Comparison of methods for assigning the material properties of the distraction callus in computational models.

In silico models of distraction osteogenesis and fracture healing usually assume constant mechanical properties for the new bone tissue generated. In addition, these models do not always account for the porosity of the woven bone and its evolution. In this study, finite element analyses based on computed tomography (CT) are used to predict the stiffness of the callus until 69 weeks after surgery using 15 CT images obtained at different stages of an experiment on bone transport, technique in which distraction osteogenesis is used to correct bone defects. Three different approaches were used to assign the mechanical properties to the new bone tissue. First, constant mechanical properties of the hard callus tissue and no porosity were assumed. Nevertheless, this approach did not show good correlations. Second, random variations in the elastic modulus and porosity of the woven bone were taken from previous experimental studies. Finally, the elastic properties of each element were assigned depending on gray scale in CT images. The numerically predicted callus stiffness was compared with previous in vivo measurements. It was concluded firstly that assignment depending on gray scale is the method that provides the best results and secondly that the method that considers a random distribution of porosity and elastic modulus of the callus is also suitable to predict the callus stiffness from 15 weeks after surgery. This finding provides a method for assigning the material properties of the distraction callus, which does not require CT images and may contribute to improve current in silico models.

National 30-Day Outcomes for Posterior Cranial Vault Distraction.

BACKGROUND: Posterior vault distraction (PVD) can rapidly expand calvarial volume in infancy. Limited data exist regarding its perioperative and postoperative safety profile. This study sought to investigate the patient profile, outcomes, and safety of PVD using a national pediatric database. METHODS: Posterior vault distraction patients between 2012 and 2016 were isolated from the National Surgical Quality Improvement Program Pediatric database. Patient background, perioperative outcomes, and risk factors were analyzed using chi-squared, t test analysis, and multivariate regression. RESULTS: Ninety-four patients who underwent PVD were isolated with 67 ultimately meeting inclusion criteria for the study. The majority of patients undergoing PVD had limited other documented comorbidities. No patients required reoperation or 30-day readmission. There were no incidences of stroke, surgical site infection, or death. Subdividing outcomes by specialty, plastic surgeons performed PVD on significantly older patients than neurosurgeons (188 days vs 138 days, P = 0.008). Increasing age was associated with increasing operative time (P < 0.001). Furthermore, increasing age is associated with greater absolute transfusion requirements (P = 0.018) and higher, but not significant, risk of requiring any volume of blood transfusion (P = 0.105). CONCLUSIONS: Posterior vault distraction is a safe procedure to rapidly expand calvarial volume in the setting of craniosynostosis. Increasing patient age is the strongest predictor for prolonged operative time and higher blood transfusion volumes.

Surgeon Experience Does Not Change Rate of Perioperative Surgical Complication in Rib-Based Distraction Surgery for Early-Onset Scoliosis.

OBJECTIVE: To report on the surgical learning curve in treating early-onset scoliosis with rib-based distraction. SUMMARY OF BACKGROUND DATA: The idea of a surgical learning curve proposes improved outcomes with experience. Early-onset scoliosis (EOS) is a challenging condition to treat and complication rates are high. METHODS: All patients from a single experienced spine surgeon's practice who had undergone placement of rib-based distraction constructs between 2002 and 2013 were identified. A retrospective chart review was performed to determine patient characteristics at implantation and follow-up surgeries and complications. The primary outcome was complication rate per surgical encounter. Experience was analyzed both by number of surgical procedures and year in study period. RESULTS: The surgeon began using rib-based distraction in 2002, and between 2002 and 2013, a total of 101 patients underwent 1,009 implantation or expansion surgeries involving rib-based distraction at a median age of 6 years at implantation (10 months-9.4 years). The median preoperative Cobb angle was 67° (8°-125°; IQR: 57°-76°) and follow-up was a median of 4.4 years (IQR 3.7-5.6 years). Overall, 65.3% of patients experienced complications, including 40 Grade I, 20 Grade II, 126 Grade IIA, and 3 Grade III. Univariate analysis identified a trend toward cumulative number of surgeries relating to a decreased complication rate, with every 50 surgeries decreasing the complication rate by 3% (p = .071). However, multivariate analysis found cumulative number of surgeries and complication rate to not be significantly related (p = .12). Surgeon experience as measured by study time (as both a continuous and categorical predictor) did not achieve statistical significance in either the univariate or multivariate models. CONCLUSION: This is the largest single-surgeon series of EOS patients treated with rib-based distraction. Surgeon experience defined either as number of procedures or years of experience within the study period did not impact the rate of complications.

