Internal Distraction Osteogenesis Research Articles

Computer-Assisted Frontofacial Monobloc Advancement and Facial Bipartition for Pfeiffer Syndrome: Surgical Technique

In patients with Pfeiffer syndrome, several corrections are required to correct facial retrusion, maxillary deficiency, or even hypertelorism. The frontofacial monobloc advancement (FFMA) and the facial bipartition (FB) are the gold standard surgeries. We present the correction of this deformity using a simultaneous computer-assisted FFMA and FB. The 3-dimensional surgical planning defined the virtual correction and bone-cutting guide in view of the FFMA and FB. Coronal and intraoral approaches were combined to perform the osteotomies. Four internal distractors were also placed for the postoperative distraction osteogenesis. We reported 2 cases of computer-assisted surgery with satisfying outcomes. The sagittal deficiency (fronto-facial retrusion) was corrected by FFMA and the transversal abnormality (i.e., hypertelorism and maxillary deficiency) by the FB, then followed by an internal distraction osteogenesis. Computer-assisted surgery is helpful and a reliable option for the management of complex faciocraniosynostosis such as hypertelorism and frontofacial retrusion.

Does the Rigid External Distraction Device Alter Maxillary Pitch in Cleft Maxillary Distraction?

Statement of problemCorrection of cleft maxillary hypoplasia remains a controversial topic. Surgical correction can be accomplished through Le Fort I orthognathic correction, internal distraction osteogenesis, or external distraction osteogenesis.1 Proponents of rigid external distraction (RED) osteogenesis describe the ability of multi-vector directional distraction control as opposed to univector internal distraction. There are currently limited data on the ability of the RED system to alter the maxillary occlusal pitch.The purpose of this study is to address the following clinical question: “Among cleft patients presenting with severe maxillary hypoplasia and treated with rigid external distraction, does the rigid external distraction system result in alteration of the maxillary pitch?”The study hypothesis is: among cleft patients presenting with maxillary hypoplasia treated with RED, the investigators hypothesize that there is no change in maxillary pitch with distraction.The study's specific aims are to design a retrospective cohort study and enroll a sample composed of cleft patients with maxillary hypoplasia treated with RED: 1) identify a cohort of patients with cleft maxillary hypoplasia, 2) quantify the degree of pre-operative maxillary hyperplasia, 3) measure changes in maxillary position achieved through RED. Materials and methodsTo address the research objectives, the investigators designed a retrospective cohort study. The study sample was derived from the population of patients with cleft maxillary hypoplasia who underwent RED by the Department of Oral and Maxillofacial Surgery at the University of Alabama - Birmingham from June 2007 to August 2019. Subjects eligible for study inclusion had cleft maxillary hypoplasia and underwent RED. Subjects were excluded if there were incomplete data collection or their records were not available for review.Demographic and radiographic variables were recorded. Demographics included gender, age at date of surgery, and history of ULCP vs. BLCP. Radiographic variables included standard cephalometric data recorded prior to distraction (T1) and after completion of distraction (T2). Methods of data analysisDescriptive statistics were computed for all study variables. Due to the potential for both positive and negative occlusal pitch change, a paired 2-tailed T-test was used to compare T1 and T2. The level of statistical significance was set at P < .05. ResultsThe study sample was composed of 45 subjects with a mean age at surgery of 12.2+3.4 years. Twenty-two (49%) were BCLP and 27 (60.0%) were male. At T1, mean SNA was 76.35+/-6.4 degrees, and the maxillary occlusal plane to Frankfort horizontal plane was 8.18+/-6.9 degrees. The mean anterior-posterior distraction distance was 11.4+/-5.7 mm. At T2, the mean SNA was 86.0+/-7.5 degrees, and the occlusal plane to FH was 3.78+/-7.3 degrees. The average maxillary occlusal pitch change was -4.4+/-5.8 degrees (P = .005). ConclusionFor cleft lip and palate patients with maxillary hypoplasia, surgical advancement with RED results in counterclockwise rotation of the maxillary occlusal plane.

