Trans-sutural Distraction Osteogenesis Research Articles

Objective and subjective evaluation of the efficacy of trans-sutural distraction osteogenesis: A correlation analysis between computed tomography measurements and FACE-Q scores

Previous studies on the efficacy of trans-sutural distraction osteogenesis (TSDO) to treat midface hypoplasia caused by cleft lip and palate (CLP) have mainly focused on objective measurements while ignoring the subjective feelings of patients. This study aimed to analyse the changes in and correlation between computed tomography (CT) measurements and FACE-Q scores in patients who underwent TSDO by performing a comprehensive evaluation from both objective and subjective perspectives. This retrospective study included 25 patients with an average age of 10.7 years who had midface hypoplasia caused by CLP and underwent TSDO between August 2018 and December 2022. The average follow-up time was 18.8 ± 7.7 months. Facial morphology and CT measurements, including A-CR, N-A⊥HR, the SNA angle and the L-ZA, indicated significant improvements in midface concavity (all p < 0.0001). All FACE-Q scores (except for facial function) exhibited a significant increase. The ΔA-CR, ΔN-A⊥HR, and ΔSNA angle were strongly correlated with specific aspects of the FACE-Q-Appearance items, including the ΔFACE-Q-Appearance of the cheeks (all p < 0.0001), the ΔFACE-Q-Appearance of the face (all p < 0.0001), the ΔFACE-Q-Appearance of the jaws (all p < 0.01), the ΔSatisfaction with decision (all p < 0.0001) and the ΔSatisfaction with outcome (all p < 0.001). However, the ΔA-CR, ΔN-A⊥HR, and ΔSNA were weakly correlated with other FACE-Q-Health-related quality of life and function items. These findings suggest that both CT findings and FACE-Q scores have their own emphases and advantages. It is necessary to establish an integrated curative effect evaluation model that combines FACE-Q scores with CT measurements to evaluate both the physical health and psychological status of patients.

The Effect of Trans-Sutural Distraction Osteogenesis on Nasal Bone, Nasal Septum, and Nasal Airway in the Treatment for Midfacial Hypoplasia in Growing Patients.

The purposes of this study were to analyze the effect of trans-sutural distraction osteogenesis (TSDO) on nasal bone, nasal septum, and nasal airway in the treatment of midfacial hypoplasia. A total of 29 growing patients with midfacial hypoplasia who underwent TSDO by a single surgeon were enrolled. The 3-dimensional measurement of nasal bone and nasal septum changes was performed using computed tomography (CT) images obtained preoperatively (T0) and postoperatively (T1). One patient was selected to establish 3-dimensional finite element models to simulate the characteristics of nasal airflow field before and after traction. After traction, the nasal bone moved forward significantly (P<0.01). The septal deviation angle was lower than that before traction (14.43±4.70 versus 16.86 ±4.59 degrees) (P<0.01). The length of the anterior and posterior margin of the vomer increased by 21.4% (P<0.01) and 27.6% (P<0.01), respectively, after TSDO. The length of the posterior margin of the perpendicular plate of ethmoid increased (P<0.05). The length of the posterior inferior and the posterior superior margin of the nasal septum cartilage increased (P<0.01) after traction. The cross-sectional area of nasal airway on the deviated side of nasal septum increased by 23.0% after traction (P<0.05). The analysis of nasal airflow field showed that the pressure and velocity of nasal airflow and the nasal resistance decreased. In conclusion, TSDO can promote the growth of the midface, especially nasal septum, and increase the nasal space. Furthermore, TSDO is conductive to improve nasal septum deviation and decrease nasal airway resistance.

Bone-targeted bortezomib increases bone formation within Calvarial trans-sutural distraction osteogenesis.

