Distraction Rate Research Articles

S7B-04 SESSION 7B: HFM ROBIN - PART II RATE AND RISK FACTORS FOR REPEATED MANDIBULAR DISTRACTION OSTEOGENESIS IN INFANT PATIENTS WITH TONGUE BASED AIRWAY OBSTRUCTION

Introduction: Mandibular distraction osteogenesis (MDO) has demonstrated efficacy for tongue-based airway obstruction in infant Pierre Robin Sequence (PRS). The purpose of this study is to identify risk factors for patients who require repeat distraction after MDO in early infancy for PRS. Methods: Consecutive patients who underwent MDO from 2004 to 2018 at a single institution were retrospectively reviewed. Patient characteristics including age at initial MDO, comorbidities, polysomnographic parameters, and distraction data were collected. Patients whose initial surgery was before 2 months of age were identified and divided into cohorts: single versus repeat distraction. Results: 103 patients were identified during the study period - 95 had a single distraction procedure and 8 required repeat distraction. Indications for repeat distraction were recurrent airway obstruction (6), failure to extubate (1), and persistent micrognathia (1). There was no difference in age or weight at initial distraction, duration of distraction, or distraction length between single and repeat distraction groups. Overall, average AHI was 39.9 pre-operatively and 10.1 post-operatively; neither varied between groups. Genetic anomalies and syndromic diagnoses were more common in the repeat distraction group (75.0% vs. 40.0% single distraction, p=0.06). More patients had laryngomalacia in the repeat distraction group (75.0% vs. 33.7% single distraction, p=0.02). Conclusion: MDO has been accepted as efficacious in PRS but the rate of repeat distraction has not been described. In this study 7.8% of infants required redistraction and the identified risk factors were genetic anomaly or syndromic diagnosis, pre-operative laryngomalacia, or recurrent airway obstruction.

SYM9.9E Necker Experience of Frontofacial Monobloc Advancement with Distraction (FFMBA): 145 cases in faciocraniosynostotic children

Introduction: in faciocraniosynostotic children, simultaneous correction of raised intracranial pressure, frontal retrusion, exorbitism, and facial retrusion causing sleep apnea syndrome can be achieved by frontofacial monobloc advancement. Methods: Since year 2000, 145 children aged between 9 months and 17 years were operated on by the same surgeon (EA) of a frontofacial Monobloc osteotomy. Frontal bone elevation was performed in all cases. Main group of 138 patients underwent insertion of 4 internal distractors (KLS Martin, Arnaud and Marchac distractors). A subgroup of 7 patients aged under 15 months underwent postoperative external traction (3kg) applied to a zygomatic transfacial pin (K-wire 2mm in diameter). In the subgroup of young patients, a prolongated sedation was necessary during one week. In all primary patients (never operated of a frontoorbital advancement before), transposition periosteal flaps were used to seal the anterior fossa.A systematic simple protocol of lumbar puncture during 3 days was used in case of suspicion of postoperative CSF leak. In a subgroup of 109 patients who were prospectively evaluated for respiratory outcome, 44% had a systematical removal of adenoids and tonsils prior to Monobloc. Results: in 95% of patients exorbitism was corrected. Class I occlusion was obtained only in 75% of the cases at the end of distraction. The mean OSAS measured on AHI was reduced from 19.1 (+/-17.2) to a mean 12.5 (+/-13.6). But, only the patients in whom adenoids and tonsils were removed preoperatively benefited frankly from the Monobloc.The rate of major infections was 2% (3 out of 145) mostly in secondary patients. The rate of mortality was 1,3 % (2 patients out of 145): one was due to an untreated preoperative Chiari, the other to very severe venous malformations (both these complications occurred at the beginning of our experience). Minor complications included frequently contaminations of internal distractors (30%), and CSF leaks requiring temporary treatment in 8%. The use of transfacial pin was detrimental to tooth buds but helped correction of airways obstruction in severe patients around one year of age. Postoperative OSAS was significantly lower when premonobloc ENT surgery was performed (tonsils and adenoids) Conclusions: Recommendations for surgical management of FFMBA include the following: - Preoperative screening including CT scan, MRI with venous analysis, polysomnography and ophthalmologic examination. - Preliminary systematic ENT removal of tonsils and adenoids (if significally present). - Preliminary management of Chiari by posterior vault distraction associated to foramen magnum decompression if necessary - Prefer primary cases for FFMBA allowing systematic closure of anterior cranial fossa by bilateral anteriorly based pericranial flaps (those flaps rarely available in previously operated patients)- This step necessitates frontal bone elevation - Use 4 internal distractors with consolidation time of 4–6 months. - Sedation of 2–4 days useful in the immediate post-operative period. - Slow distraction rate to 0,5mm/day starting at day 3 until completion (20–25 mm). - Obtain overcorrection at orbital level, and at dental level if possible. - In the very young and very severe, a very early FFMBA could be performed with adjunction of transfacial pin and external traction during one week. - Postoperatively, reeducate mouth opening to prevent trismus