A Posterior Rotational Flap Technique Using Distraction Osteogenesis for Unilateral Lambdoid Craniosynostosis.

The craniofacial asymmetry seen in unilateral lambdoid craniosynostosis may not be effectively treated by posterior cranial vault remodeling, endoscopic suturectomy, and helmet therapy, or suturectomy and distraction osteogenesis alone due to limitations in soft-tissue envelope expansion and relapse of the deformity. The authors report a series of unilateral lambdoid craniosynostosis patients treated with a posterior rotational cranial-flap technique using internal distraction osteogenesis. Posterior cranial vault reconstruction combined with internal distraction was used, aided by preoperative virtual surgical planning. An in situ posterior rotational flap osteotomy was utilized to maximize dural preservation. Primary outcome measures included age-adjusted volume change and age-adjusted percent volume change per mm distraction. Distraction characteristics and perioperative characteristics were also assessed. A total of 5 patients were identified. Mean predistraction intracranial volume was 1087.5 cc (SD = 202.3 cc) and mean postdistraction included intracranial volume was 1266.1cc (SD = 131.8cc). Mean age-adjusted percent included intracranial volume change was 14.1% (SD = 9.6%), and mean percent intracranial volume change per mm distraction was 0.43%/mm distraction (SD = 0.37%/mm distraction). One patient developed a distractor site infection postoperatively that was treated successfully with oral antibiotics. All patients had a Whitaker score of 1 at one year follow up. Posterior cranial vault remodeling using osteogenesis and a rotational cranial flap technique with dural preservation can be effectively used to maximize bone flap viability and limit postoperative relapse in patients with unilateral lambdoid craniosynostosis. Long term analysis as well as comparison to open techniques will need to be interrogated.

Clinical use of internal distraction osteogenesis in the rehabilitation of gunshot injuries of the mandible.

Rehabilitation of gunshot injuries that require combined reconstruction of bone and soft tissue poses a considerable challenge. We describe three cases of rehabilitation for mandibular defects and deformities caused by gunshot injuries. After debridement, three kinds of internal distractors were used. The bony transport discs were distracted about 10-22mm, and the new bone formed well in the distracted gaps. There was no evidence of infection during the consolidation period or follow up. Aesthetic appearance was also pleasing after treatment. Internal distraction osteogenesis after debridement might be a practical way of synchronously reconstructing bony and soft tissue after mandibular gunshot injuries.

Maxillary distraction osteogenesis and a Le Fort I osteotomy for severe maxillary retrognathia in cleft lip and palate: a case report

Abstract Background The correction of severe maxillary retrognathia in patients presenting with a cleft palate is challenging due to the complexity of the orthodontic preparation and the magnitude of the surgical movements required, along with the relatively high risk of relapse. Materials and methods An 18-year-old Caucasian male with a repaired left-side unilateral cleft lip and palate presented with concerns relating to poor facial aesthetics and poor occlusion. Multidisciplinary treatment involving orthodontics and orthognathic surgery were undertaken to correct the severe maxillary retrognathia. The correction involved the use of internal distraction osteogenesis followed by a conventional maxillary Le Fort I advancement with rotation. Results Pre- and post-treatment lateral cephalogram measurements showed the maxilla was advanced 18 mm, rotated clockwise producing a 9 mm increase in vertical dimension at A point and a 7 mm gain in relative arch width across the first molars. Follow-up CBCT superimpositions showed excellent skeletal stability of the achieved anterior-posterior, lateral and vertical corrections over a 2.4-year period, although there was some minor dental relapse. Conclusion This case report illustrates the successful use of orthodontics and distraction osteogenesis followed by conventional Le Fort I advancement surgery to correct a severely retrognathic maxilla in a patient with a repaired unilateral cleft lip and palate.

Comparison of Midface Advancement by External and Internal Craniofacial Distraction Osteogenesis.

