What the patients and parents do not tell you-recollections from families following external LeFort III midface distraction

OBJECTIVE

The purpose of this study was to document the experience of patients and parents of patients who had recently undergone LeFort III midface distraction using an external halo-based device.

DESIGN

Cross-sectional study.

SETTING

A craniofacial center in a pediatric tertiary care medical center.

SUBJECTS

Eight children who had undergone midface distraction within 1 year of the interview and their caregivers.

INTERVENTION

Semi-structured interview.

MAIN OUTCOME MEASURE

Transcripts of the interviews were rendered anonymous and analyzed by our multi-disciplinary team. Consistent themes in the subjects' experience during and after midface distraction were identified.

RESULTS

(1) Family participation in the decision to undergo distraction and pre-operative preparation was recognized as valuable, but parents identified that there are inherent limitations; (2) home-care tasks seemed daunting pre-operatively but were easier than expected; (3) discomfort, sleeping, and interaction with peers were considered well accommodated, but feeding was challenging; (4) individualized pre-operative plans for community support was important; (5) parents and patients were impressed by the change in appearance, specifically in the peri-orbital region; (6) access to team members and to parents of patients who had participated in the distraction process was invaluable.

CONCLUSION

External midface distraction is a valuable clinical technique, but requires intensive preparation and support from a multi-disciplinary team. We provide suggestions for consideration by centers initiating and refining patient care plans for this surgery.

Pin-tract infection during limb lengthening using external fixation

We evaluated the incidence of pin-tract infection (PTI) during limb lengthening using external fixation in 88 patients and the effects of infection on final outcomes and incidence of additional procedures. The PTI rate was 96.6%. The rate of half-pin site infection was significantly (P<.05) higher in half-pin fixators (100%) than in hybrid fixators (78%). There was a significantly (P<.05) higher incidence of half-pin site infection (78%) than fine-wire site infection (33%). The rate of additional surgeries for treating PTI was higher for half-pin sites than for fine-wire sites. Three (3.4%) of the 88 cases led to chronic osteomyelitis. Careful insertion and a simple, well-defined, excellent pin-care protocol can minimize PTI.

Distraction osteogenesis for ridge augmentation: prevention and treatment of complications. thirty case reports

Distraction osteogenesis (DO) is the latest addition to the variety of alveolar ridge augmentation procedures used to increase the volume of bone prior to implant placement. Thirty DO procedures were performed in 30 patients using 17 intraosseous and 13 extraosseous devices to augment deficient alveolar ridges. Fifty-five implants placed in the distracted bone were followed for a period of 34 to 60 months after loading. Five implants failed, for a 90.9% success rate. Vertical augmentation ranged from 3.5 to 13.0 mm (average, 7.8 mm). At least one complication was encountered, requiring additional hard or soft tissue surgery, in each of the 30 reported cases. This paper reviews complications encountered in the DO-treated patients, suggesting solutions and measures to prevent these problems.

Morbidity related to "endo-corticotomies" for transpalatal osteodistraction

INTRODUCTION

The objective of this study was to evaluate morbidity arising from transnasal, endoscopically assisted corticotomies for transpalatal osteodistraction. This minimally invasive technique utilizes three 1-cm incisions in the nasal vestibule instead of the classical, two lateral and one medial oral vestibule incisions of 2-3 cm and 1cm long, respectively.

MATERIAL AND METHODS

Fifty-nine patients (33 females and 26 males; age range: 9-50 years, mean 20 years) who underwent surgery in the hub hospital by the senior surgeon were included in a prospective registry. Patients with congenital maxillary hypoplasia were excluded. Difficulties were systematically recorded.

RESULTS

Mean operative time was 68 min (SD: 15 min) when no other procedures were combined with the transpalatal osteodistraction. Ten difficulties unrelated to either the device or oral hygiene were encountered: rhinorrhoea and minor nasal obstruction (1), nasal bleeding with hospital admission (1), periostitis at the piriform aperture that necessitated revision using local anaesthesia (1), periostitis with spontaneous healing (1), postoperative pain (2), dermatitis (1), infraorbital ecchymosis (1), excessive postoperative oedema (1), and prolonged cheek hyperaesthesia (1).

