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The safety and effectiveness of the Le Fort I approach to removing central skull base lesions.

Abstract

The difficulty of gaining access to the central skull base has led to the development of many surgical approaches to this area during the past decade. Yet we believe that the Le Fort I technique, which has been used for almost 140 years in orthognathic surgery, is still an excellent approach to treating anterior skull base lesions. This procedure, which entails the horizontal sectioning of the dentoalveolar maxillary segment, seemed to fall out of favor with otolaryngologists after a few reports of complications surfaced during the past 10 to 15 years. In this article, we report a series of seven patients whom we treated with a Le Fort I approach during a 3-year period for a variety of benign and malignant anterior skull base lesions. We have encountered no significant complications of surgery or recurrence of disease at a maximum postoperative followup of 3 years.

Introduction

Despite the remarkable advances we have seen in skull base surgery during the past decade, operating on the central skull base still poses a technical challenge. Access can be gained via transnasal, transpalatal, transoral, transmandibular, and transmaxillary approaches. Often it is necessary to employ a combination of these techniques. [1]

In recent years, a number of patients with anterior skull base lesions have been referred to our center for surgical treatment. One of these patients had already undergone an attempt at removal by other neurosurgical approaches only to experience a recurrence because residual disease had been left in situ as a result of poor access.

In this article, we describe our experience with the Le Fort I osteotomy approach to removing lesions from the central skull base. This is not a new surgical technique. Indeed, it was first described by von Langenbeck in 1861, [2] and it is widely used in orthognathic surgery. However, we have gotten the impression that there is a reluctance by otolaryngologists to utilize this technique because of some reports of significant complications. [3,4] We wish to counter some of the negative associations and highlight the safety and effectiveness of this procedure in approaching these inaccessible lesions.

Patients and methods

Patient characteristics. Between 1996 and 1999, we used the Le Fort I maxillotomy technique to operate on seven patients, aged 28 to 79 years, who had lesions of the anterior skull base (table). One patient (patient 2) had a large clival chordoma that was treated in two stages; the lateral component was resected via an infratemporal fossa approach, and the midline component was removed via the Le Fort I approach some months later (figure 1). Another patient (patient 6) was operated on for a recurrence of a basisphenoid chordoma that had been previously excised via a transnasal approach (figure 2). Two patients were treated for malignancies; patient 1 had a myoepithelial nasopharyngeal carcinoma and received postoperative radiotherapy, and patient 3 had a low-grade sphenoclival chondrosarcoma (figure 3). The other patients had been referred for surgical management after a diagnosis was made based on histologic and radiologic grounds.

Surgical technique. According to our technique, all patients undergo general anesthesia and a tracheostomy. We routinely perform a tracheostomy to ensure airway safety and because it allows for maximal downward displacement of the osteotomized maxilla, which can be limited by an oral endotracheal tube. All patients are given perioperative antibiotic cover with a third-generation cephalosporin. When an intracranial approach is anticipated, we insert a lumbar drain.

Patients are placed in the supine position with varying degrees of head-up tilt for access. We decongest the nose with topical cocaine and inject the sublabial mucosa and nasal mucosa with 1% lidocaine with 1:100,000 adrenaline for hemostasis.

A sublabial incision is made down to the periosteum above the buccogingival sulcus to the maxillary first molars on either side; care is taken to avoid the apical dental roots. The anterior face of the maxilla is exposed by raising a mucoperiosteal flap up to the nasal floor. Holes are drilled prior to the osteotomy to facilitate the accurate placement of mini-plates at the conclusion of the procedure. This enables us to accurately replace the maxilla and prevents the possibility of malocclusion.

