Three-dimensional regional displacement after surgical-orthodontic correction of Class III malocclusion.

OBJECTIVES: To investigate how displacements of maxillo-mandibular structures are associated with each other at splint removal and 1 year post-surgery following 1-jaw and 2-jaw surgeries for correction of Class III malocclusion. SETTING AND SAMPLE POPULATION: Fifty patients who underwent surgical correction with maxillary advancement only (n = 25) or combined with mandibular setback (n = 25) were prospectively enrolled in this study. METHODS: Cone-beam computed tomographies were taken pre-surgery, at splint removal and at 1 year post-surgery. Three-dimensional cranial base superimpositions and shape correspondence were used to measure the outcomes from pre-surgery to splint removal (surgical changes) and splint removal to 1 year post-surgery (post-surgical adaptations). Pearson's correlation coefficients were used to evaluate the association between the regional displacements. RESULTS: Both surgery groups presented mandibular clockwise rotation with surgery and post-surgical adaptive counterclockwise rotation. In patients treated with maxillary advancement only, the surgical changes of the maxilla were significantly correlated with chin changes. The amount and direction of chin autorotation were significantly correlated with right and left ramus autorotation. Right and left condylar displacements were significantly correlated. One year post-surgery, adaptive displacements and bone remodeling of both rami were correlated with the chin and condylar changes. For the 2-jaw group, the few correlations between the positional and remodeling changes in the anatomic regions of interest observed due to the surgery were different than those observed after post-surgical adaptations, suggesting that these changes occurred independently. CONCLUSION: Our results indicate that surgical displacements and post-surgical adaptations are often correlated in one-jaw surgery and are, in general, independent in two-jaw surgery.

Sensory retraining: burden in daily life related to altered sensation after orthognathic surgery, a randomized clinical trial.

OBJECTIVE: Assess the long-term effect of sensory retraining exercises, age, gender, type of surgery, and pre-surgical psychological distress on patients' perception of the interference related to altered sensation 2 years after orthognathic surgery. SETTING AND SAMPLE POPULATION: A total of 186 subjects with a developmental dentofacial disharmony were enrolled in a multicenter randomized clinical trial: one center was a community-based practice and the other a university-based center. METHODS AND MATERIALS: Subjects were randomly allocated to two groups: standard of care mouth opening exercises after BSSO or a progressive series of sensory retraining facial exercises in addition to the opening exercises. At 1, 3, 6, 12, and 24 months after surgery, subjects scored unusual feelings on the face, numbness, and loss of lip sensitivity from 'no problem (1)' to 'serious problem (7)'. A marginal proportional odds model was fit for each of the ordinal outcomes. RESULTS: Up to 2 years after surgery, the opening exercise only group had a higher likelihood of reporting interference in daily activities related to numbness and loss of lip sensitivity than the sensory retraining exercise group. The difference between the two groups was relatively constant. Older subjects and those with elevated psychological distress before surgery reported higher burdens related to unusual facial feelings, numbness, and loss of lip sensitivity (p < 0.02). CONCLUSION: The positive effect of sensory retraining facial exercises observed after surgery is maintained over time. Clinicians should consider the patient's age and psychological well-being prior to providing pre-surgical counseling regarding the impact on daily life of persistent altered sensation following a mandibular osteotomy.

Facial altered sensation and sensory impairment after orthognathic surgery.

The aim of this study was to determine whether impairment of sensory functions after trigeminal nerve injury differs in severity among patients who report qualitatively different altered sensations. Data were obtained from 184 patients. Before and at 1, 3 and 6 months after orthognathic surgery, patients were grouped as having no altered sensation, negative sensations only (hypoaesthetic), mixed sensations (negative+active), or active sensations only (paraesthetic or dysaesthetic). Bias-free estimates of contact detection and two-point discrimination were obtained to assess, via ANOVA, whether patients in the four groups exhibited different levels of sensory impairment. Impairment in contact detection and two-point discrimination was found to differ significantly among the groups at 6 months but not at 1 month. At 6 months, patients who reported negative sensations only exhibited the greatest impairment, on average, in contact detection; in contrast, patients who reported mixed sensations exhibited the greatest impairment in two-point discrimination. The least residual impairment at 6 months was observed in patients who reported no altered sensation. It is recommended that clinical judgments regarding nerve injury-associated sensory dysfunction should not be based on threshold testing results without consideration of patients' subjective reports of altered sensation.

