Three-dimensional finite element analysis of maxillary protraction with labiolingual arches and implants.

INTRODUCTION: In this study, we aimed to evaluate the effects of maxillary protraction using traditional labiolingual arches and implant-type protraction devices before orthopedic treatment of patients with skeletal Class III malocclusion. METHODS: A 3-dimensional finite element model of the maxillofacial bones with high biologic similarity and including the sutures was constructed. Through stress and displacement calculations, a biomechanical study was performed for the maxillofacial bones, mandible, and sutures. RESULTS: We quantified detailed changes in the sutures with 2 protraction methods to analyze their effects on the growth of the maxillofacial bones. CONCLUSIONS: (1) The labiolingual arch is suitable for skeletal Class III patients with crossbite and deep overbite. The frontomaxillary and zygomaticomaxillary sutures played major roles in the forward displacement and counterclockwise rotation of the maxilla. The temporozygomatic and pterygopalatine sutures did not change significantly. (2) The implant type of protraction device is suitable for skeletal Class III patients with crossbite and open bite. Both the frontomaxillary and zygomaticomaxillary sutures played decisive roles in the forward displacement and clockwise rotation of maxilla. The temporozygomatic and pterygopalatine sutures showed small changes. (3) The labiolingual arch caused less stimulatory growth on the maxilla, whereas the implant caused greater stimulatory growth on the maxilla. Protraction with the labiolingual arch is more suitable for early skeletal Class III patients at a younger age; protraction with an implant is applicable to skeletal Class III patients in the late mixed dentition or early permanent dentition.

Osteoprotegerin deficiency results in disruption of posterofrontal suture closure in mice: implications in nonsyndromic craniosynostosis.

BACKGROUND: Little is known about the role of osteoclasts in cranial suture fusion. Osteoclasts are predominantly regulated by receptor activator of nuclear factor kappa B and receptor activator of nuclear factor kappa B ligand, both of which lead to osteoclast differentiation, activation, and survival; and osteoprotegerin, a soluble inhibitor of receptor activator of nuclear factor kappa B. The authors' work examines the role of osteoprotegerin in this process using knockout technology. METHODS: Wild-type, osteoprotegerin-heterozygous, and osteoprotegerin-knockout mice were imaged by serial micro-computed tomography at 3, 5, 7, 9, and 16 weeks. Suture density measurements and craniometric analysis were performed at these same time points. Posterofrontal sutures were harvested from mice after the week-16 time point and analyzed by means of histochemistry. RESULTS: Micro-computed tomographic analysis of the posterofrontal suture revealed reduced suture fusion in osteoprotegerin-knockout mice compared with wild-type and heterozygous littermates. Osteoprotegerin deficiency resulted in a statistically significant decrease in suture bone density in knockout mice. There was no reduction in the density of non-suture-containing calvarial bone between wild-type and osteoprotegerin-knockout mice. Histochemistry of suture sections supported these micro-computed tomographic findings. Finally, osteoprotegerin-knockout mice had reduced anteroposterior skull distance at all time points and an increased interorbital distance at the week-16 time point. CONCLUSION: The authors' data suggest that perturbations in the expression of osteoprotegerin and subsequent changes in osteoclastogenesis lead to alterations in murine cranial and posterofrontal suture morphology.

Fibrous dysplasia: management of the optic canal.

BACKGROUND: Fibrous dysplasia is an abnormal growth of bone that can lead to severe facial disfigurement. A dreaded outcome is compression of the optic nerve, leading to blindness. Controversy has surrounded the role of optic nerve unroofing for circumferential involvement of the optic canal. At present, many neurosurgeons unroof the nerve therapeutically in the setting of optic nerve dysfunction. Prophylactic unroofing (i.e., unroofing the nerve prior to the development of visual symptoms) has been previously proposed, although reported outcomes have been mixed. The authors present their long-term results of patients who have undergone optic nerve unroofing. METHODS: From 1975 to 2012, patients with fibrous dysplasia were investigated. Their age, demographics, operative procedure, optic nerve involvement (radiologically and clinically), and long-term outcomes and complications were recorded. RESULTS: Over 37 years, the senior author (S.A.W.) operated on 32 patients with fibrous dysplasia. Average follow-up was 5 years. Nine patients underwent optic nerve unroofing. Two patients had bilateral unroofing. Three patients who underwent therapeutic optic nerve unroofing ultimately went on to complete vision loss. The remaining seven patients who underwent prophylactic unroofing had no immediate postoperative visual compromise. CONCLUSIONS: Therapeutic optic nerve unroofing is advocated in fibrous dysplasia patients with continuous deterioration of vision. However, the authors believe prophylactic unroofing is safe, and it should be performed not necessarily as a primary surgical procedure, but as a procedure along with excision of fibrous dysplasia in the anterior skull base during the same operation performed for orbitocranial deformity. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

Isolated frontosphenoidal synostosis: a rare cause of synostotic frontal plagiocephaly.