Perioperative outcomes and management in midface advancement surgery: a multicenter observational descriptive study from the Pediatric Craniofacial Collaborative Group.

BACKGROUND/AIMS: The evolution of Le Fort III and Monobloc procedures with utilization of distraction devices has resulted in shortened surgical times, greater facial advancements, and decreased transfusion requirements. The aim of this observational study was to utilize data from the multicenter Pediatric Craniofacial Surgery Perioperative Registry to present and compare patient characteristics and outcomes in children undergoing midface advancement with distraction osteogenesis. METHODS: We queried the Pediatric Craniofacial Surgery Perioperative Registry for children undergoing midface advancement involving distractor application from June 2012 to September 2016. Data extracted included demographics, perioperative management, complications, fluid and transfusion volumes, and length of stay. The extracted patient characteristics and perioperative variables were summarized and compared. RESULTS: The query yielded 72 cases from 11 institutions: 49 children undergoing Le Fort III and 23 undergoing Monobloc procedures. Monobloc patients were younger, weighed less, and more likely to have tracheostomies along with elevated intracranial pressure. Greater transfusion was observed in the Monobloc group for nearly all of the transfusion outcomes evaluated. Median ICU and hospital length of stay were 2 and 3 days longer, respectively, in the Monobloc group. Perioperative complications were not uncommon, occurring in 18% of patients in the Le Fort III group and 30% in the Monobloc group. CONCLUSION: Monobloc procedures were associated with greater transfusion and longer ICU and hospital length of stay. Perioperative complications were more prevalent in the Monobloc group.

A Quantitative Analysis of Weight Gain Following Mandibular Distraction Osteogenesis in Robin Sequence.

Mandibular distraction osteogenesis (MDO) is an effective treatment modality for children suffering from upper airway obstruction from Robin Sequence (RS). Mandibular distraction osteogenesis has been shown to have positive effects on oral feeding and for relieving respiratory obstruction, but its effects on postoperative weight gain are poorly understood. This study quantitatively analyzes weight gain following MDO. A retrospective chart review identified 22 RS children who underwent MDO. Patient weight data, feeding methods pre- and postoperatively, and polysomnography data pre- and postoperatively were collected. Each patient's weight plotted over time was then compared with his or her closest standardized growth curve, and linear regression analysis was utilized to quantify patient growth by calculating actual and expected average daily weight gain (g/d). Percentile changes were analyzed as well. Children gained significantly less weight than expected from birth to time of MDO and significantly more weight than expected from MDO to device removal, MDO to 6 months postoperatively, and MDO to 12 months postoperatively. The average growth percentile for the cohort was 37.3 at birth, declined to 22.7 by MDO, and increased to 28.5 and 33.5 at device removal and 6 months postoperatively, respectively. More than 70% of children were exclusively orally fed within 6 months of MDO. Children with isolated Robin Sequence had superior weight gain than children with syndromic Robin Sequence following surgery. In conclusion, MDO helps improve weight gain following surgery, particularly for infants with isolated Robin Sequence, and has positive effects on oral feeding and respiration.

Long-Term Skeletal Changes After Maxillary Distraction Osteogenesis in Growing Children With Cleft Lip/Palate.

PURPOSE: To systematically evaluate the skeletal changes after maxillary distraction osteogenesis (DO) in growing patients with cleft lip with or without cleft palate (CL/P). MATERIALS AND METHODS: Electronic databases, gray literature, and reference list searches were conducted. Articles reporting prospective and retrospective studies that included patients <16 years old (N ≥ 6) who had received DO surgery for correction of a midfacial hypoplasia due to CL/P, and the period of follow-up persisted >1 year were reviewed. The original articles were evaluated by 2 investigators to ensure that they met the selection criteria. A methodologic quality assessment tool was used to evaluate the quality of selected studies. Twenty-six studies met the initial search criteria, and 9 articles included 101 growing patients with maxillary hypoplasia due to CL/P who received DO surgery were finally selected and analyzed. RESULTS: The results showed that long term after maxillary advancement with DO, the horizontal relapse in A-point was <15% in 3 studies, 20% to 25% in 1 study, 30% to 35% in 3 studies, and >40% in 1 study. Totally, the range of horizontal relapse in A-point was 11.9% to 45.9%. Similarly, the relapse in SNA angle was <30% in 1 study, 30% to 40% in 3 studies, and >40% in 2 studies. Totally, the range of relapse in SNA was 25.7% to 77%. Two studies showed that the vertical relapse in A-point were 137% and 208%, and in the PNS point were 65% and 62.7%. CONCLUSION: Although findings demonstrated that DO is an effective treatment method for severe maxillary hypoplasia in growing patients with CL/P, there is a relatively high amount of skeletal relapse both in horizontal and vertical dimension. Thus, the first proposed alternative for CL/P patients would be to select the correct primary procedure to decrease damage and avoid unnecessary scars. Then appropriate preoperative and postoperative care is necessary to prevent postoperative relapse. In addition, overcorrection also may be a possible alternative for compensation of postoperative relapse.

