Distraction Osteogenesis in the Pediatric Population

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.

Polysomnography-guided mandibular distraction osteogenesis in Pierre Robin sequence patients

STUDY OBJECTIVES

Craniofacial malformations with micrognathia cause high grades of obstructive sleep apnea (OSA) measured by polysomnography (PSG). Mandibular Distraction Osteogenesis (MDO) is a novel procedure for upper airway obstruction (UAO) relief. Our primary objective was to describe the utilization of PSGs to improve obstruction in patients undergoing mandibular distraction.

METHODS

This is a retrospective study. Patients with micrognathia and severe UAO, presenting with severe OSA diagnosed by PSG, were included from a single tertiary care center between 2015-2019. PSGs were done: (1) prior to surgery, (2) once cosmetic goal was achieved (Post-Op 1) (3) if residual moderate-to-severe OSA was seen, every 2 nights until mild or no OSA was achieved (Post-Op 2).

RESULTS

Thirteen patients were included. The median age at surgery was 1.1months (10 days-3 months). All thirteen patients had baseline severe OSA, with a median obstructive apnea-hypopnea index (OAHI) of 33 events/h and a median O₂ nadir of 73%. Post-Op 1 PSG was done at a median of 6 days after surgery. Median first post-operative OAHI in all 13 patients was 6.8 events/h, with a median O₂ nadir of 87%. A median additional distraction of 3 mm was needed beyond the traditionally recommended advancement. Long term follow-up studies at or after 1year were done in 5 patients, all showing persistent non-severe OSA.

CONCLUSIONS

This is the first case-series utilizing PSGs as a guide for MDO in patients with micrognathia showing the need for jaw over-correction to achieve resolution of OSA.

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

A New Orthodontic-Surgical Approach to Mandibular Retrognathia

(1) Background: Mandibular deficiency is one of the most common growth disorders of the facial skeleton. Recently, distraction osteogenesis has been suggested as the treatment of choice for overcoming the limitations of conventional orthognathic surgery; (2) Methods: A new custom-manufactured dental-anchored distractor was built and anchored in the first molar and lower canine. It consists of a stainless-steel disjunction screw, adapted and welded to the orthodontic bands through two 1.2 mm diameter connector bars with a universal silver-based and cadmium-free solder; (3) Results: The distractor described can be a useful tool to correct mandibular retrognathia and is better tolerated by patients, especially in severe cases; (4) Conclusions: The dental-anchored distractor increases the anterior mandibular bone segment without affecting the gonial angle or transverse angulation of the segments and avoids posterior mandibular rotation, overcoming the limitations of conventional surgical treatment.

Total facial nerve injury during mandibular distraction osteogenesis

INTRODUCTION

Over the last 10-15 years, usage of internal mandibular distraction systems has increased in the pediatric population, particularly for craniofacial syndromes. Mandibular distraction osteogenesis (MDO) has been shown to be effective in avoiding tracheostomy or achieving early decannulation in patients with micro-retrognathic mandibles in hemifacial microsomia or Pierre Robin sequence. As the frequency of the application of MDO has increased, so has the awareness and management of subsequent complications from the procedure. In this study, we discuss a complication involving paresis and eventual recovery of cranial nerve (CN) VII after the application of an MDO internal device at our institution in two cases. We also review the literature and propose multiple anatomic considerations that can impact more than just the marginal branch of CN VII.

METHOD

This study is a retrospective case study from our institution and a review of the literature. Pubmed was queried for terms singularly and in combination including "mandibular distraction osteogenesis", "facial nerve", "cranial nerve", "complications", "micrognathia", "retrognathia". After reviewing the results, studies discussing complications of MDO that involved CN VII were reviewed and included.

RESULTS

In the literature review and our retrospective review, CN VII injuries from MDO vary in their length and timing of onset. Management of this complication depended on the timing of onset and ranged from conservative management to removal of the distraction device. Majority (7/9) of the cases resolved to an eventual House-Brackmann of 0/6 with conservative measures.

CONCLUSION

Total facial nerve injury in association with MDO, has been scarcely reported, though the facial nerve is at great risk given its intimate location near the mandible particularly in neonates. It is encouraging that though it could be a devastating complication, out of all the cases reported, the large majority resolve with a combination of time and steroids.