Background:Distraction osteogenesis (DO) is employed to address the midface abnormalities using either an external DO (EDO) or an internal DO (IDO) device. There are few studies that have reported EDO and IDO outcomes through cephalometric evaluation. The aim of this retrospective, record-based study is to compare the change in position of the midface resulting from distraction of noncomplicated cases of Le Fort III osteotomies with EDO as well as IDO and compare the groups using standard right facing lateral cephalometry. We hypothesized that there would be no difference between EDO and IDO in terms of displacement (of point of reference) as well as complications.Materials and Methods:Retrospective analyses of cases fulfilling inclusion and exclusion criteria were retrieved from archives. Using two sets of right-side cephalometry, preoperative and after consolidation (at the end of the treatment), the changes in Point A and Orbitale (O) as described by Lima et al. were used for the study. Movement in X-axis and Y-axis was noted down and subjected to statistical analysis. Descriptive statistics, the coefficient of variability (expressed as percentage), and the interquartile range (maximum and minimum values) were presented. P ≤ 0.05 was taken as statistically significant.Results:Significant midface advancement was achieved with the procedure. There were five cases of EDO and eight cases of IDO. The age at which patients were operated ranged from 9 to 18 years (mean: 13 years). The mean follow-up time was for 14 ± 8 months. There were eight females (3 – EDO and 5 – IDO) and five males in total. There was no complication in the entire study group. The difference in total bone length gain along the horizontal axis was as follows: 12.19 and 12.84 along the Point A for EDO and IDO and 3.89 and 4.65 along the Point O for EDO and IDO, respectively. The difference was not statistically significant (P = 0.833 and 0.622, respectively). The total movement along the vector at Point A in EDO and IDO was 13.08 and 12.56, respectively, the difference of which was not statistically significant (P = 1); while along the vector at Point O in EDO and IDO, the total movement was 10.98 and 11.48, respectively, the difference of which was not again statistically significant (P = 0.833).Discussion:The significance of the difference in EDO and IDO is discussed using the biomechanical principles and the results deliberated based on the existing literature.Conclusion:The positioning of the devices plays a significant role in deciding the outcome. Both the distractors have their distinct advantages and their applications have to be customized.

Improvement in the airway after mandibular distraction osteogenesis surgery in children with temporomandibular joint ankylosis and mandibular hypoplasia.

Temporomandibular joint (TMJ) ankylosis accompanied by mandibular micrognathia can severely obstruct a patient's upper airway. The obstructive sleep apnea and hypopnea syndrome (OSAHS) resulting from TMJ ankylosis and accompanied by mandibular micrognathia, can severely influence the patient's life. The aim of this study was to determine if there is a difference in Cormack and Lehane score before and after distraction osteogenesis in such patients, and to evaluate the airway changes and the respiratory outcome using polysomnography after mandibular distraction osteogenesis. This observational prospective study was carried out on 30 ASA II patients with micrognathia and TMJ ankylosis undergoing internal distraction osteogenesis. All patients were assessed with polysomnography before surgery and 6 month after surgery. Nasal intubation was done using a fiberoptic bronchoscope, then patients were subjected to the same anesthetic protocol. Direct laryngoscopy was attempted for the Cormack and Lehane grading after induction. The Cormack and Lehane grade was reassessed after facial symmetry was obtained on removal of the distractor. Mouth opening and Cormack and Lehane score improved significantly between the initial presentation for placement of mandibular distraction osteogenesis devices and on removal of the destructor under general anesthesia. Polysomnographic studies conducted after distraction confirmed the correction of airway obstruction in all patients: Improvement in Apnea-Hypopnea Index, mean difference (95% CI), 39.8 (38.8-40.9); the number of apneas per hour, mean difference, (95% CI) 41.1 (42.1-40.1); and oxygen-desaturation-index mean difference (95% CI) 27.6 (28.3-26.8). Mandibular distraction osteogenesis improved laryngeal view. Distraction osteogenesis can be successfully used for the treatment of obstructive sleep apnea in mandibular hypoplasia patients.