Distal tibial distraction osteogenesis\u2014an alternative approach to addressing limb length discrepancy with concurrent hindfoot and ankle reconstruction

BackgroundLimb length discrepancy (LLD) in the setting of concurrent hindfoot and ankle deformity poses an added level of complexity to the reconstructive surgeon. Regardless of etiology, a clinically significant LLD poses additional challenges without a forthright and validated solution. The purpose of the current study is to determine whether reconstructive hindfoot and ankle surgery with concurrent lengthening through a distal tibial corticotomy is comparable to other treatment alternatives in the literature.Patients and methodsA retrospective review of hindfoot and ankle deformity correction utilizing Ilizarov circular external fixation with concurrent distal tibial distraction osteogenesis from July 2009 to September 2014 was conducted.ResultsThis study included 19 patients with a mean age of 47.47 ± 13.36 years with a mean follow up of 576.13 ± 341.89 days. The mean preoperative LLD was 2.70 ± 1.22 cm and the mean operatively induced LLD was 2.53 ± 0.59 cm. The mean latency period was 9.33 ± 3.47 days and distraction rate was 0.55 ± 0.16 mm/day. The mean distraction length was 2.14 ± 0.83 cm and mean duration of external fixation was 146.42 ± 58.69 days. The time to union of all hindfoot and ankle fusions was 121.00 ± 25.66 days with an overall fusion rate of 85.71%.ConclusionsThe successful treatment of hindfoot and ankle deformity correction in the setting of LLD using the technique of a distal tibial corticotomy and distraction osteogenesis is reported and illustrates an additional treatment technique with comparable measured outcomes to those previously described. We urge that each patient presentation be evaluated with consideration of all described approaches and associated literature to determine the current best reconstructive approach as future studies may validate or replace the accepted options at present.

Effectiveness of a Piezoelectric-Assisted Distraction Osteogenesis Procedure for the Treatment of Ankylosed Permanent Front Teeth.

A common complication of tooth replantation after traumatic avulsion is tooth ankylosis causing dental malpositioning, partial loss of function, tipping of adjacent teeth and worsening of aesthetics. The aim of this study is to evaluate the effects of a repositioning procedure of such ankylosed permanent front teeth by a distraction osteogenesis procedure. Five patients (mean age 13.4 years), with an ankylosed permanent front tooth in the anterior area, were enrolled in the present study. After the pre-operatory orthodontic preparation, each selected site was treated with single-tooth dento-alveolar block osteotomy surgery performed with a piezoelectric surgery device with ultrasonic cuts on the buccal side. Subsequently, a custom distraction device, made by a resin splint and a sector expansion screw, was set in such a way it delivered a force with direction and sense towards the planned position of the tooth as well as the osteotomy's incision. After a latency period of 14 days, the distraction of the dento-alveolar block was started with a rate of distraction of 0.8 mm per day. The average shift obtained by the ankylosed teeth was 7.8 ± 0.75 mm (±SD), and the ankylosed tooth was regularly positioned into the occlusion in 20.4 ± 1.85 days (±SD), with a slight relapse (±0.5 mm) observed after 1 year. This study indicates that a therapeutic approach combining piezoelectric surgery and orthodontic therapy may be useful for the treatment of ankylosed permanent teeth in the frontal area with a long-term follow-up over 5 years.

Optimization of electronic prescription for parallel external fixator based on genetic algorithm.