OBJECT: Unilateral fusion of the frontoparietal suture is the most common cause of synostotic frontal plagiocephaly. Localized fusion of the frontosphenoidal suture is rare but can lead to a similar, but subtly distinct, phenotype. METHODS: A retrospective chart review of the authors' craniofacial database was performed. Patients with isolated frontosphenoidal synostosis on CT imaging were included. Demographic data, as well as the clinical and radiographic findings, were recorded. RESULTS: Three patients were identified. All patients were female and none had an identifiable syndrome. Head circumference was normal in each patient. The mean age at presentation was 4.8 months (range 2.0-9.8 months); 2 fusions were on the right side. Frontal flattening and recession of the supraorbital rim on the fused side were consistent physical findings. No patient had appreciable facial angulation or orbital dystopia, and 2 patients had anterior displacement of the ipsilateral ear. All 3 patients were initially misdiagnosed with unilateral coronal synostosis, and CT imaging at a mean age of 5.4 months (range 2.1-10.8 months) was required to secure the correct diagnosis. Computed tomography findings included patency of the frontoparietal suture, minor to no anterior cranial base angulation, and vertical flattening of the orbit without sphenoid wing elevation on the fused side. One patient underwent CT scanning at 2.1 months of age, which demonstrated a narrow, but patent, frontosphenoidal suture. The patient's condition was assumed to be a deformational process, and she underwent 6 months of unsuccessful helmet therapy. A repeat CT scan obtained at 10.7 months of age demonstrated the synostosis. All 3 patients underwent fronto-orbital correction at mean age of 12.1 months (range 7.8-16.1 months). The mean duration of postoperative follow-up was 11.7 months (range 1.9-23.9 months). CONCLUSIONS: Isolated frontosphenoidal synostosis should be considered in the differential diagnosis of atypical frontal plagiocephaly.

Changes in biomechanical strain and morphology of rat calvarial sutures and bone after Tgf-ß3 inhibition of posterior interfrontal suture fusion.

Craniofacial sutures are bone growth fronts that respond and adapt to biomechanical environments. Little is known of the role sutures play in regulating the skull biomechanical environment during patency and fusion conditions, especially how delayed or premature suture fusion will impact skull biomechanics. Tgf-ß3 has been shown to prevent or delay suture fusion over the short term in rat skulls, yet the long-term patency or its consequences in treated sutures is not known. It was therefore hypothesized that Tgf-ß3 had a long-term impact to prevent suture fusion and thus alter the skull biomechanics. In this study, collagen gels containing 3 ng Tgf-ß3 were surgically placed superficial to the posterior interfrontal suture (IFS) and deep to the periosteum in postnatal day 9 (P9) rats. At P9, P24, and P70, biting forces and strains over left parietal bone, posterior IFS, and sagittal suture were measured with masticatory muscles bilaterally stimulated, after which the rats were sacrificed and suture patency analyzed histologically. Results demonstrated that Tgf-ß3 treated sutures showed less fusion over time than control groups, and strain patterns in the skulls of the Tgf-ß3-treated group were different from that of the control group. Although bite force increased with age, no alterations in bite force were attributable to Tgf-ß3 treatment. These findings suggest that the continued presence of patent sutures can affect strain patterns, perhaps when higher bite forces are present as in adult animals.

