Effect of a Syndromic Diagnosis on Mandibular Size and Sagittal Position in Robin Sequence

Rogers, Gary; Lim, Asher A.T.; Mulliken, John B.; Padwa, Bonnie L.

doi:10.1016/j.joms.2009.06.010

« Previous Next »Journal of Oral and Maxillofacial Surgery
Volume 67, Issue 11 , Pages 2323-2331, November 2009

Effect of a Syndromic Diagnosis on Mandibular Size and Sagittal Position in Robin Sequence

Gary Rogers, MD, JD, MBA, MPH
- Assistant Professor of Surgery, Department of Plastic and Oral Surgery, Children's Hospital Boston, Harvard Medical School, Boston, MA
Asher A.T. Lim, BDS, MDS
- Fellow, Department of Plastic and Oral Surgery, Children's Hospital Boston, Harvard Medical School, Boston, MA
John B. Mulliken, MD
- Professor of Surgery, Department of Plastic and Oral Surgery, Children's Hospital Boston, Harvard Medical School, Boston, MA
Bonnie L. Padwa, DMD, MD
- Associate Professor of Oral and Maxillofacial Surgery, Department of Plastic and Oral Surgery, Children's Hospital Boston, Harvard Medical School, Boston, MA
- Address correspondence and reprint requests to Dr Padwa: Department of Plastic and Oral Surgery, Children's Hospital, 300 Longwood Avenue, Boston, MA 02115

Purpose

Despite its pathogenic heterogeneity, it is often assumed that the small mandible in a neonate with Robin sequence will not grow normally. The purpose of this study was to determine mandibular length and position in patients with nonsyndromic versus syndromic Robin sequence.

Patients and Methods

Lateral cephalograms of 51 children with Robin sequence were analyzed. Group I consisted of nonsyndromic (NS) subjects and group II consisted of subjects with the 4 most common syndromic (S) diagnoses. Cephalometric measurements included sella-nasion-A point (SNA), sella-nasion-B point (SNB), sella-nasion-pogonion (SNPg), articulare-gonion-pogonion (ArGoPg), temporomandibular joint-pogonion (TmPg), articulare-gonion (ArGo), and gonion-pogonion (GoPg). Differences between groups and subgroups were compared using t test.

Results

There were 26 NS patients (mean age, 6.8 yrs) and 25 S patients (mean age, 8.7 yrs); mean age was statistically different between groups (P = .04); therefore, cephalometric measurements were compared with age-matched normal values. Syndromes included Stickler (n = 10), bilateral facial microsomia (n = 8), velocardiofacial (n = 4), and Treacher Collins (n = 3). SNA was statistically different from normal in both groups (NS, P = .017; S, P = .007); however, SNB was not different from normal for either group (NS, P = .175; S, P = .537). SNPg (0.007) was significantly greater than normal in NS (P = .007) but not in S (P = .702) patients. SNA, SNB, and SNPg were not significantly different between groups. In both groups, mandibular length was short (P = .00), especially in S patients (P = .049), mandibular body was small (NS, P = .00; S, P = .00), and the gonial angle more obtuse (NS, P = .006; S, P = .000) than normal. Ramus length was significantly shorter than normal only in S patients (P = .019). Mandibular length (TmPg) was smaller than normal in all S subgroups but with wide variability. There were statistically significant differences among S subgroups with respect to mandibular sagittal position (SNB, P = .00; SNPg, P = .00) and mandibular length (TmPg, P = .008). There were no differences in S subgroups with respect to age, SNA, ArGo, GoPg, and ArGoPg.