Femoral nonunion with segmental bone defect treated by distraction osteogenesis with monolateral external fixation.

BACKGROUND: Currently, the common treatment for femoral nonunion with large segmental bone defect is difficult and complex. The effective surgical methods are rare, include vascularized bone grafting, Masquelet technique and Ilizarov distraction osteogenesis. The objective of this study is to investigate the outcomes of segmental femoral defects treated with monolateral external fixation using the distraction osteogenesis. METHODS: We retrospectively analyzed patients with femoral nonunion with segmental bone defects (> 6 cm) between January 2010 and January 2014 in our single trauma center. All patients were treated by distraction osteogenesis with monolateral external fixation. All surgeries were performed by the same surgeon. Bone union, duration of distraction osteogenesis in days, time to consolidation in months, external fixation index (EFI), complications, and additional surgical interventions were recorded postoperatively. The modified Application of Methods of Illizarov (ASAMI) criteria were used to evaluate the operative effectiveness. RESULTS: Forty-one patients were enrolled in this study for analysis. The length of the bone defect ranged from 6 to 17 cm. All patients eventually achieved healing, and no patient experienced recurrence of infection or newly developed infection. The average time needed for healing was 13 months. In terms of the incidence of complications, 3 cases axial deviations, 5 cases docking site nonunion, 23 cases pin-tract infection, 14 cases knee joint stiffness or their joint mobility declined, 2 cases osteogenesis insufficient in the distraction area,1 case refracture, and 2 cases loose external fixation pins. In terms of the evaluations of fracture healing and function, 30 patients excellent, 6 patients good, 5 patients fair, and 0 patient poor. In terms of postoperative function evaluations, 21 patients excellent, 9 patients good, 7 patients fair, and 4 patients poor. CONCLUSION: For patients with femoral nonunion with large segmental bone defects, the monolateral external fixation can provide effective stability, improve compliance, and reduce complications.

Complications associated with surgically assisted rapid palatal expansion without pterygomaxillary separation.

INTRODUCTION: The purpose of this retrospective clinical study was to evaluate the surgical complications associated with the surgically assisted rapid palatal expansion (SARPE) which does not involve pterygomaxillary separation (PMS). PATIENTS AND METHODS: A total of 40 (25 females, 15 males) skeletally mature patients, who had the diagnosis of maxillary transverse maxillary deficiency (TMD), were treated surgically under local or general anesthesia. The mean follow-up time was 6 months. RESULTS: Recorded perioperative and postoperative complications were discussed within the current literature. No serious complications were observed intraoperatively. Eight patients (20%) showed postoperative complications including neurosensory deficits, maxillary sinus infection, epistaxis, fistula formation and incisional dehiscence. DISCUSSION: Neurosensory deficits were the most common findings. The present findings suggest that minor complications were observed associated with SARPE without PMS. The technique may be performed safely also under local anesthesia.

Neonatal Micrognathia: National Trends in Early Mandibular Surgery.

