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Sci Rep ; 11(1): 14727, 2021 07 19.
Article En | MEDLINE | ID: mdl-34282216

The work aimed to evaluate the effectiveness of the developed distraction system based on the rod external monolateral fixation mechanisms by comparing it with the classical technique of long tubular bones distraction based on the circular multi-axial system. The study included patients with a genetically confirmed diagnosis of achondroplasia. The experimental group consisted of 14 patients who underwent surgical limb lengthening by the rod monolateral external fixator with a distraction system developed by the authors. The lengthening was performed on 28 segments of tubular bones. The majority of the experimental group patients achieved the lengthening value close to the planned one and the deformation correction. The fixation period was averagely 83.8 ± 3.7 days, the regenerate length was 8.5 ± 0.6 cm, and the mechanical strength of the distraction regenerate was 10.3° ± 2.18°. The rod external fixator with a control distraction system developed by the authors has small dimensions and low weight of the external supporting elements of high durability. It is reported to provide a good psychological tolerance of the treatment process and significantly outperforms the circular multi-axis system. Considering the aforementioned, the proposed apparatus can grant good orthopedic care to patients with achondroplasia.

Achondroplasia/surgery , External Fixators , Fracture Fixation , Osteogenesis, Distraction , Achondroplasia/pathology , Adolescent , Arm/surgery , Child , Child, Preschool , Equipment Design , Female , Femur/surgery , Fracture Fixation/instrumentation , Fracture Fixation/methods , Humans , Male , Osteogenesis, Distraction/instrumentation , Osteogenesis, Distraction/methods , Osteotomy/instrumentation , Osteotomy/methods , Postoperative Complications/etiology , Treatment Outcome
J Pediatr Orthop ; 41(6): 356-361, 2021 Jul 01.
Article En | MEDLINE | ID: mdl-34096549

BACKGROUND: Lengthening of long bones by distraction osteogenesis is now possible using intramedullary lengthening nails. Constraints of bone size, medullary canal obstruction, and the presence of an open physis are contraindications in skeletally immature patients. We present a technique describing the "off-label" use of a magnetic lengthening nail placed extramedullary and in retrograde manner, for lengthening of the femur in skeletally immature patients. METHODS: A retrospective review of 5 skeletally immature patients with significant length discrepancy of the femur are presented along with a description of the surgical technique. Data collected included age, sex, date of surgery, diagnosis, presence of associated deformities, the magnitude of length discrepancy, the amount of length gained, the amount of time to achieve full weight-bearing, the time to hardware removal, and any complications. RESULTS: There were 5 patients (3 females). The mean age was 7.2±2.7 years (4 to 10 y). The mean limb length discrepancy was 6.5±3.7 cm (3.5 to 11 cm). A mean length of 3.46±0.4 cm (3.1 to 4 cm) was achieved which represents 12.9±1.8% (10.32 to 13.47%) of the bone length. The time taken to achieve full weight-bearing ambulation was 89.2±19.3 days (60 to 109 d) or 12.7 weeks. All hardware was removed 247.6±215.6 days (99 to 628 d) after surgery. Patients were followed up for a mean duration of 19.2 months (11 to 30 mo). No supplemental fixation was required and no complications were noted. Acute deformity correction was also performed at the time of surgery in 2 patients who had distal femur valgus deformity. CONCLUSIONS: Retrograde extramedullary lengthening of the femur is an option that should be considered for limb length equalization in skeletally immature patients. It avoids the inconvenience of external fixation and can be used to simultaneously correct deformities of the distal femur. Although the total amount of length gained is modest, we believe it is a promising limb lengthening technique that merits further investigation. LEVEL OF EVIDENCE: Level III.

