Derek M. Steinbacher

Expansion of the posterior cranial vault using distraction osteogenesis.

Background: Expansion of the posterior cranial vault more profoundly enlarges intracranial volume compared with the anterior region.1 Conventional vault remodeling techniques are limited by scalp forces and may relapse with supine positioning. The purpose of this study was to demonstrate the efficacy of posterior vault distraction and evaluate perioperative variables compared with conventional methods in syndromic children. Methods: This was a retrospective analysis of consecutive children who underwent posterior vault expansion using distraction osteogenesis. Information was compiled regarding demographics, perioperative details, distraction protocol, and complications. Results: Eight children were identified, two boys and six girls. Diagnoses of Apert, Crouzon, Saethre-Chotzen, and Pfeiffer syndromes were present. Chiari malformation was present in two children. The posterior distraction procedure was undertaken at a mean of 21 months (range, 5 to 36 months). Mean operative time was 3.8 hours (range, 2.6 to 5 hours), blood loss averaged 487 ml (range, 300 to 2000 ml), and hospital stay was 3.25 days (range, 2 to 4 days). A latency period of 72 hours and rate of 2/3 mm/day was used in three patients, and 1 mm/day was used in five children. The mean advancement was 23 mm (range, 19 to 32 mm) and consolidation was 77 days (range, 42 to 100 days). One child experienced fracture of distraction arms during the activation period. Mean follow-up was 278 days (range, 90 to 548 days). Conclusions: These preliminary findings indicate that posterior vault distraction is a viable technique with a favorable perioperative profile compared with conventional treatment. Posterior distraction can be the initial strategy with which to address intracranial pressure, allowing delay of definitive frontoorbital advancement until later in childhood.

The effect of age on human adipose-derived stem cells.

Background: Adipose-derived mesenchymal stem cells are a robust, multipotent cell source. They are easily harvested and exhibit promise in a variety of regenerative applications. The purpose of this study was to evaluate the aging impact on adipose-derived mesenchymal stem cells, relating to morphology, senescent properties, growth factor expression, and osteogenesis. Methods: Cells obtained from distinct age groups (infant, adult, and elderly) were cultured. Morphology was examined using microscopy, and cell surface markers were interrogated using flow cytometry. Telomere length was measured using real-time polymerase chain reaction. Expression of pertinent angiogenic and osteogenic growth factors was compared. Osteogenic capability was investigated further by evaluating induction response, and by quantification of mRNA expression of RUNX-2 and osteocalcin. Results: The same isolating ratio of mesenchymal stem cells was derived from each donor, regardless of age. The infant adipose-derived stem cells exhibited elongated spindle morphology and increased telomere length compared with older cells. Angiogenic factors were more highly expressed by infant cells, whereas osteogenic expression was similar among all ages. Response to osteogenic induction was more profound in infant than in older stem cells, as evidenced by alkaline phosphatase and alizarin red staining, as was bone-related gene expression. Conclusions: Adipose-derived mesenchymal stem cells are available across all age groups. Infant-derived cells are morphologically spindle-shaped, with long telomeres, and exhibit enhanced angiogenic and osteogenic capabilities compared with older cells. Conversely, all age groups exhibit similar osteogenic paracrine activity, and the authors posit that clinical applicability is conserved during the adult to elderly period.

Three-Dimensional Virtual Surgery Accuracy for Free Fibula Mandibular Reconstruction: Planned Versus Actual Results

PURPOSE Virtual surgical planning (VSP) can promote efficiency, but the ability to transfer the proposed plan to the actual result has not been adequately studied. The purpose of this study was to morphometrically compare the virtually preplanned scenario with the postoperative 3-dimensional (3D) anatomic result. MATERIALS AND METHODS A retrospective review of 10 patients who underwent mandibular reconstruction using a free fibula flap and VSP were evaluated. Pre- and postoperative Digital Imaging and Communications in Medicine files were imported into Mimics 10.01 software (Materialise, Leuven, Belgium) for surgical planning. Preoperative VSP and 1-week postoperative computed tomographic (CT) scans were evaluated to assess surgical accuracy using VSP. The pre- and postoperative morphometric measurements were compared using the Student t test. RESULTS Twenty CT scans from 10 patients (mean age, 56.9±20.2 yr) who underwent partial mandibular resection were analyzed. The dimensions of the fibula segments after osteotomy showed no difference from the preoperative VSP (mean difference in fibula height, 1.2 mm; mean difference in width, 0.9 mm; mean difference in length, 1.3 mm). The postoperative anterior and posterior mandibular angles differed from the VSP by 12.4° and -12.5°, respectively. The condylar distance and inclination showed a discrepancy of only 1.7 mm and 4.6°, respectively, between VSP and postoperative CT scans. CONCLUSIONS VSP confers reproducible precision and accuracy for free fibular mandibular reconstruction. The benefit was most striking for large reconstructions requiring multiple fibular segments. Future directions include assessing the use of external registration devices to enhance surgical accuracy and to follow patients longitudinally to monitor the long-term benefit of VSP.