Evolução clínica e tomográfica da osteomielite frontal: relato de caso / Clinical and tomography evolution of frontal osteomyelitis: case report

INTRODUÇÃO: A osteomielite frontal é uma complicação de rinossinusite que pode ter evolução aguda ou crônica. Há reação inflamatória com aumento da pressão intra-óssea, isquemia e necrose local, levando à formação de abscesso ósseo. Não havendo drenagem, ocorrerá descolamento do periósteo, invasão de partes moles e piora da isquemia com posterior sequestro ósseo. MÉTODO: Relato de caso de um paciente internado em serviço de emergência de outra instituição por complicação de rinossinusite que foi encaminhado para o Serviço de Otorrinolaringologia do Hospital Universitário Professor Edgard Santos da Universidade Federal da Bahia. RELATO DE CASO: Paciente masculino, 16 anos, apresentou-se ao serviço de emergência de outra instituição com cefaleia, vômitos e febre que evoluiu com edema periorbitário e frontal à esquerda, cursando com flutuação palpebral e frontal.Submetido à drenagem de abscesso palpebral e frontal, com antibioticoterapia de amplo espectro sem melhora. Encaminhado para o nosso serviço mantendo edema e flutuação em região frontal e edema leve em região periorbitária esquerda. A endoscopia nasal evidenciou edema em meato médio à esquerda e a tomografia computadorizada mostrou sinusite fronto-etmoidal à esquerda e sinais de osteomielite frontal com sequestro ósseo e empiema epidural.Submetido à cirurgia endoscópica nasossinusal, acesso externo para exérese do osso frontal acometido e drenagem do empiema epidural. Evoluiu com remissão da doença. CONSIDERAÇÕES FINAIS: A falência no diagnóstico e no tratamento das complicações da rinossinusite pode levar a sequelas e complicações fatais.O diagnóstico de osteomielite frontal é firmado pela suspeita clinica e confirmado por exames radiológicos.A cirurgia está indicada quando a evolução for insidiosa, havendo sequestro ósseo ou complicações intracranianas.

INTRODUCTION: The frontal osteomyelitis is a complication of rhinosinusitis which can evolve to acute or chronicle. There is inflammatory reaction by the increasing of intraosseous pressure, ischemia and local necrosis, leading to bone abscess formation. There is no drainage, it will occur detachment of the periosteum, soft tissue invasion and worsening of ischemia with subsequent bone sequestration. METHOD: Case report of an inpatient in an emergency service of another institution by the complication of rhinosinusitis who was referred to the Otorhinolaryngology Service of University Hospital Professor Edgard Santos of Federal University of Bahia. CASE REPORT: Male patient, 16 years-old, presented himself to the ER of another institution with cephalea, vomits and fever which evolved to periorbital edema and frontal to the left, moving to palpebral fluctuation and frontal. Subjected to frontal and palpebral abscess drainage, with broad-spectrum antibiotic therapy with no improvement. He was referred to our service keeping edema and fluctuation in region frontal and light edema in left periorbital region. The nasal endoscopy showed edema in meatus to the left and the computerized tomography showed fronto-ethmoid sinusitis to the left and signs of frontal osteomyelitis with bone sequestration and epidural empyema. Subjected to sinasal endoscopy surgery, external Access or removal of the frontal one affected and epidural empyema drainage. Evolved to the remission of the disease. FINAL CONSIDERATIONS: Failure in the diagnosis and rhinosinusitis complication treatment can lead to sequalae and fatal complications. The diagnosis of the frontal osteomyelitis is confirmed by the clinical suspicion and confirmed by radiological examination. The surgery is indicated when the evolution is insidious, there is bone sequestration and intracranial complications.

Diabetes mellitus negatively affects peri-implant bone formation in the diabetic domestic pig.

AIM: Diabetes mellitus is classified as a relative contraindication for implant treatment, and higher failure rates have been seen in diabetic patients. The aim of the present study was to investigate the effect of diabetes on peri-implant bone formation in an animal model of human bone repair. MATERIALS AND METHODS: Diabetes was induced by an intra-venous application of streptozotocin (90 mg/kg) in 15 domestic pigs. Implants were placed after significant histopathological changes in the hard and soft tissues were verified. The bone-implant contact (BIC), peri-implant bone mineral density (BMD), and expression of collagen type-I and osteocalcin proteins were qualitatively evaluated 4 and 12 weeks after implantation. Fifteen animals served as healthy controls. RESULTS: Diabetes caused pathological changes in the soft and hard tissues. The BIC and BMD were significantly reduced in the diabetic group after 4 and 12 weeks. Collagen type-I was increased in the diabetic group at both time points, whereas osteocalcin was reduced in the diabetic group. CONCLUSIONS: Poorly controlled diabetes negatively affects peri-implant bone formation and bone mineralization. These findings have to be taken into consideration for diabetic patients with an indication for implant therapy.

Continuous forces are more effective than intermittent forces in expanding sutures.

