Distinctive Capillary Action by Micro-channels in Bone-like Templates can Enhance Recruitment of Cells for Restoration of Large Bony Defect

Without an active, thriving cell population that is well-distributed and stably anchored to the inserted template, exceptional bone regeneration does not occur. With conventional templates, the absence of internal micro-channels results in the lack of cell infiltration, distribution, and inhabitance deep inside the templates. Hence, a highly porous and uniformly interconnected trabecular-bone-like template with micro-channels (biogenic microenvironment template; BMT) has been developed to address these obstacles. The novel BMT was created by innovative concepts (capillary action) and fabricated with a sponge-template coating technique. The BMT consists of several structural components: inter-connected primary-pores (300-400 µm) that mimic pores in trabecular bone, micro-channels (25-70 µm) within each trabecula, and nanopores (100-400 nm) on the surface to allow cells to anchor. Moreover, the BMT has been documented by mechanical test study to have similar mechanical strength properties to those of human trabecular bone (~3.8 MPa)¹².

The BMT exhibited high absorption, retention, and habitation of cells throughout the bridge-shaped (Π) templates (3 cm height and 4 cm length). The cells that were initially seeded into one end of the templates immediately mobilized to the other end (10 cm distance) by capillary action of the BMT on the cell media. After 4 hr, the cells homogenously occupied the entire BMT and exhibited normal cellular behavior. The capillary action accounted for the infiltration of the cells suspended in the media and the distribution (active migration) throughout the BMT. Having observed these capabilities of the BMT, we project that BMTs will absorb bone marrow cells, growth factors, and nutrients from the periphery under physiological conditions.

The BMT may resolve current limitations via rapid infiltration, homogenous distribution and inhabitance of cells in large, volumetric templates to repair massive skeletal defects.

Resection of an upper cervical aneurysmal bone cyst and spinal reconstruction using a midline mandibular osteotomy in a pediatric patient

The authors report on the surgical management of an extensive lesion of the upper cervical spine that required an uncommon transmandibular approach to facilitate exposure, resection, and stabilization in a pediatric patient. A 6-year-old boy with a large aneurysmal bone cyst of the C-2 vertebra presented with progressive weakness and right-sided neck pain. The lesion extended laterally into the soft tissue of the neck, inferiorly to C-4, and posteriorly around the spinal cord. A transmandibular osteotomy was performed to provide adequate exposure for complete resection of the mass and anterior C1-3 instrumentation and fusion. Subsequently, the patient underwent occiput to C-4 posterior instrumentation and fusion. The patient tolerated the operation well and had regained all function at 3 and 11 months' follow-up. No neurological complications or problems of speech, swallowing, or respiration occurred. Even in pediatric patients, the transmandibular approach for the treatment of upper cervical spine lesions is an effective method of maximizing exposure for complex lesions requiring resection and stabilization.

Solitary orbital myofibroma: clinical, radiographic, and histopathologic findings. A report of two cases

This describes a non-interventional case series of 2 patients, aged 7 and 9 years referred to Oculoplastic Unit, both for evaluation of a gradually enlarging, painless, mass of the cheek. CT scan of the first case revealed left orbital floor destruction from a well-defined intraosseous mass. The second was a round circumscribed orbital floor tumor without bone destruction. Histological diagnosis of myofibroma was rendered in both cases. Solitary myofibromas are rare in the orbit. Their rapid growth and bony destruction can mimic malignant tumors. Complete excision with close follow-up is the preferred treatment. Solitary myofibroma should be considered in the differential diagnoses of fibrous tumors with bone destruction in the orbit.

Alternative indications for bisphosphonate therapy

Bisphosphonates are currently used in the treatment of osteoporosis (postmenopausal and steroid-induced), hypercalcemia of malignancy, Paget's disease of bone, multiple myeloma, and skeletally related events associated with metastatic bone disease in breast, prostate, lung, and other cancers. There are, however, numerous other conditions where a decrease in bone remodeling by bisphosphonates might aid in disease management. The focus of this review will be to discuss a select group of conditions for which bisphosphonate therapy may be efficacious. In this review we present several cases where bisphosphonates have been used as a primary or adjunctive treatment for giant cell lesions of the jaws. Use of bisphosphonate therapy for giant cell tumors of the appendicular skeleton, pediatric osteogenesis imperfecta, fibrous dysplasia, Gaucher's disease, and osteomyelitis will be discussed. Finally, we will review previous in vivo studies on the use of bisphosphonates to augment integration and to treat osteolysis surrounding failing orthopedic implants.

