Accuracy of analytic model planning in bimaxillary surgery

Is a Final Splint Necessary in Bimaxillary Orthognathic Surgery?

For bimaxillary orthognathic surgery, a splint is commonly used to achieve the final occlusion and is then maintained through initial skeletal healing. The purpose of this study is to document how often a final splint is used to achieve the planned intraoperative occlusion, and how often is the final splint retained after surgery to maintain the occlusion during the initial skeletal healing phase.The investigators developed a retrospective case series. The study variables were demographic and operative. The outcome variables were the use of a final splint to achieve the desired intraoperative occlusion; the frequency and clinical indication for maintaining the final splint during the 5-weeks of initial skeletal healing; and the occlusion achieved after initial healing (5 weeks) compared to that planned from model surgery. Descriptive statistics were reported.The study sample was composed of 41 consecutive subjects. The mean age at operation was 26.9 ± 11.8 years and 51% of the subjects were male. Twenty-five subjects required segmental maxillary surgery. The final splint was used in 39% of subjects to achieve final occlusion and maintained postoperatively in only 10%. No subjects developed transverse relapse during the initial healing phase (5-weeks). All subjects with planned immediate mid-arch open-bites (n = 8) showed vertical improvement or closure during the initial healing when the splint was not maintained.The use of a final occlusal splint and then maintenance of the splint through initial skeletal healing is not required in the majority of bimaxillary orthognathic surgery cases to achieve the planned occlusion.

Primary Mandibular Deficiency Dentofacial Deformities: Occlusion and Facial Aesthetic Surgical Outcomes

PURPOSE

The purpose of the present study was to document the malocclusion and facial dysmorphology in primary mandibular deficiency (PMD) subjects with chronic obstructive nasal breathing before treatment and the outcomes after bimaxillary orthognathic, genioplasty, and intranasal surgery.

PATIENTS AND METHODS

A retrospective cohort study of PMD subjects undergoing bimaxillary, chin, and intranasal surgery was implemented. The predictor variables were grouped into demographic, anatomic, operative, and longitudinal categories. The primary outcome variables were the initial postoperative occlusion achieved at 5 weeks postoperatively (T₂) and that maintained long-term more than 2 years after surgery (T₄). Six occlusion parameters were assessed: overjet, overbite, coincidence of dental midlines, Angle classification, molar vertical, and transverse positions. A second outcome variable was the facial esthetic results. Photographs were analyzed to document 7 facial contour characteristics.

RESULTS

Forty subjects met the inclusion criteria. Their age at surgery averaged 32 years (range 13 to 63). The study included 25 females (63%). The findings confirmed that the occlusion after initial surgical healing (T₂) met the objectives for all parameters in 39 of the 40 patients (98%). Most patients (35 of 40; 88%) achieved and maintained a favorable occlusion for each parameter in the long-term (mean 5 years, 3 months). Subjects requiring counterclockwise rotation of the maxillomandibular complex were more likely to a have recurrent anterior open bite in the long-term. Facial contour deformities on presentation included weak chin (80%), deep labiomental fold (90%), everted lower lip (100%), short neck-to-chin length (88%), obtuse neck-to-chin angle (85%), weak mandible angles (93%), and "bunching" of the neck soft tissues (85%). Before surgery, 88% of the subjects exhibited a minimum of 5 of the 7 facial deformities. Correction of all 7 facial deformities was confirmed in 86% of the subjects in the long-term.

CONCLUSIONS

Most PMD subjects achieved and maintained a corrected occlusion in the long-term. In the untreated subjects, a "facial type" was identified. Orthognathic surgery proved effective in correcting the associated facial dysmorphology in most patients.

The Impact of the Use of Kinesio Taping Method on the Reduction of Swelling in Patients After Orthognathic Surgery: A Pilot Study

BACKGROUND Orthognathic surgery (OGS) is associated with extensive surgical intervention within the soft and hard tissues of the facial region of the skull leading to inflammatory reactions. The presence of postoperative swelling indicates the accumulation of exudate or transudate; both these fluids occur in surgery. Massive swelling is a significant problem, because the tension of tissues intensifies pain sensations. The aim of the study was to evaluate the effectiveness of the kinesio taping method (KT) in patients after orthognathic surgery in the area of the facial skull in terms of eliminating postoperative swelling. MATERIAL AND METHODS The study of the impact of kinesiology tape applied after orthognathic surgery to the craniofacial area on the elimination of swelling was performed in sixteen patients who suffered from this complication after bilateral sagittal split osteotomy. RESULTS The swelling was shown to be reduced after KT; within the same study the differences were statistically significant between the left and right sides and for the same side (p<0.05). The application of the lymphatic kinesio taping method led to the reduction of tension in the affected area and restoration of proper lymphatic circulation in the region covered by swelling. This allows for the improvement of the blood and lymph microcirculation and activation of self-healing processes. CONCLUSIONS The analysis of the impact of the practical use of the lymphatic KT on complications after orthognathic surgery revealed that it had a beneficial effect on the reduction of swelling. The use of the KT method seems promising because it is simple to carry out, not traumatic, economical and rarely causes undesirable allergies.

