Three-dimensional airways volumetric analysis before and after fast and early mandibular osteodistraction

Prospective cohort study on facial profile changes in infants with Robin sequence and healthy controls

BACKGROUND

Various conservative and surgical approaches exist to treat Robin sequence (RS), but their effects on facial profile and mandibular catch-up growth are unclear. A functional treatment concept, used in our centre for 25 years, includes an individualized palatal plate with a velo-pharyngeal extension and intensive feeding training.

METHODS

We performed a prospective study to objectively describe facial profiles in infants with RS treated with the above concept. Infants with isolated RS were admitted to our tertiary perinatal and national referral centre for craniofacial malformations between May 2018 and Nov 2019. Infants with RS received 3D-photographs during clinically indicated visits. Healthy controls were recruited from Dec 2018 to Sep 2019 and received 3D-photographs every 3 months. The digitally measured jaw index (JI), defined as alveolar overjet (O) x maxillary arch (U)/mandibular arch (L), and the soft tissue reference points A'-point, Nasion', B'-point angle (ANB'), describing the relative position of maxilla to mandible, were evaluated. Linear mixed models were used to examine time trajectories in JI and ANB'.

RESULTS

A total of 207 3D images, obtained in 19 infants with RS and 32 controls, were analysed. JI and ANB' decreased over time in both groups [for JI - 0.18 (95% CI - 0.25 to - 0.10); for ANB': - 0.40° per month [(95% CI - 0.48 to - 0.32)]] but remained lower in controls [for JI - 2.5 (95% CI - 3.2 to - 1.8); for ANB'-1.7° (95% CI - 2.4 to - 1.0)]. Also, the ANB' model showed a significant effect of the interaction term diagnosis x age.

CONCLUSIONS

Based on longitudinal 3D images, we describe changes in objective parameters of facial profile in infants with and without RS during the first year of life. Our findings indicate catch-up growth in infants treated for RS. Video Abstract.

Does distraction osteogenesis improve the airway volume and quality of life of obstructive sleep apnoea patients secondary to temporomandibular joint ankylosis?

Temporomandibular joint (TMJ) ankylosis leads to mandibular micrognathia that severely collapses the upper airway causing obstructive sleep apnoea (OSA), resulting in deterioration and compromise in the quality of life (QoL) of patients. In this study, we aimed to calculate airway volume changes, apnoea-hypopnoea index (AHI), and improvement in quality of life before and after distraction osteogenesis (DO). Fourteen Patients with OSA secondary to TMJ ankylosis at a mean (SD) age of 17.5 (5.43) years were enrolled in this prospective study. Multivector mandibular distractors were used in all patients following the standard Ilizarov distraction protocol with a mean (SD) anteroposterior distraction of 16.21 (4.37) mm and a consolidation period of 116.92 (14.35) days. The patients were followed up for six months. A polysomnography test (PSG) was done to quantify AHI and a low-dose computed tomographic scan was done to calculate airway volume using Dolphin medical imaging software pre and post-DO. The QoL of the patients was calculated using the OSA-18 questionnaire. Results analysis depicted that the mean (SD) preoperative AHI was 51.44 (37.99)/h which was improved to 9.57 (9.74)/h (p = 0.001) after DO. Airway volume was calculated on Dolphin software before and after DO showed a significant improvement in airway volume by 121.12% (98.30)%. Similarly, the OSA-18 questionnaire showed significant improvement in QoL from severe to normal. This study suggested that DO increases the corpus length of the mandible, leading to an increment in airway volume, which improves the QoL.

Complications of Mandibular Distraction Osteogenesis in Infants with Isolated Robin Sequence

Mandibular Distraction Osteogenesis (MDO) is now the preferred procedure to alleviate airway obstruction in infants with severe Robin Sequence (RS). However, there have been very few studies investigating complications related to MDO surgery performed on patients affected by isolated RS. In this study, age at distraction, weight at distraction, preoperative intubation, repeat MDO and complications associated with MDO were included as variables. Minor, moderate and major problems were evaluated and recorded as surgical site infections (SSI), injuries to the facial nerve, self-extinction hypertrophic scars, temporomandibular joint ankylosis, device failures, early ossification and fibrous non-union. One hundred and fifty one patients with isolated RS were included. At distraction, the mean age was 72 days (12-540 days) and the mean weight was 4.05 kg (2.4-12.2 kg). Only one patient needed tracheostomy after MDO, and none required further distraction. Ultimately, the complication rate was 15.23%, and there was a total of 7.95% minor, 9.27% moderate and 0% major complications. Minor incidents included surgical site infection (SSI) managed with antibiotics taken orally (n = 8), neuropraxia in the VII cranial nerve (CN) (n = 1), and hypertrophic scarring (n = 3). Incidents reported as moderate were SSIs managed with intravenous antibiotics (n = 9), incision and drainage (n = 3) and self-extubation (n = 2). There was no case of TMJ ankylosis. There were no cases of early or premature ossification, fibrous non-union and device fracture. In conclusion, MDO is an effective and appropriate management technique for infants with isolated RS and severe airway obstruction. Infections at the surgery site accounted for the vast majority of the complications. Further investigations may be needed to determine the long-term consequences of MDO.