Two locus inheritance of non-syndromic midline craniosynostosis via rare SMAD6 and common BMP2 alleles

Premature fusion of the cranial sutures (craniosynostosis), affecting 1 in 2000 newborns, is treated surgically in infancy to prevent adverse neurologic outcomes. To identify mutations contributing to common non-syndromic midline (sagittal and metopic) craniosynostosis, we performed exome sequencing of 132 parent-offspring trios and 59 additional probands. Thirteen probands (7%) had damaging de novo or rare transmitted mutations in SMAD6, an inhibitor of BMP – induced osteoblast differentiation (p<10−20). SMAD6 mutations nonetheless showed striking incomplete penetrance (<60%). Genotypes of a common variant near BMP2 that is strongly associated with midline craniosynostosis explained nearly all the phenotypic variation in these kindreds, with highly significant evidence of genetic interaction between these loci via both association and analysis of linkage. This epistatic interaction of rare and common variants defines the most frequent cause of midline craniosynostosis and has implications for the genetic basis of other diseases. DOI: http://dx.doi.org/10.7554/eLife.20125.001

Temporal hollowing following surgical correction of unicoronal synostosis.

Background: Temporal hollowing occurs frequently following surgical correction of unicoronal synostosis. This is characterized by a depression in the posterolateral orbitotemporal region. Both soft-tissue and bony causes have been postulated to underpin this problem. The authors investigated the soft-tissue and bony morphology of the temporal region in surgically treated unicoronal synostosis patients. Methods: A retrospective analysis of adolescent patients with temporal hollowing who underwent unicoronal synostosis repair as infants was carried out. Demographic data and computed tomographic craniometric parameters were obtained and analyzed using the t test. Photographs were graded subjectively and compared with quantitative data. Results: Fifteen children (seven boys and eight girls; mean age, 13 years) were identified. Seventeen patients (10 boys and seven girls; mean age, 14 years) were used as controls. The affected side showed temporal constriction, compared with controls, along the supraorbit and anterior temple. The sella-to-pterion distance was also less, but not statistically so. Soft-tissue analysis revealed decreased thickness of the affected temporalis muscle compared with unaffected and control sides (range, 1 to 3 mm less). The affected fat pad width was not statistically different from unaffected and controls. Subjective clinical grading did not demonstrate statistical correlations with quantitative data. Conclusions: Temporal hollowing occurs following surgical correction of unicoronal synostosis, despite original overcorrection, because of bony constriction along the anterior bandeau. Decreased thickness of the temporalis muscle may also contribute to this depression, whereas the superficial fat pad does not play a role. Subjective clinical scoring does not strictly correlate with severity of craniometric measurements. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, III. Figure. No caption available.

An analysis of mandibular volume in hemifacial microsomia.

Background: The mandibular deformity in hemifacial microsomia is characterized by ramus-condyle unit deficiency. The Pruzansky score classifies the proximal mandible according to aberrant condylar-unit structure. The authors sought to volumetrically evaluate the hemifacial mandible compared with controls, and to assess for Pruzansky score correlation. Methods: This is a retrospective analysis of children with hemifacial microsomia. Demographic information was obtained, and computed tomographic data were analyzed by segmentation and volumetric calculations. Age-matched controls were compared using the t test. Results: Computed tomographic scans revealed 24 hemifacial and 13 controls: 62.5 percent right, 12.5 percent left, and 25 percent bilateral; and 34 percent type I, 28 percent type IIa, 16 percent type IIb, and 22 percent type III. Type IIb/III compared with type I/IIa were 11,100 and 17,773 mm3, respectively (p = 0.0029). Segmental evaluation of type IIb/III versus type I/IIa showed 3590 versus 6510 mm3 for the proximal segments (p = 0.0022) and 7449 versus 10,829 mm3 for the dental-bearing segments (p = 0.0221). All hemifacial microsomia hemimandibles (types I to III) were significantly less than controls: 14,837 versus 20,418 mm3 (p = 0.0005). Both dentate and proximal hemifacial microsomia segments statistically decreased in volume with increasing Pruzansky score. The dentate segment of the unaffected hemifacial microsomia side was statistically less than controls. Conclusions: This study volumetrically characterized the hemifacial microsomia mandibular deformity. As expected, with increasing Pruzansky severity, hemimandibular and proximal segment volumes declined. Unexpectedly, the hemifacial dentate segment also proved significantly diminished, corresponding to the degree of proximal volume loss.

Treacher collins syndrome.

Treacher Collins syndrome is a genetic disorder resulting in congenital craniofacial malformation. Patients typically present with downslanting palpebral fissures, lower eyelid colobomas, microtia, and malar and mandibular hypoplasia. This autosomal dominant disorder has a variable degree of phenotypic expression, and patients have no associated developmental delay or neurologic disease. Care for these patients requires a multidisciplinary team from birth through adulthood. Proper planning, counseling and surgical techniques are essential for optimizing patient outcomes. Here the authors review the features, genetics, and treatment of Treacher Collins syndrome.

