Change in cranio-cervical angulation following orthognathic surgery

Changes in natural head posture (NHP) were investigated in 33 patients (10 males, 23 females) with an age range of 16-40 years (median 21 years) following orthognathic surgery to change vertical face height. The reproducibility of the radiographer's technique of taking radiographs in NHP was investigated using a photographic method and found to be acceptable. The patients were divided into two groups: group 1, patients who had more than 3 mm of vertical change in anterior total face height (ATFH) and group 2, those who had less than 3 mm vertical change.For group 1 there was a significant relationship between ATFH change and cranio-cervical angulation (NSL/OPT) change (r = 0.532, P = 0.023), compared with group 2 (r = -0.247, P = 0.376). A similar relationship was revealed between lower anterior face height (LAFH)/ATFH ratio and NSL/OPT, where the correlation was also higher in group 1 (r = -0.635, P = 0.005) compared with group 2 (r = -0.182, P = 0.515). The correlation between cranio-vertical angulation (NSL/VER) and ATFH was not significant for group 1 (r = 0.406) or group 2 (r = 0.239) patients. Additionally, NSL/VER and LAFH/ATFH correlation for the two groups was not significant (r = -0.392 and -0.338, respectively).There appears to be a relationship between the reduction in vertical face height following orthognathic surgery and neck posture (as indicated by NSL/OPT). As no significant relationship was found between the reduction in face height and head posture (as indicated by NSL/VER) this suggests that neck posture, rather than head posture, had changed.     

Effects of neuromuscular deprogramming on the head position

Objectives:

The aim of this study was to evaluate the effects of the neuromuscular deprogramming of the mandible on the craniocervical position.

Methods:

Participants (n?=?65) were separated into two groups: 25 untreated controls (10 men and 15 women) and 40 patients (17 men and 23 women) and underwent neuromuscular deprogramming with upper occlusal splints for an average of 6 months and 7 days, before orthodontic treatment. Lateral cephalograms were obtained from each subject in the natural head position (NHP), before and after neuromuscular deprogramming. Craniocervical cephalometric analysis was performed to evaluate craniovertical (NSL/VER), craniocervical (OPT/NSL and CVT/NSL), and cervicohorizontal (OPT/HOR and CVT/HOR) angulation, and the angle of the cervical curvature (OPT/CVT).

Results:

After neuromuscular deprogramming, significant changes in three angles — NSL/VER (P<0·001), OPT/NSL (P<0·001) and CVT/NSL (P<0·001) — were found between the two groups. For the cervical spine position, no significant changes were observed.

Conclusion:

The results indicate that neuromuscular deprogramming using occlusal splint causes significant extension of the head.     

Changes in natural head position observed immediately and one year after rapid maxillary expansion

Rapid maxillary expansion (RME) has been shown to increase nasal permeability and reduce nasal airway resistance. A number of studies have examined the relationship between RME and the change in airway resistance, or the relationship between airway resistance and natural head position (NHP). Few studies, to date, have examined the relationship between RME and the change in NHP resulting from the consequent change in airway resistance. A sample of 43 adolescent patients with uni- or bilateral crossbite in the permanent dentition underwent RME as part of normal orthodontic treatment. Cephalograms in NHP were taken before, immediately after expansion, and one year after RME. No significant changes in the craniofacial angles were observed immediately after expansion. One year post-expansion, however, NSL/VER had reduced by 3.14 degrees (P < 0.01), OPT/HOR by 2.13 degrees (P < 0.05), and CVT/HOR by 2.55 degrees (P < 0.05). The results of this study suggest an ongoing change in head posture possibly due to a change in the mode of breathing from oral to nasal as a result of RME, thereby contributing to a change in craniofacial development, supporting and adding to the soft tissue stretching hypothesis.     