Orbital apex disorders: a case series.

Orbital apex syndrome is an uncommon disorder characterized by ophthalmoplegia, proptosis, ptosis, hypoesthesia of the forehead, and vision loss. It may be classified as part of a group of orbital apex disorders that includes superior orbital fissure syndrome and cavernous sinus syndrome. Superior orbital fissure syndrome presents similarly to orbital apex syndrome without optic nerve impairment. Cavernous sinus syndrome includes hypoesthesia of the cheek and lower eyelid in addition to the signs seen in orbital apex syndrome. While historically described separately, these three disorders share similar causes, diagnostic course, and management strategies. The purpose of this study was to report three cases of orbital apex disorders treated recently and to review the literature related to these conditions. Inflammatory and vascular disorders, neoplasm, infection, and trauma are potential causes of orbital apex disorders. Management is directed at the causative process. The cases described represent a rare but important group of conditions seen by the maxillofacial surgeon. A review of the clinical presentation, etiology, and management of these conditions may prompt timely recognition and treatment.

Postoperative nausea and vomiting following orthognathic surgery.

The purpose of this study was to assess the incidence and risk factors associated with postoperative nausea (PON) and vomiting (POV) after orthognathic surgery. A review of the clinical records of consecutively enrolled subjects (2008-2012) at a single academic institution was conducted between 9/2013 and 3/2014. Data on the occurrence of PON and POV and potential patient-related, intraoperative, and postoperative explanatory factors were extracted from the medical records. Logistic models were used for the presence/absence of postoperative nausea and vomiting separately. Data from 204 subjects were analyzed: 63% were female, 72% Caucasian, and the median age was 19 years. Thirty-three percent had a mandibular osteotomy alone, 27% a maxillary osteotomy alone, and 40% had bimaxillary osteotomies. Sixty-seven percent experienced PON and 27% experienced POV. The most important risk factors for PON in this series were female gender, increased intravenous fluids, and the use of nitrous oxide, and for POV were race, additional procedures, and morphine administration. The incidence of PON and POV following orthognathic surgery in the current cohort of patients, after the introduction of the updated 2007 consensus guidelines for the management of postoperative nausea and vomiting, has not decreased substantially from that reported in 2003-2004.

A controlled comparative investigation of psychological treatments for chronic sleep-onset insomnia.

A sample of physician-referred chronic insomniacs was randomly allocated to either progressive relaxation, stimulus control, paradoxical intention, placebo or no treatment conditions. Treatment process and outcome were investigated in terms of mean and standard deviation (night to night variability) measures of sleep pattern and sleep quality. Only active treatments were associated with significant improvement, but the nature of treatment gains varied. In particular, stimulus control improved sleep pattern, whereas relaxation affected perception of sleep quality. All improvements were maintained at 17 month follow-up. Results are discussed with reference to previous research and guidelines are given for clinical practice.

Effects of trauma to the mandibular nerve on human perioral directional sensitivity.

