Jocelyn M. Shand

A comparison of the stability of single-piece and segmental Le Fort I maxillary advancements.

This study retrospectively evaluated the stability of Le Fort I maxillary advancements and compared segmental and one-piece maxillary osteotomy procedures. A cephalometric analysis was performed on 26 cases of maxillary advancement. The sample comprised 11 cases of one-piece and 15 cases of segmental maxillary procedures. The tracings were superimposed and digitized by computer software, and the skeletal changes were analyzed before surgery, immediately after surgery, and at a minimum of 1 year of follow-up. Different values were compared by the paired and nonpaired t tests and were correlated by the Pearson correlation test. The significant value was set at a 95% confidence interval. The maxilla was advanced by a mean of 5.0 ± 1.6 mm (P < 0.001), and the anterior maxilla was repositioned inferiorly by a mean of 1.5 ± 3.3 mm (P < 0.05). The maxilla relapsed posteriorly by a mean of 0.6 ± 1.2 mm (P < 0.05) and superiorly at the anterior maxilla by a mean of 0.8 ± 1.1 mm (P < 0.001). Overjet and overbite did not significantly change (P > 0.05). It was concluded that maxillary advancement using rigid fixation and interpositional bone grafting in both groups was a stable procedure, particularly in the horizontal plane. In the one-piece group, there was a significantly higher relapse in the vertical plane than in the segmental group (P < 0.05), however. Minor skeletal relapse was compensated for by postoperative tooth movement, and segmental procedures are recommended when required to enhance occlusal results.

Postoperative Anti-Tgf-β2 Antibody Therapy Improves Intracranial Volume and Craniofacial Growth in Craniosynostotic Rabbits

Postoperative resynostosis and secondary craniofacial growth abnormalities are common sequelae after craniofacial surgery. It has been suggested that an overexpression of transforming growth factor-&bgr;2 (Tgf-&bgr;2) may be related to craniosynostosis and contribute to postoperative resynostosis. Interference with Tgf-&bgr;2 function using neutralizing antibodies may inhibit resynostosis and improve postoperative craniofacial growth; the present study was designed to test this hypothesis. Twenty-nine New Zealand white rabbits with bilateral coronal suture synostosis were used: 1) suturectomy controls (n = 9); 2) suturectomy with nonspecific, control IgG antibody (n = 9); and 3) suturectomy with anti-Tgf-&bgr;2 antibody (n = 11). At 10 days of age, a 3 mm × 15-mm coronal suturectomy was performed. The sites in groups 2 and 3 were immediately filled with 0.1 cc of a slow resorbing collagen gel mixed with either IgG (100 &mgr;g/suture) or anti-Tgf-&bgr;2 (100 &mgr;g/suture). Three-dimensional computed tomography scan reconstructions of the skulls and cephalographs were obtained at 10, 25, 42, and 84 days of age. Computed tomography scan data revealed patent suturectomy sites and significantly (P < 0.05) greater intracranial volumes by 84 days of age in rabbits treated with anti-Tgf-&bgr;2 compared with controls. Cephalometric analysis revealed significant (P < 0.05) differences in craniofacial, cranial vault, and cranial base growth by 84 days of age in rabbits treated with anti-Tgf-&bgr;2 compared with controls. These data support the initial hypothesis that interference with Tgf-&bgr;2 function inhibited postoperative resynostosis and improved cranial vault growth in this rabbit model. Thus, this biologically based therapy may be a potential surgical adjunct in the treatment of infants with craniosynostosis.

The role of distraction osteogenesis in the management of craniofacial syndromes

Distraction osteogenesis (DO) has been established as a useful technique in the correction of skeletal anomalies of the long bones for several decades. However, the use of DO in the management of craniofacial deformities has been evolving over the past 20 years, with initial experience in the mandible, followed by the mid-face and subsequently, the cranium. This review aims to provide an overview of the current role of DO in the treatment of patients with craniofacial anomalies.

