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Long-term Effects of Le Fort I Osteotomy for Resection of Juvenile Nasopharyngeal Angiofibroma on Maxillary Growth and Dental Sensation
Roger A. Lowlicht, DDS;
Basem Jassin, MD;
Michael Kim, DDS;
Clarence T. Sasaki, MD
Arch Otolaryngol Head Neck Surg. 2002;128:923-927.
ABSTRACT
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Objective To analyze the long-term effects of the Le Fort I osteotomy approach
for the resection of juvenile nasopharyngeal angiofibroma (JNA) on maxillary
growth and dental sensation.
Design Prospective collection of structured data.
Setting Tertiary care academic teaching hospital.
Patients Between 1993 and 1998, 5 adolescents (aged 10-14 years) constituted
the evaluable cohort among 14 patients who underwent Le Fort I osteotomy for
JNA resection. Mean follow-up was 47.2 months.
Interventions The Le Fort I osteotomy approach was used to resect JNA. Cephalometric
x-ray films were taken at various postoperative intervals to assess maxillary
growth. The results were matched against age-correlated predictions from Dentofacial
Planner software.
Main Outcome Measures Horizontal and vertical maxillary growth were each measured anteriorly
and posteriorly by comparing interval postoperative cephalometric x-ray films.
Dental sensation was longitudinally evaluated by performing interval pulp
testing postoperatively.
Results (1) Average vertical growth of the maxilla achieved 30% of predicted
growth anteriorly (P = .02). (2) Average horizontal
growth matched predicted growth in all patients. (3) All patients demonstrated
long-term maxillary dental denervation.
Conclusions Le Fort I osteotomy provides excellent surgical exposure for resection
of JNA in the growing facial skeleton. Although it significantly affects vertical
but not horizontal growth, its cosmetic effect is negligible. It also causes
long-term dental denervation, which in most cases is undetected by patients.
INTRODUCTION
THE LE FORT I osteotomy approach can provide an excellent method for
the surgical extirpation of tumors involving the central skull base. The main
advantages of this approach are the wide surgical exposure, the clear visibility
of resection margins, and the lack of superficially visible scars.1
However, it is surprising how little information has been reported about
the effects of this operation on maxillary growth. Normally, vertical growth
of the maxilla occurs at the growth processes located on the attachments of
the frontal and zygomatic bones and on the lower aspect of the alveolar process.2 The growth centers responsible for increasing the
length of the maxilla are located adjacent to the attachment of the palatine
bone and the maxillary tuberosities.3 Growth
spurts of the maxilla occur between 10 and 12 years in girls and between 12
and 14 years in boys.4 However, this growth
can continue into adulthood.5
Another consequence of a Le Fort I osteotomy is the potential loss of
dental sensory function. With this approach, the infraorbital nerve is spared.
However, the nasopalatine nerve, and the anterior, middle, and posterior superior
alveolar nerves are cut.6 In addition, the
greater palatine nerve may be disrupted from manipulation of the maxilla to
increase surgical visualization. Although the Le Fort osteotomy is designed
to avoid denervation of the soft tissues of the face, denervation of the teeth
may be unavoidable.
The purpose of our study was to analyze the effects of Le Fort I osteotomy
on the growth of the maxilla and on the long-term sensation of the teeth.
PATIENTS AND METHODS
This study involved 5 boys aged 10 to 14 years constituting the evaluable
cohort identified among 14 patients undergoing a Le Fort I osteotomy for the
resection of juvenile nasopharyngeal angiofibroma (JNA) between 1993 and 1998
at Yale–New Haven Hospital, New Haven, Conn (Figure 1). Because the age period of greatest maxillary growth is
from 8 to 16 years,8 we limited our study to
patients in this age group, thus excluding 9 of 14 patients older than 16
years. The mean follow-up was 47.2 months. Preoperative embolization of the
tumor feeding vessels was carried out in all patients. All operations were
performed by 2 of us (C.T.S. and R.A.L.). The surgical technique involved
sacrifice of the greater palatine arteries, application of rigid titanium
fixation in all cases, and removal of impacted third molars. Maxillomandibular
fixation was not applied postoperatively. All the patients had class I occlusion.
One patient had preoperative and postoperative orthodontic therapy and another
had postoperative orthodontic therapy.
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Figure 1. A, Degloving exposure of the maxilla;
B, down fracture of the maxillary arch; and C, manner of 4-point fixation.
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CEPHALOMETRY
Each patient had a reference lateral cephalometric x-ray film taken
in a Weimer head frame at 90 kilovolt peak (kVp)/0.1125 milliampere second
(mAs) within 1 week after surgery. The film was then repeated at a future
interval varying from 8 to 108 months postoperatively. Each cephalogram was
digitized by one of us (M.K.). Each image contained 66 points of data that
were entered into Dentofacial Planner software (Dentofacial Software Inc,
Toronto, Ontario). This software constructs a growth estimate curve for the
location of the maxilla based on the age of the patient at the time of surgery,
immediate postoperative skeletal landmarks, and the interval period.
