Mid-Term Dental and Nerve-Related Complications of Infant Distraction for Robin Sequence:

A Comprehensive Approach to Robin Sequence

Robin sequence is a congenital condition characterized by micrognathia, glossoptosis, and airway obstruction with or without cleft palate. The condition is best managed by a multidisciplinary team proficient in treating the complex pediatric airway, including pediatricians, speech and feeding specialists, and surgeons. Conservative treatment includes prone positioning, nasopharyngeal airways, supplemental oxygen, and feeding support to maintain a patent airway and promote infant growth. For infants requiring further intervention, the tongue may be repositioned anteriorly through surgical tongue-lip adhesion or nonsurgical techniques including the orthodontic airway plate. Mandibular distraction osteogenesis is used in severe cases with the goal to avoid tracheostomy.

True Incidence of Marginal Mandibular Nerve Palsy following Neonatal Mandibular Distraction Osteogenesis

BACKGROUND

In children with Pierre Robin sequence (PRS), mandibular distraction osteogenesis (MDO) is routinely performed to alleviate airway obstruction; however, it involves risk of injury to the marginal mandibular nerve (MMN). The authors hypothesize that MMN palsy incidence following MDO, reported at 1% to 15%, is underestimated. This study investigates the true incidence of MMN palsy after MDO to better guide follow-up care and improve treatment of this complication.

METHODS

A retrospective review of PRS patients who underwent MDO at a single, tertiary pediatric hospital between September of 2007 and March of 2021 was conducted. Patients who underwent MDO younger than 1 year of age and had postoperative clinical evaluations detailing MMN function were included. Logistic regression analysis was performed to investigate predictors of MMN injury.

RESULTS

Of 93 patients who underwent MDO, 59.1% met inclusion criteria, 56.4% were female, 43.6% were syndromic, and average age at MDO was 1.52 ± 2.04 months. The average length of mandibular distraction was 17.3 ± 4.36 mm, the average duration of intubation was 6.57 ± 2.37 days, and the average time until hardware removal was 111.1 ± 23.6 days. Sixteen patients (29.1%) presented with permanent MMN dysfunction, consisting of 8 patients with bilateral weakness and 8 with unilateral weakness. An additional 5 patients (9.1%) presented with transient MMN weakness that resolved within 1 year. Average length of follow-up postoperatively was 6.02 years, and no significant predictors of nerve injury were found.

CONCLUSION

In this 14-year review of patients with PRS who underwent MDO, 38.2% demonstrated evidence of MMN palsy (permanent, 29.1%; transient, 9.1%), which is much greater than previously described.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

Focused Investigation of Facial Nerve Dysfunction After Mandibular Distraction Osteogenesis for Robin Sequence

Facial nerve dysfunction (FND) is a well-recognized but poorly documented complication of mandibular distraction osteogenesis (MDO) for Robin sequence (RS). This study aims to document the authors' experiences with FND and identify risk factors associated with this adverse event. A retrospective review of a prospectively gathered database was performed to identify patients with RS who underwent MDO at the authors' institution from March 2016 to June 2023. The authors included all infants with at least 3 months of follow-up after device removal. Data collected included patient demographics, incidence, laterality and onset of FND, and time to resolution. Thirty-six patients met the inclusion criteria. The median age at MDO was 2.7 (interquartile range: 0.7, 129) months. The median latency, distraction, and consolidation phases were 3.0 days, 17.5 days, and 77.5 days, respectively. The median length of distraction was 19.8 (interquartile range: 11, 30) mm. Thirteen infants (36.1%) demonstrated FND. While the majority (n = 10, 27.8%) experienced temporary palsy with a mean time to resolution of 98.6 (± 124.3) days, 3 infants (8.3%) had persistent FND at a mean of 29.3 (±35.6) months after hardware removal. The majority of FND occurred during the distraction phase and involved the marginal mandibular nerve. The current study demonstrated that over 1/3 of patients with RS experience FND after MDO. Most cases of FND were transient and occurred during the active distraction phase.

