Effect of a Syndromic Diagnosis on Mandibular Size and Sagittal Position in Robin Sequence

Growth Patterns of the Maxillomandibular Complex in Preadolescent Patients With Pierre-Robin Sequence Using Cluster Analysis and Longitudinal Follow-Up Cephalometric Data

OBJECTIVE

To investigate the growth patterns of the maxillomandibular complex in preadolescent patients with Pierre-Robin sequence (PRS).

METHODS

The samples consisted of 20 preadolescent PRS patients who had cleft palate and did not undergo growth-modification therapy or surgical intervention [6 boys and 14 girls; mean age of lateral cephalograms taken, 8.8 y (T1) and 13.7 y (T2)]. According to k-means cluster analysis, four clusters were defined over 3 major groups at T1: (1) Both very retrusive maxilla and mandible group: Cluster-4 [n=4, very large gonial angle, very low facial height ratio (FHR)] and Cluster-1 (n=5, small gonial angle, normal FHR); (2) Retrusive maxilla and very retrusive mandible group (Cluster-3, n=7, normal gonial angle, very low FHR); and (3) Both normal maxilla and mandible group (Cluster-2, n=4, very large gonial angle, low FHR). Seven angular and ratio variables [sella-nasion-A point (SNA), sella-nasion-B point (SNB), A point-nasion-B point (ANB), saddle angle, gonial angle, mandibular-body-length/anterior-cranial-base-length (MBL/ACBL), and FHR] at T1 and T2 and growth change from T1 to T2 were investigated.

RESULTS

At T1, SNA, SNB, saddle angle, gonial angle (all P<0.05), and FHR (P<0.01) showed significant difference among 4 clusters. At T2, SNA, SNB and gonial angle (all P<0.05) still showed significant difference among 4 clusters. During T1 to T2, there was no significant change in variables at each cluster except an increase in MBL/ACBL in Cluster-1 and FHR in Cluster-3 (all P<0.05).

CONCLUSIONS

Preadolescent PRS patients exhibited diverse skeletal phenotypes at T1, which did not change significantly from their original skeletal patterns by growth during T1 to T2.

DLX6 and MSX1 from saliva samples as potential predictors of mandibular size: A cross-sectional study

INTRODUCTION

Morphologic features of the mandible are influenced by the genes of each individual. Mandible size is important to orthodontists because the mandible is the mechanism by which the lower face influences facial esthetics and dental function. To date, no biological marker has been identified that indicates eventual mandible size. This study aimed to correlate the expression of DLX5, DLX6, EDN1, HAND2, PRRX1, and MSX1 to mandible size.

METHODS

Fifty-nine orthodontic patients aged >6 years who had available cephalometric radiographs were studied. Patients were classified on the basis of condylion-to-gnathion measurements. Messenger RNA was isolated from saliva and subjected to real-time quantitative polymerase chain reaction.

RESULTS

Threshold cycle values for subjects with small mandibles (>1 standard deviation [SD] from the mean) had the least expression of DLX6 and MSX1. Threshold cycle values for subjects with large mandibles (>1 SD) had less expression of DLX6 and MSX1 than subjects within 1 SD but more than those with small mandibles.

CONCLUSIONS

DLX6 and MSX1 are related to mandible development and size. This finding could be used to improve treatment planning for medical and dental professionals seeking to understand the impact of genetics on bone growth.

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.

Congenital Mandibular Hypoplasia: Patient-Specific Total Joint Replacement as a Line Extension in the Treatment of Complex Craniofacial Anomalies

Introduction

Congenital mandibular hypoplasia (CMH) remains challenging because of the underlying combined hard and soft tissue deficiency. Treatment options include craniofacial distraction, orthognathic surgery, and autologous grafts, although the latter produces inadequate results after distraction and autologous grafting. Unsatisfactory long-term stability may cause relapse, necessitating reoperation.

Material and Methods

We investigated the feasibility of using alloplastic total joint replacement (TJR) in growing and young adult CMH patients. The primary outcome was long-term reconstruction stability, without implant failure. Secondary outcomes were TMJ function and pain, and jaw movements achieved during surgery.

Results

Three patients (age: 9–22 years) were treated by the same surgeon at one institution during 2018–2021. Anamnesis and clinical parameters were obtained from patient records. Preoperative 3D-scans were superimposed with postoperative 3D-scans and preoperative plans, including TJR-implant STL files, to measure jaw movement. All patients underwent prior reconstructive surgery. Mandibular movement of 16.4–20.1 mm in the sagittal direction was achieved. Post-TJR follow-up ranged from 24 to 42 months. No long-term complications occurred. At the latest follow-up, the maximal interincisal opening was between 21 and 40 mm, and all implants were functioning, without failure.

Conclusion

In selected CMH cases, alloplastic TJR can deliver satisfactory medium-term results with predictable and stable outcomes, even in growing patients.