DISCUSSION AND CONCLUSION

Operative time as well as both percentage and nature of complications was similar to those experienced with "open-sky TPD" (transpalatal distraction), with less pronounced oedema and patient surgical threshold decreased.

Vertical distraction of the severely resorbed edentulous mandible: an assessment of treatment outcome

PURPOSE

To assess the treatment outcome (implant survival, surgical complications, patient satisfaction) of vertical distraction of the severely resorbed edentulous mandible.

MATERIALS AND METHODS

Forty-six patients with severe resorption of the edentulous mandible (bone height 5 to 8 mm, median 6 mm) participated in this study. The anterior segment of the mandible was vertically augmented using the Groningen distraction device. One or 2 months after the last day of distraction, 2 implants (n = 92) were placed. Standardized clinical and radiographic assessments were performed annually, and patient satisfaction was scored on a 10-point rating scale (0 = completely dissatisfied; 10 = completely satisfied).

RESULTS

Three implants were lost during the healing phase, but none were lost for the rest of the follow-up period (72 +/- 10.3 months), resulting in an implant survival rate of 97%. One patient developed a fracture of the mandible 3 days after the last day of distraction; it healed uneventfully. The mean mandibular bone resorption during follow-up as measured on radiographs in the midline and distal of the implants was 9.8% +/- 0.6% and 10.2% +/- 0.8%, respectively. In 4 patients radiolucency in the distracted area persisted during the follow-up period. Four patients reported a slight sensory disturbance at the final evaluation visit. All patients functioned well with their prostheses. The mean patient satisfaction score after treatment was 8.1 +/- 1.2.

CONCLUSION

Vertical distraction of the anterior segment of a severely resorbed alveolar ridge of the mandible can provide a proper basis for insertion and osseointegration of endosseous load-bearing implants with good implant survival, few surgical complications, and good patient satisfaction.

Minimizing pin complications when using the rigid external distraction (RED) system for midface distraction

In this review we describe the advantages, complications, and preventive considerations encountered as a result of the use of a halo for distraction of a retrusive nasomaxillary complex. Distraction osteogenesis is a well accepted combined orthodontic-surgical technique used in the treatment of patients with hypoplastic craniofacial components. The rigid external distraction (RED) system is a useful external distraction device for the advancement of severe retrusive maxilla especially in cleft palate patients. However, the addition of this new technique to the surgeon's armamentarium is accompanied by new complications and risks. Review of the literature on complications of the use of halo revealed that most complications are pin related. Complications with the use of RED have mainly included the penetration of intracranial pins. Risk management and preventive considerations propose several procedures to minimize the side effects when using RED: preoperative skull computerized tomography, pediatric neurosurgical consultation, proper pin care during distraction, frequent monitoring of the patient's general condition, proper pin and torque design, and special attention to the removal process of the RED.

Complications associated with distraction osteogenesis for the correction of brachymetatarsia: a review of five procedures

BACKGROUND

Congenital brachymetatarsia is often treated with callus distraction. This technique is associated with a variety of complications. We investigated complications encountered in treatment of brachymetatarsia in four female patients and reviewed adjunctive procedures performed to treat these complications.

METHODS

We reviewed five distraction osteogenesis procedures performed in four female patients with congenital shortening of the fourth metatarsal over a 3-year period. Serial radiographs were obtained weekly until bone consolidation was achieved, at which time the external fixator was removed. Follow-up ranged from 5 to 10 months.

