Transcript Document

The effect of the alar base cinch suture in the treatment of Le Fort 1 osteotomy
patients -a pilot study using a prospective randomised controlled trial study design
Caitriona Howley, Shirley Cox
Results
Background
The Le Fort 1 osteotomy is a versatile procedure used to correct
a variety of dentofacial deformities of the maxilla. The
procedure is associated with unfavourable nasolabial soft tissue
changes including widening of the alar base width of the nose.
The alar base cinch suture was initially advocated to correct
nasal defects associated with cleft lip deformities (Millard,
1980). It was later modified for use in non-cleft patients by
Collins and Epker (1982). The authors proposed that it would:•Control the width of the alar base of the nose
•Create increased fullness of the subnasal area
•Slightly increase the length of the upper lip
The Le Fort 1 osteotomy caused an increase in the alar base
width of the nose in all participants at six months post surgery.
Alar base width
Median
Subjects and Method
B. Excluded (n=1 )
-Did not meet inclusion criteria (n=1)
-Refused to participate (n=0)
-Other Reasons (n=0)
C. Randomised (n=21)
D (i). Randomly allocated to
intervention A (n=11)
-Received intervention A (n=11)
-Did not receive intervention A
(n=0)
D (ii). Randomly allocated to
intervention B (n=10)
-Received intervention B (n=10)
-Did not received intervention B
(n=0)
E (i). Lost to follow up (n=0)
-Discontinued intervention (n=0)
E (ii). Lost to follow up (n=0)
-Discontinued intervention (n=0)
F (i). Analysed (n=10)
Excluded from analyses (n=1) as
treatment was performed
outside the time interval for the
study’s conduct
F (ii). Analysed (n=10)
Excluded from analyses (n=0)
Figure 1. Flow diagram of participant’s progress through the
stages of this pilot study
Total
1.6
2.1
2
A-B
B-D
D-E
C-F
F-G
H-K
I-J
G-L
M-N
The primary aim of this pilot study is to develop and pilot
methods for a prospective randomised controlled trial to
investigate the effect of an alar base cinch suture on the
change in the alar base width of the nose following a Le Fort 1
osteotomy procedure.
A. Assessment for eligibility (n=22 )
Control
1.7
3.3
2.3
Interquartile Range
Table 1. Changes in the alar base width in millimetres, from
baseline to 6 month post surgery
Aim
The pilot study adopted a prospective randomised controlled
trial study design in accordance with CONSORT guidelines;
(Consolidated Standards of Reporting Trials, Altman et al., 2001).
In the intervention group (intervention A) an alar base cinch
suture was placed, in the control group (intervention B) it was
not. A standardised surgical technique was used. The change
in alar base width was determined post-operatively with the use
of a three-dimensional imaging system (an optical surface laser
scanner).
The inclusion criteria were, patients:
•16 years and older
•requiring a Le Fort 1 osteotomy with an anterior or superior
vector of maxillary movement
•wearing fixed appliances with size 0.019 x 0.025 inch stainless
steel archwires in the upper and lower dental arches
Cinch
Right eye width
Intercanthal width
Left eye width
Nasion to pronasale
Height of nasal base
Greatest alar width
Alar base width
Upper lip length
Commisural width
Figure 2 and Table 2. Landmarks
measured on the laser scan and
definition of inter-landmark
measurements respectively
The placement of an alar base cinch suture in participants
appears to lead to slightly less widening of the alar base width
of the nose, when compared to participants who did not have
an alar base cinch suture placed at surgery. The median
difference observed was small (0.5mm) which may suggest that
the placement of an alar base cinch suture may not be
relevant in clinical terms.
The range of changes in the alar base width however was
large, particularly in the control group of patients.
Conclusions
The main conclusions of this pilot study are:
•Preliminary results of 20 patients suggest minimal difference in
the alar base width of the nose in the control and intervention
groups. This needs to be confirmed in a study based on a larger
sample of patients.
•Agreement of the surgeons to follow a standardised surgical
procedure in the performance of a Le Fort 1 osteotomy has
been obtained.
•The optical surface laser scanning ‘mark and measure’ system
has been shown to be a valid and reproducible method of
quantifying nasolabial soft tissue changes associated with the
Le Fort 1 osteotomy.
•Methods for a randomised controlled trial have been
developed.
References
Millard, D.R. Jr. (1980) The alar cinch in the flat flaring nose.
Plastic and Reconstructive Surgery 65: 669-672
Collins, P.C. and Epker, B.N. (1982)
The alar base cinch: A technique for prevention of alar base
flaring secondary to maxillary surgery.
Oral Surgery, Oral Medicine, Oral Pathology 53: 549-553
Altman, D.G., et al (2001) The Revised CONSORT Statement for
Reporting Randomised Trials: Explanation and Elaboration.
Annals of Internal Medicine 134: 663-694
Betts, N.J., et al(1993) Changes in the nasal and labial soft
tissues after surgical repositioning of the maxilla.
International Journal of Orthognathic Surgery 8: 7-23
Bell, W.H. (1975) Le Fort 1 osteotomy for correction of maxillary
deformities.
Journal of Oral Surgery 33: 412-426
*Contact details: [email protected]