An oscillating bone saw is then used to make maxillary osteotomies at the Le Fort I fracture level, from the lateral rim of the nasal aperture through to the pterygomaxillary junction bilaterally (figure 4), thereby sectioning the maxilla horizontally. The nasal septum is lifted off the maxillary crest and vomer with a fine chisel, and the lateral nasal wall is divided with an osteotome. The maxilla is separated from the pterygoid plates behind and can then be downfractured. A modified Dingman's gag can be inserted to keep the mucosa and maxillary segment retracted and afford a clear view of the surgical site. To gain further access posteriorly, we excise the posterior ends of the inferior turbinate and septum. This added exposure allows us to employ a nasal endoscope, operating microscope, ultrasonic aspirator, [CO.sub.2] laser, and/or stereotactic navigational device to good effect.

The tumor is completely removed. If the dura has been breached, the defect is closed with a multilayer of fascia, fat, and human fibrin glue. The maxilla is replaced and plated; the predrilled holes help achieve perfect alignment. We tend to pack the nasal cavity with Kaltostat (calcium sodium alginate), which is removed the following morning. The mucosa is closed with a continuous absorbable suture. The patient is allowed sterile fluids after 24 hours and can progress to a soft diet when able.

Results

Our followup period currently ranges from 9 months to 3 years. We observed no postoperative complications, and all patients experienced rapid wound healing with little discomfort. All patients were successfully decannulated within 5 days of surgery, and all left the hospital 1 week after surgery. There were no problems with malocclusion and no evidence of ischemic necrosis of the maxillary segment. Patient 5 complained of persistent numbness of his upper gum, but he was not overly concerned by this. Also of note is the fact that patient 1 underwent postoperative radiotherapy. Thus far, the radiation has not caused any deleterious effect on the postoperative healing of the maxilla, which had been considered a theoretical risk in the past. Patient 2 died from an unrelated medical condition almost 1 year following surgery.

Discussion

Numerous techniques have been employed to safely access the central skull base. However, many of these approaches put cranial nerves and major vessels at risk. [5] The primary advantages of the Le Fort approach are that it offers good access to the posterosuperior nasopharynx with minimal bone removal (unlike lateral rhinotomy and medial maxillectomy), and it poses no direct risk to major vessels and cranial nerves as long as the surgeon adheres to its boundaries.

Transnasal approaches via anterior facial degloving, alotomy, or lateral rhinotomy are all useful for accessing the anterior nasopharynx, but they are limited in the degree of vertical access they provide to the posterior nasal cavity.

Transpalatal approaches provide direct access to the sphenoid rostrum and proximal clivus, but they require the removal of part of the hard palate and the splitting of the soft palate. They also provide only limited access superiorly.

The transoral route provides direct access to the lower clivus and upper cervical spine, but the nasopharynx is still inaccessible unless the surgeon divides the soft palate, which might cause postoperative fistulae and velopharyngeal incompetence.

The transmandibular or mandibular swing approach to the nasopharynx requires a median mandibulotomy. Although this affords wide access to the clivus and upper cervical spine, it poses a risk to the lingual and hypoglossal nerves. [6] Moreover, oral intake is delayed for up to 1 week after surgery.

Since we began utilizing the Le Fort I approach, we have found it particularly useful for removing lesions of the sphenoid and clivus because it affords a relatively unrestricted access from the sphenoid rostrum to the proximal cervical spine (figure 5). However, we advise caution when employing this approach for extensive intracranial skull base lesions. We believe it is suitable for primarily extradural lesions and for lesions that have breached the dura only minimally.

Crockard has described the use of the Le Fort I approach to basilar artery aneurysms. [5] The lateral limits of this approach are defined by the carotid canals; the IIIrd, IVth, Vth, and VIth cranial nerves; and the venous communications between the cavernous sinuses. To gain better exposure to the lower clivus and upper cervical spine, Catalano et al have used a technique in which the hard palate is split at the midline and hinged laterally on a palatal flap. [1]

The treatment of skull base lesions has been limited by the inaccessibility of the area and the inadequate exposure and close proximity of many significant neural and vascular structures. These limitations have resulted in poor surgical outcomes. [7] The Le Fort I osteotomy can provide up to 8 cm of exposure anteriorly in the horizontal plane and 5 cm posteriorly. [8] This degree of exposure simultaneously offers excellent bilateral visibility and flexibility of access to the posterosuperior nasopharynx.