Skeletal stability of maxillary advancement with and without a mandibular reduction in the cleft lip and palate patient

The stability of surgical maxillary advancement in a consecutive series of patients with cleft lip and palate who underwent Le Fort I osteotomy with and without simultaneous mandibular setback surgery was evaluated. Preoperative, postoperative, and follow-up lateral cephalograms of 21 patients were assessed to compare differences in surgical movement and postoperative relapse between two groups: those who underwent maxillary surgery alone and those who underwent bimaxillary surgery. Differences in the number of patients who experienced relapse of <2mm, 2-4mm, and >4mm between the groups were also compared. Mean advancement of the cleft maxilla was 5.5mm in the maxilla only group and 3.6mm in the bimaxillary group, with a mean horizontal relapse of 0.8mm and 0.2mm, respectively. Mean surgical movement in the vertical dimension was comparable in the two groups and the magnitude of vertical relapse was less than 0.4mm overall. Approximately 80% of patients in both groups experienced horizontal relapse of less than 2mm. There was no significant difference in the degree of postoperative relapse between those who had single-jaw surgery and those who had two-jaw surgery.

Odontogenic myxoma in the paediatric patient: a review of eight cases

Paediatric odontogenic myxoma (OM) is a rare pathological condition in the oral and maxillofacial region. There has been much debate in the literature regarding the preferred method of treatment; however due to the rare nature of this disease, definitive algorithms of management are yet to be determined. A case series of eight paediatric patients with OM is presented. Six of the lesions were in the maxilla and two were mandibular lesions. The patients were aged between 2 and 18 years. Treatment ranged from excision and the application of Carnoys solution to segmental resection and reconstruction. From this case series it can be seen that even in situations where treatment was limited to excision and the application of Carnoys solution, no recurrences occurred. As such the present authors favour an initially more conservative approach to the management of these lesions where possible and reserving conventional resective treatment for recurrences, lesions causing pathological fracture, and those in regions that are difficult to access.

Secondary bone grafting of alveolar clefts: a review of outcome at two centres in Australia and the UK

Secondary alveolar bone grafting is a key procedure in comprehensive cleft services, the main objective of which is to allow the canine to erupt through the bone. We have assessed the outcomes of the procedure at two units, one in Australia and one in the UK. Success was measured using standardised indexes for radiological assessment (Bergland and Kindelan) and clinically by noting eruption of canines through the grafted sites. The two-year review indicated that the two units had comparably high success rates. Canines erupted through cleft sites in 27/28 sites in patients in the UK, and 26/28 in patients in Australia, and the radiological success using the indexes was also high. These rates are in line with international benchmarks.

Infant Mandibular Distraction for Upper Airway Obstruction: A Clinical Audit

Background: Mandibular distraction osteogenesis (MDO) is an effective method of treating upper airway obstruction (UAO) in micrognathic infants. The short-term outcomes include relief of UAO, avoidance of tracheostomy, and prompt discharge from hospital. However, it is a significant surgical procedure with potential associated morbidities. This study describes a cohort of infants managed using MDO over a twelve-year period. Methods: A retrospective chart review was undertaken for children who had MDO before the age of 5 years between 2000 and 2012. This was followed by a clinical review of the same cohort specifically looking for dental anomalies, nerve injuries, and scar cosmesis. Results: Seventy-three children underwent MDO at a mean age of 2 months [interquartile range (IQR), 1.7–4.2] for nonsyndromic infants and 3.3 months (IQR, 2.1–7.4) for those with syndromes. Infants were discharged from hospital, on average, 15 days after procedure. After MDO, of the 9 who were previously tracheostomy dependent, 5 (56%) were decannulated within 12 months and none of the nontracheostomy-dependent children required further airway assistance. The majority of children required supplemental feeding preoperatively but, 12 months postoperatively, 97% of the nonsyndromic infants fed orally. Thirty-nine children (53%) were reviewed clinically [median age, 5.1 y (IQR, 3.9–6.5)] with 18 being syndromic. Many of the mandibular first permanent and second primary molars had developmental defects, but there was a low rate of neurosensory deficit and good scar cosmesis. Conclusions: This study contributes further to the evidence base underpinning the management of micrognathic infants with UAO.

