Facial Profile Evaluation of Isolated Pierre Robin Sequence

Computerized Surgical Planning for Mandibular Distraction Osteogenesis

Mandibular distraction osteogenesis is a technically challenging procedure due to complex mandibular anatomy, especially in the treatment of Pierre-Robin Sequence due to variable bone thickness in the infant mandible and the presence of tooth buds. Computerized surgical planning (CSP) simplifies the procedure by preoperatively visualizing critical structures, producing cutting guides, and planning distractor placement. This paper describes the process of using CSP to plan mandibular distraction osteogenesis, including discussion of recent advances in the use of custom distractors.

Robin Sequence Facial Profile After Conservative Treatment: A Long-Term Follow-Up

INTRODUCTION

Robin sequence (RS) is a congenital clinical condition characterized by micrognathia, glossoptosis, and respiratory distress. Conservative methods could be responsible for releasing feeding and respiratory impairment but little information about mandibular growth is known in long-term follow-up.

OBJECTIVE

Assessing the longitudinal behavior of the facial profile of individuals with isolated RS who underwent conservative micrognathia treatment using photographs during the whole craniofacial growth.

METHODS

Photographs of the right facial profile of 100 patients were used (50 individuals with isolated RS and 50 individuals without craniofacial anomaly). The individuals with RS were evaluated at 3 different times (T1: infant, T2: mixed dentition, T3: permanent dentition) by measuring the facial convexity angle (FCA; G.Sn.Pog´). A comparison between T3 and control group (C), individuals without craniofacial anomalies and in permanent dentition, was also performed, checking the FCA, nasolabial angle (Ls.Sn.Cm), mentolabial fold (Li.Si.Pog´), facial inferior third (Sn.Gn´.C) angles and the ratio between middle anterior facial height and lower anterior facial height.

RESULTS

The T3 group showed an increased angle of facial convexity and increased facial inferior third angle and middle anterior facial height/lower anterior facial height ratio compared with the control group. In the longitudinal evaluation of individuals with isolated RS, significant differences were identified between T1 and T2 groups and T1 and T3 groups showing that the increased facial convexity was higher in the infants and that did not change significantly between the phases of mixed and permanent dentition.

CONCLUSIONS

RS showed increased facial convexity in all phases evaluated, but their convexity decreased with growth. When compared with individuals without craniofacial anomalies, the individuals continue to exhibit retrognathism in the permanent dentition. The lack of a mandible projection has led to a considerable number of orthognathic surgeries for the correction of discrepancies.

MicroNAPS: A Novel Classification for Infants with Micrognathia, Robin Sequence, and Tongue-based Airway Obstruction

Background

Robin sequence (RS) describes a heterogeneous population with micrognathia, glossoptosis, and upper airway obstruction (UAO). Workup, treatment, outcomes assessment, and research inclusion are widely variable. Despite several classifications and algorithms, none is broadly endorsed. The objective of this investigation was to develop and trial a novel classification system designed to enhance clinical communication, treatment planning, prognostication, and research.

Methods

This is a retrospective cross-sectional study. A classification system was developed with five elements: micrognathia, nutrition, airway, palate, syndrome/comorbidities (MicroNAPS). Definitions and a framework for "stage" assignment (R0-R4) were constructed. Stage "tongue-based airway obstruction" (TBAO) was defined for infants with glossoptosis and UAO without micrognathia. MicroNAPS was applied to 100 infants with at least 1-year follow-up. Clinical course, treatment, airway, and feeding characteristics were assessed. Descriptive and analytic statistics were calculated and a P value less than 0.05 was considered significant.

Results

Of the 100 infants, 53 were male. Mean follow-up was 5.0 ± 3.6 years. R1 demonstrated feeding-predominant mild RS for which UAO was managed nonoperatively but gastrostomy tubes were prevalent. R2 was characterized by airway-predominant moderate RS, typically managed with mandibular distraction or tongue-lip adhesion, with few gastrostomy tubes and short lengths-of-stay. R3 denoted severe RS, with similar UAO treatment to R2, but with more surgical feeding tubes and longer admissions. R4 represented a complex phenotype with 33% tracheostomies, protracted hospitalizations, and delayed palatoplasty. R0 ("at risk") and TBAO groups displayed the most variability.

Conclusions

MicroNAPS is easy to use and associated with relevant disease characteristics. We propose its adoption in clinical and research settings.

Prospective Evaluation of Children with Robin Sequence following Tübingen Palatal Plate Therapy

BACKGROUND

To assess the long-term functional orthodontic outcome of the Tübingen palatal plate (TPP) in children with Robin sequence (RS) in comparison to age- and sex-matched healthy controls.

METHODS

Between 09/2019 and 10/2020, we performed orthodontic assessments in 41 children at our Department of Orthodontics. Included were patients with RS (17 non-syndromic; four syndromic) and healthy controls (n = 22, average age in both groups 9.9 y). Facial analyses of 2D images, digital study casts and cephalometric measurements were made.

