Monobloc Distraction Research Articles

Long-Term Orbito-ocular Outcomes Following LeFort III and Monobloc Distraction Osteogenesis in Patients with Syndromic Craniosynostosis.

Exorbitism in patients with syndromic craniosynostosis is often managed by LeFort III (LF3) or Monobloc (MB) distraction osteogenesis (DO). This study compared short- and long-term orbital craniometrics after LF3DO/MBDO and related these findings to symptom relief. Patients undergoing LF3DO or MBDO from 2000-2021 with pre- and postoperative imaging were included. Postoperative CTs were categorized as early (<1 year) or late (>1 year), and age-matched control CTs were compared to late postoperative scans. Superior/inferior orbital rim position, relative globe position, and orbital volume were analyzed. Symptoms were assessed by a patient-reported outcome (PRO) analysis. Thirty-four patients (16 LF3DO, 18 MBDO) were matched by age at surgery, sex, syndrome, and age at imaging. Time to late CT was 6.2 years (LF3DO) and 7.5 years (MBDO). Between early and late postoperative time points, LF3DO patients experienced no change in inferior rim position. MBDO patients experienced a decrease in inferior orbital rim position of 4.7mm (p=0.005), but superior orbital rim distance remained stable. Comparison of late scans and age-matched controls revealed no difference in inferior or superior orbital rim position in LF3DO patients, but the superior orbital rim distance was longer in MBDO patients (p=0.015). PRO response rate was 76% with a median follow up of 13.7 years. Most (81%) symptomatic patients improved, 19% remained symptomatic, and no patients worsened. LF3DO and MBDO achieved stable orbital craniometric changes, with improved stability at the inferior orbital rim after LF3DO. Craniometric changes were associated with long-term exorbitism symptom relief.

An Unoperated Crouzon Family Treated with Monobloc Distraction: Challenges and Lessons.

Background:Crouzon syndrome (CS) is a rare form of craniosynostosis characterized by bicoronal craniosynostosis and facial features including severe midface hypoplasia, exophthalmos, and hypertelorism. Most patients are diagnosed and treated in early childhood; however, there are a few reports of Crouzon patients treated as adults with monobloc facial advancement. To our knowledge, this is the first report of a family affected by CS treated sequentially with monobloc facial advancement using combined internal and external distraction osteogenesis (rigid external distraction).Methods:We present a family from Jamaica (mother 47 years old, older daughter 17, and younger daughter 9) who were brought to our craniofacial clinic with stigmata of CS and no previous surgical intervention. Patients had bicoronal craniosynostosis and exorbitism, with varying severity, sequelae, and comorbidities. Here, we delineate our technique of monobloc distraction osteogenesis with advancement osteotomies using dual “push–pull” method, elevation of a split anteriorly based tunneled pericranial flap to seal off nasal cavity, and internal and external distraction.Results:Our patients had favorable outcomes after reconstruction to reduce ocular symptoms and improve midface hypoplasia and aesthetic appearance. No intracranial injury, hardware/soft-tissue infection, hardware failure, or (new) loss of vision were encountered in 10 months follow-up.Conclusions:Dual “push–pull” monobloc distraction is safe and effective for a range of ages in CS; it allows good vector control, accommodates patient compliance, and allows early rigid external distraction device removal with sufficient time for consolidation. This surgery can be performed with highly satisfactory results.

Monobloc Facial Advancement in the World of COVID-19 Testing: A New Potential Risk for Iatrogenic Injury

Background: Monobloc advancement with distraction is a holistic approach to treat the sequelae of syndromic craniosynostosis. These osteotomies create a communication between the nasal cavity and anterior cranial fossa that must be surgically obliterated to limit the infectious risks. In light of mandatory COVID-19 testing protocols amidst the pandemic, we aim to identify the specific challenges in management and present our strategy to overcome them. Case presentation: We report 2 cases of syndromic craniosynostosis treated with monobloc distraction during the COVID-19 pandemic and highlight safety concerns and our approach to managing these patients by avoiding nasopharyngeal swabs that may potentially penetrate the cranial base and place the patient as risk for iatrogenic injury. Discussion/conclusion: In patients undergoing surgical procedures that create a cranial base defect, caution must be exercised when attempting to test for COVID-19 which may be a source of potential iatrogenic injury. We propose a new algorithm for COVID-19 screening/surveillance following frontofacial advancement. Patients must be screened via alternative testing methods or treated as potential asymptomatic carriers of COVID-19 until postoperative imaging demonstrates complete ossification of the cranial base.

