Daniel Govier

Anthropometric precision and accuracy of digital three-dimensional photogrammetry: comparing the Genex and 3dMD imaging systems with one another and with direct anthropometry.

A variety of commercially available three-dimensional (3D) surface imaging systems are currently in use by craniofacial specialists. Little is known, however, about how measurement data generated from alternative 3D systems compare, specifically in terms of accuracy and precision. The purpose of this study was to compare anthropometric measurements obtained by way of two different digital 3D photogrammetry systems (Genex and 3dMD) as well as direct anthropometry and to evaluate intraobserver precision across these three methods. On a sample of 18 mannequin heads, 12 linear distances were measured twice by each method. A two-factor repeated measures analysis of variance was used to test simultaneously for mean differences in precision across methods. Additional descriptive statistics (e.g., technical error of measurement [TEM]) were used to quantify measurement error magnitude. Statistically significant (P < 0.05) mean differences were observed across methods for nine anthropometric variables; however, the magnitude of these differences was consistently at the submillimeter level. No significant differences were noted for precision. Moreover, the magnitude of imprecision was determined to be very small, with TEM scores well under 1 mm, and intraclass correlation coefficients ranging from 0.98 to 1. Results indicate that overall mean differences across these three methods were small enough to be of little practical importance. In terms of intraobserver precision, all methods fared equally well. This study is the first attempt to simultaneously compare 3D surface imaging systems directly with one another and with traditional anthropometry. Results suggest that craniofacial surface data obtained by way of alternative 3D photogrammetric systems can be combined or compared statistically.

Central nervous system phenotypes in craniosynostosis

Though reduction in the number of cranial elements through loss of a suture is a recognized trend in vertebrate evolution, the premature closure of cranial sutures in humans, craniosynostosis, is considered a pathological condition. Previous research on craniosynostosis has focused primarily on the skeletal phenotype, but the intimate relationship between the developing central nervous system (CNS) and skull is well documented. We investigate the morphology of the CNS in patients with isolated craniosynostosis through an analysis of cortical and subcortical features using 3‐D magnetic resonance images (MRI). Results show that a distinct CNS phenotype can be defined for specific diagnostic categories. Many differences in CNS morphology observed in the patient samples may be anticipated based on skeletal morphology, but others are not reflected in the skull. We propose a developmental approach to determining the cause of premature suture fusion, which includes investigation of the craniofacial complex as a system, rather than study of isolated tissues.

Helmet Versus Active Repositioning for Plagiocephaly: A Three-Dimensional Analysis

BACKGROUND AND PURPOSE: Orthotic helmets and active repositioning are the most common treatments for deformational plagiocephaly (DP). Existing evidence is not sufficient to objectively inform decisions between these options. A three-dimensional (3D), whole-head asymmetry analysis was used to rigorously compare outcomes of these 2 treatment methods. PATIENTS AND METHODS: Whole-head 3D surface scans of 70 infants with DP were captured before and after treatment by using stereophotogrammetric imaging technology. Helmeted (n = 35) and nonhelmeted/actively repositioned (n = 35) infants were matched for severity of initial deformity. Surfaces were spatially registered to a symmetric template, which was deformed to achieve detailed right-to-left point correspondence for every point on the head surface. A ratiometric asymmetry value was calculated for each point relative to its contralateral counterpart. Maximum and mean asymmetry values were determined. Change in mean and maximum asymmetry with treatment was the basis for group comparison. RESULTS: The helmeted group had a larger reduction than the repositioned group in both maximum (4.0% vs 2.5%; P = .02) and mean asymmetry (0.9% vs 0.5%; P = .02). The greatest difference was localized to the occipital region. CONCLUSIONS: Whole-head 3D asymmetry analysis is capable of rigorously quantifying the relative efficacy of the 2 common treatments of DP. Orthotic helmets provide statistically superior improvement in head symmetry compared with active repositioning immediately after therapy. Additional studies are needed to (1) establish the clinical significance of these quantitative differences in outcome, (2) define what constitutes pathologic head asymmetry, and (3) determine whether superiority of orthotic treatment lasts as the child matures.

