"Primary" orthostatic tremor. 10 clinical electrophysiologic observations

Distraction osteogenesis has been shown to be an effective method of lengthening and augmenting endochondral bone. It has also been applied effectively in the reconstruction of the membranous bones of the craniofacial skeleton. With the accumulation of clinical experience in mandibular distraction, the differences between endochondral and membranous bone distraction have become apparent, especially in the limitations of uniplanar distraction for the three-dimensional reconstruction of the deficient mandible. Distraction of the mandible in a single plane cannot satisfy fully the functional and structural requirements of the patient with malocclusion as well as deficiency of the skeletal and soft tissue. This study reports the development and clinical use of a multiplanar mandibular distraction device with the ability to achieve linear distraction (Z-plane or sagittal), angular distraction (Y-plane or vertical), and transverse distraction (X-plane or coronal). The device contains two independent gear arrangements attached to two arms that extend from the central unit. Therefore, the trajectory of the regenerated bone may be changed during the distraction process. The device also allows manipulation of the various planes of movement independent of each other. Furthermore, the rotational points for the multiplanar distraction devices are located at a single point; therefore only a single osteotomy and two pin sites are required. The multiplanar distraction device allows the surgeon to customize and contour the dimensions of the distraction process by controlling the trajectory of the translation of the regenerated bone.     

Brachymetatarsia: congenitally short third and fourth metatarsals treated by distraction lengthening--a case report and literature summary

Brachymetatarsia is an uncommon condition, and when present, it is usually asymptomatic. A case report demonstrating the use of distraction lengthening for symptomatic multiple congenital short metatarsals is presented. A 15-year-old female with congenital short third and fourth metatarsals was treated for painful transfer lesions under the second and fifth metatarsal heads and a secondary hallux valgus deformity. Surgical correction with a chevron osteotomy, soft tissue reconstruction of the second toe, and distraction lengthening of the third and fourth metatarsals was performed. Three years after treatment, the patient has an excellent clinical correction, with no evidence of recurrent transfer lesions. To our knowledge, this is the first report demonstrating the use of distraction lengthening without supplemental bone graft for multiple short metatarsals in a single extremity.     

Distraction effects on muscle. Leg lengthening studied in rabbits

We investigated changes in the anterior tibial muscle during lengthening of the lower leg in rabbits. In 37 rabbits, an osteotomy of the right middle tibia was performed and was fixed by a unilateral external fixator. The rabbits were randomized into 6 groups. In groups 1, 2, and 3 the tibiae were distracted 0.5 mm/day. In groups 1 and 2, the rabbits were killed after 14 and 28 days of distraction, respectively, and in group 3 after 28 days of distraction, followed by 14 days of rest. Groups 1a, 2a, and 3a served as controls. They were treated similarly as groups 1, 2, and 3, but no distraction was performed. Proliferating cell nuclei were labeled with 5-bromo-2-deoxyuridine and were identified by immunohistochemical staining. The weight of the muscle was measured. During bone lengthening the muscle showed signs of growth, as indicated by increasing weight and number of proliferating cell nuclei. This was observed only during lengthening and it ceased when the lengthening was stopped.     

Callus distraction for lengthening of mid-hand and finger stumps in congenital hand abnormalities--personal results and review of the literature