Comprehensive Long-Term Outcomes Following Mandibular Distraction Osteogenesis

OBJECTIVE

To describe long-term outcomes and complications following mandibular distraction osteogenesis (MDO) in a diverse patient cohort.

DESIGN

Cross-sectional study.

SETTING

Single tertiary-care pediatric center.

PATIENTS

Forty-eight patients previously undergoing MDO with minimum 4-year follow-up.

MAIN OUTCOME MEASURES

Respiratory outcomes, feeding patterns, dental development, motor/sensory nerve function, temporo-mandibular joint function, and postsurgical scarring.

RESULTS

Forty-six patients with a median age of 7 years were evaluated. Of 20 nonsyndromic patients, none required additional airway procedures, none required continuous positive airway pressure (CPAP) during sleep, and 19 (95%) fed exclusively by mouth. Among 26 syndromic patients, 7 (27%) required CPAP and 8 (31%) were tube fed. Permanent first molar differences were seen in the majority of subjects; patterns of damage interfering with function were more common in syndromic (13/28, 46%) compared to nonsyndromic (5/24, 21%; P = .014) subjects. MDO prior to age two was associated with more frequent and worse dental damage (P = .001). Inferior alveolar nerve and marginal mandibular nerve function were fully intact in 37 (80%) and 39 (85%) of patients, respectively. Three patients (6%), all with associated genetic syndromes, demonstrated severe nerve impairment. By the Vancouver scar scale, ≥ 80% of surgical scars were rated in the most favorable category for each quality assessed. Temporomandibular joint dysfunction was rare.

CONCLUSIONS

MDO shows highly favorable long-term respiratory, feeding, nerve, and scar outcomes in nonsyndromic patients, although permanent molar changes not precluding tooth viability are commonly seen. Patients with associated syndromes demonstrate respiratory and feeding benefits, but higher rates of dental and nerve abnormalities.

Diagnosis and Early Management of Robin Sequence

The results of a survey of twenty-four neonatal units in the United Kingdom and Ireland are presented. A structured ten-item questionnaire was used, and demonstrated the variation in how infants with RS are diagnosed and managed. Notably, the survey revealed that a minority of infants were diagnosed antenatally. There were significant discrepancies in diagnostic criteria used and 79% of the units referred the patients to tertiary services. A preference for minimally invasive approaches to managing upper airway obstruction, such as a trial of prone positioning before progressing to a nasopharyngeal airway, was reported by 96% of the centers. A narrative review was undertaken which discusses the current practices for diagnosis and early management of Robin sequence (RS). The challenges of antenatal diagnosis, strategies to enhance outcomes through early detection and controversies surrounding the management of neonatal upper airway obstruction associated with RS are included. The results of the survey and our comprehensive review of the literature emphasize that there remains uncertainty regarding the best approach to treating Robin sequence.

Does Mandibular Distraction Osteogenesis for Robin Sequence Create Altered Craniofacial Morphology and Disrupt Tooth Development?

BACKGROUND

Robin Sequence (RS) infant patients may require mandibular distraction osteogenesis (MDO) to improve airway. The distracted mandible may grow vertically and the developing dentition may be disrupted.

PURPOSE

The study purpose was to measure the association of MDO on craniofacial morphology and tooth development in RS subjects.

STUDY DESIGN, SETTING, SAMPLE

This was a retrospective cohort study of RS infants treated with or without MDO. Inclusion criteria were RS diagnosis, complete imaging, and treatment at our pediatric regional hospital. Exclusion criteria were treatment elsewhere and insufficient imaging.

EXPOSURE VARIABLE

Exposure was airway management; subjects were grouped by use of MDO or not. Subjects were compared to age-matched normal infants presurgically and to age-matched normal controls at follow-up.

MAIN OUTCOME VARIABLES

Main outcome variables were craniofacial morphology measured using cephalometric gonial angle and ramus height to mandibular body length ratio presurgically (T1), postsurgically (T2), and at the mixed dentition (T3). Disrupted tooth development was assessed by absence/abnormality of teeth on radiographs at T3.

COVARIATES

Covariates were age, sex, body mass index, comorbidities, and cephalometric measurements.

