Distractor Placement Research Articles

Distractor position and distraction amplitude in fronto-facial monobloc advancement : A case series

Fronto-facial monobloc advancement with internal distraction (FFMBA) is a central procedure in the management of faciocraniosynostoses. In techniques with internal distraction, two sets of devices are generally positioned: bilateral fronto-orbital and temporo-zygomatic distractors, using a temporal tongue and groove osteotomy design. It is believed that distractors must be positioned as parallel as possible in the horizontal and sagittal planes to avoid mechanical conflicts between the sliding bone fragments of the tongue and groove during distraction, and thus optimize the advancement amplitude. Several approaches involving surgical planification and guides for distractor positioning have thus been proposed to monitor distractor placement.To explore the need for surgical planification in distractor placement, the parallelism of the position of the 4 distractors was assessed in 19 FFMBA procedures and we correlated a set of 10 distractor angles with the degree of advancement.We report that the horizontal cut of the tongue and groove can be used as a landmark for the positioning of the lower, temporo-zygomatic, distractor in fronto-facial monobloc advancement. Other parameters (relative position of the two homolateral and the two contralateral distractors and the orientations of the vertical and horizontal cuts of the tongue and groove) do not interfere with distraction, other things being equal.Our results indicate that distractor orientation is not a critical issue in fronto-facial monobloc advancement when devices are positioned as parallel as possible based on visual monitoring.

Computerized Surgical Planning for Mandibular Distraction Osteogenesis.

Mandibular distraction osteogenesis is a technically challenging procedure due to complex mandibular anatomy, especially in the treatment of Pierre-Robin Sequence due to variable bone thickness in the infant mandible and the presence of tooth buds. Computerized surgical planning (CSP) simplifies the procedure by preoperatively visualizing critical structures, producing cutting guides, and planning distractor placement. This paper describes the process of using CSP to plan mandibular distraction osteogenesis, including discussion of recent advances in the use of custom distractors.

Posterior Vault Distraction in the Acute Setting.

Posterior vault distraction osteogenesis (PVDO) has been shown to resolve acute intracranial hypertension (AIH) while carrying an acceptable perioperative morbidity profile. PVDO has been associated with symptomatic improvement and fewer surgeries in those requiring ventriculoperitoneal shunts. The authors' experience using PVDO as an acute intervention is presented, demonstrating its safety and efficacy for management of AIH. Four cases of children with craniosynostosis that underwent PVDO in the acute setting are outlined. All patients presented with papilledema and symptoms of AIH. One patient with slit ventricle syndrome (SVS) presented with a nonfunctioning shunt following multiple shunt revisions. No intraoperative complications during distractor placement or removal were reported. Distraction protocol for all patients began on postoperative day 1 at 1-2 mm per day, resulting in an average total distraction of 30.25 mm. For the 3 cases with no shunt, the average length of stay was 7 days. As part of the planned treatment course, the patient with SVS required externalization of the shunt during distraction followed by early distractor removal and planned shunt replacement. One case of surgical site infection (in an immunocompromised patient) required premature distractor removal during the consolidation period. Computed tomography (CT) in all patients indicated increased intracranial volume following distraction, and symptomatic improvement was reported. Six-month follow-up showed resolution of papilledema in all patients. The authors' experience using PVDO in the acute setting is reported, alongside a review of current literature, in order to provide supporting evidence for the efficacy of PVDO as a tool for resolving AIH.

The Role of Virtual Surgical Planning in Surgery for Complex Craniosynostosis.