Controlled delivery of platelet-rich plasma-derived growth factors for bone formation

Platelet-rich plasma (PRP) represents an autologous source of growth factors essential for bone regeneration. The clinical efficacy of PRP is, however, unpredictable, and this is likely due to the inefficient and inconsistent delivery of PRP-derived growth factors. Previous investigations have shown that current methods of PRP preparation result in a premature release of the relevant bone stimulatory factors. As successful bone regeneration requires multiple factors presented in a physiologic temporal and spatial cascade, the objective of this study is to control the bioavailability of PRP-derived growth factors using a hydrogel carrier system. Specifically, the release of platelet-derived growth factor, transforming growth factor beta-1, and insulin-like growth factor from two types of alginate carriers was compared over time. The effects of the released factors on the growth and alkaline phosphatase (ALP) activity of human osteoblast-like cells were also evaluated. It was found that factor release profiles varied as function of carrier type, and binding of growth factors to the alginate matrix also modulated their release. The bioactivity of released factors was maintained in vitro and they promoted cell proliferation and ALP activity. These results demonstrate the potential of this autologous multifactor delivery system for controlling the bioavailability of PRP-derived factors. Future studies will focus on optimizing this system to increase the clinical efficacy of PRP by matching the distribution and temporal sequencing of PRP-derived factors to the bone healing cascade.

Cherubism: clinicopathologic features

A case of cherubism in 6-year-old boy is reported. He presented with bilateral symmetrical enlargement of the jaw in addition to medially dislocated premature teeth, narrow V-shaped palatal vault, and mild upward turning of the eyes. Radiographs showed multiloculated osteolysis in both the mandible and maxilla. Histology revealed a non-neoplastic fibrous lesion, rich in multinucleated giant cells, consistent with giant-cell reparative granuloma. Since the original description of cherubism, various histologic interpretations have been proposed, particularly that of fibrous dysplasia. However, it should be emphasized that cherubism is a disease histologically indistinguishable from giant-cell reparative granuloma.

Surgical prediction reliability: a comparison of two computer software systems

The purpose of this study was to test and compare the accuracy and reliability of soft tissue profile predictions generated from two computer software programs. The presurgical and postsurgical cephalometric radiographs of 28 patients were digitized onto each computer program. A customized analysis was created to determine the amount of surgical movement, as well as to compare the actual postsurgical soft tissue profile with the computer-generated prediction. The results demonstrated that, on the average, the predictions were not significantly different from the actual postsurgical profile changes. While each program generated statistically similar prediction results, marked variability was noted. There was no significant difference found in the prediction errors between patients who had one-jaw surgery and those who had two-jaw surgery. This study found that a linear relationship existed between the surgical movement and the prediction error. In general, the greater the magnitude of the surgical movement, the larger the prediction error.

Effect of supplemental gases on end-tidal CO2 and oxygen saturation in patients undergoing fentanyl and midazolam outpatient sedation

Forty-six American Society of Anesthesiologists Class I and II adults were randomly assigned to one to two study groups. Each subject received 0.7 microgram/kg of fentanyl and a titrated dose of midazolam. One group received 100% supplemental oxygen (O2) while another group received 50% nitrous oxide (N2O) and 50% O2. End-tidal carbon dioxide (EtCO2) and O2 saturation (SpO2) were measured at 5-min intervals throughout the procedure. We conclude that there was no significant difference in EtCO2 or O2 saturation between the two groups.

Comparison of recovery of propofol and methohexital sedation using an infusion pump

Two sedative anesthetic agents administered by an infusion pump were compared during third molar surgery. Forty American Society of Anesthesiologists (ASA) class I or II volunteers were randomly allocated to two groups. All subjects received supplemental oxygen via a nasal hood, fentanyl (0.0007 mg/kg intravenous [i.v.] bolus), and midazolam (1 mg/2 min) titrated to effect. Patients then received either 0.3 mg/kg of methohexital or 0.5 mg/kg of propofol via an infusion pump. Upon completion of the bolus, a continuous infusion of 0.05 mg/kg/min methohexital or 0.066 mg/kg/min propofol was administered throughout the procedure. Hemo-dynamic and respiratory parameters and psychomotor performance were compared for the two groups and no significant differences were found. The continuous infusion method maintained a steady level of sedation. Patients receiving propofol had a smoother sedation as judged by the surgeon and anesthetist.

Effects of rigid fixation device composition on three-dimensional computed axial tomography imaging: direct measurements on a pig model

OBJECTIVE

To compare the amount of scatter produced by titanium plates versus Vitallium (Howmedica, Rutherford, NJ) plates. Software was also evaluated to determine its effectiveness in removing the scatter and clarifying the underlying anatomy.