The evaluation of maxillary advancement technique using internal distraction osteogenesis in unilateral cleft lip and palate patient with finite element analysis

The aim of this study is to evaluate the parameters that commonly used in mechanical analysis of materials like displacement, strain and von Misses stress distributions after maxillary advancement in unilateral cleft lip and palate (UCLP) patients using distraction osteogenesis. The 3D skull model of a 20-year-old UCLP patient with normal mandibular development (SNB: 79.5 o ) and maxillary hypoplasia (SNA: 70.7°) with negative overjet was reconstructed by using the computed tomography (CT) data. The surface mesh of the model was prepared by using the MIMICS software, and then the model was transferred into ANSYS (FE package). 854023 nodes and 623177 elements (Solid92) were used during the analysis. To obtain more realistic model, the maxillary cortical bone was defined as anisotropic. On the other hand the material properties of trabecular bone and callus were selected as linear, isotropic and homogenous. After a LeFort I osteotomy was performed on the model, the maxillary advancement was simulated in 6 steps with 1 mm translation in each step with a total of 6 mm displacement. Non-linear finite element analysis was used due to large deformations. Compared to the similar studies, more elements and nodes were defined especially in maxilla and zygoma. Selection of material properties of maxillary cortical bone has an important role on the calculation of bone strain and deformations during the finite element analysis (FEA). Therefore, the maxillary cortical bone was defined as anisotropic. Asymmetrical displacements and von Misses stresses were found in both right and left half-jaw. The maximum stresses were obtained at foramen infraorbitale and infraorbital margin regions at non-cleft side (mean 350 and 410 MPa, respectively). Relatively high von Misses stresses were found on sutura naso-maksillaris, fronto-nasalis, and zygomaticomaksillaris. Sagittal displacements of anterior nasal spina and point A were found to be 6.24 and 6.65 mm, respectively. The difference in the displacements was due to the asymmetrical anatomical structure in CLP patients. In this study the finite element method has been used to simulate the sagittal maxillary advancement. The simulation results obtained from numerical method show that asymmetrical stresses and displacements in the sagittal plane in UCLP patients reveal the difference in routine patients. Non-invasive methods such as the FEA help us to determine the mechanical response of the skull before any treatment is applied to the patients.

Internal Distraction Osteogenesis to Correct Symptomatic Cephalocranial Disproportion

Cephalocranial disproportion describes a state of volume mismatch between brain size and intracranial space. Nonsyndromic single-suture craniosynostosis patients can present with symptoms from elevated intracranial pressure because of inadequate or delayed treatment. The purpose of this study was to present five sagittal synostosis children with symptomatic cephalocranial disproportion treated with cranial vault distraction osteogenesis. Asymmetric transverse internal distraction osteogenesis was performed to preferentially expand the posterior cranium. A wider base plate, pivot screw, anterior hinge plate, and flexible drive rod were applied to minimize device failure while accomplishing lateral rotation of parietal bones. A distraction protocol was developed and produced consistent results. Two girls and three boys underwent distraction for sagittal synostosis between 2002 and 2006. Average age at surgery was 5.8 years. All had resolution or amelioration of preoperative symptoms. Average operating room time for distractor placement was 2.5 hours (152 minutes) and average hospital stay was 2.8 days. The average distracted distance was 14.4 mm. Average operating room time for distractor removal was 1.1 hours (69 minutes) and average hospital stay was 1.6 days. No perioperative complications occurred. Average follow-up period was 4.2 years, with no recurrence of symptoms. Symptomatic cephalocranial disproportion can present in older children with craniosynostosis. Asymmetric transverse distraction of the posterior cranial vault is a safe and effective treatment modality for this population.