Virtual surgical planning (VSP) decreases reliance on intraoperative subjective assessment of aesthetic and functional outcomes in craniofacial surgery. Here, we describe our experience of using VSP for complex craniosynostosis surgery to inform preoperative decision making and optimize postoperative outcomes. Chart review was performed for children treated with craniosynostosis at our institution from 2015 to 2021. Eight VSP maneuvers were defined and assigned to each patient when applicable: (1) complex cranioplasty: combined autologous and synthetic; (2) autologous cranioplasty; (3) synthetic cranioplasty; (4) vector analysis and distractor placement; (5) complex osteotomies; (6) multilayered intraoperative plans; (7) volume analysis; and (8) communication with parents. Outcomes between VSP and non-VSP cohorts were compared. Of 166 total cases, 32 were considered complex, defined by multisutural craniosynostosis, syndromic craniosynostosis, or revision status. Of these complex cases, 20 underwent VSP and 12 did not. There was no difference in mean operative time between the VSP and non-VSP groups (541 versus 532 min, P = 0.82) or in unexpected return to operating room (10.5% versus 8.3%, P = 0.84). VSP was most often used to communicate the surgical plan with parents (90%) and plan complex osteotomies (85%). In this cohort, VSP was most often used to communicate the surgical plan with families and plan complex osteotomies. Our results indicate that VSP may improve intraoperative efficiency and safety for complex craniosynostosis surgery. This tool can be considered a useful adjunct to plan and guide intraoperative decisions in complex cases, reducing variability and guiding parental expectations.

Pharyngeal Airway Changes Following Mandibular Distraction Osteogenesis as Evaluated with Laryngoscopy.

Mandibular distraction osteogenesis (MDO) may improve airway grade in patients with Robin Sequence (RS), but little is known about the response of the oropharyngeal airway to the distraction process in cases of tongue base obstruction (TBAO). This study used drug-induced sleep endoscopy (DISE) to evaluate the impact of MDO on the oropharynx. RS patients with severe obstructive sleep apnea (OSA) were prospectively enrolled, and underwent DISE prior to MDO, and at the time of distractor removal. Laryngoscopy views, glossoptosis degree, polysomnography (PSG) results, oxygen saturations and airway measurements were compared pre- and post-MDO. Twenty patients met inclusion criteria. At the time of distractor placement, a grade II laryngoscopic view was most frequently observed (63%), and one patient (5%) had a grade I view. Median obstructive apnea hypopnea index (OAHI) improved after MDO (49.1 [30.2-74.0] to 9.1, [3.9-18.0], p ≤ .001). Median oxygen saturation nadir also improved (preoperative 69% [60-76] to 85% [82-91], p ≤ .001). At distractor removal, mean laryngoscopic view improved (p ≤ .002) with no views that were grade 3 or higher. Median intraoperative oropharyngeal width improved, (3.1 mm [2.8-4.4] to 6.0 mm [4.4-6.8], p ≤ .021), as did median cephalometric anteroposterior oropharyngeal width (3.5 mm [2.7-4.1] to 6.3 mm [5.6-8.2], p ≤ .002). Following MDO, RS patients with TBAO have an approximate doubling of oropharyngeal width and an improvement in laryngoscopic grade. These findings likely contribute to improved oxygenation, OAHI and ease of intubation.

Isolated Frontosphenoidal Synostosis: Early Clinical Management of a Rare Condition With Distraction Osteogenesis

Isolated frontosphenoidal synostosis (FSS) is an extremely rare pathology in which premature fusion of the frontal and sphenoid bones produces asymmetry of the forehead in a newborn or young child. If left untreated, these children may suffer significant esthetic and neurologic symptoms. Therefore, surgery is time-sensitive and necessary for correction. This report details the case of a male infant who presented to clinic at 3 months of age with unilateral, isolated FSS. Clinical features of this patient included an asymmetric forehead with flattening of the right frontal temporal area, indentation of the right temporal sphenoid area, and inferiorly displaced right orbit. Previous reports have been in older patients who were treated with open fronto-orbital advancement. With the patient’s early presentation, the primary surgical approach deployed here included anterior cranial vault remodeling with right distractor placement and fronto-orbital osteotomy. Four months following the procedure, the patient returned with increased right-sided hypoglobus and enophthalmos. CT imaging revealed a pseudomeningocele, secondary to a dural tear. Consequently, the 7-month-old underwent a second surgery, which included fronto-orbital advancement reconstruction. The child remains stable with improved forehead symmetry at 11 months of age. Due to the rare nature of FSS, treatment options are limited and traditional in their approach. This report aims to contribute additional clinical insights and treatment guidance to the growing body of literature surrounding FSS.

Feasibility of a Robot-Assisted Surgical Navigation System for Mandibular Distraction Osteogenesis in Hemifacial Microsomia: A Model Experiment.