Primary Maxillary Deficiency Dentofacial Deformities: Occlusion and Facial Esthetic Surgical Outcomes

PURPOSE

The purpose of this study was to document the malocclusion and facial dysmorphology in patients with primary maxillary deficiency (PMD) and chronic obstructive nasal breathing before treatment and the outcomes after bimaxillary orthognathic, genioplasty, and intranasal surgery.

MATERIALS AND METHODS

A retrospective cohort study of patients with PMD undergoing bimaxillary orthognathic, chin, and intranasal surgery was implemented. The predictor variables were grouped into demographic, anatomic, operative, and longitudinal follow-up categories. The primary outcome variables were the initial postoperative occlusion achieved (T₂; 5 weeks postoperatively) and that maintained long-term (T₃ or T₄; >2 years after surgery). Six occlusion parameters were assessed: overjet, overbite, coincidence of dental midlines, Angle classification, and molar vertical and transverse positions. A second outcome variable was facial esthetic results. Photographs were analyzed to document 7 facial contour characteristics.

RESULTS

Sixty-six patients met the inclusion criteria. Age at operation averaged 22 years (15 to 55 yr). The study included 18 women (27%). Most patients (57 of 66; 86%) achieved and maintained a favorable occlusion for each parameter studied long-term (mean, 5 yr). The need for a 3-segment Le Fort I was strongly associated with long-term posterior malocclusion. Facial dysmorphology before surgery included the appearance of a prominent chin (56%), flat labiomental fold (61%), prominent lower lip (88%), prominent nose (77%), sunken midface (100%), flat cheekbones (82%), and recessed upper lip (73%). Before surgery, 82% of patients exhibited at least 5 of the 7 key facial contour deformities. Correction of all 7 facial contour deformities was confirmed in 92% of patients in the long-term. In 8% of patients, an overly prominent-appearing chin persisted.

CONCLUSION

Using orthognathic techniques, most patients with PMD achieved and maintained a corrected occlusion long-term. In unoperated patients, a "facial esthetic type" was identified. Bimaxillary orthognathic and chin surgery proved effective in correcting associated facial dysmorphology in most patients.

Long-Face Dentofacial Deformities: Occlusion and Facial Esthetic Surgical Outcomes

PURPOSE

The purpose of this study was to document malocclusion and facial dysmorphology in a series of patients with long face (LF) and chronic obstructive nasal breathing before treatment and the outcomes after bimaxillary orthognathic, osseous genioplasty, and intranasal surgery.

MATERIALS AND METHODS

A retrospective cohort study of patients with LF undergoing bimaxillary, chin, and intranasal (septoplasty and inferior turbinate reduction) surgery was implemented. Predictor variables were grouped into demographic, anatomic, operative, and longitudinal follow-up categories. Primary outcome variables were the initial postoperative occlusion achieved (T₂; 5 weeks after surgery) and the occulsion maintained long-term (>2 years after surgery). Six key occlusion parameters were assessed: overjet, overbite, coincidence of dental midlines, canine Angle classification, and molar vertical and transverse positions. The second outcome variable was the facial esthetic results. Photographs in 6 views were analyzed to document 7 facial contour characteristics.

RESULTS

Seventy-eight patients met the inclusion criteria. Average age at surgery was 24 years (range, 13 to 54 yr). The study included 53 female patients (68%). Findings confirmed that occlusion after initial surgical healing (T₂) met the objectives for all parameters in 97% of patients (76 of 78). Most (68 of 78; 87%) maintained a favorable anterior and posterior occlusion for each parameter studied long-term (mean, 5 years 5 months). Facial contour deformities at presentation included prominent nose (63%), flat cheekbones (96%), flat midface (96%), weak chin (91%), obtuse neck-to-chin angle (56%), wide lip separation (95%), and excess maxillary dental show (99%). Correction of all pretreatment facial contour deformities was confirmed in 92% of patients after surgery. Long face patients with higher preoperative body mass index levels were more likely to have residual facial dysmorphology after surgery (P = .0009).

CONCLUSION

Using orthognathic surgery techniques, patients with LF dentofacial deformity achieved the planned occlusion and most maintained the corrected occlusion long-term. In unoperated patients with LF, a "facial esthetic type" was identified. Orthognathic surgery proved effective in correcting associated facial dysmorphology in most patients.

The accuracy of maxillary positioning using digital model planning and 3D printed wafers in bimaxillary orthognathic surgery

OBJECTIVE

Orthognathic wafers may be made using digital model movements and CAD-CAM technology. This paper analysed the accuracy of maxillary movements using this new process.

DESIGN

Retrospective study of pre and post-operative cephalograms.

