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Early Practice
Early Practice External Sinus Surgery and Procedures and Complications John S. Schneider, MD, MAa,*, Andrew Day, MDa, Matthew Clavena, MDb, Paul T. Russell III, MDb, James Duncavage, MDb KEYWORDS Caldwell-Luc approach External ethmoidectomy Frontal trephine Osteoplastic flap KEY POINTS The anterior, inferior portion of the maxillary sinus may harbor diseased tissue that cannot be addressed medically and may be difficult to access endoscopically. In this situation, a Caldwell-Luc approach may be necessary. External ethmoidectomy, while rarely used, can be useful when pathology inhibits proper visualization from the endoscopic approach. One MUST be mindful of orbital injury in this procedure. External approaches to the frontal sinus require identification of the most superior aspect of the sinus and the relative position of the posterior table in the anterior-posterior dimension (including relative changes in that dimension from superior to inferior).
INTRODUCTION
External approaches to the paranasal sinuses are rarely performed in the endoscopic era. However, they remain important surgical options in some cases. In this article, the indications, techniques, and complications of 4 techniques are described: CaldwellLuc, external ethmoidectomy, frontal sinus trephine, and osteoplastic flap (OPF). MAXILLARY SINUS
The maxillary sinus can be the most difficult sinus to manage medically and surgically in select patients. Endoscopic access to all regions of the maxillary sinus, including the most anterior, inferior, and lateral portions of the sinus, requires that endoscopes and
a Department of Otolaryngology, Washington University in St. Louis, 660 South Euclid Avenue, Campus Box 8115, St Louis, MO 63110, USA; b Department of Otolaryngology, Vanderbilt University, 2201, West End Avenue, Nashville, TN 37235, USA * Corresponding author. E-mail address: [email protected]
Otolaryngol Clin N Am - (2015) -–http://dx.doi.org/10.1016/j.otc.2015.05.010 0030-6665/15/$ – see front matter Ó 2015 Elsevier Inc. All rights reserved.
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instruments are able to pivot and reach around the pyriform aperture and nasolacrimal duct. However, this may not be possible in all cases. The external approach to the maxillary sinus can provide the sinus surgeon the ability to surgically remove diseased tissue or neoplastic processes that cannot be reached even by extended endoscopic approaches. The open surgical approach to the maxillary sinus is described in classic Caldwell-Luc articles.1 The authors approach for the Caldwell-Luc procedure is as follows. A gingivolabial incision is made through the mucosa and periosteum of the canine fossa (Figs. 1 and 2). Careful periosteal elevation is performed over the anterior maxilla up to the level of the infraorbital nerve. The first assistant uses the maxillary retractors to hold the mucoperiosteum off the maxilla as the surgeon elevates it. The maxillary sinus is entered with a sinus trocar, rotating the trocar; direct force, such as a mallet, is not used.2 A 3-mm Kerrison punch is used to widen the opening created by the trocar. Care is taken to maintain the lateral maxillary buttress. The anterior wall opening is widened as necessary for the particular procedure as required (Fig. 3). This opening ranges from an opening just wide enough to accommodate an endoscope for resections of pterygopalatine fossa lesions to a wide opening to accommodate endoscopes and instruments for maxillary sinus tissue removal in inverted papilloma cases. Closure consists of deep sutures of the soft tissue directly overlying the maxillary sinus wall defect, typically with Vicryl suture. The gingivolabial mucosa is then closed with absorbable suture, such as chromic or Vicryl. Complications can be divided into intraoperative and postoperative complications. The most troublesome intraoperative complication of note is bleeding from the pterygopalatine or infratemporal fossa, including branches of the sphenopalatine artery (SPA). This bleeding can occur when too much force is used to initiate the anterior wall defect with the trocar. If the trocar penetrates the infratemporal fossa, the artery is at risk. Thus, it is stressed that one must use the twisting technique to enter the sinus instead of the mallet use technique. If bleeding is minor, bipolar or suction cautery may be used for control. In the authors’ experience, SPA ligation has never been required; however, it must be considered for bleeding that cannot be controlled. Postoperatively, the most concerning complication to the patient is poor wound healing. Poor wound healing must be managed expectantly; however, one must account for possible infection arising in the maxillary sinus itself. Long-term poor wound healing can result in an oroantral fistula through the anterior maxillary wall defect requiring additional procedures to close. Numbness of the infraorbital nerve can also occur. If careful attention is not paid to the position of the nerve preoperatively, injury can occur without intraoperative awareness. It is typically managed by watchful expectancy, assuming that the surgeon has not transected the nerve. Of note, in
Fig. 1. Caldwell-Luc: sublabial approach.
External Sinus Surgery
Fig. 2. Caldwell-Luc: exposure of anterior maxillary wall.
patients requiring a Caldwell-Luc for recalcitrant chronic rhinosinusitis, special considerations must be made. The patient is informed that the Caldwell-Luc procedure is approximately 90% successful.3 The other 10% may need a second procedure to marsupialize a maxillary sinus mucocele that may develop years later. ETHMOID SINUS
The most common contemporary indications for ethmoid surgery include chronic inflammatory disease refractory to medical therapy and acute infection with orbital complications. The endoscopic transnasal ethmoidectomy has become the near exclusive approach over the last 25 years. However, the external approach may be useful in a
Fig. 3. Caldwell-Luc: exposure of maxillary sinus.