The Craniofacial Phenotype of the Crouzon Mouse: Analysis of a Model for Syndromic Craniosynostosis Using Three-Dimensional MicroCT

Objective: To characterize the craniofacial phenotype of a mouse model for Crouzon syndrome by a quantitative analysis of skull morphology in mutant and wild-type mice and to compare the findings with skull features observed in humans with Crouzon syndrome. Methods: MicroCT scans and skeletal preparations were obtained on previously described Fgfr2C342Y/+ Crouzon mutant mice and wild-type mice at 6 weeks of age. Three-dimensional coordinate data from biologically relevant landmarks on the skulls were collected. Euclidean Distance Matrix Analysis was used to quantify and compare skull shapes using these landmark data. Results: Obliteration of bilateral coronal sutures was observed in 80% of skulls, and complete synostosis of the sagittal suture was observed in 70%. In contrast, fewer than 40% of lambdoid sutures were found to be fully fused. In each of the 10 Fgfr2C342Y/+ mutant mice analyzed, the presphenoid-basisphenoid synchondrosis was fused. Skull height and width were increased in mutant mice, whereas skull length was decreased. Interorbital distance was also increased in Fgfr2C342Y/+ mice as compared with wild-type littermates. Upper-jaw length was shorter in the Fgfr2C342Y/+ mutant skulls, as was mandibular length. Conclusion: Skulls of Fgfr2C342Y/+ mice differ from normal littermates in a comparable manner with differences between the skulls of humans with Crouzon syndrome and those of unaffected individuals. These findings were consistent across several regions of anatomic interest. Further investigation into the molecular mechanisms underlying the anomalies seen in the Crouzon mouse model is currently under way.

Relationship of brain and skull in pre- and postoperative sagittal synostosis

Models of vertebrate skull evolution stress the coordinated developmental relationship between the skull and the brain that it houses. This study investigates the relationship between altered skull morphology and brain morphology in premature fusion of the cranial sagittal suture (isolated sagittal synostosis; ISS), a condition associated with dysmorphology of both neurocranium and brain. Although the skull displays a more normal shape following reconstructive cranial vault surgery, effects of this surgery on the brain have not been investigated. Landmark coordinate data were collected from three‐dimensional magnetic resonance imaging reconstructions of the brain in a sample of ISS patients and an age‐matched unaffected cohort. These data were analysed using Euclidean distance matrix analysis (EDMA). Results show that the brain in ISS is dysmorphic preoperatively, displaying a posteriorly directed neural expansion that does not ‘worsen’ with growth. Postoperatively, the brain in ISS displays a more globular shape overall as compared with the preoperative morphology, but differs from normal in its subcortical morphology. These results show that the ISS brain is altered following neurocranial surgery, but does not more closely approximate that of unaffected individuals. This suggests that although the brain is affected by manipulation of the skull, it retains a growth pattern that is, at least in part, independent of the skull.

Videofluoroscopic and Nasendoscopic Correlates of Speech in Velopharyngeal Dysfunction

Objective To compare videonasendoscopy, lateral videofluoroscopy, and perceptual speech examination in the assessment of velopharyngeal dysfunction. Design Retrospective observational. Setting Multidisciplinary cleft palate team at a tertiary academic institution. Patients, Participants Patients who had undergone videonasendoscopy and lateral videofluoroscopy for suspected velopharyngeal dysfunction at our center were evaluated. Inclusion required that videonasendoscopy, lateral videofluoroscopy, and the perceptual speech exam were performed on the same day. A total of 88 patients were analyzed. Main outcome Measure(s) Primary outcome measures included percent closure on videonasendoscopy, percent closure on lateral videofluoroscopy, and quantitative scores for hypernasal resonance, nasal emission, and facial grimace. Additional outcome measures included linear and angular anatomic measurements obtained from lateral videofluoroscopy. Results Moderately strong correlation was found between closure estimates of videonasendoscopy and lateral videofluoroscopy (ρ = .583; p < .001). Lateral videofluoroscopy estimates of closure averaged 11.7% higher than videonasendoscopy. Closure correlated moderately with overall speech severity (ρ = .304; p = .005); whereas, a stronger correlation was seen with hypernasal resonance (ρ = –.479; p < .001). Patients exhibiting grimace had worse closure than those without (79.1% versus 70.7%; ρ = .035). Movement angle of the velum and change in genu angle correlated significantly with closure function (ρ = –.304; p = .034 and ρ = –.395; p < .001, respectively). Conclusions Videonasendoscopy and lateral videofluoroscopy closure estimates correlated moderately. Lateral videofluoroscopy tended to give smaller gap estimates. Hypernasal resonance and facial grimace are useful clinical indicators of large gap size. Velar movement angle and change in genu angle were identified as anatomical correlates of closure function.

