap technique may have some use when combined with endoscopic skull base surgery for reconstructive purposes after tumor or other extended surgery. Also, it is interesting to keep the technique fresh if ever one needs to operate without some of the sophisticated equipment that we have come to so heavily rely on today.

Acknowledgments I would like to acknowledge the assistance of Herbert H. Dedo, MD for teaching me the steps of the operation discussed in this manuscript, for providing patients from his practice for follow-up examination, and for providing collaboration and authorship on the key reference in the article.14

References 1. Jacobs JB: 100 Years of frontal sinus surgery. Laryngoscope 107:1-36, 1997 2. Close LG, Stewart MG: Looking around the corner: A review of the past 100 years of frontal sinusitis treatment. Laryngoscope 119:22932298, 2009 3. Montgomery WW: Controversies in surgery for chronic frontal sinusitis, in Bailey BJ (ed). Philadelphia, J B Lippincott, 1993, p 869 4. Hardy JM, Montgomery WW: Osteoplastic frontal sinusotomy: An analysis of 250 operations. Ann Otol Rhinol Laryngol 85:523-532, 1976 5. Neel HB III, McDonald TJ, Facer GW: Modified lynch procedure for chronic frontal sinus diseases: Rationale, technique, and long-term results. Laryngoscope 97:1274-1279, 1987


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6. Neel HB, Whicker JH, Lake CF: Thin rubber sheeting in frontal sinus surgery: Animal and clinical studies. Laryngoscope 86:524536, 1976 7. Baron SH, Dedo HH, Henry CR: The mucoperiosteal flap in frontal sinus surgery (The Sewall-Boyden-McNaught operation). Laryngoscope 83:1266-1280, 1973 8. Ogura JH, Watson RK, Jurema AA: Frontal sinus surgery. The use of muoperiosteal flap for reconstruction of a nasofrontal duct. Laryngoscope 70:1229-1243, 1960 9. Boyden GL: Surgical treatment of chronic frontal sinusitis. Ann Otol Rhinol Laryngol 61:558-566, 1952 10. Sewall EC: The operative treatment of nasal sinus disease. Ann Otol Rhinol Laryngol 44:307-316, 1935 11. McNaught RC: A refinement of the external frontoethmosphenoid operation. A new nasofrontal pedicle flap. Arch Otolaryngol 23:544549, 1936 12. Murr AH: Contemporary indications for external approaches to the paranasal sinuses. Otolaryngol Clin North Am 37:423-434, 2004 13. Murr AH, Dedo HH: Frontoethmoidectomy with Sewall-Boyden reconstruction: Indications, technique, and philosophy. Otolaryngol Clin North Am 34:153-165, 2001

129 14. Dedo HH, Broberg TG, Murr AH: Frontoethmoidectomy with SewallBoyden reconstruction: Alive and well, a 25-year experience. Am J Rhinol 12:191-198, 1998 15. Schlosser RJ, Zachmann G, Harrison S, et al: The endoscopic modified Lothrop: Long-term follow-up on 44 patients. Am J Rhinol 16:103108, 2002 16. Weber R, Draf W, Kratzsch B, et al: Modern concepts of frontal sinus surgery. Laryngoscope 111:137-146, 2001 17. McLaughlin RB, Hwang PH, Lanza DC: Endoscopic trans-septal frontal sinusotomy: The rationale and results of an alternative technique. Am J Rhinol 13:279-287, 1999 18. Citardi MJ, Javer AR, Kuhn FA: Revision endoscopic frontal sinusotomy with mucoperiosteal flap advancement: The frontal sinus rescue procedure. Otolaryngol Clin North Am 34:123-132, 2001 19. Chandra RK, Palmer JN, Tangsujarittham T, et al: Factors associated with failure of frontal sinusotomy in the early follow-up period. Otolaryngol Head Neck Surg 131:514-518, 2004 20. Anderson P, Sindwani R: Safety and efficacy of the endoscopic modified Lothrop procedure: A systematic review and meta-analysis. Laryngoscope 119:1828-1833, 2009