Simultaneous Correction of Bilateral Temporomandibular Joint Ankylosis With Mandibular Micrognathia Using Internal Distraction Osteogenesis and 3-Dimensional Craniomaxillofacial Models

The present study evaluated the simultaneous correction of bilateral temporomandibular joint ankylosis with mandibular micrognathia using internal distraction osteogenesis (DO) with the help of a 3-dimensional craniomaxillofacial model technique. A total of 16 patients (age 18 to 43 years) with bilateral temporomandibular joint ankylosis and mandibular micrognathia were included in the present study. Obstructive sleep apnea and hypopnea syndrome was diagnosed in all patients preoperatively. Three-dimensional craniomaxillofacial models of the 16 patients were constructed using computed tomography and a rapid prototype technique. Simulation surgery and individual internal DO was performed on the models. The treatment included simultaneous DO of the mandibular body and transport DO for temporomandibular joint arthroplasty. The distraction was started on the seventh day after surgery. The distraction rate was 0.8 mm/day. The patients began active mouth opening postoperatively. Distracters were kept in place for 4 months after distraction completion and then removed. Polysomnography, cephalometry, and computed tomography were performed at 6 months postoperatively. The obstructive sleep apnea and hypopnea syndrome was cured, and the micrognathia was corrected in all patients. The average mouth opening increased from 4.6 mm preoperatively to 33.5 mm postoperatively. The average range of the sella-nasion-supramental angle increased from 68.7 degrees preoperatively to 77.6 degrees postoperatively. Bone formation in the distraction gaps was observed. The follow-up period was 29.7 months (range 6 to 52). No complications or recurrence of temporomandibular joint ankylosis or micrognathia occurred in any patient during the follow-up period. Bilateral temporomandibular joint ankylosis accompanied by mandibular micrognathia and obstructive sleep apnea and hypopnea syndrome can be corrected effectively by simultaneous internal DO. The application of preoperative simulation surgery using 3-dimensional craniomaxillofacial model has many advantages for planning the surgical method and precise operation. Our preliminary results have shown that it is a safe, effective, and feasible technique.

Rapid manufacture of custom‐fitting surgical guides

PurposeThe computer‐aided design (CAD) and manufacture of custom‐fitting surgical guides have been shown to provide an accurate means of transferring computer‐aided planning to surgery. To date guides have been produced using fragile materials via rapid prototyping techniques such as stereolithography (SLA), which typically require metal reinforcement to prevent damage from drill bits. The purpose of this paper is to report case studies which explore the application of selective laser melting (SLM) to the direct manufacture of stainless steel surgical guides. The aim is to ascertain whether the potential benefits of enhanced rigidity, increased wear resistance (negating reinforcement) and easier sterilisation by autoclave can be realised in practice.Design/methodology/approachA series of clinical case studies are undertaken utilising medical scan data, CAD and SLM. The material used is 316L stainless steel, an alloy typically used in medical and devices and surgical instruments. All treatments are planned in parallel with existing techniques and all guides are test fitted and assessed on SLA models of the patients' anatomy prior to surgery.FindingsThis paper describes the successful application of SLM to the production of stainless steel surgical guides in four different maxillofacial surgery case studies. The cases reported address two types of procedure, the placement of osseointegrated implants for prosthetic retention and Le Fort 1 osteotomies using internal distraction osteogenesis. The cases reported here have demonstrated that SLM is a viable process for the manufacture of custom‐fitting surgical guides.Practical implicationsThe cases have identified that the effective design of osteotomy guides requires further development and refinement.Originality/valueThis paper represents the first reported applications of SLM technology to the direct manufacture of stainless steel custom‐fitting surgical guides. Four successful exemplar cases are described including guides for osteotomy as well as drilling. Practical considerations are presented along with suggestions for further development.

The Reconstruction of Bony Support following Maxillectomy by Internal Curvilinear Distraction Osteogenesis of the Zygoma

The Reconstruction of Bony Support following Maxillectomy by Internal Curvilinear Distraction Osteogenesis of the Zygoma