SUMMARY: While both intermittent and continuous forces are commonly used to expand sutures, it remains unclear which force is most effective. Using nickel-titanium (NiTi) open coil springs (50 g) and 3 mm long miniscrew implants (MSIs) for skeletal anchorage, intermittent and continuous forces were used to expand the midsagittal sutures in 18 New Zealand white juvenile male rabbits, 11 weeks of age, for 29 days. In the intermittent group, expansion forces of 50 g were delivered for 5 days (on) and paused for 1 day (off); the on/off cycles were repeated five times. Expansion forces of 50 g were delivered for 29 consecutive days in the continuous group. Longitudinal biometric and histomorphometric analyses were performed to evaluate sutural separation and bone formation using implanted tantalum bone markers and fluorescent bone labelling, respectively. Multilevel modelling procedures were undertaken to compare the groups and time intervals. Continuous forces produced significantly greater overall sutural separation (1.3 mm) than intermittent forces (0.8 mm). Although they were delivered over a period of time 86 per cent as long, intermittent forces produced only 61 per cent of the sutural separation of continuous forces. Between days 7 and 17, continuous forces resulted in significantly greater mineral apposition and bone formation rates than intermittent forces. Intermittent forces produced approximately 59 per cent as much mineral apposition and 61 per cent as much bone formation as continuous forces. Due to greater sutural separation and bone formation, continuous forces provide a more effective approach for separating sutures than intermittent forces.

Maxillary protraction with and without maxillary expansion: a finite element analysis of sutural stresses.

INTRODUCTION: In this finite element study, we compared the stress patterns along the various craniofacial sutures with maxillary protraction with and without expansion. METHODS: Two 3-dimensional analytic models were developed, 1 simulating maxillary protraction and the other simulating maxillary protraction with expansion. The model consisted of 108799 10 node solid 92 elements (tetrahedron), 193633 nodes, and 580899 degrees of freedom. RESULTS: The overall stresses after maxillary protraction with maxillary expansion were significantly higher than with a facemask alone. The magnitude of stress on the craniofacial sutures with maxillary protraction alone was in the range of a few millinewtons per square millimeter, whereas, with maxillary protraction with maxillary expansion, the stresses ranged from a few newtons per square millimeter to a few hundred newtons per square millimeter. The pattern of stress distribution also differed with the 2 treatment modalities as did the sutures experiencing maximum and minimum stresses. CONCLUSIONS: The osteogenic potential of such low stresses after maxillary protraction can be questioned. High stresses generated in various craniofacial sutures after maxillary protraction with expansion are responsible for disrupting the circummaxillary sutural system and presumably facilitating the orthopedic effect of the facemask.

Tumor de Pott / Pott´s Puffy tumor

Tumor de Pott (Pott‘s Puffy tumor) é uma comorbidade caracterizada por um ou mais abscessos sub-periosteais do osso frontal associados a osteomielite subjacente. As etiologias incluem trauma e sinusite, entre outras. Relatamos o caso de uma paciente de 17 anos que se apresentou com abaulameto doloroso, calor local e flutuação na região frontal à direita há um mês, bem como cefaléia holocraniana e hipertermia. O diagnóstico de Tumor de Pott como uma complicação de uma sinusite frontal foi estabelecido pela clínica e confirmado por tomografia computadorizada de crânio. Foi tratada com sucesso com esquema inicial de amoxicilina mais clavulanato, o qual foi substituído por ciprofloxacina, associados à craniotomia, com craniectomia do osso acometido. Esta é uma doença que por ser infreqüente muitas vezes não é diagnosticada. Deste modo enfatizamos o diagnóstico e tratamento precoces como forma de evitar seqüelas neurológicas.

Pott‘s Puffy Tumor is a comorbidity characterized by one or multiple subperiosteal abscesses of the frontal bone associated with underlying osteomyelitis. Etiologies include trauma and sinusitis among others. Here we report the case of a 17-year-old female patient with painful bulging, local heat, and fluctuation in the frontal region on the right for a month, as well as holocranial headache and hyperthermia. The diagnosis of Pott‘s Puffy Tumor as a complication of frontal sinusitis was clinically established and confirmed by computerized tomography of the skull. It was successfully initially treated with amoxicilin + clavunate, followed by ciprofloxacin, combined with craniotomy and craniectomy of the affected bone. Because of its rarity, this disorder often goes underdiagnosed. Thus we emphasize an early diagnosis and treatment so as to avoid neurological sequels.

