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The post-condylar cartilage graft in the treatment of retrognathia - an assessment of stability and function.
Post-condylar cartilage grafts have been used to advance the mandible in 15 patients who have been followed up for periods varying from 5 to 37 months. Operative morbidity is minimal, but early displacement of the cartilage block occurred in two patients. Temporomandibular function appears unaffected, with condylar remodelling only demonstrated in two cases. Significant skeletal relapse has not been identified, but post-operative changes in incisor position usually occur and may prejudice the clinical result. Careful supervision is required to ensure orthodontic stability.
Correction of maxillary retrognathia in a case of craniometaphyseal dysplasia.
A Patient is reported in whom radiographs disclosed changes in the skull and long bones that were characteristic of craniometaphyseal dysplasia. Because of the deformity of the jaws (maximillary retrognathism), a horizontal osteotomy (Le Fort I procedure) was performed.
Mandibular Retrognathia and sleep apnea.
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Experimental aspects of the pathogenesis of Robin sequence.
OBJECTIVE: The Pierre Robin Sequence (PRS) is a good example of disturbed embryonic development of the secondary palate involving insufficient mandibular growth, failed forward tongue movement, and, in the case of a cleft, impeded fusion of the secondary palate. Discussion continues regarding which of the involved pathogenetic factors is the primary cause of the induced cascade of signs: insufficient mandibular growth or failed descent of the tongue. DESIGN: Forty-five randomly selected, 18-day-old formalin-fixed A/WySn mouse fetuses were investigated. The strain is known to have a basic genetic defect and as much as 44% clefts in the offspring. Twenty-four fetuses in the group had a cleft palate. Mandible position was measured relative to the head and to the presence or absence of a cleft. Cleft width and tongue position were also determined. Thirty-eight NMRI mouse fetuses of the same age served as controls. RESULTS: All A/WySn fetuses showed marked mandibular retrognathia, which was more severe in the cleft group (p < .05), but there was no correlation between the degree of retrognathia and cleft width. The median cleft width was 3.4 mm (1.6 through 6.3 mm). The tongue was in the cleft in all 12 fetuses with wide clefts (>3.4 mm wide), and free in the oral cavity in the other 12. Tongue position did not influence the degree of retrognathia (p < .05). Moreover, the tongue was free in all fetuses with severe retrognathia. CONCLUSION: The results support the primary role of retroposition of the mandible in the development of cardinal symptoms of Pierre Robin Sequence.
Midface prognathism in maxillonasal dysplasia (Binder's syndrome) determined by a theoretical midface ratio.
A theoretical midface ratio was determined from midface lengths and heights in straight lateral radiographs. Using regression analyses, the ratio was tested on 90 adults who did not have an aberrant anatomy of the maxilla. A linear relationship was found between the theoretical midface ratio and sella-nasion-point A (SNA), and the correlation was high (adjusted R2 = 82.7%). Limit values were determined using the theoretical midface ratio for the classifications of retrognathia, orthognathia, and prognathia. Conditional probabilities were estimated for classifications according to SNA for every classification by the theoretical midface ratio. Eighty percent of the subjects were identically classified by SNA and the theoretical midface ratio, and no subjects were placed differently in the extreme groups of retrognathia and prognathia. The theoretical midface ratio was then used to estimate the degree of prognathism in 35 adults with maxillonasal dysplasia. Less than half of the subjects had maxillary retrognathia, and the majority had an orthognathic or even prognathic maxilla. This is an indication that individualization of treatment objectives, including the consideration of mandibular setback operations to correct incisor crossbites, is equally important in maxillonasal dysplasia and in normal anatomy.
Accuracy of cephalometric and video imaging program Dentofacial Planner Plus in orthognathic surgical planning.
The prediction of profile changes after surgery poses a problem due to the variability of the soft tissue and the differences in soft-tissue translations relative to osseous changes. This study examined the accuracy of computer predictions of such soft-tissue changes. Twenty-five patients with mandibular retrognathia were examined before and after orthognathic surgery. Changes in soft-tissue reference points were correlated to translations of hard-tissue references in the sagittal and vertical planes, and the measurements from these patients were compared to results predicted in preoperative planning by the cephalometric and video imaging program Dentofacial Planner. In surgical treatment involving advancement of the mandible, the mean operative advancement of the osseous pogonion was 6.06 mm. The corresponding movements of soft-tissue references, expressed as percentages relative to the movement of the osseous pogonion in the sagittal plane, were 98.4% for the soft-tissue pogonion, 93.6% for the soft-tissue menton, and 49.0% for the soft-tissue labrale inferior. The same measurements were carried out in the vertical plane and the changes in soft-tissue references were compared to those predicted in preoperative planning using the Dentofacial Planner. The predicted images were perceived as agreeing with the actual image most frequently in the lip and nasal area, while the highest degree of error was seen in the submental region. An overall predictability of more than 80% can be attained by planning mandibular advancement operations for correction of mandibular retrognathia using the Dentofacial Planner.
