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PubMed1998

Skeletal expansion combined with soft-tissue reduction in the treatment of obstructive sleep apnea in children: physiologic results.

Twenty consecutive children, ranging in age from 6 days to 18 years, were treated with skeletal expansion, in addition to soft-tissue reduction, for medically refractory obstructive sleep apnea. The underlying diagnoses were craniofacial microsomia (n = 6), Down syndrome (n = 3), Pierre Robin syndrome (n = 3), cerebral palsy (n = 3), Nager's syndrome (n = 1), Treacher Collins syndrome (n = 1), cri du chat syndrome (n = 1), juvenile rheumatoid arthritis (n = 1), and temporomandibular joint ankylosis (n = 1). Fourteen children had severe medically refractory sleep apnea and were tracheostomy candidates; in the remaining six, tracheostomies were placed shortly after birth and could not be decannulated. Overnight, 12-channel polysomnography was obtained before and after surgery. The mean apnea index improved from 7.42 to 1.26, the mean respiratory disturbance index improved from 25.24 to 1.72, and the mean lowest apnea-related oxygen saturation improved from 68% to 88%. Of the 14 children with medically refractory obstructive sleep apnea, two required tracheostomies. Of the six patients with tracheostomies, five have been decannulated at the time of this writing. Skeletal expansion in conjunction with soft-tissue reduction in the pediatric population permits substantial increases in the volume of both the nasopharynx and oropharynx. Creative use of conventional osteotomies and the application of distraction osteogenesis have enabled surgeons to apply maxillofacial and craniofacial techniques in treating children with obstructive sleep apnea.

Adolescent↗
PubMed1995

Surgically assisted rapid orthodontic lengthening of the maxilla in primates--a pilot study.

Orthodontic and surgical treatment of patients with maxillary retrusion and/or midface hypoplasia is challenging. This study was designed to show that the maxilla can be successfully lengthened by surgical assisted rapid orthopedic movement, using the principles of distraction osteogenesis. Three experimental and three control adolescent cynomolgus primates were used in this study. Metallic markers were placed in the cranial base and the maxilla and cephalometric x-ray films were taken. An orthodontic appliance was constructed with a Glen-Ross screw (Dentaurum, Newtown, Pa.) oriented anteroposteriorly. Anterior supraapical osteotomies of the maxilla were carried out. Bilateral horizontal and interdental osteotomies were created between the first premolars and the canine; the anterior six tooth dental-osseo segment was completely mobilized in all animals. Beginning 1 week after surgery, the orthodontic appliance was opened a quarter turn every 2 days until the anterior segment was advanced by 4 mm in two animals and 6 mm in one animal. Animals were killed at 6, 8, and 12 weeks after completion of the maxillary orthopedic advancement. Computerized tomographic scans of the maxillae were completed, and the specimens were then prepared by routine histologic methods for examination by light microscopy. The computerized tomographic scans showed bone deposition in the osteotomy sites, which was confirmed by histologic observations. Since this technique demonstrated repair by bone rather than soft connective tissue in the osteotomy sites, this procedure could be a useful method of treating midface retrusion.

Animals↗
PubMed2000

Molecular events caused by mechanical stress in bone.

The shape of bone changes as a result of bone remodeling corresponding to physical circumstances such as mechanical stress. The tissue which receives the loaded mechanical stress most efficiently is bone matrix. Recent studies revealed the function of osteocytes as mechanosensors in the early stage of bone remodeling. Loaded mechanical stress is converted to a series of biochemical reactions, and finally activates osteoclasts and osteoblasts to cause bone resorption and formation. Biochemical and molecular biological studies have recently resulted in the identification of the gene of which expression level is changed by mechanical stress. Nitric oxide (NO) and cAMP is secreted in response to mechanical stress in the immediate early stage. Genes encoding enzymes such as glutamate/aspartate transporter (GLAST), nitric oxide synthetase (NOS) and prostaglandin G/H synthetase (PGHS-2) are identified as mechanical stress-responsive. The expression level of IGF-I is enhanced under the control of PTH/PTHrP. The expression of c-fos is increased by loading of mechanical stress. AP1, a heterodimer of c-FOS/c-JUN, functions as a transcription factor of downstream gene(s). Elements including AP1 sites, cyclic AMP response elements (CRE) and shear stress response elements (SSRE) are found in the promoter region of mechanical stress-response genes. The enhanced expression of osteopontin (OPN) in the osteocytes of bone resorption sites was demonstrated by in situ hybridization and immunohistochemistry and transdifferentiation of chondrocytes with the abundant expression of BMP-2 and -4 in the process of distraction osteogenesis was observed.