This study aimed to investigate the feasibility and accuracy of osteotomy and distractor placement using a robotic navigation system in a model surgical experiment of mandibular distraction osteogenesis for hemifacial microsomia. Imaging data from 5 patients with Pruzansky-Kaban type II (IIa: 4; IIb: 1) mandibular deformities were used to print 3D models for simulated mandibular distraction osteogenesis. In the experimental group, a robot-assisted surgical navigation system was used to perform the surgery under robotic guidance following registration, according to the preoperative design. Conventional surgery was performed in the control group, in which the operation was based on intraoperative estimations of the preoperative design by experienced surgeons. The accuracies of the osteotomy and distractor placement were assessed based on distance and angular error. Osteotomy accuracy was higher in the experimental group than in the control group, and the distance error ( t =9.311, P <0.001) and angular error ( t =5.385, P =0.001) were significantly reduced. The accuracy of distractor placement was also significantly higher in the experimental group, while the distance error ( t =3.048, P =0.016) and angular error ( t =3.524, P =0.024) were significantly reduced. The present results highlight the feasibility of robot-assisted distraction osteogenesis combined with electromagnetic navigation for improved surgical precision in clinical settings.

Radiographic Analysis of Pedicle Screw Retractor-Assisted Transforaminal Lumbar Interbody Fusion for Single-Segment Spondylolisthesis in Adults: A Retrospective Study and Technical Note.

ObjectivesThe objective of this study was to introduce a retractor that can be temporarily installed on unilateral pedicle screws to achieve distraction‐reduction and nerve root protection, and to analyze the efficacy and safety of retractor‐assisted transforaminal lumbar interbody fusion (TLIF) in the treatment of lumbar spondylolisthesis.MethodsThis was a retrospective study of 125 patients who underwent retractor‐assisted TLIF for single‐segment spondylolisthesis from November 2017 to February 2021. Based on morphology, patients were divided into degenerative (N = 66) and isthmic groups (N = 59). Differences in demographics and preoperative characteristics between the groups were analyzed using the independent samples t‐test and χ 2 test. Changes in radiographic parameters (disc height, foramen height, spondylolisthesis degree, slippage length, and segmental lordosis) before and after surgery were compared using the paired samples t‐test. Logistic regression analysis was performed to analyze the relationship between facet joint angle (FJA) and degenerative lumbar spondylolisthesis (DLS).ResultsUnilateral screw retractor‐assisted TLIF significantly corrected spondylolisthesis and improved disc height and segmental lordosis (p < 0.05). There was no significant difference in foramen height between the two sides before and after operation (pre: 15.81 ± 3.58 mm vs 15.69 ± 3.68 mm, p = 0.599; post: 18.65 ± 2.31 mm vs 18.74 ± 2.26 mm, p = 0.516). The degree of spondylolisthesis in the DLS group before surgery was significantly lower than that in the isthmic spondylolisthesis group (17.70 ± 5.62% vs 25.18 ± 9.73%, p < 0.001), whereas a similar degree of correction could be achieved after surgery (5.91 ± 3.12% vs 7.16 ± 5.69%, p = 0.135). FJAs from L3/4 to L5/S1 were significantly smaller in patients with DLS than those in with isthmic spondylolisthesis (p < 0.05). Patients with facet sagittalization were more likely to have DLS (β: −0.101, odds ratio [OR]:0.904, 95% confidence interval [CI]: 0.874–0.934, p < 0.001), while the cut‐off FJA of L4/5 for predicting L4 spondylolisthesis was 53.19.ConclusionsPedicle screw retractor‐assisted TLIF is effective and safe in treating both degenerative and isthmic lumbar spondylolisthesis. The unilateral retractor has the capacity to maintain the disc height achieved by paddle distractors, which optimizes the nerve protection and distractor placement. Patients with an FJA on L4/5 <53.19 were more likely to have DLS.

Postoperative Changes in the Upper Airway Following Mandibular Distraction Osteogenesis in Pediatric Hemifacial Microsomia.