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few selected cases, including increased exposure to ethmoid and orbital tumors as well as simple ligation of the anterior and posterior ethmoid arteries for control of epistaxis. However, the control of epistaxis may be more easily approached by the transcaruncular approach, which provides similar exposure but no visible scars.4 The external ethmoidectomy was first discussed by Jansen in 18945 and has been modified repeatedly since that time. The approach allows for exposure of the ethmoid sinuses, medial orbit, and anterior skull base. Minor modifications allow for exposure of the frontal recess, superior-medial orbit, sphenoid, and orbital apex. The modern external ethmoidectomy is approached via a modified Lynch incision (Fig. 4). The incision starts at the inferior border of the medial aspect of the eyebrow and is carried inferiorly in a curvilinear fashion between the medial canthus and the glabella. The incision is carried down to the level of the periosteum at the medial orbit (Fig. 5). Hemostasis is easily achieved inferiorly with bipolar cautery of the distal branches of the angular artery. Care is taken superiorly to preserve to the supratrochlear neurovascular bundle. Once this has been accomplished, the orbital contents are carefully lateralized using elevators, taking care to preserve the periorbita. Approximately 24 mm posterior to the anterior lacrimal crest, the anterior ethmoid artery is encountered and may be ligated with bipolar cautery or clips. Approximately 12 mm beyond the anterior ethmoid, the posterior ethmoid artery will be encountered and is likewise ligated. Approximately 6 mm beyond the posterior ethmoid lies the optic nerve, which should not be disturbed. This relationship is best known as the “24/12/6 Rule.”6 Once vascular control is completed, the lamina papyracea is resected, allowing access to the entire ethmoid cavity (Fig. 6). The ethmoid contents may then be exenterated in a complete fashion. Closure of the modified lynch incision is performed in layers with the periosteum and subcutanenous tissues closed first with absorbable suture and a plastics closure made on the skin.5 The complications associated with this approach are inherent to its technique and can be broken down to perioperative and postoperative in nature. Perioperatively, inadequate control of the ethmoidal arteries may lead to significant postoperative hemorrhage with the possibility of blindness secondary to retrobulbar hematoma. Direct injury to the optic nerve is a possibility if the dissection in the orbit is not mindfully performed.2 Damage to the periorbita during surgery is not a direct problem, but the resulting spillage of orbital fat may lead to great difficulties in visualization. Poor visualization may thereby lead to surgical misadventure. The medial rectus lies just inside the periorbita and may be easily injured if great care is not exercised. Profuse bleeding may occur if the medial aspect of the anterior ethoidectomy is
Fig. 4. External ethmoidectomy: incision plan.
External Sinus Surgery
Fig. 5. External ethmoidectomy: exposure of periosteum.
encountered at the inferior posterior aspect of the frontal recess. Skull-base injury with cerebrospinal rhinorrhea is possible medially at the fovea ethmoidalis. Resultant repair may be quite challenging from an external approach. Postoperatively, the modified lynch incision may make a cosmetically unacceptable scar. This scar may be more noticeable with the wider, flatter nasal bridge associated with various ethnic and racial groups. Forehead hypoesthesia is possible with damage to the supratrochlear neurovascular bundle. Overresection of the medial orbit anteriorly may lead to telocanthus because the medial canthus is disrupted and displaced laterally. This displacement may lead to lacrimal system injury and epiphora as well, if the resection is carried out too far inferiorly. Furthermore, the resultant bony contour of the incision site may retract, leading to poor cosmetic outcome. Although the entire lamina papyracea may be removed, it is advisable to leave the superior aspect intact. Leaving the superior aspect intact will help prevent the overmedicalization of orbital contents despite an intact periorbita, resulting in obstruction of the frontal recess. The external approach, however, is less refined than the endoscopic approach, and preserving the mucosal lining in the ethmoids is more challenging. Resulting scarring may then become more robust, causing secondary problems. Scarring at the middle meatus is a concern because it lies nearly perpendicular to the plane of dissection and cannot be easily visualized.
Fig. 6. External ethmoidectomy: exposure of ethmoid sinus.
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Frontal Recess
External approaches to the frontal recess are largely extensions to the external ethmoidectomy. These approaches are historically fraught with failure and along with the ethmoidectomy have been essentially abandoned to the endoscopic approach. Although no absolute indications for these approaches currently exist for sinus disease, they may be of help in certain circumstances, such as encountered with the external ethmoid approaches, and trauma to the naso-orbito-ethmoid complex. The nonobliterative external frontal recess procedure was described by Lynch7 in 1921 and has been extensively modified since that time. The Modified Lynch (NeelLake; 1976) and the Sewall-Boyden (1973) procedure have been described. These procedures allow for the opening of the frontal recess; the later modifications were proposed to prevent the very high restenosis rates.8,9 The approach begins as the external ethmoidectomy. After performing said operation, the Modified Lynch procedure enters the frontal sinus at the superomedial angle of the orbit.8 Stenting the outflow tract is essential.7 The modification from the original involves preserving more of the superior bone to prevent overmedialization of the orbital contents. Also, mucosa sparing was introduced and various flaps were used to attempt to preserve some normal function. The last major development in the attempt to preserve outflow tract function from an external approach was arguably the Sewall-Boyden flap.9 Although never a particularly popular technique, much of its philosophy was later incorporated into the current methods of frontal sinus surgery. These current methods include preservation of function with mucosal preservation and minimally traumatic disruption of tissues. The complications of the external frontal sinus approaches are essentially the same as the external ethmoid approaches. Failures occur at the frontal recess with restenosis of the outflow tract. This complication has unfortunately not been resolved in the endoscopic era as well. FRONTAL SINUS
Complex frontal sinus anatomy remains a challenge for sinus surgeons. Despite advances in image-guided instruments, variable frontal sinus anatomy can create challenges when approaching the sinus intranasally. A narrow frontal recess, type 4 frontal cells, and pathologic abnormality in the lateral or superior aspects of the sinus can often remain out of reach for endoscopic frontal instruments.10–12 In addition, neoosteogenesis of the frontal recess, previous trauma, severe frontal recess stenosis, and frontal bone osteomyelitis may necessitate an external approach.12 Two open techniques, frontal sinus trephination and the OPF, remain viable adjuncts to endoscopic sinus surgery for the frontal sinus. These techniques are described in later discussion. Frontal Sinus Trephination
The authors perform a frontal sinus trephine as an adjunct to endonasal techniques only if the target region is not accessible via standard endoscopic approaches. The forehead is prepared and the medial brow is injected with 1% lidocaine with epinephrine 1:100,000. A 0.5- to 1-cm incision is made approximately 1 to 1.5 cm from the midline at the inferomedial margin of the brow or within the brow (Fig. 7). If the incision is placed within the brow, the blade should be beveled parallel to the hair follicles to avoid eyebrow alopecia and a better cosmetic result. The soft tissues are gently dissected sparing the supratrochlear and supraorbital neurovascular bundles until the frontal bone is exposed. The periosteum is dissected off the bone and the location for the trephine marked.