For the parallel external fixator, there are some defects, such as uneven distraction rate, unbearable pain and uncontrollable movement trajectory in practical clinical applications. In order to solve the problems, a new deformity correction algorithm, which is used to calculate the elongation of the six struts, is developed. Meanwhile, the corresponding computer software for getting the electronic prescription is developed. First, the trajectory of the moving bone is planned by Cartesian coordinate path control. Next, the prescription is obtained from the trajectory by the inverse pose solution algorithm. Finally, the genetic algorithm is utilized to optimize the achieved prescription. From the year of 2015 to 2018, twenty-three patients with complicated tibia deformity are treated by using parallel external fixator and the developed computer software. All patients have standing, patella-forward, full-length post-operative AP and lateral radiographs of the lower limbs with the complete proximal ring for getting the deformity parameters and frame parameters. These parameters are input into the computer software to calculate a daily prescription schedule for strut adjustment. Radiographs are taken regularly to determine the effects of recovery during the correction process. The mean time of follow-up is 18months (range 11-40months). All patients reach the requirements for deformity correction, and their symptoms and appearance are improved significantly. No cases of wound infections or complications occur, and no severe pain came as well during the correction process. By using the computer-aided parallel external fixator for the correction of lower limb deformities, satisfactory outcomes can be achieved. Hence, this method greatly improved the treatment of these patients in a clinical application.

Perceived vs. actual distractions in the emergency department

IntroductionThe emergency department (ED) has been shown to be an interrupt-driven workplace fraught with potential for distractions and interruptions that increase the potential for medical error. Accuracy of provider perception of these distractions and interruptions has yet to be investigated. MethodsAn observational two-phase study was conducted over a 9-week period in the highest acuity zone of the ED at an urban, academic medical center with about 90,000 visits/year. Phase I, conducted over the initial 5-weeek period, consisted of observers recording the type and frequency of all overhead pages in the ED. In phase II, conducted over the final 4-week period, direct observation of faculty and residents was done to record all individual interruptions for different levels of training. Actual data was compared to provider perceptions, as determined by survey responses. Results2438 overhead pages were recorded and occurred, on average, 23.2 times per shift. The perceived rate of overhead pages was 43.2 per shift. 333 individual interruptions occurred, on average, 4.26 times per shift. The perceived rate was 53.5 per shift. Attending providers perceived a significantly higher number of individual interruptions compared to all resident providers. ConclusionThe perceived amount and rate of distractions and interruptions are significantly higher than the actual amount and rate of distractions and interruptions. Attending physicians both perceive and experience more distractions and interruptions. Further work should be done to evaluate the power of provider perception, and the potential contribution of inaccurate perception to medical error and provider burnout.

Exosomes secreted by endothelial progenitor cells accelerate bone regeneration during distraction osteogenesis by stimulating angiogenesis

BackgroundDistraction osteogenesis (DO) is an effective but lengthy procedure to fully induce bone regeneration in large bone defects. Accumulating evidence supports the role of exosomes secreted by endothelial progenitor cells (EPC-Exos) in stimulating angiogenesis, which is closely coupled with osteogenesis. This study aimed to investigate whether EPC-Exos promote bone regeneration during DO in rats.MethodsExosomes were isolated from the supernatants of rat bone marrow EPCs via ultracentrifugation and characterized via transmission electron microscopy, tunable resistive pulse sensing analysis, and western blot analysis. Unilateral tibial DO models were generated using 68 Sprague-Dawley rats with a distraction rate of 0.5 mm per day for 10 days. After local injection of EPC-Exos into the distraction gaps after distraction, the therapeutic effects of EPC-Exos on bone regeneration and angiogenesis were assessed via X-ray, micro-computed tomography (micro-CT), and biomechanical and histological analyses. Pro-angiogenic effects and the potential mechanism underlying the effects of EPC-Exos on human umbilical vein endothelial cells were subsequently evaluated via in vitro assays including Cell Counting Kit-8, wound healing, tube formation, and western blot assays.ResultsEPC-Exos were spherical or cup-shaped vesicles ranging from 50 to 150 nm in diameter and expressed markers including CD9, Alix, and TSG101. X-ray, micro-CT, and histological analyses revealed that bone regeneration was markedly accelerated in rats treated with EPC-Exos. The distracted tibias from the Exos group also displayed enhanced mechanical properties. Moreover, vessel density was higher in the Exos group than in the control group. In addition, in vitro analyses revealed that EPC-Exos enhanced the proliferation, migration, and angiogenic capacity of endothelial cells in an miR-126-dependent manner. Further, EPC-Exos downregulated SPRED1 and activated Raf/ERK signaling.ConclusionsThe present results show that EPC-Exos accelerate bone regeneration during DO by stimulating angiogenesis, suggesting their use as a novel method to shorten the treatment duration of DO.