Patients with hemifacial microsomia (HFM) may undergo unilateral mandibular distraction osteogenesis (MDO) before skeletal maturity in an effort to improve facial symmetry. Mandibular distraction osteogenesis's effect on airway volumes have been studied in the past, though to our knowledge, none have accounted for the effect of head and neck posture on airway morphology. This study aimed to tackle this shortcoming, using imaging to analyze the upper airway of patients with HFM before and after surgical intervention with MDO. The authors retrospectively reviewed patients with a diagnosis of unilateral HFM whom underwent unilateral MDO with an oblique vector at age 4 to 14 years at a single institution from 2004 to 2019. Patients with pre- and post-MDO three-dimensional computed tomography scans of the upper airway within 12 months of distractor placement and removal, respectively, were included. Head and neck postures were determined by craniocervical, pitch, roll, and yaw angles. Pre- and post-operative pharyngeal airway volumes, pharyngeal surface area, minimum retropalatal cross-sectional areas (RP CSA) and retroglossal (RG) CSA and associated anteroposterior distances were measured using Mimics 22.0 (Materialise; Leuven, Belgium). Comparison was done using Kruskal-Wallis tests and linear mixed-effects models controlling for head and neck postures. Ten patients met inclusion criteria. Mean age at pre-distractor placement computed tomography scan was 99 ± 35 months, and mean duration between pre- and post-surgery scans was 220 ± 90 days. Head and neck posture were found to be significant predictors of all airway dimensions. After controlling for significant factors with fixed effects linear modeling, surface area was found to be significantly smaller in patients after MDO by 189.48 mm2 (F[10.8] = -3.47, P = 0.0053), compared to their preoperative measurements. Surgery was not a significant predictor of changes in airway volume (F[11.6] = 0.52, P = 0.61), minimum RP CSA (F[12.2] = -0.64, P = 0.53), minimum RG CSA (F[12.6] = -1.64, P = 0.13), RP anteroposterior distance (F[14.0] = 0.30, P = 0.77), or RG anteroposterior distance (F[20.0] = -0.04, P = 0.97). Oblique vector MDO in patients with HFM is associated only with statistically significant changes in the surface area of the upper airway, and is not associated with statistically significant changes in dimensions like volume, CSA, or anteroposterior dimension. This is an important finding, as it may guide discussions surrounding risk/benefit ratio for MDO in childhood.

Polysomnography in the Early Consolidation Phase of Mandibular Distraction as a Tool to Identify Residual Tongue-Based Airway Obstruction and Need for Further Distraction: A Follow-Up Study

Background: The objective of this study was to analyze and report our experience with using polysomnography (PSG) during the early consolidation phase of mandibular distraction osteogenesis (MDO) in patients with Pierre Robin Sequence and associated tongue-based airway obstruction with management decisions informed by the results. The secondary objective was to determine whether pre-operative PSG can predict which patients will have persistent obstructive sleep apnea (OSA) and require additional distraction. Methods: A single-surgeon, retrospective review was performed of all patients who underwent MDO for treatment of tongue-based airway obstruction over an 11-year period. Pre-operative and post-distraction 16-channel overnight bedside PSG was performed on all patients and scored according to the AASM Scoring Manual. Patients who demonstrated persistent OSA underwent further distraction and were reevaluated by PSG after final distraction length was achieved. Results: Pre-operative and post-distraction PSG was obtained and available for analysis in 37 patients. Apnea-Hypopnea Index (AHI) improved from 45.85 ± 34.41 to 9.73 ± 10.85 ( P &lt; .001). There was evidence for persistent, severe OSA in 14 patients (38%) and persistent, moderate OSA in 6 patients (16%) in the early consolidation phase of MDO. Nine of these patients underwent additional distraction and demonstrated symptomatic resolution and quantitative improvement in all PSG measures. The group of patients that underwent additional distraction had significantly more severe baseline OSA as defined by preoperative AHI, oxygen desaturation index (ODI), and percentage of time spent below 90% SpO2. There was no significant difference in patient characteristics or pre-operative symptoms between the 2 groups. Conclusions: PSG can be performed at the bedside at the end of the distraction phase of MDO to assess for residual airway obstruction and inform the need for further distraction. Pre-operative PSG measures can help predict the need for further distraction and aid in operative planning and distractor placement.

Accuracy of Virtually Planned Maxillary Distraction in Cleft Patients - An Evaluative Study.