Antibacterial properties of functionalized silk fibroin and sericin membranes for wound healing applications in oral and maxillofacial surgery

Oral wounds are among the most troublesome injuries which easily affect the patients' quality of life. To date, the development of functional antibacterial dressings for oral wound healing remains a challenge. In this regard, we investigated antibacterial silk protein-based membranes for the application as wound dressings in oral and maxillofacial surgery. The present study includes five variants of casted membranes, i.e., i) membranes-silver nanoparticles (CM-Ag), ii) membranes-gentamicin (CM-G), iii) membranes-control (without functionalization) (CM-C), iv) membranes-silk sericin control (CM-SSC), and v) membranes-silk fibroin/silk sericin (CM-SF/SS), and three variants of nonwovens, i.e., i) silver nanoparticles (NW-Ag), ii) gentamicin (NW-G), iii) control (without functionalization) (NW-C). The surface structure of the samples was visualized with scanning electron microscopy. In addition, antibacterial testing was accomplished using agar diffusion assay, colony forming unit (CFU) analysis, and qrt-PCR. Following antibacterial assays, biocompatibility was evaluated by cell proliferation assay (XTT), cytotoxicity assay (LDH), and live-dead assay on L929 mouse fibroblasts. Findings indicated significantly lower bacterial colony growth and DNA counts for CM-Ag with a reduction of bacterial counts by 3log levels (99.9% reduction) in CFU and qrt-PCR assay compared to untreated control membranes (CM-C and CM-SSC) and membranes functionalized with gentamicin (CM-G and NW-G) (p < 0.001). Similarly, NW-G yielded significantly lower DNA and colony growth counts compared to NW-Ag and NW-C (p < 0.001). In conclusion, CM-Ag represented 1log level better antibacterial activity compared to NW-G, whereas NW-G showed better cytocompatibility for L929 cells. As data suggest, these two membranes have the potential of application in the field of bacteria-free oral wound healing. However, provided that loading strategy and cytocompatibility are adjusted according to the antibacterial agents' characteristic and fabrication technique of the membranes.

Mandibular distraction to correct severe non-isolated mandibular hypoplasia: The role of drug-induced sleep endoscopy (DISE) in decision making

OBJECTIVES

In patients with mandibular hypoplasia, mandibular distraction osteogenesis (MDO) aims to relieve tongue-based airway obstruction. Drug-induced sleep endoscopy (DISE) provides a dynamic assessment of the upper airway and visualizes anatomical site and cause of airway obstruction. The aim of this study was to evaluate the effect of MDO on tongue-based airway obstruction found by DISE within a non-isolated patient population with severe upper airway obstruction (UAO). Furthermore, we aimed to assess the additional value of DISE in clinical decision making by correlating DISE findings to functional airway outcomes after MDO.

METHODS

Findings on DISE in children who underwent MDO were retrospectively gathered and evaluated. According to DISE findings, severity of tongue-based obstruction was scored using a 4-step classification similar to the one that is used by Bravo et al.. Intubation conditions were scored according to the Cormack Lehane score (CLS). Pre-and postoperative DISE findings were compared and correlated with functional airway outcomes following MDO.

RESULTS

In 19 out of 28 MDO procedures, both a pre-and postoperative DISE was available. Tongue-based obstruction scores improved in 13 procedures, which correlated to a functional improvement in seven. Postoperative tongue-based obstruction differed significantly between patients with successful MDO and patients treated unsuccessfully (2.00 ((Interquartile range (IQR) 1.00-2.00) vs. 3.00 (IQR 2.00-4.00), p = 0.028), whereas this difference was not significant for the CLS (1.00 (IQR 1.00-1.50) vs. 2.00 (IQR 1.00-4.00), p = 0.066). If no improvement of tongue-based obstruction was seen, MDO is very unlikely to be successful on the functional airway.

CONCLUSIONS

DISE provides information on the site and nature of airway obstruction and can visualize the effect of MDO on the severity of tongue-based airway obstruction. Therefore, it can be of additional value in understanding the differences in functional airway outcomes after MDO and aids in deciding appropriate and targeted treatment. Hence, standardized use of DISE, in addition to the clinical assessment of mandibular position and a polysomnography, during MDO management is highly recommended.

Characterization of phenotypes and predominant skeletodental patterns in pre-adolescent patients with Pierre-Robin sequence

Objective

To investigate the phenotypes and predominant skeletodental pattern in pre-adolescent patients with Pierre–Robin sequence (PRS).

Methods

The samples consisted of 26 Korean pre-adolescent PRS patients (11 boys and 15 girls; mean age at the investigation, 9.20 years) treated at the Department of Orthodontics, Seoul National University Dental Hospital between 1998 and 2019. Dental phenotypes, oral manifestation, cephalometric variables, and associated anomalies were investigated and statistically analyzed.

Results

Congenitally missing teeth (CMT) were found in 34.6% of the patients (n = 9/26, 20 teeth, 2.22 teeth per patient) with 55.5% (n = 5/9) exhibiting bilaterally symmetric missing pattern. The mandibular incisors were the most common CMT (n = 11/20). Predominant skeletodental patterns included Class II relationship (57.7%), posteriorly positioned maxilla (76.9%) and mandible (92.3%), hyper-divergent pattern (92.3%), high gonial angle (65.4%), small mandibular body length to anterior cranial base ratio (65.4%), linguoversion of the maxillary incisors (76.9%), and linguoversion of the mandibular incisors (80.8%). Incomplete cleft palate (CP) of hard palate with complete CP of soft palate (61.5%) was the most frequently observed, followed by complete CP of hard and soft palate (19.2%) and CP of soft palate (19.2%) (p < 0.05). However, CP severity did not show a significant correlation with any cephalometric variables except incisor mandibular plane angle (p < 0.05). Five craniofacial and 15 extra-craniofacial anomalies were observed (53.8% patients); this implicated the need of routine screening.