Animals↗
PubMed1999

Lengthening of pediatric forearm deformities using the Ilizarov technique: functional and cosmetic results.

Eight patients (average age, 10 years) had a unilateral forearm lengthening procedure using the technique developed by Ilizarov. The procedure was performed in 4 patients with radial agenesis, in 2 with multiple hereditary exostosis, in 1 with ulnar agenesis, and in 1 with multiple enchondromatosis. Patients underwent distraction osteogenesis through either a unifocal or bifocal corticotomy. Forearm length increased on average 6.0 cm (range, 3.6-8.1 cm) or 54% (range, 21% to 94%) with a lengthening index of 1.3 months per centimeter (range, 0.6-1.9 months per centimeter). The length of follow-up averaged 4.5 years and involved office examinations with task evaluation and a questionnaire addressing function and appearance. Limb length discrepancy at follow-up measured 3.7 cm (range, 0.0-8.0 cm). Lengthening of the forearm was found to improve upper extremity function; it allowed the patient to reach distant body parts and to perform select activities requiring near-equal arm length. Forearm lengthening also improved the appearance of the arm if adequate soft tissue was preserved. Full restoration of arm length was not a requirement for a successful outcome and patient satisfaction with the results of the procedure was high.

Adolescent↗
PubMed2002

Surgical strategies in the treatment of complex obstructive sleep apnoea in children.

Complex OSA in children is a challenging problem that requires careful team management. Evaluation includes history, physical examination and appropriate radiological and endoscopic studies. Twelve-channel polysomnography, with or without a pH probe, is mandatory in children with OSA to determine the severity and to document the efficacy of treatment. A variety of individual problems and nuances arise and will continue to do so. Clinical experience and a high degree of suspicion in the craniofacial population is necessary to rule out the existence of OSA in a given patient. Newer treatment modalities, such as distraction osteogenesis of the mandible and midface, have revolutionised treatment of OSA during childhood. Although still the gold standard of care, tracheostomy is not a benign procedure and the toll on both the patient and family can be devastating.

Cerebral Palsy↗
PubMedDate not supplied

[Correction of deformities with conventional and hexapod frames--comparison of methods].

AIM: Distraction osteogenesis for the correction of deformities with an external fixator is well established. The hexapod principle of robotic technique was invented for the Ilisarov apparatus (e. g. Taylor-Spatial-Frame/TSF). Treatment with conventional frames needs a patient-customised frame mounting. This demanding procedure is markedly reduced using this technology. The aim of this study was to analyse the value of the hexapod principle in external fixation. METHOD: The potential of a frame to correct deformities is limited by its work space. The geometry of a conventional frame is different from the geometry of a hexapod frame, which is the reason for their different work spaces. The work space of the hexapod frame is compared to the work space of a conventional frame. Important parameters for this analyses are minimal and maximal frame heights and the potential of correction. RESULTS: The minimal frame height of hexapod fixators is higher compared to conventional Ilisarov fixators. The standard hexapod frame (TSF 155 mm ring diameter) can correct 23 degrees of angulation, 36 mm of shortening, 71 mm of translation and 43 degrees of rotation without changing the telescope rods. The standard conventional frame (160 mm ring diameter) can correct 90 degrees of angulation, 100 mm of shortening, 25 mm of translation and 12.5 degrees of rotation without remounting of the frame. CONCLUSION: The different work spaces of the different frames result in consequences for their clinical application. The hexapod frame has more power to correct translation and rotational deformities than a conventional frame. Correction of extensive angulation and shortening deformities almost always needs an exchange of telescopic rods. Conventional frames are usually able to correct these deformities with the primary mounting. Because of its increased minimal frame height, the indication for hexapod constructs in child orthopaedics can be limited.

Adolescent↗
PubMed2003

Lateral Transmandibular Approach to the Skull Base in Children: Three Case Reports.

The choice of surgical approach to tumors of the cranial base in children is determined by strict criteria. The criteria include optimal visibility for the surgeon, minimal possible impairment of facial skull growth, and the preservation of motor and sensory nerve integrity. From 1993 to 1996, three children (6 years old, 22 months old, 6 months old, respectively) underwent surgery to resect cranial base tumors through a modified lateral transmandibular approach. In all three patients a preauricular incision with temporal and submandibular extensions was performed. After the mandible was prepared, an osteotomy was conducted cranially to the mandibular foramen. When the capitulum was temporarily disarticulated, wide access to the cranial base was provided and the tumors were resected. Two of these children were available for follow-up, and we continue to observe their development. Given the severity of their conditions, treatment yielded good results. Growth impairment of the mandible was corrected by the distraction osteogenesis technique.

