Key points
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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.
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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.
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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: Caldwell-Luc, external ethmoidectomy, frontal sinus trephine, and osteoplastic flap (OPF).
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: Caldwell-Luc, 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 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.
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. 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 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. 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 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.
The external ethmoidectomy was first discussed by Jansen in 1894 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.”
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.
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. 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 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.
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 Lynch in 1921 and has been extensively modified since that time. The Modified Lynch (Neel-Lake; 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.
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. Stenting the outflow tract is essential. 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. 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.
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