Conclusions

The results might provide primary data for individualized diagnosis and treatment planning for pre-adolescent PRS patients despite a single institution-based data.

Infant mandibular distraction in absence of ascending ramus: case series

BACKGROUND

Severe microretrognathia with the absence of ascending mandibular ramus is a challenging deformity and treatment must aim to avoid tracheostomy or remove it as soon as possible. Although it is not often reported, mandibular distraction osteogenesis represents a valid treatment option in infants affected by hypoplastic mandible Pruzansky-Kaban type IIb and III.

CASE PRESENTATION

The authors describe 3 cases of infants affected by severe respiratory insufficiency due to congenital mandibular hypoplasia, with follow up ranging from 4 to 8 years. Clinical and technical considerations on treatment choices and outcomes are discussed starting from review of the literature and direct clinical experience.

CONCLUSION

Early mandibular distraction, specifically bidirectional distraction, is an effective and repeatable technique that leads to mandible lengthening with counterclockwise rotation, pogonion projection increase, anteropositioning of the tongue base, and expansion of oropharyngeal volume with positive effect on the respiratory problems of the infant. Even in Treacher Collins patients, known to have a low decannulation rate, all of these elements are essential for effective speech and swallowing therapy and for a subsequent attempt of decannulation.

The Hypoplasic Mandible: What Makes it Different From the Healthy Child?

OBJECTIVE

This study aimed to analyze the morphology of the hypoplasic mandible and its evolution during the growth period to better understand how it differs from the pediatric healthy mandible.

METHOD

Three-dimensional mandibular models of hypoplasic and healthy children aged from 39 gestational weeks to 7 years old were analyzed with a morphometric method including data clustering. Morphological distinctions between pathological and healthy mandibles were highlighted. Bilateral and unilateral mandibular hypoplasia were distinguished.

RESULTS

The study sample was composed of 31 hypoplasic children and as many sex- and age-matched healthy children. Morphological distinctions between pathological and healthy mandibles were highlighted only from the first year of life. In bilateral hypoplasia, the overall mandibular dimensions were reduced while there was only a ramus asymmetry in unilateral mandibular hypoplasia (mean ± SD of the difference between the Grp03c and Grp03b subgroups: 6.80 ± 6.37 - P value = 1.64e^-3 for the height of the left ramus versus 0.18 ± 4.18 - P value = .82 for the height of the right ramus). Supervised classification trees were built to identify the pathology and discriminate unilateral from bilateral mandibular hypoplasia (prediction rates = 81% and 84%, respectively).

CONCLUSIONS

Based on a morphometric analysis, we demonstrated that mandibular hypoplasia significantly impacts the mandibular morphology only from the first year of life, with a distinction between bilateral and unilateral hypoplasia.

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.

A Novel Geometric Morphometric Analytical Method for Classifying Mandibular Morphology in Infants With Isolated Pierre Robin Sequence

PURPOSE

There is a lack of uniformity in the diagnostic criteria and system for the morphologic classification of micrognathia in infants with isolated Pierre Robin sequence (IPRS). Therefore, the aim of this study was to create a morphologic classification system for IPRS-affected mandibles that may guide surgical management and osteotomy design.

PATIENTS AND METHODS

We designed and implemented a retrospective cross-sectional study. The study sample included infants with IPRS. The predictor variables included shape variables of the IPRS-affected mandibles. The outcome of interest was morphologic differences among the IPRS-affected mandibles in the infancy stage. The original coordinate data of the mandibular images were analyzed by a generalized Procrustes analysis and 2-block partial least squares analysis to identify the focal and nonfocal areas in the IPRS-affected mandibles. The original feature points were modified according to the results of 2-block partial least squares analysis. The modified feature points were further analyzed by principal component analysis, K-means cluster analysis, and canonical variate analysis to obtain a morphologic classification of the IPRS-affected mandibles.

RESULTS

One hundred fifty infants with IPRS were enrolled in this study. Principal component analysis showed that the variations among IPRS-affected mandibles were mostly in terms of the shapes of the mandibular ramus, mandibular body, and angle of the mandible. On the basis of the results of K-means cluster analysis and canonical variate analysis, the mandibles in group A3 showed characteristics such as a simply shorter mandibular body. Group B3 was adjusted to show characteristics such as a shorter mandibular body with a more obtuse mandibular angle, whereas group C3 showed characteristics such as a shorter mandibular body with a shorter mandibular ramus.

CONCLUSIONS

Our study confirmed the hypothesis that there are quantifiable morphologic differences among the IPRS-affected mandibles, and it provided a morphologic classification of the IPRS-affected mandibles that will help to promote the clinical diagnosis and treatment.

Clinical outcomes of prenatal diagnosis of the fetal micrognathia: A case report

RATIONALE

Micrognathia is a subtle facial malformation characterized by a small mandible and receding chin. Fetal micrognathia is often associated with chromosomal abnormalities, skeletal dysplasia, and various syndromes. Once it is dignosised, detailed fetal malformation screening and chromosome examination should be carried out.