The high rate of relapse in craniofacial disharmony treatment via trans-sutural distraction osteogenesis (TSDO) is due to the failure to form a stable bone bridge in the suture gap. Bisphosphonates (BP) have a high propensity to localize to hydroxyapatite in the bone matrix and are commonly used as targeting ligands for local delivery of therapeutics into bone microenvironment. Bone-targeted Bortezomib (BP-Btz) is chemosynthetic by linking Btz (Bortezomib) to a BP residue and could target bone tissue to promote osteoblast differentiation and inhibit osteoclastogenesis. Here, suture-derived mesenchymal stem cells (SuSCs) and osteoclasts were treated with Btz and BP-Btz. Aforesaid drugs were injected locally into the sagittal sutures to explore their effects in TSDO. Further, pharmacological properties of BP-Btz in the suture expansion model were assessed by fluorescent BP analogs and levels of total ubiquitinated (Ub)-proteins. The results showed that BP-Btz could stimulate osteogenic differentiation of SuSCs, bind to bone matrix and inhibit osteoclastogenesis. Biological effects of BP-Btz were similar with those of Btz in osteoblast differentiation and osteoclastogenesis inhibition in vitro. Activated bone metabolism were detected after 14 days in the sagittal suture expansion model. Increased osteoid area, remarkably decreased osteoclast surface and enhanced osteogenesis were detected in vivo after treatment with BP-Btz. Green fluorescence signal detection and pharmacodynamic studies revealed that BP-Btz bound to suture edge, released Btz in remodeling conditions, had a higher local concentration and sustained longer than free Btz. This study delineated the clinical potential of bone-targeted Btz conjugate as an efficacious strategy to promote trans-sutural distraction osteogenesis.

Effect of Bone-Borne Trans -Sutural Distraction Osteogenesis Therapy on the Cranial Base of Children With Midfacial Hypoplasia Due to Cleft Lip and Palate.

Bone-borne trans -sutural distraction osteogenesis (TSDO) is widely used to treat midfacial hypoplasia in children with cleft lip and palate; however, its effects on the cranial base are still poorly understood. The authors aimed to study morphological changes in the cranial base after TSDO. Pre and postoperative computed tomography (CT) images of cleft lip and palate children with midfacial skeleton dysplasia who underwent TSDO were collected retrospectively, and their corresponding 3-dimensional models were measured. Results showed no significant change in the length of the anterior or posterior cranial fossa, but the length of the middle cranial fossa increased significantly. The anterior cranial base rotated upward with the sella turcica at the center, whereas the cranial base angle increased. The sphenoid bone exhibited morphological changes. Post-TSDO, the lateral plate of the pterygoid process increased in length. The angle of the 2 lateral plates of the pterygoid process, the greater wings of the sphenoid bone, and the smaller wings of the sphenoid bone decreased. Posterior inclination of the pterygoid process increased. Mean volume of the sphenoidal sinus increased postoperatively compared with the preoperative volume. Apparent changes in the cranial base after TSDO are primarily in the middle cranial fossa, manifesting as an increase in the sphenoid bone body length, expansion of the sphenoidal sinus volume, growth of the pterygoid process forward and downward, a decrease in the angle of both the greater and smaller wings of the sphenoid bone, and an increase in the posterior inclination of the pterygoid process.

Application of trans-sutural distraction osteogenesis based on an optical surgical navigation system to correct midfacial dysplasia

Midfacial hypoplasia is a common maxillofacial deformity in patients with cleft lip and palate, which requires surgical treatment. However, trans-sutural distraction osteogenesis (TSDO) remains some disadvantages, including difficulty in accurate location of surgical path, prolonged operation time, and excess surgical bleeding. This study aimed to evaluate the application of an optical surgical navigation system (OSNS) developed for TSDO. Six consecutive patients with midfacial hypoplasia who required TSDO were included in the study. Preoperatively, a head computed tomography was performed, and the data were imported into Mimics software (version: 20.0.0.691, Materialise Inc, Belgium) to design a three-dimensional simulation of the surgical approach. TSDO was performed with the use of OSNS. The accuracy and results of the procedure were initially evaluated by comparing the preoperative and postoperative periods. The patients included five boys and one girl, with an average age of 10 years; five with postoperative cleft lip and palate, and one without combined cleft lip and palate. The surgical procedure was successful, with a postoperative follow-up of 4–5 months. All patients demonstrated good treatment results without complications. In conclusioin, OSNS-assisted TSDO can noninvasively correct midfacial dysplasia, improve surgical precision, reduce bleeding and obtain better clinical results. OSNS can guide the TSDO safely and effectively.

