Cephalometric evaluation after two-stage palatoplasty combined with a Hotz plate: a comparative study between the modified Furlow and Widmaier–Perko methods

Abstract

The effects on craniofacial growth of two different soft palate repair techniques in two-stage palatoplasty were investigated. This was a retrospective, cross-sectional cohort study of 68 children with non-syndromic, complete unilateral cleft lip and palate. Thirty-four patients were treated with the modified Furlow method (F-group) and the remaining 34 with the Widmaier–Perko method (P-group). Craniofacial growth was assessed by analyzing 12 angular and 12 linear measurements on lateral cephalograms. Composite facial diagrams from the two groups were compared with those of a control non-cleft group. Angular and linear measurements did not differ significantly between the two groups, implying that the craniofacial morphology was not affected by the difference in soft palate repair technique. However, small differences in anterior nasal spine and posterior nasal spine were found in cleft patients compared with controls. These findings suggest that the modified Furlow and Widmaier–Perko methods have a similar impact on craniofacial growth. Considering speech function, the modified Furlow method provides better craniofacial growth and speech function. However, the long-term effects of both methods on craniofacial growth after growth cessation remain to be determined.

The craniofacial region is important for many functions, such as eating, chewing, swallowing, and speaking. It is also important from an aesthetic standpoint. Patients with unilateral cleft lip and palate (UCLP) require interdisciplinary team management and longitudinal follow-up from birth to ensure adequate craniofacial function and satisfactory facial morphology.

Functional and morphological disruption of the craniofacial region by UCLP can lead to a speech impediment caused by velopharyngeal insufficiency, nasal deformity, retardation of maxillary growth, and dental arch distortion. Successful treatment of these disorders depends upon the surgeon’s skill and the timing and method of the surgical repair. In recent years, protocols have been established in each hospital to minimize these problems, and maxillary growth and speech have reportedly been improved. However, these protocols could be improved further.

At Niigata University Graduate School of Medical and Dental Sciences, a two-stage palatoplasty combined with a Hotz plate (the Zürich University protocol ) was used to treat UCLP beginning in 1983. Although adequate craniofacial growth was reported using this approach, speech development was found to be delayed by several years. To address this, the soft palate repair technique was changed from the Widmaier–Perko method to a modified Furlow method in 1996, which led to better velopharyngeal function. Velopharyngeal function improved earlier using the modified Furlow method, and the speech outcome was similar to that using the one-stage push-back palatoplasty protocol.

A characteristic of the two-stage palatoplasty is minimal invasion of the maxillary bone until hard palate closure. This means that the change in protocol probably had little influence on craniofacial growth. However, data regarding the effects of the different soft palate repair methods on maxillary growth remain limited and are restricted to the use of dental casts; no data have been published using cephalograms. In this study, the effects on craniofacial growth of two different soft palate repair techniques in two-stage palatoplasty were investigated.

Materials and methods

Patients

Sixty-eight healthy, non-syndromic children with complete UCLP and no mental retardation were included in this retrospective study. They were divided into two groups based on the treatment protocol used ( Figs 1 and 2 ): (1) the F-group comprised 34 children (15 female and 19 male), born between 1994 and 2004, with a mean age at the time of cephalogram of 84.4 ± 6.4 months; these children underwent soft palate repair by modified Furlow method; (2) the P-group comprised 34 children (10 female and 24 male), born between 1983 and 1993, with a mean age at the time of cephalogram of 86.3 ± 6.2 months; these children underwent soft palate repair by Widmaier–Perko method.

Fig. 1
Modified Furlow method for two-stage palatoplasty. (A) Incision lines: the solid line for the oral layer and the dotted line for the nasal layer. (B) Flap dissection in the oral layer: the posterior left-sided flap contains the veli palatini muscle. (C) Opposite Z-plasty design of the nasal layer: the posterior right-sided flap also contains the veli palatini muscle; the muscles are redirected from an oblique vertical to an oblique horizontal position, are posteriorly repositioned, and overlap to make a muscle sling. (D) Closure of the oral layer.