P.141 Construction of a database of the cranio-maxillo-facial bones

The present study evaluated the simultaneous correction of bilateral temporomandibular joint ankylosis with mandibular micrognathia using internal distraction osteogenesis (DO) with the help of a 3-dimensional craniomaxillofacial model technique.A total of 16 patients (age 18 to 43 years) with bilateral temporomandibular joint ankylosis and mandibular micrognathia were included in the present study. Obstructive sleep apnea and hypopnea syndrome was diagnosed in all patients preoperatively. Three-dimensional craniomaxillofacial models of the 16 patients were constructed using computed tomography and a rapid prototype technique. Simulation surgery and individual internal DO was performed on the models. The treatment included simultaneous DO of the mandibular body and transport DO for temporomandibular joint arthroplasty. The distraction was started on the seventh day after surgery. The distraction rate was 0.8 mm/day. The patients began active mouth opening postoperatively. Distracters were kept in place for 4 months after distraction completion and then removed. Polysomnography, cephalometry, and computed tomography were performed at 6 months postoperatively.The obstructive sleep apnea and hypopnea syndrome was cured, and the micrognathia was corrected in all patients. The average mouth opening increased from 4.6 mm preoperatively to 33.5 mm postoperatively. The average range of the sella-nasion-supramental angle increased from 68.7° preoperatively to 77.6° postoperatively. Bone formation in the distraction gaps was observed. The follow-up period was 29.7 months (range 6 to 52). No complications or recurrence of temporomandibular joint ankylosis or micrognathia occurred in any patient during the follow-up period.Bilateral temporomandibular joint ankylosis accompanied by mandibular micrognathia and obstructive sleep apnea and hypopnea syndrome can be corrected effectively by simultaneous internal DO. The application of preoperative simulation surgery using 3-dimensional craniomaxillofacial model has many advantages for planning the surgical method and precise operation. Our preliminary results have shown that it is a safe, effective, and feasible technique.

P.142 Features of oral cancer shown by borono-phenylalanine PET

The present study evaluated the simultaneous correction of bilateral temporomandibular joint ankylosis with mandibular micrognathia using internal distraction osteogenesis (DO) with the help of a 3-dimensional craniomaxillofacial model technique.A total of 16 patients (age 18 to 43 years) with bilateral temporomandibular joint ankylosis and mandibular micrognathia were included in the present study. Obstructive sleep apnea and hypopnea syndrome was diagnosed in all patients preoperatively. Three-dimensional craniomaxillofacial models of the 16 patients were constructed using computed tomography and a rapid prototype technique. Simulation surgery and individual internal DO was performed on the models. The treatment included simultaneous DO of the mandibular body and transport DO for temporomandibular joint arthroplasty. The distraction was started on the seventh day after surgery. The distraction rate was 0.8 mm/day. The patients began active mouth opening postoperatively. Distracters were kept in place for 4 months after distraction completion and then removed. Polysomnography, cephalometry, and computed tomography were performed at 6 months postoperatively.The obstructive sleep apnea and hypopnea syndrome was cured, and the micrognathia was corrected in all patients. The average mouth opening increased from 4.6 mm preoperatively to 33.5 mm postoperatively. The average range of the sella-nasion-supramental angle increased from 68.7° preoperatively to 77.6° postoperatively. Bone formation in the distraction gaps was observed. The follow-up period was 29.7 months (range 6 to 52). No complications or recurrence of temporomandibular joint ankylosis or micrognathia occurred in any patient during the follow-up period.Bilateral temporomandibular joint ankylosis accompanied by mandibular micrognathia and obstructive sleep apnea and hypopnea syndrome can be corrected effectively by simultaneous internal DO. The application of preoperative simulation surgery using 3-dimensional craniomaxillofacial model has many advantages for planning the surgical method and precise operation. Our preliminary results have shown that it is a safe, effective, and feasible technique.