ANALYSES

Appropriate univariate, bivariate, and regression models were computed, and significance level was set at P < .05.

RESULTS

The sample contained 14 RS-MDO subjects with median age of 1.1 months and 10 (71.4%) were female. Presurgery, RS-MDO subjects had significantly more obtuse gonial angles (145° vs 137°, P = .04) and shorter mandibular bodies (32 vs 41 mm, P < .01) than the 37 unaffected controls. Increased ramus height (P < .01) and mandibular body length (P < .01) and forward rotation of the mandible were seen in 12 subjects with post-MDO imaging compared to their presurgical condition. At mixed dentition, 12 post-MDO subjects had more obtuse gonial angles (P < .01) and steeper mandibular planes (P < .01) than 19 non-MDO RS subjects. Both RS groups had different cephalometric values and more vertical measures than matched cephalometric norms. Thirty-one percent of 12 RS-MDO subjects had ≥1 teeth with abnormal development compared to none of 19 RS subjects without MDO (P = .02).

CONCLUSION AND RELEVANCE

MDO increased mandibular size in infants but can disrupt the developing dentition. Postdistraction growth may result in more vertical mandibular morphology with large gonial angles.

Computerized Surgical Planning for Mandibular Distraction Osteogenesis

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

Mandibulotomy Technique and Permanent Molar Injury After Mandibular Distraction Osteogenesis in Infants

OBJECTIVE

The risk that mandibular distraction osteogenesis (MDO) poses to the developing mandibular dentition is well-known; however, less is understood about how the choice of instrumentation used for mandibular osteotomy might affect the development of permanent molars.

METHODS

Retrospective chart review examining infants with micrognathia who underwent MDO from 2010 to 2018 at a single tertiary care children's hospital using external, multivector devices. The first and second permanent mandibular molars were radiographically examined years after surgery to determine whether osteotomy cutting techniques affect the risk of injury to the permanent dentition.

RESULTS

Thirty-seven infants and children underwent MDO from 2010 to 2018. Follow-up dental radiographs were available for 17 patients; 6 patients were excluded based on the use of preoperative computed tomography, utilization of virtual surgical planning technology, use of buried internal distractors, or older age at the time of distraction surgery. This yielded a total of 11 patients who underwent MDO with external hardware without virtual surgical planning representing 22 osteotomies. Sixteen osteotomies were performed using a side-cutting burr and 6 with a piezoelectric saw. The median age at distraction surgery was 3 weeks. The rate of an abnormal permanent first or second mandibular molar finding per osteotomy was 88% (14/16) in the side-cutting group versus 17% (1/6) with the piezoelectric technique (P = 0.004).

CONCLUSION

Mandibular distraction osteogenesis risks injury to the mandibular molars; however, this study suggests a significant risk reduction in molar injury if the piezoelectric device is utilized.

Patient-specific distractors for customized mandibular distraction osteogenesis to relieve upper airway obstruction in infants with Pierre Robin sequence

The purpose of this article is to report the author's technique for using patient-specific distractors for customized distraction osteogenesis of the mandible in patients with Pierre Robin sequence and upper airway obstruction. The advantages of virtual planning and patient-specific plates in other aspects of craniomaxillofacial surgery, such as orthognathic and reconstructive surgery, have been reported previously. Similar to patient-specific plates, the theorized advantages of patient-specific distractors in infants with Robin sequence and upper airway obstruction include increased accuracy, decreased operating time, and less morbidity to vital anatomic structures such as the inferior alveolar nerve and developing tooth buds. This technique is novel in using patient-specific distractors in the craniomaxillofacial skeleton.

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.

Transfacial Two-pin External Mandibular Distraction Osteogenesis: A Technique for Neonatal Airway Obstruction from Robin Sequence

Surgical management in those with moderate-to-severe airway obstruction includes tongue-lip adhesion, tracheostomy, and/or mandibular distraction osteogenesis. This article describes a transfacial two-pin external device technique for mandibular distraction osteogenesis, utilizing minimal dissection.