Bone Nails , Femur/surgery , Leg Length Inequality/surgery , Osteogenesis, Distraction/methods , Child , Child, Preschool , Female , Femur/abnormalities , Humans , Magnetics , Male , Osteogenesis, Distraction/instrumentation , Retrospective Studies , Treatment Outcome , Walking , Weight-Bearing
Clin Plast Surg ; 48(3): 363-373, 2021 Jul.
Article En | MEDLINE | ID: mdl-34051891

Pierre Robin sequence is defined by the clinical triad: mandibular hypoplasia, glossoptosis, and airway obstruction. Mandibular distraction osteogenesis (MDO) is a standard treatment of Robin sequence associated with severe airway obstruction and is the only intervention that directly corrects the underlying anatomic pathologic condition. Compared with tongue-lip adhesion, MDO has demonstrated more success in treating airway obstruction in infants with Pierre Robin sequence, including patients with syndromic diagnoses and concomitant anomalies. This article provides a current, comprehensive review of neonatal mandibular distraction and offers treatment guidelines based on a combined surgical experience of more than 400 patients.

Mandible/surgery , Orthognathic Surgical Procedures/methods , Osteogenesis, Distraction/methods , Pierre Robin Syndrome/surgery , Airway Obstruction/surgery , Humans , Infant, Newborn , Osteogenesis, Distraction/adverse effects , Osteogenesis, Distraction/instrumentation , Postoperative Complications , Treatment Outcome
Clin Plast Surg ; 48(3): 375-389, 2021 Jul.
Article En | MEDLINE | ID: mdl-34051892

Phenotypic severity dictates the timing and type of surgical intervention required. Mandibular distraction in children without respiratory and feeding difficulties remains controversial with regard to long-term mandibular growth outcomes and reducing surgical burden. Early mandibular distraction does not obviate secondary orthognathic surgery at skeletal maturity; it provides improved functional, aesthetic, and psychosocial outcomes, at least in the short term. Costochondral rib grafting for Pruzansky type IIB and III mandibles can produce reliable results, especially when combined with subsequent mandibular distraction. Secondary 2-jaw orthognathic surgery plus genioplasty at skeletal maturity benefits from improved bone volume from prior mandibular distraction.

Bone Transplantation , Goldenhar Syndrome/surgery , Mandible/surgery , Orthognathic Surgical Procedures/methods , Osteogenesis, Distraction/methods , Algorithms , Bone Transplantation/methods , Child , Child, Preschool , Genioplasty , Goldenhar Syndrome/diagnostic imaging , Humans , Infant, Newborn , Mandibular Advancement/methods , Phenotype , Tomography, X-Ray Computed
Clin Plast Surg ; 48(3): 391-405, 2021 Jul.
Article En | MEDLINE | ID: mdl-34051893

Distraction osteogenesis is a viable treatment option for patients with a cleft associated with severe maxillary retrusion. A rigid external distraction device and a hybrid internal maxillary distractor have been used to advance the maxilla allowing for predictable and stable results. These techniques can be applied by itself or as an adjunct to traditional orthognathic procedures. The technical aspects are presented. These procedures tend to be simpler and demonstrate great stability compared to traditional surgical methods. The reasons for stability are discussed.

Cleft Lip/surgery , Cleft Palate/surgery , Maxilla/surgery , Osteogenesis, Distraction/instrumentation , Osteotomy, Le Fort/instrumentation , Female , Humans , Male , Maxilla/abnormalities , Osteogenesis, Distraction/methods , Osteotomy, Le Fort/methods
Clin Plast Surg ; 48(3): 407-417, 2021 Jul.
Article En | MEDLINE | ID: mdl-34051894

Maxillary hypoplasia is a commonly seen dentofacial anomaly in patients with cleft lip and palate after surgical repair of the cleft anomaly. To facilitate large horizontal movements of the maxilla, distraction osteogenesis is used to slowly stretch the soft tissue envelope with the skeletal advancement preventing tissue recoil and skeletal relapse. Internal distraction devices have the advantage of reducing the amount of physical and psychological stress placed on patients, families, and caregivers. The technique has been successful in producing stable results for large advancements of the facial skeleton when compared with conventional Le Fort I advancement and fixation of the maxilla.