Suture Cells in a Mechanical Stretching Niche: Critical Contributors to Trans-sutural Distraction Osteogenesis.

Trans-sutural distraction osteogenesis has been proposed as an alternative technique of craniofacial remodelling surgery for craniosynostosis correction. Many studies have defined the contribution of a series of biological events to distraction osteogenesis, such as changes in gene expression, changes in suture cell behaviour and changes in suture collagen fibre characteristics. However, few studies have elucidated the systematic molecular and cellular mechanisms of trans-sutural distraction osteogenesis, and no study has highlighted the contribution of cell-cell or cell-matrix interactions with respect to the whole expansion process to date. Therefore, it is difficult to translate largely primary mechanistic insights into clinical applications and optimize the clinical outcome of trans-sutural distraction osteogenesis. In this review, we carefully summarize in detail the literature related to the effects of mechanical stretching on osteoblasts, endothelial cells, fibroblasts, immune cells (macrophages and T cells), mesenchymal stem cells and collagen fibres in sutures during the distraction osteogenesis process. We also briefly review the contribution of cell-cell or cell-matrix interactions to bone regeneration at the osteogenic suture frontfrom a comprehensive viewpoint.

Sutural fibroblasts exhibit the function of vascular endothelial cells upon mechanical strain

Midfacial hypoplasia is a type of facial dysplasia. The technique of trans-sutural distraction osteogenesis promotes midface growth so as to ameliorate this symptom. In the process of distraction osteogenesis, the fiber matrix in the suture acts as a mechanical sensor. Compared with osteogenesis, the formation of collagen fibers by fibroblasts is significant in the early stage of sutural distraction. However the transformation of fibroblasts during sutural bone formation induced by tensile force is poorly characterized. Here, we used single-cell RNA sequencing to define the cell classification of the zygomatic maxillary suture and the changes of cell clusters in the suture before and after seven-day distraction. We identified twenty-nine cell subsets spanning monocyte/macrophages, neutrophils, red blood cells, B cells and fibroblasts. Compared with the control group, Monocle analysis revealed the emergence of a unique fibroblast subset (Cdh5+, Col4a1+, Fat1−, and Acta2−) (cluster 27) that expressed vascular endothelial cell genes within the distracted zygomatic maxillary suture. We constructed the differentiation trajectories of the fibroblast population (cluster 23, 27) in the suture before and after distraction. In addition, we clarified that a subset of fibroblasts (cluster 27) lost expression of Fat1, an upregulator of the Hippo pathway, and upregulated Cyr61, a downstream gene of the Hippo pathway, during the distraction process. Further enrichment analysis suggests that cells of the new subset (cluster 27) are undergoing conversion of their identity into a vascular endothelial cell-like state in response to mechanical stimulation, associated with upregulation of angiogenesis genes along the single-cell trajectory. Further immunofluorescence staining confirmed this phenomenon. A combined general transcriptome RNA sequencing data analysis demonstrated that the fibroblasts expressed a number of extracellular matrix-related genes under mechanical strain. These data together provide a new view of the role of fibroblasts in tension-induced sutural angiogenesis via interaction with the Hippo pathway.

Polarized M2 macrophages induced by mechanical stretching modulate bone regeneration of the craniofacial suture for midfacial hypoplasia treatment.