RESULTS

Three patients (four metatarsals) were satisfied with the cosmetic and functional outcomes of their procedure. One patient was dissatisfied with the cosmetic result owing to a short digit from a short proximal phalanx but was completely functional and resumed all of her normal activities. Complications associated with callus distraction were decreased range of motion and stiffness at the metatarsophalangeal joint, flexion deformity of the digit, angulation of the metatarsal, prolonged distraction time due to pain, fracture of the bone callus, pin-site infection, and an undesirable cosmetic appearance due to a short proximal phalanx. Adjunctive procedures were needed in some of these cases and yielded good results.

CONCLUSIONS

Callus distraction is an effective treatment for congenital shortening of the fourth metatarsal, but the procedure is associated with a number of complications. Because most patients proceed with surgery for cosmetic reasons, it is important to present the possible complications and the adjunctive surgical procedures that may be necessary for a desirable outcome.

Complications and relapse in alveolar distraction osteogenesis in partially dentulous patients

Vertical distraction of the alveolar process is an efficient method for augmentation prior to inserting dental implants. In this study, complications of this procedure and relapse of the transport segment were evaluated in partially dentulous patients. Twenty patients underwent distraction by means of extraosseous distractors. The location of the defects was the anterior mandible (4), posterior mandible (4), anterior maxilla (10) and posterior maxilla (2). Bone height was measured on panoramic radiographs preoperatively, after distraction and after implant placement at the mesial and distal point of the implant(s). Mean alveolar distraction was 6.5mm at the mesial point (P<0.001) and 6.1mm at the distal point (P<0.001). The mean relapse at the mesial point was 20% and at the distal point 17% (P<0.05). The intraoperative and postoperative problems encountered were fracture (1) and lingual (4) and palatal (6) displacement of the transport segment. Overall complication rate was 55%. Of all implants placed (n=63) one was lost. Implant success rate was 98%. Distraction seems to be a suitable treatment for vertically deficient alveolar bone, but a relatively high although manageable complication rate must be confronted, including considerable relapse.

Gradual reduction of distal radial malunion using distraction osteogenesis

PURPOSE

To evaluate gradual distraction lengthening or distraction osteogenesis as a technique for treating malunions of the distal radius.

METHODS

Twenty patients with clinical and radiographic evidence of distal radius malunion were treated with osteotomy of the distal radius using distraction osteogenesis. At the follow-up evaluation each patient was evaluated for healing rates, complications, resolution of pain, and radiographic alignment. Surgical treatment consisted of an application of a nonbridging external fixator that could be distracted to correct the deformity. A loosely set screw that connected the distal pins to the fixator served as a hinge and allowed the distal radius to rotate into a corrected position. Gradual distraction via distraction osteogenesis was initiated 1 week after surgery.

RESULTS

Seventeen osteotomies healed uneventfully in an average of 9 weeks. Complications included 9 pin track infections. Two nonunions required bone grafting. One patient inadvertently compressed rather than distracted the fixator, leading to premature healing of the osteotomy. One patient ruptured the extensor pollicis longus. All complications resolved with additional intervention. Overall the patients showed radiographic and symptomatic improvement.

CONCLUSIONS

An external fixator and distraction lengthening through distraction osteogenesis is a viable alternative to plate fixation and bone grafting. In 18 of 20 of our patients, the technique eliminated the need for bone grafting and the need for a second surgical procedure to remove a dorsal plate.

Facial Nerve Paralysis

Distraction osteogenesis is a useful technique in temporomandibular joint reconstruction after gap arthroplasty for ankylosis. We report a case of unilateral facial nerve paralysis during the distraction phase of treatment in a patient with temporomandibular joint ankylosis who was treated with gap arthroplasty and distraction osteogenesis. The clinical course is described and discussed.

The effect of mandibular distraction osteogenesis on the histology and immunohistology of keratinized gingiva

OBJECTIVES

We investigated distracted keratinized epithelium to elucidate any proliferative and degenerated changes and to estimate the stability of the gingival tissues in mandibular distraction osteogenesis in a rabbit model.

