18.1 Introduction

Tumors of the pediatric maxillofacial skeleton are a rare clinical entity with a broad differential diagnosis. ^{1 – 3} Tumors may be classified by origin as being either odontogenic or non-odontogenic or malignant or benign. ⁴ Odontogenic tumors arise from quiescent tooth-forming tissues of the jaws and are most commonly located within the bones of the jaw (central odontogenic tumor), though occasionally they may arise in surrounding soft tissue (peripheral odontogenic tumor). ⁴ The etiology of these tumors remains unknown, and they vary widely in their level of aggression. ⁴ Non-odontogenic tumors encompass a wide range of pathologic conditions and may arise from mesenchymal tissue within the jaw or from the osseous tissue of the jaw. ⁵ No matter the origin, prompt identification and treatment of jaw tumors is critical because some tumors may be either locally destructive or malignant. ^{4 , 6}

The past few decades have shown slow progression from open surgeries to lesser invasive surgery—all in the name of facial esthetics. The initial progress has been the shift from open maxillectomies to facial degloving and the other large step forward was made possible with the advances in endoscopic surgery. Since many tumors are benign, the concept of a non–“En-bloc” resection is feasible and acceptable. Recently, data published from several groups regarding base of skull malignant tumors have shown that a “piecemeal” resection is an acceptable oncologic solution, without compromising survival results. ^{7 – 10}

This chapter is meant to represent and review the various maxillectomies performed nowadays.

18.2 Surgical Approach to Pediatric Maxillectomy

In an open maxillectomy a lateral rhinotomy incision (▶ Fig. 18.1) is commonly used to gain access to the maxillary sinus. ¹¹ If the lesion involves the hard palate, this procedure can be extended to include a lip split also known as a Weber-Ferguson incision (▶ Fig. 18.2).

If there is any difficulty with exposure or if the lesion is located laterally or posteriorly, it is vital to extend the approach to allow better access to the tumor. More complete exposure of the maxilla is obtained by extending the incisions below the lower eyelid. The inferior orbital extension is possible in either a subciliary crease, a midciliary plain, or in an inferior ciliary plain, also known as Diffenbach incision. Another extension of the Lateral Rhinotomy/Weber-Ferguson incision is a Lynch incision that will allow an open approach to the ethmoid sinuses.

The lateral rhinotomy incision extends along the lateral border of the nose, approximately half a cm from the dorsum of the nose. It starts cephalad, medial to the medial canthus and extends down through the skin crest bordering the nasal ala. It is continued toward the philtrum. Following the skin incision, the dissection continues up to the level of the nasal bone and medial buttress of the maxilla. Skin flaps are elevated medially and laterally to the level of the periosteum (▶ Fig. 18.3) with the aid of a freer elevator and electrocautery. Care is taken not to injure the infraorbital nerve, which will be piercing the anterior maxillary wall approximately 1 cm below the infraorbital rim (▶ Fig. 18.4 and ▶ Fig. 18.5). The flaps can be developed to the level of the maxillary tuberosity (laterally), the upper gingiva (inferiorly), the frontal sinus and infraorbital rim (superiorly), and to the pyriform aperture and nasal septum (medially). The flaps are held with hooks.

The osteotomies along the anterior and medial walls of the maxilla are now performed with a motorized reciprocating saw (▶ Fig. 18.6).

The lines of the osteotomies are inferior border of the fossa canina, above the dental roots; superiorly, the orbit; laterally, the malar eminence; and medially the nasal cavity In children, the inferior line is higher than usual, since the second line of teeth does not erupt yet. The medial and part of the anterior wall of the maxilla is now retracted anteriorly with a Babcock’s grasper and the tumor is freed from its attachments with a Mayo scissors and freer elevator. If necessary, the rest of the tissue is extirpated with a Kerrison Rongeur. Hemostasis is performed with 50% hydrogen peroxide and 4 × 4 gauze sponge. The cavity is inspected and hemostasis is completed with bipolar electrocautery. In most cases, branches of the sphenopalatine artery can be identified at the posterior wall of the maxilla, lateral and superior to the choana. These are clamped with medium size clip to prevent further bleeding.

The intraoral mucosal cuts on the palate are made and the periosteum is elevated and bony cuts are made with an oscillating saw. Consistent with disease removal, the incision should be made as far posteriorly in the palate as possible to spare the premaxilla. The premaxilla preserves facial contours and enhances support and stability of the prosthesis. The orbital rim is spared if the orbital contents have not been invaded. The pterygoid plates and the soft tissues of the pterygo-maxillary space are resected or spared according to sound oncological basis but may be resected in an extended maxillectomy. Reconstruction of the surgical defect is achieved with an obturator, soft-tissue free flaps, or bony flaps in case of a large bony defect. We will usually prefer a Scapular-free flap based on the angular branch (tip) of the scapula to reconstruct the maxillary sinus.

Obviously, an intraoral procedure should be considered if the extent of disease is limited and the tumor can be resected with sound oncological principles. Although postoperative healing of a superior cheek flap tends to heal beautifully (▶ Fig. 18.7), it adds to postoperative disfigurement and decreases oral opening.