Distraction-lengthening technique is quite useful in a variety of congenital hand deformities with hypoplastic, or primary normal but secondary shortened (constriction ring syndrome) finger rays. It appears that around the age of two years is the earliest practical time to start distraction; certainly distraction and secondary surgical procedures to improve function should be completed before school entry age whenever possible. Between June 1990 and March 1993, nine distraction lengthening procedures (5 thumbs, 1 index, 3 little fingers) in five patients presenting with congenital hand deformities, were carried out. Although restoring length to the finger, lengthening does not provide normal circumference or, of course, interphalangeal joint motion. Amelioration in function seems to be more important than the esthetic gain. Distraction lengthening tolerates only few errors of indication, operative technique, and/or postoperative management. A high compliance of the patient and her/his parents as well as a close follow-up by an experienced surgeon, are mandatory for a good result. A variety of possible complications have been described. Generally, complication risk increases in cases of simultaneous and multiple level lengthening. Provided adequate operative technique and postoperative care, superficial pin infection and fracture in the region of distraction are the major complications. Contrary to adults, sufficient bone formation by distraction is the rule in children. Therefore, the distraction-lengthening technique is preferred to the distraction-interposition technique in the treatment of congenital hand deformities. The latter should only be used as a salvage procedure in the rare cases of insufficient callus formation. Because of the missing growth potential and reduced joint mobility, distraction lengthening is the therapy of second choice when compared to microvascular second toe transplantation.     

Evaluation of the mechanical environment during distraction osteogenesis

Physical forces have been hypothesized to direct the process of bone regeneration during distraction osteogenesis. However, despite significant clinical experience, relatively little is known about how the mechanics of distraction influence bone formation. This study investigated net fixator forces and strains in the distraction callus during bilateral lengthening of tibiae in New Zealand White rabbits. Distractions yielded a classic viscoelastic response with a sharp increase in fixator force, followed immediately by significant relaxation. Tension acting on mesenchymal gap tissue caused by distraction was estimated to reach more than 30 N by the time full lengthening was achieved. Average maximum cyclic strains within the distraction zone during ambulation were estimated to be 14% to 15% and supported by the results of fluoroscopic imaging. Paradigms for fracture healing have hypothesized that such strains are incompatible with new bone formation. The documented clinical success of distraction osteogenesis at stimulating large volumes of new bone suggests that other mechanisms that warrant additional investigation may be at work during distraction.     

Factors affecting callus distraction in limb lengthening

Factors affecting the process of callus distraction in limb lengthening include the type of osteotomy, timing and rate of distraction, and stability of fixation. Thirty-two rabbits were studied to evaluate the reliability of transverse osteotomy and delayed distraction and to examine the appropriate rates of distraction. Rabbit tibiae were osteotomized subperiosteally and were subjected to slow distraction using a rigid monolateral external fixator. There was a ten-day waiting period before distraction. The animals were divided into three groups according to the rate of distraction (0.35 mm/12 hours, 0.7 mm/12 hours, 1.4 mm/12 hours). The process of callus formation was monitored by soft x-ray. The reliability of delayed distraction after transverse osteotomy was demonstrated by microangiographic study. Even though intramedullar vessels were interrupted by osteotomy at surgery, blood circulation recovered during the waiting period before distraction. Bone lengthening was successful when distraction was carried out at rates of 0.35 mm/12 hours or 0.7 mm/12 hours. The callus filling a distraction gap showed a characteristic zone structure, i.e., one central radiolucent zone and two adjacent sclerotic zones. Microangiographic study demonstrated the continuity of blood vessels under these rates of distraction. Based on the results of these experiments and clinical experiences on 180 bone lengthenings, the authors believe that a waiting period after osteotomy is more practical than achieving immediate distraction after uncertain corticotomy.     

Prevention of deformity during limb lengthening

Deformity occurs frequently at the site of distraction during leg lengthening and can add to disability. The elastic and nonelastic displacements have been measured in a model that simulates leg lengthening in the laboratory. Measurements have been made for different fixator systems. The angulation in the vertical plane that occurs during leg lengthening is minimized if the distance between the bone and the fixator bar is kept as small as possible, if three screws are inserted in the proximal and distal bone fragments, and if the peak loads on the fixator are reduced by adjusting the rhythm of distraction. However, even if these precautions are taken, the results show that some fixators designed for leg lengthening will fail and lead to deformity at the osteotomy site. This may occur under the repeated cycles of high loads associated with the rises in soft tissue tension that are known to occur in certain groups of patients. This study suggests that deformity can be prevented by the proper selection of a suitable frame and the adjustment of its configuration to meet the loading requirements.     