Midface Morphology and Growth in Syndromic Craniosynostosis Patients Following Frontofacial Monobloc Distraction.

Facial advancement represents the essence of the surgical treatment of syndromic craniosynostosis. Frontofacial monobloc distraction is an effective surgical approach to correct midface retrusion although someone consider it very hazardous procedure. The authors evaluated a group of patients who underwent frontofacial monobloc distraction with the aim to identify the advancement results performed in immature skeletal regarding the midface morphologic characteristics and its effects on growth. Sixteen patients who underwent frontofacial monobloc distraction with pre- and postsurgical computed tomography (CT) scans were evaluated and compared to a control group of 9 nonsyndromic children with CT scans at 1-year intervals during craniofacial growth. Three-dimensional measurements and superimposition of the CT scans were used to evaluate midface morphologic features and longitudinal changes during the craniofacial growth and following the advancement. Presurgical growth was evaluated in 4 patients and postsurgical growth was evaluated in 9 patients. Syndromic maxillary width and length were reduced and the most obtuse facial angles showed a lack in forward projection of the central portion in these patients. Three-dimensional distances and images superimposition demonstrated the age did not influence the course of abnormal midface growth. The syndromic midface is hypoplastic and the sagittal deficiency is associated to axial facial concavity. The advancement performed in mixed dentition stages allowed the normalization of facial position comparable to nonsyndromic group. However, the procedure was not able to change the abnormal midface architecture and craniofacial growth.

Analysis of complications following multidisciplinary functional intervention in paediatric craniomaxillofacial deformities

Paediatric craniomaxillofacial (CMF) surgery requires a multidisciplinary team approach to ensure the optimal and holistic management of children with craniofacial deformities. The aim of this retrospective study was to analyse the complications following functional interventions among 34 CMF deformity patients in a single multidisciplinary craniofacial centre. Electronic data including patient demographic characteristics and clinical entry were analysed. Inclusion criteria were all paediatric patients with CMF deformities who underwent various functional interventions. A total of 64 interventions (48 intermediate and 16 definitive) were conducted. Based on the Sharma classification of complications, 20.3% were type I, 4.7% were type II, 1.6% were type III, and 4.7% were type IV . Most complications were type I, which included local infection (3.1%) and premature opening of tarsorrhaphy (3.1%). More serious complications (types III and IV) included temporary visual loss (1.6%) and intraoperative haemorrhage (1.6%). Although a low complication rate was observed in intermediate interventions, a higher complication rate was observed in more complex definitive interventions such as monobloc distraction osteogenesis. Although most complications were manageable, effective prevention remains mandatory, as serious complications may lead to permanent damage and mortality. This analysis highlights the importance of a multidisciplinary team approach to optimize the outcomes in CMF patient management.

The Monobloc Distraction With Facial Bipartition: Outcomes of Simultaneous Multidimensional Facial Movement Compared With Monobloc Distraction or Facial Bipartition Alone.

Although combined monobloc facial bipartition with distraction (MFBD) may simultaneously correct multiple facial dimensions in patients with syndromic craniosynostoses, complication risks limit its use. This study reassesses MFBD complications and outcomes to compare safety and efficacy to monobloc distraction (MD) and facial bipartition (FB) alone. A retrospective review of MFBD, MD, and FB cases for 10 years at a tertiary children's hospital was performed. Patient demographics and surgical variables were compared between cohorts. Distraction distance was compared between MFBD and MD. Correction of interdacryon distance in MFBD compared with FB was measured on preoperative and postoperative computed tomographic scans. SPSS 17 was used for data analysis. Twenty-two total patients, 11 MFBD, 4 MD, and 7 FB, met the inclusion criteria. Three MFBD (27.3%) patients experienced complications, including 1 osteomyelitis and 2 hardware displacements. One MD patient (25%) experienced a postoperative complication consisting of a wound infection. Three FB patients (42.9%) experienced either cerebrospinal fluid leak, seroma, mucocele, hardware exposure, and/or orbital dystopia (n = 1 each). Patients with MFBD had significantly longer intensive care unit stay (P ≤ 0.05), but no difference in hospital stay (P = 0.421). Mean distraction length was similar between MFBD and MD (P = 0.612). There was no significant difference in final (P = 0.243) or change (P = 0.189) in interdacryon distance between MFBD and FB patients. In our experience, MFBD has similar complication rates compared with MD and FB alone. Given equivalent safety and postoperative correction of facial dimensions, MFBD could be more widely considered for select patients.