The underlying mechanism of the trans-sutural distraction osteogenesis (TSDO) technique as an effective treatment that improves the symptoms of midfacial hypoplasia syndromes is not clearly understood. Increasing findings in the orthopedics field indicate that macrophages are mechanically sensitive and their phenotypes can respond to mechanical cues. However, how macrophages respond to mechanical stretching and consequently influence osteoblast differentiation of suture-derived stem cells (SuSCs) remains unclear, particularly during the TSDO process. In the present study, we established a TSDO rat model to determine whether and how macrophages were polarized in response to stretching and consequently affected bone regeneration of the suture frontal edge. Notably, after performing immunofluorescence, RNA-sequencing, and micro-computed tomography, it was demonstrated that macrophages are first recruited by various chemokines factors and polarized to the M2 phenotype upon optimal stretching. The latter in turn regulates SuSC activity and facilitates bone regeneration in sutures. Moreover, when the activated M2 macrophages were suppressed by pharmacological manipulation, new bone microarchitecture could rarely be detected under mechanical stretching and the expansion of the sutures was clear. Additionally, macrophages achieved M2 polarization in response to the optimal mechanical stretching (10%, 0.5Hz) and strongly facilitated SuSC osteogenic differentiation and human umbilical vein endothelial cell angiogenesis using an indirect co-culture system in vitro. Collectively, this study revealed the mechanical stimulation-immune response-bone regeneration axis and clarified at least in part how sutures achieve bone regeneration in response to mechanical force.

Influence of Bone-Borne Trans-Sutural Distraction Osteogenesis Therapy on the Hard Palate of Growing Children With Cleft Lip and Palate.

The efficacy of trans-sutural distraction osteogenesis therapy (TSDO) in treating midfacial hypoplasia in children with cleft lip and palate has been confirmed. However, few studies have reported that changes occur in the palate after TSDO treatment. To study the effect of TSDO on palatal morphology and its relative position in the craniofacial region, we retrospectively collected and measured the computed tomography images of 29 growing children with cleft lip and palate and midfacial hypoplasia, before and after TSDO. The results showed that the length and height of the palate did not change significantly, but the width and arch length increased, and the anterior area was more pronounced than the posterior area, with the median palatine suture still centered without obvious deviation. This suggests lateral palate growth after distraction, most likely around the median palatine suture. The distance from the palate to the cranial base also increased after distraction, and the anterior nasal spine moved forward, whereas the palate rotated by an average of 10.04° downward from the center of the anterior nasal spine. The increasing distance between the palate and cranial base may result from the growth of the nasal bone or the skull base. The oropharyngeal airway volume was also increased by an average of 2256.36 mm3, which may be beneficial to children's ventilatory function. In conclusion, TSDO therapy has influence on patients' palatal morphology and position, which should be considered before surgery.

Hydroxyapatite Nanoparticles Facilitate Osteoblast Differentiation and Bone Formation Within Sagittal Suture During Expansion in Rats.

BackgroundThe potential of relapse of craniofacial disharmony after trans-sutural distraction osteogenesis is high due to the failure to produce a stable bone bridge in the suture gap. The aim of this study is to evaluate whether hydroxyapatite nanoparticles (nHAP) have the effect of promoting osteoblast differentiation of suture-derived stem cells (SuSCs) and bone formation in sagittal suture during expansion.MethodsSuSCs were isolated from sagittal sutures and exposed to various concentrations of nHAP (0, 25, 50, and 100 μg mL−1) to determine the optimal concentration of nHAP in osteoblast differentiation via performing Western Blotting and RT-qPCR. Twenty 4-week-old male Sprague–Dawley rats were randomly assigned into 4 groups: SHAM (sham-surgery), distraction, ACS (absorbable collagen sponge) and ACS+nHAP groups. In the ACS and ACS+nHAP groups, saline solution and nHAP suspended in a saline solution were delivered by ACS placed across the sagittal suture, respectively. In the latter three groups, the suture was expanded for 14 days by 50 g of constant force via a W shape expansion device. Suture gap area, bone volume fraction (BV/TV) and bone mineral density (BMD) of sagittal sutures were assessed via micro-CT, while the mechanical properties of sagittal sutures were evaluated via nanoindentation test. The efficacy of nHAP on bone formation in sagittal suture was also evaluated via BMP-2 immunohistochemistry staining.ResultsThe expression of osteoblast related genes and proteins induced by 25μg mL−1 nHAP were significantly higher than the other groups in vitro (p<0.05). Furthermore, treating with 25μg mL−1 nHAP in vivo, the suture gap area was significantly reduced when compared with the distraction group. Correspondingly, the BV/TV, BMD, hardness and modulus of sagittal sutures were significantly increased in the ACS+nHAP group (p<0.05).ConclusionThe 25μg mL−1 dose of nHAP delivered by ACS can facilitate bone formation into the sagittal suture during expansion via inducing osteoblast differentiation of SuSCs.