The cephalometric growth data were analyzed in the following fashion.
An axis was created parallel to the Frankfort horizontal and perpendicular
to the Frankfort horizontal (Figure 2).
The Frankfort horizontal is the distance from the superior aspect of the external
auditory meatus (porion) to the inferior aspect of the orbital rim (the orbitale).
Horizontal growth of the maxilla in an anterior fashion was defined as a positive
right change along the x-axis. Vertical growth was defined as positive down
change along the y-axis. The points to define maxillary position were the
anterior nasal spine (ANS) and the posterior nasal spine (PNS). The ANS was
defined as the point at which the anterior process reached a thickness of
3 mm, while the PNS was defined as the posterior end point of the hard palate
(Figure 2).
Thus, spatial movement as a function of time of ANS defined anterior
growth, and spatial movement as a function of time of PNS defined posterior
growth. We then compared the actual growth of the maxilla as a percentage
of growth predicted by the Dentofacial Planner software. The average of the
actual growth was compared with the average predicted growth and the results
were analyzed for statistical significance using a paired t test.
PULP TESTING TECHNIQUE
In the first week after surgery, the entire maxillary and mandibular
dentition were tested electrically for pulp sensation using a monopolar Digitest
Pulp Vitality Tester (model D626D; Parkell Electronics Division, Farmingdale,
NY). The measurement technique used a constant current of 150 µA, as
described previously by Matthews and Searle.7
Because surrounding soft tissue moisture contamination can introduce inaccuracies
in pulp test data, each tooth tested was isolated from the saliva with soft
tissue retraction, cotton rolls, and air drying. Current was applied incrementally
until the patient was able to identify a stimulus. This test was then longitudinally
repeated at a postoperative interval varying from 8 to 108 months postoperatively.
RESULTS
CEPHALOMETRIC MEASUREMENTS
Table 1 summarizes the results
of our study. For each patient, the follow-up interval is shown along with
the actual measured maxillary growth and the predicted maxillary growth. The
"S" point indicates the starting position of the ANS or PNS of the patient,
as demonstrated in the cephalometric x-ray film taken 1 week after surgery.
The "F" point indicates the final position of the ANS or PNS of the patient,
as shown in the final cephalometric x-ray film taken at the indicated postoperative
interval for each patient. The "P" point indicates the predicted position
of the ANS or PNS of the patient, as shown in the cephalometric construct
made for the patient from the Dentofacial Planner software. Thus, the distance
S to F is the actual interval, and the distance S
to P is the predicted interval growth. Based on historical
data,8 all of the patients should have experienced
adolescent growth during the interval.
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Table 1. Cephalometric Data*
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For example, Table 1 shows
that for patient 2, the horizontal growth of the maxilla (along the x-axis)
is presented in the ANS (X) column. The ANS point moved 1 mm in the horizontal
direction from the starting point to the finishing point (S-F distance). The
predicted movement of the ANS point (S-P) was 1 mm. It appears that at 16
months postoperatively, this patient had exhibited predicted maxillary growth
in the horizontal direction.
The vertical growth of the anterior maxilla (along the y-axis) is presented
in the ANS-Y column. For patient 2, ANS moved 0 mm (S-F measurement). The
predicted movement of the ANS point (S-P measurement) was 2 mm. Thus, there
was 0% of predicted anterior maxillary vertical growth at 16 months postoperatively.
Similar results were obtained by analyzing the movement of the PNS point in
the PNS-X and PNS-Y columns.
Table 1 also summarizes
the average growth data for all patients. It appears that all patients grew
100% of the predicted growth along the horizontal axis, ie, ANS (X) and PNS
(X) are shown as 100% of predicted. However, growth of the maxilla along the
vertical axis was not as complete. The average vertical growth of our patients
along the anterior maxilla (as described in the ANS-Y column) was 30% of the
predicted growth. This result was found to be statistically significant compared
with the average expected growth using a paired t
test (P = .02). For the posterior maxillary segment
(PNS-Y), the average vertical growth was 27% of the predicted growth. This
result was not found to be statistically significant (P = .06). Interestingly, the reduction in vertical maxillary growth
was largely subjectively unnoticed in our patient cohort.
PULP TESTING
In all patients, there was no evidence of sensation as recorded by electrical
stimulation to all the maxillary teeth at the postoperative interval period.
However, pinprick sensation was intact in the adjacent palatal mucosa, and
dental numbness went largely unnoticed. These results are summarized in Table 2.