External Sinus Surgery
Fig. 7. Frontal trephine: incision plan.
The location of the frontal sinus trephine is variable and dependent on the individual aeration pattern of the frontal sinus. Traditional teaching recommends performing it close to the floor of the sinus about 1 to 1.5 cm from the midline where the depth of the frontal sinus is the greatest, thus minimizing the risk of posterior table penetration. Lee and colleagues13 recently measured the depth of the frontal sinus at 0.5, 1.0, and 1.5 cm from the midline and found no statistically significant difference in measurements. Lee did find an increased risk of cross-trephination when performed 0.5 cm from midline because of the variable location of the intersinus septum. Imageguided surgery is commonly used in when addressing the frontal sinus endoscopically, but it can also be used to locate the safest area for the trephine. Image guidance trephination offers several advantages over blind entry in that it can specifically localize the target lesion, minimizes the size of the skin incision and trephination, and lowers the risk of intracranial entry. Before the advent of image guidance, a template of the frontal sinus was made from the 6-ft. Caldwell-view radiograph. The authors prefer to use image guidance to localize the site for the trephine. Once localized, a 4-mm burr is used to drill the anterior table and enter the frontal sinus in an area that is strategic and will provide the greatest access to the disease (Fig. 8). Kerrison rongeurs can be used to enlarge the opening if needed for simultaneous placement of the endoscope and instruments. Endoscopes are introduced through the trephine, and the sinus cavity and drainage pathway are evaluated. Instruments are inserted through the trephine, and the pathologic abnormality is removed (Fig. 9). If the frontal recess anatomy is distorted, cannulating or irrigating through the trephine while visualizing the recess endonasally may find the opening to the frontal sinus. A frontal sinus stent may be placed through the trephine or endoscopically. External drainage of the frontal sinus in severe frontal infections is also possible through the trephine. For closure, the periosteum is approximated with absorbable sutures, and the skin incision is sutured typically with fast gut suture. Complications from frontal sinus trephination are rare and typically minor. The first complication is external scar formation. There should be gentle soft tissue manipulation, and the trephine should not be larger than 0.5 cm to avoid soft tissue prolapse
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Fig. 8. Frontal trephine: trephine.
and poor cosmetic results.14 Other minor complications have been reported like facial cellulitis and wound infection.15 Supratrochlear nerve injury is rare, but can be very troubling to the patient. Patients must be counseled regarding the risk of forehead numbness, and that it often can only be observed, with no definitive therapy. More serious complications are violation of the posterior table, cerebrospinal fluid (CSF) leak, and orbital injury. Posterior table violation can be avoided if proper image guidance is used, and choking up on the drill to ensure that once the anterior table has been breached, the drill does not proceed toward the posterior table. Choking up also minimizes the likelihood of CSF leak. Orbital injury is possible; however, with image guidance, this risk is reduced significantly. Careful planning in the 3-dimensional plane will help avoid inadvertent orbital injury. The surgeon must be aware not only of the placement of the entry point on the anterior table but also of the trajectory of the drill such that it remains in a central location in the most aerated area of the frontal sinus; this avoids the most superior aspect of the medial orbital wall and orbital roof (lateral border), the intrasinus septum (medial border), frontal recess (inferior border), and the top of the frontal sinus (superior border). Frontal Osteoplastic Flap
The OPF was first reported in 1894 by Schonborn and described in detail by Hoffman in 1904.16 This approach allows access to the frontal sinus to treat an arrangement of
Fig. 9. Frontal trephine: frontoethmoid track.
External Sinus Surgery
disease problems from sinusitis to malignancies as long as the posterior table is uninvolved. The OPF may be performed in conjunction with or without sinus obliteration that was later popularized in the 1950s to 1960s by Goodale and Montgomery,17–19 resulting in the removal of the entirety of the frontal sinus mucosa, which is then filled with biologically compatible material to scar by secondary intent. As endoscopic techniques addressing frontal sinus disease have advanced, including the modified endoscopic Lothrop, OPF and especially, obliterative techniques have become increasingly uncommon. Despite this, external approaches still play a role in a rhinologist’s armament for disease not completely accessible through or refractory to endoscopic approaches, mostly secondary to neo-osteogenesis of the frontal recess.12 In order to perform an OPF, an incision must be chosen to gain access to the frontal bone. The most common incision made to perform an OPF is the bicoronal incision, less commonly a gull-wing or lateral brow incision is used for reasons discussed later. Once an incision of choice is made to gain access to the frontal sinus (Fig. 10), a 6-ft Caldwell radiograph template of the sinus, or more commonly, image guidance is used to make guide holes to give a template, followed by bony cuts of the anterior table (OPF) (Fig. 11). If sinus obliteration is performed, all the mucosa is stripped and then burred with a drill, to ensure even microscopic remains of mucosa are removed (Fig. 12). The frontal outflow tract is then plugged (usually with muscle) and the sinus is filled, most commonly with fat (hydroxyapatite is another alternative, although fallen in favor), usually taken from the abdomen. Closure requires placing the OPF back in place, with or without hardware fixation, followed by skin closure. This approach has lost favor for many reasons, primarily because of the comorbidity of the procedure, length of time, and secondary complications, primarily associated with OPF with sinus obliteration. Revision rates for OPF either with the external approach alone or with a combination of endoscopy has a revision rate near 24%.12 Complications from OPF will vary depending on specific incision used, size or extent of frontal pneumatization, disease treated, and reason for obliteration. Complications related to the skin incision to gain exposure to the frontal bone are minimized by fundamental surgical techniques. In order to expose the frontal bone to perform an OPF necessitates a large incision that can result in poor cosmetic outcomes. One of the easiest ways to minimize poor cosmesis is to perform the incision in hair-bearing area, thus camouflaging the scar by hair. For limited disease, brow incisions are performed for unilateral access, and a gull-wing in bilateral, connecting the incisions over the glabella. The gull-wing can often leave a noticeable scar, especially in the glabellar region due to lack of hair, and thus with patients having intact hair at the
Fig. 10. OPF: bone cut plan.
