Unilateral cleft lip and palate Treatment outcome and long-term craniofacial growth
A scientific essay in Medical Sciences
DOCTORAL THESIS defended in public on 6th of November 2006
Chapter 1 introduces the topic of cleft lip and palate to the reader. Types of clefts, incidence and etiology are briefly discussed. Moreover, general aspects of the UCLP (UCLP = Unilateral Cleft Lip and Palate) malformation like its maxillofacial characteristics are described. The multidisciplinary treatment of patients with a UCLP in a cleft team as well as the effect of palatal surgery on further maxillofacial growth and development are discussed. The background of this thesis is elucidated by a description of the evaluation of treatment outcome in UCLP performed over the past years. An overview of the present thesis is presented.
Chapter 2 evaluates the dental arch relationships of a group of 43 patients with a complete UCLP from the Cleft Palate Craniofacial Unit of Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands. The dental arch relationships were evaluated at the age of 9 years with the help of the GOSLON Yardstick. All Nijmegen patients were treated with a 2-stage palatal closure: soft palate closure at 11 to 13 months of age, hard palate closure at 4 to 11 years of age. The Nijmegen GOSLON scores were compared with the GOSLON outcomes of the six individual centers (A-F) from the Eurocleft study, and possible relationships between treatment protocols and GOSLON outcomes were evaluated. For the Nijmegen UCLP group, it was found that 9% of dental arch relationships had a GOSLON score of 1, 52% had a score of 2, 30% has a score of 3, 9% had a score of 4, and none had a score of 5. The mean Nijmegen GOSLON score (2.36, SD 0.74) showed no significant differences with Eurocleft centers A, B and E, which achieved the best treatment results, but did significantly differ from GOSLON outcomes of Eurocleft centers D (p<0.001), C and F (p<0.01), which had relatively poor treatment outcome. Nijmegen and the best Eurocleft centers A, B and E had high volume operators but treatment protocols were not the same. The protocols of Nijmegen and center A with delayed hard palate closure differed substantially from the protocols of Eurocleft centers B and E where the anterior hard palate was closed at the age of 2 to 3 months. Treatment outcome of the Nijmegen patients with UCLP and treated with two-staged palatal closure including delayed closure of the hard palate was comparable to the results of the Eurocleft centers with the best outcome. Treatment protocol could not explain differences in the quality of treatment results.
The aim of the investigation described in chapter 3 was to assess determinants for treatment outcome in UCLP, rated according to the GOSLON Yardstick and “GOSLON-like” 5-year-index by means of a meta-analysis. Multiple databases were searched for publications in which patient groups were evaluated by GOSLON ranking or the “GOSLON-like” 5-year index. Based on the inclusion criteria, 15 publications were selected, and the following background variables could be extracted that were evaluated as determinants for treatment outcome in UCLP: year of birth, average age of the patient group, racial background, presence of Simonart’s band, use of infant orthopedics, palate closure before the age of 3 years versus palatal closure at a later age, alveolar bone grafting and number of surgeons. The total number of patients included in the meta-analysis was 1236. The only background variable with a significant (p=0.003) influence on the treatment outcome was the timing of palatal closure. Patients whose soft and hard palate were closed before the age of 3 years presented poorer GOSLON scores (mean score 2.9, SD 0.4) than patients whose hard palate closure was performed at a later age (mean GOSLON score 2.3, SD 0.2). Of all patients in the early palatal closure group, 29% were allocated a GOSLON score 4 or 5 versus only 4% of the patients treated with a delayed palatal closure procedure. So, when compared with delayed hard palate closure, 25% more patients required complex orthodontics or an ortho-surgical approach in case of early palatal closure. Well-designed, randomized clinical trials (RCTs) are required, however, for further investigation of the optimal timing for palatal closure.