Outcomes of Intracranial Versus Subcranial Approaches to the Frontofacial Skeleton

An intracranial approach to the craniomaxillofacial skeleton can be effective for correcting complex craniofacial dystoses such as frontofacial hypoplasia, hypertelorism, and orbital dystopia. However, the significant morbidity resulting from the high complication rates has limited intracranial use. Given the need for intracranial approaches for certain clinical indications, the present study reevaluated intracranial frontofacial procedures to determine their safety and outcomes. A retrospective review was performed of all frontofacial procedures completed between 2007 and 2017 at a single institution. Patients who had undergone monobloc distraction alone or with facial bipartition, facial bipartition alone, or box osteotomy were included in the intracranial cohort. Those who had undergone Le Fort III distraction, advancement, or a combination with Le Fort I were included in the subcranial cohort. The recorded data included demographics, previous craniofacial surgery, and operative events. The complications rates were compared between the 2 cohorts. The present study included 65 patients-35 subcranial and 30 intracranial. The rates of previous craniomaxillofacial (P=.193) and intracranial (P=.340) surgery were equivalent between the 2 cohorts. Of the 30 intracranial and 35 subcranial patients, 26.7% and 34.3% experienced complications (P=.218). The intracranial patients experienced more dural tears (53.3 vs 5.7%; P<.0001); however, no significant differences were observed in cerebrospinal fluid leakage. Reintubations (n=3; 4.5%) occurred exclusively in the subcranial group. No significant differences in the major and minor complication rates were observed between the 2 cohorts. Intracranial and subcranial frontofacial procedures are associated with an equal riskof major and minor complications. Given the lack of an increase in risk, intracranial frontofacial procedures should be considered for the management of complex craniofacial dystoses.

S12-17 SESSION 12: FACIOCRANIOSYNOSTOSIS – PART II PAN-FACIAL DISTRACTION FOR SEVERE CRANIO-MAXILLOFACIAL RETRUSION:

Introduction: Monobloc distraction can effectively improve patients with severe cranio-maxillofacial retrusion suffering from increased intra-cranial pressure, orbital proptosis and obstructive sleep apnea. In these patients, their mandibles may look normal or even protrusive. However, at the end of the monobloc distraction advancement, their mandibles commonly become retrusive when compared with the forwarded distracted midface. Their obstructive sleep apnea might not improve as the retro-lingual airway becomes the bottle-neck. The aim of the presentation is to present a new concept of pan-facial distraction for cranio-synostosis children suffering from severe cranio-maxillofacial retrusion. Methods: Children with typical midfacial depression, orbital proptosis and increased intra-cranial pressure having confirmed cranio-synostosis will go through a full upper airway assessment by a combination of CT scan, computerized airway measurement and sleep endoscopic evaluation. The upper airway at different levels (naso-pharyngeal, uvula, base of tongue, larynx) were measured in transverse and antero-posterior planes as well as Volumatic measurement of airway volume. When the upper airway at the nasopharynx, retro-uvula and retro-lingual dimensions were restricted, pan-facial distraction by means of simultaneous mono-bloc and mandibular distraction was performed with a combination of external and internal distractors. Results: Clinical cases will be presented to illustrate the clinical improvement that can be achieved when this concept was implemented in children with syndromal craniosynostosis. Conclusion: Pan-facial distraction is effective in alleviating the obstructive sleep apnea syndrome of children with syndromal craniosynostosis suffering from multiple levels of airway obstruction.