Distraction Osteogenesis for Management of Severe OSA in Pierre Robin Sequence: An Approach to Elude Tracheostomy in Infants

BACKGROUND

Severe obstructive sleep apnoea (OSA) is a life threatening condition associated with Pierre Robin sequence (PRS) due to mandibular micrognathia and glossoptosis. Often these patients require tracheostomy at an early age which has high morbidity. Distraction osteogenesis (DO) is an accepted method of treatment for patients with hypoplastic mandible to achieve mandibular lengthening without need for a bone graft. It has also been used in respiratory distressed neonates and infants to avoid tracheostomy.

CASE REPORT

An eight month old baby, a diagnosed case of PRS with severe OSA and recurrent episodes of aspiration pneumonia and on nasogastric tube feeding since birth was referred to us for evaluation and possibility of therapeutic augmentation of the mandible by DO. After a thorough clinico-radiological assessment the child was operated for bilateral extraoral placement of horizontal corpus distractor. A total distraction of 12 mm was carried out and consolidation of callus was monitored by USG. Postoperatively the patient was followed up for 12 months. Presently she has normal respiratory and feeding function without any episode of aspiration pneumonia.

CONCLUSION

Mandibular corpus DO is a safe and effective technique that can be applied to predictably relieve severe upper airway obstruction in selected PRS cases. In order to avoid the limitations of alternative surgical procedures and the tracheostomy-associated morbidity, DO should be considered among the routine treatment modalities.

Facial nerve paralysis and frey syndrome in an infant following removal of an internal mandibular distraction device

Mandibular distraction using an implantable device has become a widely accepted and utilized procedure for the treatment of retrognathia. Although excellent results have been reported and observed with distraction osteogenesis, complications such as facial nerve injury have been previously reported. Often, this injury is usually temporary and corrects over the course of time. Frey syndrome has been classically described as an injury or severance of the auricotemporal branch of the trigeminal nerve. It is commonly seen as a complication of parotid surgery and has never been reported in association with mandibular distraction. The authors report a unique case of both facial nerve paralysis and Frey syndrome in a patient following the removal of an internal mandibular distraction device. A review of the literature along with diagnosis and management are discussed.

Bilateral mandibular distraction osteogenesis in the neonate with pierre robin sequence and airway obstruction: a primary option

Children with craniofacial abnormalities associated with retromicrognathia and glossoptosis often have compromised upper airway flow. In severe cases, emergency intubation is necessary immediately after birth, and tracheostomy is advocated to manage the airway in the neonatal period and to allow for feeding. Early intervention with bilateral mandibular osteogenesis avoids the need for tracheostomy, along with its complications, and it targets the primary etiologic factor of the problem-the anomalous anatomy of the mandible. We report two neonates with severe Pierre Robin sequence managed with bilateral mandibular distraction osteogenesis on day 9 and day 11 of life. The surgical techniques and distraction and consolidation periods were similar apart from the distraction devices used. The procedures were successful with early extubation (day 5 and day 7), oral feeding tolerance (day 11 and day 13) and hospital discharge (day 19 and day 18). Total mandibular distraction was 19 mm and 23.45 mm, respectively. No major complications were reported. Medium to long-term results were good. Bilateral mandibular distraction osteogenesis in the neonate is a safe and accurate procedure and is the primary option in cases of selected severe Pierre Robin sequence.

[Surgical treatment of sleep-related breathing disorders in children]

The surgical treatment of sleep-related breathing disorders in children depends on the cause of the upper airway obstruction, which can be located in the nasal fossae, pharynx (the most frequent adenotonsillar hyperplasia), or larynx (laryngomalacia, cysts…), or can be multilevel, as in syndromic diseases. Adenotonsillectomy is the most frequently performed and effective (70-80%) procedure. The aim of this technique is to normalize nocturnal respiratory parameters and daytime symptoms, as well as to revert, or at least to halt, cardiovascular complications, neurocognitive disturbances, growth delay and enuresis, which can develop if treatment is not provided or is delayed. However, despite its effectiveness, adenotonsillectomy more frequently leads to complications in children with sleep apnea-hypopnea syndrome (SAHS) than in those undergoing this procedure for other reasons. Moreover, 20-30% of children with SAHS who undergo adenotonsillectomy will show residual SAHS, and this percentage can increase to 70% in patients with severe SAHS, Down syndrome, craniofacial anomalies, neuromuscular disturbances, and morbid obesity. Consequently, both clinical and polysomnographic follow-up are recommended after adenotonsillectomy, especially in the latter risk group. Finally, other obstructive disorders of the upper airway must also be treated, although less frequently due to their lower incidence. These disorders include choanal atresia or stenosis, laryngomalacia, and hypoplasia of the midface or mandible. Tracheotomy will sometimes be required.