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Fig. 11. OPF: superior bone cut.
scalp, the bicoronal incision is chosen. This approach hides the scar in the scalp hair; however, injury to facial nerves (temporal branch) and supraorbital nerves can result in facial weakness and numbness to scalp, respectively. Furthermore, nonlinear incisions (eg, sinusoidal and weaving linear lines) are well described to help decrease appearance in the scalp. When placing an incision in a hair-bearing region, meticulous detail must be made to avoid damage to the hair follicles, as described above. Avoiding damage to the hair follicles is especially important in brow incisions. Avoiding facial nerve injury when raising a bicoronal skin flap is performed by staying in the proper dissection plane, which should be just deep to the temporoparietal fascial, just above the deep temporal fascia, resulting in the facial nerve being dissected superficially and thus protecting it. Preventing damage to the supraorbital neurovascular bundle, which results in unnecessary numbness to the forehead and scalp, is first minimized by properly identifying the neurovascular bundle during the dissection. Removing the inferior bony lip of the foramen with an osteotome can ensure further protection; thus allowing the nerves and vessels more degrees of freedom as the flap is rotated inferiorly. The same technique can be used to protect the trochlear neurovascular bundle if the dissection is carried more inferiorly. To note, numbness results to areas posterior to the incision site; regardless, though, these tend to improve with time. Raising the OPF itself can result in exposure of orbital fat, unintentional fracture of the anterior frontal wall, and damage to structures around the sinus as mentioned
Fig. 12. OPF: anterior displacement of bone flap.
External Sinus Surgery
later. Bony wound closure can also result in cosmetic problems with either frontal bossing or depression secondary to the OPF not healing flush with surrounding bone. These cosmetic problems are thought to happen primarily either by improper technique or from the removal of bone during sawing around the edge of the flap. Intracranial and intraorbital complications are the most feared. Orbital fat exposure is typically seen with drilling of the superior orbit. Intracranial complications are seen with dural laceration and intracranial breech, resulting in CSF leaks. These leaks usually result from inadequate understanding of the frontal sinus pneumatization, and the degree of which can make this more or less complicated. Intracranial injury is best avoided by using either a Caldwell 6-ft radiographic film (as mentioned above), transillumination of the sinus either transnasally (endoscopic) or transcutaneously (trephination), or image guidance (most common practice currently). Bony healing problems with the OPF can result in cosmetic deformities. But this can be mitigated by meticulous care in placing the OPF such that it is properly oriented and flush on all edges. Minimizing bone loss during bony flap harvest is described by using an angled (30 ) oscillating saw or wire drill instead a standard burred drill. Furthermore, a form of fibrin glue instead of plates and screws should be used to prevent hardware extrusion or infection; however, if unstable, internal fixation should be performed.20,21 The most common long-term complication of frontal sinus obliteration after OPF is mucocele formation. Mucocele formation, along with advancements in endoscopic instrumentation and techniques, has pushed the treatment of frontal sinus disease endoscopically. The reported time range of postoperative mucocele formation from sinus obliteration is 1 to 42 years after surgery, with the mean time around 7 to 8 years. The most common location of mucocele formation is the frontal recess,22 which can arise from residual mucosa in the sinus or pneumatization of the obliterated sinus from the ethmoid cells. Avoidance of mucocele formation is best done by ensuring even microscopic residual mucosa is removed. Besides meticulous care to remove all of the mucosa, using a drill burr to polish the entirety of the cavity will help remove residual microscopic mucosa, especially in the frontal recess region, because this is the most common location of failure. Moreover, if complete mucosal obliteration is not possible, this procedure should not be undertaken secondary to a high risk of mucocele formation. Postoperative management of complications associated with OPF of the frontal sinuses is somewhat limited, because access to the sinus for evaluation under indirect visualization (endoscopy) is not feasible. Monitoring the sinus after obliteration or manipulation of frontal recess with imaging has minimal utility, because mucocele formation may result as late as 42 years later,22 and thus clinical assessment and judgment are key. When there is frontal mucocele or frontal infection, such as infection of fat, an unobliteration procedure is recommended.12,20 An unobliteration procedure involves connecting the mucosalized cavity with the functional outflow tract. An unobliteration procedure can be done by either a modified endoscopic Lothrop procedure (Draf III) or a frontal sinusotomy procedure, attempting to preserve as much mucosa as possible. Because of the high recurrence rates from unobliteration secondary to scarring of re-created outflow tract, stents are often left in place for extended periods of time.21,22 SUMMARY
External approaches to the maxillary, ethmoid, and frontal sinuses remain an important component of the sinus surgeon’s tool box. Even as endoscopic approaches continue to evolve, the variation in sinus anatomy and disease processes can create challenges to endoscopic access. It is hoped that this article helps to explain the techniques and complications that may arise from open approaches.