Introduction:Maxillary distraction may be used to treat severe maxillary hypoplasia in cleft lip and palate (CLP) patients. Three-dimensional (3D) planning has been shown to increase the accuracy of distraction and reduce operative time and complications. The aim of the study was to measure the accuracy of internal maxillary distraction after 3D planning in CLP patients, to add evidence to validate the virtual osteotomy and distraction procedure.Materials and Methods:Eleven CLP patients with severe maxillary hypoplasia underwent maxillary distraction using internal distractors. Virtual planning was used to design the osteotomies, the distractor position, and the distraction vector. Cutting and positioning guides transferred this information to the surgical procedure. Four to six month postoperative computed tomography-scan was done before distractor removal; anatomical reference points were compared to the virtual planning to determine accuracy.Results:A high accuracy (point dislocation <1.5 mm) was found in 90% of the points of the surface of the maxilla; the majority of the zygomatic screws were placed within a distance of 0.8–1 mm from their planned position.Discussion:The high accuracy achieved through virtual planning promotes optimal distractor placement; a customized distraction vector has a direct effect on the final position of the maxilla.

Use of Tongs as Occlusion Plane Guide for Midface Distractor Placement

Use of Tongs as Occlusion Plane Guide for Midface Distractor Placement

Evaluation of a self-retaining distractor for hip joint arthroscopy in toy breed dogs

BackgroundHip arthroscopy has become a viable option over the last few years for small animal orthopedic diseases, including hip dysplasia, osteoarthritis, and joint evaluation. However, the narrow joint spaces make it difficult to manipulate the instrument, and depth of tissues make it difficult to distract the joint space. In addition, it is very difficult to maintain consistent distraction over time with a manual distraction due to hand fatigue. To overcome these difficulties, distractors are used in human medicine to improve safety and accuracy of arthroscopy. Therefore, in this study, distractor devices were applied to hip joints in small toy breed dogs to evaluate their technical efficacy. Potential iatrogenic neurovascular and articular damage were also evaluated by comparing two techniques for performing hip joint arthroscopy: the self-retaining distractor and external manipulation.ResultsThe mean ± SD of the joint distraction distance was 8.88 ± 3.54 mm in the self-retaining distraction group and 2.37 ± 0.82 mm in the manual traction group. As the joint space increased, surgeons could more easily place an arthroscopy portal and more comfortably manipulate the instrument with a distractor device. Furthermore, the acetabular cartilage damage (p = 0.004) was significantly greater in the external manipulation group, but articular damage to the femoral head (p = 0.940) was similar in both groups.ConclusionThe results of this study revealed that use of a distractor device can be a viable option for performing hip arthroscopy in small animals. The device significantly improved the surgeon’s performance without surgical assistance, and it reduced iatrogenic cartilage damage compared with manual traction. Further study is needed to quantify neurapraxia associated with distractor placement.

Persistent Opioid Use Among Children, Adolescents, and Young Adults After Common Cleft Operations.

Surgical care represents an important source of opioid prescribing and chronic use, but rates of prolonged opioid use following pediatric procedures remain unclear. The authors describe the rates and risk factors for new persistent opioid use in patients after common cleft operations. The authors examined claims from the Truven Marketscan databases from January 1, 2010 to December 31, 2014. The authors included opioid-naive patients ages 8 to 25, who underwent 1 of 10 cleft-related procedures. Patients were considered opioid-naïve if they had no opioid prescription fills in the 11 months prior to the perioperative period. The authors obtained a random sample of age-matched, nonsurgical patients from the same dataset to be used as a control group. Included cleft patients had no procedural codes in the 6 months following surgery. All included patients filled an opioid prescription during the perioperative period, defined as 30 days before and 14 days after surgery. The primary outcome was new persistent opioid use, which is defined as continued opioid prescription fills between 90 and 180 days after the procedure. This cohort included 2039 cleft patients and 2100 control patients. The incidence of new persistent opioid use following surgery was 4.4% and 0.1% in the control group. Higher odds of opioid use 3 months beyond surgery were associated with distractor placement (OR 5.34, CI 2.00-14.24, P = 0.001). Increasing age (OR 1.11, CI 1.04-1.17, P = 0.001) and presence of a gastrointestinal comorbidity (OR 7.37, CI 1.49-36.54, P = 0.014) were also associated with new persistent use. New persistent opioid use occurs after cleft-related procedures and could lead to chronic use in children, adolescents, and young adults.