The capacity of 4 patients who had previously experienced trauma to their mandibular nerves to distinguish opposing directions of tactile motion over the distribution of the mental nerve was compared to that of 8 neurologically normal adults. Brushing stimuli were delivered to the perioral region and were precisely controlled for their velocity, the length of skin traversed, the width of skin contacted, and the orientation and direction of motion. A temporal, 2-alternative, forced choice method was used to obtain estimates of directional sensitivity, d'. It was discovered that impairment in cutaneous directional sensitivity could be readily detected within areas of hypaesthesia. Although directional sensitivity was found to increase linearly with the length of skin traversed for both the patients and the neurologically normal adults, the slope and the x-intercept of the linear relationship differed between the two groups. The difference in the slope suggests that direction discrimination within the hypaesthetic areas is relatively insensitive to changes in the length of skin traversed. The difference in the x-intercept suggests that a greater length of skin must be traversed before any information about direction is made available at the hypaesthetic sites. The dependency of the capacity of neurologically normal and impaired individuals to process information about direction of tactile motion on the length of skin traversed and the velocity of stimulation suggests that a high degree of stimulus control is required for the detection and quantification of subtle neurosensory deficits.

Orthodontic-surgical interaction in the management of cleft lip and palate.

The orthodontist's role in the cleft palate team requires close collaboration with the surgeons and other team members. The rationale of timing and sequencing of orthodontic treatment have been discussed in the various time frames, which for convenience have been considered as follows: (1) neonatal or infant maxillary orthopedics; (2) orthodontic considerations in the primary dentition; (3) mixed dentition orthodontics to include presurgical recommendations before an alveolar bone graft and its rationale for use in selected patients; and (4) orthognathic surgery combining an orthodontic and surgical approach to the correction of dental and skeletal components of malocclusion in the permanent dentition. Speech considerations and the communicative skills of the patient with a cleft are important aspects in planning orthognathic surgery for this group of patients. Also, subsequent nose and lip revisions for cosmetic improvement must not be underestimated in the enhancement of the final result following correction of the skeletal and dental discrepancies. Provided the timing and sequencing of appropriate treatment modalities are planned in a closely coordinated, problem-oriented approach by the team members, cleft patients should currently have optimal functional and esthetic results.

Orthognathic surgery: a significant contribution to facial and dental esthetics.

Esthetic dentistry was once a specialty of the family dentist and the orthodontist. Today it is a field for the prosthodontist, periodontist, oral and maxillofacial surgeon, and others. When jawbones are malpositioned, unesthetic facial contours can result, and dental compensations occur that can be additionally unattractive. Orthodontic attempts to correct malocclusion or other disharmonies of the dentition in affected individuals without surgical intervention can cause tooth instability and result in less than satisfactory cosmetic results. The treatment of orthognathic surgeons is especially well suited for full-face esthetic appearance--the picture the patient views each day in the mirror.

Multidisciplinary management of Crouzon syndrome.

The comprehensive management of Crouzon syndrome in a 14-year-old girl has been presented. Because of the complexity of the facial and associated problems, a multidisciplinary approach is necessary to provide maximum functional and esthetic results; however, with such a cooperative interdisciplinary effort, the improvement and benefits derived for these patients are rewarding to all concerned.

Orbital emphysema causing vision loss after a dental extraction.

The use of high-speed air-cooled rotary cutting instruments is common in dental practices. When used near open wounds, the forced air can lead to subcutaneous emphysema and involvement of vital structures. This case highlights the unfortunate episode of orbital emphysema with optic nerve damage after a pneumatically cooled drill was used in the removal of a mandibular second molar.

Long-term stability of surgical open-bite correction by Le Fort I osteotomy.

Skeletal changes greater than those observed in untreated adults have been noted beyond 1 year post-surgery in adult patients who had surgical correction of a long face deformity. The stability of skeletal landmarks and dental relationships from 1 to >3 years post-surgery was examined in 28 patients who had undergone surgery of the maxilla only, and in 26 patients who had undergone 2-jaw surgery to correct >2 mm anterior open bite. Although the average changes in almost all landmark positions and skeletal dimensions were less than 1 mm, point B moved down >2 mm and face height increased >2 mm in one-third of the maxilla-only group and in 40% of the 2-jaw group (>4 mm in 10% and 22% respectively). Overbite decreased 2-4 mm in only 7% of the maxilla-only and 12% of the 2 groups, with no changes >4 mm, because in three-fourths of the patients with an increase in anterior face height, further eruption of the incisors maintained the overbite relationship. In the maxilla-only group, mandibular length (Co-Pg) showed >2 mm long-term change in 45% of the patients, two-thirds of whom showed an increase rather than a decrease in length. In the 2-jaw group, no patients showed a decrease in Co-Pg length and one-third had an increase. For both groups, changes in overjet were smaller and less frequent than changes in mandibular length.