The craniofacial anomalies archive at St. Louis Children's Hospital: 20 years of craniofacial imaging experience.

&NA; This article describes how the Craniofacial Imaging Laboratory at the Cleft Palate and Craniofacial Deformities Institute, St. Louis Childrens Hospital, Washington University Medical Center, has developed an electronic archive for the storage of computed tomography image digital data that is independent of scanner hardware and independent of units of storage media (i.e., floppy disks and optical disks). The archive represents one of the largest repositories of high‐quality computed tomography data of children with craniofacial deformities in the world. Archiving reconstructed image data is essential for comparative imaging, surgical simulation, quantitative analysis, and use with solid model fabrication (e.g., stereolithography). One tertiary craniofacial centers experience in the establishment and maintenance of such an archive through three generations of storage technology is reported. The current archive is housed on an external 35‐GB hard drive attached to a Windows‐based desktop server. Data in the archive were categorized by specific demographics into groups of patients, number of scans, and diagnoses. The Craniofacial Imaging Laboratory archive currently contains computed tomography image digital data for 1827 individual scans. The earliest scan was done in 1980; the most recently stored scan for the purposes of this report occurred in May of ‘2000. The average number of scans archived per complete year was 94, with a range of 59 to 138. Of the 1827 total scans, 74 percent could be classified into specific diagnostic categories. The majority of the archive (55 percent) is composed of the following five diagnoses: sagittal synostosis (17 percent), unilateral coronal synostosis (11 percent), hemifacial microsomia (10 percent), plagiocephaly without synostosis (10 percent), and metopic synostosis (7 percent). Storage of computed tomography image data in a digital archive currently allows for continuous upgrading of image display and analysis and facilitates longitudinal and cross‐sectional studies, both intramural and extramural. Internet access for clinical and research purposes is feasible, but contingent on protection of patient confidentiality. The future of digital imaging regarding craniofacial computed tomography scan storage and processing is also discussed. (Plast. Reconstr. Surg. 108: 1862, 2001.)

Long-term osseous morphologic outcome of surgically treated unilateral coronal craniosynostosis

Background: Unilateral coronal craniosynostosis has characteristic osseous dysmorphology that persists into adulthood if untreated. Knowledge of the long-term in vivo osseous morphologic outcome of surgically treated unilateral coronal craniosynostosis patients is limited. The purpose of this study was to define the osseous morphology of adolescent patients who underwent surgery for unilateral coronal craniosynostosis in infancy, compared with both their 1-year postoperative morphology and the morphology of other individuals with untreated unilateral coronal craniosynostosis. Methods: Three populations of unilateral coronal craniosynostosis were studied: group 1, patients with surgical treatment of unilateral coronal craniosynostosis in infancy who had reached dentoskeletal maturity, ranging in age from 13.5 to 32.7 years (n= 9); group 2, individuals with untreated unilateral coronal craniosynostosis, ranging in age from 1.1 to 21 years (n= 11); and group 3, a subset of group 1 patients 1 year after surgical correction of unilateral coronal craniosynostosis, ranging in age from 1.2 to 2.6 years (n= 6). Data from high-resolution, thin-slice computed tomographic scans of the head were analyzed. Thirty-five reproducible osseous landmarks were recorded as three-dimensional coordinates using ETDIPS imaging software. Nonmidline landmarks were designated as either ipsilateral or contralateral to the synostosis. One researcher performed all landmarking with high intrarater reliability (average error, <2 mm). Data from the three groups were analyzed for asymmetry using Euclidean distance matrix analysis techniques. Results: Euclidean distance matrix analysis asymmetry analysis demonstrated more statistically significant ipsilateral-contralateral asymmetric pairs in group 1 (68 of 135) than in group 3 (25 of 135), but fewer statistically significant ipsilateral-contralateral asymmetric pairs than in group 2 (93 of 135). Conclusions: Surgical treatment of unilateral coronal craniosynostosis in infancy results in a less asymmetric craniofacial skeleton in adolescence than nontreatment. However, patients who have been followed to dentoskeletal maturity have a greater degree of asymmetry than those evaluated at 1 year postoperatively. These results support the conclusion that with time there is a partial reversion to the untreated phenotype.