Functional characteristics of retrognathic patients before and after mandibular advancement surgery.
PURPOSE: The purpose of this investigation was to compare morphologic parameters and functional performance between controls and a sample of patients with mandibular retrognathia prior to surgical correction, and to examine how oral motor function adapts after treatment. PATIENTS AND METHODS: Twenty-four retrognathic female patients were compared with 26 female controls before and up to 3 years after mandibular advancement surgery. Measures of skeletal morphology, mandibular range of motion, maximum isometric bite force, and levels of electromyographic activity in the anterior and posterior temporalis and masseter muscles during isometric bites were made on all subjects over time. One-way analysis of variance was used to compare the controls, the patients before surgery, and the patients after surgery. RESULTS: Surgical lengthening of the mandible averaged 7.3 mm, bringing most skeletal measures into the normal range. There were no significant differences in jaw muscle mechanical advantage between patients and controls before surgery, but surgery significantly reduced mechanical advantage of the anterior temporalis and masseter muscles. Jaw hypomobility was apparent at 6 weeks after surgery, but returned to normal values within 12 to 24 months. Before surgery the patients had maximum isometric bite forces less than half those of controls. Bite forces steadily increased after surgery, approaching normal values within 2 years. Before surgery the patients' muscle activity levels per unit of bite force were equivalent to those of controls or somewhat higher. After surgery some of the patients' muscles had significantly lower levels of muscle activity per unit of bite force than did controls. CONCLUSION: The results of this study suggest that correction of mandibular retrognathia by mandibular advancement surgery produces some significant functional benefits.
Pediatric internal derangements of the temporomandibular joint: effect on facial development.
To evaluate the relationship between internal derangement(s) of the temporomandibular joint(s) (TMJ) and disturbed facial skeleton growth (dysmorphogenesis), 128 consecutive children (103 girls, 25 boys), who were 14 years of age or younger and had undergone combined radiographic and magnetic resonance (MR) imaging studies of both TMJs, were retrospectively analyzed. Imaging studies had been performed to investigate suspected TMJ derangement because of symptoms that included, either individually or in various combinations, pain, mechanical TMJ dysfunction, and facial skeleton abnormalities, such as mandibular deficiency (particularly retrognathia) and lower facial (mandibular) asymmetry, manifested by chin deviation from the midline. Of these patients, 112 were found to have at least one internally deranged TMJ on imaging studies; in 85 patients, both TMJs were abnormal. Of the 60 retrognathic patients 56 were found to have TMJ derangement, generally bilateral and often of advanced stage. In cases of lower facial asymmetry, the chin was uniformly deviated toward the smaller or more degenerated TMJ. Both TMJs were normal in 16 patients, most of whom had normal facial structure. We conclude that TMJ derangements are both common in children and may contribute to the development of retrognathia, with or without asymmetry, in many cases.
Masticatory function in retrognathic patients, before and after mandibular advancement surgery.
PURPOSE: Mandibular retrognathia is a dentofacial deformity that can be surgically corrected. The purpose of this study was to evaluate the influence of orthognathic surgery on masticatory function in a sample of retrognathic patients and to compare these findings with those of controls. PATIENTS AND METHODS: Eleven retrognathic patients were tested before and 1 to 1.5 years after mandibular advancement surgery and compared with 12 controls. The median particle size after chewing a silicon rubber test food, the maximum bite force, and the electromyographic activity (EMG) of the anterior temporalis and the masseter muscles during isometric clenching and during chewing were determined. Patients, before and after treatment, and controls were statistically compared by analysis of variance. RESULTS: Surgical correction of mandibular retrognathia did not change chewing efficiency, maximum bite force, EMG during maximal clenching, EMG during chewing, or the EMG/bite-force relationship. Compared with controls, the chewing efficiency, maximum bite force, EMG during maximal clenching, and EMG during chewing values were lower. No difference for the EMG/bite-force ratio at maximal clenching was found, indicating similar muscle efficiency for patients and controls. However, in the range of 10% to 40% of the maximum bite force, the slope of the EMG/bite-force regression line was steeper for the patients than for the controls, indicating decreased muscle efficiency for patients. CONCLUSIONS: The results of this study suggest that in retrognathic patients, function of the masticatory system is impaired. Oral function was not influenced by mandibular advancement surgery.
Functional and morphologic changes after combined maxillary intrusion and mandibular advancement surgery.