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REFERENCES
1. Macbeth R. Caldwell, Luc, and their operation. Laryngoscope 1971;81(10): 1652–7. 2. Robinson S, Wormald PJ. Patterns of innervation of the anterior maxilla: a cadaver study with relevance to canine fossa puncture of the maxillary sinus. Laryngoscope 2005;115(10):1785–8. 3. Cutler JL, Duncavage JA, Matheny K, et al. Results of Caldwell-Luc after failed endoscopic middle meatus antrostomy in patients with chronic sinusitis. Laryngoscope 2003;113(12):2148–50. 4. Balch K, Goldberg R, Green J, et al. The transcaruncular approach to the medial orbit and ethmoid sinus. Facial Plast Surg Clin North Am 1998;6:71–7. 5. Smith F. Chronic sinus disease: its present status. JAMA 1933;100(6):402. 6. Rontal E, Rontal M, Guilford FT. Surgical anatomy of the orbit. Ann Otol Rhinol Laryngol 1979;88(3 Pt 1):382–6. 7. Lynch RC. The technique of a radical frontal sinus operation which has given me the best results. Laryngoscope 1921;31:1. 8. Neel HB, McDonald TJ, Facer GW. Modified Lynch procedure for chronic frontal sinus diseases: rationale, technique, and long-term results. Laryngoscope 1987; 97(11):1274–9. 9. Baron SH, Dedo HH, Henry CR. The mucoperiosteal flap in frontal sinus surgery. (The Sewall-Boyden-McNaught operation). Laryngoscope 1973;83(8):1266–80. 10. Benoit CM, Duncavage JA. Combined external and endoscopic frontal sinusotomy with stent placement: a retrospective review. Laryngoscope 2001;111(7):1246–9. 11. Walgama E, Ahn C, Batra PS. Surgical management of frontal sinus inverted papilloma: a systematic review. Laryngoscope 2012;122(6):1205–9. 12. Hahn S, Palmer JN, Purkey MT, et al. Indications for external frontal sinus procedures for inflammatory sinus disease. Am J Rhinol Allergy 2009;23(3):342–7. 13. Lee A, Schaitkin B, Gillman G. Evaluating the safety of frontal sinus trephination. Laryngoscope 2010;120:639–42. 14. Bent JP, Spears RA, Kuhn FA, et al. Combined endoscopic intranasal and external frontal sinusotomy. Am J Rhinol 1997;11(5):349–54. 15. Batra PS, Citardi MJ, Lanza DC. Combined endoscopic trephination and endoscopic frontal sinusotomy for management of complex frontal sinus pathology. Am J Rhinol 2005;19(5):435–41. 16. Hoffman R. Osteoplastic operations on the frontal sinuses for chronic suppuration. Ann Otol Rhinol Laryngol 1904;13:598–608. 17. Goodale RL, Montgomery WW. Anterior osteoplastic frontal sinus operation. Five years’ experience. Ann Otol Rhinol Laryngol 1961;70:860–80. 18. Goodale RL, Montgomery WW. Technical advances in osteoplastic frontal sinusectomy. Arch Otolaryngol 1964;79:522–9. 19. Guggenheim P. Indications and methods for performance of osteoplasticobliterative frontal sinusotomy with a description of a new method and some remarks upon the present state of the are of external frontal sinus surgery. Laryngoscope 1981;91(6):927–38. 20. Healy DY, Leopold DA, Gray ST, et al. The perforation technique: a modification to the frontal sinus osteoplastic flap. Laryngoscope 2014;124(6):1314–7. 21. Isa AY, Mennie J, McGarry GW. The frontal osteoplastic flap: does it still have a place in rhinological surgery? J Laryngol Otol 2011;125(2):162–8. 22. Javer AR, Alandejani T. Prevention and management of complications in frontal sinus surgery. Otolaryngol Clin North Am 2010;43(4):827–38.
INTRODUCTION
External approaches to the paranasal sinuses are rarely performed in the endoscopic era. However, they remain important surgical options in some cases. In this article, the indications, techniques, and complications of 4 techniques are described: CaldwellLuc, external ethmoidectomy, frontal sinus trephine, and osteoplastic flap (OPF). MAXILLARY SINUS
The maxillary sinus can be the most difficult sinus to manage medically and surgically in select patients. Endoscopic access to all regions of the maxillary sinus, including the most anterior, inferior, and lateral portions of the sinus, requires that endoscopes and
a Department of Otolaryngology, Washington University in St. Louis, 660 South Euclid Avenue, Campus Box 8115, St Louis, MO 63110, USA; b Department of Otolaryngology, Vanderbilt University, 2201, West End Avenue, Nashville, TN 37235, USA * Corresponding author. E-mail address: [email protected]
Otolaryngol Clin N Am - (2015) -–http://dx.doi.org/10.1016/j.otc.2015.05.010 0030-6665/15/$ – see front matter Ó 2015 Elsevier Inc. All rights reserved.
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instruments are able to pivot and reach around the pyriform aperture and nasolacrimal duct. However, this may not be possible in all cases. The external approach to the maxillary sinus can provide the sinus surgeon the ability to surgically remove diseased tissue or neoplastic processes that cannot be reached even by extended endoscopic approaches. The open surgical approach to the maxillary sinus is described in classic Caldwell-Luc articles.1 The authors approach for the Caldwell-Luc procedure is as follows. A gingivolabial incision is made through the mucosa and periosteum of the canine fossa (Figs. 1 and 2). Careful periosteal elevation is performed over the anterior maxilla up to the level of the infraorbital nerve. The first assistant uses the maxillary retractors to hold the mucoperiosteum off the maxilla as the surgeon elevates it. The maxillary sinus is entered with a sinus trocar, rotating the trocar; direct force, such as a mallet, is not used.2 A 3-mm Kerrison punch is used to widen the opening created by the trocar. Care is taken to maintain the lateral maxillary buttress. The anterior wall opening is widened as necessary for the particular procedure as required (Fig. 3). This opening ranges from an opening just wide enough to accommodate an endoscope for resections of pterygopalatine fossa lesions to a wide opening to accommodate endoscopes and instruments for maxillary sinus tissue removal in inverted papilloma cases. Closure consists of deep sutures of the soft tissue directly overlying the maxillary sinus wall defect, typically with Vicryl suture. The gingivolabial mucosa is then closed with absorbable suture, such as chromic or Vicryl. Complications can be divided into intraoperative and postoperative complications. The most troublesome intraoperative complication of note is bleeding from the pterygopalatine or infratemporal fossa, including branches of the sphenopalatine artery (SPA). This bleeding can occur when too much force is used to initiate the anterior wall defect with the trocar. If the trocar penetrates the infratemporal fossa, the artery is at risk. Thus, it is stressed that one must use the twisting technique to enter the sinus instead of the mallet use technique. If bleeding is minor, bipolar or suction cautery may be used for control. In the authors’ experience, SPA ligation has never been required; however, it must be considered for bleeding that cannot be controlled. Postoperatively, the most concerning complication to the patient is poor wound healing. Poor wound healing must be managed expectantly; however, one must account for possible infection arising in the maxillary sinus itself. Long-term poor wound healing can result in an oroantral fistula through the anterior maxillary wall defect requiring additional procedures to close. Numbness of the infraorbital nerve can also occur. If careful attention is not paid to the position of the nerve preoperatively, injury can occur without intraoperative awareness. It is typically managed by watchful expectancy, assuming that the surgeon has not transected the nerve. Of note, in
Fig. 1. Caldwell-Luc: sublabial approach.