Imaging study of midface growth with bone-borne trans-sutural distraction osteogenesis therapy in growing cleft lip and palate patients

Trans-sutural distraction osteogenesis (TSDO) promotes midface growth in growing cleft lip and palate (CLP) patients with midfacial hypoplasia. The superficial skeletal changes after therapy revealed rotation advancement of the midfacial skeleton associated with differential displacement in each segment, but reports rarely focus on the changes of internal structures, including circummaxillary sutures, the maxillary tuberosity and the maxillary sinus, which may play a crucial role during this process. This study evaluated the computed tomographic (CT) images of 26 growing CLP patients who received bone-borne TSDO therapy. The results revealed that the most prominent new bone formation occurred in the pterygomaxillary suture and pushed the P-point forward. The maxillary first molar exhibited significantly greater advancement compared with the P-point due to the growth of the maxillary tuberosity. The contribution ratio values of the advancement of the maxillary tuberosity and P-point to the maxillary first molar were 26% and 74%, respectively, in UCLP and 25% and 75%, respectively, in BCLP. Furthermore, the maxillary sinus volume was also significantly increased. In conclusion, midface growth with bone-borne TSDO therapy depends on both secondary displacement promoted by sutural bone formation mainly in the pterygomaxillary suture and primary displacement by growth of the maxillary tuberosity and maxillary sinus volume.

Rigid External Distraction with Intranasal Bone-borne Traction Hooks for Midfacial Hypoplasia

Rigid external distraction is currently performed to correct cases of severe maxillary hypoplasia. As an improvement of this technique, we propose the use of an intranasal bone-borne traction hook. This study is a retrospective chart review of the intranasal bone-borne traction hooks used in the treatment of severe maxillary hypoplasia. There were 110 patients treated with the hooks from 2005 to 2017. The maximum traction force was 7.75 kg, and there were few complications encountered during distraction. There were 76 patients who had the hooks removed under local anaesthesia. A cephalometric analysis was conducted in 56 patients. The average advancement of A-point was 9.9 ± 4.2 mm, 8.4 ± 2.5 mm, 11.0 ± 3.7 mm, 17.9 ± 4.4 mm for the trans-sutural distraction osteogenesis (DO), maxillary anterior segment DO, Le Fort I osteotomy DO and Le Fort III/II osteotomy DO, respectively. The average changes of sella-nasion-point A (SNA) were 8.89 ± 4.30 degrees, 8.21 ± 3.17 degrees, 10.49 ± 3.26 degrees, and 15.10 ± 4.00 degrees, respectively. The A point-nasion-B point (ANB) also showed increases in all procedures with P < 0.001. In conclusion, this technique sufficiently advances the midface and ensures the scars are concealed in the nasal base. The traction hook can bear a large traction force, causes minimal complications and is easily removed.