Surgical mandibular setback and changes in uvuloglossopharyngeal morphology and head posture: a short- and long-term cephalometric study in males

A detailed cephalometric analysis was conducted on a sample of 31 adult males who underwent correction of mandibular prognathism by mandibular setback osteotomy (BSRO) with rigid fixation to evaluate the changes in uvuloglossopharyngeal morphology, hyoid bone position and head posture. Lateral cephalograms were obtained 1-3 days prior to the operation and at standardized 6 months and 3 years post-operative follow-up. Statistical evaluation was performed by paired Student's t-test and Pearson product moment correlation analysis. Inferior position of the hyoid bone (AH perpendicular FH, AH perpendicular ML, AH perpendicular S) and valeculla (V perpendicular FH) was recorded at the 6-month follow-up, a transient finding as at 3 years almost complete recovery to their pre-surgical position was noted. No posterior displacement of the above structures (AH-C3 Hor, V-C3) was recorded. Soft palate length (pm-U) was increased and maintained at the long-term follow-up while its posture (NL/pm-U) became less upright. The tongue showed increased length (V-T) and sagittal area (TA) and a more upright posture (VT/FH) at the late follow-up. Increased contact length between tongue and the soft palate (CL) and less residual oropharyngeal area [area not occupied by soft tissues, (TA + SPA)/OPA] was found at the long-term follow-up. Craniocervical agulation (NSL/OPT, NSL/CVT) was increased indicating cervical hyperflexion at the 3-year follow-up. Reduction of the sagittal dimension of the oropharyngeal airway space (U-MPW) appeared at the first follow-up and was sustained at the longest follow-up which, in conjunction with the decrease in residual oropharyngeal area, could raise questions regarding airway patency after mandibular setback osteotomy.     

Relationships of sagittal skeletal discrepancy,natural head position,and craniocervical posture in young Chinese children

Objective: The aim of this study was to investigate the relationships of sagittal skeletal discrepancy, natural head position (NHP), and craniocervical posture in young Chinese children with average vertical facial pattern.

Methods: Ninety patients with average Frankfort mandibular plane angle (FH/ML) were classified into skeletal class I, II, and III relationships according to their ANB angle. Cephalometric radiographs in NHP were taken. Variables representing sagittal and vertical craniofacial morphology, head posture, and craniocervical posture were measured and compared.

Results: Subjects in the skeletal class II group showed the largest craniovertical angles and craniocervical angles, while subjects in the skeletal class III group exhibited the smallest craniovertical angles and craniocervical angles, though not all the measurements showed significant differences. The angle formed by the nasion-sella line and the tangent to the posterior border of the mandibular ramus (NSL/RL) was largest in the skeletal class II group and smallest in the skeletal class III group (p?=?0.05).

Discussion: Significant differences exist in NHP and craniocervical posture among skeletal class I, II, and III relationships in young Chinese children. Subjects with skeletal class II relationship tended to exhibit more extended head, and children with skeletal class III relationship often exhibited flexed head.     

Changes in head posture and nasopharyngeal airway following surgical correction of mandibular prognathism

It was the aim of the present study to cast light on the role of the mandible in relation to head posture and airway space by evaluating patients before and after surgical correction of mandibular prognathism. The material comprised standardized profile cephalograms of 52 patients with mandibular prognathism. All patients had received orthodontic adjustments prior to mandibular osteotomy. Mean age of the patients was 24.3 years, and 12 males and 40 females participated in the study. The first profile radiograph of each patient was obtained the day before surgery in the natural head (mirror) position. All patients underwent mandibular surgery with a bilateral vertical ramus osteotomy. Approximately one year after surgery, the cephalometric investigation was repeated. Head posture was evaluated by the craniocervical angulation (NSL/CVT and NSL/OPT) and airway space as nasopharyngeal airway size (ad1 and ad2). Changes in posture and airway (ex.2-ex.1) were evaluated by paired t-tests. The results showed a mean increase in head posture of 2.7 degrees (p less than 0.001) and a mean reduction in airway space of 2.3 mm (p less than 0.001).     

Cervical column morphology related to head posture, cranial base angle, and condylar malformation

