Hyoid bone morphology in patients with isolated robin sequence - A case-control study utilizing 3D morphable models.

Background: Abnormalities of the hyoid bone are associated with impairment of oropharyngeal functions including feeding, swallowing, and breathing. Few studies have characterized anatomic abnormalities of the hyoid in patients with Robin sequence (RS), e.g. a less mineralized and voluminous hyoid. The purpose of this study was to compare normal hyoid bone morphology and hyoid bone morphology in children with isolated RS. Methods: Three-dimensional (3D) reconstructions of the hyoid bone were obtained from CT-imaging of children with RS and unaffected controls. A 3D morphable model was constructed using Principal Component Analysis (PCA). Partial least squares - Discriminant Analysis (PLS-DA) and multivariate analysis of variance (MANOVA) were used to characterize and compare hyoid shape differences between patients with RS and an age-matched control group. Results: The study included 23 subjects with RS (mean age 9.8 ± 10.3 months) and 46 age-matched control samples. A less voluminous hyoid was observed for the RS group with a larger lateral divergence of the greater horns compared to controls (MANOVA, p-value<0.001). The first shape variable from the PLS-DA model showed a significant correlation for the observed variance between the two groups (Spearman R = -0.56, p-value<0.001). The control samples and 151 CT-scans of subjects up to age 4 years were used to create a 3D morphable model of normal hyoid shape variation (n = 197, mean age 22.1 ± 13.1 months). For the normal 3D morphable model, a high degree of allometric shape variation was observed along the first principal component. Conclusions: The 3D morphable models provide a comprehensive and quantitative description of variation in normal hyoid bone morphology, and allow detection of distinct differences between patients with isolated RS and controls.

Incidence of occult cleft palate on prenatal magnetic resonance images obtained for non-cleft indications.

Prenatal diagnosis of craniofacial anomalies has improved family education and preparedness. Isolated cleft palate, however, remains difficult to identify sonographically. The aim of this study was to investigate the rate of incidental cleft palate identified on fetal magnetic resonance imaging (MRI) following the ultrasound detection of non-cleft abnormalities. This was a retrospective study of pregnant women who had fetal MRI performed between 2003 and 2017. To be included, the woman had to have been referred for fetal imaging for a non-cleft indication, with subsequent identification of an isolated cleft palate on MRI. Fetuses with a postnatal diagnosis of Robin sequence were excluded. The study sample included 30 women. Mean gestational age at MRI was 24 weeks 4 days± 38 days. Most referrals (76.7%) were for non-cleft craniofacial anomalies, of which micrognathia was the most common (63.3%). The annual incidence of occult cleft palate diagnosis was 0.4%, and a genetic syndrome was suspected based on imaging findings in 76.7%. Although rare, isolated cleft palate found incidentally on fetal imaging led to concern for a genetic syndrome in a high percentage of cases. This suggests that early referral for fetal MRI may provide critical information when sonographic fetal anomalies have been identified.

Increased risk of temporomandibular joint disorders and craniofacial deformities in patients with juvenile idiopathic arthritis: a population-based cohort study.

Juvenile idiopathic arthritis (JIA) is an autoimmune disease that has been proposed to involve the temporomandibular joint (TMJ). The aim of this study was to identify the relationships between JIA, TMJ disorders, and craniofacial deformities. This cohort study included patients diagnosed with clinically active JIA between 1999 and 2013 through a nationwide longitudinal health registry. The primary outcome was the presence of a TMJ disorder. The secondary outcome was the presence of a JIA-associated craniofacial deformity. A total of 2791 patients with JIA were included in the case group; 11,164 propensity score-matched individuals without JIA were selected from the same database as controls. TMJ disorders were present in 142 individuals: 48 (1.72%) in the case group and 94 (0.84%) in the control group (relative risk 2.047, 95% confidence interval 1.446-2.898). Craniofacial deformities were present in 374 individuals: 112 (4.01%) in the case group and 262 (2.35%) in the control group (relative risk 1.722, 95% confidence interval 1.380-2.148). Patients with JIA showed a significantly greater likelihood of developing TMJ disorders and craniofacial deformities compared to matched controls.

Early weight gain in infants with Robin sequence after mandibular distraction.