P.140 Considerations on the fleld of view of cone beam devices

The present study evaluated the simultaneous correction of bilateral temporomandibular joint ankylosis with mandibular micrognathia using internal distraction osteogenesis (DO) with the help of a 3-dimensional craniomaxillofacial model technique.A total of 16 patients (age 18 to 43 years) with bilateral temporomandibular joint ankylosis and mandibular micrognathia were included in the present study. Obstructive sleep apnea and hypopnea syndrome was diagnosed in all patients preoperatively. Three-dimensional craniomaxillofacial models of the 16 patients were constructed using computed tomography and a rapid prototype technique. Simulation surgery and individual internal DO was performed on the models. The treatment included simultaneous DO of the mandibular body and transport DO for temporomandibular joint arthroplasty. The distraction was started on the seventh day after surgery. The distraction rate was 0.8 mm/day. The patients began active mouth opening postoperatively. Distracters were kept in place for 4 months after distraction completion and then removed. Polysomnography, cephalometry, and computed tomography were performed at 6 months postoperatively.The obstructive sleep apnea and hypopnea syndrome was cured, and the micrognathia was corrected in all patients. The average mouth opening increased from 4.6 mm preoperatively to 33.5 mm postoperatively. The average range of the sella-nasion-supramental angle increased from 68.7° preoperatively to 77.6° postoperatively. Bone formation in the distraction gaps was observed. The follow-up period was 29.7 months (range 6 to 52). No complications or recurrence of temporomandibular joint ankylosis or micrognathia occurred in any patient during the follow-up period.Bilateral temporomandibular joint ankylosis accompanied by mandibular micrognathia and obstructive sleep apnea and hypopnea syndrome can be corrected effectively by simultaneous internal DO. The application of preoperative simulation surgery using 3-dimensional craniomaxillofacial model has many advantages for planning the surgical method and precise operation. Our preliminary results have shown that it is a safe, effective, and feasible technique.

Vector Control in Alveolar Distraction Osteogenesis

Distraction osteogenesis is a surgical technique which utilizes the body's own reparative mechanisms for hard and soft tissue reconstruction. It has numerous applications in the maxillofacial complex, and has been successfully used for vertical and horizontal augmentation of alveolar ridges future prior to implant placement. In our opinion, this method is a useful and acceptable alternative to conventional bone grafting techniques in a selected group of patients. Although the concept of alveolar distraction is exciting, and has certain specific advantages (eg, soft tissue regeneration, predictable augmentation of height in the posterior mandible), optimal vector control of the distraction regenerate remains an issue of critical importance. The purpose of this article is to present our experience with some simple techniques that we have successfully used at our center for proper vector control during internal alveolar distraction osteogenesis.

A Novel Method for Measuring and Monitoring Monobloc Distraction Osteogenesis Using Three-Dimensional Computed Tomography Rendered Images With the "Biporion-Dorsum Sellae" Plane.

The aim was to assess the stability of monobloc distraction osteogenesis using three-dimensional computed tomographic (CT) scan volume-rendered images with the "biporion-dorsum sellae" plane. This was a prospective study of patients undergoing monobloc internal distraction osteogenesis at the International Craniofacial Institute, Dallas, TX. Measurements were made of the perpendicular distance of 8 skeletal facial points to the static "biporion-dorsum sellae" plane. The statistical analyses were performed with the paired-samples t test in SPSS. Three male patients were included in the study. Of these patients, 2 had Apert syndrome (A, B) and 1 had Carpenter syndrome (C). The mean age was 73 (range 30-112) months, and the mean follow up was 14 (range 8-12) months. The consolidation period was 17, 23, and 28 weeks in each patient, respectively. In patient A, the paired-samples t test of matched points was P = 0.022. Further analysis of the three-dimensional lateral profile revealed an obvious relapse, and predistractor removal CT scans (at 17 weeks) also showed deficient bone growth across the distraction gaps at the anterior cranial fossae and the temporal bones. In contrast, patients B and C showed a stable outcome after distraction and after removal of distraction devices. On analysis of the predistractor removal three-dimensional CT scans (23 and 28 weeks, respectively), there was more bone growth across the distraction gaps at the anterior cranial fossa and temporal bones. The "biporion-dorsum sellae" plane was used to assess the results of monobloc distraction osteogenesis. Relapse was associated with inadequate bone growth across the anterior cranial fossa and temporal bone. The findings seem to point the way for an increased consolidation period and more detailed examination of the CT scans before removal of internal distraction devices.