Case Reports↗
PubMed2000

Changes in blood flow during one stage lengthening of bone: an experimental study in rats.

Distraction osteogenesis is a well-accepted method of bone lengthening. Its disadvantages, however, are that it requires an external fixator and takes a long time. One-stage lengthening therefore offers certain advantages. A first point of reference for the safe limits of this procedure might be the changes of blood flow, and this is also the crucial factor in deciding on the appropriate method of lengthening, particularly where the hand or foot is involved. Using a laser Doppler flowmeter we measured blood flow in the dorsum of the foot after using bilateral minimonofixators to lengthen the tibias of 15 Sprague-Dawley rats. They were lengthened in four stages: stage 0 (before lengthening); stage I--12.5%; stage II--25%; and stage III--31.25% of lengthening. The blood flow during stage I decreased to 79% compared to that of stage 0; 16% during stage II; and 1% during stage III. This study suggests that the maximal permissible extent of lengthening might be less than a quarter according to the blood flow as suggested by this animal model.

Animals↗
PubMed2000

Expression of adenovirally delivered gene products in healing osseous tissues.

Gene therapy has moved from the promise of laboratory investigation to the reality of clinical practice in just the last decade. Various methods for delivery of genes to host cells have been developed and utilized both in vitro and in vivo. From the perspective of the plastic surgeon, gene therapy holds the promise to augment healing in clinical situations that remain difficult to treat, such as chronic wounds, osteoradionecrosis, or possibly to expedite current clinical practices, such as distraction osteogenesis. The authors chose to investigate the potential for gene therapy in osseous tissues using a replication-deficient adenovirus vector to deliver the marker transgene beta-galactosidase. An adenovirus vector is ideal for use in situations in which transgene expression is desired for only a relatively short period of time, such as wound and fracture healing. Utilizing a rat mandibular osteotomy model, they demonstrated that, using an adenoviral vector, foreign genes can be delivered in a simple fashion and can be expressed in a reliable manner within and around the osteotomy site for at least 10 days. Furthermore, there was no evidence of transfection of distant tissues associated with local application of the adenovirus vector. With this information, clinicians may now attempt to deliver osteogenic and angiogenic genes in a site-specific fashion to improve and expedite osseous healing.

Adenoviridae↗
PubMed1993

Distraction of the frontal bone outside the cranial plane: a rabbit model.

Distraction of the frontal bone outside the cranial plane using the Ilizarov principle was performed in 17 22-week-old New Zealand white rabbits. Five rabbits had frontal bone osteotomy only and were in the control group; 5 rabbits were placed in the sham control group and had frontal bone osteotomy plus application of a customized headgear appliance; and 7 rabbits were placed in the experimental group, which underwent frontal bone osteotomy application of the headgear and distraction. The frontal bone was elevated 1 mm every other day for a period of 8 weeks, and the animals were then killed. Cephalometry was performed both preoperatively and at the end of the 8-week period. Histological examination of the skulls was also performed. The experimental group showed a significantly elevated frontal bone compared to the sham control group (p < 0.05). Callous bone filled the distracted segment, which united the frontal bone with the cranial plane. Therefore, frontal bone advancement by distraction osteogenesis is possible using this rabbit model.

Animals↗
PubMed2002

Morphological variability of inferior alveolar nerve in low-grade craniofacial microsomia.

Craniofacial microsomia (CFM) involves asymmetric hypoplasia and dysmorphogenesis of the facial skeleton. Certain aspects of CFM may be treated by surgical osteotomy and distraction osteogenesis (DO). Mandibular osteotomy places the inferior alveolar nerve at risk. The aim of this study was to investigate radiological landmark relationships to the anatomy of the inferior alveolar nerve in CFM. Application of this understanding will aid intraoperative protection of the inferior alveolar nerve. Six subjects with similar presentations of hemifacial microsomia were selected. Three-dimensional reconstruction CT images was used to locate bony structures that held important relationships with the inferior alveolar nerve. Measurements (of the normal and microsomic sides) were made between fixed landmarks: mandibular notch, mandibular foramen, condyle, back of second and third molar tooth, and mental foramen. The unaffected sides acted as controls. The distance between the normal and the microsomic sides from condyle to mandibular foramen was significantly different. The sizes of condyles differed significantly between the normal and microsomic sides. Most of the remainder of the vertical distance of the ramus and most of the horizontal distance of the body were similar. In conclusion, the inferior alveolar nerve should be found in very similar locations on both normal and microsomic sides in low-grade hemifacial microsomic patients.