This retrospective cohort study was performed to assess weight gain in infants with Robin sequence (RS) treated by mandibular distraction osteogenesis (MDO). The primary outcome variable was average daily weight gain for the following time periods: (1) birth to MDO (T1), (2) MDO to distractor removal (T2), (3) distractor removal to 6 months later (T3), and (4) 6 months to 12 months following distractor removal (T4). Published growth curves were used for comparison. Differences were assessed using the Wilcoxon matched-pairs signed rank test. Twenty-two infants were included in the study. During T1, the infants had 9.47 ± 12.61 g/day less weight gain than expected (P = 0.001). However, for T2, T3, and T4, the infants demonstrated 3.48 ± 6.17 g/day (P = 0.028), 2.19 ± 4.47 g/day (P = 0.030), and 1.83 ± 3.25 g/day (P = 0.028) more weight gain than expected. Feeding tube use resulted in improved weight gain during T1 (P < 0.001), but was associated with poorer weight gain in T3 (P = 0.003) and T4 (P = 0.001). In conclusion, infants with RS treated by MDO demonstrated poorer weight gain relative to their peers between birth and the MDO operation. However, from the MDO procedure to 12 months post-distractor removal, infants who had MDO showed faster weight gain than their age-matched peers.

Regional differences in temporomandibular joint inflammation in patients with juvenile idiopathic arthritis: a dynamic post-contrast magnetic resonance imaging study.

The purpose was to determine whether there are regional differences in temporomandibular joint (TMJ) inflammation in patients with juvenile idiopathic arthritis (JIA). This was a retrospective study of all patients with dynamic, contrast-enhanced magnetic resonance imaging through the TMJs at Massachusetts General Hospital between January 2015 and July 2016. The patient cohort included those with a history of JIA and control patients who underwent MRI for other routine clinical purposes. TMJ inflammation was quantified as the difference between post-gadolinium and pre-gadolinium articular T1 signal intensity normalized to post-gadolinium signal intensity of the longus capitis muscle. TMJ enhancement profiles were generated for the lateral, central, and medial portions of the TMJ. Regional differences in TMJ enhancement were investigated using basic descriptive statistics. Medial edge enhancement of the TMJs was highest in symptomatic JIA joints, followed by asymptomatic JIA, then control joints. Medial edge enhancement was a significant discriminator between symptomatic JIA TMJs and control joints (P = 0.0001), between symptomatic and asymptomatic JIA TMJs (P = 0.0003), and between asymptomatic JIA TMJs and controls (P = 0.0019). A shift in distribution of TMJ enhancement towards the medial edge that was seen uniquely in both asymptomatic and symptomatic JIA TMJs compared to control joints was found. This suggests a pattern of worsening medial edge inflammation with disease.

A comparison of airway interventions and gastrostomy tube placement in infants with Robin sequence.

The purpose of this study was to evaluate feeding impairment following non-operative or operative management of airway obstruction in a large series of infants with Robin sequence (RS) by rate of G-tube placement. A retrospective study was conducted at Boston Children's Hospital including 225 patients (47.1% female) with RS treated between 1976 and 2018. Subjects were grouped by intervention required for successful management of airway obstruction: non-operative only (n = 120), tongue-lip adhesion (TLA, n = 75), mandibular distraction osteogenesis (MDO, n = 21), or tracheostomy (n = 9). The operative group had a higher rate of G-tube placement (58.1%) than the non-operative group (28.3%, P < 0.0001). Subjects in the TLA and tracheostomy groups had higher odds of G-tube placement than subjects in the MDO group: odds ratio (OR) 5.5 (95% confidence interval (CI) 1.8-17.3, P = 0.004) and OR 27.0 (95% CI 3.2-293.4, P = 0.007), respectively. Syndromic patients and those with gastrointestinal anomalies also had higher odds of G-tube placement: OR 3.5 (95% CI 1.7-7.2, P = 0.001) and OR 5.9 (95% CI 1.6-21.0, P = 0.007), respectively. Infants with RS who require an airway operation and those with a syndromic diagnosis or gastrointestinal anomalies are more likely to require placement of a G-tube. Of the operative groups, MDO was associated with the lowest G-tube rate, compared to TLA and tracheostomy.

Precise osteotomies for mandibular distraction in infants with Robin sequence using virtual surgical planning.

Mandibular distraction osteogenesis (MDO) has become the first-line operation in many centers for the management of obstructive sleep apnea (OSA) in infants with (Pierre) Robin sequence (RS) not relieved by non-surgical approaches. Preoperative virtual surgical planning (VSP) may improve precision and decrease complications for this operation. This article reports a retrospective study of RS infants who underwent MDO for OSA using preoperative VSP and three-dimensionally printed cutting guides performed by one surgeon. Seventeen subjects who had MDO at a mean age of 87±96days were included. Maxillofacial computed tomography scans were obtained 15±7days prior to MDO. Osteotomy designs included linear (n=4, 23.5%), inverted-L (n=11, 64.7%), and multi-angular (n=2, 11.8%). Cutting guides were used successfully and osteotomies were created as planned in all cases. Devices were removed 67±15.6days after placement. Bone formation in the distraction gap was seen in all cases at device removal. All patients had successful airway outcomes. There were no major and four minor complications during the follow-up period of 458±267 days. In conclusion, MDO is a successful procedure for the management of OSA associated with RS in infants, and VSP facilitates its precise design and execution.