BACKGROUND: Micrognathia is a congenital anomaly that may pose breathing and feeding limitations in newborns, sometimes necessitating invasive management. The present study aims to identify the complications associated with receiving mandibular surgery during the birth stay in order to better predict which patients may benefit from early surgical intervention. METHODS: A retrospective cohort study was performed using the 2000 to 2012 kids' inpatient databases. We included all live newborn infants born in the hospital through vaginal delivery or caesarean section. We used multivariate logistic regression to investigate the demographic and clinical factors associated with receiving mandibular surgery for micrognathia during the birth stay. RESULTS: Of 19,638,453 births, 999 were diagnosed with micrognathia (0.005%). Forty (4%) patients with micrognathia underwent mandibular surgery during the initial admission. On univariate analysis in newborns with micrognathia, mandibular surgery during birth stay was associated with cleft palate, apnea, intubation, tracheostomy, obstructive sleep apnea (OSA), and long mechanical ventilation. Multivariate analysis supported the association between mandibular surgery during the initial admission and long mechanical ventilation (odds ratio [OR], 24.6; 95% confidence interval [CI], 7.7-78.5), OSA (OR, 24.9; 95% CI, 2.5-261.8), apnea (OR, 4.2; 95% CI, 1.5-11.3), and cleft palate (OR, 4.6; 95% CI, 2.0-10.6). However, intubation and tracheostomy were not found to be associated with early mandibular surgery during the birth stay. CONCLUSIONS: The present study identified long mechanical ventilation, apnea, cleft palate, and OSA as factors indicating patients who may benefit from early mandibular surgery, such as mandibular distraction osteogenesis. These findings may bring the clinician closer to standardizing the indications for early mandibular distraction osteogenesis.

[Congenital malformations of the temporo-mandibular joint and the mandibular ramus: Grafting vs distraction osteogenesis]. / Malformations congénitales des articulations temporo-mandibulaires et des branches mandibulaires : quand greffer ? Quand distracter ?

Congenital deformities of the mandibular ramus and of the temporo-mandibular joint are treated by surgery since the early 20th century. However, morphological and functional results are often disappointing, accounting for iterative operations. Today, a clear consensus concerning the type of intervention to be proposed, and at what age it should be carried out does not yet exist. For mild cases, "conventional" orthognathic or osteogenic distraction procedures seem to work well, especially if they are carried out at the end of growth. In severe cases, it is often necessary to proceed in several surgical steps, usually starting with a chondrocostal graft, especially when interceptive surgery, performed before the end of growth, is preferred in order to improve the patient's quality of life.

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

BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

Will the right Robin patient rise, please? Definitions and criteria during management of Robin sequence patients in the Netherlands and Belgium.

BACKGROUND: Robin Sequence (RS) is characterized by micrognathia and upper airway obstruction (UAO), with or without cleft palate, causing respiratory and feeding problems. Management options are: positioning; nasopharyngeal airway (NPA); tongue-lip adhesion (TLA); mandibular distraction (MDO); and tracheostomy. Controversy exists in literature regarding RS definition and management. Here we describe definitions, management strategies and criteria in opting for management strategies, used by Dutch and Belgian cleft teams. METHODS: A specifically designed questionnaire was sent to members of all 16 Dutch and Belgian cleft teams. RESULTS: 14 cleft teams returned 35 questionnaires. All used micrognathia as definition criterion, 93.4% cleft palate, 51.5%glossoptosis and 45.7% UAO. Six different RS definitions were used; even within a single team >1 definition was used. All teams used different management strategies: all used positioning, 10 NPA, 6 TLA, 7 MDO, 8 tracheostomy, 5 refer patients with invasive treatment indication. Criteria in opting management modalities were: O2-saturation (89.3%), clinical presentation (86.2%), growth and feeding problems (69.0%), polysomnography (62.1%), and differed within teams. CONCLUSION: The Dutch and Belgian cleft teams use variable RS definitions, different management modalities and criteria in choosing management strategies. A single, strict definition and evidence-based management guidelines should be formulated for optimal patient care.

Review of orthognathic surgery and related papers published in the British Journal of Oral and Maxillofacial Surgery 2011-2012.

This review summarises all orthognathic and related papers published between January 2011 and December 2012 in the British Journal of Oral and Maxillofacial Surgery (BJOMS). A total of 36 articles were published, a high proportion of which (78%) were full-length papers. The remainder consisted of short communications and technical notes. The topics included operative planning and postoperative outcomes, and there was a strong focus on distraction osteogenesis. There were fewer orthognathic articles published in BJOMS than articles on other subspecialties such as trauma or head and neck oncology. Only 8 (29%) of the full-length articles were prospective studies or randomised trials, which highlights a need for well-designed clinical studies in orthognathic research.

Symptomatic venous thromboembolism in orthognathic surgery and distraction osteogenesis: a retrospective cohort study of 4127 patients.