A New Way to Accelerate the Distraction of the Transpalatal Suture in Growing Dogs Using Recombinant Human Bone Morphogenetic Protein-2

The purpose of this study was to evaluate the administration of recombinant human bone morphogenetic protein-2 (rhBMP-2) on trans-sutural distraction osteogenesis (TSDO) of the transverse palatal suture in growing dogs. A total of 36 growing dogs were used in this study. The experimental animals were treated with different elastic force and rhBMP-2. The bone regeneration was determined with X-ray, histology, and clinical evaluation. The computed values underwent statistical analyses using analysis of variance. The maxillary complex was most noticeably advanced with an applied elastic force of 600 g (22.4 ± 5.0 mm) and 800 g + rhBMP-2 (24 ± 5.1 mm). Immunohistochemical staining showed that the expression of bone morphogenetic protein-2 and bone morphogenetic protein-4 varied with different elastic force. These changes were statistically significant when 600 g and 800 g + rhBMP-2 were applied within 2 weeks of distraction when compared with controls (P < .05). The results of this study suggest that TSDO in the growing dog should be safe and well tolerated when inducing bony lengthening of the maxilla. rhBMP-2 plays an important role in bone regeneration using TSDO.

The Total Calvarial Transsutural Distraction Osteogenesis for 26 Children with Slit Ventricle, Craniosynostosis, or Microcephaly After Shunt Operation

Among shunt complications, the postshunt slit ventricle (PSSV) and the postshunt craniosynostosis (PSCS) may be managed by shunt valve upgrade and/or cranial expansion surgery. Here, we analyzed 26 children with PSSV, PSCS, or microcephaly who received simple generalized cranial expansion (ie, total calvarial transsutural distraction osteogenesis [TC-TSuDO]). Among 254 children with shunt surgery, 26 children received TC-TSuDO. These 26 children included 14 with PSSV, 4 with PSCS, and 8 with both PSSV and PSCS. The mean age of patients who underwent shunt procedures was 8.2 ± 10.6 months, and the mean time interval fromshunt surgery to TC-TSuDO was 26.8 ± 29.5 months. The mean age of children at the time of TC-TSuDO was 33.3± 30.2 months. We analyzed head circumferences, lumbar puncture pressures, development status, operative factors, and postoperative complications. The mean preoperative head circumference was-2.1 ± 1.9, which increased to-1.4 ± 2.1 (P < 0.001) postsurgically. The mean preoperative lumbar puncture pressure was 26.2 ± 10.7 cm H2O which decreased to 11.9 ± 3.5 cm H2O (P < 0.001) after surgery. The mean operation time was 138 ± 66 minutes. The mean intensive care unit stay was 0.27 ± 0.53 days. There were no mortalities but 2 patients suffered from distractor malfunction and 1 patient showed wound discharge. We suggest that postshunt complications such as PSSV or PSCS, especially those that are accompanied by increased intracranial pressure or postshunt microcephaly, may be managed for patients with TC-TSuDO, which has been shown to be safe, simple, and effective.

Changes in the Zygomaticomaxillary Suture During Aging.

Trans-sutural distraction osteogenesis (TSDO) has been successfully used to correct midfacial hypoplasia in growing patients for years. The effects of TSDO, however, remain difficult to predict in adult patients. The aim of this study was to determine the biologic basis for the age-related increase in difficulty of performing TSDO. A total of 45 male Sprague Dawley (SD) rats were obtained in 3 age groups: 4 weeks old (4W, N = 15), 3 months old (3M, N = 15), and 13 months old (13M, N = 15). The zygomaticomaxillary sutures (ZMS) were dissected, and their morphology was evaluated by histology and micro-computed tomography (micro-CT). Quantitative real-time polymerase chain reaction of the ZMS and blood samples taken from the abdominal aorta were also used to assess the effects of age at the molecular level. Compared with the 4W rats, the number of fibroblasts in the ZMS was decreased, the bone plate adjacent to the ZMS was thicker, and the texture was denser in the 13M rats. Micro-computed tomography analysis showed the density of the ZMS was significantly increased in the 13M group (P < 0.05). The density ratio of the ZMS to the adjacent bone was increased from 0.14:1 in the 4M group to 0.54:1 in the 13M group. The gene expression of osteocalcin (OC) was significantly lower at 13M than at 3M (P < 0.05). The OC and alkaline phosphatase (ALP) serum levels were significantly lower at 13M than at 4W (P < 0.05). During aging, the decreased osteogenesis activity both systemically and locally may be the biologic effect that limits the application of TSDO in older patients.