Are bioresorbable polylactate devices comparable to titanium devices for stabilizing Le Fort I advancement?

The purpose of this study was to evaluate whether skeletal and dental outcomes following Le Fort I surgery differed when stabilization was performed with polylactate bioresorbable devices or titanium devices. Fifty-seven patients with preoperative records and at least 1 year postoperative records were identified and grouped according to the stabilization method. All cephalometric X-rays were traced and digitized by a single operator. Analysis of covariance was used to compare the postsurgical change between the two stabilization methods. Twenty-seven patients received bioresorbable devices (group R), while 30 received titanium devices (group M). There were no statistically significant differences between the two groups with respect to gender, race/ethnicity, age, or dental and skeletal movements during surgery. Subtle postsurgical differences were noted, but were not statistically significant. Stabilization of Le Fort I advancement with polylactate bioresorbable and titanium devices produced similar clinical outcomes at 1 year following surgery.

One-year assessment of surgical outcomes in Class III patients using cone beam computed tomography.

The purpose of this study was to apply a novel method to evaluate surgical outcomes at 1 year after orthognathic surgery for Class III patients undergoing two different surgical protocols. Fifty patients divided equally into two groups (maxillary advancement only and combined with mandibular setback) had cone beam computed tomography (CBCT) scans taken pre-surgery, at splint removal, and at 1-year post-surgery. An automatic cranial base superimposition method was used to register, and shape correspondence was applied to assess, the overall changes between pre-surgery and splint removal (surgical changes) and between splint removal and 1-year post-surgery at the end of orthodontic treatment (post-surgical adaptations). Post-surgical maxillary adaptations were exactly the same for both groups, with 52% of the patients having changes >2mm. Approximately half of the post-surgical changes in the maxilla for both groups were vertical. The two-jaw group showed significantly greater surgical and post-surgical changes in the ramus, chin, and most of the condylar surfaces (P<0.05). Post-surgical adaptation on the anterior part of the chin was also more significant in the two-jaw group (P<0.05). Regardless of the type of surgery, marked post-surgical adaptations were observed in the regions evaluated, which explain the adequate maxillary-mandibular relationship at 1-year post-surgery on average, with individual variability.

Biodegradable fixation for craniomaxillofacial surgery: a 10-year experience involving 761 operations and 745 patients.

Patient acceptance, safety, and efficacy of poly-l/dl-lactic acid (PLLDL) bone plates and screws in craniomaxillofacial surgery are reported in this article. Included in the sample are 745 patients who underwent 761 separate operations, including more than 1400 surgical procedures (orthognathic surgery (685), bone graft reconstruction (37), trauma (191) and transcranial surgery (20)). The success (no breakage or inflammation requiring additional operating room treatment) was 94%. Failure occurred because of breakage (14) or exuberant inflammation (31). All breakage occurred at mandibular sites and the majority of inflammatory failure occurred in the maxilla or orbit (29), with only two in the mandible. Failures were evenly distributed between the two major vendors. PLLDL 70/30 bone plates and screws may be used successfully in a variety of craniomaxillofacial surgical applications. The advantages include the gradual transference of physiological forces to the healing bone, the reduced need for a second operation to remove the material and its potential to serve as a vehicle to deliver bone-healing proteins to fracture/osteotomy sites. Bone healing was noted at all sites, even where exuberant inflammation required a second surgical intervention.

Soft tissue response to mandibular advancement using 3D CBCT scanning.