Venous thromboembolism is a common postoperative complication, and orthopaedic procedures are particularly at risk. We designed a retrospective, single centre, observational, cohort study of 4127 patients (mean (SD) age 27 (11) years) who had elective orthognathic operations or distraction osteogenesis between January 1970 and February 2012 at the VU University Medical Centre, Amsterdam, to investigate the incidence in this group over the 42-year period, 2 patients developed symptomatic venous thromboembolism (1 woman had a deep vein thrombosis (DVT) and 1 man had a DVT and pulmonary embolus) postoperatively. In relatively young patients with low to moderate risk factors and short hospital stay this type of operation is associated with a particularly low risk of developing thrombosis. It could be advisable to limit the use of thromboprophylaxis to patients at high risk or according to hospital guidelines.

Nationwide survey of surgically assisted rapid maxillary expansion.

We aimed to gather data on the current practice of surgically assisted rapid maxillary expansion (SARME) in the UK. Surveys were posted in the mail to all members of the British Association of Oral and Maxillofacial Surgeons (n=379) and 166 (44%) responded. In the previous year 69 responders (42%) had done at least one SARME operation. The technique used by individual surgeons may be more experience-based than evidence-based, which leads to considerable variation.

Guided growth for the treatment of moderate leg-length discrepancy.

The purpose of this study was to evaluate the effectiveness and complication rate of guided growth for the treatment of patients with a moderate leg-length discrepancy. The authors retrospectively reviewed all patients treated with guided growth for a moderate leg-length discrepancy at their institution between October 2004 and December 2010. Thirty-four patients met the inclusion criteria from an initial cohort of 105 patients. All patients were followed until screw removal or maturity occurred. Nine patients had a developmental leg-length discrepancy, and 25 had a congenital leg-length discrepancy. Average age was 12.6 years (range, 7-16 years). Average leg-length discrepancies, as measured on standing long-leg radiographs from the top of the pelvis, the top of the femoral heads, and the center of the ankle to the top of the femoral heads, were 22, 19, and 17 mm, respectively. Average discrepancies at screw removal or maturity were 13, 10, and 11 mm, respectively. Twenty of 33 patients had a leg-length discrepancy of less than 1 cm at maturity or screw removal. The leg-length discrepancy change in patients who underwent guided growth of the tibia was minimal. Leg-length discrepancies in patients who underwent guided growth of the femur or both the femur and the tibia changed by an average of 10 mm. One patient had a mechanical axis change greater than 1 zone, and 1 patient required treatment for angular deformity after being treated for a leg-length discrepancy. Guided growth is a safe and effective technique for treating moderate leg-length discrepancies.

Error analysis of a CAD/CAM method for unidirectional mandibular distraction osteogenesis in the treatment of hemifacial microsomia.

Our aim was to investigate the errors in a computer-aided design and manufacture (CAD/CAM) method of unidirectional mandibular distraction osteogenesis. Six patients with hemifacial microsomia were selected, and studied on computed tomographic (CT) scans taken at 3 time intervals: preoperatively, at the end of the latent period, and at the end of consolidation. The plan for mandibular distraction osteogeneisis was designed using CT-based 3-dimensional visible software. The osteotomy line and site of the drill were transferred to a rapid prototyping surgical guide. The osteotomy of the mandible and implantation of the distraction device were completed under guidance. The accuracy of the transferred surgical plan was confirmed by fusion of images after the latency period. The 3-dimensional superimposition of the preoperative simulation, and the postoperative actual models at the end of consolidation, showed that the mean (SD) error between the actual and the predicted height of the ramus was 0.6 (0.6) mm. The error between the actual and predicted intercondylar distance was 8.1 (2.1) mm. There was a significant difference in intercondylar distance between the simulated and actual groups (p=0.00024). The 3-dimensional CT-based planning system described in this paper was transferred precisely from the virtual plan to the real-time operation. The planning system also gave a precise prediction of the height of the ramus after mandibular distraction osteogenesis. However, because of the pull of the lateral pterygoid muscle and pseudarthrosis, the intercondylar distance decreased compared with the predicted value. These influencing factors should be considered when the planning system is refined.

Femoral bone transport by a monolateral external fixator with or without the use of intramedullary nail: a single-department retrospective study.