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Introduction Reduction of the period of limb lengthening with the Ilizarov method and preservation of limb functions in large elongations are the tasks to be solved by modern traumatology and orthopedics. The aim was to study the functional state of the limb, dynamics of the tibial regenerate formation, histostructural changes in the articular cartilage and the tibial nerve under the conditions of automatic high-frequency elongation of the tibia with the method of transosseous distraction osteosynthesis at a rate of 3 mm using a preliminary Z-shaped achillotomy. Material and methods The 24-hour high-fractional mode provided with automatic distractor was used to lengthen tibiae of 12 adult mongrel dogs with the method of transosseous distraction osteosynthesis. Distraction rate was 3.0 mm per day in 120 steps. To prevent formation of foot equinus, a Z-shaped achillotomy was performed. Methods of light microscopy, morphometry and X-ray electron probe microanalysis were used to study the distraction regeneration in the tibia, the articular cartilage of the medial condyle of the femur and the tibial nerve. Results During the periods of distraction and fixation, the regenerate was characterized by a normotrophic structure with a large proportion of bone component which provided the limb support function after 45 days of the experiment. Thirty days after the removal of the apparatus, a newly formed bone of a typical structure was seen in the distraction gap. Achillotomy helped prevent equinus deformity of the foot and flexion contractures of the knee joint and the metatarsal joint. However, histostructural changes in the articular cartilage were detected at the stages of osteosynthesis. Despite the restoration of the thickness of the cartilage, there was a decrease in the number of isogenic groups and the presence of cells with chondoptosis by the end of the experiment. Not a single case of neuropathy of the tibial nerve was revealed histologically due to prevention of overstretching of the anterior surface of the tibia by an increase in the length of the calcaneal tendon with tenotomy. The proportion of destructively altered nerve fibers in all animals did not exceed 5 %. Necrobiotic changes in the epineural vessels were compensated by hypervascularization of the epineurium and endonevria, as a result of which the majority of nerve conductors retained their normal structure, numeric density, and restored dimensional characteristics at the end of the experiment. Conclusions The conditions of the experiment provide for functional restoration of the limb, promote active reparative osteogenesis and structural adaptation of the tibial nerve, do not cause any gross destructive changes in the articular cartilage and reduce the period with the Ilizarov frame on by 30 % as compared with the classical variant.

In the lab and in the wild: How distraction and mind wandering affect attention and memory

The present study examined the impact that the environment has on the ability to remain attentive and retain information. Participants listened to an audiobook in either a controlled lab setting or in an uncontrolled natural setting. While listening to the audiobook, participants were randomly prompted to report their current attentional status (focused, mind wandering, or distracted). Participants performed a memory test on audiobook content at the end. Inattention (mind wandering and distraction) did not differ between the two settings. However, there was a setting by attentional state interaction: distraction rates were higher than mind wandering rates outside the lab, while inattention rates did not differ inside the lab. Memory test performance was poorer outside the lab, suggesting that increased distraction may compromise memory more than mind wandering. Collectively, the data suggest that mind wandering and distraction are distinct types of attentional failures and that past controlled lab investigations may have overestimated the role of mind wandering and underestimated the role of distraction in everyday cognition.

Using time pressure and note-taking to prevent digital distraction behavior and enhance online search performance: Perspectives from the load theory of attention and cognitive control

Digital distraction has become a chronic behavior problem for university students that interferes with their attention and learning within personalized learning environment. Applying a randomized control block trial with a counterbalanced experimental design, we investigated the effect of note-taking strategies and time pressure on students' task-irrelevant browsing behaviors and online search performance. Students were randomly assigned to a matrix note, conventional note, or note-free condition and then to one of the four experimental blocks, counterbalancing the order of online search topics and time pressure. Results of the study showed that 44 out of 60 participants (73.33%) conducted at least an irrelevant browsing. Students in the matrix note condition and those under high time pressure exhibited a lower task distraction rate. Moreover, students taking matrix notes demonstrated better online-search performance. Note-taking strategies and task distraction rate were significant predictors of participants' online search performance controlling for their prior knowledge. Study results are consistent with the load theory of attention and cognitive control and have implications to reduce student distraction and improve learning effectiveness.