Changes in Hyoid Bone Position before and after Distraction Osteogenesis in Infants with Robin Sequence

PURPOSE

To study the changes of hyoid position in infants with Robin sequence before and after mandibular distraction osteogenesis, and to explore the related factors.

MATERIAL AND METHODS

Twenty-six infants with Robin sequence underwent bilateral mandibular distraction osteogenesis from May 2016 to April 2020. Three-dimensional computed tomography data of patients before and after surgery were analyzed with Materialise Mimics 17.0. Changes in the three-dimensional position of the hyoid bone were studied.

RESULTS

The angle between the long axis of the tongue body and hard palate plane, and the angle between the long axis of the tongue body and mandibular plane were significantly decreased after surgery than before surgery. The hyoid bone-cranial base vertical distance, hyoid bone-mental point distance, and hyoid bone-epiglottis distance were significantly increased after surgery. The differences in the above-mentioned data were statistically significant (P < 0.05). Changes in the angle between the long axis of the tongue body and the hyoid bone-mental point line correlated with changes in the position of the hyoid bone relative to the cervical spine (P = 0.006). Postoperatively, the hyoid bone moved forward and the increase in the hyoid bone-mental point osseous distance interval (41.28%) was significantly greater than the increase in the hyoid bone-epiglottis distance (18.73%). Differences in the total mandibular length and the hyoid bone-cranial base vertical distance are related to the age at the operation (P < 0.05). The younger the age at the time of surgical intervention, the greater the difference before and after surgery for the same follow-up interval.

CONCLUSIONS

The three-dimensional direction of the hyoid bone changes after the distraction osteogenesis of the mandible, and the hyoid bone moves downward and forward. Because the mandibular length and airway changed, the relative positions of the long axis of the tongue body on the sagittal plane rotated clockwise.

Effects of Mandibular Distraction Osteogenesis on Three-Dimensional Upper Airway Anatomy in Newborns Affected by Isolated Pierre Robin Sequence

Background

Effective airway management is critical to Pierre Robin Sequence treatment. The goal of this study is to assess the three-dimensional changes in airway size and shape in 117 newborns with isolated Pierre Robin sequence who underwent mandibular distraction osteogenesis.

Methods

During the study period (11/29/2016 to 11/26/2019), 117 newborns affected by isolated Pierre Robin sequence met the inclusion criteria for the present study. All 117 included patients underwent linear distraction. Demographic variables were recorded and analyzed. Cone-beam computed tomography were performed before and after mandibular distraction osteogenesis. A systemic quantitative three-dimensional analysis of size and shape of upper airway was performed.

Results

The mean age was 71 day (range 12 to 213). The mean weight was 3.9 kg (range 2.3-6.8). A total of 53 patients are female and 64 are male. When the distraction device was removed, the upper and lower jaws were symmetrically aligned. Pre- and post-distraction comparison clearly showed osteogenesis. For the size of the upper airway, airway volume, anteroposterior dimension of the retroglossal airway, lateral dimension of retroglossal airway, minimum retropalatal area, minimum retroglossal area, average cross-sectional area and minimum cross-sectional area increased significantly after mandibular distraction osteogenesis (P < 0.001). However, the airway length did not change significantly (P > 0.05). For the shape of the upper airway, the lateral/anteroposterior ratio in the retroglossal region and the ratio of the retropalatal airway diameter to the retroglossal airway diameter significantly decreased after mandibular distraction osteogenesis (P < 0.001). The airway uniformity significantly increased after mandibular distraction osteogenesis (P < 0.001).

Conclusion

Mandibular distraction osteogenesis for isolated Pierre Robin sequence improved size and shape of the upper airway, further confirming mandibular osteogenesis distraction as an effective surgical modality to address the airway obstruction in newborns affected by isolated Pierre Robin sequence. Cone-beam computed tomography scanning and analysis can serve as a safe and effective examination modality for upper airway applications of PRS newborns.