STUDY DESIGN

Twenty-two rabbits were subjected to unilateral vertical osteotomy. After a latency period of 4 days, devices were activated 3, 6, and 10 days at a rate of 1 mm/day. We additionally investigated the recovery of the distracted gingiva in consolidation periods for 3 weeks. The animals were examined by histologic and immunohistologic methods using proliferating cell nuclear antigen (PCNA), single-stranded DNA (ssDNA), and keratin.

RESULTS

Atrophy of distracted gingiva was observed characterized by loss of rete ridges, acanthosis, vacuolation in the prickle cell layer, and cleavage of the keratin layer. Proliferating cell nuclear antigen-positive cells and ssDNA-positive cells were observed in the basal and prickle layers, respectively. During consolidation periods, slight recovery of rete ridges, thinning of the keratin layer, and immature epithelial layer was observed.

CONCLUSIONS

Proliferative and degenerated changes occurred to compensate for cell death and distracted space. Thickness of gingival tissues was maintained by high mitotic activity and delay in the rate of cell maturation. Immature epithelial layer was related to sensitive and weak resistance against various stimulating factors, such as cleavage of the keratin layer among distracted gingival tissues.

Treatment of Upper Airway Obstruction in Infants with Micrognathia Using Mandibular Distraction Osteogenesis

Mandibular distraction osteogenesis has become an accepted alternative treatment for infants and children with upper airway obstruction associated with micrognathia. Several reports exist that purport the efficacy of mandibular distraction in these patients, such as preventing tracheostomy or facilitating tracheostomy removal. However, the majority of these studies are retrospective reviews with small cohorts and relatively short-term follow-up. Consequently, the ideal indications, pre- and postoperative evaluation, timing, and treatment are subject to controversy and not currently well established. Significantly less attention has been given to short- and long-term complications of mandibular distraction, such as effects on the developing tooth buds, impact on future mandibular development, and temporomandibular joint abnormalities. This article reviews the basic principles of distraction osteogenesis, summarizes the outcomes of recent literature involving pediatric mandibular distraction including this author's experience, and discusses the known and potential adverse sequelae of mandibular distraction. Before a clearly defined role of mandibular distraction in the treatment of infants with micrognathia-associated upper airway obstruction can be established, additional prospective studies are necessary to delineate its benefits and limitations.

Rapid canine distalization through segmental alveolar distraction osteogenesis

OBJECTIVE

The objectives of this study were to achieve rapid canine distalization by segmental alveolar distraction method in first premolar extraction cases, to examine the changes in the periodontal tissues surrounding canines, to evaluate the displacement of the canine and first molar teeth, to assess the effects of the procedure on the pulpal vitality of the canines, and to determine the amount of root resorption in retracted canines.

MATERIALS AND METHODS

The sample of the study consisted of 20 teeth in eight patients (four females and four males, mean age 18.5 years). Pre- and posttreatment dental casts, panoramic radiographs, and standard periapical radiographs were taken from all patients. An electrical vitality test was applied before and after the distraction procedure and during the follow-up period (6 months after the completion of the procedure). In addition, six periodontal indices were used to examine the health of the periodontal tissues.

RESULTS

The distraction procedure was completed in 12 to 28 days (mean 14.65 +/- 3.49). The anchorage loss ranged from 0 to 3 mm (mean 1.2 +/- 0.83). The distal displacement of the canines ranged from 3 to 8 mm (mean 5.35 +/- 1.22). The canines showed a mean of 9.1 degrees distal tipping, whereas there was no statistically significant change in the axial inclinations of first molars after distraction.

CONCLUSION

We believe that rapid canine distalization by segmental distraction osteogenesis will become a routine protocol and a popular method among orthodontic applications.

Reactivation of trigeminal neuralgia following distraction osteogenesis in an 8-year-old child: report of a unique case

Trigeminal neuralgia is extremely rare in children. No concrete treatment protocols seem to be available for management of this condition in the pediatric population. Although trigeminal neuralgia may achieve remission, the possibility of reactivation of a hitherto quiescent condition cannot be ruled out. We present a case of pediatric trigeminal neuralgia following distraction osteogenesis of the mandible.