Validating a real-time perceptual model predicting distraction caused by audio-on-audio interference

This work concentrates on validating a real-time perceptual model predicting distraction caused by audio-on-audio interference. The real-time model was recently developed on the basis of another successfully validated, perceptual distraction model, which is not able to calculate predictions in real time. Both models are non-blind, i.e., their inputs take target and interferer signals separately. This paper describes a validation experiment for the real-time distraction model, which compares the model's predictions to subjective distraction ratings obtained from a listening experiment. The accuracy of the real-time model is also compared to that of the original distraction model. The calculated root-mean-squared errors for a speech zone and a music zone were 10.2% and 12.6% for the real-time model, respectively, compared to 11.3% and 11.5% for the original model. The results indicate that the real-time model is able to predict the distraction with similar accuracy as the original model, and thus, is a suitable tool for sound-zone evaluation. Furthermore, the real-time capability of the model is considered to be vital for certain applications, including the evaluation of adaptive sound zones.

Abstract 17.50 CRANIOFACIAL DISTRACTION IN MANAGEMENT OF ANTERIOR PLAGIOCEPHALY: A NOVEL IDEA AND A SYSTEMATIC REVIEW OF THE LITERATURE

BACKGROUND: The objective of this article is to present a review of all reports included management of uni-coronal synostosis with distraction osteogenesis. Also, we innovated a new method in the treatment of cases of anteriorPlagiocephaly in an early time using distraction osteogenesis. METHODS: We present a case in which the anterior plagiocephaly was treated by distraction osteogenesis of both metopic and hemicoronal sutures in a four-month-old female patient. A comprehensive systematic review was completed using key search terms, including distraction, uni-coronal synostosis, anterior plagiocephaly, craniosynostosis. We excluded all experimental articles and picked up the clinical reports which show the usage of Distraction Osteogenesis in the management of uni-coronal synostosis. The study sample of this review consisted of 16 reports that, we analyzed them in detail. RESULTS: Over 17 years, 16 articles were published in seven journals reported the use of DO in the treatment of Unicoronal Synostosis. A total number of patients treated by DO were 120, the mean age at operations was 12 months. In the case presented, The rate of distraction was 1/3 mm/day for the metopic suture for 48 days and 2/3 mm/day for the right coronal suture for 30 days. Successful distraction osteogeneses for both sutures were achieved with adequate correction of cranioorbital dysmorphology. CONCLUSION: Distraction Osteogenesis is one of the mainstay treatments in uni-coronal synostosis. We believe that distraction of both metopic and hemicoronal in anterior plagiocephaly could improve the shape and restore the midline shift. KEYWORDS: distraction; uni-coronal synostosis; anterior plagiocephaly; craniosynostosis.

Causes of peroneal neuropathy associated with orthopaedic leg lengthening in different canine models

Peroneal neuropathy is one of the complications of orthopaedic leg lengthening. Methods of treatment include slowing of distraction and decompression both of which may lead to additional complications. The purpose of this study was to analyse the changes in histologic peroneal nerve structure during experimental orthopaedic lengthening using various modes of manual or automatic distraction. The obtained data provide the basis for better understanding of peroneal neuropathy pathogenesis and refinement of prophylaxis and preventive treatment protocols. Four experimental models of canine leg lengthening using the Ilizarov fixator were studied: 1 (n = 10)—manual distraction—1 mm/day divided into four increments; 2 (n = 12)—automatic distraction—1 mm/day in 60 increments, 3 (n = 9) and 4 (n = 9)—increased rate of high frequency automatic distraction: 3 mm/day in 120 and 180 increments, respectively. In peroneal nerves semi-thin sections cross-sectional fascicular areas, content of adipocytes in epineurium, endoneurial vascularisation, morphometric parameters of nerve fibres were assessed by computerised analysis at the end of distraction and of consolidation periods and 30 days after fixator removal. In Groups 1–2 massive nerve fibre degeneration along with epineural vessels obliteration was revealed in two cases from 22, whereas in Groups 3–4 there were 10 from 18 (p < 0.01). Injuries of perineurium and endoneurial vessels were noted in Group 3, and long-lasting thinning of nerve fascicles in Group 4. The decrease in epineurial fat tissue was revealed in all groups, more drastic in 3. Modifications and injuries of nerve sheaths and blood vessels depending on distraction rate and frequency contribute to peroneal neuropathy. Its mechanical, circulatory and metabolic causes are discussed.