Simulated surgery and cutting guides enhance spatial positioning in free fibular mandibular reconstruction

Introduction: The free fibular flap is the workhorse for mandibular reconstruction. Three‐dimensional (3D) planning, with use of cutting guides and prebent plates, has been introduced. The purpose of this study is to evaluate the interfragmentary gap size and symmetry between conventional freehand preparation versus those using 3D planning. Methods: A retrospective review was performed. Conventional free form and 3D planned fibular reconstructions performed by the senior authors at a single institution were included. Reconstructions were further subdivided into “body only” and “complex.” Demographic and intraoperative data were collected. Postoperative CT scans were analyzed using Materialize software. Interfragmentary gap distances (mm) and symmetry (degrees) were assessed. Results: Nineteen fibular reconstructions met inclusion criteria, ten conventional free form, and nine 3D planned reconstructions. Interfibular gaps measured 0.36 ± 0.50 mm in the 3D group versus 1.88 ± 1.09 mm in the non‐3D group (P = 0.004). Overall symmetry (a ratio between right and left angles) measured versus 1.027 ± 0.08 in the 3D‐planned versus 1.024 ± 0.09 in the non‐3D group in (P = 0.944). Within only mandibular body reconstructions, symmetry was similar between the two techniques: 1.05 ± 0.12 in the 3D group versus 0.97 ± 0.05 in the non‐3D group (P = 0.295). Conclusions: 3D planning lessens interfibular gap dimensions and may enhance axial symmetry. Space between native mandible and fibula is not appreciably altered using planning. Future efforts will focus on the accuracy and reproducibility of the 3D planned to actual results as well as clinical significance and efficiency benefits.

Bilateral orbital dysmorphology in unicoronal synostosis.

Background: Orbital dysmorphology is believed to cause ipsilateral ocular abnormalities in unicoronal synostosis. Recently, there has been increasing evidence of visual problems in the contralateral eye. The purpose of this study was to explore morphology of both the ipsilateral and contralateral unicoronal synostosis orbit. Methods: Demographic data and computed tomographic information were recorded. Three-dimensional computed tomographic renderings were created digitally and analyzed (SurgiCase). Craniometric analysis was conducted for orbital volume, horizontal and vertical orbital cone angle, orbital depth, and corneal projection. Results: Twenty-one unicoronal synostosis infants and 10 matched controls were examined. The orbital volume ratio between ipsilateral and contralateral sides was 93.8 ± 5.3 in unicoronal synostosis infants and 99.3 ± 2.1 (p = 0.001) in the control group. The horizontal orbital cone angle of the contralateral eye was significantly greater than that of both the ipsilateral side (p < 0.0001) and the control orbits (p = 0.0011, p = 0.0004). The vertical cone angle of the ipsilateral eye was significantly greater than that of the ipsilateral (p < 0.0001) and control orbits (p = 0.0326, p = 0.0030). There was no difference in orbital depth between ipsilateral and contralateral orbits. The ipsilateral globe projected 27 percent farther past the orbital aperture than the contralateral side. There was no difference between right and left orbits of a control in any analysis. Conclusions: In addition to ipsilateral orbital deformity, the contralateral orbit is highly dysmorphic. As orbital asymmetry may underlie visual abnormalities, future reconstructive efforts may necessitate bilateral correction. CLINICAL QUESTION/LEVEL OF EVIDENCE: Risk, II.

Assessment of three-dimensional nasolabial response to Le Fort I advancement

BACKGROUND Le Fort I advancement induces soft tissue changes to the nasolabial region. The correlation of sagittal skeletal movement to soft tissue alteration has been studied using 2D methods. However, the influence of maxillary advancement has not been adequately assessed using three-dimensional means. The purpose of this study is to analyze nasolabial changes following Le Fort I advancement using 3D photometric measurements. METHODS Patient demographic information and their amount of advancement were tabulated. Pre- and postoperative 3D photographs (3D VECTRA photosystem, Canfield, Fairfield, NJ) were recorded. Nasolabial anthropometric measurements were performed using the corresponding 3D post-processing software (Mirror). Six month minimum follow-up elapsed before final evaluation. RESULTS Forty-four 3D photo data sets were included. Mean maxillary advancement was 5.5 (±1.9) mm. Male/female ratio was 0.7 with a mean age of 16.7 years. Significant increases (p < 0.0001) were seen in the alar base, alar widths, nostril width, and in the soft triangle and lateral alar angles. Significant decreases (p < 0.0001) were noted in the nasofrontal angle and in nostril height. A significant (p < 0.05) increase of the nasal tip, columella and upper lip projection was seen. Philtral height showed no significant changes (p > 0.05) after maxillary advancement. No significant correlation (p > 0.05) between the degree of soft tissue changes and the amount of maxillary advancement was found. CONCLUSION Le Fort I advancement significantly impacts the nasolabial soft tissue envelope. The 3D soft tissue changes are predictable and similar for any advancement up to 10 mm.