Cleft Lip/surgery , Cleft Palate/surgery , Maxilla/surgery , Osteogenesis, Distraction/instrumentation , Osteotomy, Le Fort/instrumentation , Female , Humans , Male , Maxilla/abnormalities , Osteogenesis, Distraction/methods , Osteotomy, Le Fort/methods
Clin Plast Surg ; 48(3): 419-429, 2021 Jul.
Article En | MEDLINE | ID: mdl-34051895

Alveolar distraction osteogenesis (ADO) has been used for the reconstruction of atrophic alveolus for decades. The advantage of this technique is that it augments the bone and soft tissues together, creating a better alveolar platform for subsequent surgeries and dental rehabilitation. It is especially useful in patients with large and/or complex alveolar clefts for which approximating the alveolar segments reduces the size of the bony cleft and associated fistula. Displacement of the transported segment is the most frequently encountered complication of ADO but can be managed by constructing case-specific distractors.

Alveolar Bone Grafting , Alveolar Process/surgery , Alveoloplasty/methods , Cleft Palate/surgery , Osteogenesis, Distraction/methods , Adolescent , Alveolar Process/abnormalities , Humans , Male , Orthodontics, Corrective/methods , Osteogenesis, Distraction/instrumentation , Young Adult
Clin Plast Surg ; 48(3): 431-444, 2021 Jul.
Article En | MEDLINE | ID: mdl-34051896

Treacher Collins syndrome (TCS) is a genetic disorder that presents with a variety of craniofacial deformities. One classic feature of TCS is a steep, counterclockwise rotation of the occlusal plane, and microretrognathia with bony deficiencies in both the body and ramus of the mandible. This morphology commonly necessitates reconstruction by the craniofacial surgeon. This article discusses strategies and considerations for surgically correcting the mandibular deformity associated with TCS using mandibular distraction osteogenesis and other related techniques. The proper implementation of these techniques can yield excellent results that greatly improve quality of life in this challenging patient population.

Mandible/surgery , Mandibular Advancement/methods , Mandibulofacial Dysostosis/surgery , Osteogenesis, Distraction/methods , Humans , Orthognathic Surgical Procedures/methods , Quality of Life
Clin Plast Surg ; 48(3): 445-454, 2021 Jul.
Article En | MEDLINE | ID: mdl-34051897

Anatomic studies have identified that patients with Treacher Collins syndrome and some cases of bilateral craniofacial microsomia are characterized by multilevel airway obstruction as a result of hypoplasia and clockwise rotation of the maxillomandibular complex. Patients often remain tracheostomy-dependent despite multiple airway surgeries. Counterclockwise craniofacial distraction osteogenesis aims to correct the facial skeletal deformity and expand the upper airway volume by rotating the subcranial complex en bloc around the nasofrontal junction. Early results have demonstrated significant increases in the nasopharyngeal and oropharyngeal airway volumes with successful decannulation in a majority of patients who have undergone this operation.

Goldenhar Syndrome/surgery , Mandibulofacial Dysostosis/surgery , Osteogenesis, Distraction/methods , Airway Obstruction/etiology , Airway Obstruction/surgery , Facial Bones/abnormalities , Facial Bones/surgery , Female , Humans , Male , Mandible/surgery , Tracheostomy
Clin Plast Surg ; 48(3): 455-471, 2021 Jul.
Article En | MEDLINE | ID: mdl-34051898

Posterior cranial vault distraction osteogenesis is a powerful, reliable, low-morbidity method to achieve intracranial expansion. It is particularly useful in treating turribrachycephaly seen in syndromic craniosynostosis, allowing for gradual expansion of the bone while stretching the soft tissues over several weeks allowing greater volumetric expansion than conventional techniques. Posterior cranial vault distraction osteogenesis constitutes a more gradual remodeling modality, with infrequent complications. As a first step in intracranial expansion, it preserves the frontal cranium for future frontofacial procedures. A drawback is the need for a second surgery to remove the device, and this must be taken into account during counseling.