RESULTS

The orthodontic examinations showed no statistically significant group differences regarding functional extraoral, intraoral and pharyngeal parameters, or in skeletal patterns. The relationship between the upper and lower incisors was significantly increased (overjet 4 (2-10) vs. 3 (0-9) mm; p = 0.01) with a significant deficit in the lower face proportions (Jaw Index 4.15 (1.9-9.6) vs. 2.98 (0-9); p = 0.02; Facial convexity angle 157 (149-173) vs. 159 (149-170); p = 0.01).

CONCLUSION

Children with RS treated with the TPP showed normal long-term functional orthodontic outcomes, thanks to the functional adaption of the stomatognathic system. However, soft tissue growth did not completely match skeletal growth, resulting in a more convex facial profile.

Comparison Between Treacher Collins Syndrome and Pierre Robin Sequence: A Cephalometric Study

OBJECTIVE

The aim of this study was to compare the dentoskeletal pattern of Treacher Collins syndrome (TCS) and nonsyndromic Pierre Robin sequence (PRS).

DESIGN

Retrospective.

SETTING

Single center.

PATIENTS

Eighteen patients diagnosed with TCS (Group TCS) or PRS (Group PRS) in rehabilitation treatment at a single center. Group TCS was composed of 9 patients (4 male, 5 female) with a mean age of 12.9 years (standard deviation = 4.8). Group PRS was composed of 9 patients paired by age and sex with group TCS.

MAIN OUTCOME MEASURE(S)

Cone beam computed tomography-derived cephalometric images taken before the orthodontic or the orthodontic-surgical treatment were analyzed using Dolphin Imaging (Dolphin Imaging 11.0 & Management Solutions). Variables evaluating the cranial base, the maxillary and mandibular skeletal components, maxillomandibular relationship, the vertical components and the dentoalveolar region were measured. Intergroup comparisons were performed using t tests. The significance level considered was 5%.

RESULTS

Intergroup differences in the mandible size and growth pattern were observed. Group TCS showed a smaller mandibular length (Co-Go, Co-Gn) and a higher palatal plane (SN-Palatal Plane) and mandibular plane angles (SN-Go.Gn) compared to group PRS. No differences between TCS and PRS were observed for the sagittal position of the maxilla, maxillomandibular relationship, and dental components.

CONCLUSIONS

Treacher Collins syndrome presented a decreased mandible and a more severe vertical growth pattern compared to PRS.

The Reproducibility of the Jaw Index in the Measurement of Healthy Newborns

Objective:

Establish the reliability of the jaw index to objectify the relationship between the maxilla and mandible in healthy newborns.

Design:

Cohort study.

Setting:

Tertiary setting.

Patients:

A total of 52 healthy newborns were included to detect an inter and intraclass correlation coefficient (ICC) of 0.8 with a 95% confidence interval (95% CI) of width 0.3. Inclusion criteria were children born full term without respiratory or feeding problems, and without congenital malformations or facial deformities due to birth trauma. Uncooperative patients were excluded.

Interventions:

The jaw index, a measuring tool for objectifying micrognathia in children suspected of having Robin sequence, was used. An ICC of greater than 0.8 was considered clinically relevant.

Main Outcome Measure(s):

Primary outcomes are the reliability of the jaw index expressed as interclass correlation coefficient and ICC. Secondary outcomes are the mean jaw index and mean length of the mandible, maxilla, and the alveolar overjet.

Results:

An interclass correlation coefficient of 0.74 (95% CI: 0.49-0.86) and an ICC of 0.81 (95% CI: 0.66-0.89) were found. The mandible had an average length of 162.6 mm (standard deviation [SD] 11.1), the maxilla 168.7 mm (SD 9.4), the alveolar overjet 2.0 mm (SD 0.60), and the mean jaw index was 2.1 (SD 0.64).

Conclusion:

The jaw index is a consistent instrument between different observers as well as for one observer measuring consecutively in the same child, to objectify the size of the lower jaw compared to that of the upper jaw in healthy newborns.

Current Trends in Surgical Airway Management of Neonates with Robin Sequence

Background

Robin sequence is defined by the clinical triad of micrognathia, glossoptosis, and upper airway obstruction, and is frequently associated with cleft palate and failure to thrive. Though the efficacy of certain surgical interventions to relieve airway obstruction has been well established, algorithms dictating decision making and perioperative protocols are poorly defined.

Methods

A 22-question survey was sent via e-mail to members of the American Cleft Palate-Craniofacial Association and International Society of Craniofacial Surgeons. Questions were related to surgeon experience in treating neonates with Robin sequence, and specific perioperative protocols.

Results

One hundred fifty-one responses were collected. Most respondents were surgeons practicing in North America(82.8%), in a university hospital setting (81.5%) and had completed a fellowship in pediatric plastic surgery or craniofacial surgery (76.2%). Preoperative protocols varied widely by years in training and location of practice. Although 78.8% of respondents always performed direct laryngoscopy, only 49.7% of respondents routinely obtained preoperative polysomnography. Mandibular distraction osteogenesis was the most common primary surgical airway intervention reported by 74.2%, with only 12.6% primarily utilizing tongue-lip adhesion. Slightly less than half of respondents ever performed tongue-lip adhesion. Operative selection was influenced by surgeon experience, with 80% of those in practice 0-5 years primarily utilizing mandibular distraction, compared with 56% of respondents in practice >15 years.