PATIENT CONCERN

One pregnant woman with suspicion of fetal micrognathia was referred from her local hospital to our hospital for detailed fetal malformation screening and fetal echocardiography. Examination of the fetus was performed using a two-dimensional and three-dimensional ultrasound probe in multiple planes. The fetus showed micrognathia without glossoptosis with features of the inferior facial angle (IFA) ≤50° and his tongue reached anterior mandibular border box during normal movement.

DIAGNOSES

The fetus was diagnosed as isolated micrognathia prenatally without multisystem abnormalities.

INTERVENTIONS

Amniocentesis was performed and the fetus was found to carry 46XN with 6q14.1 duplication, the significance of which was unclear.

OUTCOMES

The fetus was labored through vagina at 38 weeks gestation. A small soft cleft palate was diagnosed after delivery.

LESSONS

This case suggests that once prenatal diagnosis of the fetal micrognathia has been made, we should carefully examine the presence of fetus's multisystem developmental abnormalities and due consideration should be given for associated soft cleft palate.

Measuring the Position of the Mandibular Foramen in Relation to the Dentoalveolar Plane in Pierre Robin Patients: Establishing Safety of the Horizontal Osteotomy

BACKGROUND

Mandibular distraction with horizontal osteotomy of the ramus and vertical distraction vector has successfully treated airway obstruction in young Pierre Robin patients. Placing the osteotomy just above the dentoalveolar plane can minimize damage to the inferior alveolar nerve. This study maps the position of the mandibular foramen relative to the height of the dentoalveolar plane to demonstrate the safety of this technique in Pierre Robin neonates.

METHODS

Retrospective review of 3D CT scans of Pierre Robin patients was performed with inclusion criteria: ≤1 year of age, bilateral micrognathia requiring surgical intervention for airway (ie, tracheostomy versus mandibular distraction), no prior mandible surgery, and pre-operative 3D CT study. Demographic information collected included: age at CT scan, age at surgery, and genetic diagnosis. Using the 3D study of each patient's right mandible, a line at the level of the mandibular dentoalveolar plane was drawn across the lingual surface of the ramus and the distance to the mandibular foramen at a length perpendicular to the dentoalveolar plane line was then measured.

RESULTS

Fifteen patients were included in the study (at least 9 Pierre Robin). Average age at time of CT scan was 71.4 days old. The mandibular foramen was below the level of the dentoalveolar plane in all cases at an average distance of 4.7 mm. Average ramus height 46.2±13.4 CONCLUSIONS:: The dentoalveolar plane was consistently above the mandibular foramen in all patients. Thus, the horizontal corticotomy at a level just above the mandibular dentoalveolar plane spares the inferior alveolar nerve in neonatal Pierre Robin patients undergoing vertical vector mandibular distraction.

Mandibular growth in infants with Robin sequence treated with the Tübingen palatal plate

Background

Robin sequence (RS) is characterized by mandibular retrognathia, glossoptosis and upper airway obstruction. Whether mandibular catch-up growth may occur in RS is yet controversial. Our functional and less invasive treatment including the Tübingen Palatal Plate (TPP), early oral feeding and orofacial stimulation may promote mandibular catch-up growth. We evaluated the effect of the Tübingen Palatal Plate on mandibular growth, expressed by the Jaw index, sleep study results and weight gain in infants admitted with isolated and syndromic RS, born at or referred to our center between 6/2015 and 5/2018.

Methods

Retrospective analysis of our electronic patient database that included data on jaw index measurements, sleep study results and standard deviation (Z-)scores for weight.

Results

Of 31 patients referred for RS treatment (22 isolated, 9 syndromic), we had data on the above parameters, determined at admission, discharge and 3 months after discharge, in 20. Jaw index at admission and 3-month follow-up was 8.8 (6.3–11.3) and 2.1 (2.0–4.0), respectively (median (IQR); p < 0.0001). Mixed-obstructive apnea index (MOAI) decreased from 9.7 (4.8–24.2) to 0.0 (0–1.3; p < 0.002). No significant correlation was observed between MOAI and Jaw Index, but MOAI correlated with the Maxillary/Mandibular arch ratio (r = 0.58; p < 0.001).

Z-scores for weight were similar at both time points at − 1.34 (− 1.76 – − 0.57) and − 1.50 (− 1.89 – − 0.54), while the proportion of infants requiring nasogastric tube feeding decreased from 84 to 8%. No infant had craniofacial surgery; one with syndromic RS required tracheostomy.

Conclusion

These longitudinal cohort data suggest that the Tübingen Palatal Plate as used here may alleviate upper airway obstruction by promoting mandibular growth.

Trial registration

N.A.