Craniosynostoses/surgery , Osteogenesis, Distraction/methods , Skull/surgery , Abnormalities, Multiple/surgery , Female , Humans , Intracranial Pressure , Male
Clin Plast Surg ; 48(3): 473-485, 2021 Jul.
Article En | MEDLINE | ID: mdl-34051899

The Le Fort III advancement was first described in 1950 and has since become a key technique in the armamentarium of craniofacial surgeons. The application of distraction osteogenesis to the craniofacial skeleton has allowed for large movements to be performed safely in young patients. This technique is valuable for correcting exorbitism, airway obstruction owing to midface retrusion, and class III malocclusion. It can be performed with either an external distractor or internal distractors. Although serious complications have been reported, these occur rarely when performed by experienced providers.

Craniosynostoses/surgery , Osteogenesis, Distraction/methods , Osteotomy, Le Fort/methods , Airway Obstruction/etiology , Airway Obstruction/surgery , Female , Humans , Male , Orthognathic Surgical Procedures/methods , Osteotomy, Le Fort/adverse effects , Osteotomy, Le Fort/instrumentation , Preoperative Care
Clin Plast Surg ; 48(3): 487-496, 2021 Jul.
Article En | MEDLINE | ID: mdl-34051900

Severe midface hypoplasia is often managed by Le Fort III distraction. Le Fort II distraction with zygomatic repositioning is a modification of the Le Fort III distraction operation aimed to correct abnormal facial ratios of patients with greater central than lateral midface deficiency. The operation starts with Le Fort III osteotomies and is followed by separation and fixation of bilateral zygomas. The central nasomaxillary Le Fort II segment is then distracted to achieve independent movements of the central and lateral midface. The Le Fort II zygomatic repositioning operation has become our procedure of choice for patients with Apert facial dysmorphology.

Acrocephalosyndactylia/surgery , Osteotomy, Le Fort/methods , Zygoma/surgery , Facial Bones/abnormalities , Facial Bones/surgery , Female , Humans , Male , Maxilla/surgery , Osteogenesis, Distraction/methods
Clin Plast Surg ; 48(3): 497-506, 2021 Jul.
Article En | MEDLINE | ID: mdl-34051901

The introduction of distraction osteogenesis to frontofacial monobloc advancement has increased the safety of the procedure. One hundred forty-seven patients with syndromic craniosynostosis underwent frontofacial monobloc advancement using 4 internal distractors. Twenty-five were aged 18 months or less. Ten patients presented with a tracheostomy, 5 (50%) were decannulated after surgery, and 3 others (30%) required an additional intervention before decannulation. Six patients required the addition of a transfacial pin and external traction. Very early frontofacial monobloc with 4 internal distractors is a safe and effective treatment to protect the ophthalmic, neurologic, and respiratory functions in infants with severe syndromic craniosynostosis.

Craniofacial Dysostosis/surgery , Osteogenesis, Distraction/methods , Craniofacial Dysostosis/complications , Craniosynostoses/complications , Craniosynostoses/surgery , Facial Bones/abnormalities , Facial Bones/surgery , Female , Humans , Infant , Male , Occlusal Splints , Osteogenesis, Distraction/instrumentation , Sleep Apnea Syndromes/etiology , Sleep Apnea Syndromes/surgery , Tracheostomy
Clin Plast Surg ; 48(3): 507-519, 2021 Jul.
Article En | MEDLINE | ID: mdl-34051902

Monobloc and bipartition advancement by external distraction plays a major role in the treatment of syndromic craniosynostosis. They can reverse the associated facial deformity and play a role in the management of ocular exposure, intracranial hypertension, and upper airway obstruction. Facial bipartition distraction corrects the intrinsic facial deformities of Apert syndrome. Both procedures are associated with relatively high complication rates principally related to ascending infection and persistent cerebrospinal fluid leaks. Modern perioperative management has resulted in a significant decline in complications. External distractors allow fine tuning of distraction vectors and improve outcome but are less well tolerated than internal distractors.