PURPOSE: The purposes of this investigation were 1) to compare the morphology and function of patients with combined vertical maxillary excess (VME) and mandibular retrognathia with that of controls, and 2) to examine how these parameters change after combined maxillary intrusion and mandibular advancement surgery. PATIENTS AND METHODS: Fifteen female VME/retrognathic patients were compared with 26 female controls before and for up to 3 years after orthognathic surgery. Facial skeletal morphology, mandibular range of motion, maximum isometric bite force, and levels of electromyographic activity (EMG) in selected muscles of mastication were measured on all subjects. Where appropriate, one-way analysis of variance (ANOVA) or t-tests were used to compare the patients with controls. Univariate repeated-measures ANOVA was used to study longitudinal changes. RESULTS: Preoperatively, patients' morphologic measurements were characteristic of VME compounded by mandibular retrognathia. At surgery, the maxilla was elevated an average of 2.8 mm, and the mandible was lengthened by an average of 7.1 mm. All of the postoperative morphologic measurements were closer to normal values. The patients' masseter mechanical advantage was significantly lower than that of controls both before and after surgery. Surgically induced changes in mechanical advantage were very small. The patients' maximum range of motion and excursion during mastication were all lower than those of controls before surgery. All measurements of mobility decreased immediately after surgery, with a gradual return to preoperative values. However, even 3 years after surgery, all of the motion measurements remained smaller than those of the controls. Before surgery, the patients had maximum isometric bite forces significantly lower than those of controls. Bite forces increased significantly after surgery, approaching normal values within 2 years. The activity levels in the muscles of mastication during isometric bites were not significantly altered by surgery. CONCLUSIONS: This study confirms that VME/retrognathia patients suffer from substantial deficiencies in their oromotor function. Surgical correction of this particular type of dentofacial deformity improves both the morphologic and functional deficits. Although some changes were not statistically significant, all were toward normalization of the presurgical values.
Mandibular lengthening by distraction osteogenesis for treatment of obstructive sleep apnea syndrome: a case report.
A 31-year-old man who had been diagnosed with obstructive sleep apnea syndrome (OSAS) due to retrognathia was referred to our hospital. Before treatment, the angle of the sella-nasion-point B (SNB) was 67 degrees. The lowest oxygen saturation (SpO2) during sleep was 77%, the longest-running episode of sleep apnea was 128 seconds, and his apnea index (AI) was 29.9. He underwent bilateral horizontal mandibular distraction osteogenesis using intraoral distraction devices. After mandibular distraction, SNB increased to 72 degrees. The lowest SpO2 during sleep increased to 85%, the longest-running episode of sleep apnea decreased to 40 seconds, and his AI decreased to 4.1 (within normal range). No marked recurrence of OSAS was observed even at one year after mandibular distraction. This report suggests that mandibular lengthening by distraction osteogenesis is an effectual method for the treatment of OSAS due to retrognathia.
Obstructive sleep apnoea: a cephalometric study. Part I. Cervico-craniofacial skeletal morphology.
A comprehensive cephalometric analysis of cervico-craniofacial skeletal morphology in 100 male patients with obstructive sleep apnoea (OSA) and 36 male controls was performed. The significant aberrations in the OSA group feature: (1) shorter dimension of cranial base with slight counter-clockwise rotation and depression of clivus; (2) shorter maxillary length with normal height; (3) maxillo-mandibular retrognathia related to nasion perpendicular plane (N perpendicular FH) despite normal angles of prognathism; (4) 47 per cent of the OSA group had mandibular retrognathia; (5) increased anterior lower facial height and mandibular plane angle; (6) reduced size of bony pharynx; (7) inferiorly positioned hyoid bone at C4-C6 level; (8) deviated head posture with larger cranio-cervical angle. Cephalometric analysis is highly recommended in OSA patients as one of the most important tools in diagnosis and treatment planning.
Early craniofacial morphology and growth in children with bilateral complete cleft lip and palate.
PURPOSE: Analysis of craniofacial morphology and growth in children with bilateral complete cleft lip and palate (BCCLP), compared with a control group with unilateral incomplete cleft lip (UICL), before any treatment as well as 20 months after lip closure. MATERIAL: The children were drawn from a group representing all Danish children with cleft born 1976 to 1981. Sixty-four children were included in the study (19 BCCLP and 45 UICL). The ages were 2 and 22 months at examinations 1 and 2, respectively. METHOD: The method of investigation was infant cephalometry in three projections. The craniofacial morphology was analyzed using linear, angular, and area variables. Growth was defined as the displacement vector from the coordinate of the corresponding landmark in the x-ray at examination 1 to its coordinate at examination 2, corrected for x-ray magnification. The growth of an anatomical region in a patient was assessed by investigating the growth pattern formed by a collection of individual growth vectors in that region. RESULTS: The BCCLP group differed significantly from the UICL group. The most striking findings in BCCLP were an extremely protruding premaxilla; markedly increased posterior maxillary width; increased width of the nasal cavity; short maxilla with reduced posterior height; short mandible; bimaxillary retrognathia; severe reduction in the size of the pharyngeal airway; and a more vertical facial growth pattern. CONCLUSION: Our findings indicate that a facial type including a wide and posterior short maxilla, short mandible, and bimaxillary retrognathia might be a liability factor that increases the probability of developing cleft lip and palate.