Chromosome 4q Deletion Syndrome: Craniofacial Characteristics Associated with Monosomy of the Long Arm of Chromosome 4q

Chromosome 4q deletion syndrome is a monosomy that comprises all interstitial and terminal deletions of the long arm of chromosome 4. It results in a variety of phenotypes characterized by various craniofacial and bodily abnormalities. The purpose of this study is to report a case of 4q deletion syndrome and describe its clinical manifestations, with particular attention to the craniofacial presentation and subsequent management of the syndrome, as well as its associated micrognathia and airway complications. Among treatment options, the investigators chose bilateral distraction osteogenesis of the mandible in order to increase the subject's posterior airway space. At follow-up, the subject was able to ventilate without any adjuncts or mechanical ventilation assistance.

Distraction osteogenesis of the mandible for airway obstruction in children: Long-term results

Objective: To determine the long-term results of distraction osteogenesis of the mandible for upper airway obstruction in children with micrognathia.

Study Design: Case series with chart review.

Setting: Tertiary care children's hospital.

Subjects and Methods: The records of a pediatric otolaryngology practice and tertiary children's hospital were searched for patients treated with bilateral mandibular distraction osteogenesis for upper airway obstruction. Patients were selected if greater than three years of follow-up data were available. Data were analyzed for airway and feeding outcomes, and long-term surgical complications were identified.

Results: Thirty-two patients met study criteria. Of the 11 patients who had tracheotomy prior to distraction, seven were decannulated after the procedure. Seventeen patients needed perioperative gastrostomy. Seven are now able to feed orally. Fifteen patients treated with mandibular distraction were able to avoid gastrostomy tube placement altogether. The complication of open bite deformity was experienced by nine patients (28%). Five of 32 patients (16%) had tooth malformation, tooth loss, or dentigerous cyst formation while an additional three patients (9%) had long-term facial nerve injury. Nineteen patients (59%) were under three months old at the time of their distraction. Only one of these patients (5.2%) required an additional distraction procedure.

Conclusion: Long-term follow-up data on patients treated with mandibular distraction for upper airway obstruction show sustained airway improvement. Additionally, micrognathic children treated with distraction have improved outcomes in oral feeding with a relatively low rate of long-term complications. It remains important to follow these patients to monitor the need for secondary reconstructive procedures.

CT analysis after distraction osteogenesis in Pierre Robin Sequence

OBJECTIVES/HYPOTHESIS

Early mandibular lengthening by distraction osteogenesis provides an alternative to traditional methods of airway management in infants with Pierre Robin sequence (PRS). Little evidence in the medical literature quantitatively demonstrates the changes in skeletal, soft tissue, and hypopharyngeal spaces with mandibular distraction.

STUDY DESIGN

Prospective analysis of a cohort of three patients with PRS.

METHODS

We reviewed a series of infants with PRS and severe upper airway obstruction who underwent mandibular distraction. The infants underwent mandibular lengthening with the same internal, unidirectional distraction osteogenesis device. Standardized serial computed tomography (CT) scans were obtained according to established protocol. Computed tomography data were extracted and analyzed with medical image analysis software for mandibulo-maxillary arch harmony, symmetry, hypopharyngeal airway volume, geniohyoid distance, distraction osteogenesis bone volume, and mandibular length.

RESULTS

Mandibulo-maxillary alveolar ridge distances were corrected to 0.5 mm after distraction. Clinical examination showed good arch harmony without open-bite or cross-bite deformities. Mandibular ramus was lengthened by 19.5%; the body, 43.4%. After distraction, total mandibular length was increased by 26.2%; hypopharyngeal airway volume, 192%; posterior distance from pharyngeal wall to tongue base, 198.9%; and geniohyoid distance, 14.1%.

CONCLUSIONS

Unidirectional internal microdistractors can achieve good mandibulo-maxillary arch harmony. Hypopharyngeal airway volume increases substantially, with an even greater increase in distance between tongue base and posterior pharyngeal wall. As the distal mandibular segment is distracted, the hyoid moves anteriorly, with minor increase in geniohyoid relationship. Internal mandibular microdistraction devices represent a substantial advance in airway obstruction management in infants with micrognathia.