Acrocephalosyndactylia/surgery , Craniofacial Dysostosis/surgery , Osteogenesis, Distraction/methods , Facial Bones/abnormalities , Facial Bones/surgery , Female , Humans , Male , Osteogenesis, Distraction/adverse effects , Osteogenesis, Distraction/instrumentation
Clin Plast Surg ; 48(3): 521-529, 2021 Jul.
Article En | MEDLINE | ID: mdl-34051903

Monobloc and facial bipartition combined with distraction osteogenesis (MFBDO) has gained popularity over the past several years as a treatment of syndromic craniosynostosis, in part because this surgical technique effectively removes many stigmatic clinical features associated with the syndromic face. The objective of this study is to detail the surgical planning used to achieve medialization of the orbits and describe the authors' experience using MFBDO to destigmatize the syndromic face. By using MFBDO, hypertelorism, vertical orbital dystopia, and downslanting of the palpebral fissure were surgically corrected in all patients, thereby destigmatizing the syndromic face.

Acrocephalosyndactylia/surgery , Craniofacial Dysostosis/surgery , Orthognathic Surgical Procedures/methods , Osteogenesis, Distraction/methods , Adult , Child , Face/surgery , Female , Humans , Male , Osteogenesis, Distraction/instrumentation
Clin Plast Surg ; 48(3): 531-541, 2021 Jul.
Article En | MEDLINE | ID: mdl-34051904

A combined surgical and orthodontic approach to midface and mandibular distraction optimizes stability and outcomes. Orthodontic considerations include proper planning of the distraction vector, appropriate device use, and thorough follow-up through the consolidation and postoperative period. The dental occlusion must be managed throughout treatment in order to achieve ideal results.

Mandible/surgery , Maxilla/surgery , Orthognathic Surgical Procedures/methods , Osteogenesis, Distraction/methods , Humans , Male , Micrognathism/surgery , Orthognathic Surgical Procedures/instrumentation , Osteogenesis, Distraction/instrumentation
J Orthop Traumatol ; 22(1): 14, 2021 Mar 18.
Article En | MEDLINE | ID: mdl-33738638

BACKGROUND: Femoral shaft fractures are usually treated with nailing using a traction table and a perineal post, but this may occasionally result in various groin-related complications, including pudendal nerve neurapraxia. Although most of them are transient, complication rates of up to 26% are reported. Recently, postless distraction technique has been described for elective hip arthroscopy. In this study we compared post and postless distraction technique in femoral shaft fracture nailing in terms of (1) quality of reduction, (2) outcome, and (3) complications. METHODS: We reviewed 50 patients treated with postless distraction nailing technique for femoral shaft fractures and compared them with our historical case series (95 patients). The following data were collected for all patients: age, gender, weight, height, diagnoses (fractures were classified according to the 2018 revision of AO classification), type and size of nail surgical timing, Trendelenburg angles during surgery, quality of reduction according to Baumgaertner and Thoresen classifications, Modified Harris Hip Scores at 6 months, and perineal complications. RESULTS: Median age was 53 years, and median weight was 70 kg (range 50-103 kg). We found no significant difference in terms of quality of reduction (72 versus 74% "excellent" reduction for subtrochanteric fractures, while 81 versus 79% "excellent" reduction for femoral shaft fractures) and functional outcomes (Modified Harris Hip Score 74 versus 79). One patient in the control group had a failure of the fixation, and one patient in the postless group had a deep infection. Two patients in the control group reported pudendal nerve neurapraxia for 4 months, while none reported complication linked to the postless technique. CONCLUSIONS: Our results using the postless distraction technique show a sufficient distraction to allow reduction and internal fixation of the femoral fracture with a standard femoral nail. LEVEL OF EVIDENCE: IV.

Bone Nails , Femoral Fractures/surgery , Fracture Fixation, Intramedullary/methods , Hip Fractures/surgery , Osteogenesis, Distraction/methods , Adult , Female , Femoral Fractures/diagnostic imaging , Fracture Fixation, Intramedullary/instrumentation , Hip Fractures/diagnostic imaging , Humans , Internal Fixators , Male , Middle Aged , Retrospective Studies
Mol Med Rep ; 23(5)2021 05.
Article En | MEDLINE | ID: mdl-33760114