The influences of distraction osteogenesis therapy on airway morphology in patients with craniofacial microsomia

The aim of this study was to explore how mandibular distraction osteogenesis influences morphological changes in the oropharynx and laryngopharynx. This was a retrospective study of airway parameter measurements in CFM patients undergoing mandibular distraction osteogenesis treatment. The indication for surgical treatment was the obvious facial asymmetry. Mimics 17.0 (Materialise Inc., Belgium) was used to build 3D models of the oro- and laryngopharynx. The minimum cross-sectional area (CSA), mean CSA, volume, length, and surface area were measured in the 3D models. All data were entered into SPSS v. 23.0 (SPSS Inc. USA), with statistical differences assessed pre- and postoperatively using the Wilcoxon test. Thirty-two patients diagnosed with CFM were included in this study. Five were classified as type IIa, 21 as type IIb, and six as type III, using the Pruzansky-Kaban classification. The average age of the patients was 8.34 years; 14 were females and 18 were males. The average traction time was 35.59 days and the average length of traction was 35.81 mm. The total volume of the airway was significantly increased after MDO (p = 0.001). In the oropharynx and laryngopharynx segments, the mean CSA, minimum CSA, and surface area were statistically significantly different. According to the results, expansion of oropharynx and laryngopharynx were evident after MDO. Mandibular distraction osteogenensis (MDO) can expand the volume of the oropharynx and laryngopharynx. Therefore, MDO can be considered a clinically useful treatment for changing the structure of the oropharynx and laryngopharynx.

Floating Bone Phenomenon in Pierre Robin Sequence

After a failed mandibular osteodistraction, the wrong positioned mandible of a few patients with Pierre Robin sequence returned in the most functional position and regained a proper symmetry, without external intervention. The study aims to explain this self-adjustment and introduce the floating bone phenomenon.The inclusion criteria were severe micrognathia, Fast and Early Mandibular Distraction Osteogenesis protocol, postoperative mandibular wrong positioning, presurgery, immediate postsurgery, and long-term computed tomography scan. Five patients were included. The considered parameters were the distance between mandibular dental centerline and midsagittal facial axis, the rotation of the mandibular body, the magnitude of elongation, and the lowering of the mandibular body.Three patients went from a decentralization >4 mm in the activation phase to a normalization of the said value in the follow-up. In the same period, the interincisal point of 2 patients moved respectively from 0.5 mm on the left and 0.8 mm on the right to 1.2 mm and 1.6 mm on the right, respectively. The rotation of the mandibular body was meanly 25.6° among all patients. The mean value of the distraction was 14.1 mm. A difference of about 4.4 mm between the left and the right side was measured. The lowering of the mandible varied between 2.8 and 12.6 mm.All patients improved their symmetry. Four of them improved in all the measured parameters, while 1 patient presented a worsening in the decentralization of the interincisal point.The floating bone phenomenon could break new grounds in the management of patients with Pierre Robin sequence.

Imaging characteristics of the mandible and upper airway in children with Robin sequence and relationship to the treatment strategy

Some patients with Robin sequence (RS) may respond to conservative therapy, while others require surgery; however, there are currently no objective anatomical criteria to gauge surgical indication. The purpose of this study was to explore the imaging characteristics of the mandible and upper respiratory tract in children with RS and examine how individual morphometric parameters influence the treatment strategy. Cone beam computed tomography (CBCT) images were obtained from 57 children with RS. Twenty parameters were measured as potential surgical indicators. The children were divided into two groups according to surgical requirement: a non-surgical group (26 children) and a surgical group (31 children who underwent mandibular osteodistraction). Differences in the imaging parameters were compared between the groups. The mandibular ramus was shorter bilaterally (left, P = 0.047; right, P = 0.027) and the mandibular body was longer bilaterally (left, P = 0.030; right, P = 0.025) in the surgical group when compared to the non-surgical group. In addition, the mandibular angle bilaterally (left, P = 0.023; right, P = 0.003) and the cross-sectional area at the epiglottis tip (P = 0.010) were smaller in the surgical group. Compared to RS patients receiving conservative treatment, children requiring surgery have specific anatomical features of the mandible and upper airway that can be used as surgical indications.

Dynamical Changes of Mandible and Upper Airway After Mandibular Distraction Osteogenesis in Pierre Robin Sequence

OBJECTIVE

To present the dynamical evaluation of mandible and upper airway size among Chinese infant patients following mandibular distraction osteogenesis in a short-term follow-up and compare predistraction measurements with a normal age- and sex-matched control.