Rapid Canine Distalization through Segmental Alveolar Distraction Osteogenesis

OBJECTIVE

The objectives of this study were to achieve rapid canine distalization by segmental alveolar distraction method in first premolar extraction cases, to examine the changes in the periodontal tissues surrounding canines, to evaluate the displacement of the canine and first molar teeth, to assess the effects of the procedure on the pulpal vitality of the canines, and to determine the amount of root resorption in retracted canines.

MATERIALS AND METHODS

The sample of the study consisted of 20 teeth in eight patients (four females and four males, mean age 18.5 years). Pre- and posttreatment dental casts, panoramic radiographs, and standard periapical radiographs were taken from all patients. An electrical vitality test was applied before and after the distraction procedure and during the follow-up period (6 months after the completion of the procedure). In addition, six periodontal indices were used to examine the health of the periodontal tissues.

RESULTS

The distraction procedure was completed in 12 to 28 days (mean 14.65 +/- 3.49). The anchorage loss ranged from 0 to 3 mm (mean 1.2 +/- 0.83). The distal displacement of the canines ranged from 3 to 8 mm (mean 5.35 +/- 1.22). The canines showed a mean of 9.1 degrees distal tipping, whereas there was no statistically significant change in the axial inclinations of first molars after distraction.

CONCLUSION

We believe that rapid canine distalization by segmental distraction osteogenesis will become a routine protocol and a popular method among orthodontic applications.

The humerus is the best place for bone lengthening

The aim of this study was to examine the effectiveness of lengthening the humerus in children and young adults. Between 1984 and 2005, the Orthopaedic Department of Semmelweis University elongated 11 humeri (ten patients) for reasons of congenital hypoplasia (four cases), osteomyelitis (three cases), epiphyseolysis, growth plate closure after irradiation and obstetrical paralysis (one case each). The study cohort consisted of five females and five males, with an average age at the time of surgery of 17.8 years (range: 12-31 years). In every case, the lengthening was performed with a unilateral Wagner fixator. The lengthening protocol was 1 mm distraction daily (callotasis) after a 7-day latency period. The fixator was removed after total bone healing. Plate fixation or bone transplantation was not used. The average rate of lengthening was 6.2 cm (4.5-10.5 cm), and the achieved lengthening was 27% (range: 16-44%). The average healing index was 32 day/cm. One patient who suffered from temporary radial paresis, and temporary flexion contracture of the elbow was regarded as a complication following placement of the fixator. Based on our results, humeral shortening can effectively be treated with the unilateral Wagner fixator. The main difference between the original Wagner method and our approach is that we were able to leave the fixator in the humerus until total bony reconstruction so there was no need for plate fixation or bone transplantation.

Distraction vs remodeling surgery for craniosynostosis

OBJECTS

We designed several distraction devices and applied these instruments in 14 patients with varying types of craniosynostosis. The aim of this report is to clarify the advantages and disadvantages of these surgical methods and to discuss current concepts for the surgical strategy in the treatment of craniosynostosis.

METHODS

From January 2000 to July 2005, 28 patients with craniosynostosis were retrospectively analyzed. Surgical treatment was performed on 14 patients using the distraction method with internal distraction devices that we designed, in which 5 patients had plagiocephaly, 3 brachycephaly, and 6 scaphocephaly. All patients underwent preoperative and postoperative evaluations, which included the patient's neurological state, and three-dimensional CT.

RESULTS

With distraction devices, the time required for the surgery could be shortened almost 3 1/3 h; the bleeding during the surgery was decreased with reduced requirement of more than 200 ml of blood transfusion as compared with remodeling surgery. Postoperatively achieved distraction distances varied from 30.0 to 47.5 mm (mean, 42.99 mm). The average increased volume percent of cranium in distraction surgery group was 20.9% (range, -11.5 to 58.9%) after full distraction.