External Sinus Surgery
Fig. 2. Caldwell-Luc: exposure of anterior maxillary wall.
patients requiring a Caldwell-Luc for recalcitrant chronic rhinosinusitis, special considerations must be made. The patient is informed that the Caldwell-Luc procedure is approximately 90% successful.3 The other 10% may need a second procedure to marsupialize a maxillary sinus mucocele that may develop years later. ETHMOID SINUS
The most common contemporary indications for ethmoid surgery include chronic inflammatory disease refractory to medical therapy and acute infection with orbital complications. The endoscopic transnasal ethmoidectomy has become the near exclusive approach over the last 25 years. However, the external approach may be useful in a
Fig. 3. Caldwell-Luc: exposure of maxillary sinus.
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few selected cases, including increased exposure to ethmoid and orbital tumors as well as simple ligation of the anterior and posterior ethmoid arteries for control of epistaxis. However, the control of epistaxis may be more easily approached by the transcaruncular approach, which provides similar exposure but no visible scars.4 The external ethmoidectomy was first discussed by Jansen in 18945 and has been modified repeatedly since that time. The approach allows for exposure of the ethmoid sinuses, medial orbit, and anterior skull base. Minor modifications allow for exposure of the frontal recess, superior-medial orbit, sphenoid, and orbital apex. The modern external ethmoidectomy is approached via a modified Lynch incision (Fig. 4). The incision starts at the inferior border of the medial aspect of the eyebrow and is carried inferiorly in a curvilinear fashion between the medial canthus and the glabella. The incision is carried down to the level of the periosteum at the medial orbit (Fig. 5). Hemostasis is easily achieved inferiorly with bipolar cautery of the distal branches of the angular artery. Care is taken superiorly to preserve to the supratrochlear neurovascular bundle. Once this has been accomplished, the orbital contents are carefully lateralized using elevators, taking care to preserve the periorbita. Approximately 24 mm posterior to the anterior lacrimal crest, the anterior ethmoid artery is encountered and may be ligated with bipolar cautery or clips. Approximately 12 mm beyond the anterior ethmoid, the posterior ethmoid artery will be encountered and is likewise ligated. Approximately 6 mm beyond the posterior ethmoid lies the optic nerve, which should not be disturbed. This relationship is best known as the “24/12/6 Rule.”6 Once vascular control is completed, the lamina papyracea is resected, allowing access to the entire ethmoid cavity (Fig. 6). The ethmoid contents may then be exenterated in a complete fashion. Closure of the modified lynch incision is performed in layers with the periosteum and subcutanenous tissues closed first with absorbable suture and a plastics closure made on the skin.5 The complications associated with this approach are inherent to its technique and can be broken down to perioperative and postoperative in nature. Perioperatively, inadequate control of the ethmoidal arteries may lead to significant postoperative hemorrhage with the possibility of blindness secondary to retrobulbar hematoma. Direct injury to the optic nerve is a possibility if the dissection in the orbit is not mindfully performed.2 Damage to the periorbita during surgery is not a direct problem, but the resulting spillage of orbital fat may lead to great difficulties in visualization. Poor visualization may thereby lead to surgical misadventure. The medial rectus lies just inside the periorbita and may be easily injured if great care is not exercised. Profuse bleeding may occur if the medial aspect of the anterior ethoidectomy is
Fig. 4. External ethmoidectomy: incision plan.
External Sinus Surgery
Fig. 5. External ethmoidectomy: exposure of periosteum.
encountered at the inferior posterior aspect of the frontal recess. Skull-base injury with cerebrospinal rhinorrhea is possible medially at the fovea ethmoidalis. Resultant repair may be quite challenging from an external approach. Postoperatively, the modified lynch incision may make a cosmetically unacceptable scar. This scar may be more noticeable with the wider, flatter nasal bridge associated with various ethnic and racial groups. Forehead hypoesthesia is possible with damage to the supratrochlear neurovascular bundle. Overresection of the medial orbit anteriorly may lead to telocanthus because the medial canthus is disrupted and displaced laterally. This displacement may lead to lacrimal system injury and epiphora as well, if the resection is carried out too far inferiorly. Furthermore, the resultant bony contour of the incision site may retract, leading to poor cosmetic outcome. Although the entire lamina papyracea may be removed, it is advisable to leave the superior aspect intact. Leaving the superior aspect intact will help prevent the overmedicalization of orbital contents despite an intact periorbita, resulting in obstruction of the frontal recess. The external approach, however, is less refined than the endoscopic approach, and preserving the mucosal lining in the ethmoids is more challenging. Resulting scarring may then become more robust, causing secondary problems. Scarring at the middle meatus is a concern because it lies nearly perpendicular to the plane of dissection and cannot be easily visualized.
Fig. 6. External ethmoidectomy: exposure of ethmoid sinus.