Surgical Management and Outcomes of Pierre Robin Sequence: A Comparison of Mandibular Distraction Osteogenesis and Tongue-Lip Adhesion

There is a paucity of literature directly comparing tongue-lip adhesion versus mandibular distraction osteogenesis in surgical treatment of patients with Pierre Robin sequence. This study comprehensively reviews the literature for evaluating airway and feeding outcomes following mandibular distraction osteogenesis and tongue-lip adhesion. A search was performed using the MEDLINE and Embase databases for publications between 1960 and June of 2017. English-language, original studies subjects were included. Extracted data included prevention of tracheostomy (primary airway outcome) and ability to feed exclusively by mouth (primary feeding outcome). A total of 67 studies were included. Ninety-five percent of subjects (657 of 693) treated with mandibular distraction osteogenesis avoided tracheostomy, compared to 89% of subjects (289 of 323) treated with tongue-lip adhesion. Eighty-seven percent of subjects (323 of 370) treated with mandibular distraction osteogenesis achieved full oral feeds at latest follow-up. Seventy percent of subjects (110 of 157) treated with tongue-lip adhesion achieved full oral feeds at latest follow-up. The incidence of second intervention for recurrent obstruction ranged from 4 to 6 percent in mandibular distraction osteogenesis studies, compared to a range of 22 to 45 percent in tongue-lip adhesion studies. Variability of patient selection, surgical techniques, outcomes measurement methods, and follow-up length across studies precluded meta-analysis of the data. Both mandibular distraction osteogenesis and tongue-lip adhesion are effective alternatives to tracheostomy for patients who fail conservative management and improve feeding. Mandibular distraction osteogenesis may be superior to tongue-lip adhesion in long-term resolution of airway obstruction and avoidance of gastrostomy, but is associated with notable complications.

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.

Cleft Palates and Occlusal Outcomes in Pierre Robin Sequence

Objective

To assess the dental class occlusion and lateral cephalometry of children with conservatively treated Pierre Robin sequence (PRS) and to identify associations between these findings and prepalatoplasty cleft palate measurements.

Study Design

Retrospective cohort study.

Subjects and Methods

Among 22 patients with PRS, the following data were prospectively collected: demographics and preoperative cleft palate measurements. After patients reached age 6 years, an orthodontist assessed dental occlusion class and performed a lateral cephalometric analysis. PRS cephalometric data were compared with reference population values. Bivariate logistic regression was used to test the association with malocclusion class. Results are presented as odds ratios with 95% profile likelihood confidence intervals. The association between cleft measurements and cephalometric parameters was tested with Spearman’s correlation ( rs).

Results

All 22 patients had bimaxillary hypoplasia and were prone to hyperdivergency, with a 41% rate of dental class III malocclusion. An increased anterior growth of the still retrusive mandible mostly accounts for the occurrence of the class III malocclusion in PRS (class II SNB = 74.3° vs class III SNB = 77.6°, P = .04). A larger cleft at the time of the cleft repair (mean, 11 months) was associated with increased mandibular retrusion (smaller SNB angle, rs = −0.5, P = .02).

Conclusions

The 41% rate of class III malocclusion among these conservatively treated patients needs to be considered in the choice of the initial airway approach. The future impact of early mandibular advancement will have to be determined.

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.

The ontogeny of Robin sequence

The triad of micrognathia, glossoptosis, and concomitant airway obstruction defined as "Robin sequence" (RS) is caused by oropharyngeal developmental events constrained by a reduced stomadeal space. This sequence of abnormal embryonic development also results in an anatomical configuration that might predispose the fetus to a cleft palate. RS is heterogeneous and many different etiologies have been described including syndromic, RS-plus, and isolated forms. For an optimal diagnosis, subsequent treatment and prognosis, a thorough understanding of the embryology and pathogenesis is necessary. This manuscript provides an update about our current understanding of the development of the mandible, tongue, and palate and possible mechanisms involved in the development of RS. Additionally, we provide the reader with an up-to-date summary of the different etiologies of this phenotype and link this to the embryologic, developmental, and genetic mechanisms.

Severity of Retrognathia and Glossoptosis Does Not Predict Respiratory and Feeding Disorders in Pierre Robin Sequence

Pierre Robin sequence (PRS) may lead to life-threatening respiratory and feeding disorders. With the aim to analyse the association of the severities of retrognathia and glossoptosis with those of respiratory and feeding disorders, we retrospectively studied a series of 50 infants with retrognathia, glossoptosis, cleft palate, and airway obstruction. The patients were managed from birth to at least 6 years of age by a single pediatric team at the Armand Trousseau Hospital in Paris within a 12 years period (2000-2012). Retrognathia and glossoptosis were graded in the neonatal period according to a specific clinical examination. Ventilation assistance was required for 32/50 (64%) patients, and enteral feeding for 41/50 (82%). The grades of retrognathia and glossoptosis and the severity of respiratory disorders did not differ between patients with isolated PRS and syndromic PRS. Severe respiratory disorders were more common and long-lasting feeding (>12 months) was more frequently required in patients with syndromic PRS compared with isolated PRS (42 vs. 13%, p = 0.04 and 42 vs. 4%, p < 0.01 respectively). Using univariate analysis, neurological impairments and laryngomalacia were associated with severe respiratory disorders [Odds ratio (OR) 5.0, 95% CI 1.3-19.6; and OR 14.6, 95% CI 1.3-161.4; p < 0.05] as well as with long-lasting feeding (>12 months) disorders (OR 18.6, 95% CI 3.9-89.2 and OR 20.4, 95% CI 3,4-122.8; p < 10^-2). Syndromic SPR status was also associated with severe respiratory disorders (OR 4.9, 95% CI 1-32.5; p < 0.05). Using multivariate analysis, only syndromic PRS status was predictive for severe respiratory disorders (adjusted OR 8, 95% CI 1.47-44.57; p < 0.05); and only neurological impairments remained a significant risk for long lasting feeding disorders (>12 months) (adjusted OR 21.72, 95% CI 3.4-138.63; p < 10^-2). The grades of retrognathia and glossoptosis were not predictive factors for the severity of respiratory and feeding disorders. Conclusion: In children with PRS, the severity of clinical conditions may not correlate with anatomic variables but rather with laryngeal abnormalities, neurological impairement and syndromic PRS status.