Conclusions

This study documents wide variations in preoperative, operative, and postoperative protocols for the surgical airway management of neonates with severe Robin sequence. These results underscore the need to acquire more objective data, to compare different protocols and outcome measures.

Mandibular Catch-Up Growth in Pierre Robin Sequence: A Systematic Review

Objective:

The concept of mandibular catch-up growth is often quoted in the literature regarding Pierre Robin sequence (PRS). We endeavored to perform a systematic review of whether the literature supports this concept.

Design:

Systematic review.

Interventions:

A PubMed-based systematic review of the English literature was performed of articles objectively measuring mandibular growth or position after nonoperative management of PRS.

Main Outcome Measures:

Rate and end point of mandibular length, ramus length, gonial angle, and maxillomandibular discrepancy.

Results:

The initial search delivered 607 English-language abstracts. Of these, 16 met inclusion criteria. Eight articles evaluating 143 patients followed longitudinal patient data and therefore allowed comparison of growth rates to controls. Ten articles evaluating 228 patients presented cross-sectional data and therefore could only evaluate a single time point. Two of the 8 longitudinal studies reported faster than normal growth of mandibular length in a significant portion of their cohort. Five of 8 reported equal growth rates. One of 16 studies reported that mandibular length of patients with PRS normalized compared to controls. Two of 16 studies reported no difference in maxillomandibular discrepancy between PRS and controls, whereas 10 reported a posteriorly displaced mandible relative to the maxilla in PRS. Significant differences in control groups, patients, and age existed between studies.

Conclusions:

While the concept of catch-up growth in PRS is often quoted, a minority of objective studies suggest increased mandibular growth rates in isolated PRS. Even fewer studies suggest that the maxillomandibular discrepancy in PRS completely resolves.

Analysis of Arch Widths in Patients With Isolated Pierre Robin Sequence

Objective:

To compare arch widths of patients with isolated Robin sequence (IRS) operated using modified von Langenbeck technique and modified Furlow double-opposing z-plasty.

Design:

Retrospective, transversal study.

Setting:

Hospital of Rehabilitation of Craniofacial Anomalies, University of São Paulo, Bauru, Brazil.

Patients:

Three groups of patients were analyzed. Group VL comprised 30 patients with IRS operated by von Langenbeck technique (mean age of 8.1 years); group FL included 30 patients with IRS operated by Furlow technique (7.6 years); and the control group included 30 noncleft patients with class I occlusion (7.4 years). The palate repair was performed between 1.0 and 1.7 years of age in both study groups. Transversal measurements of maxillary and mandibular arches were performed digitally on 3D digital models.

Statistic:

The intergroup comparison was performed using analysis of variance and Tukey test. An independent t test was used to compare the complete and incomplete types of cleft in both study groups. The level of significance was 5%.

Results:

No statistically significant difference was found between the VL and FL groups for maxillary and mandibular arches. However, both groups showed decreased transversal dimensions compared with the control group ( P < .01) for both dental arches. No differences for arch widths were observed for complete or incomplete palatal clefts.

Conclusions:

No influence of palate repair techniques was observed in the transversal arch widths in patients with IRS. Children with IRS operated for palate repair showed constriction of the maxillary and mandibular dental arches compared with noncleft children regardless the palatal cleft extension.

Assessment of speech nasality in children with Robin Sequence

PURPOSE: To report the outcomes of primary palatoplasty in Robin Sequence (RS); to verify the relationship between modalities of assessment of nasality; to compare nasality between techniques at palatoplasty. METHODS: This study involved the identification of hypernasality in four modalities: live assessment with 4-point scale; live assessment with cul-de-sac test; multiple listeners' ratings of recorded phrase; nasometric assessment. Live ratings of speech nasality and nasalance scores were retrieved from charts, while a recorded phrase was rated by listeners for occurrence of hypernasality. Agreement between the modalities was established as well as association between nasality, nasal turbulence and age at surgery and at assessment. Fisher's exact test was used to compare findings between surgical techniques. RESULTS: Agreement between nasalance, live assessment with 4-point scale, live assessment with cul-de-sac, and multiple listeners' ratings of recorded samples ranged between reasonable (0.32) and perfect (1.00). Percentage occurrence of hypernasality varied largely between assessment modalities. Mean occurrence of hypernasality was lower for the group submitted to Furlow technique (26%) than the group that received von Langenbeck technique (53%). Only findings obtained live were statistically significant (scale: p=0.012; cul-de-sac: p<0.001). Listeners identified nasal turbulence for 22 (32%) samples out of the 69 recordings, and an association was found between hypernasality and nasal turbulence. CONCLUSION: Lower occurrence of hypernasality was identified for patients with RS in Furlow group. Identification of hypernasality varied largely among the four assessment modalities.