Steroid­induced avascular necrosis of the femoral head (SANFH) is a common orthopaedic disease that is difficult to treat. The present study investigated the effects of total flavonoids of Rhizoma drynariae (TFRD) on SANFH and explored its underlying mechanisms. The SANFH rat model was induced by intramuscular injection of lipopolysaccharides and methylprednisolone. Osteoblasts were isolated from the calvariae of neonatal rats and then cultured with dexamethasone (Dex). TFRD was used in vitro and in vivo, respectively. Haematoxylin and eosin staining was used to assess the pathological changes in the femoral head. Terminal deoxynucleotidyl transferase­mediated deoxyuridine triphosphate nick end labelling assay and flow cytometry were conducted to detect apoptosis of osteoblasts. The 2',7'­dichlorofluorescein­diacetate staining method was used to detect reactive oxygen species (ROS) levels in osteoblasts and the 3­(4,5­dimethylthiazol­2­yl)­2,5­diphenyltetrazolium bromide assay was used to detect osteoblast proliferation. The expression of caspase­3, Bax, Bcl­2, VEGF, runt­related transcription factor 2 (RUNX2), osteoprotegerin (OPG), osteocalcin (OCN), receptor activator of nuclear factor κB ligand (RANKL) and phosphoinositide 3­kinase (PI3K)/AKT pathway related­proteins were detected via western blotting. It was found that TFRD reduced the pathological changes, inhibited apoptosis, increased the expression of VEGF, RUNX2, OPG and OCN, decreased RANKL expression and activated the PI3K/AKT pathway in SANFH rats. TFRD promoted proliferation, inhibited apoptosis and reduced ROS levels by activating the PI3K/AKT pathway in osteoblasts. In conclusion, TFRD protected against SANFH in a rat model. In addition, TFRD protected osteoblasts from Dex­induced damage through the PI3K/AKT pathway. The findings of the present study may contribute to find an effective treatment for the management of SANFH.

Flavonoids/pharmacology , Osteonecrosis/drug therapy , Plant Extracts/pharmacology , Polypodiaceae/chemistry , Animals , Cell Proliferation/drug effects , Core Binding Factor Alpha 1 Subunit/genetics , Disease Models, Animal , Femur Head/pathology , Flavonoids/chemistry , Gene Expression Regulation/drug effects , Humans , Male , Osteoblasts/drug effects , Osteogenesis, Distraction/methods , Osteonecrosis/chemically induced , Osteonecrosis/pathology , Osteoprotegerin/genetics , Phosphatidylinositol 3-Kinases/genetics , Plant Extracts/chemistry , Proto-Oncogene Proteins c-akt/genetics , RANK Ligand/genetics , Rats , Reactive Oxygen Species/metabolism , Signal Transduction/drug effects , Steroids/adverse effects
J Pediatr Orthop ; 41(4): e328-e336, 2021 Apr 01.
Article En | MEDLINE | ID: mdl-33560708

PURPOSE: The purpose of this study was to analyze the long-term results of humeral lengthening in achondroplastic patients and make suggestions on the most appropriate surgical technique to improve patient outcomes. METHODS: Fifty-four humeral lengthening procedures performed in 27 achondroplastic patients were reviewed. Elongations were performed by means of callotasis with unilateral external fixation. Inclusion criteria were: achondroplastic patients under 17 years without prior arm operations and minimum follow-up of 36 months. RESULTS: Fifty humeri in 25 patients (13 men and 12 women), aged between 9 and 17 years, met the inclusion criteria. Mean humeral lengthening was 8.82 cm (range: 5 to 10.5 cm), which represented an elongation of 54.80% (range: 46% to 63%) of the original length. The healing index was 0.91 months (range: 0.72 to 1.4 mo) per centimeter gained. Shoulder and elbow range of motion and stability were preserved in 47 limbs. Noncomplicated cases consistently experienced a significant functional improvement in the performance of activities of daily living such as putting on footwear and personal hygiene. Short-term complications included 11 pin-tract infections, 1 radial nerve neuropraxia, and 1 failure of the regenerated bone formation. None of these complications prevented from completion of treatment. Long-term complications included 2 cases of nonunion, 3 elbow flexion contractures, and 2 cases of psychological dissatisfaction, all of them in 4 patients. Factors associated with long-term complications were intraoperative fragment displacement and distal humeral osteotomy. No fractures of the regenerated bone were identified in the long term. CONCLUSIONS: Callotasis with unilateral external fixation is a reliable and well-tolerated procedure for humeral lengthening in achondroplastic patients, with an acceptable complication rate. Guided fixator placement and a proximal humeral osteotomy are strongly recommended technical tips as they may help prevent complications and improve outcomes. LEVEL OF EVIDENCE: Level IV-case series.