MATERIALS AND METHODS

Miniplating and microplating systems composed of Vitallium or titanium were placed on the nasal and frontal bones of three adult pig heads. A computerized axial tomography (CAT) scan was then performed and a three-dimensional CAT scan was reconstructed using MediCad software (MediCad Inc, Cedar Knolls, NJ). The amount of scatter for each plating system was quantitated using the MediCad software measuring tool. The scatter was removed and the three-dimensional CAT scan was reconstructed to assess the clarification of the underlying anatomy.

RESULTS

No scatter was found with either the miniplating or the microplating system composed of titanium. The Vitallium plates did show significant amount of scatter with the mini, micro, and micromesh system. Removal of the scatter resulted in slight improvement in the anatomic detail.

CONCLUSION

Titanium plating systems do not cause any radiation scatter. The MediCad software system allows removal of the scatter found with the Vitallium plates, which helps clarify the underlying anatomy.

Achondroplasia: pre- and postsurgical considerations for midface advancement

Achondroplasia, the most common type of dwarfism, involves several physical characteristics that can cause pre- and intraoperative respiratory problems. The characteristics include rib-cage deformities, midface hypoplasia, choanal stenosis, muscular hypotonia, foramen magnum compression, and cervical abnormalities. Specific pre- and postoperative strategies for dealing with achondroplastic dwarfs are discussed.

Pigmented villonodular synovitis of the temporomandibular joint. Case report and review of the literature

A case of pigmented villonodular synovitis of the right temporomandibular joint with extension through the base of the skull into the middle cranial fossa is described. The patient initially had right-sided hearing loss. Physical examination revealed a mass in the right ear canal. Computerized axial tomography demonstrated a destructive lesion of the right temporomandibular joint, with extension into the middle cranial fossa. The surgical approach is discussed, and the 11 previously reported cases are reviewed.

Major aphthous-like ulcers in patients with AIDS

This report describes persistent, painful oral ulcers that occurred in nine patients with the acquired immunodeficiency syndrome (AIDS). These ulcers resembled major aphthous ulcers in clinical appearance and response to therapy. They occurred less frequently in patients with AIDS than those caused by herpes simplex and were found in 4 of 346 (1.1%) patients with AIDS at one medical center. Lesions were typically painful. Identification and treatment with topical tetracycline and steroids led to resolution with relief of symptoms. Further study is necessary to understand the etiology and pathogenesis of these ulcers.

Maxillary ameloblastoma: report of an unusual case

The ameloblastoma is an unusual neoplasm in the pediatric population. A maxillary ameloblastoma was discovered during evaluation for premolar extractions. Treatment and the importance of obtaining a histological evaluation are discussed.

False aneurysm of the facial artery

A case of an unusual traumatic aneurysm of the facial artery secondary to blunt trauma is reported. The lesion was typical in that it was pulsatile, had a systolic bruit, and had a filling defect that was evident on carotid angiography. Although a traumatic aneurysm is a rare occurrence in the facial region, the inclusion of this lesion in the differential diagnosis of soft tissue lesions is important if the serious consequences of hemorrhage are to be avoided.

Unilateral craniofacial microsomia. Part I. Mandibular analysis

Various attempts to describe the skeletal characteristics of unilateral craniofacial microsomia have been made with the use of cephalometric and panoramic roentgenograms. Previous studies have been only descriptive in nature. To date, a detailed (quantitative) cephalometric analysis of the mandibular deformity has not been reported. The purpose of this study was to describe the skeletal jaw deformity by means of cephalometric landmarks in the lateral view. The patient population consisted of sixteen boys and eight girls who ranged in age from 6 to 16 years. They were compared to the University of Michigan normal control population for the following measures: gonial angle, mandibular plane angle, overall oblique length of the mandible, ramal height, and body length. The affected side showed a larger gonial angle and mandibular plane angle. The oblique length of the mandible (Cd-Gn) was decreased on both sides, as were ramal height and body length. Paradoxically, body length appeared shorter on the unaffected side than on the affected side. This paradoxical observation could be attributed to a shift of the mandible in relation to the midsagittal plane of the cranial base, the film cassette, and the path of the x-ray beam. Observation of the mandible in the basilar cephalogram explained the geometry of the projection error found in the lateral view. Similar projection errors exist for patients with other types of craniofacial asymmetry. It is suggested that two radiographic views, orthogonal to each other, should be used to define the x, y, and z planes for studies of craniofacial abnormality.