Chapter 4 investigates the reliability of using photographs of study casts as an alternative to casts for rating dental arch relationships in UCLP. Records of 49 consecutive patients with a complete UCLP at the age of 9 years were used from the Cleft Palate Craniofacial Unit of the Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands. The dental casts as well as their corresponding photographs were scored independently by four observers, using the GOSLON Yardstick as rating system. A high intra- and inter-observer agreement was found for the GOSLON classification on dental casts as well as on their corresponding photographs. No significant differences were found between the GOSLON ratings of dental casts when compared with GOSLON ratings applied to the photographs of these dental cast. Thus, photographs of dental casts provide a consistent, reproducible method for rating dental arch relationships in patients with UCLP, and provide a reliable alternative to the application of the GOSLON Yardstick on dental casts. Testing of this new method showed that dental arch relationships in UCLP could be reliably rated on the Internet using photographs of dental casts, which will facilitate future evaluation and comparison of treatment outcome in cleft care.
Chapter 5 evaluates the nasolabial appearance of the Nijmegen patients with a complete UCLP, and compares this esthetic outcome with the esthetic results of the six individual centers from the Eurocleft study. This was done with the aim to select patients with the best treatment outcome for the international good practice archive, which is part of the EUROCRAN project. For the Nijmegen patients, relationships between ratings in nasolabial esthetics and dental arch relationships were also investigated. The nasolabial appearance of 42 consecutive Nijmegen patients with a complete UCLP was assessed by applying the Asher-McDade esthetic index at the age of 9 years. This index has also been used in the Eurocleft study, and consists of 4 different components (nasal deviation, nose form, vermilion border, nasal profile), which are scored separately on a 5-point-scale and subsequently averaged to an overall esthetic score (also on a 5-point scale with 1=very good nasolabial appearance to 5=very poor nasolabial appearance). The mean of the overall esthetic rating of the Nijmegen patients was 3.0 with a 90% central range from 2.0 to 3.7 on a scale from 1 to 5. With regard to the overall esthetic rating, Nijmegen showed similar treatment outcomes with Eurocleft centers A, D, E and F; Nijmegen scored significantly better than Eurocleft center C and significantly worse than Eurocleft center B (p≤0.05). Comparisons of treatment protocol could not explain differences in nasolabial appearance between Nijmegen and the Eurocleft centers. Within the Nijmegen patient group, no significant correlations between esthetic ratings and dental arch relationships could be established. The current comparative study is supportive in the selection of patient records that are suitable for the “good practice archive”, which is part of the EUROCRAN project.
Chapter 6 describes a long-term cephalometric study aimed to evaluate the craniofacial development of the Nijmegen patients with a complete UCLP and treated with 2-stage palate closure, including delayed closure of the hard palate. Prediction models for cephalometric outcome at age 18 were developed with cephalometric values at the ages 9 and 12 years. Moreover, the objective need for surgery at age 18 was predicted from cephalometric values at age 9 with the help of logistic regression analysis. Cephalograms of 43 consecutive patients with a complete UCLP from the Nijmegen Cleft Unit were analyzed at 9, 12 and 18 years. The patient group showed a retrusive craniofacial growth pattern for the maxilla and mandible, and a rather vertical growth pattern for the lower face. Using multiple linear regression, for most cephalometric variables, 40 to 80% of the cephalometric values at early adulthood could be explained by cephalometric values at the ages 9, 12, and gender or by the cephalometric values at age 9 only, and gender. Several cephalometric variables at age 9 (s-n-ss, s-n-pg, sss-ns-sms, sss-ns-pgs) were found significant predictors for the need for surgery at age 18. Moreover, the need for surgery at age 18 was correctly predicted from age 9 for 85% of the investigated patient group with the help of logistic regression analysis. Application of the current logistic regression analysis on another comparative cleft group would assess the true power of the prediction model.
In chapter 7, a general discussion is given on the problems encountered during this study as well as on the results found in the different parts of the thesis. The concept of 2-staged palate repair including delayed closure of the hard palate, which has been applied to the investigated Nijmegen patient group, is extensively discussed and related to literature. Concerns regarding speech and additional burdens of care might justify a 2-staged palate repair with an earlier closure of the hard palate than the age of 9 years, which is the current age at which hard palate closure is performed for the Nijmegen cleft group. However, prospective, well-designed controlled studies, especially on long-term results, are urgently needed to take an evidence-based decision on timing of hard palate repair.