Biomedical subjects

Daniel P Govier

Publications and source records attributed to Daniel P Govier.

5 recordsLinked to original sources

PubMed2006

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.

Anthropometry↗

PubMed2006

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.

Adolescent↗

PubMed2005

Os parietale divisum.

Divisions of the parietal bone are extraordinarily rare, and have been described previously only in skull specimens in the anatomical literature. We report a case of os parietale divisum (divided parietal bone) in an infant with plagiocephaly. A 36-weeks gestation male with multiple congenital anomalies presented to the deformational plagiocephaly clinic at 11 weeks of age. CT imaging demonstrated a suture dividing the left parietal bone into two segments. He had a plagiocephalic appearance, with the greater occipital and parietal protuberances ipsilateral to the abnormal left parietal suture, and a correspondingly flatter right occiput. Head circumference was in the normal range, and the anterior fontanelle was patent and of normal size. He had mild right-sided right frontal and malar protuberance. Mandibular asymmetry was noted with a chin-point to the right of midline. He had a left-sided head tilt. He was treated with cranial molding helmet therapy for his head shape and physical therapy for his head tilt. After 16 months of helmet therapy, he had little improvement of his head shape. This case is an in vivo presentation of a rare variant, os parietale divisum.

Abnormalities, Multiple↗

PubMed2004

Accuracy in identification of patients with 22q11.2 deletion by likely care providers using facial photographs.

Numerous facial characteristics are associated with velocardiofacial syndrome. Care providers may use these facial characteristics to identify patients who may benefit from fluorescence in situ hybridization genetic testing to determine the presence of the 22q11.2 deletion. The purpose of this study was to test the hypothesis that experienced care providers were able to correctly diagnose the 22q11.2 deletion on the basis of studying frontal facial photographs. After approval was obtained from the human studies committee, patients who had undergone fluorescence in situ hybridization genetics testing for the presence of a 22q11.2 deletion were asked to submit two frontal photographs: one at infancy and one beyond the second birthday. These photographs were randomized, made anonymous, and then placed on a secure Web site. Specialists in the fields of plastic surgery, otolaryngology, genetics, and speech pathology were asked to evaluate their experience and confidence levels in diagnosing a 22q11.2 deletion and were then asked to rate the photographs by likelihood of deletion using a five-point Likert scale. Thirty-two specialists (10 surgeons, nine geneticists, and 13 speech pathologists) participated in the study. On the basis of clear responses, respondents predicted the presence (sensitivity) and absence (specificity) of the 22q11.2 deletion at chance levels. Of the remaining responses, 20 to 25 percent were unsure and 20 to 25 percent were clearly wrong. When an unsure response was treated as a weak positive, the results favored sensitivity slightly, with a sensitivity of 70 percent and a specificity of 50 percent. Sensitivity improved somewhat with experience, as measured by the number of patients seen per year. The prediction of the presence or absence of the 22q11.2 deletion at chance levels suggests that the ability to diagnose on the basis of appearance alone is not a sufficient diagnostic tool. Although the ability does increase with experience, it is of statistical but not clinical significance.

Abnormalities, Multiple↗

PubMed2004

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.

Child, Preschool↗