Update on 13 Syndromes Affecting Craniofacial and Dental Structures

Care of individuals with syndromes affecting craniofacial and dental structures are mostly treated by an interdisciplinary team from early childhood on. In addition to medical and dental specialists that have a vivid interest in these syndromes and for whom these syndromes are of evident interest, experts of scientific background-like molecular and developmental geneticists, but also computational biologists and bioinformaticians-, become more frequently involved in the refined diagnostic and etiological processes of these patients. Early diagnosis is often crucial for the effective treatment of functional and developmental aspects. However, not all syndromes can be clinically identified early, especially in cases of absence of known family history. Moreover, the treatment of these patients is often complicated because of insufficient medical knowledge, and because of the dental and craniofacial developmental variations. The role of the team is crucial for the prevention, proper function, and craniofacial development which is often combined with orthognathic surgery. Although the existing literature does not provide considerable insight into this topic, this descriptive review aims to provide tools for the interdisciplinary team by giving an update on the genetics and general features, and the oral and craniofacial manifestations for early diagnosis. Clinical phenotyping together with genetic data and pathway information will ultimately pave the way for preventive strategies and therapeutic options in the future. This will improve the prognosis for better functional and aesthetic outcome for these patients and lead to a better quality of life, not only for the patients themselves but also for their families. The aim of this review is to promote interdisciplinary interaction and mutual understanding among all specialists involved in the diagnosis and therapeutic guidance of patients with these syndromal conditions in order to provide optimal personalized care in an integrated approach.

Upper Airway Computed Tomography Measures and Receipt of Tracheotomy in Infants With Robin Sequence

IMPORTANCE

Airway management in infants with Robin sequence is challenging. Objective upper airway measures associated with severe airway compromise requiring tracheotomy are needed to guide decision making.

OBJECTIVES

To define objective upper airway measures in infants with Robin sequence from craniofacial computed tomography (CT) and to identify those measures in Robin sequence associated with tracheotomy.

DESIGN, SETTING, AND PARTICIPANTS

A cohort study (2003 to 2014, over 1-year follow-up) of 37 infants with Robin sequence evaluated for surgical management and 37 selected age- and sex-matched controls without a craniofacial condition conducted in a pediatric institution's craniofacial center.

MAIN OUTCOMES AND MEASURES

Define and compare CT-generated upper airway measures in these groups: infants with Robin sequence vs controls, and infants with Robin sequence with vs without tracheotomy. A negative difference signifies lower values for the Robin sequence and tracheotomy groups. Clinical data collected included age and height at time of CT scan, sex, tracheotomy presence, associated syndrome, and laboratory indicators of hypoventilation and hypoxemia. To evaluate interrater reliability, 2 raters performed each measurement in the Robin sequence group.

RESULTS

In 74 infants, 17 of 28 measures were different between infants with Robin sequence and those in the control group. Tracheotomy was performed in 14 of 37 (38%) infants with Robin sequence. Infants with tracheotomy more commonly had associated syndromes (12 of 14 [86%] vs 11 of 23 [48%]) and a history of hypoventilation and hypoxemia (13 of 14 [93%] vs 15 of 23 [65%]). Five of the 11 measures associated with tracheotomy were reliable and simpler to measure with the following mean differences (95% CIs) between groups: tongue length, 0.87 (0.26 to 1.48); tongue position relative to palate, 0.83 (0.22 to 1.45); mandibular total length, -0.8 (-1.42 to -0.19); gonial angle, 0.71 (0.08 to 1.34); and inferior pogonial angle, 0.66 (0.02 to 1.29). Using a receiver operating characteristic analysis, a composite score of these 5 measures for predicting tracheotomy risk yielded an area under the curve of 0.83 and achieved 86% sensitivity and 74% specificity.

CONCLUSIONS AND RELEVANCE

Computed tomography measures quantifying tongue position and mandibular configuration can identify infants with Robin sequence, and importantly, differentiate those who have severe upper airway compromise requiring tracheotomy. Following validation, these measures can be used for objective upper airway assessment and for expediting clinical decision-making in these challenging cases for which no such tools currently exist.

Pierre Robin Sequence: A Familial, Clinical, and Pathoanatomical Record of an Affected Dachshund

This study describes a spontaneous case of Pierre Robin sequence in a nonhuman animal species. A miniature dachshund with micrognathia developed glossoptosis, respiratory distress, dysphagia, temporomandibular ankylosis, and a misaligned upper jaw. The severity of this condition resulted in death by obstructive apnea at the age of 8 mo. Dogs with Pierre Robin sequence can provide further knowledge and a greater understanding of this abnormality, leading to better management of affected individuals and improvement of therapeutic methods.