Rescue of Premature Coronal Suture Fusion With TGF-β2 Neutralizing Antibody in Rabbits With Delayed-Onset Synostosis

Objectives: An overexpression of Tgf-β2 leads to calvarial hyperostosis and suture fusion in individuals with craniosynostosis. Inhibition of Tgf-β2 may help rescue fusing sutures and restore normal growth. The present study was designed to test this hypothesis. Design: Twenty-eight New Zealand White rabbits with delayed-onset coronal synostosis had radiopaque markers placed on either side of the coronal sutures at 10 days of age. The rabbits were randomly assigned to: (1) sham control rabbits (n = 10), (2) rabbits with control IgG (100 μg/suture) delivered in a collagen vehicle (n = 9), and (3) rabbits with Tgf-β2 neutralizing antibody (100 μg/suture) delivered in a collagen vehicle (n = 9). Longitudinal growth data were collected at 10, 25, 42, and 84 days of age. Sutures were harvested at 84 days of age for histomorphometry. Results: Radiographic analysis showed significantly greater (P < .05) coronal suture marker separation, craniofacial length, cranial vault length, height, shape indices, cranial base length, and more lordotic cranial base angles in rabbits treated with anti-Tgf-β2 antibody than in controls at 42 and 84 days of age. Histologically, rabbits treated with anti-Tgf-β2 antibody at 84 days of age had patent and significantly (P < .05) wider coronal sutures and greater sutural area compared to controls. Conclusions: These data support our hypothesis that antagonism of Tgf-β2 may rescue fusing coronal sutures and facilitate craniofacial growth in this rabbit model. These findings also suggest that cytokine therapy may have clinical significance in infants with progressive postgestational craniosynostosis.

Rebuttal to Breugem et al.'s comment on Anesthetic implications of infants with mandibular hypoplasia treated with mandibular distraction osteogenesis

Objectives: To document the incidence of difficult intubation following mandibular distraction osteogenesis (MDO) in children with severe mandibular hypoplasia. Background: Syndromes associated with significant mandibular hypoplasia, especially Pierre Robin sequence, provide a challenge in airway management both in and out of the operating room. Mandibular advancement using mandibular distraction osteogenesis devices has been used in infants in an attempt to reduce the incidence of acute life-threatening airway obstruction. Whether MDO also reduces the incidence of difficult intubation has not been adequately described. Methods: A retrospective chart review of 51 infants with upper airway obstruction secondary to mandibular hypoplasia who required MDO between January 2002 and 2012. The primary outcome was the incidence of difficult or failed intubation. Secondary outcomes were the relationship between syndrome type and the incidence of difficult intubation. Results: Fifty-one PRS infants were identified. Twenty-eight patients had isolated PRS, six had syndromic PRS, seven had Treacher Collins syndrome, and 10 had another coexisting syndrome. Prior to mandibular distraction osteogenesis (MDO), the incidence of difficult intubation was 71%, with the highest incidence in patients with Treacher Collins syndrome (100%), sPRS syndrome (100%), and PRS (65%). Following MDO, the incidence of difficult intubation was 8.3%. The difference was statistically significant for all patients (Kruskal–Wallis rank test P = 0.0001) those with isolated PRS (P = 0.0001), syndromic PRS (P = 0.0023), and other syndromes (P = 0.0002), but not for Treacher Collins syndrome (P = 0.21). Three patients had pre existing tracheostomies. Conclusions: In a select group of infants with severe upper airway obstruction who have failed nonsurgical airway interventions, mandibular distraction osteogenesis reduces the incidence of difficult mask ventilation and difficult intubation. We were not able to compare the improvement in airway management to a comparable group of PRS infants who did not undergo surgical intervention. The improvement in laryngeal view was most marked for infants with isolated PRS but no significant benefit was demonstrated in infants with TCS.