Adolescent↗
PubMed1996

Bone transport using intramedullary fixation and a single flexible traction cable.

The transfixing wires used in the limb-lengthening and bone-transport procedures described by Ilizarov are the primary source of complications, including infection, restricted joint motion, and pain. In an attempt to eliminate the need for external fixation, a traction cable device was devised to perform a 3-cm bone transport in the canine femur using an interlocking intramedullary rod for fixation. Twelve dogs were divided into 2 groups. Transport began 7 days after osteotomy and continued at either 1 mm per day (n = 6) or 2 mm per day (n = 6). The in vivo peak force, resting force, and stiffness of the transport segment increased throughout distraction to a mean of 150 Newtons, 58 N, and 58 N per millimeter, respectively, at the time of docking. The regenerate and docking sites united in 10 of 12 dogs. Failure of the regenerate associated with deep infection around the rod occurred in 2 animals (17%). Modifications of this technique to reduce the risk of infection are discussed. This study confirms that intramedullary fixation is compatible with distraction osteogenesis and shows that a single traction cable can provide the force necessary for bone transport without transfixing wires in this setting.

Animals↗
PubMedDate not supplied

Treatment of chronic osteomyelitis in children resistant to previous therapy.

Patients admitted to the authors' institution with tibial osteomyelitis between 1978 and 1998 were reviewed. The purpose of this study was to determine the incidence, etiology, treatment, and outcome in chronic pediatric tibial osteomyelitis. The authors describe their treatment of chronic osteomyelitis in children resistant to previous therapeutic modalities. Thirty patients were identified with a mean age of 8.5 years at diagnosis. Mean age at admission was 9.6 years, indicating more than a 1-year duration of disease. Follow-up averaged 2.3 years. Patients underwent 97 procedures, averaging 3.2 procedures per patient. Hospital stay ranged from 2 weeks to 18 months, with an average stay of 4.7 months. Seventy-seven percent of patients were culture-positive, and 78% of positive cultures identified Staphylococcus aureus as the causative pathogen. Eighty percent of patients had a good outcome, 13% had a fair outcome, and there were no poor results. Patients with large tibial defects obtained good results with both tibiofibular synostosis and Ilizarov distraction osteogenesis. The authors describe the only reported group of pediatric patients successfully treated using Ilizarov bone transport for bony tibial defects due to osteomyelitis.

Bone Transplantation↗
PubMed1999

Bone healing of tibial lengthening is delayed by cigarette smoking: study of bone mineral density and torsional strength on rabbits.

OBJECTIVE: We investigated the effect of intermittent cigarette smoke inhalation on the bone healing of tibial lengthening in rabbits. METHODS: Twelve male rabbits were divided into two groups of six animals each. The first group underwent intermittent cigarette smoke inhalation, and the second group did not undergo intermittent cigarette smoke inhalation. Each animal's right tibia was lengthened 5 mm by using an uniplanar lengthening device. Bone mineral density (BMD) study was performed for all of the animals 1 day before operation and 3, 4, 5, and 6 weeks after operation. All of the animals were killed 6 weeks postoperatively for biomechanical testing. RESULTS: By using the preoperative BMD as an internal control, we found that the BMD of the smoke-inhalation group was decreased significantly compared with the non-smoke-inhalation group. The mean %BMD at 3, 4, 5, and 6 weeks were 49.9%, 61.2%, 65.9%, and 71.0%, respectively, in the smoke-inhalation group, whereas the mean %BMD were 54.9%, 71.8%, 76.4%, and 82.0%, respectively, in the non-smoke-inhalation group (two-tailed t test, p > 0.05, p < 0.01, p < 0.01 and p < 0.01 at 3, 4, 5, and 6 weeks, respectively). By using the contralateral nonoperated tibia as internal control, we found that torsional strength of the smoke-inhalation group was decreased significantly compared with the non-smoke-inhalation group. The mean percentage of maximal torque was 63.8% in the smoke-inhalation group, whereas the mean percentage of maximal torque was 77.1% in the non-smoke-inhalation group (two tailed t test, p < 0.01). CONCLUSION: This study suggests that cigarette smoking delays the mineralization during the bone healing process of distraction osteogenesis and, thus, decreases the mechanical strength of the regenerating bone.

Absorptiometry, Photon↗
PubMed2004

Maxillomandibular expansion for the treatment of sleep-disordered breathing: preliminary result.