This prospective longitudinal study assessed the 3D soft tissue changes following mandibular advancement surgery. Cranial base registration was performed for superimposition of virtual models built from cone beam computed tomography (CBCT) volumes. Displacements at the soft and hard tissue chin (n = 20), lower incisors and lower lip (n = 21) were computed for presurgery to splint removal (4-6-week surgical outcome), presurgery to 1 year postsurgery (1-year surgical outcome), and splint removal to 1 year postsurgery (postsurgical adaptation). Qualitative evaluations of color maps illustrated the surgical changes and postsurgical adaptations, but only the lower lip showed statistically significant postsurgical adaptations. Soft and hard tissue chin changes were significantly correlated for each of the intervals evaluated: presurgery to splint removal (r = 0.92), presurgery to 1 year postsurgery (r = 0.86), and splint removal to 1 year postsurgery (r = 0.77). A statistically significant correlation between lower incisor and lower lip was found only between presurgery and 1 year postsurgery (r = 0.55). At 1 year after surgery, 31% of the lower lip changes were explained by changes in the lower incisor position while 73% of the soft tissue chin changes were explained by the hard chin. This study suggests that 3D soft tissue response to mandibular advancement surgery is markedly variable.

Long-term stability of adolescent versus adult surgery for treatment of mandibular deficiency.

In mandibular deficient patients, mandibular growth is not expected after the adolescent growth spurt, so mandibular advancement surgery is often carried out at 13 years. To test if the long-term stability for younger patients is similar to that for adult patients, the authors compared cephalometric changes from 1-year postsurgery (when changes due to the surgery should be completed) to 5-year follow up. 32 patients who had early mandibular advancement with or without simultaneous maxillary surgery (aged up to 16 for girls and 18 for boys), and 52 patients with similar surgery at older ages were studied. Beyond 1-year postsurgery, the younger patients showed significantly greater change in the horizontal and vertical position of points B and pogonion, the horizontal (but not vertical) position of gonion, and mandibular plane angle. 50% of younger patients had 2-4mm backward movement of Pg and another 25% had >4mm. 15% of older patients had 2-4mm change and none had >4mm. Long-term changes in younger patients who had two-jaw surgery were greater than for mandibular advancement only. Changes in younger groups were greater than for adult groups. Satisfaction with treatment and perception of problems were similar for both groups.

Superimposition of 3D cone-beam CT models of orthognathic surgery patients.

OBJECTIVES: To evaluate the registration of 3D models from cone-beam CT (CBCT) images taken before and after orthognathic surgery for the assessment of mandibular anatomy and position. METHODS: CBCT scans were taken before and after orthognathic surgery for ten patients with various malocclusions undergoing maxillary surgery only. 3D models were constructed from the CBCT images utilizing semi-automatic segmentation and manual editing. The cranial base was used to register 3D models of pre- and post-surgery scans (1 week). After registration, a novel tool allowed the visual and quantitative assessment of post-operative changes via 2D overlays of superimposed models and 3D coloured displacement maps. RESULTS: 3D changes in mandibular rami position after surgical procedures were clearly illustrated by the 3D colour-coded maps. The average displacement of all surfaces was 0.77 mm (SD=0.17 mm), at the posterior border 0.78 mm (SD=0.25 mm), and at the condyle 0.70 mm (SD=0.07 mm). These displacements were close to the image spatial resolution of 0.60 mm. The average interobserver differences were negligible. The range of the interobserver errors for the average of all mandibular rami surface distances was 0.02 mm (SD=0.01 mm). CONCLUSION: Our results suggest this method provides a valid and reproducible assessment of craniofacial structures for patients undergoing orthognathic surgery. This technique may be used to identify different patterns of ramus and condylar remodelling following orthognathic surgery.

Intraoperative complications of sagittal osteotomy of the mandibular ramus: incidence and management.

The intraoperative complications occurring with 256 sagittal osteotomies operated by two different osteotomy designs are presented. Intraoperative complications occurred in 8.2% of the cases. Aside from operator experience and skill, complications appeared to be related to the osteotomy design and attention to detail during the operation.