Fig. 2
Widmaier–Perko method for two-stage palatoplasty. (A) Submucosal flap dissection in the oral layer: the triangular design at the anterior border of the soft palate allows backward V–Y elongation later on. (B) Repair of the nasal layer. (C) End-to-end reconstruction of the veli palatini muscles to make a muscle sling after separating the muscle stumps from the hard palate and oral and nasal layers. (D) Closure of the oral layer.

Participants in both groups were treated with a two-stage palatoplasty in combination with a Hotz plate. The Hotz plate was used from the early postnatal period to aid in feeding and for early maxillary orthopaedics. The cleft lip was repaired in both groups using the Cronin technique at an average age of 6 months. The cleft size of the posterior edge of the hard palate was an average of 9.9 mm in the F-group and 10.5 mm in the P-group before soft palate repair ( Table 1 ). The soft palate repair was performed at a mean age of 18 months in the F-group and 19 months in the P-group. All patients wore a palatal plate to cover the residual hard palate cleft until hard palate closure. The hard palate was closed using a Pichler vomer mucoperiosteal flap (mean age 67 months for the F-group and 72 months for the P-group). These surgeries were performed by six veteran surgeons (A, B, C, D, E, and F) for lip repair (F-group: surgeon A n = 15, surgeon B n = 19; P-group: surgeon A n = 34), soft palate repair (F-group: surgeon A n = 10, surgeon B n = 21, surgeon C n = 3; P-group: surgeon A n = 33, surgeon C n = 1), and hard palate closure (F-group: surgeon B n = 8, surgeon D n = 16, surgeon E n = 9, surgeon F n = 1; P-group: surgeon A n = 10, surgeon B n = 22, surgeon C n = 2); ‘ n ’ represent the number of cases performed.

Table 1
Distribution of the cleft and the cleft size at soft palate repair.
Mean (mm) SD Range (mm)
F-group a ( n = 34) 9.9 1.7
Right ( n = 14) 10.0 1.4 9–12
Left ( n = 20) 9.9 2.0 7–13
P-group a ( n = 34) 10.5 2.2
Right ( n = 8) 11.1 2.3 8–13
Left ( n = 26) 10.3 2.1 4–14

SD, standard deviation.

a F-group: modified Furlow method; P-group: Widmaier–Perko method.

The sample size required for this study was estimated. The effect size was assumed to be medium ( d = 0.5), the α -level was set at 5% ( α = 0.05), and the statistical power was estimated to be 80% (1 − β = 0.8). The required sample size was estimated to be 64 in both groups. However, the number of subjects satisfying the inclusion criteria was insufficient to meet this target of 64 subjects for each group; this is a limitation of the retrospective study design. In particular, additional subjects could not be included in the P-group as the Widmaier–Perko method was not used after 1996. This study was approved by the University Faculty of Dentistry Ethics Committee and was performed in compliance with the principles stated in the Declaration of Helsinki.

Lateral cephalometric analysis

In the orthodontic clinic of the study hospital, the management of patients with UCLP generally starts from 5 years of age. Cephalograms are obtained at the first visit, before the first- and second-phase orthodontic treatment, and after these treatments.

Lateral cephalograms performed before the first phase of orthodontic treatment and secondary alveolar bone grafting were used to measure the effects of soft palate repair on craniofacial growth in this study (F-group: mean age 84.4 ± 6.4 (range 72–94) months; P-group: mean age 86.3 ± 6.2 (range 73–95) months). All cephalograms were performed for orthodontic diagnostic purposes before the onset of the study and were obtained in the Frankfort horizontal (FH) plane, under standardized conditions using vertically adjustable head holders.

All lateral cephalograms were traced by the first author to eliminate intra-examiner variability. The landmarks and planes used in this study and measured on each film are depicted in Fig. 3 . Twelve angular measurements and 12 linear measurements were made from each UCLP patient cephalogram using computer software WinCeph v. 9.0 (Rise Corporation, Sendai, Miyagi, Japan) ( Figs. 4 and 5 ). The permanent central incisors were not evaluated because the central incisors had not yet erupted in some children. In addition, patients with UCLP had a fissure in the posterior hard palate and they had no congenital posterior nasal spine; therefore, it was necessary to set a temporary PNS point. This was located at the intersection between a line traced from the maxillary tuberosity, which constitutes the anterior border of the pterygomaxillary fissure, and the nasal floor. Thus, the palatal plane was drawn as a line that linked anterior nasal spine (ANS) and the temporary point, and posterior nasal spine (PNS′) was defined as the intersection between the perpendicular line from the pterygomaxillary fissure (Ptm) and the palatal plane.