Asymmetries in Distractibility: Left Distractors Improve Reaction Time Performance

Research using the irrelevant-distractor paradigm shows perceptual load influences distractibility, such that distractors are more likely to be processed and decrease reaction times during low perceptual load. In contrast, under high load, attentional resources are limited, and the likelihood of distractibility is decreased. We manipulated distractor placement to determine whether location differentially influenced distractibility. During low load, reaction times were increased equally for all distractor locations. Under high load, left distractors speeded reaction times significantly more than right distractors. We suggest two potential explanations: (1) the central focus of attention was sufficiently large to encapsulate both the distractor and the visual array during low perceptual load, leading to increased distraction—during high load, attention was split across the two visual stimuli, allowing the distractors and array to be processed independently; (2) superior executive control for stimuli in the left visual field allowed participants to ‘catch and release’ left distractors more efficiently, ultimately decreasing distraction and providing a performance benefit. Our findings represent an intriguing development in relation to visual asymmetries in distractibility.

The role of stimulus comparison in animal perceptual learning: Effects of a distractor placement.

Research on perceptual learning shows that the way stimuli are presented leads to different outcomes. The intermixed/blocked (I/B) effect is one of these outcomes, and different mechanisms have been proposed to explain it. In human research, it seems that comparison between stimuli is important, and the placement of a distractor between the pre-exposed stimuli interferes with the effect. Results from animal research are usually interpreted in different terms because the type of procedure normally used in animal perceptual learning does not favour comparison. In our experiments, we explore the possibility that a distractor placed between the to-be-discriminated stimuli may interfere with the perceptual learning process in rats. In Experiment 1, two flavoured solutions are presented in an I/B fashion, with a short time lapse between them to favour comparison, showing the typical I/B effect. In Experiment 2, we introduced a distractor in between the solutions, abolishing this effect. Experiment 3 further replicates this by comparing two intermixed groups with or without distractor. The results replicate the findings from human research, suggesting that comparison also plays an important role in animal perceptual learning.

Experiences in Performing Posterior Calvarial Distraction.

The use of posterior calvarial distraction (PCD) for the management of craniosynostosis is well recognized. The advantages of using this technique include increased cranial volume, decreased intracranial pressure, relief of posterior fossa crowding, improved cerebrospinal fluid (CSF) circulation at the cranio-cervical junction with cessation, and possible resolution of syrinx.The authors retrospectively review their first 50 patients who have undergone PCD under the senior author's care in our unit.The demographics, diagnoses, intraoperative approach with techniques in distractor placement and outcomes of each patient were obtained through an electronic craniofacial database and written patient records. Analysis of complication rates (bleeding, distraction problems, CSF leaks, and infection) was included.A total of 31 boys and 19 girls underwent the procedure between October 2006 and September 2015 with a median age was 17.7 months (range 4 months to 19 years). Of those 50 children, 34 of the cohort were proven to be syndromic by genetic testing.The median length of inpatient stay was 9.4 days (range 3-43 days). Average distraction distance was 24 mm.Complications including CSF leaks, bleeding, distractor problems, and severe complications (recorded in 3 patients) are discussed. Our overall complication rate was 50%.Favorable outcomes included resolution of Chiari, syrinx, and raised intracranial pressure in the majority of patients where distraction was successful.The authors recommend that PCD should be considered the primary treatment for increasing calvarial volume. The authors discuss our experiences and technical innovations over the past decade.

Simulation-guided navigation for vector control in pediatric mandibular distraction osteogenesis