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Frontal Recess
External approaches to the frontal recess are largely extensions to the external ethmoidectomy. These approaches are historically fraught with failure and along with the ethmoidectomy have been essentially abandoned to the endoscopic approach. Although no absolute indications for these approaches currently exist for sinus disease, they may be of help in certain circumstances, such as encountered with the external ethmoid approaches, and trauma to the naso-orbito-ethmoid complex. The nonobliterative external frontal recess procedure was described by Lynch7 in 1921 and has been extensively modified since that time. The Modified Lynch (NeelLake; 1976) and the Sewall-Boyden (1973) procedure have been described. These procedures allow for the opening of the frontal recess; the later modifications were proposed to prevent the very high restenosis rates.8,9 The approach begins as the external ethmoidectomy. After performing said operation, the Modified Lynch procedure enters the frontal sinus at the superomedial angle of the orbit.8 Stenting the outflow tract is essential.7 The modification from the original involves preserving more of the superior bone to prevent overmedialization of the orbital contents. Also, mucosa sparing was introduced and various flaps were used to attempt to preserve some normal function. The last major development in the attempt to preserve outflow tract function from an external approach was arguably the Sewall-Boyden flap.9 Although never a particularly popular technique, much of its philosophy was later incorporated into the current methods of frontal sinus surgery. These current methods include preservation of function with mucosal preservation and minimally traumatic disruption of tissues. The complications of the external frontal sinus approaches are essentially the same as the external ethmoid approaches. Failures occur at the frontal recess with restenosis of the outflow tract. This complication has unfortunately not been resolved in the endoscopic era as well. FRONTAL SINUS
Complex frontal sinus anatomy remains a challenge for sinus surgeons. Despite advances in image-guided instruments, variable frontal sinus anatomy can create challenges when approaching the sinus intranasally. A narrow frontal recess, type 4 frontal cells, and pathologic abnormality in the lateral or superior aspects of the sinus can often remain out of reach for endoscopic frontal instruments.10–12 In addition, neoosteogenesis of the frontal recess, previous trauma, severe frontal recess stenosis, and frontal bone osteomyelitis may necessitate an external approach.12 Two open techniques, frontal sinus trephination and the OPF, remain viable adjuncts to endoscopic sinus surgery for the frontal sinus. These techniques are described in later discussion. Frontal Sinus Trephination
The authors perform a frontal sinus trephine as an adjunct to endonasal techniques only if the target region is not accessible via standard endoscopic approaches. The forehead is prepared and the medial brow is injected with 1% lidocaine with epinephrine 1:100,000. A 0.5- to 1-cm incision is made approximately 1 to 1.5 cm from the midline at the inferomedial margin of the brow or within the brow (Fig. 7). If the incision is placed within the brow, the blade should be beveled parallel to the hair follicles to avoid eyebrow alopecia and a better cosmetic result. The soft tissues are gently dissected sparing the supratrochlear and supraorbital neurovascular bundles until the frontal bone is exposed. The periosteum is dissected off the bone and the location for the trephine marked.
External Sinus Surgery
Fig. 7. Frontal trephine: incision plan.
The location of the frontal sinus trephine is variable and dependent on the individual aeration pattern of the frontal sinus. Traditional teaching recommends performing it close to the floor of the sinus about 1 to 1.5 cm from the midline where the depth of the frontal sinus is the greatest, thus minimizing the risk of posterior table penetration. Lee and colleagues13 recently measured the depth of the frontal sinus at 0.5, 1.0, and 1.5 cm from the midline and found no statistically significant difference in measurements. Lee did find an increased risk of cross-trephination when performed 0.5 cm from midline because of the variable location of the intersinus septum. Imageguided surgery is commonly used in when addressing the frontal sinus endoscopically, but it can also be used to locate the safest area for the trephine. Image guidance trephination offers several advantages over blind entry in that it can specifically localize the target lesion, minimizes the size of the skin incision and trephination, and lowers the risk of intracranial entry. Before the advent of image guidance, a template of the frontal sinus was made from the 6-ft. Caldwell-view radiograph. The authors prefer to use image guidance to localize the site for the trephine. Once localized, a 4-mm burr is used to drill the anterior table and enter the frontal sinus in an area that is strategic and will provide the greatest access to the disease (Fig. 8). Kerrison rongeurs can be used to enlarge the opening if needed for simultaneous placement of the endoscope and instruments. Endoscopes are introduced through the trephine, and the sinus cavity and drainage pathway are evaluated. Instruments are inserted through the trephine, and the pathologic abnormality is removed (Fig. 9). If the frontal recess anatomy is distorted, cannulating or irrigating through the trephine while visualizing the recess endonasally may find the opening to the frontal sinus. A frontal sinus stent may be placed through the trephine or endoscopically. External drainage of the frontal sinus in severe frontal infections is also possible through the trephine. For closure, the periosteum is approximated with absorbable sutures, and the skin incision is sutured typically with fast gut suture. Complications from frontal sinus trephination are rare and typically minor. The first complication is external scar formation. There should be gentle soft tissue manipulation, and the trephine should not be larger than 0.5 cm to avoid soft tissue prolapse
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Fig. 8. Frontal trephine: trephine.
and poor cosmetic results.14 Other minor complications have been reported like facial cellulitis and wound infection.15 Supratrochlear nerve injury is rare, but can be very troubling to the patient. Patients must be counseled regarding the risk of forehead numbness, and that it often can only be observed, with no definitive therapy. More serious complications are violation of the posterior table, cerebrospinal fluid (CSF) leak, and orbital injury. Posterior table violation can be avoided if proper image guidance is used, and choking up on the drill to ensure that once the anterior table has been breached, the drill does not proceed toward the posterior table. Choking up also minimizes the likelihood of CSF leak. Orbital injury is possible; however, with image guidance, this risk is reduced significantly. Careful planning in the 3-dimensional plane will help avoid inadvertent orbital injury. The surgeon must be aware not only of the placement of the entry point on the anterior table but also of the trajectory of the drill such that it remains in a central location in the most aerated area of the frontal sinus; this avoids the most superior aspect of the medial orbital wall and orbital roof (lateral border), the intrasinus septum (medial border), frontal recess (inferior border), and the top of the frontal sinus (superior border). Frontal Osteoplastic Flap
The OPF was first reported in 1894 by Schonborn and described in detail by Hoffman in 1904.16 This approach allows access to the frontal sinus to treat an arrangement of
Fig. 9. Frontal trephine: frontoethmoid track.