Aberrant FHIT transcripts in cancerous and corresponding non-cancerous lesions of the digestive tract

We lengthened seven first metatarsals in four patients with short great toes by callus distraction using an external fixator. Good clinical and cosmetic results were obtained. Bone lengthening is effective in patients with short great toes not only for cosmesis, but also to relieve pain and callosities on the plantar aspect of the second and third metatarsal heads. Excessive lengthening of the first metatarsal resulted in limitation of the range of movement of the metatarsophalangeal joint of the great toe. To prevent this the amount of lengthening should not exceed 40% of the preoperative length of the metatarsal.     

Correction of long term joint contractures of the hand by distraction. A case report

Joint contractures are a common complication of hand trauma. The conventional treatment consists of arthrolysis, tenolysis and occasionally arthrodesis. Frequently, this does not achieve a good result, particularly when there has been a long delay in presentation. Progressive lengthening of a joint by distraction (joint distraction) allows the release of joint contractures even in cases of failure of traditional methods.We present a case of a delayed (20 years) work related traumatic flexion deformity of the PIP joint of the left index and middle fingers. This was the result of a complete division of both flexor tendons of both fingers.The range of movements, both active and passive, was limited to 90/100° in the index finger and 95/100° in the middle finger. Following joint distraction using our lengthening device (Antão™, Portugal) the patient was able to achieve an active and passive range of movements of 10/100° for the PIP joint of the index finger and 40/100° of the middle.This clinical case shows the simplicity and application of our technique for the correction of joint contractures.     

Biomechanical and densitometric bone properties after callus distraction in sheep

Assessment of biomechanical stability of diaphyseal bone lengthened by callus distraction is an unsolved problem. A middiaphyseal corticotomy was performed in the left tibia of 24 sheep. After 7 days, callus distraction was begun at a rate of 0.5 mm every 12 hours for 30 days using a standard unilateral fixator system. Animals were euthanized 4, 8, or 12 weeks after the end of distraction. The lengthened tibia and the contralateral control tibia from each animal were evaluated by radiographic, densitometric (dual energy xray absorptiometry, quantitative computed tomography), and biomechanical (axial compression testing, torsion testing to failure) methods. The bone mineral density and maximum torque for the lengthened tibia were significantly greater in the 8-week group than in the 4-week group. However, the values in the 12-week group were significantly smaller than in the 8-week group. In the lengthened tibias, there was a correlation between the maximum torque and the bone mineral density, and between the maximum torque and the bone density. Bone density measurements are useful prognosticators for the safe removal of external fixators after leg lengthening procedures. By using these methods, clinical fractures after leg lengthening could be avoided in the future.     

Role of saphenous vein surgery in the treatment of venous ulceration

We present 19 ray lengthenings in 14 patients done with a small external fixator. In six cases the thumb was lengthened and in the other 13 cases, other digital rays. The most frequent reason for lengthening was an amputation sustained in a work accident. All the lengthenings were done by an osteotomy and subsequent gradual distraction with a small external fixator. The mean lengthening achieved was 20 mm (range, 0-32). An iliac-crest graft was needed in nine cases, corrective osteotomy in five cases and a deepening of the web in the six cases of thumb lengthening. In five cases an additional technique was needed to achieve bony consolidation. We have analysed the functional results and the ability to perform activities of daily living and resume employment. Although most of the patients had multiples injuries, the results have been very favourable, achieving a very high level of patient satisfaction.     

Histological identification of Lugaro cells in the cat cerebellum

Segmental loss of a peripheral nerve has been a challenging reconstructive problem. Management of the nerve gap has been accomplished classically with nerve grafting. However, autogenous nerve grafts are not always available for bridging large nerve gaps, and clinical results of large nerve cable grafts have been disappointing. Newer techniques concentrate on nerve lengthening with different methods. Tissue expansion of peripheral nerves has been producing promising results. Since the introduction of the Ilizarov external fixator, much attention has turned to limb-lengthening techniques and studies investigating the results of nerve and soft tissues lengthened during the course of this procedure. Primary nerve distraction may be an alternative to nerve elongation, by expansion or nerve grafting to repair the peripheral nerve gap. This study describes a device and a model for peripheral nerve distraction in a rat. Primary nerve distraction will need to be subjected to vigorous studies before clinical application.     