The present study describes the cervical column as related to head posture, cranial base, and mandibular condylar hypoplasia. Two groups were included in the study. The 'normal' sample comprised 21 subjects, 15 females aged 23-40 years (mean 29.2 years), and six males aged 25-44 years (mean 32.8 years) with neutral occlusion and normal craniofacial morphology. The condylar hypoplasia group comprised the lateral profile radiographs of 11 patients, eight females, and three males, aged 12-38 years (mean 21.6 years). For each individual, a profile radiograph was taken to perform a visual assessment of the morphology of the cervical column. For the normal group only, the profile radiographs were taken in the standardized head posture to measure the head posture and the cranial base angle. Cervical column: Morphological deviations of the cervical column occurred significantly more often in the subjects with condylar hypoplasia compared with the normal group (P < 0.05 and P < 0.01, respectively). The pattern of morphological deviations was significantly more severe in the subjects with condylar hypoplasia compared with the normal group (P < 0.01). Cervical column related to head posture and cranial base: The cervicohorizontal and cranial base angles were statistically larger in females than in males (P < 0.05 and P < 0.01, respectively). No statistically significant age differences were found. Only in females was the cervical lordosis angle (OPT/CVT, P < 0.01), the inclination of the upper cervical spine (OPT/HOR, P < 0.05), and the cranial base angle (n-s-ba, P < 0.05) significantly positively correlated with fusion of the cervical column. These associations were not due to the effect of age.     

The effect of head posture on the pharyngeal airway space (PAS)

The purpose of this study was to investigate the relationship between cranio-cervical inclination and pharyngeal airway space (PAS) by measuring these parameters at different head postures in the same subjects and to obtain a regression equation to correct the values measured. Fifty lateral cephalometric radiographs taken at five different head postures per individual were obtained from ten adults (seven males and three females) aged from 25 to 30 years with nose breathers and Class I occlusion. The changes in cranio-cervical inclination produced by head extension were correlated with changes in the variables describing the PAS. The OPT/NSL (cranio-cervical inclination in the second vertebrae) and C3-Me (distance between the third vertebrae and the Menton) correlated strongly with PAS-TP (the most proximal distance measured between the posterior pharyngeal wall and the tongue base) in the pharyngeal airway space (r = 0.807 and 0.854 respectively). The regression equations were Y = - 27.177+0.39X (Y = PAS-TP, X = OPT/NSL), and Y = -21.105+0.402X (Y = PAS-TP, X = C3-Me), respectively. From these equations we could conclude that an increase of 10 degrees in OPT/NSL or 10 mm in C3-Me increased the pharyngeal airway space (PAS-TP) by about 4 mm.     

Lateral cephalometric analysis of the pharyngeal airway space affected by head posture

To clarify the relationship between head posture and pharyngeal airway space (PAS), the cephalometric parameters at different head postures were examined. Twelve normal Japanese adults (6 males and 6 females) were examined. Lateral cephalometric radiographs were taken at five different head postures in each person. All radiographs were traced, and the measurements were analyzed statistically. PAS was significantly increased by forward inclination of the cervical spine. The most significant correlation was found between the change in CVT/NSL (cranio-cervical inclination in the second and fourth vertebrae) and the change in PAS-TP (the minimal pharyngeal airway space) (r(2)=0.79 in males, r(2)=0.67 in females). The mean CVT/NSL when the head was in the natural (neutral) position was 100.9 degrees in males and 103.5 degrees in females. Linear regression analysis revealed DeltaPAS (mm)=0.37DeltaCVT/NSL (degree) (r(2)=0.79, p<0.0001) in males, and DeltaPAS (mm)=0.33DeltaCVT/NSL (degree) (r(2)=0.51, p<0.0001) in females. The correlation equations were obtained as follows: the corrected PAS (mm)=the actual PAS (mm)+0.37[100.9-the actual NSL/CVT (degree)] in males, and the corrected PAS (mm)=the actual PAS (mm)+0.33[103.5-the actual NSL/CVT (degree)] in females. These results will contribute to obtaining an accurate assessment of the PAS that should be corrected by the cranio-cervical inclination.     

Cervical lordosis in patients who underwent anterior cruciate ligament injury: a cross-sectional study