S12-12 SESSION 12: FACIOCRANIOSYNOSTOSIS – PART II MONOBLOC MINUS LEFORT II: THE ROLE OF DIFFERENTIAL DISTRACTION FOR TREATMENT OF THE APERTS CRANIOFACIAL PHENOTYPE

Introduction: Apert patients often require differential advancement of the forehead, orbits, and midface to correct fronto-orbital retrusion, lengthen the midface and nose, and close the anterior open bite. While traditionally done in stages, the Monobloc + Le Fort II distraction addresses these differential movements in a single operation. Advancement of the forehead and midface is accomplished with the monobloc, while the nose and central midface is inferiorly advanced and rotated using the Le Fort II distraction. The purpose of this study is to evaluate the skeletal 3D cephalometric changes utilizing this technique in the management of Aperts syndrome. Methods: A retrospective review was performed of the senior surgeons experience utilizing this technique in patients with Aperts syndrome. Pre and post distraction 3D CT cephalometrics were analyzed and compared to a historical published cohort of Aperts patients. Vertical and axial facial ratios were calculated before and after distraction, and these ratios were also compared between cohorts. Results: 3 patients with Aperts syndrome underwent a Monobloc + lefort II differential distraction at an average age of 8 years, and with an average length of follow up of 30 months. The following 3D cephalometric landmarks and angles were measured: Glabella, nasion, incisor midline, ANS, sella, lateral inferior orbit, SNA, SNB, occlusal plane, and maxillary mandibular incisor relationship (see chart). Average Vertical Facial Movements ANS to N: 16.3mm N to Lateral inferior orbit (LIO): 3.81mm; Average Axial Facial Movements and Ratios ANS to Sella: 31.1mm Sella to LIO: 9.05mm Sella to LIO/S to ANS: 0.290 Comparison to historical control in the literature: Lefort II distraction with zygomatic repositioning. Axial facial movement ratio: Sella to LIO/S to ANS Monobloc/Lefort II mean: 0.292 Lefort II/Zygoma Repositioning: 0.276 P = 0.43 (NS) Vertical Facial Movements Ratio: N to LIO/N to ANS Monobloc/Lefort II: 0.241 Lefort II/Zygoma Repositioning: 0.203 Conclusion: Differential distraction with the Monobloc + Lefort II allows for resolution of exorbitism, improvement in negative canthal tilt, lengthening of the nose, and closure of the anterior open bite in patients with Apert syndrome. The increased distraction and rotation of the central midface results in more normal facial ratios that are not observed with traditional monobloc distraction.

Correcting Exorbitism by Monobloc Frontofacial Advancement in Crouzon-Pfeiffer Syndrome: An Age-Specific, Time-Related, Controlled Study.

In FGFR2 craniosynostosis, midfacial hypoplasia features oculo-orbital disproportion and symptomatic exorbitism. Clinical consequences may mandate surgery at a young age to prevent globe subluxation, corneal ulceration, and potential loss of vision. Monobloc osteotomy and distraction osteogenesis (monobloc distraction) seek to correct exorbitism. A report of the age-related impact of monobloc osteotomy and distraction osteogenesis on orbital volume, globe volume, and globe protrusion is presented. Computed tomographic scan data from 28 Crouzon-Pfeiffer patients were assessed at preoperative, early postoperative, and 1-year follow-up time points. Orbital volumes, globe volumes, and globe protrusions were measured by manual and semiautomatic segmentation techniques, and these were compared to 40 age-matched controls. Crouzon-Pfeiffer syndrome orbital volumes are significantly small, and are significantly overexpanded by distraction to endpoints correcting symptomatic exorbitism. Globe volumes are significantly larger than controls under 5 years, do not independently correlate with globe protrusion, and are unaffected by surgery. Correlation between orbital volume expansion and reduction of globe protrusion is not significant. Age-related variations of postoperative growth potential occur to 1 year postoperatively. The Crouzon-Pfeiffer syndrome FGFR2 orbit exhibits early growth acceleration followed by premature growth arrest at 10 to 14 years. Orbital volume expansion by monobloc osteotomy and distraction osteogenesis is not the sole determinant of reduced globe protrusion. Mean volume relapse of the orbit at 1 year is insignificant across the series. Derived Crouzon-Pfeiffer growth curves suggest that "early functional monobloc" in infants occurs on a background of dynamic orbital growth, which remains programmed to a Crouzon-Pfeiffer FGFR2 phenotype and aligns with the incidence of delayed clinical regression and later secondary surgery. Therapeutic, IV.