CONCLUSION

With distraction surgery, satisfactory cranial volume expansion and aesthetically pleasing morphological states were achieved in all cases, and the efficacy was statistically significantly high as compared with remodeling method.

Mandibular symphyseal distraction osteogenesis: review of three techniques

Mandibular symphyseal distraction osteogenesis (MSDO) is an alternative strategy to correct mandibular transverse deficiencies and dental crowding. Only a limited number of practitioners have reported their clinical experience and potential complications of this procedure to widen the mandible in a large case series. This study involved retrospective analysis of 40 patients who underwent mandibular symphyseal distraction osteogenesis. Three different types of distractor were used to widen the mandible: tooth-borne in 21 patients, bone-borne in 5 patients and hybrid (both bone and tooth-borne) in 14 patients. The distraction amount ranged from 7 to 11 mm (mean 7.31 mm). While 39 patients underwent successful mandibular symphyseal distraction, there was one failure. Most of the complications were experienced in bone-borne distractors, such as breakage of the distractor rod, gingival recession, secondary infection and ptosis of the chin. In the light of these findings, it is suggested that a lingually placed tooth-borne hyrax appliance is more suitable and reliable than the other distraction devices. Further larger studies are needed in order to better evaluate the effectiveness of bone-borne or hybrid devices.

Peri-Implant Bone Loss Around Posterior Mandible Dental Implants Placed After Distraction Osteogenesis: Preliminary Findings

BACKGROUND

The present study evaluates implant survival and peri-implant bone loss around posterior mandible dental implants placed at sites of distraction osteogenesis.

METHODS

On removal of the distraction devices, 34 dental implants were inserted into 14 posterior mandible sites in 10 healthy, non-smoking female patients. Prosthetic treatment was performed 4 months after implant placement using fixed implant prostheses. After 6 to 16.5 months, periapical radiographs were taken and evaluated for peri-implant bone loss and radiolucency. The distance between the implant margin and the first visible bone-implant contact was measured on the mesial and distal aspects of the implants using imaging software. Radiographic dimensional distortion was corrected as a function of the known true dimension of the implant.

RESULTS

Of the 34 implants placed, two (5.9%) failed to integrate at reentry surgery. Both were replaced and restored during the course of the study so that a total of 34 implants was followed for 12.1 +/- 3.8 months post-restoration and 16.1 +/- 3.8 months post-insertion. Mean loss of marginal bone height was 2.6 +/- 1.0 mm. During the follow-up period, radiolucent lines along the implant surface were absent.

CONCLUSIONS

The mean peri-implant bone loss in areas of alveolar bone distraction was 1.9 mm/year. A high implant survival rate was observed.

Complications in Alveolar Distraction Osteogenesis: A Clinical Investigation

PURPOSE

The purpose of this study was to evaluate distraction osteogenesis for reconstruction of vertically deficient alveolar ridges and to investigate the occurrence of complications during treatment and the effect of these complications on the final outcome.

PATIENTS AND METHODS

The study included 23 patients who underwent a total of 29 distraction procedures. Two types of distractors were used: intraosseous and juxtaosseous. All of the patients were submitted to the same distraction protocol. The complications occurring during treatment were classified as 1) intraoperative, 2) postoperative, 3) during distraction and consolidation, and 4) postdistraction.

RESULTS

The prevalence of cases with complications was 41.37% intraoperative, 24.13% postoperative, 65.51% during distraction and consolidation, and 58.62% postdistraction. Because many complications coincided in some patients, the overall prevalence throughout the treatment was 79.31% of cases; 3.44% of the complications jeopardized subsequent implant placement.

CONCLUSIONS

Although a high frequency of complications was encountered, severe complications were rare. Most of the complications had simple solutions, and most did not jeopardize the final outcome. Distraction osteogenesis is a viable option for treating vertical alveolar bone defects.