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Table 2. Pulp Testing Data
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COMMENT
Although there are numerous studies of the effects of plating in long
bone growth, few specifically address the growth effect across maxillary suture
lines. There are 2 studies on the effect of Le Fort I osteotomies on maxillary
growth. However, both of these studies were made on patients undergoing surgical
repositioning of the maxilla for correction of dentofacial deformities. A
1997 study showed normal maxillary growth in patients undergoing a Le Fort
I osteotomy for excessive vertical maxillary growth.9
In addition, these patients underwent concomitant orthodontic therapy. The
method of evaluation involved measurement of the presurgical and postsurgical
spatial change in ANS and PNS in a lateral cephalogram. The surgical group
was compared with unoperated-on matched controls from a data bank similar
to that of the Dentofacial Planner software. The mean age of the patients
was 14.5 years and the mean postsurgical follow-up was 25 months. In our study
only 2 of the 5 patients underwent postsurgical orthodontics, and our mean
follow-up was 47.2 months.
An earlier study that had examined the maxillary growth of subjects
(aged 13-17 years) who had undergone surgical repositioning of the maxilla
with interosseous wiring and intermaxillary fixation found that there was
an increase of the vertical dimension of the maxilla after surgery.10 However, no comparison with a control group was made.
Patients in our series differed from patients in previous studies in that
rigid fixation plates across the horizontal osteotomy were used to stabilize
the maxilla. Because JNA is located posterior to the maxilla, it is unlikely
that the growth of the tumor played a role in disturbing maxillary growth
centers. We believe the effect on vertical maxillary growth is therefore surgically
related.
All of our patients exhibited denervation of the maxillary teeth in
the long-term postoperative period. However, a study by Al-Din et al11 that looked at the sensory nerve disturbances that
occur after Le Fort I osteotomy showed contrasting results. They reported
that of patients who had a positive response to an electric pulp tester preoperatively,
78% regained sensitivity to pulp testing after 6 months. Other studies of
sensation in teeth following Le Fort I osteotomy also indicate that there
are no long-term sensory sequelae in the teeth after this procedure. A study
by De Jongh and coworkers12 in 1986 compared
electric pulp testing of 10 patients after Le Fort I osteotomy with 10 matched
controls who did not have any surgery. He found that 14 months after surgery,
71% of the teeth tested were responsive to electric pulp stimulation. The
figure in the control group was 93%. Other studies by Kahnberg and Engstrom13 and Tajima14 also
demonstrated that most patients who underwent Le Fort I osteotomy recovered
teeth sensation to pulp testing 6 to 18 months after surgery. In contrast,
all the patients in our study showed long-term dental denervation following
the Le Fort I osteotomy—explained in part by our necessity to section
both anterior and posterior superior alveolar nerves.
In examining palatal sensation, Al-Din et al11
found that the return of fine touch and pinprick sensation of the palate was
affected by whether the greater palatine nerve was divided during surgery.
That all of the patients in our study were able to regain pinprick sensation
in the postoperative period confirms this explanation since palatine nerves
were stretched by the down fracture but anatomically preserved.
CONCLUSIONS
Despite the important advantages of surgical exposure, the clear visibility
of resection margins, and the avoidance of visible facial scars, the Le Fort
I osteotomy approach comes with certain postoperative consequences. This study
demonstrates that patients who undergo Le Fort I osteotomy for JNA resection
have long-term dental denervation, although, for the most part, this was unnoticed
by our patients. These results contrast to those of previous studies in patients
undergoing Le Fort I osteotomy for skeletal repositioning (orthognathics).
We also confirm that Le Fort I osteotomy performed with metal rigid
fixation is unlikely to have an impact on horizontal maxillary growth. However,
we demonstrate that there is a statistically significant decrease of anterior
vertical maxillary growth. As all of our patients developed a functional occlusion,
this effect was not clinically significant, nor was the effect on vertical
maxillary growth noticeable to the patients or their parents.
AUTHOR INFORMATION
Accepted for publication January 9, 2002.
This study was supported in part by the McFadden Endowment, the Harmon
Endowment, and the Mirikitani Endowment.
This study was presented at the Eastern Section meeting of the Triological
Society, Pittsburgh, Pa, January 29, 2000.
Corresponding author: Roger A. Lowlicht, DDS, 185 Maple Ave, North
Haven, CT 06473.
From the Department of Surgery, Section of Otolaryngology, Yale School
of Medicine (Drs Lowlicht and Sasaki), and the Department of Otolaryngology,
Yale–New Haven Medical Center (Dr Jassin), New Haven, Conn. Dr Kim is
in private practice in Hamden, Conn.
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X, distance of horizontal growth of the maxilla; and