Transsutural distraction osteogenesis for 285 children with craniosynostosis: a single-institution experience.

OBJECT Although distraction osteogenesis (DO) requires a secondary procedure in the surgical correction of craniosynostosis, it is relatively simple, requires less transfusion, results in a shorter intensive care unit stay, and is quite safe. Because of these positive factors, various DO techniques have been developed. However, there is disagreement regarding the superiority of DO. The authors reported on a new DO technique, transsutural DO (TSDO), 6 years ago that was performed in 23 patients over a period of 6 months, and it continues to be used at the present time. In this paper the authors report the results of TSDO performed in 285 patients with craniosynostosis over a period of 6 years at a single institution. METHODS TSDO consists of a simple suturectomy of the pathological suture followed by direct distraction of the suturectomy site only. Types of TSDO conducted included sagittal TSDO in 95 patients, bicoronal in 14, unilateral coronal in 57, lambdoid in 26, metopic in 13, multiple in 19, syndromic in 33, and secondary in 28. The mean age (± SD) of the patients was 19.4 ± 23.0 months, and mean follow-up was 39.5 ± 21.0 months. RESULTS The mean operating time was 115 ± 43 minutes, and mean anesthesia time was 218 ± 56 minutes. The mean transfusion volume of red blood cell components was 48 ± 58 ml, and mean transfusion volume of fresh-frozen plasma was 19 ± 35 ml. Total transfusion volume was significantly less in infants younger than 12 months of age and in children with lower lumbar puncture pressures (p < 0.05). Complications included 1 (0.4%) death from postoperative acute pneumonia after a distractor removal operation and 23 (8%) surgical morbidities comprising 10 revisions (3.5%) and 13 early removals of distracters (4.6%). CONCLUSIONS TSDO is a simple, effective, and safe method to use for treating all types of craniosynostosis. Some morbidity was experienced in this study, but it may be attributed to the learning curve of the technique.

Three-dimensional quantitative evaluation of midfacial skeletal changes after trans-sutural distraction osteogenesis for midfacial hypoplasia in growing patients with cleft lip and palate.

Trans-sutural distraction osteogenesis (TSDO) is an alternative method for the early treatment of midfacial hypoplasia in growing patients with cleft lip and palate (CLP). The purpose of this study was to analyze three-dimensional (3D) midfacial skeletal changes after TSDO and to explore the mechanism in this process. All patients with nonsyndromic CLP who underwent bone-borne TSDO for midfacial hypoplasia from 2005 to 2014 were reviewed in this retrospective study. 3D morphological and quantitative measurement analyses were performed to evaluate midfacial skeletal changes by superimposition of preoperative and postoperative computed tomographic images. Twenty-six patients with mean age of 11.5 years met the inclusion criteria. The 3D morphological findings exhibited the most significant suture stress changes at the pterygomaxillary suture area, with obvious bone generation in all patients. The whole midfacial skeleton had progressively increased advancement in a craniocaudal direction along the midface segment, associated with morphological changes in skeleton itself. The 3D quantitative measurement findings showed differential advancement of each landmark at the maxillary alveolar, zygomatic bone, orbital rim, and nasal bone, which was consistent with morphological findings. TSDO allows rotation advancement of the midfacial skeleton to achieve occlusal correction and facial harmony through the mechanism of both suture remodeling and bone remodeling.