Methods

The first percutaneous pin is transcutaneously placed just inferior to the sigmoid notch parallel to the interpupillary line. The pin is then advanced through the pterygoid musculature at the base of the pterygoid plates, toward the contralateral ramus, and exits the skin. A second parallel pin is placed spanning the bilateral mandibular parasymphysis distal to the region of the future canine. With the pins in place, bilateral high ramus transverse corticotomies are performed. Using univector distractor devices, the length of activation varies, with the goal of overdistraction to achieve a class III relationship of the alveolar ridges. Consolidation is limited to a 1:1 period with the activation phase, and removal is performed by cutting and pulling the pins out of the face.

Results

To guide optimal transcutaneous pin placement, transfacial pins were then placed through twenty segmented mandibles. Mean upper pin (UP) distance was 20.7 ± 1.1 mm from the tragus. The distance between the cutaneous entry of the UP and lower pin was 23.5 ± 0.9 mm, and the tragion-UP-lower pin angle was 118.7 ± 2.9°.

Conclusions

The two-pin technique has potential advantages regarding nerve injury and mandibular growth, given an intraoral approach with limited dissection. It may safely be performed on neonates whose small size may preclude the use of internal distractor devices.

Facial Nerve Dysfunction After Mandibular Distraction Osteogenesis in Patients with Robin Sequence: A Systematic Review and Meta-Analysis

OBJECTIVE

Robin Sequence (RS), characterized by micrognathia, glossoptosis, and upper airway obstruction, is an increasingly recognized diagnosis. An effective surgical intervention is mandibular distraction osteogenesis (MDO). This study analyzes published evidence regarding facial nerve dysfunction (FND) associated with MDO.

DESIGN AND SETTING

According to PRISMA guidelines, a systematic review was carried out with databases queried in June 2019 using MESH terms, or equivalent terms, as follows: "distraction osteogenesis" and "Robin Sequence". A review of original Spanish and English articles, were included. Outcome measures included the prevalence of FND; the affected branches; the rate of permanent vs. transient FND; the use of an internal vs. external device; the daily distraction rate; and finally, the overall distraction length. Subsequently, a meta-analysis was conducted to collate results regarding the prevalence of FND and the factors associated with it.

RESULTS

Of 239 unique studies identified, 19 studies with 729 patients met inclusion criteria; 52 patients developed FND after MDO. A random-effects meta-analysis yielded a pooled prevalence of FND of 6.40%, with moderately heterogeneous studies (I2 = 41%, τ2 = 0.006). Marginal mandibular nerve involvement was most commonly noted. Nine studies reported transient FND, six permanent, one both, and two unspecified. Internal distractors were used in 8 studies and external in 3 and both in 2. Distraction rate was 1.00 to 2.00 mm/day and total distraction length ranged from 13.00 to 22.3 mm. Sample size was the only parameter inversely associated with rate of FND (p = 0.04).

CONCLUSION

This analysis of FND associated with MDO for patients with RS demonstrates a lack of consistent documentation. MDO-associated FND does not appear to be uncommon, and permanent dysfunction can occur. This review underscores the importance of thorough documentation to elucidate the mechanism of FND.

Dental outcomes after neonatal mandibular distraction

PURPOSE OF REVIEW

The aim of this study was to understand dental complications associated with neonatal mandibular distraction and subsequent dental outcomes.

RECENT FINDINGS

Dental injury is often associated with neonatal mandibular distraction osteogenesis. Newer technology offers safer techniques to minimize this risk. Long-term follow up and dental outcomes in permanent dentition are needed to better understand the actual risk associated with the procedure.

SUMMARY

Surgeons performing neonatal mandibular distraction osteogenesis need to understand the associated risks to deciduous and permanent dentition as well as techniques to mitigate this risk.

Mandibular Distraction Osteogenesis in Robin Sequence Using Three-Dimensional Analysis and Planning

SUMMARY

The optimal management of patients with Robin sequence may include neonatal mandibular distraction osteogenesis, which has been used to achieve excellent functional and aesthetic outcomes in appropriate patients. This article and video vignette depict the treatment of micrognathia and airway obstruction secondary to Robin sequence, demonstrating the planning and surgical approach of the senior author (D.M.S.) using mandibular distraction osteogenesis.