Juvenile xanthogranuloma of the iris with bilateral spontaneous hyphema

Lengthening of the mandible by gradual distraction and ear reconstruction using tissue expanders were performed on nine young patients (6-11 years old) with unilateral hemifacial microsomia. The technique holds promise for reconstruction of ear and mandible at the same time. This is essentially a pilot clinical project. A late follow-up of these patients is necessary.     

Callus formation in the humerus compared with the femur and tibia during limb lengthening

We investigated whether the callus formation in the humerus during the distraction period of limb lengthening proceeds at a higher rate than that in the femur and tibia. Ten achondroplastic patients underwent 3 bilateral humerus, 3 bilateral femur and 4 bilateral tibia lengthenings. To reduce the confounding effect of bone size, we used bone mineral apparent density (BMAD) to compare the three groups; this is a volumetric bone mineral density measurement. BMAD in the distracted callus space was evaluated at 8 weeks after the start of distraction using dual-energy X-ray absorptiometry (mean +/- SD; g/cm3): in the humerus (0.24 +/- 0.08) it was significantly higher than in the tibia (0.10 +/- 0.02), while there was no difference between the humerus and femur (0.35 +/- 0.11). We conclude that the callus formation in the humerus during the distraction period of limb lengthening proceeded at a significantly faster rate than in the tibia, but there was no significant difference between the humerus and femur.     

Effect of methotrexate on distraction osteogenesis

To assess the potential of using distraction osteogenesis to reconstruct bone deficient limbs after limb salvage for musculoskeletal sarcomas, the authors examined the effect of methotrexate on distraction osteogenesis in a rabbit tibial lengthening model. Eighteen rabbits underwent tibial corticotomy and application of a ring external fixator. Rabbits were assigned randomly to one of two groups in which either methotrexate (n = 12) or placebo (n = 6) was administered during a 21-day distraction period. Serum methotrexate levels and complete blood cell counts were monitored during distraction, and radiographs of the tibia were obtained weekly. Half of the animals from each group were sacrificed at the end of distraction, and the remaining animals were sacrificed after 6 weeks of neutral fixation when bone normally bridges the gap. Using methotrexate at serum concentrations similar to those used clinically for the treatment of human osteosarcomas, the authors were unable to show significant radiographic, histologic, or chemical differences in the effect of this antineoplastic drug on distraction osteogenesis in the rabbit model.     

AP-1 and NF-kappaB regulation in rheumatoid arthritis and murine collagen-induced arthritis

Mandibular distraction was performed on 14 children, between September 1991 and December 1997. Their average age was 6.9 years, ranging from 1.5 to 13.5 years. All patients had severe hypoplastic mandibles with retromandibulism. Seven of the children (50%) had respiratory distress due to obstruction of the upper airway before distraction. This resolved in every case. Five patients underwent unilateral and nine bilateral distraction. A total of 23 distractors were used, 15 were applied extraorally and 8 endorally. The average latency time after operation was 2.8 days, but for the past 2 years, distraction was started beginning with the operation. The distraction was increased twice daily for an average of 5.5 weeks, by 0.4 or 0.5 mm each time, depending on the distractor. Computed tomography and ultrasound were used to follow the ossification process in the distraction gap and to measure the lengthening achieved. Subsequent retention time averaged 2.4 weeks. The mandibles were elongated by up to 18 mm (average 9.3 mm) and the respiratory distress symptoms resolved in all patients. Several minor complications which are reported occurred. Six patients were followed up for periods between 3 and 7 years. During this time further growth of the distracted mandibles was recorded.     