It has been proposed that intraoral devices can influence cervical posture. Cervical posture might also be influenced by stimuli from the lower limbs, such as injury of the knee. The hypothesis to be tested is that intraoral devices are useful during the rehabilitation of orthopedic patients to accelerate the restoration of postural control. This study evaluates cervical posture on lateral skull radiographs in subjects who suffered anterior cruciate ligament (ACL) injury of the left knee. Twenty adult Caucasian males (mean age 30.6+/-9.2 yrs.) with ACL injury of the left knee were compared with 40 control subjects (mean age 27.9+/-7.2) who did not show any ACL injury. Lateral skull radiographs, made in natural head position (mirror position), were obtained for all subiects. Various postural and morphological variables were individualized on each radiograph. To assess errors due to landmark identification, duplicate measurements were made of 15 radiographs and compared using the Dahlberg formula. The method error from both sources was less than 0.5 degrees for all angular measurements and less than 0.5 mm for all linear measurements. No difference was observed between the two groups in any of the morphological variables of face or in the cervical lordosis angle (CVT/EVT). However, subjects in the study group showed significantly higher craniocervical angulations (SN/OPT, SN/CVT, SN/EVT, pns-ans/OPT, pns-ans/CVT, pns-ans/EVT, GoGn/OPT, GoGn/CVT, GoGn/EVT) compared with the control subjects (p<0.001). The subjects with ACL injury had significant head extension compared with the control subjects.     

Effect of low pull headgear on head position

Objective

To evaluate changes in head position following the use of low pull headgear (LHG) and compare these changes with an untreated control group.

Subjects and methods

The test group comprised pre-treatment and post-treatment lateral cephalograms of 30 males, aged 11 ± 1.5 years, who were receiving LHG therapy for correction of Class II malocclusion. Pre-observation and post-observation lateral cephalograms of 25 untreated male subjects, aged 11 ± 1.6 years, served as controls. The average treatment time for the treatment group was 12 ± 2.02 months and the average observation period for the control group was 11 ± 1.03 months. Four postural variables (NSL/CVT, NSL/OPT, CVT/HOR, OPT/HOR) were measured to evaluate the head position in all subjects pre- and post-observations.

Results

There was no significant difference in all the measurements concerning the head position within each group (p > 0.05). The mean differences of pre- and post-observations of 4 postural variables in the LHG group were 1.43, 0.9, −1.13, and −1.08, while those of the control group were 1.56, −0.32, −0.24, and 0.04, respectively. There was no significant difference between the headgear and control groups for any of the postural variables measured (p = 0.924, 0.338, 0.448, and 0.398, respectively).

Conclusions

Although postural variables showed considerable variability in both groups, head position exhibited no significant changes over a period of 11–12 months either in the control or headgear group.     

Relationships of vertical facial pattern,natural head position and craniocervical posture in young Chinese children

Objective: To investigate relationships of vertical facial patterns, natural head position (NHP), and craniocervical posture in young Chinese children with skeletal Class I relationship.

Methods: Ninety-four patients with skeletal Class I relationship were classified into low, average, and high angle groups according to their mandibular plane angle (NSL/ML). Cephalometric radiographs in NHP were taken. Variables representing vertical and sagittal craniofacial morphology, head posture, and craniocervical posture were measured and compared.

Results: Inclinations of the mandible to the true vertical and cervical column were smallest in the high angle group and largest in the low angle group. Other variables representing head posture and craniocervical posture were largest in the high angle group, smallest in the low angle group. Inclinations of ramus to cervical column were largest in the high angle group and smallest in the low angle group.

Discussion: Subjects with large NSL/ML angles showed extended head and craniocervical posture, while subjects with small NSL/ML angles exhibited flexed head and craniocervical posture.     

Correlations between cephalic posture and facial type in patients suffering from breathing obstructive syndrome.

AIM: In this teleradiographic study, the authors investigate the correlations between facial kind, breathing pattern and cephalic posture. METHODS The research was conducted on a 94 schoolchildren sample. For each patient teleradiographic analysis in-L-L projection and rhinomanometric examination were performed. On the basis of clinical evidences, rhinomanometric results and nasopharyngeal space evaluation, the sample was divided into two groups: the first one included 36 oral breather patients (OB), the second one 58 nasal breathers (NB). RESULTS: The two groups do not differ significantly, with the exception of divergence values, frequently higher in OB than NB. The comparison of craniofacial features and cephalic posture among the groups points out to correlations between large craniocervical angle and skeletal Class II, mandibular retrognathia and increased gonial angle, respectively, not related to breathing patterns. CONCLUSION: According to the authors' results, it can be stated that morphological characteristics classically associated with breathing obstructive syndrome could be induced by altered cephalic posture instead.     