Accordion technique used in treatment of hypertrophic nonunion

Objective To evaluate the therapeutic effects of the accordion technique used in external fixation for long bone hypertrophic nonunion. Methods From August 2013 to December 2015, 13 patients with hypertrophic nonunion were treated by the accordion technique (distraction, compression and re-distraction) used together with an Ilizarov ring external fixator or a monolateral external fixator. They were 10 males and 3 females with an average age of 44.6 years (from 18 to 63 years). The nonunion occurred in the middle femur in 5 patients, in the femoral supracondyle in one, in the tibial diaphysis in 4, and in the distal tibia in 3. The procedure was performed with a preassembled external fixator without open surgery or bone graft. The pathological sites were gradually distracted (0.25 mm/day) from the seventh day postoperatively. In case of deformity, correction was conducted to restore the alignment. At the same rate of distraction, compression was started after the equal length was achieved and next followed by distraction. The frequency of cycle depended upon the callus observed in the X-rays. Results The mean follow-up for the 13 patients was 19 months (from 10 to 38 months) after removal of the external fixator. All the cases of hypertrophic nonunion obtained bony union after a mean duration of 7.5 months (from 5 to 13 months). No nonunion or deformity recurred during the follow-up. The complications such as pin-site infection (in 4 cases) and mild Achilles's tendon contracture (in 2 cases) were prevented or treated by careful nursing and rehabilitation. Conclusion The accordion technique together with an external fixator is a reliable and effective treatment for hypertrophic nonunion. Key words: External fixators; Bone regeneration; Fractures, ununited; Accordion technique

Simulating lateral distraction osteogenesis.

Distraction osteogenesis is an effective method for generating large amounts of bone in situ for treating pathologies such as large bone defects or skeletal malformations, for instance leg-length discrepancies. While an optimized distraction procedure might have the potential to reduce the rate of complications significantly, our knowledge of the underlying mechanobiological processes is still insufficient for systematic optimization of treatment parameters such as distraction rate or fixation stiffness. We present a novel numerical model of lateral distraction osteogenesis, based on a mechanically well-controlled in vivo experiment. This model extends an existing numerical model of callus healing with viscoplastic material properties for describing stress relaxation and stimuli history-dependent tissue differentiation, incorporating delay and memory effects. A reformulation of appositional growth based non-local biological stimuli in terms of spatial convolution as well as remeshing and solution-mapping procedures allow the model to cope with severe mesh distortions associated with large plastic deformations. With these enhancements, our model is capable of replicating the in vivo observations for lateral distraction osteogenesis in sheep using the same differentiation rules and the same set of parameters that successfully describes callus healing in sheep, indicating that tissue differentiation hypotheses originally developed for fracture healing scenarios might indeed be applicable to distraction as well. The response of the model to modified distraction parameters corresponds to existing studies, although the currently available data is insufficient for rigorous validation. As such, this study provides a first step towards developing models that can serve as tools for identifying both interesting research questions and, eventually, even optimizing clinical procedures once better data for calibration and validation becomes available.

A Comparison of Femoral Lengthening Methods Favors the Magnetic Internal Lengthening Nail When Compared with Lengthening Over a Nail.

Bone lengthening with an internal lengthening nail (ILN) avoids the need for external fixation and requires one less surgical procedure than lengthening over a nail (LON). However, LON has been shown to be superior to femoral internal lengthening using a mechanical nail. The magnetic ILN, a remote-controlled and magnet-driven device, may have overcome the weaknesses of earlier internal lengthening technology and may be superior to LON. (1) Is the magnetic ILN more accurate than LON for femoral lengthening? (2) Does the magnetic ILN demonstrate more precise distraction rate control than LON? (3) Does the magnetic ILN result in faster regenerate site healing, with more robust callus, than LON? (4) Does the magnetic ILN result in fewer complications, including impediments to knee motion, than LON? We conducted a retrospective comparison of the records and radiographs of 21 consecutive patients with 22 femoral lengthenings using LONs and 35 consecutive patients with 40 femoral lengthenings using remote-controlled magnetic ILNs. Primary outcomes measured included accuracy, distraction rate precision, time to bony union, final knee range of motion, regenerate quality, and complications. The minimum follow-up times for the LON and ILN cohorts were 13 and 21months, respectively. Patients treated with ILN had a lower post-treatment residual limb-length discrepancy (0.3mm) than those treated with LON (3.6mm). The rate of distraction was closer to the goal of 1mm/day and more tightly controlled for the ILN cohort (1mm/day) than that for the LON group (0.8mm/day; SD, 0.2). Regenerate quality was not significantly different between the cohorts. Bone healing index for ILN was not statistically significant. Time to union was shorter in the ILN group (3.3months) than that in the LON group (4.5months). A lower percentage of patients experienced a complication in the ILN group (18%) than in the LON group (45%). Knee flexion at the end of distraction was greater for ILN patients (105°) than that for LON patients (88.8°), but this difference was no longer observed after 1year. Femoral lengthening with magnetic ILN was more accurate than with LON. The magnetic ILN comports the additional advantage of greater precision with distraction rate control and fewer complications. Both techniques afford reliable healing and do not significantly affect knee motion at the final follow-up. The magnetic ILN method showed no superiority in regenerate quality and healing rate.