Use of three-dimensional, CAD/CAM-assisted, virtual surgical simulation and planning in the pediatric craniofacial population

ObjectiveVirtual Surgical Planning (VSP) and computer-aided design/computer-aided manufacturing (CAD/CAM) have recently helped improve efficiency and accuracy in many different craniofacial surgeries. Research has mainly focused on the use in the adult population with the exception of the use for mandibular distractions and cranial vault remodeling in the pediatric population. This study aims to elucidate the role of VSP and CAD/CAM in complex pediatric craniofacial cases by exploring its use in the correction of midface hypoplasia, orbital dystopia, mandibular reconstruction, and posterior cranial vault expansion. Method/DescriptionA retrospective analysis of thirteen patients who underwent 3d, CAD/CAM- assisted preoperative surgical planning between 2012 and 2016 was performed. All CAD/CAM assisted surgical planning was done in conjunction with a third party vendor (either 3D Systems or Materialise). Cutting and positioning guides as well as models were produced based on the virtual plan. Surgeries included free fibula mandible reconstruction (n = 4), lefort I osteotomy and distraction (n = 2), lefort II osteotomy with monobloc distraction (n = 1), expansion of the posterior vault for correction of chiari malformation (n = 3), and secondary orbital and midface reconstruction for facial trauma (n = 3). The patient's age, diagnosis, previous surgeries, length of operating time, complications, and post-surgery satisfaction were determined. ResultsIn all cases we found presurgical planning was helpful to improve accuracy and significantly decrease intra-operative time. In cases where distraction was used, the planned and actual vectors were found to be accurate with excellent clinical outcomes. There were no complications except for one patient who experienced a wound infection post-operatively which did not alter the ultimate reconstruction. All patients experienced high satisfaction with their outcomes and excellent subjective aesthetic results were achieved. ConclusionsPreoperative planning using CAD/CAM and VSP allows for safe and precise craniofacial reconstruction in complex pediatric cases with a reduction of operative time.

Structural and actual distraction discrepancy following monobloc distraction in syndromic craniosynostosis

Structural and actual distraction discrepancy following monobloc distraction in syndromic craniosynostosis

Discussion: Evaluating the Efficacy of Monobloc Distraction in the Crouzon-Pfeiffer Craniofacial Deformity Using Geometric Morphometrics

Discussion: Evaluating the Efficacy of Monobloc Distraction in the Crouzon-Pfeiffer Craniofacial Deformity Using Geometric Morphometrics

Frontofacial advancement by distraction osteogenesis: a long-term review.

Frontofacial advancement by distraction osteogenesis is known to produce significant functional and aesthetic gains in the short and medium term. Little is known about the long-term effects of this technique. The authors present a long-term review of frontofacial advancement by distraction in patients with syndromic craniosynostosis. In 2008, Witherow et al. presented functional outcomes in 20 consecutive patients who underwent frontofacial advancement by distraction osteogenesis using the rigid external distractor frame. This retrospective study has revisited the outcomes in these patients after a mean follow-up period of 10.2 years. Records for the original 20 patients were assessed. Cephalometric analysis demonstrated stable advancements over the long term. No patient achieved any anterior growth of the midface after frontofacial advancement. Long-term follow-up demonstrated a later deterioration of respiratory function in the younger group of patients (36.4 percent). Four patients required adenotonsillectomy. One patient has a persistent tracheostomy. Only one patient required further procedures to correct recurrent raised intracranial pressure. None of the patients in the older group experienced a deterioration of function. Other procedures included reduction of the supraorbital ridge, bimaxillary osteotomies, and rhinoplasties. Frontofacial distraction produced long-term stable advancement in all cases, and 15 of the 17 living patients (88.2 percent) achieved stable functional gains. Anterior growth of the midface does not occur following monobloc distraction. Deterioration in function is seen in those who undergo this procedure at a young age. The authors recommend regular follow-up of these patients. Therapeutic, IV.