Pierre Robin sequence: review of diagnostic and treatment challenges

Pierre Robin sequence is not a rare condition and paediatric specialists caring for respiratory related issues are likely to encounter cases in their practice. There have been a few recent reviews on the topic, mostly focusing on the surgical interventions performed for cases with severe airway obstruction. In the present review, we will highlight the different challenges that remain today in the global evaluation of infants afflicted with this condition through a thorough review of the medical literature, giving the clinician a full scope of the disease and of the various management options. The need for an improved objective evaluation of airway obstruction and for a better classification will be emphasized. We are therefore proposing a novel classification scheme that will better account for respiratory and feeding difficulties in these infants. Finally, many knowledge gaps persist regarding this condition, underlining the necessity for further research both in the genetic field and regarding the outcome of therapy.

A pragmatic approach to infants with Robin sequence: a retrospective cohort study and presence of a treatment algorithm

Objectives

Initial approaches to and treatments of infants with Robin sequence (RS) is diverse and inconsistent. The care of these sometimes critically ill infants involves many different medical specialties, which can make the decision process complex and difficult. To optimize the care of infants with RS, we present our institution’s approach and a review of the current literature.

Material and methods

A retrospective cohort study was conducted among 75 infants diagnosed with RS and managed at our institution in the 1996–2012 period. Additionally, the conducted treatment regimen in this paper was discussed with recent literature describing the approach of infants with RS.

Results

Forty-four infants (59 %) were found to have been treated conservatively. A significant larger proportion of nonisolated RS infants than isolated RS infants needed surgical intervention (53 vs. 25 %, p = .014). A mandibular distraction was conducted in 24 % (n = 18) of cases, a tracheotomy in 9 % (n = 7), and a tongue–lip adhesion in 8 % (n = 6). Seventy-seven percent of all infants had received temporary nasogastric tube feeding. The literature review of 31 studies showed that initial examinations and the indications to perform a surgical intervention varied and were often not clearly described.

Conclusions

RS is a heterogenic group with a wide spectrum of associated anomalies. As a result, the decisional process is challenging, and a multidisciplinary approach to treatment is desirable. Current treatment options in literature vary, and a more uniform approach is recommended.

Clinical Relevance

We provide a comprehensive and pragmatic approach to the analysis and treatment of infants with RS, which could serve as useful guidance in other clinics.

Airway Management in Pierre Robin Sequence: Patterns of Practice

Objectives

To report survey results from American Cleft Palate–Craniofacial Association members on the practice patterns of airway obstruction management in patients with Pierre Robin sequence.

Design

A 10-question online survey was sent and the data were reviewed.

Setting

Online survey of members of the American Cleft Palate–Craniofacial Association.

Patients

Surveys assessed management patterns of patients with Pierre Robin sequence whom a surgeon member of the American Cleft Palate–Craniofacial Association treated for airway obstruction.

Interventions

The survey comprised data on management strategies for airway obstruction in Pierre Robin sequence, including tracheostomy, tongue-lip adhesion, mandibular distraction, and treatments that falls in the “other” category.

Results

A total of 87 American Cleft Palate–Craniofacial Association members completed the survey. Respondents' results were analyzed as a whole and by individual subspecialty: plastic surgery (n = 33), oromaxillofacial surgery (n = 21), and otolaryngology (n = 29). Although most of the surgeons were trained to manage airway obstruction in Pierre Robin sequence patients using tracheostomy (47%, n = 39) and tongue-lip adhesion (31%, n = 26), 48% reported a current preference for mandibular distraction (n = 40). Of surgeons who preferred to manage Pierre Robin sequence with tongue-lip adhesion (n = 23), 65% were trained to do so (n = 15). Surgeons preferring mandibular distraction (n = 40) and tracheostomy (n = 14) more often reported they were trained to manage Pierre Robin sequence with tracheostomy.

Conclusions

Currently there are various practice patterns for the management of airway obstruction in Pierre Robin sequence. Training habits and subspecialty category may influence a surgeon's preference in patients who fail conservative therapy. Treatment guidelines are lacking and may require significant collaboration among centers and subspecialties to develop a more standardized approach to a challenging clinical entity.

Pierre Robin sequence and Treacher Collins hypoplastic mandible comparison using three-dimensional morphometric analysis

Pierre Robin sequence and Treacher Collins syndrome are both associated with mandibular hypoplasia. It has been hypothesized, however, that the mandible may be differentially affected. The purpose of this study was to therefore compare mandibular morphology in children with Pierre Robin sequence with children with Treacher Collins syndrome using three-dimensional analysis of computed tomographic scans. A retrospective analysis was performed identifying children with Pierre Robin sequence and Treacher Collins syndrome undergoing computed tomography. Three-dimensional reconstruction was performed, and ramus height, mandibular body length, and gonial angle were measured. These were then compared with those in control children with normal mandibles and with the clinical norms corrected for age and sex based on previously published measurements. Mandibular body length was found to be significantly shorter for children with Pierre Robin sequence, whereas ramus height was significantly shorter for children with Treacher Collins syndrome. This resulted in distinctly different ramus height-mandibular body length ratios. In addition, the gonial angle was more obtuse in both the Pierre Robin sequence and Treacher Collins syndrome groups compared with the controls. Three-dimensional mandibular morphometric analysis in patients with Pierre Robin sequence and Treacher Collins syndrome thus revealed distinctly different patterns of mandibular hypoplasia relative to normal controls. These findings underscore distinct considerations that must be made in surgical planning for reconstruction.