AimNavigation technology has given surgeons the capacity to know precisely where their instruments are during surgery, and simulation-guided navigation is a surgical method which is based on the use of navigation technology linked to 3D virtual surgery simulation. The aim of the present study was to evaluate the absolute accuracy of simulation-guided navigation as an aid to reproduce the planned position of the distraction device vector in pediatric mandibular distraction osteogenesis. Materials and methodsWe retrospectively evaluated seven patients affected by unilateral (3 pts.) or bilateral (4 pts.) mandibular hypoplasia and treated with this method between 2012 and 2014 at the Maxillofacial Surgery Unit of the University of Bologna, Italy. All patients were enrolled for mandibular distraction using internal unidirectional devices (11 distraction devices implanted overall). Patients were studied through a complete three-dimensional workflow, which led to obtaining a virtual reconstruction of the facial bones and the simulation of the distraction device positioning using a specific experimental software. The surgical planning was loaded on the navigation system and the distraction device was placed following the virtual plan, which is displayed on the navigation system as a guide and tracked with the navigation instruments. ResultsWe analyzed the outcome comparing the recorded three-dimensional coordinates of the achieved distractor position and the three-dimensional coordinates of the planned distractor position. Among the eleven placed distractors, we found a mean angular error of 3.74° ± 3.30° on the axial axis (yaw) and of 6.27° ± 5.32° on the sagittal axis (pitch), while median angular errors are 3.72° on the axial axis (yaw) and 4.08° on the sagittal axis (pitch). ConclusionOur preliminary experience seems to support that simulation-guided navigation for vector control in mandibular distraction osteogenesis could be a useful procedure for reproducing the virtually planned outcome. Nevertheless, our results cannot be considered completely satisfactory. There is a lot of room to improve accuracy and errors seem to depend mainly on the soft tissues interference during distractor placement.

Modified condylar distraction osteogenesis via single preauricular incision for treatment of temporomandibular joint ankylosis.

Temporomandibular joint (TMJ) ankylosis with facial asymmetry is still controversial to deal with. This study describes a modified condylar distraction osteogenesis protocol via preauricular approach for the treatment of this condition. From 2006 to 2013, 18 patients with TMJ ankylosis were enrolled. The Wuhan TMJ Ankylosis treatment protocol includes as follows: (1) preauricular approach is the only surgical access; (2) TMJ arthroplasty is used to recontour the condylar head, and the vertical height of condyle is maintained; (3) distractor placement with distractor port exiting via preauricular incision; (4) distraction after 5 to 7 days of latency period with 0.5 mm twice daily; and (5) distractor removal after 3-month consolidation through preauricular incision. All patients had clinical follow-up and detailed examination. All patients had satisfactory results postoperatively. The mean (range) mouth opening increased from 7.1 (0-18) to 32.1 (28-43) mm during 37 (6-81) months of follow-up period (P < 0.01). Facial asymmetry was corrected in all patients, and all patients had minimal postoperative scar perception of the preauricular incision. The Wuhan TMJ ankylosis protocol provides a safe and effective treatment alternative in managing TMJ ankylosis, especially in young women who are anxious about perceptive extraoral scar.

Microdensitometric and microarchitectural alterations in irradiated mandibular fracture repair.

Head and neck cancer most often requires a multimodality approach to treatment that includes the use of radiotherapy. Unfortunately, radiation treatment can cause significant locoregional adverse effects with the particularly debilitating sequelae of late pathologic fracture. We aimed to define comprehensive metrics that will allow us to evaluate the efficacy of therapies aimed at assuaging the damaging effects of radiation on fracture healing.Six male rats (XRT/Fx) received a 36-Gy preoperative radiation dose delivered in 10 fractions over 10 days to their left hemimandible, whereas 6 other rats were not irradiated (Fx). After a recovery period, a unilateral osteotomy was performed with external distractor placement set to a 2.1-mm fracture gap on all the animals. Following a 28-day consolidation interval, mandibles were harvested and scanned via micro-computed tomography. Radiomorphometrics were extracted and analyzed with significance at P < 0.05.A quantifiable decrease in bone volume fraction (73.9% vs 78.6%; P < 0.05) was observed in XRT/Fx compared with Fx, without significant change in bone mineral density. Microarchitectural metrics were significantly altered in XRT/Fx compared with Fx, specifically trabecular thickness (0.37 vs 0.30 µm; P = 0.01), trabecular number (2.18 vs 2.45 N/mm; P = 0.04), and bone surface-bone volume ratio (5.50 vs 6.70; P = 0.01).We found that the irradiated and fractured bone demonstrated a significant diminution in bone quality and strength. We have established predictable and reliable radiographic measures that quantitatively demonstrate the degradative effects of radiation on fracture repair. We can now utilize these comprehensive metrics to evaluate the benefits of therapeutic interventions to remediate the damaging effects of radiation on fracture healing.