Achondroplasia/surgery , Humerus/growth & development , Humerus/surgery , Activities of Daily Living , Adolescent , Child , Elbow Joint/physiopathology , External Fixators/adverse effects , Female , Humans , Male , Osteogenesis, Distraction/adverse effects , Osteogenesis, Distraction/methods , Osteotomy/adverse effects , Range of Motion, Articular , Shoulder Joint/physiopathology , Treatment Outcome , Wound Healing
Orthop Surg ; 13(2): 623-631, 2021 Apr.
Article En | MEDLINE | ID: mdl-33565272

OBJECTIVES: To observe the changes in the concentrations of circulating peripheral blood mesenchymal stem cells (PBMSCs) in Sprague Dawley (SD) rats and explore the pattern of changes in PBMSCs during the process of distraction osteogenesis. METHODS: SD rats were randomly divided into the osteotomy with lengthening group (lengthening group), the osteotomy without lengthening group (osteotomy group), and the blank control group (control group). Each group included 24 rats. Percutaneous pinning with external fixation of the left femur was carried out in lengthening group and osteotomy group, but control group received no surgical treatment. On day 5 after operation, continuous traction was carried out at a rate of 0.25 mm/d in lengthening group, while no traction was carried out in osteotomy group. Peripheral blood was collected from all rats on days 1, 3, 7, and 16 after the start of traction. PBMSCs were isolated by density gradient centrifugation. CD105, CD34, and CD45 were selected as cell surface markers. The concentration of PBMSCs was detected by flow cytometry and compared between groups at different time points. X-ray films were taken during and after the operation to observe whether the osteotomy end was pulled and the growth and mineralization of the new bone in the osteogenic area of the femur. Color ultrasound was used to monitor the width of the distraction space, the formation of new bone, and the blood supply of soft tissue around the distraction. RESULTS: All rats were able to tolerate the operation well, and the external fixation was firm and reliable. X-ray showed that, in lengthening group, the distraction space of femur gradually widened and new bone gradually formed in the distraction space; after 8 weeks, the samples were taken out, which showed that the new bone tissue in the lengthened area healed well. In osteotomy group, the average healing time of osteotomy was (7.12 ± 0.78) weeks. Ultrasonic examination showed that after the end of traction, the high echo callus shadow was seen in the traction space, and the blood flow signal was obviously rich at an earlier stage. In lengthening group and osteotomy group, the average concentrations of PBMSCs (3.02% ± 0.87% vs 2.95% ± 0.74%, respectively) were significantly increased in the early stage after osteotomy, and the average concentrations of PBMSCs on days 3, 7, and 16 after the start of traction were 5.34% ± 1.13% vs 3.28% ± 1.22%; 6.41% ± 1.05% vs 3.16% ± 0.92%; and 5.94% ± 1.23% vs 1.48% ± 0.52%, respectively. The concentration of PBMSCs in peripheral blood of lengthening group and osteotomy group was the same at osteotomy stage, and the difference between the two groups was not statistically significant (P > 0.05). After that, compared with lengthening group, the concentration of PBMSCs in osteotomy group gradually decreased and maintained at a certain level; the difference between the two groups was statistically significant (P < 0.05). CONCLUSIONS: Distraction osteogenesis of femur can significantly increase PBMSCs in SD rats and participate in the process of bone formation.

External Fixators , Femur/surgery , Mesenchymal Stem Cells/metabolism , Osteogenesis, Distraction/methods , Osteotomy/methods , Animals , Disease Models, Animal , Male , Rats , Rats, Sprague-Dawley