Fig. 3
Cephalometric skeletal landmarks and planes used in the analysis. The permanent central incisors were not evaluated because they had not erupted yet in some children. A, A-point; ANS, anterior nasal spine; Ar, articulare; B, B-point; Ba, basion; FH, Frankfort horizontal; Go, gonion; Me, menton; N, nasion; Or, orbitale; PNS, posterior nasal spine; PNS′, a temporary point of the PNS created by drawing a line perpendicular to the palatal plane from Ptm; Po, porion; Pog, pogonion; Ptm, pterygomaxillary fissure; S, sella.

Fig. 4
Cephalometric angular measurements: (1) BaSN; (2) SNA; (3) SNB; (4) ANB; (5) SNPog; (6) NAPog; (7) facial angle (FA); (8) gonial angle; (9) mandibular plane angle (MPA); (10) SN–MP; (11) PP–MP; (12) SN–PP. (MP, mandibular plane; PP, palatal plane.).

Fig. 5
Cephalometric linear measurements: (1) Ba–S; (2) S–N; (3) S–PNS′; (4) PNS′–A; (5) PNS′–ANS; (6) Pog–Go; (7) Cd–Go; (8) N–ANS; (9) N–PNS′; (10) ANS–Me; (11) S–Go; (12) N–Me. (Cd, condylion.).

Statistical analysis

Cephalometric measurements were compared between the groups using the Student t -test. The statistical analysis of the data was performed using the statistical package JMP Release 6.0 (SAS Institute, Cary, NC, USA). P -values of 0.05 or less were considered statistically significant.

To evaluate method errors, 14 randomly selected cephalograms were re-traced and re-measured by the first author with an interval of at least 3 months between tracings. The landmark localization error was assessed using the formula of Dahlberg. The error difference ranged from 0.05° to 0.15° for angular cephalometric measurements and from 0.06 mm to 0.15 mm for linear measurements. These errors were considered negligible.

Furthermore, multiple regression analysis was performed to assess the association between the independent variables, such as the timing of soft palate repair, timing of hard palate closure, preoperative cleft size, and cleft size at hard palate closure, and the dependent variable maxillary growth outcomes.

Facial diagram analysis

Facial diagrams were constructed using 11 landmarks collected from the lateral cephalograms and by measuring x y coordinates from a line perpendicular to the FH plane passing through the sella point (S) and from the FH plane. These measurements were compared with those of a non-cleft group.

Results

Patient outcomes

Lateral cephalograms were taken at 84.4 ± 6.4 (range 72–94) months in the F-group and at 86.3 ± 6.2 (range 73–95) months in the P-group; this difference was not statistically significant.

The average cleft size of the hard palate posterior edge before soft palate repair was 9.9 mm in the F-group and 10.5 mm in the P-group; this difference was not statistically significant. In addition, there were no significant differences in cleft size according to their distribution (right or left) between the two groups.

Cleft lips were repaired in both groups at an average age of 6 months, and there was no significant difference between the groups in the timing of this procedure. The soft palate was repaired at a mean age of 18 months in the F-group and 19 months in the P-group; this was not significantly different. The hard palate was closed at a mean age of 67 (range 62–74) months in the F-group and 72 (range 65–78) months in the P-group; this difference was significant ( P < 0.01) ( Table 2 ).

Table 2
Patient characteristics and surgical treatment.
F-group a P-group a P -value
Date of birth (year) 1994–2004 1983–1993
Subjects, n (male/female) 34 (19/15) 34 (24/10)
Age at evaluation, months, mean ± SD (range) 84.4 ± 6.4 (72–94) 86.3 ± 6.2 (73–95) NS
Age at cheiloplasty, months, mean ± SD (range) 5.8 ± 0.9 (4–7) 6.2 ± 1.3 (5–10) NS
Age at soft palate repair, months, mean ± SD (range) 18.2 ± 1.4 (17–22) 19.2 ± 2.7 (17–27) NS
Age at hard palate closure, months, mean ± SD (range) 67.1 ± 4.0 (62–74) 71.9 ± 4.9 (65–78) P < 0.01
SD, standard deviation; NS, no significant difference between groups.

a F-group: modified Furlow method; P-group: Widmaier–Perko method.