When the initial incision is made through a tooth socket or diastema, extreme care should be taken to remove the involved permanent tooth buds.

Open approaches to the Maxillary sinus may be combined with a subcranial approach to the base of skull as dictated by surgical needs. ¹² Previous published literature has shown that extirpation of skull base tumors by use of conventional surgical techniques is feasible and safe among infants and children. ¹³ The long-term cosmetic effect of the subcranial approach is negligible. ¹⁴ A comprehensive algorithm for anterior skull base reconstruction after oncological resections was previously described. ^{15 , 16}

18.2.1 Midfacial Degloving

The procedure used was previously described by Maniglia et al ¹⁷ and by Howard and Lund. ¹⁸

The procedure begins with infiltration of 1% Lidocaine and 1:200,000 Adrenaline to the nasal septum, intercartilaginous and sublabial in the area of the columella, and the anterior alveolar process of the maxilla. A sublabial incision is made in the alveolar process of the maxilla about 4 to 6 mm above the teeth from first molar to first molar. This incision can be extended even further back to the third molars if a larger exposure is needed. Bilateral intercartilaginous incisions between the upper and lower lateral cartilages are then made, with full transfixion between the septum and columella. These incisions are extended in order to meet across the floor of the nose permitting elevation of the soft tissues of the dorsum of the nose. Finally, bilateral pyriform aperture incisions are performed to allow the skin and soft tissues of the middle third of the face to be degloved completely. The entire midfacial skin is stripped from the dorsum of the nose and anterior wall of maxilla (▶ Fig. 18.8).

Elevation of the maxillary periosteum and the soft tissues of the cheek allow exposure and preservation of the infraorbital nerves (▶ Fig. 18.9). The elevation is continued till the level of glabella superiorly and medial canthus laterally. The bony nasal pyramid and the attached upper lateral cartilages are exposed completely. Two rubber drains (Penrose type) are passed through the nose and upper lip and are used to retract the midfacial flap along with the upper lip.

Osteotomies are then performed according to the surgical plan. In case of a medial maxillectomy, the procedure begins with removal of the anterior wall of the maxillary sinus (previously described by P. Mallur and G. Har-El). ¹⁹ This is best achieved with Kerrison-Rongeurs with bone removal starting inferomedially and continuing superomedially toward the ethmoid air cells and superolaterally toward the zygomatic arch. Care must be taken to protect and preserve the infraorbital nerve. This is best done by leaving a narrow bony ledge around the infraorbital foramen (▶ Fig. 18.9). Once this is performed, the nasolacrimal sac and duct are addressed. This can be managed by simple transection at the level of the orbital rim, with or without stenting. A cut is made along the nasal bone from the pyriform aperture to the glabella and connected to a posteriorly directed cut along or below and parallel to the frontoethmoidal suture line. The posterior extent of this frontoethmoidal cut is then connected to an oblique cut ending at the orbital rim, medial to the infraorbital foramen. Medial osteotomies are made along the floor of the nasal cavity, separating the lateral nasal wall. Soft-tissue cuts follow each bony osteotomy, freeing the specimen stepwise. The final cut is made with curved osteotomies or heavy curved scissors, freeing the specimen from the posterolateral nasal wall and ascending process of the palatine bone.

This invariably exposes a bleeding sphenopalatine artery, which can be ligated directly.

Alternatively, this can be addressed by ligating the internal maxillary artery in the pterygopalatine fossa after removing the ascending process of the palatine bone. Special consideration can be given to other anatomical areas once the medial maxillectomy is complete. Orbital contents are exposed and the optic nerve may be exposed through systematic drill out toward the optic foramen. The pterygopalatine fossa, infratemporal fossa, and middle cranial fossa skull base can similarly be exposed by removing the posterior and lateral maxilla. Anterior sphenoidotomy can give wide access to the sella turcica and carotid artery. The anterior cranial base can be exposed through middle turbinate excision, though conventional literature supports need for frontal craniotomy or subfrontal approach for “En-bloc” removal of neoplasms encroaching or involving the anterior cranial base.

Traditional limitations for the MFD in accessing the frontal sinus can be overcome by performing ethmoidectomy first and then by detaching the medial canthal tendon to provide additional superiorly based soft-tissue retraction. This maneuver allows complete exposure of the frontal sinus by removing its floor in a posterior-to-anterior direction, starting at the frontal outflow tract. Though rarely needed, an additional exposure can be obtained by removing the anterior frontal sinus wall in an inferomedial-to-superolateral direction. At the conclusion of the extirpative procedure, the maxillectomy cavity is packed with Vaseline gauze strips. Meticulous attention is paid to the previously mentioned intranasal and sublabial incisions. The intranasal incisions are closed with fine absorbable sutures with attention to proper alignment, projection, and rotation (▶ Fig. 18.10). The sublabial incisions can be closed with 3–0 absorbable sutures.

As in open approaches, a combined approach to the base of skull is also feasible. In the classical case of JNAs, a midfacial degloving (▶ Fig. 18.11) can be combined with a subcranial approach effectively for intracranial extensions of this tumor. ^{20 , 21}

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