Influence of cranial morphology on the location of chronic subdural haematoma.

BACKGROUND: The purpose of the present study was to evaluate the relationship between cranial morphology and location of a chronic subdural haematoma (CSDH) in patients with and without intracranial vault asymmetry. METHOD: The study was conducted in 110 consecutive adult patients who underwent surgery for CSDH. The relationship between the following variables and CSDH was studied: sex, age, past medical history, history of trauma, interval between head injury and symptoms, clinical presentation, location of the CSDH, symmetry of the frontal and occipital intracranial vault on the CT scan and/or MR images, surgical treatment and outcome. Throughout the analysis, p < 0.05 was considered statistically significant. FINDINGS: The frontal cranial vault was symmetrical in 48 patients (43.6%) and asymmetrical in 62 patients (56.4%). CSDH was more commonly bilateral in patients with a symmetrical frontal cranial vault than those with an asymmetrical shape (41.7% vs 17.7% and this difference is statistically significant (p = 0.01). In 62 patients with an asymmetric frontal skull vault, the CSDH was bilateral in 11 patients. In the remaining 51 patients, the CSDH was located on the same side of the most curved frontal convexity in 34 patients and on the side of the less curved frontal convexity in 17 patients. The occipital cranial vault was symmetrical in 44 patients (40%) and asymmetrical in 66 patients (60%). CSDH was more commonly bilateral in patients with a symmetrical occipital cranial vault than those with an asymmetrical one (40.9% vs 19.7%) and this difference was also statistically significant (p = 0.019). In 66 patients with an asymmetric occipital skull vault, the CSDH was bilateral in 13 patients. In the remaining 53 patients, the CSDH located on the same side of the most curved occipital convexity in 39 patients and on the side of the less curved occipital convexity in 14 patients. CONCLUSIONS: Frontal and occipital intracranial vault morphology provides valuable information about location of CSDH. Bilateral CSDH is common in patients with symmetrical frontal and occipital cranial vault. In asymmetrical cranium, CSDH usually locates on the same side of the most curved frontal or occipital convexity. Identification of this relationship can be very useful to elucidate the origin and the pathogenesis of CSDH.

The evaluation of bony union after frontofacial distraction.

Frontofacial advancement by distraction osteogenesis using the rigid external distraction device has become an accepted treatment for the deformity associated with craniofacial dysostoses (e.g., Crouzon, Apert, and Pfeiffer syndromes). The technical and physiological principles of osteogenesis distraction are well understood. This study documents the pattern of calcification at the osteotomy sites after distraction by analysis of serial three-dimensional computed tomography (CT) scans. The CT scans of 25 patients (11 with Crouzon, 6 with Apert, and 8 with Pfeiffer syndrome) were analyzed. Eleven individual areas along the osteotomy lines were assessed for evidence of bone formation. Scores were assigned within 4 categories ranging from no bone, calcification without bridge formation, a bony bridge, to complete bony infill (>95%). The scans were reviewed on 2 separate occasions by 2 independent assessors. There was high concordance both for intraobserver and interobserver scores. Rigid external distraction frame removal was undertaken after a 6-week consolidation period. All CT scan timings were calculated from this date. Of the 25 patients studied, 16 patients had CT scans available at 3 to 6 months, 12 at 9 to 12 months, and 7 at or more than 18 months. The scans were available in standard coronal slices with three-dimensional reconstructions. Bone formation is most consistently seen in the pterygoid region with calcification consistently occurring earlier and more completely in this area. Bone formation was often delayed in the orbital region and severely delayed or absent in the frontal region and zygomatic arches. There was no significant difference in the order or quality of bony union for the 3 underlying craniofacial dysostoses. This preliminary study confirms the clinical impression that bone formation after distraction is greatest in the pterygoid regions. The clinical implications of these findings are discussed.

Fluctuating asymmetry and developmental instability in sagittal craniosynostosis.