PARTICIPANTS

Thirty consecutive orthognathic patients undergoing bimaxillary osteotomies in a UK hospital.

METHODS

Jaw movements were planned using cephalometric and Orthoanalyzer™ software. The resultant intermediate and final wafer occlusal relationships were used for wafer fabrication by 3D printing of the inter-occlusal space. Pre- and post-operative lateral cephalograms were compared in terms of maxillary antero-posterior and vertical movements. Statistical analyses including the paired t-test, two-sample t-test and Fisher's exact test.

RESULTS

Wide individual variation was observed between the planned and actual movements. Thirteen cases (43%) had a 2 mm discrepancy in at least one variable. Statistically significant differences between the planned and actual maxillary vertical movements were observed for the molar (U6y: p < 0.0001) and anterior maxillary (Ay: p < 0.01) differences. Analysis of a subgroup with primarily impaction movements demonstrated a statistically significant bias towards excessive maxillary advancement (U1x: p < 0.01) and incisor impaction (U1y: p < 0.01) in this group.

CONCLUSIONS

This new digital surgical wafer technique achieves a similar level of accuracy to the conventional facebow and model surgery process.

"Silent" Sleep Apnea in Dentofacial Deformities and Prevalence of Daytime Sleepiness After Orthognathic and Intranasal Surgery

PURPOSE

The purposes of this study were to determine the occurrence of undiagnosed "silent" obstructive sleep apnea (OSA) in dentofacial deformity (DFD) patients at initial surgical presentation and to report on the level of daytime sleepiness in DFD patients with OSA and chronic obstructive nasal breathing (CONB) after undergoing bimaxillary, chin, and intranasal surgery.

MATERIALS AND METHODS

A retrospective cohort study of patients with a bimaxillary DFD and CONB was implemented. Patients were divided into those with no OSA (group I) and those with OSA (group II). Group II was further subdivided into patients referred with polysomnogram (PSG)-confirmed OSA (group IIa) and those with a diagnosis of OSA only after surgical consultation, airway evaluation, and a positive PSG (group IIb). Group II patients were analyzed at a minimum of 1 year after surgery (range, 1 to 10 years) for daytime sleepiness with the Epworth Sleepiness Scale. Patients with postoperative excessive daytime sleepiness were assessed for risk factors and continued need for OSA treatment. Patients in group II were studied to determine which DFD patterns were most associated with OSA. We compared the prevalence of OSA between our study population and the general population.

RESULTS

Two hundred sixty-two patients met the inclusion criteria. Of these, 23% (60 of 262) had PSG-confirmed OSA (group II). This rate was much higher than that found in the general population. Of the patients, 7% (19 of 262) were known to have OSA at initial surgical consultation (group IIa). An additional 16% (41 of 262) were later confirmed by PSG to have OSA (group IIb). Patients with primary mandibular deficiency and short face DFDs were most likely to have OSA (P < .001 and P = .001, respectively). In group II, 91% (55 of 60) rated their daytime sleepiness as "not sleepy" at a minimum of 1 year after surgery. A significant association was found between group II patients with postoperative excessive daytime sleepiness ("sleepy" or "very sleepy") and a preoperative body mass index category of overweight (P = .026).

CONCLUSIONS

Our study found silent OSA to be frequent in the DFD population. The prevalence of OSA in DFD patients exceeded that estimated in the general population, with retrusive jaw patterns most affected. In DFD patients also presenting with OSA and CONB, we confirmed low levels of daytime sleepiness long-term after simultaneous bimaxillary orthognathic, chin, and intranasal surgery.

Current Status of Surgical Planning for Orthognathic Surgery: Traditional Methods versus 3D Surgical Planning

Background:

Orthognathic surgery has traditionally been performed using stone model surgery. This involves translating desired clinical movements of the maxilla and mandible into stone models that are then cut and repositioned into class I occlusion from which a splint is generated. Model surgery is an accurate and reproducible method of surgical correction of the dentofacial skeleton in cleft and noncleft patients, albeit considerably time-consuming. With the advent of computed tomography scanning, 3D imaging and virtual surgical planning (VSP) have gained a foothold in orthognathic surgery with VSP rapidly replacing traditional model surgery in many parts of the country and the world. What has yet to be determined is whether the application and feasibility of virtual model surgery is at a point where it will eliminate the need for traditional model surgery in both the private and academic setting.

Methods:

Traditional model surgery was compared with VSP splint fabrication to determine the feasibility of use and accuracy of application in orthognathic surgery within our institution.

Results:

VSP was found to generate acrylic splints of equal quality to model surgery splints in a fraction of the time. Drawbacks of VSP splint fabrication are the increased cost of production and certain limitations as it relates to complex craniofacial patients.

Conclusions:

It is our opinion that virtual model surgery will displace and replace traditional model surgery as it will become cost and time effective in both the private and academic setting for practitioners providing orthognathic surgical care in cleft and noncleft patients.