Associations between thoracic kyphosis, head posture, and craniofacial morphology in young adults

The aim of the present study was to investigate associations between thoracic hyper- and hypokyphosis, head posture, and craniofacial morphology in young adults. Using forward bending test and spinal pantographic measurements, 31 subjects, 16 with thoracic hyper- and 15 with hypokyphosis, were selected from a population-based cohort of 430 young adults. Lateral roentgen-cephalograms were taken in natural head posture and craniofacial and postural angular measurements were calculated. Any statistically significant differences between the groups thoracic hyperkyphosis and thoracic hypokyphosis--were analysed using Student's t test. Subjects with thoracic hyperkyphosis had a larger atlantocervical angle (At/ CVT, P < 0.01) than subjects with thoracic hypokyphosis. However, head position (NSL/VER) was similar in both groups, probably owing to the visual perception control of craniovertical relation. There was no statistically significant difference in craniofacial morphologyy between the groups.     

Influence of skeletal class in the morphology of cervical vertebrae: A study using cone beam computed tomography

Objectives:To quantify the prevalence of cervical vertebrae anomalies and to analyze any association between them and skeletal malocclusions or head posture positions in the same study.Materials and Methods:Two hundred forty patients who were attending the Department of Orthodontics of the University of Valencia for orthodontic treatment were selected and divided into three groups: skeletal Class I (control group, 0° <ANB < 4°), Class II (ANB ≥ 4°), and Class III (ANB ≤ 0°) according to ANB Steiner angle. The morphology of the first five cervical vertebrae was analyzed with cone beam computed tomography to identify any anomalies. Intra- and interobserver error methods were calculated.Results:Dehiscence and fusion of one unit (both 23.3%) and partial cleft (11.7%) were the most frequent anomalies, while occipitalization was the least common (3.3%). Dehiscence anomaly was observed when the control group was compared with Classes II and III and partial cleft anomaly when Class I was compared with Class III. Furthermore, NSBa and ss-N-sm/ANB angles were associated with partial cleft anomaly, while NSL/NL angle and extended head posture were associated with fusion anomaly.Conclusions:Fusion, dehiscence, and partial cleft were the most frequent cervical vertebrae anomalies. Dehiscence and partial cleft were found to present statistically significant differences between Class I and Classes II and III. Cervical vertebrae anomalies and head posture were associated with fusion.     

Surgical mandibular advancement and changes in uvuloglossopharyngeal morphology and head posture: a short- and long-term cephalometric study in males

The aim of the present study was to investigate, by means of an extensive cephalometric examination, the alterations which took place in hyoid bone position, head posture, position and morphology of the soft palate, and tongue and sagittal dimensions of the pharyngeal airway after mandibular advancement osteotomy for the correction of mandibular retrognathism. The sample consisted only of adult males who underwent mandibular advancement by bilateral sagittal ramus split osteotomy (BSRO) with rigid fixation. Profile cephalograms were obtained 1-3 days before surgery (20 subjects), and 6 months (20 subjects) and 3 years (19 subjects) after the surgery. Statistical evaluation was performed by paired Student's t-test and Pearson product moment correlation analysis. At the short-term follow-up, hyoid bone and vallecula assumed a more superior (AH perpendicular FH, AH perpendicular ML, AH perpendicular S, V perpendicular FH) and anterior position (AH-C3 Hor, V-C3), which was maintained at the long-term follow-up. The soft palate (NL/PM-U) became more upright at the short-term follow-up. The tongue demonstrated a transient increase in height (H perpendicular VT) and a less upright position (VT/FH) at the long-term observation. In addition, a more upright cervical spine (OPT/HOR, CVT/HOR) was recorded at the long-term follow-up. The pharyngeal airway space at the level of the oropharynx (U-MPW) and the retroglossal space at the base of the tongue (PASmin) showed an increase in the sagittal dimension at the short-term follow-up. Significant widening at the PASmin level was sustained at the long-term follow-up, indicating that mandibular advancement osteotomy could increase airway patency and be a treatment approach for sleep apnoea in selected patients.     