In our series, we were able to employ a [CO.sub.2] laser, operating microscope, and nasal endoscopes to maximize the complete removal of tumors. Evidence of our success is provided by the fact that we have observed no recurrences thus far.

In conclusion, the Le Fort I osteotomy approach provides a wide exposure of the central skull base for accessing predominantly extradural lesions of the sphenoid, clivus, and upper cervical spine. Our patients have experienced none of the significant postoperative complications that have been previously described. We encourage the use of this approach in appropriately selected patients.

From the Department of Otolaryngology-Head and Neck Surgery, Royal Victorian Eye and Ear Hospital (Dr. Colreavy and Dr. Lyons), the Department of Otolaryngology-Head and Neck Surgery, St. Vincent's Hospital (Dr. Baker and Dr. Lyons), the Department of Otolaryngology-Head and Neck Surgery, Austin Repatriation Hospital (Dr. Campbell), and the Department of Neurosurgery, St. Vincent's Hospital (Dr. Murphy), Melbourne, Australia.

Reprint requests: Dr. M.P. Colreavy, Department of Otolaryngology, The Royal Victorian Eye and Ear Hospital, Adelaide Rd., Dublin 2, Republic of Ireland, Phone: +353-1-678-5500; fax: +353-1-608-3786; e-mail: mcolreavy@hotmail.com

References

(1.) Catalano PJ, Biller HF, Sachev V. Access to the central skull base via a modified Le Fort I maxillotomy: The palatal hinge flap. Skull Base Surgery 1993;3(2):60-8.

(2.) Drommer RB. The history of the "Le Fort I osteotomy." J Maxillofac Surg 1986;14:119-22.

(3.) Lanigan DT, West RA. Management of postoperative hemorrhage following the Le Fort I maxillary osteotomy. J Oral Maxillofac Surg 1984;42:367-75.

(4.) Lanigan DT, Hey JH, West RA. Aseptic necrosis following maxillary osteotomies: Report of 36 cases. J Oral Maxillofac Surg 1990;48:142-56.

(5.) Crockard HA. The transmaxillary approach to the clivus. In: Sekhar LN, Janecka IP, eds. Surgery of Cranial Base Tumors. New York: Raven Press, 1993:235-44.

(6.) Krespi YP, Har-El G. Surgery of the clivus and anterior cervical spine. Arch Otolaryngol Head Neck Surg 1988;114:73-8.

(7.) Nakahira M, Kishimoto S, Miura T, Saito H. Intraosseous hemangioma of the vomer: A case report. Am J Rhinol 1997;11:473-7.

(8.) Sasaki CT, Lowlicht RA, Astrachan DI, et al. Le Fort I osteotomy approach to the skull base. Laryngoscope 1990;100:1073-6.
 Patient characteristics
Pt. Age (yr) Diagnosis Previous surgery Followup
 1 69 Mycepithelial None 2.3 yr
 nasopharyngeal
 carcinoma
 2 79 Clival Infratemporal 1 yr
 chordoma fossa approach
 3 47 Sphenoclival None 3 yr
 chondrosarcoma
 4 28 Clival chordoma None 10 mo
 5 68 Oncocytoma of the None 15 mo
 postnasal space
 6 49 Recurrent Trans-sphenoidal 9 mo
 basisphenoid excision
 chordoma
 7 50 Clival chordoma None 2.5 yr
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Comment:The safety and effectiveness of the Le Fort I approach to removing central skull base lesions.
Author:Lyons, Bernard
Publication:Ear, Nose and Throat Journal
Geographic Code:1USA
Date:May 1, 2001
Words:1952
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