OBJECTIVE: To determine whether premature sagittal craniosynostosis is associated with developmental instability in the skull by analyzing fluctuating asymmetry in skull shape. DESIGN: Cranial shape was quantified by collecting coordinate data from landmarks located on three-dimensional reconstructions of preoperative computed tomography (CT) images of 22 children with sagittal craniosynostosis and 22 age-matched controls. A fluctuating asymmetry application of Euclidean distance matrix analysis (EDMA) was used to quantify and compare asymmetry in cranial shape using these landmark data. RESULTS: In contrast to expectations, the sagittal craniosynostosis group did not show a statistically significant increase in the overall level of fluctuating asymmetry relative to the control group. However, we discerned statistically significant localized increases in fluctuating asymmetry in the sagittal craniosynostosis group at pterion and the anterior clinoid processes (alpha = .05). We also determined a significant correlation of fluctuating asymmetry values between the two groups (r = .71). CONCLUSIONS: We conclude that there is no evidence of a role for system-wide developmental instability in the etiology of nonsyndromic sagittal craniosynostosis. However, the localized evidence of asymmetry at the anterior clinoid processes in the sagittal synostosis group suggests an association with the tracts of dura mater that attach there.

Sutural strain in orthopedic headgear therapy: a finite element analysis.

INTRODUCTION: The goal of this study was to analyze the strains induced in the sutures of the midface and the cranial base by headgear therapy involving orthopedic forces. Does the mechanical signal induced in the sutures sufficiently account for a growth-influencing effect? METHODS: A finite element model of the viscerocranium and the neurocranium was used. It consisted of 53,555 tetrahedral elements and 97,550 nodes. The strain induced in the sutures of the cranial base and the midface when applying orthopedic headgear forces of 5 and 10 N was computed and recorded with an interactive measurement tool. RESULTS: The magnitude and the distribution of the measured strains depended on the level and the direction of the acting force. Overall, the strain values measured at the sutures of the midface and the cranial base were moderate. The measured peak values at a load of 5 N per side were usually just below 20 microstrain irrespective of the force direction. A characteristic distribution of strain values appeared on the anatomical structures of the midface and the cranial base for each vector direction. The measurements based on the finite element method provided a good overview of the approximate magnitudes of sutural strains with orthopedic headgear therapy. The signal arriving in the sutures is apparently well below threshold, since the maximum measured strains in most sutures were about 100 fold lower than the minimal effective strain. A skeletal effect of the orthopedic headgear due to a mechanical effect on sutural growth cannot be confirmed from these results. CONCLUSIONS: The good clinical efficacy of headgear therapy with orthopedic forces is apparently based mainly on dentoalveolar effects, whereas the skeletal effect due to inhibition of sutural growth is somewhat questionable.

Biomechanics of frontal skull fracture.

The purpose of the present study was to investigate whether an energy failure level applies to the skull fracture mechanics in unembalmed post-mortem human heads under dynamic frontal loading conditions. A double-pendulum model was used to conduct frontal impact tests on specimens from 18 unembalmed post-mortem human subjects. The specimens were isolated at the occipital condyle level, and pre-test computed tomography images were obtained. The specimens were rigidly attached to an aluminum pendulum in an upside down position and obtained a single degree of freedom, allowing motion in the plane of impact. A steel pendulum delivered the impact and was fitted with a flat-surfaced, cylindrical aluminum impactor, which distributed the load to a force sensor. The relative displacement between the two pendulums was used as a measure for the deformation of the specimen in the plane of impact. Three impact velocity conditions were created: low (3.60+/-0.23 m/sec), intermediate (5.21+/-0.04 m/sec), and high (6.95+/-0.04 m/sec) velocity. Computed tomography and dissection techniques were used to detect pathology. If no fracture was detected, repeated tests on the same specimen were performed with higher impact energy until fracture occurred. Peak force, displacement and energy variables were used to describe the biomechanics. Our data suggests the existence of an energy failure level in the range of 22-24 J for dynamic frontal loading of an intact unembalmed head, allowed to move with one degree of freedom. Further experiments, however, are necessary to confirm that this is a definitive energy criterion for skull fracture following impact.

The effect of platelet-rich plasma on early and late bone healing: an experimental study in goats.

Four round critical-size defects were made in the foreheads of 20 goats. The defects were filled with autogenous particulate cancellous bone, in which 1 ml of platelet-rich plasma (PRP) was added in two of the four defects of each goat. The goats were divided into four subgroups of five goats each, which were killed after 1, 2, 6 and 12 weeks. The results of histologic and histomorphometric examination showed that early and late bone healing was not enhanced when PRP was used.

Delayed development of frontal mucocele after fronto-orbital advancement in a child with craniosynostosis.