Safety of Mandibular Osteotomies in Infants with Pierre Robin Sequence: Computer-Aided Modeling to Characterize the Risks of Various Techniques

BACKGROUND

Mandibular distraction osteogenesis is effective for the correction of severe tongue-based airway obstruction in infants with Pierre Robin sequence. Involved osteotomies may damage developing tooth buds and/or the inferior alveolar nerve. The authors evaluated the theoretical safety of various osteotomy techniques to better define infantile mandibular anatomy using computer-aided modeling.

METHODS

Seven mandibular osteotomy techniques (oblique, inverted-L, multiangular, walking stick, high oblique, vertical/high inverted-L, and horizontal) were simulated using computed tomography studies from infants with Pierre Robin sequence and without other associated conditions. Software was used to manually segment the mandibular bone, inferior alveolar nerve, and tooth buds.

RESULTS

Sixty-five computed tomography scans were included, yielding 130 hemimandibles. The horizontal osteotomy pattern had significantly lower theoretical risk of tooth bud (p < 0.001) and inferior alveolar nerve involvement (p < 0.001) than all other patterns. Osteotomies with high vertical components (i.e., vertical, walking stick, and multiangular) had lower theoretical tooth bud involvement than the more proximal oblique and inverted-L osteotomies (p < 0.001). Average lingula location was measured at a point 65 percent of the mandibular width from anterior mandibular border and 63 percent of the mandibular height from the inferior mandibular border.

CONCLUSIONS

Surgical planning with computed tomography scans can help evaluate an infant's mandibular anatomy to select an osteotomy that reduces morbidity risks. Regardless of technique, tooth buds and the inferior alveolar nerve are often included in osteotomies. The lingula location in this study demonstrates a position more superior and posterior than that previously described.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, V.

Timing and Duration of Facial Nerve Dysfunction After Mandibular Distraction Osteogenesis for Robin Sequence

Objective

Collect data from craniofacial surgeons to analyze mandibular distraction osteogenesis (MDO) protocols, and facial nerve dysfunction (FND) to characterize this common, but poorly documented complication after MDO in infants with Robin Sequence (RS).

Design, Setting, and Participants

A 16-question anonymous survey designed through REDCap was digitally distributed to members of the American Cleft Palate-Craniofacial Association and International Society of Craniofacial Surgery (ISCFS).

Main Outcome Measure(s)

Demographic information, MDO perioperative variables, surgeon experience with FND after MDO for patients with RS, and the timing and duration of FND were analyzed.

Results

Eighty-four responses were collected, with 80 included for analysis. Almost two-thirds of respondent surgeons reported FND as a complication of MDO in patients with RS (51, 63.8%); 58.8% (n   =   47) transient FND and 5% (n   =   4) with permanent facial nerve palsy only. Both transient and permanent FND was documented by 13 (16.3%) respondents. Among respondents, FND was observed immediately following initial device placement/osteotomies in 45.1%, during distraction in 45.1%, during consolidation in 19.6%, and following device removal in 43.1%. Twenty-five of these respondent surgeons reported resolution of FND between 1 and 3 months (53.2%, n   =   25).

Conclusions

FND after MDO in patients with RS was noted by most respondents in this survey study. While most surgeons noted temporary FND, one-fifth reported long-term dysfunction. FND was documented most commonly following device placement/osteotomies or during active distraction. Further research should seek to establish risk factors associated with FND and identify surgical and perioperative prevention strategies

Evaluating Sensory Nerve Outcomes After Horizontal Osteotomy for Mandibular Distraction in Infant Robin Sequence Patients