The Total Calvarial Remodeling with Transsutural Distraction Osteogenesis of 21 Cases of Craniosynostosis: New, Efficient, Safe and Natural Method in Craniosynostosis Surgery

Introduction: The majority of the present distraction osteogenesis techniques involve local site expansion that only produces localized decompression and affords limited decompression and cosmetic results. We designed a new surgical procedure, total calvarial transsutural distraction osteogenesis (TSuDO). Methods: We performed total calvarial TSuDO surgical procedures in 21 children. The total calvarial TSuDO method consisted of suturectomy and distraction for the sagittal, bicoronal and bilambdoid sutures. Results: The mean surgery duration was 110 ± 16 min, the mean transfusion volume was 38 ± 45 ml, an average 4.1 ± 0.4 distractors were applied with a mean latency period of 3.3 ± 0.9 days. The mean activation period was 45 ± 18 days with a consolidation period of 54 ± 23 days. There were 3 complication cases of early removal of the distractors: 1 boy with transient 6th cranial nerve palsy accompanied by fever and 2 children with mild pus discharge from the distractor sites. Preoperative lumbar puncture pressures decreased significantly after distractor removal secondary to surgery (p < 0.001). The preoperative cranium size increased significantly (p < 0.001). Conclusion: Total calvarial TSuDO is a simple and safe procedure that may produce wide generalized decompression and good cranial configurations that most closely resemble normal skulls.

Transsutural Distraction Osteogenesis Applied to Maxillary Complex With New Internalized Distraction Device

The purposes of this study were to evaluate the effects of transsutural distraction osteogenesis applied to the maxillary complex with a new internalized distraction device and to analyze the long-term osteogenesis outcome. Three-month-old beagle dogs were treated with a self-designed internalized distractor. The feasibility was evaluated, and the effects of the maxillary growth were measured using radiography and computed tomography (CT). The regenerated bone was examined with micro-CT, biomechanical testing, and histology 1 year after the distraction. The experimental group showed significantly larger forward displacement of maxillary during the distraction. One year after the distraction, the micro-CT showed more incompact structure and bone volume/total volume was significantly less in the experimental group. Biomechanical testing also showed a significantly lower yield but with no difference in stiffness. Histologic staining found osteoclasts deposited in the region of the suture and osteoblasts on the bone surface. The immunohistochemical staining of osteoprotegrin and receptor activator of nuclear factor-κ B ligand showed evidence of expression in suture area components and osteocytes with no difference between the groups. Transsutural distraction osteogenesis using an internalized distractor with skull anchorage demonstrated feasibility. It is expected that this device may provide new thoughts in developing an appropriate appliance for clinical use in young patients with midfacial hypoplasia. Moreover, the long-term osteogenesis analysis findings suggest that the metabolism of sutural area still remained active, which enhanced our understanding of bone remodeling in the sutural area to manage maxillary relapse after transsutural distraction osteogenesis.

Transsutural Distraction and Tissue Regeneration of the Midfacial Skeleton: Experimental Studies in Growing Dogs

Objective : The purpose of this study was to evaluate the effect of different mechanical forces on the expansion of the palatine suture using transsutural distraction osteogenesis. Methods : A total of 48 dogs were used in this study. The experimental groups were treated with a custom-designed internal distractor. Bone regeneration was determined with x-rays and histology. The computed values underwent statistical analyses using analysis of variance. Results : The maxillary complex was most noticeably advanced with an applied mechanical force of 600 g (20.15 ± 1.36 mm), compared with forces of 400 g (19.88 ± 1.41 mm) and 800 g (2.24 ± 0.93 mm). Immunohistochemical staining showed that the expression of bone morphogenetic protein-2 and bone morphogenetic protein-4 fluctuated with different mechanical forces. These changes were statistically significant when 600 g of force was applied within 30 days of distraction (P < .05). Conclusions : Transsutural distraction osteogenesis in the growing dog should be safe and well tolerated in inducing bony lengthening of the maxilla, and the optimal force is 600 × g. Bone morphogenetic protein-2 and bone morphogenetic protein-4 may play an important roles in the signaling pathways that link mechanical forces and biological responses.