Basement membrane of blood vessels during distraction osteogenesis

A canine model of distraction osteogenesis has recently been developed that permitted the evaluation of bone formation and its vascularization during bifocal callotasis. In this model, the authors examined the composition of the blood vessels during distraction osteogenesis of the mandible for laminin and for Type IV collagen, both constituents of the vascular basement membrane. At the fibrous distraction site, at the juncture of the free cortical surface and the regenerated bone, and at the abutting cortical surfaces at the distal margin of the defect, laminin and Type IV collagen were present in all vessels.     

Overdiagnosis of major psychiatric disorders in individuals with substance use disorders and personality disorders: the downside of the Woodruff principle

Major vascular injury can result during use of the Ilizarov technique for lower extremity limb lengthening. Vascular reconstruction may be accomplished while leaving the external fixation ring in place. Continued distraction is made possible by leaving sufficient redundancy in the vascular graft.     

Content and predictors of the ethnic identity of Russian-speaking immigrant adolescents in Finland

Even though osteodistraction has been well established in the extremities, the parameters used in craniofacial distraction have been essentially borrowed from orthopaedic experience. Latency is widely practised but its relevance has not been fully investigated. The purpose of this study was to establish the role of latency in mandibular distraction osteogenesis. Twenty-two growing Wethers sheep were allocated to four experimental groups. Six animals were allocated to each of Groups A, B and C and underwent bilateral mandibular corticotomies and attachment of an external lengthening device. Latent periods of 0, 4 and 7 days respectively were observed prior to beginning distraction. The distraction protocol consisted of a rate of 0.5 mm twice daily for 20 days, followed by a consolidation phase of 20 days after which the sheep were killed. Histology, bone densitometry and 3-point mechanical testing were performed on the harvested mandibles. Group D formed the control group (n = 4). Histologically, the distracted bone exhibited bone formation primarily via intramembranous ossification with scattered islands of cartilage. The regenerated bone had mechanical properties significantly weaker than the undistracted control group (P < 0.05), but between the experimental groups no statistically significant differences were demonstrable either in mechanical strength or DEXA density. These data indicate that a change in latency does not alter the properties of the regenerated bone in mandibular distraction osteogenesis and indeed no latent interval may be necessary at all in craniofacial distraction. This has implications for the duration of device fixation in distraction procedures.     

Distraction osteogenesis for lengthening of the hard palate: Part II. Histological study of the hard and soft palate after distraction

To correct velopharyngeal incompetence, a new treatment concept was proposed in Distraction Osteogenesis for Lengthening of the Hard Palate: Part I (using lengthening of the hard and soft palate by distraction osteogenesis). Cephalometry and computed tomography showed successful elongation of the posterior hard palate with gradual calcification. Here the sequential use of fluorochrome markers (oxytetracycline, xylenol orange, DCAF [2,4-bis-N-N'-dicarboxymethyl aminomethyl fluorescein], and alizarin complexone) during the distraction and retention period is reported together with the histologic investigations using light and laser scan microscopy without prior demineralization. The experimental gap showed de novo osteogenesis in all dogs. The new bone was always in continuity with the original anterior and posterior palatal bone margins. It either bridged the experimental gap fully or left a small central zone of fibrous tissue, in which eventual ossification occurred. Several distinct zones could be distinguished: A small central zone was found with parallel strains of collagen fibers, oriented longitudinally in the direction of the distraction. Next to this zone a layer of undifferentiated mesenchymal precursor cells was seen in direct contact to newly formed bone. The next zone was coarse woven bone, showing a transition to mature lamellar bone through remodeling. No evidence of endochondral bone formation was found, i.e., all dogs showed exclusively intramembranous bone formation. The soft tissues showed no signs of alteration: in particular, there was no necrosis or scar formation. The soft tissues were not thinned but appeared to have followed the longitudinal displacement. In conclusion, gradual distraction osteogenesis of the hard palate could be a possible method for lengthening the palate to treat velopharyngeal incompetence.