ABSTRACT

There has yet to be a consensus on the appropriate technique for mandibular distraction in the infant Pierre Robin population nor is their sufficient data on sensory nerve outcomes. The purpose of this study is to validate the safety of the horizontal osteotomy by: (1) determining mandibular foramen location in infant Pierre Robin patients relative to the dentoalveolar plane and (2) evaluate long-term function of the inferior alveolar nerve in previously distracted Pierre Robin patients. Preoperative 3D Computed tomography (CT) scans of Pierre Robin patients < 1 year old were reviewed. 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 was then measured. Semmes-Weinstein monofilaments of the lower lip and chin bilaterally was performed on mandibular distraction patients in clinic. Inclusion criteria was patients >6 years of age having undergone bilateral mandibular distraction at <1 year of age. Fifteen patients' CT studies were examined. The mandibular foramen was consistently below the level of the dentoalveolar plane at an average distance of 4.7 mm. Eight patients were included in the prospective arm. Average age was 12.2. All patients had normal sensation at 2.83 through all areas. The mandibular foramen reliably exists below the dentoalveolar plane. In addition, all patients reviewed postoperatively with >10 years of follow up demonstrated normative sensation. The horizontal corticotomy performed just above the mandibular dentoalveolar plane spares the inferior alveolar nerve in young Pierre Robin patients undergoing distraction.

The Surgical Treatment of Robin Sequence: Neonatal Mandibular Distraction Osteogenesis in the Unfavorable Patient

INTRODUCTION

Neonates with severe Pierre Robin sequence (PRS) can be treated by mandibular distraction osteogenesis (MDO), tongue-lip adhesion, or tracheostomy; however, there is an active debate regarding the indications of MDO in this patient population. Published algorithms identify tracheomalacia, bronchomalacia, laryngomalacia, hypotonic syndromes, and central sleep apnea as contraindications for MDO and indications for tracheostomy, but these comorbidities may exist along a spectrum of severity. The authors propose that appropriately selected neonates with PRS who concurrently express 1 or more of these traditional contraindications may be successfully treated with MDO.

METHODS

The authors performed a 5-year retrospective chart review of all neonates who underwent MDO for treatment of severe PRS. All patients expressed a comorbidity previously identified as an indication for tracheostomy. Pre- and postoperative characteristics were recorded. Apnea/hypopnea index (AHI) before and after MDO were compared using 2-tailed repeated measures t-test.

RESULTS

The authors identified 12 patients with severe PRS and conditions associated with contraindications to MDO: 9 (75.0%) patients had laryngomalacia, 6 (50.0%) patients had tracheomalacia, 2 (16.6%) patients had bronchomalacia, 1 (8.3%) patient had central sleep apnea, and 3 (25.0%) patients had hypotonia. Five (41.7%) patients underwent concurrent gastrostomy tube placement due to feeding insufficiency. Average birthweight was 3.0 kg. Average pre-op AHI was 34.8. Average post-op AHI was 7.3. All patients successfully underwent MDO with avoidance of tracheostomy.

CONCLUSIONS

By employing an interdisciplinary evaluation of patient candidacy, MDO can safely and effectively treat upper airway obstruction and avoid tracheostomy in higher-risk neonatal patients with traditional indications for tracheostomy.

Pediatric Orthognathic Surgery: National Analysis of Perioperative Complications

BACKGROUND

Orthognathic surgery has traditionally been performed after skeletal maturity. Although these procedures are also being performed in children, the implications of earlier intervention and specific risk factors in this younger population remain unknown.

METHODS

The American College of Surgeons National Surgical Quality Improvement Program Pediatric dataset was queried for orthognathic procedures performed in 2018. Complications, readmissions, and reoperations were analyzed with appropriate statistics.

RESULTS

Overall adverse event rate after orthognathic surgery in pediatric patients was 7.8% (n = 22 of 281), which were associated with having any comorbidity (P < 0.001), overall respiratory comorbidities (P = 0.004), structural pulmonary abnormality (P < 0.001), developmental delay (P = 0.035), structural central nervous system abnormality (P < 0.001), and neuromuscular disorder (P = 0.035). Most common complications were excessive bleeding (2.5%), surgical site infection (1.1%), and pneumonia (0.7%). Orthognathic surgery in children below 6 years of age is associated with significantly increased adverse events (P < 0.001), including surgical site infection (P < 0.001), pneumonia (P = 0.022), readmission (P < 0.001), and reoperation (P < 0.001). Le Fort I osteotomies (P < 0.001) and bilateral sagittal split osteotomies (P = 0.009) took significantly longer for older patients in the years of permanent dentition than younger patients in the years of deciduous dentition. Single- and double-jaw procedures in pediatric patients have similarly low adverse events (P all ≥0.130). Interestingly, bilateral sagittal split osteotomies performed before 13.5 years of age were associated with a higher risk of adverse events (P = 0.012), such that these younger patients were 7.1 times more likely to experience adverse events if their procedure was performed earlier.