METHODS

All the patients have undergone the computed tomography (CT) scan before mandibular distraction osteogenesis (T0), at the end of the distraction phase (T1), and 3 months after the end of the distraction phase before the distractor removal (T2). A CT analyzing computer software MIMICS was utilized to analyze the anatomic variables of upper airway size and mandible size. All analysis was based on a significance level of 0.05.

RESULTS

Eight patients with Pierre Robin sequence differed mainly in the mandibular body length and the minimum anteroposterior dimension of the retroglossal airway from the control. After mandibular distraction osteogenesis, the mandibular body length and the ramus height both increased significantly, the ramus height also increased after 3 months of consolidation. Only small increase in the airway dimension of the retroglossal area at T2 was observed compared with T1.

CONCLUSION

Mandibular distraction osteogenesis is an effective modality in treating Pierre Robin sequence. Compared with normal control, the main difference may be the length of mandibular body and the area of the retroglossal airway. There may not be an increase in the diameter of airway and the length of mandibular body after 3 months of growth and development in Pierre Robin sequence. Individual surgical plan should be made to gain a better prognosis.

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.

A clinical prediction rule to identify difficult intubation in children with Robin sequence requiring mandibular distraction osteogenesis based on craniofacial CT measures

BACKGROUND

Airway management is challenging in children with Robin sequence (RS) requiring mandibular distraction osteogenesis (MDO). We derived and validated a prediction rule to identify difficult intubation before MDO for children with RS based on craniofacial computed tomography (CT) images.

METHOD

This was a retrospective study of 69 children with RS requiring MDO from November 2016 to June 2018. Multiple CT imaging parameters and baseline characteristic (sex, age, gestational age, body mass index [BMI]) were compared between children with normal and difficult intubation according to Cormack-Lehane classification. A clinical prediction rule was established to identify difficult intubation using group differences in CT parameters (eleven distances, six angles, one section cross-sectional area, and three segment volumes) and clinicodemographic characteristics. Predictive accuracy was evaluated by receiver operating characteristic (ROC) curve analysis.

RESULTS

The overall incidence of difficult intubation was 56.52%, and there was no significant difference in sex ratio, age, weight, height, BMI, or gestational age between groups. The distance between the root of the tongue and posterior pharyngeal wall was significantly shorter, the bilateral mandibular angle shallower, and the cross-sectional area at the epiglottis tip smaller in the difficult intubation group. A clinical prediction rule based on airway cross-sectional area at the tip of the epiglottis was established. Area > 36.97 mm² predicted difficult intubation while area < 36.97 mm² predicted normal intubation with 100% sensitivity, 62.5% specificity, 78.6% positive predictive value, and 100% negative predictive value (area under the ROC curve = 0.8125).

CONCLUSION

Computed tomography measures can objectively evaluate upper airway morphology in patients with RS for prediction of difficult intubation. If validated in a larger series, the measures identified could be incorporated into airway assessment tools to guide treatment decisions. This was a retrospective study and was granted permission to access and use these medical records by the ethics committee of Guangzhou Women and Children's Medical Center.

TRIALS REGISTRATION

Registration No. ChiCTR1800018252, NaZhang, Sept 7 2018.

Neonatal Functional Treatment for Pierre Robin Sequence

Objective

Pierre Robin Sequence (PRS) is a heterogeneous pathological condition characterized by the coexistence of micrognathia, glossoptosis, and cleft palate, resulting in upper airway tract obstruction. Among the treatment modalities, the orthodontic approach is one part of the comprehensive care of those patients and will be present in the treatment modalities during all the growth period of the child.

Methods

All patients with PRS observed in the period 2013-2017 were treated with a definite functional approach. The results were retrospectively analyzed with regard to functional outcome, total treatment time, and number of plates provided for a single patient.

Results

In all the patients, the indicated treatment protocol has been applied as early impression and plate supply, stimulation of bottle feeding with the use of the plate, eventual substitution of the plate if no more adequate to the transverse and sagittal growth of the palate, and continuing the use until the surgical closure of the cleft. All the patients showed a positive outcome to the proposed treatment approach, evaluated with regard to the incidence of feeding improvement and weight gain, to the limit for the surgical phase, in the absence of adverse effects.

Conclusion

The use of a functional obturator plate, removing functional alterations to mandibular growth, reduces and, in some cases, eliminates the need for surgical intervention. As also stated in the literature, if despite the presence of the plate nutritional problems persist, immediate different surgical approaches, mainly mandibular osteodistraction, become necessary.