BACKGROUND: Sinus mucoceles rarely develop as a consequence of inadequate sinus ventilation that arises due to inflammation, allergy, polyps, tumors, surgery, and trauma. The development of frontal sinus is delayed until older than 6 years. Therefore, the development of the mucocele in the frontal sinus after fronto-orbital advancement surgery in young children with craniosynostosis may provide essential information for the development of the frontal sinus. CASE DESCRIPTION: We report a rare case of a 22-year-old man presenting with a frontal mucocele manifested by dull headache, proptosis, and diplopia, and which developed 16 years after fronto-orbital advancement surgery for craniosynostosis. Magnetic resonance imaging demonstrated that a multiple cystic mass extended from the frontal sinus to the retro-orbital space along the optic nerve. During surgery, we found that the cyst consisted of mostly thin, yellow mucosa, which developed from an anomalously overdeveloped frontal sinus containing yellow pus-like intracystic fluid. There was no gross local invasion by the cyst. We easily dissected and removed the mucosal cyst from the large frontal sinus completely with frontal sinus obliteration. We cranialized the anomalously large frontal sinus by removal of the posterior wall of the frontal sinus and then widening the ethmoidal drainage with endoscopic ethmoidectomy. CONCLUSION: We report the first case of a frontal sinus mucocele that developed after fronto-orbital advancement surgery in the literature and suggest that the mucocele development after fronto-orbital advancement supports the hypothesis of frontal bone-inducing role in frontal sinus development.

Biomechanical effects of rapid palatal expansion on the craniofacial skeleton with cleft palate: a three-dimensional finite element analysis.

OBJECTIVE: To explore the biomechanical effects of rapid palatal expansion (RPE) on the craniofacial skeleton with cleft palate. DESIGN: A finite element model of a patient's skull with cleft lip and palate (CLP) was generated using data from spiral computed tomographic (CT) scans. Finite elemental analysis (FEA) was performed to depict the physiological changes and stress distribution in craniofacial structures loaded with orthopedic forces that created 5 mm of displacement on the region of the maxillary first premolar and first molar crown. PATIENTS, PARTICIPANTS: A 14-year-old girl with left complete unilateral CLP was included in this study. INTERVENTIONS: Spiral CT was carried out prior to any treatment. MAIN OUTCOME MEASURE(S): Three-dimensional (3D) features of displacement and stress distribution were analyzed following application of transverse orthopedic force. RESULTS: Marked amount of displacement and deformation occurred in the dental region. Asymmetric displacement and deformation of UCLP under RPE were evident. The stress generated by RPE was dispersed around the cleft palate and nasal cavity, and was distributed at the buttress of the maxilla-inferior border of the nasal cavity, outboard of the orbit, and central frontal bone near the nasion. CONCLUSIONS: Application of RPE to UCLP patients induces a pyramid-like displacement of the nasomaxillary complex along with fan-like expansion of the upper dental arch. The uniqueness of RPE with UCLP, however, lies in the asymmetric expansion and dispersed stress distribution around the lateral maxilla buttress and outboard of orbit.

Nanostructural and nanomechanical properties of synostosed postnatal human cranial sutures.

Craniosynostosis represents a heterogeneous cluster of congenital disorders and manifests as premature ossification of one or more cranial sutures. Cranial sutures serve to enable calvarial growth and function as joints between skull bones. The mechanical properties of synostosed cranial sutures are of vital importance to their function and yet are poorly understood. The present study was designed to characterize the nanostructural and nanomechanical properties of synostosed postnatal sagittal and metopic sutures. Synostosed postnatal sagittal sutures (n = 5) and metopic sutures (n = 5) were obtained from craniosynostosis patients (aged 9.1 +/- 2.8 months). The synostosed sutural samples were prepared for imaging and indentation on both the endocranial and ectocranial surfaces with the cantilever probe of an atomic force microscopy. Analysis of the nanotopographic images indicated robust variations in sutural surface characteristics with localized peaks and valleys. In 5 x 5 mum scan sizes, the surface roughness of the synostosed metopic suture was significantly greater (223.6 +/- 93.3 nm) than the synostosed sagittal suture (142.9 +/- 80.3 nm) (P < 0.01). The Young's modulus of the synostosed sagittal suture at 0.7 +/- 0.2 MPa was significantly higher than the synostosed metopic suture at 0.5 +/- 0.1 MPa (P < 0.01). These data suggest that various synostosed cranial sutures may have different structural and mechanical characteristics.