Relationship of distraction rate with inferior alveolar nerve degeneration-regeneration shift.

Distraction osteogenesis is an important technique for the treatment of maxillofacial abnormities and defects. However, distraction osteogenesis may cause the injury of the inferior alveolar nerve. The relationship between distraction rate and nerve degeneration-regeneration shift remains poorly understood. In this study, 24 rabbits were randomly divided into four groups. To establish the rabbit mandibular distraction osteogenesis model, the mandibles of rabbits in distraction osteogenesis groups were subjected to continuous osteogenesis distraction at a rate of 1.0, 1.5 and 2.0 mm/d, respectively, by controlling rounds of screwing each day in the distractors. In the sham group, mandible osteotomy was performed without distraction. Pin-prick test with a 10 g blunt pin on the labium, histological and histomorphometric analyses with methylene blue staining, Bodian's silver staining, transmission electron microscopy and myelinated fiber density of inferior alveolar nerve cross-sections were performed to assess inferior alveolar nerve conditions. At 28 days after model establishment, in the pin-prick test, the inferior alveolar nerve showed no response in the labium to a pin pricks in the 2 mm/d group, indicating a severe dysfunction. Histological and histomorphometric analyses indicated that the inferior alveolar nerve suffered more degeneration and injuries at a high distraction rate (2 mm/d). Importantly, the nerve regeneration, indicated by newborn Schwann cells and axons, was more abundant in 1.0 and 1.5 mm/d groups than in 2.0 mm/d group. We concluded that the distraction rate was strongly associated with the inferior alveolar nerve function, and the distraction rates of 1.0 and 1.5 mm/d had regenerative effects on the inferior alveolar nerve. This study provides an experimental basis for the relationship between distraction rate and nerve degeneration-regeneration shift during distraction osteogenesis, and may facilitate reducing nerve complications during distraction osteogenesis.

Метаболизм тканей кисти и функциональные резервы микроциркуляции у пациентов с последствиями экстремального воздействия холодового фактора при лечении по Илизарову

Objective To explore metabolism and microcirculation of the hand in patients with remote effects of severe cold injury treated with the Ilizarov method using functional tests. Material and methods Metabolism and microcirculation of the hand were studied in 19 patients with remote effects of severe cold injury treated with the Ilizarov method. The patients’ age ranged from 24 to 46 years (32.8 ± 2.9 years). Control group consisted of 14 normal peers. Depending on finger stump length, presence of contractures in adjacent joints and postlengthening basal syndactyly techniques employed for treatment included finger stump lengthening (4 observations of less than 30 mm stumps and 10 observations of more than 30 mm stumps); finger stump lengthening followed by plasty of web space in 3 patients; finger stump lengthening and repair of adduction contracture in 2 cases. Laser Doppler Flowmetry (LDF) BLF21 (Transonic Systems Inc., U.S.A.) was used to assess microcirculatory function. Local vascular occlusion test was applied, blood flow recorded at rest and after 3 minute ischemia, and Peak Capillary Blood Flow Index calculated (PBFI, % = CBFpeak/CBFrest × 100 %), Δ t, sec – period from occlusion relief to maximal runup of capillary blood flow. A Doppler ultrasound (DUS) using diagnostic Minimaxdoppler K device (St.Petersburg) was used to assess peripheral hemodynamics of finger and stump arteries. Results DUS showed signs of vasoconstriction of digital arteries. Period of CBF semi-recovery and length of reactive hyperemia were sharply decreased. Transcutaneous polarography showed prevailing anaerobic metabolism with two-fold decrease in рО2 half-life and two-fold increase in рО2 semi-recovery, and oxygen exhaust was recorded within 2 minutes. Conclusion It was concluded that evaluation of capillary blood flow using laser Doppler flowmetry with a 3-minute vascular occlusion test was the method of choice for examination of patients with sequelae of severe cold injury of limb segments. The method allowed for assessing preclinical extent of ischemia, disorders in vascular reactivity of pre-capillary portion. A tailored approach to distraction rate under control of objective and subjective findings and microhemodynamics is essential for patients treated with transosseous distraction osteosynthesis using Ilizarov external fixator. Medications targeting the relief of vasoconstriction prescribed for patients with sequelae of cold injury treated with Ilizarov traction demonstrated hardly noticeable effect due microcirculation recourses had been largely consumed by the method of transosseous osteosynthesis. We suggest that preventive angiogenic and neurotrophic therapies can be efficient at pre-distraction stage.