Coronal ring involvement in patients treated for unilateral coronal craniosynostosis.

The etiopathology of the clinical entity normally referred to as unilateral coronal synostosis is commonly used to connote unilateral fusion of the frontoparietal suture. However, other sutures in the coronal ring may exhibit synostosis concomitant with or independent from frontoparietal synostosis and give rise to similar clinical phenotypes. This study retrospectively analyzes high-resolution computed tomographic data sets to determine patency of sutures within the coronal ring. Computed tomographic scan digital data from 33 infants who subsequently underwent surgical correction of unilateral coronal synostosis were assessed for sutural patency using Analyze imaging software. The frontosphenoidal suture was subdivided into intraorbital frontosphenoidal and extraorbital frontosphenoidal portions, and the patency of the frontoethmoidal suture was also assessed. Patients were sorted into two groups on the basis of the status of their frontosphenoidal sutures: group 1 had patent frontosphenoidal but synostotic frontoparietal sutures (n = 21) and group 2 had both frontosphenoidal and frontoparietal synostoses. Observer reproducibility was tested. The vertical and horizontal dimensions of the bony orbit and the endocranial base deflection angle were measured with the observer blinded with regard to sutural status group. Frontoethmoidal synostosis was not noted in any patients in either group. Two patients had no frontoparietal suture synostosis with isolated intraorbital frontosphenoidal and extraorbital frontosphenoidal suture closures. Suture diagnosis reproducibility was 99 percent. In group 1, the ipsilateral-to-contralateral vertical orbit dimension ratio averaged 1.11, whereas in group 2 it averaged 1.04 (p < 0.05). The ratio of horizontal orbit measurements was not significantly different between groups. In both groups, the endocranial base was deflected ipsilateral to the synostotic frontoparietal suture, with an average angle of 12 degrees in group 1 and 17 degrees in group 2 (p < 0.005). The extent of synostosis along the coronal sutural ring contributes to the dysmorphology of the orbit and the endocranial base deflection in patients whose clinical phenotypic diagnosis is unilateral coronal synostosis.

Comparison of perceptions and treatment practices between neurosurgeons and plastic surgeons for infants with deformational plagiocephaly.

OBJECT Deformational plagiocephaly (DP) is the leading cause of head shape abnormalities in infants. Treatment options include conservative measures and cranial molding. Pediatric neurosurgeons and craniofacial plastic surgeons have yet to agree on an ideal therapy, and no definable standards exist for initiating treatment with helmets. Furthermore, there may be differences between specialties in their perceptions of DP severity and need for helmet therapy. METHODS Requests to participate in a web-based questionnaire were sent to diplomates of the American Board of Pediatric Neurological Surgery and US and Canadian members of the Pediatric Joint Section of the American Association of Neurological Surgeons and the Congress of Neurological Surgeons and the American Cleft Palate-Craniofacial Association. Questions focused on educational background; practice setting; volume of DP patients; preferences for evaluation, treatment, follow-up; and incentives or deterrents to treat with helmet therapy. Six examples of varying degrees of DP were presented to delineate treatment preferences. RESULTS Requests were sent to 302 neurosurgeons and 470 plastic surgeons, and responses were received from 71 neurosurgeons (24%) and 64 plastic surgeons (14%). The following responses represented the greatest variations between specialties: 1) 8% of neurosurgeons and 26% of plastic surgeons strongly agreed with the statement that helmet therapy is more beneficial than conservative therapy (p < 0.01); and 2) 25% of neurosurgeons and 58% of plastic surgeons would treat moderate to severe DP with helmets (p < 0.01). CONCLUSIONS Survey responses suggest that neurosurgeons are less likely to prescribe helmet therapy for DP than plastic surgeons. Parents of children with DP are faced with a costly treatment decision that may be influenced more strongly by referral and physician bias than medical evidence.