Histological evaluation of the temporomandibular joint after bilateral vertical ramus mandibular distraction in a canine model

The aim of this pilot study was to histologically evaluate the effect of bilateral vertical mandibular distraction osteogenesis (DO) on the temporomandibular joint (TMJ) in a canine model. Eight male beagle dogs underwent DO, with the placement of single-vector internal distractors. One unoperated animal served as control. After a latency period of 7 days, distraction was performed at a rate of 1 mm a day for an average of 12 days. The animals were divided into two groups (n = 4) and sacrificed after one or two months of consolidation. Eighteen TMJs were prepared for histological evaluation. Control TMJs surfaces were smooth, with no irregularities and trabecular bone was thick and multiply connected. In the one-month group, thinning of the trabecular bone was evident. The trabeculae were long, not multiply connected, parallel to each other and perpendicular to the articular surface. Although overall fibrous-cartilaginous tissues covering the TMJs were maintained with no signs of degenerative changes, one condyle from the one-month group had depressions and erosions of the fibro-cartilage layer and subcortical bone. In the two-month group, overall bone and cartilage architecture was more similar to the control specimens. This study indicates that, in the short term, gross changes can occur in the TMJ after bilateral mandibular vertical ramus distraction. These changes seem to be a process of biological adaptation to the pressure and functional changes secondary to surgery and distraction. However, long-term studies are needed to confirm whether the changes are completely reversible.

Condylar mineralization following mandibular distraction in rats

The impact of mandibular distraction on condyles is poorly understood. To examine how condylar mineralization is affected, we performed distraction in 128 one-month-old rapidly and 126 three-month-old slowly growing rats. The rate of distraction was 0.0 mm (sham), 0.2 mm (slow), 0.4 mm (moderate), or 0.6 mm (rapid). From 7 to 9 rats from each rate (n = 29-32) were killed at 4 time periods (D6, D10, D24, and D38) following osteotomy. Calcein and alizarin were injected 6 and 3 days, respectively, prior to death. Methacrylate-embedded sagittal condylar sections were examined under epifluorescence, and mineral apposition rates were measured. Results indicated that: (1) rapidly growing rats showed higher mineral apposition rates (p < 0.01-0.001) than did slowly growing rats; (2) mineral apposition rates were lower in distracted sides at all times in rapidly growing rats (p < 0.05-0.01), while this side-dependency was seen only at D24 in slowly growing rats (p < 0.05); and (3) distraction rates had little effect on mineral apposition rates. Thus, mandibular distraction decreases condylar mineral apposition rates, but only in rapidly growing rats, which is related to surgery and its functional consequences, not to the distraction rate.

Bone defect formation during implant placement following alveolar distraction

PURPOSE

This retrospective study was designed to evaluate the volume of hard tissue generated at the time of implant placement in distracted alveolar bone.

MATERIALS AND METHODS

All patients who underwent distraction osteogenesis between 2000 and 2003 were included. The preoperative bone height, amount of distraction performed, and presence or absence of complications affecting implant placement were recorded. The augmentation achieved was correlated with insufficient bone formation using the Spearman correlation and the Fisher exact test.

RESULTS

The study included 43 implants placed in 17 cases of alveolar distraction. Of the 34 implants placed in bone augmented by 4.5 to 6.5 mm, bone defects were observed with 12. All 9 implants placed in ridges augmented by 7 to 10.5 mm demonstrated a bone defect. The "defect" and "no-defect" implant groups differed significantly with respect to preoperative bone height and amount of distraction performed (P < .001 for both). Significantly more defects were formed in bone augmented by > 25% compared to bone augmented by < 25% (P < .001).

CONCLUSIONS

When considering distraction osteogenesis, augmentation of up to 25% of the initial bone height seems more predictable and less likely to be associated with complications at the time of implant placement. In distractions greater than 25% of the original height, additional treatment should be considered.