Metacognition in Auditory Distraction: How Expectations about Distractibility Influence the Irrelevant Sound Effect.

Task-irrelevant, to-be-ignored sound disrupts serial short-term memory for visually presented items compared to a quiet control condition. We tested whether disruption by changing state irrelevant sound is modulated by expectations about the degree to which distractors would disrupt serial recall performance. The participants’ expectations were manipulated by providing the (bogus) information that the irrelevant sound would be either easy or difficult to ignore. In Experiment 1, piano melodies were used as auditory distractors. Participants who expected the degree of disruption to be low made more errors in serial recall than participants who expected the degree of disruption to be high, independent of whether distractors were present or not. Although expectation had no effect on the magnitude of disruption, participants in the easy-to-ignore group reported after the experiment that they were less disrupted by the irrelevant sound than participants in the difficult-to-ignore group. In Experiment 2, spoken texts were used as auditory distractors. Expectations about the degree of disruption did not affect serial recall performance. Moreover, the subjective and objective distraction by irrelevant speech was similar in the easy-to-ignore group and in the difficult-to-ignore group. Thus, while metacognitive beliefs about whether the auditory distractors would be easy or difficult to ignore can have an effect on task engagement and subjective distractibility ratings, they do not seem to have an effect on the actual degree to which the auditory distractors disrupt serial recall performance.

Effects of Local Low-Dose Alendronate Injections Into the Distraction Gap on New Bone Formation and Distraction Rate on Distraction Osteogenesis.

Bisphosphonates that constrain bone resorption have a direct effect on osteoclast function. In this experimental study, the effects of low-dose local alendronate injections on the distraction gap (DG) in rabbit mandible at 2 different rates were evaluated.The experimental study was conducted on 20 male, New Zealand white rabbits. The animals were divided into 3 experimental groups and 1 control group. Group 1 consisted of animals with distraction at the rate of 1 mm/day, receiving postoperative local low-dose alendronate local injections into the DG. Group 2 consisted of animals with distraction at the rate of 2 mm/day, receiving postoperative 0.75 μg/kg of alendronate local injections into the DG. Group 3 consisted of animals with distraction at the rate of 2 mm/day, receiving postoperative 0.2 mL local saline injections into the DG. Group 4 consisted of animals with distraction at the rate of 1 mm/day, receiving postoperative 0.2 mL local saline injections into the DG. All the injections were performed immediately postoperatively and for all groups at 1, 2, 3, and 4 weeks following surgery. The distraction zones were evaluated using dual-energy X-ray absorptiometry and histological analysis.Histologically, bone healing was found to be significantly accelerated in Groups 1 and 4 compared with Groups 2 and 3 (P < 0.05). Bone healing was superior in Group 1 and the difference was statistically significant compared with Group 4. There was a significant increase in mean bone mineral density in the 1 mm daily rate groups (Groups 1 and 4) compared with the 2 mm daily rate groups (Groups 2 and 3) (P < 0.05).Local low-dose alendronate injections could be an effective way for improving bone formation in distraction osteogenesis. Furthermore, the results of this study did not support the hypothesis that injections of local low-dose alendronate may allow 2 mm/day instead of 1 mm/day of elongation in the rabbit mandible.