Frontoethmoidal Mucocele Following Pediatric Craniofacial Surgery

Mucoceles occur as a result of accumulation and retention of mucous secretions in a paranasal sinus and are uncommon in the pediatric age group. Persistent or intermittent closure of its ostium through a variety of causes, including previous surgery, is implicated in etiology. The authors report 2 cases of frontoethmoidal mucocele that followed box osteotomies for the treatment of orbital dystopia, with medical literature review and discussion of possible causal factors and events. Case histories and radiological imaging are presented on 2 patients presenting with frontoethmoidal mucoceles following craniofacial surgery. Both had transcranial craniofacial techniques where all orbital walls and globe are moved en bloc as a "box." Patient 1, a 12-year-old male patient with Crouzon syndrome, developed mucoceles within 18 months of monobloc distraction surgery and box osteotomies. This was successfully marsupialized with a combined external and endoscopic surgical approach. The second patient, a 15-year-old boy with previously corrected right-sided facial cleft, developed mucocele 9 years following box osteotomies; this was successfully managed by endoscopic drainage. Of 3 other patients having similar box osteotomies in our unit, no other mucoceles were noted as complications. Mucoceles are a rare complication of craniofacial surgery, and literature review confirms a paucity of reports. Only 1 case has previously been alluded to of mucocele complicating box osteotomy for orbital dystopia. Our 2 cases illustrate and highlight a successful management approach in a multidisciplinary craniofacial unit.

Monobloc Minus Le Fort II for Single-Stage Treatment of the Apert Phenotype

Treatment of the Apert syndrome phenotype aims to correct airway obstruction, exorbitism, elevated intracranial pressure, midface hypoplasia, and malocclusion. Cranial vault expansion prevents elevated intracranial pressure, normalizes head shape, and protects the globes, but variation exists in surgical timing and osteotomy to treat the midface. We present the case of an 11-year-old female patient with Apert syndrome and no prior surgical interventions who presented with severe turribrachycephaly, exorbitism, severe midface retrusion, and apertognathia. A monobloc distraction with simultaneous Le Fort II distraction was planned using computer-aided design and modeling (CAD/CAM) techniques to provide for concurrent distraction of the segments in independent vectors without bony interferences. Monobloc minus Le Fort II distraction was performed without intraoperative complications. Surgical time was 340 minutes with an estimated blood loss of 1100 mL. Distraction began on postoperative day 5 at a rate of 1.5 mm/day for the Le Fort II via an external Halo distractor and 1 mm/day for the monobloc segment via internal distractors anchored bitemporally. The monobloc was distracted a total of 17 mm in a horizontal vector, while the Le Fort II segment was distracted 18 mm horizontally and 5 mm inferiorly. The Halo distractor was removed 3 months following the procedure and the internal distractors 1 month later. Monobloc minus Le Fort II distraction enables correction of the Apert phenotype with a single-stage approach, potentially decreasing the burden of care with improved results. Utilization of CAD/CAM modeling allows for accurate planning of multisegment distraction in independent vectors without concerns for bony interferences.

Soft-Tissue Volumetric Changes Following Monobloc Distraction Procedure

We have previously reported that monobloc advancement by distraction osteogenesis resulted in decreased morbidity and greater advancement with less relapse compared with acute monobloc advancement with bone grafting. In this study, we examine the three-dimensional (3D) volumetric soft-tissue changes in monobloc distraction.Patients with syndromic craniosynostosis who underwent monobloc distraction from 2002 to 2010 at University of California-Los Angeles Craniofacial Center were studied (n = 12). We recorded diagnosis, indications for the surgery, and volumetric changes for skeletal and soft-tissue midface structures (preoperative/postoperative [6 weeks]/follow-up [>1 year]). Computed tomography scans and a digital 3D photogrammetry system were used for image analysis.Patients ranged from 6 to 14 years of age (mean, 10.1 years) at the time of the operation (follow-up 2-11 years); mean distraction advancement was 19.4 mm (range, 14-25 mm). There was a mean increase in the 3D volumetric soft-tissue changes: 99.5 ± 4.0 cm(3) (P < 0.05) at 6 weeks and 94.9 ± 3.6 cm(3) (P < 0.05) at 1-year follow-up. When comparing soft-tissue changes at 6 weeks postoperative to 1-year follow-up, there were minimal relapse changes. The overall mean 3D skeletal change was 108.9 ± 4.2 cm. For every 1 cm of skeletal gain, there was 0.78 cm(3) of soft-tissue gain.Monobloc advancement by distraction osteogenesis using internal devices resulted in increased volumetric soft-tissue changes, which remained stable at 1 year. The positive linear correlation between soft-tissue increments and bony advancement can be incorporated during the planning of osteotomies to achieve optimum surgical outcomes with monobloc distraction.