Post-traumatic TMJ internal derangement: impact on facial growth (findings in a pediatric age group).
Many clinical studies have shown how jaw injuries sustained during impact trauma to the face or mandible are the single most important cause of TMJ subsequent internal derangement. Proper function of the masticatory system is certainly the most influential variable in the TMJ remodelling; once a TMJ is internally deranged, adaptative or degenerative osteocartilagineous processes take place in the mandible, temporal bones and muscles. To evaluate relationships between consequences of post-traumatic TMJ internal derangement and disturbed facial skeleton growth in children, 25 patients (16 boys 9 girls), 14 year of age or younger, were selected out of a group of 74 and analysed. They all had been treated by physiotherapy and had undergone combined clinical and radiographic examination for five years. Symptoms included either individually or in various combination, pain, mechanical TMJ dysfunction and facial skeletal abnormalities, such as mandibular retrognathia and lower facial asymmetry manifested by chin deviation from the midline. Seventeen patients were found to have at least one abnormal and internally deranged TMJ on imaging studies; in twelve of them a mandibular asymmetry with chin deviation from the midline to the smaller or more degenerated TMJ was evident. Of the eight retrognathic patients, five were found to have bilateral TMJ derangement. In three patients both TMJ(s) were normal with normal facial structure. These data suggest that TMJ derangement in children may potentially have an impact on facial growth and lead to the development of retrognathia, with or without asymmetry, in many cases.
Temporomandibular disorders in juvenile chronic arthritis patients. A clinical study.
In a prospective study, 105 children with juvenile chronic arthritis (JCA) were clinically and radiographically examined. The aim was to investigate the distribution of symptoms and clinical signs of temporomandibular disorders and to study correlations with radiographic mandibular condylar lesions. The present material appeared to be a representative sample of Swedish JCA children with respect to the distribution of genders and JCA subtypes as well as the peak of onset of the disease. Symptoms from the masticatory system were common (26%) and pain at mandibular function and stiffness at mouth opening the most frequent ones. Restricted maximal voluntary mouth opening (MVM) was the most frequent clinical finding. Radiographic condylar lesions, frequently found in the present material (39%), were significantly correlated with postnormal occlusion, restricted MVM, anterior open bite and mandibular retrognathia. However, most of the JCA children with radiographic condylar lesions did not present with symptoms from the masticatory system, postnormal occlusion, restricted MVM, anterior open bite or mandibular retrognathia.
Chromosome 10p11.2-p12.2 duplication: report of a patient and review of the literature.
We report on a young male with mental retardation, slightly upslanting palpebral fissures, strabismus, high-arched palate, retrognathia, and flat feet. Cytogenetic analysis in addition to fluorescent in situ hybridization (FISH) and comparative genomic hybridization (CGH) showed the presence of a chromosome 10p11.2-->p12.2 duplication. Karyotypes of the parents were normal. Comparison of the clinical findings observed in the present patient with those observed in other reported cases with duplication 10p suggest that the presence of high arched/cleft palate and retrognathia may be related to the 10p11.2-->p12.2 duplication. Also, no critical region for the trisomy 10p syndrome has been delimited.
Airway management of the severely retrognathic child: use of the laryngeal mask airway.
Successful airway management of an infant or child with moderate to severe retrognathia first requires recognition of a potential problem. If the child cannot be intubated in a standard fashion, the use of a laryngeal mask airway (LMA) should be considered. We describe two cases wherein a toddler and an infant with severe retrognathia failed multiple attempts at traditional intubation. Both had an anterior larynx and hypoplasia of the mandible. In both cases, a subsequent LMA was successfully placed. The severely retrognathic newborn or child presents to the physician a unique challenge in airway management. Techniques to manage this difficult pediatric airway are different from those used in the adult. Otolaryngologists should be aware of this intubation technique and include it in their armamentarium of airway-management strategies. The LMA is not recommended as the technique of choice for securing a difficult airway, but it is an effective alternative when indicated, and it might be life-saving.