CONCLUSIONS

Orthognathic surgery is relatively safe, but children in the years of deciduous dentition under 6 years of age have significantly increased risk of adverse events.

Robin Sequence: Neonatal Mandibular Distraction

Pierre Robin sequence is defined by the clinical triad: mandibular hypoplasia, glossoptosis, and airway obstruction. Mandibular distraction osteogenesis (MDO) is a standard treatment of Robin sequence associated with severe airway obstruction and is the only intervention that directly corrects the underlying anatomic pathologic condition. Compared with tongue-lip adhesion, MDO has demonstrated more success in treating airway obstruction in infants with Pierre Robin sequence, including patients with syndromic diagnoses and concomitant anomalies. This article provides a current, comprehensive review of neonatal mandibular distraction and offers treatment guidelines based on a combined surgical experience of more than 400 patients.

Short-term condylar and glenoid fossa changes in infants with Pierre Robin sequence undergoing mandibular distraction osteogenesis

The purpose was to evaluate short-term changes in condylar and glenoid fossa morphology in infants with Pierre Robin sequence (PRS) undergoing early (age <4 months) mandibular distraction osteogenesis (MDO) for the management of severe airway obstruction. Computed tomography data from infants with PRS who had MDO were compared to those of age-matched control infants without facial skeletal dysmorphology. Surface/volume, linear, and angular measurements of the condyle and glenoid fossa were obtained and compared between infants with PRS and controls. Eleven infants with PRS met the inclusion criteria. There were five female and six male subjects with a mean age at the time of MDO of 41±32 days. Prior to MDO, PRS mandibles had a smaller condylar articulating surface area and volume than age-matched control mandibles, with a more laterally positioned condylar axis (P≤0.05). Following MDO, there were significant increases in condylar articulating surface area and volume, approaching those of normal controls, with further lateral translation of the condylar axis (P≤0.05). Condyle and glenoid fossa morphology is largely normalized following early MDO in infants with PRS. The condylar axis translates laterally as a result of MDO; this change is not observed with mandibular growth in infants without PRS.

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.

Part II: Temporomandibular Joint (TMJ)-Regeneration, Degeneration, and Adaptation

PURPOSE OF REVIEW

Elucidate temporomandibular joint (TMJ) development and pathophysiology relative to regeneration, degeneration, and adaption.

RECENT FINDINGS

The pharyngeal arch produces a highly conserved stomatognathic system that supports airway and masticatory function. An induced subperiosteal layer of fibrocartilage cushions TMJ functional and parafunctional loads. If the fibrocartilage disc is present, a fractured mandibular condyle (MC) regenerates near the eminence of the fossa via a blastema emanating from the medial periosteal surface of the ramus. TMJ degenerative joint disease (DJD) is a relatively painless osteoarthrosis, resulting in extensive sclerosis, disc destruction, and lytic lesions. Facial form and symmetry may be affected, but the residual bone is vital because distraction continues to lengthen the MC with anabolic bone modeling. Extensive TMJ adaptive, healing, and regenerative potential maintains optimal, life support functions over a lifetime. Unique aspects of TMJ development, function, and pathophysiology may be useful for innovative management of other joints.

Virtual Surgical Planning for Mandibular Distraction in Infants with Robin Sequence

Mandibular distraction osteogenesis (MDO) successfully relieves obstructive sleep apnea in many infants with Robin sequence. Preoperative virtual surgical planning and fabrication of three-dimensionally printed cutting guides may lead to further improvements in the MDO technique and decrease the risk for damage to adjacent structures such as developing teeth and the inferior alveolar nerve. This report presents an algorithm for virtual surgical planning and three-dimensionally printing of cutting guides for MDO in infants with RS.