Correcting the Typical Apert Face

Bipartition distraction is a novel procedure combining frontofacial bipartition and monobloc distraction. Apert syndrome and other syndromic craniofacial dysostoses are often characterized by hypertelorism, with a negative canthal axis and counterrotated orbits. Central midface hypoplasia can result in a biconcave face in both midsagittal and axial planes. Bipartition distraction can correct these facial abnormalities. Twenty patients (19 Apert syndrome patients and one Pfeiffer syndrome patient, aged 1.6 to 21 years) underwent bipartition distraction. Severity of appearance was graded preoperatively and postoperatively as mild, moderate, or severe. Functional problems were documented by a multidisciplinary team. Central and lateral midface skeletal advancement were measured. Follow-up ranged from 15 months to 7 years. Bipartition distraction consistently produced more central than lateral facial advancement. Mean central advancement was 13.2 ± 5.9 mm at sella-nasion and 11.7 ± 5.4 mm at sella-A point. Lateral advancement was 4.7 ± 2.8 mm. Unbending the face improved aesthetic appearance. Airway function, eye exposure, and elevated intracranial pressure were improved. Complications included six temporary cerebrospinal fluid leaks (four needing a lumbar drain), five patients with postoperative seizures, five patients requiring Rigid External Distraction frame repositioning, one palatal fistula, one velopharyngeal incompetence, five pin-site infections, one abscess under frontal bone, three cases of sepsis, nine patients with worsened strabismus, two patients with enophthalmos, one patient with partial visual field loss, and three patients who required reintubation because of aspiration. : Bipartition distraction is an effective procedure with which to differentially advance the central face in Apert syndrome. It improves both function and aesthetics. : Therapeutic, IV.

Orbital aspects following monobloc advancement in syndromic craniosynostosis

The monobloc advancement with distraction is a treatment modality for syndromic craniosynostosis, to correct exorbitism, upper airway compromise and malocclusion. In this report orbital volume and movements of (peri-)orbital structures and globes of seven patients following monobloc distraction are evaluated. In preoperative and postoperative CT-scans orbital volume was assessed and a 3D coordinate system with eleven landmarks was used to measure the movements of orbital structures and globes and to measure the change of exorbitism. Correlation between orbital volume, movements of the orbital structures and change in exorbitism was studied. The orbital volume increased by 49.9% (left) and 50.4% (right). The average anterior movement of the bone was 13.6 mm (left) and 13.9 mm (right). The mean anterior movement of the left globe was 5.8 mm and of the right globe 5.3 mm. The ratio of globe/bone movement was 0.4. Exorbitism decreased with 7.8 mm (left) and 8.1 mm (right). Differences between left and right for orbital volume, for movements and for the decrease in exorbitism were not significant. Volume enlargement and decrease in exorbitism were correlated (p ≤ 0.05). Following monobloc advancement orbital volume increases, (peri-)orbital structures and the globe move forward and exorbitism diminishes.

Vector Control in Internal Midface Distraction Using Temporary Anchorage Devices

Le Fort III and monobloc distraction osteogenesis serve as the primary surgical treatment for children with severe midface hypoplasia. The orbital retrusion and class III malocclusion of patients with midface hypoplasia is best addressed with bodily advancement of the midface segment parallel to the cephalometric Frankfort horizontal plane. Use of internal distraction devices allows for advancement of the midface without extensive external hardware but comes at the cost of less vectorial control, resulting in a distraction vector that can cause a clockwise rotation of the entire midface or frontofacial component creating hollow appearing orbits. To counteract this clockwise rotation, we have developed a technique using orthodontic microimplants to anchor interarch class III relationship elastics. We report our experiences with this technique on a cadaveric model and as a case series of 17 patients who underwent midface distraction. A Le Fort III distraction procedure was carried out on a cadaver, and the orbital height was measured at 0-, 10-, and 20-mm distraction advancement with and without elastics in a class III relationship. Improvement of both subjective hollow appearance of the orbits and objective measurement of the orbital height with class III relationship elastics demonstrated the efficacy of class III relationship elastics in counteracting the clockwise rotation of the midface segment. A review of 17 patients with midface or frontofacial hypoplasia treated with Le Fort III or monobloc distraction with simultaneous microimplant anchored class III relationship elastics revealed correction of malocclusion and improved midface projection without significant increase in vertical height of the orbits.