BACKGROUNDS: Treatment for bone defect remains a challenge for orthopedists. Bone transport gives an effective alternative, which can be performed with an external fixator alone or combined with an intramedullary nail. Each has its advantages and disadvantages. We present a retrospective study to find out the optimal choice by evaluating the outcomes of treatment for femoral bone defect with two methods. METHODS: Two groups of patients, the monolateral external fixator alone (group A, n = 13) and the monolateral external fixator combined with intramedullary nail (group B, n = 15), were compared. Duration of the external fixator, external fixator index, radiographic consolidation index, complication, and total cost for treatment was also recorded. A modified classification of the Association for the Study and Application of the Method of Ilizarov (ASAMI) was used to assess results in two groups of patients; another SF-36 health survey questionnaire was used to assess the life qualities patients of two groups. RESULTS: Healing was achieved in 13/13 and 13/15 of the two groups, respectively. The rates of complications were significantly higher in the group A. Two patients performed amputations because of persistent deep infections in group B. Statistically significant difference was found when comparing ASAMI scores and categories of the SF-36 health survey. CONCLUSIONS: Bone transport by monolateral external fixator with the use of intramedullary nail reduces the incidence of complication and the duration of external fixator time that give patients a better life quality in both physical and emotional. However, if chronic osteitis exists, bone transport should be treated with monolateral external fixator alone due to a lower rate of amputations.

Complications following surgically assisted rapid palatal expansion: a retrospective cohort study.

PURPOSE: To examine the prevalence of complications and characterize the associated clinical findings in patients undergoing surgically assisted rapid palatal expansion (SARPE). MATERIALS AND METHODS: A retrospective evaluation was conducted of all patients who underwent SARPE from January 2004 through December 2008 at Kaiser Permanente Oakland Medical Center. Medical records were abstracted, and demographic factors and relevant comorbidities were identified. Clinical features of patients with complications (surgical and/or dental) after SARPE were characterized. RESULTS: One hundred thirty-one patients comprised the study sample and 11 patients were excluded. Of the remaining 120 patients (median age, 29.5 yrs; interquartile range, 22.0 to 39.0 yrs), 51.7% were women, 41 developed at least 1 complication, 33 had surgical complications, 18 had dental and/or periodontal problems, and 10 developed both surgical and dental or periodontal problems. Asymmetric and/or inadequate expansion was the most frequent surgical complication, found in 13.3% of the study cohort, and gingival recession (8.3%) was the most common dental complication. Two patients developed catastrophic periodontal bone defects resulting in loss of the central incisors; these patients had eccentric interdental osteotomies that caused separation of the bone from the root surface of the central incisors followed by postoperative osteotomy site infections. CONCLUSIONS: Overall, the present findings suggest that, although major complications after SARPE were rare, asymmetric or inadequate expansion and dental and/or periodontal problems primarily involving the central incisors accounted for most complications. Future prospective and long-term follow-up studies are needed to identify individual risk factors that may predispose patients to adverse outcomes after SARPE.

Limb angular deformity correction using Dyna-ATC: surgical technique, calculation method, and clinical outcome.

PURPOSE: Dyna-ATC is a unilateral external fixator with angulator, lengthener, and translator, which allows for angular correction and compensation of the secondary displacement during angular correction. The purpose of this study is to introduce surgical technique and calculation methods and to evaluate the clinical outcome of angular deformity correction using Dyna-ATC. MATERIALS AND METHODS: The amounts of secondary displacement were calculated with the distances between axis of correction of angulation, Center of Rotational Angulation, and osteotomy and the amount of angular deformity. The rate of angular correction was determined to distract the corticotomy at 1 mm/day. Clinical and radiographic evaluation was performed on 13 patients who underwent deformity correction using Dyna-ATC. There were 8 proximal tibia vara, 1 tibia valga, 2 varus and 4 valgus deformities on distal femur. One patient underwent pelvic support femoral reconstruction. Concomitant lengthening was combined in all femur cases. Mean age at surgery was 17.5 years (7 to 64). RESULTS: All but one achieved bony healing and normal alignment with the index procedure. Mean mechanical axis deviation improved from 31.9 mm to 3.0 mm. The average amount of angular correction was 11.0° on tibiae and 10.0° on femora. The average length gain on femora was 6.4 cm, and the healing index averaged to 1.1 mo/cm. One patient underwent quadricepsplasty and one patient had three augmentation surgeries due to poor new bone formation. CONCLUSION: We believe that Dyna-ATC is a useful alternative to bulky ring fixators for selective patients with angular deformity less than 30 degrees in the coronal plane around the knee joint.