Associations between thoracic kyphosis,head posture,and craniofacial morphology in young adults

The aim of the present study was to investigate associations between thoracic hyper- and hypokyphosis, head posture, and craniofacial morphology in young adults. Using forward bending test and spinal pantographic measurements, 31 subjects, 16 with thoracic hyper- and 15 with hypokyphosis, were selected from a population-based cohort of 430 young adults. Lateral roentgen-cephalograms were taken in natural head posture and craniofacial and postural angular measurements were calculated. Any statistically significant differences between the groups - thoracic hyperkyphosis and thoracic hypokyphosis - were analysed using Student's t test. Subjects with thoracic hyperkyphosis had a larger atlantocervical angle (At/CVT, P &lt; 0.01) than subjects with thoracic hypokyphosis. However, head position (NSL/VER)was similar in both groups, probably owing to the visual perception control of craniovertical relation. There was no statistically significant difference in craniofacial morphology between the groups.     

Effect of bilateral sagittal split ramus osteotomy setback on the soft palate and pharyngeal airway space

To evaluate the effect of bilateral sagittal split ramus osteotomy setback on the morphology of the pharyngeal airway, especially the structures of the soft palate and pharyngeal airway space (PAS), lateral cephalograms obtained from 49 women before treatment and 1 year after surgery were traced and compared. All patients underwent this osteotomy to correct mandibular hyperplasia. The data were corrected with the use of regression equations for the PAS, taking into account head posture. On average, the SNB angle decreased by 3.9 degrees, resulting in an increase of 4.1 degrees in OPT/NSL (head posture, defined as the craniocervical angulation at the uppermost part of the cervical spine). The morphology of the PAS and soft palate changed significantly (p<0.01). The mean reduction in the PAS was 2.6mm retropalatinally and 4.0mm retrolingually. On average, the soft-palate length increased by 3.2mm and the soft-palate angle increased by 4 degrees. These results show that mandibular setback surgery markedly decreases the PAS and changes the morphology of the soft palate.     

Skeletal-versus soft-tissue-based cephalometric analyses: is the correlation reproducible?

Objectives: Dentofacial deformities can be analyzed by skeletal and soft tissue cephalometric analysis (CA). The aim was to evaluate the difference in reproducibility between both methods.

Materials and methods: Lateral cephalograms of 112 patients (65 females and 47 males, 27.7?±?9.0 years) were oriented in natural head position (NHP) and digitized. The distances of skeletal (SNA, SNB, SnPog) and soft tissue (A′, B′ and Pog′) landmarks relative to the respective norm values and the angles between the Nasion Sella line (NSL) and Frankfurt horizontal (FH) to NHP were measured for statistical evaluation and compared with respective data of an adult control group (CG) with class I occlusion and harmonic facial balance.

Results: The mean differences (mm?±?SD) of skeletal and soft tissue landmarks were –2.4?±?4.4 (A), –7.0?±?9.3 (B), –6.3?±?11.2 (Pog), –0.9?±?1.8 (A′), –4.7?±?6.2 (B′), and –6.1?±?7.8 (Pog′), respectively. Pearsons’s correlation (r) between the measurements of SNA/A′, SNB/B′ and SNPog/Pog′ were r?=?.158 (p?=?.092), r?=?.662 (p?<?.001) and r?=?.655 (p?<?.001), respectively. The mean (±SD) angles between NSL and FH to NHP were –9.8°?±?5 and 0.0°?±?3.9, respectively.

Conclusion: Variability of cranial-based measurements could give a possible explanation for the high variation and the low reproducibility of skeletal cephalometric analysis with soft tissue measurements. Soft-tissue cephalometric analysis would probably improve facial analysis and treatment planning.     

Evaluation of the correlation box (Segner) for characterization of the facial skeleton.

The convenience of the so-called harmonious combinations of five basic radiographic cephalometric measurements (Segner), derived from multiple regressions and presented in the form of a correlation box, as a means of diagnosing skeletal malocclusion has been evaluated statistically. The study involved 55 untreated orthodontic patients 7-14 years old with Angle's Class I malocclusion. The correlation box was built stepwise on the basis of four linear regressions computed between five angular measurements (SNA, SNB, NSL/ML, NSL/NL, and NSAr). The regression analyses indicated that the correlation box was not accurate enough. The coefficients of determination for the regressions varied between 0.26 (for NSL/NL) and 0.63 (for SNB). Most part of the variation in NSL/ML, NSL/NL, and NSAr angles remained unexplained. Individual norms indicated by the box for the ANB angle seemed doubtful in many cases. The correlation box seemed to show the statistically most probable associations between measurements used. The combinations may be harmonious but the existence of other harmonious combinations cannot be excluded.