Lateral cephalometry

The cephalometric analysis of the two study groups (F-group and P-group) is presented in Table 3 . There was no significant difference in any angular or linear cephalometric measurement between the two groups.

Table 3
Angular and linear measurements: mean, standard deviation, and 95% confidence interval, with results of the t -test.
F-group a ( n = 34) P-group a ( n = 34) P -value 95% CI of the difference
Mean SD 95% CI Mean SD 95% CI
Angles (degrees) b
BaSN 132.44 4.91 130.95–133.94 131.99 3.41 130.80–133.18 NS −1.42–2.33
SNA 79.05 3.10 77.97–80.14 78.86 2.79 77.89–79.84 NS −1.24–1.62
SNB 75.31 3.56 74.07–76.56 74.99 3.19 73.88–76.11 NS −1.33–1.96
ANB 3.80 2.39 2.96–4.63 3.86 2.31 3.06–4.67 NS −1.21–1.07
SNPog 74.66 3.72 73.36–75.96 74.73 3.40 73.54–75.92 NS −1.80–1.66
NAPog 8.91 5.19 7.10–10.72 8.12 5.10 6.34–9.90 NS −1.70–3.29
FA 82.36 3.00 81.31–83.41 82.52 2.29 81.72–83.32 NS −1.45–1.14
Gonial angle 129.83 5.89 127.77–131.88 130.94 4.99 129.20–132.69 NS −3.77–1.53
MPA 32.80 4.95 31.07–34.53 32.22 4.15 30.77–33.67 NS −1.63–2.80
SN–MP 40.51 5.11 38.73–42.29 40.00 5.27 38.16–41.84 NS −2.01–3.03
PP–MP 30.07 4.59 28.44–31.61 29.55 5.17 27.75–31.35 NS −1.89–2.83
SN–PP 10.77 3.49 9.55–11.99 10.44 3.36 9.27–11.62 NS −1.34–1.99
Distances (mm) b
Ba–S 24.04 2.32 23.23–24.85 23.88 1.96 23.20–24.57 NS −0.89–1.20
S–N 63.82 2.96 62.79–64.86 62.47 2.79 61.50–63.45 NS −0.04–2.74
S–PNS′ 16.56 1.85 15.91–17.20 16.07 2.29 15.27–16.87 NS −0.52–1.50
PNS′–A 44.41 2.80 43.44–45.39 43.51 2.66 42.58–44.44 NS −0.41–2.23
PNS′–ANS 47.92 3.17 46.81–49.02 46.67 2.79 45.70–47.64 NS −0.20–2.70
Pog–Go 59.81 4.68 64.92–67.95 58.04 4.14 63.42–66.39 NS −0.55–3.62
Cd–Go 47.43 3.74 46.17–48.75 48.07 3.79 46.80–49.46 NS −2.49–1.15
N–ANS 47.53 3.18 46.43–48.64 47.03 3.44 45.83–48.23 NS −1.10–2.11
N–PNS′ 45.16 3.04 44.10–46.23 44.87 3.07 43.80–45.95 NS −1.19–1.78
ANS–Me 58.75 3.03 57.73–59.78 58.69 3.87 57.39–60.00 NS −1.62–1.75
S–Go 64.97 4.60 63.36–66.57 65.7 4.40 64.35–67.41 NS −3.10–1.27
N–Me 106.28 4.64 104.66–107.90 105.72 5.49 103.80–107.63 NS −1.90–3.03
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Dec 14, 2017 | Posted by in Oral and Maxillofacial Surgery | Comments Off on Cephalometric evaluation after two-stage palatoplasty combined with a Hotz plate: a comparative study between the modified Furlow and Widmaier–Perko methods
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