Underlying genetic diagnosis of Pierre Robin sequence: retrospective chart review at two children's hospitals and a systematic literature review

OBJECTIVES

To determine the underlying genetic diagnosis of Pierre Robin sequence (PRS) in 2 cohorts of individuals, assess the accuracy of genetic evaluation in young infants with PRS, and contrast the interventions provided to children with isolated and syndromic PRS.

STUDY DESIGN

The study involved retrospective chart reviews at 2 children's hospitals and a systematic literature review.

RESULTS

Approximately 40% of the patients had isolated PRS, and 60% of the patients had additional syndromic features. The patients with PRS with syndromic features required more aggressive medical management. Stickler syndrome was the most common syndromic diagnosis in PRS. The difficulty of making an accurate genetic diagnosis during the neonatal period was demonstrated.

CONCLUSION

All infants with PRS should be evaluated to check for the presence of syndromic features, and a longitudinal follow-up is warranted to monitor for the development of any syndromic features.

Neonates with Tongue-Based Airway Obstruction

Objective. In this systematic review, the authors summarize the current evidence in the literature regarding diagnosis, treatment, and long-term outcomes in neonates with tongue-based airway obstruction (TBAO) and assess the level of evidence of included studies.

Data Sources. The terms Pierre Robin syndrome/sequence, micrognathia, retrognathia, and cleft palate were combined with airway obstruction, treatment, tongue-lip plication, and osteogenesis distraction to perform an Ovid literature search, yielding 341 references. The authors excluded references containing patients with isolated choanal/nasal obstruction, patients older than 12 months, and expert opinion papers, yielding 126 articles.

Review Methods. The authors searched 3 electronic databases and reference lists of existing reviews from 1980 to October 2010 for articles pertaining to the diagnosis, treatment, and outcomes of TBAO. Reviewers assigned a level of evidence score based on Oxford’s Centre for Evidence Based Medicine scoring system and recorded relevant information.

Results. Most studies were case studies and single-center findings. The lack of standardization of diagnostic and treatment protocols and the heterogeneity of cohorts both within and between studies precluded a meta-analysis. There was little evidence beyond expert opinion and single-center evaluation regarding diagnosis, treatment, and long-term outcomes of neonates with TBAO.

Conclusions. The variability in the phenotype of the cohorts studied and the absence of standardized indications for intervention preclude deriving any definitive conclusions regarding diagnostic tools to evaluate this patient population, treatment choices, or long-term outcomes. A coordinated multicenter study with a standardized diagnostic and treatment algorithm is recommended to develop evidence for the diagnosis and treatment of neonates with TBAO.

Facial skeletal morphology in growing children with Pierre Robin sequence

OBJECTIVE

The purpose was to compare the jaw size, jaw relationship, and facial proportions of children with nonsyndromic Pierre Robin sequence with children with nonsyndromic or isolated cleft palate.

DESIGN

This is a retrospective cohort study comparing radiographic findings in children with Pierre Robin sequence or isolated cleft palate at two time intervals: ages 4 to 7 years (T1) and ages 10 to 13 years (T2). Linear and angular measurements were obtained using cephalograms; the cephalometric values were compared with unpaired t tests, assuming unequal variances.

SETTING

The study was conducted at the Center for Craniofacial Anomalies at the University of California, San Francisco.

PATIENTS

The sample included 13 children with Pierre Robin sequence and 14 children with isolated cleft palate who were followed at University of California, San Francisco, craniofacial anomalies clinic during the period from 1971 to 2007 and met the inclusion criteria.

MAIN OUTCOME MEASURES

The outcome measures were mandibular length, maxillary length, and sagittal jaw relationship in Pierre Robin sequence and isolated cleft palate children at T1 and T2.

RESULTS

During early childhood (T1: 4 to 7 years), mandibular length (Co-Gn) was similar in both Pierre Robin sequence and isolated cleft palate groups, as was the maxillary length (Co-A). In older children (T2: 10 to 13 years) mandibular length was significantly shorter in the Pierre Robin sequence group compared with the isolated cleft palate group (difference  =  10.9 mm, p  =  .009). Maxillary length in Pierre Robin sequence and isolated cleft palate groups was similar at T2 but significantly shorter in comparison to age-matched norms with a difference of 14.5 mm (p  =  .037) for Pierre Robin sequence and 12.4 mm (p  =  .045) for isolated cleft palate. Children with Pierre Robin sequence did not show a sagittal jaw discrepancy due to a proportionate deficiency in maxillary and mandibular length; whereas, children with isolated cleft palate showed a greater sagittal jaw discrepancy due to normal mandibular length and deficiency in maxillary length.

CONCLUSION

Our study confirms the findings of some previous studies that suggest that children with nonsyndromic Pierre Robin sequence have a proportionate retrusion of the maxilla and mandible, resulting in a convex facial profile by early adolescence.