OBJECTIVE: To assess the outcomes of maxillomandibular expansion (MME) by distraction osteogenesis (DO) for the treatment of sleep-disordered breathing (SDB). METHODS: This was a prospective study of six consecutive patients with SDB. All of the patients have maxillary and mandibular constriction and were treated with MME. Variables examined include age, sex, body mass index (BMI), polysomnographic results (PSG), Epworth Sleepiness Scale (ESS), and the extent of the widening of the maxilla and mandible. RESULTS: All six patients (4 males) completed MME for the treatment of SDB. The mean age was 22.2 +/- 11.4 years. The mean maxillary expansion was 10.3 +/- 3.0 mm, and the mean mandibular expansion was 9.5 +/- 2.9 mm. ESS improved from 10.2 +/- 1.9 to 5 +/- 2.9. The mean apnea/ hypopnea index (AHI) improved from 13.2 +/- 15.6 to 4.5 +/- 5.8 events per hour, and the mean lowest oxygen saturation (LSAT) improved from 88.2 +/- 2.9% to 91.3 +/- 3.3%. The mean esophageal pressure improved from -20 +/- 11.3 cm H2O to -8 +/- 3.6 cm H2O. No complications were encountered, and the follow-up period was 18.1 +/- 9.8 months. CONCLUSION: : The result suggests that MME improves SDB in patients with maxillary and mandibular constriction and can be a valid treatment.

Adolescent↗
PubMed1992

Osseous expansion of the cranial vault by craniotasis.

A study of cranial vault lengthening using a custom expandable fixation-distraction (craniotatic) appliance was performed in the young-adult rabbit model. Ten 24-week-old rabbits underwent circumferential suturectomy plus expansion (expanded group), 10 underwent circumferential suturectomy without expansion (sham control group), and 10 served as normal controls. The appliance was lengthened at a rate of 2.5 mm per week for 5 weeks. Serial lateral cephalometry, comparative dry-skull anthropometric measurements, and histologic examinations were performed. The expanded group demonstrated a significantly longer skull, cranial vault, anterior cranial base, posterior face, and orbit as compared with the control groups (p less than 0.05). Callus bone filled the distracted suturectomy and united the frontofacial complex to the posterior cranium. In conclusion, skull lengthening by distraction osteogenesis is possible in the rabbit model and offers a new technique for future investigation in the treatment of coronal synostosis.

Analysis of Variance↗
PubMed1997

Maxillary-midface distraction in children with cleft lip and palate: a preliminary report.

A miniature system of distraction devices has been employed for maxillary-midface advancement in two children with cleft lip and palate, class III malocclusion, and associated midfacial hypoplasia. The devices are made with commercially available palatal expansion screws linked to rigid fixation plates. A midfacial osteotomy is used, and distraction is begun on the third postoperative day. In the first child, a 7-year-old boy, the midface was distracted 11 mm sagittally and 4 mm inferiorly. In the second patient, a 4 1/2-year-old girl with unilateral cleft lip and palate and midfacial retrusion, an 11-mm distraction was carried out in the vertical and sagittal direction. There were no complications, and none of the devices failed. Maxillary-midfacial distraction osteogenesis to correct severe maxillary-midfacial hypoplasia in children with clefts and other craniofacial disorders permits early intervention with potentially less invasive techniques than are currently available.

Bone Lengthening↗
PubMed2003

Correction of leg-length discrepancy after hip transposition.

Four patients were treated with limb lengthening to correct a leg-length discrepancy that developed after a hip transposition after pelvic resection for sacroma of the pelvis. Three patients had Ewing's sacroma and one patient had osteosarcoma. All patients received chemotherapy; radiotherapy also was administered to the three patients with Ewing's sacroma. Femur lengthening was started at an average of 5.7 years (range, 4.4-6.8 years) after tumor surgery. At the start of elongation, the average age of the patients was 17.3 years (range, 10.3-20.8 years). The average leg-length discrepancy was 10.3 cm (range, 6-12 cm). The average of achieved lengthening was 6.4 cm (range 6-7.5 cm). The average healing index was 32 days (range, 27-40 days) per 1-cm elongation. According to the classification of Paley, two problems and two minor complications were treated by additional interventions. At the final followup, the average functional score was 22 (73%) according to the system of the Musculoskeletal Tumor Society. Leg-length discrepancy after hip transposition can be corrected with distraction osteogenesis. All patients who wore a stiff ankle-foot orthosis before lengthening wore an ordinary shoe lift after lengthening. The problems of the lengthening procedure are similar to the general complication rate of bone lengthening. Because the 5-year survival after resection of a pelvic sarcoma is only 20% to 30%, leg lengthening after hip transposition should be offered only to long-term survivors with at least 5 years event-free survival.

Adolescent↗