External Sinus Surgery
disease problems from sinusitis to malignancies as long as the posterior table is uninvolved. The OPF may be performed in conjunction with or without sinus obliteration that was later popularized in the 1950s to 1960s by Goodale and Montgomery,17–19 resulting in the removal of the entirety of the frontal sinus mucosa, which is then filled with biologically compatible material to scar by secondary intent. As endoscopic techniques addressing frontal sinus disease have advanced, including the modified endoscopic Lothrop, OPF and especially, obliterative techniques have become increasingly uncommon. Despite this, external approaches still play a role in a rhinologist’s armament for disease not completely accessible through or refractory to endoscopic approaches, mostly secondary to neo-osteogenesis of the frontal recess.12 In order to perform an OPF, an incision must be chosen to gain access to the frontal bone. The most common incision made to perform an OPF is the bicoronal incision, less commonly a gull-wing or lateral brow incision is used for reasons discussed later. Once an incision of choice is made to gain access to the frontal sinus (Fig. 10), a 6-ft Caldwell radiograph template of the sinus, or more commonly, image guidance is used to make guide holes to give a template, followed by bony cuts of the anterior table (OPF) (Fig. 11). If sinus obliteration is performed, all the mucosa is stripped and then burred with a drill, to ensure even microscopic remains of mucosa are removed (Fig. 12). The frontal outflow tract is then plugged (usually with muscle) and the sinus is filled, most commonly with fat (hydroxyapatite is another alternative, although fallen in favor), usually taken from the abdomen. Closure requires placing the OPF back in place, with or without hardware fixation, followed by skin closure. This approach has lost favor for many reasons, primarily because of the comorbidity of the procedure, length of time, and secondary complications, primarily associated with OPF with sinus obliteration. Revision rates for OPF either with the external approach alone or with a combination of endoscopy has a revision rate near 24%.12 Complications from OPF will vary depending on specific incision used, size or extent of frontal pneumatization, disease treated, and reason for obliteration. Complications related to the skin incision to gain exposure to the frontal bone are minimized by fundamental surgical techniques. In order to expose the frontal bone to perform an OPF necessitates a large incision that can result in poor cosmetic outcomes. One of the easiest ways to minimize poor cosmesis is to perform the incision in hair-bearing area, thus camouflaging the scar by hair. For limited disease, brow incisions are performed for unilateral access, and a gull-wing in bilateral, connecting the incisions over the glabella. The gull-wing can often leave a noticeable scar, especially in the glabellar region due to lack of hair, and thus with patients having intact hair at the
Fig. 10. OPF: bone cut plan.
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Fig. 11. OPF: superior bone cut.
scalp, the bicoronal incision is chosen. This approach hides the scar in the scalp hair; however, injury to facial nerves (temporal branch) and supraorbital nerves can result in facial weakness and numbness to scalp, respectively. Furthermore, nonlinear incisions (eg, sinusoidal and weaving linear lines) are well described to help decrease appearance in the scalp. When placing an incision in a hair-bearing region, meticulous detail must be made to avoid damage to the hair follicles, as described above. Avoiding damage to the hair follicles is especially important in brow incisions. Avoiding facial nerve injury when raising a bicoronal skin flap is performed by staying in the proper dissection plane, which should be just deep to the temporoparietal fascial, just above the deep temporal fascia, resulting in the facial nerve being dissected superficially and thus protecting it. Preventing damage to the supraorbital neurovascular bundle, which results in unnecessary numbness to the forehead and scalp, is first minimized by properly identifying the neurovascular bundle during the dissection. Removing the inferior bony lip of the foramen with an osteotome can ensure further protection; thus allowing the nerves and vessels more degrees of freedom as the flap is rotated inferiorly. The same technique can be used to protect the trochlear neurovascular bundle if the dissection is carried more inferiorly. To note, numbness results to areas posterior to the incision site; regardless, though, these tend to improve with time. Raising the OPF itself can result in exposure of orbital fat, unintentional fracture of the anterior frontal wall, and damage to structures around the sinus as mentioned
Fig. 12. OPF: anterior displacement of bone flap.
External Sinus Surgery
later. Bony wound closure can also result in cosmetic problems with either frontal bossing or depression secondary to the OPF not healing flush with surrounding bone. These cosmetic problems are thought to happen primarily either by improper technique or from the removal of bone during sawing around the edge of the flap. Intracranial and intraorbital complications are the most feared. Orbital fat exposure is typically seen with drilling of the superior orbit. Intracranial complications are seen with dural laceration and intracranial breech, resulting in CSF leaks. These leaks usually result from inadequate understanding of the frontal sinus pneumatization, and the degree of which can make this more or less complicated. Intracranial injury is best avoided by using either a Caldwell 6-ft radiographic film (as mentioned above), transillumination of the sinus either transnasally (endoscopic) or transcutaneously (trephination), or image guidance (most common practice currently). Bony healing problems with the OPF can result in cosmetic deformities. But this can be mitigated by meticulous care in placing the OPF such that it is properly oriented and flush on all edges. Minimizing bone loss during bony flap harvest is described by using an angled (30 ) oscillating saw or wire drill instead a standard burred drill. Furthermore, a form of fibrin glue instead of plates and screws should be used to prevent hardware extrusion or infection; however, if unstable, internal fixation should be performed.20,21 The most common long-term complication of frontal sinus obliteration after OPF is mucocele formation. Mucocele formation, along with advancements in endoscopic instrumentation and techniques, has pushed the treatment of frontal sinus disease endoscopically. The reported time range of postoperative mucocele formation from sinus obliteration is 1 to 42 years after surgery, with the mean time around 7 to 8 years. The most common location of mucocele formation is the frontal recess,22 which can arise from residual mucosa in the sinus or pneumatization of the obliterated sinus from the ethmoid cells. Avoidance of mucocele formation is best done by ensuring even microscopic residual mucosa is removed. Besides meticulous care to remove all of the mucosa, using a drill burr to polish the entirety of the cavity will help remove residual microscopic mucosa, especially in the frontal recess region, because this is the most common location of failure. Moreover, if complete mucosal obliteration is not possible, this procedure should not be undertaken secondary to a high risk of mucocele formation. Postoperative management of complications associated with OPF of the frontal sinuses is somewhat limited, because access to the sinus for evaluation under indirect visualization (endoscopy) is not feasible. Monitoring the sinus after obliteration or manipulation of frontal recess with imaging has minimal utility, because mucocele formation may result as late as 42 years later,22 and thus clinical assessment and judgment are key. When there is frontal mucocele or frontal infection, such as infection of fat, an unobliteration procedure is recommended.12,20 An unobliteration procedure involves connecting the mucosalized cavity with the functional outflow tract. An unobliteration procedure can be done by either a modified endoscopic Lothrop procedure (Draf III) or a frontal sinusotomy procedure, attempting to preserve as much mucosa as possible. Because of the high recurrence rates from unobliteration secondary to scarring of re-created outflow tract, stents are often left in place for extended periods of time.21,22 SUMMARY
External approaches to the maxillary, ethmoid, and frontal sinuses remain an important component of the sinus surgeon’s tool box. Even as endoscopic approaches continue to evolve, the variation in sinus anatomy and disease processes can create challenges to endoscopic access. It is hoped that this article helps to explain the techniques and complications that may arise from open approaches.
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