Optimization of Quantitative Dynamic Postgadolinium MRI Technique Using Normalized Ratios for the Evaluation of Temporomandibular Joint Synovitis in Patients with Juvenile Idiopathic Arthritis.

BACKGROUND AND PURPOSE: MR imaging has been shown to be useful in the diagnosis of juvenile idiopathic arthritis of the temporomandibular joint. Prior MR imaging approaches have relied mainly on the subjective interpretation of synovial enhancement as a marker for synovial inflammation. Although, more recently, several attempts have been made to quantify synovial enhancement, these methods have not taken into account the dynamic enhancement characteristics of the temporomandibular joint and the effect of sampling time. Our aim was to develop a clinically feasible, reproducible, dynamic, contrast-enhanced MR imaging technique for the quantitative assessment of temporomandibular joint synovitis in patients with juvenile idiopathic arthritis and to study the effect of sampling time on the evaluation of synovitis. MATERIALS AND METHODS: This was a retrospective study of all patients who had dynamic, contrast-enhanced coronal T1 3T MR imaging through the temporomandibular joint at our institution between January 1, 2015, and July 8, 2016. Patients in this cohort included those with a history of juvenile idiopathic arthritis and control patients who underwent MR imaging for other routine, clinical purposes. Synovial enhancement was calculated for each temporomandibular joint using 3 different types of equations termed normalization ratios. The enhancement profiles generated by each equation were studied to determine which provided the best discrimination between affected and unaffected joints, was the least susceptible to sampling errors, and was the most clinically feasible. RESULTS: A ratio of synovial enhancement (defined as the difference between the postgadolinium and the pregadolinium T1 signal of the synovium) to the postgadolinium signal of the longus capitis provided the best discrimination between affected and unaffected joints, the least susceptibility to sampling error, and was thought to be the most clinically feasible method of quantification of synovial inflammation. Additional synovial enhancement ratios studied did not provide the same level rates of discrimination between the affected and unaffected joints and were thought to be too temporally variable to provide reliable clinical use. CONCLUSIONS: We provide a robust, reproducible, dynamic gadolinium-enhanced MR imaging technique for the quantitative assessment of temporomandibular joint synovitis in patients with juvenile idiopathic arthritis.

Accuracy of three-dimensional soft tissue prediction for Le Fort I osteotomy using Dolphin 3D software: a pilot study.

Three-dimensional (3D) soft tissue prediction is replacing two-dimensional analysis in planning for orthognathic surgery. The accuracy of different computational models to predict soft tissue changes in 3D, however, is unclear. A retrospective pilot study was implemented to assess the accuracy of Dolphin 3D software in making these predictions. Seven patients who had a single-segment Le Fort I osteotomy and had preoperative (T0) and >6-month postoperative (T1) cone beam computed tomography (CBCT) scans and 3D photographs were included. The actual skeletal change was determined by subtracting the T0 from the T1 CBCT. 3D photographs were overlaid onto the T0 CBCT and virtual skeletal movements equivalent to the achieved repositioning were applied using Dolphin 3D planner. A 3D soft tissue prediction (TP) was generated and differences between the TP and T1 images (error) were measured at 14 points and at the nasolabial angle. A mean linear prediction error of 2.91±2.16mm was found. The mean error at the nasolabial angle was 8.1±5.6°. In conclusion, the ability to accurately predict 3D soft tissue changes after Le Fort I osteotomy using Dolphin 3D software is limited.

Comparison of time required for traditional versus virtual orthognathic surgery treatment planning.

Virtual surgical planning (VSP) is a tool for predicting complex surgical movements in three dimensions and it may reduce preoperative laboratory time. A prospective study to compare the time required for standard preoperative planning versus VSP was conducted at Massachusetts General Hospital from January 2014 through January 2015. Workflow data for bimaxillary cases planned by both standard techniques and VSP were recorded in real time. Time spent was divided into three parts: (1) obtaining impressions, face-bow mounting, and model preparation; (2) occlusal analysis and modification, model surgery, and splint fabrication; (3) online VSP session. Average times were compared between standard treatment planning (sum of parts 1 and 2) and VSP (sum of parts 1 and 3). Of 41 bimaxillary cases included, 20 were simple (symmetric) and 21 were complex (asymmetry and segmental osteotomies). Average times for parts 1, 2, and 3 were 4.43, 3.01, and 0.67h, respectively. The average time required for standard treatment planning was 7.45h and for VSP was 5.10h, a 31% time reduction (P<0.001). By eliminating all or some components of part 1, time savings may increase to as much as 91%. This study indicates that in an academic setting, VSP reduces the time required for treatment planning of bimaxillary orthognathic surgery cases.