Internal Distraction Osteogenesis in Mandibular Reconstruction: Clinical Experience in 10 Cases

Distraction osteogenesis has been used for reconstruction of bone and soft-tissue defects. The authors present their clinical experience in the reconstruction of mandibular segmental defects by means of internal distraction osteogenesis. Ten patients with mandibular defects ranging from 30 to 80 mm in length were treated in the authors' department. Internal distraction devices with transcutaneous activators were placed immediately after complete resection of the affected bone. Distraction was initiated 10 days after surgery at a rate of 0.5 mm/day. The consolidation period ranged from 12 to 22 weeks. Finally, the distractor device was removed. In two patients, an additional iliac crest bone graft was needed to complete bone union. Follow-up ranged from 4 to 47 months after surgery. Partial cutaneous and intraoral exposure was observed in two patients. At the end of the follow-up period, successful distraction osteogenesis was achieved in eight patients. Six patients were alive and free of disease, whereas two patients showed local relapse and required new resective surgery. Complete intraoral exposure with failure of the distraction process was observed in one patient, whereas another patient did not complete distraction because of metastatic disease diagnosed 4 months after surgery. Good clinical results for reconstruction of mandibular and soft-tissue postablative defects are reported with the use of this technique. The use of semiburied devices provides better aesthetics and acceptable quality of life to the patients. Larger series are required to popularize the use of this procedure.

Exorbitism Correction of Faciocraniosynostoses by Monobloc Frontofacial Advancement With Distraction Osteogenesis

Monobloc frontofacial advancement with internal distraction osteogenesis is still a relatively new technique, and the literature on exorbitism correction of syndromal faciocraniosynostosis with monobloc advancement is scarce. Using a image processing software, we measured on axial computed tomographic scans the effect of monobloc advancement on the correction of exorbitism on a large series of patients (n=38) with syndromal faciocraniosynostosis who underwent surgery for correction of cranial and facial hypoplasia. A population reference of 23 patients without faciocraniosynostoses was also measured. For each orbit, globe protrusion was expressed as the ratio between the length of the globe that is above the interzygomatic line and eye size. The results indicate that monobloc has a symmetrical effect on both eyes that is correlated to the preoperative degree of exorbitism. Longitudinal data indicate that exorbitism correction changes with time. A mean preoperative globe protrusion of 0.86 dropped sharply to 0.54 at 6 months after distraction and increased to 0.61 at 16 months after distraction removal, a value that is not significantly different from the ratio of the control group (0.60). Overall, the data suggest that a certain degree of enophthalmos in the early postoperative period does not necessarily imply a sustained overcorrection.

The Use of Internal Maxillary Distraction for Maxillary Hypoplasia: A Preliminary Report

Distraction osteogenesis is a useful alternative to advance the maxilla in complicated cases of maxillary hypoplasia. The purpose of this article is to review the workup, experience, and preliminary results with the use of internal distraction osteogenesis for maxillary hypoplasia at one teaching institution. Over a 5-year period, more than 300 patients with craniofacial and dentofacial defects have undergone oral and maxillofacial surgery at our center to correct their skeletal discrepancies. Of these, 10 have had maxillary distraction osteogenesis done with internal distractors. Follow-up of 6 months or more was available for 8 patients. Stereolithographic models were used to bend distractors prior to surgery in 6 patients. Latency prior to the start of distraction was 3 to 7 days and varied with the age of the patient. Distraction occurred at approximately 1 mm per day with an average distraction length of 8.5 mm (range, 6-10 mm). Excellent occlusal results were obtained in 5 patients. Major complications including nonunion and failure to achieve acceptable occlusal results were observed in 3 patients. Minor complications including pain and loosening of the distracter devices were observed in 2 patients, but did not appear to affect the esthetic and functional results. Distraction osteogenesis is a useful alternative to traditional orthognathic surgery to treat maxillary hypoplasia. Internal distractions are attractive to patients, but are more difficult to place and can cause discomfort to patients when trying to achieve an ideal primary vector of distraction. Stereolithographic models can help with placement of the device. Changes in design of distractors may help with patient discomfort.