Cephalometric and three-dimensional assessment of the posterior airway space and imaging software reliability analysis before and after orthognathic surgery.

PURPOSE: This study aimed to compare the reliability of three different imaging software programs for measuring the PAS and concurrently to investigate the morphological changes in oropharyngeal structures in mandibular prognathic patients before and after orthognathic surgery by using 2D and 3D analyzing technique. MATERIAL AND METHODS: The study consists of 11 randomly chosen patients (8 females and 3 males) who underwent maxillomandibular treatment for correction of Class III anteroposterior mandibular prognathism at the University Hospital in Zurich. A set of standardized LCR and CBCT-scans were obtained from each subject preoperatively (T0), 3 months after surgery (T1) and 3 months to 2 years postoperatively (T2). Morphological changes in the posterior airway space (PAS) were evaluated longitudinally by two different observers with three different imaging software programs (OsiriX(®) 64-bit, Switzerland; Mimics(®), Belgium; BrainLab(®), Germany) and manually by analyzing cephalometric X-rays. RESULTS: A significant increase in the upper airway dimensions before and after surgery occurred in all measured cases. All other cephalometric distances showed no statistically significant alterations. Measuring the volume of the PAS showed no significant changes in all cases. All three software programs showed similar outputs in both cephalometric analysis and 3D measuring technique. CONCLUSION: A 3D design of the posterior airway seems to be far more reliable and precise phrasing of a statement of postoperative gradients than conventional radiography and is additionally higher compared to the corresponding manual method. In case of Class III mandibular prognathism treatment with bilateral split osteotomy of the mandible and simultaneous maxillary advancement, the negative effects of PAS volume decrease may be reduced and might prevent a developing OSAS.

Assessing aesthetic outcomes after trigonocephaly correction.

PURPOSE: This study analysed the aesthetic outcome assessments after trigonocephaly correction using different assessor groups. METHODS: Twenty-four patients (9 males, 15 females) with a surgical age between 8 and 10 months were included. Standardised photographs showing different facial views of the patients between ages 3 and 6 years were evaluated in terms of aesthetics by three study groups: surgeons, medical students, and lay persons. Each photograph was scored as follows: 1 (normal), 2 (acceptable, no need for revision), or 3 (unacceptable, needs revision). RESULTS: The mean surgical age was 9.1 ±0.4 months. Based on the en-face images, the mean scores assigned by the surgeon, student, and lay groups were 1.4 ±0.49, 1.25 ±0.44, and 1.13 ±0.34, respectively. Based on the patients' profiles, the mean scores assigned by the surgeon, student, and lay groups were 1.37 ±0.49, 1.16 ±0.37, and 1.09 ±0.29, respectively. The scores of the hemi-profile evaluation were 1.14 ±0.35, 1.07 ±0.26, and 1.09 ±0.31, respectively. The scores of the frontal region were 1.47 ±0.54, 1.33 ±0.49, and 1.39 ±0.49, respectively. Within the orbital area, the surgeon, student, and lay groups assigned mean scores of 1.53 ±0.56, 1.29 ±0.46, and 1.15 ±0.36, respectively. The midface analysis showed mean scores of 1.8 ±0.66, 1.63 ±0.52, and 1.46 ±0.5, respectively. In all areas, there were significant differences (P < 0.05) among the assessor groups. CONCLUSION: The expectations regarding aesthetic outcome differ considerably between experts and non-experts. The need for correction did not concern the reshaped bone but rather the soft tissue epicanthal area.

Validity of the 3D VECTRA photogrammetric surface imaging system for cranio-maxillofacial anthropometric measurements.

PURPOSE: The use of three-dimensional (3D) photography for anthropometric measurements is of increasing interest, especially in the cranio-maxillofacial field. Before standard implementation, accurate determination of the precision and accuracy of each system is mandatory. METHODS: A mannequin head was labelled with 52 landmarks, and 28 three-dimensional images were taken using a commercially available five-pod 3D photosystem (3D VECTRA; Canfield, Fairfield, NJ) in different head positions. Distances between the landmarks were measured manually using a conventional calliper and compared with the digitally calculated distances acquired from labelling by two independent observers. The experimental set-up accounted for clinical circumstances by varying the positioning (vertical, horizontal, sagittal) of the phantom. RESULTS: In the entire calliper measurement data set (n = 410), a significant difference (p = 0.02) between the directly measured and corresponding virtually calculated distances was found. The mean aberration between both modalities covering all data was 7.96 mm. No differences (p = 0.94) between the two groups were found using a cut-off of 10 % (leaving n = 369 distances) due to considerable errors in direct measurements and the necessary manual data translation. The mean diversity of both measurement modalities after cut-off was 1.33 mm (maximum, 6.70 mm). Inter-observer analysis of all 1,326 distances showed no difference (p = 0.99; maximal difference, 0.58 mm) in the digital measurements. CONCLUSION: The precision and accuracy of this five-pod 3D photosystem suggests its suitability for clinical applications, particularly anthropometric studies. Three-hundred-and-sixty degree surface-contour mapping of the craniofacial region within milliseconds is particularly useful in paediatric patients. Proper patient positioning is essential for high-quality imaging.

Cranial vault growth in multiple-suture nonsyndromic and syndromic craniosynostosis: a postoperative long-term anthropometric follow-up.

Long-term anthropometric follow-up of cranial vault growth may considerably add valuable information to current literature focusing on treatment strategies for premature multiple-suture craniosynostosis. The aim of this paper was to compare postoperative growth patterns of nonsyndromic and syndromic multiple-suture craniosynostotic children with sex-matched and age-matched children from the typically developing population. Forty-one multiple-suture craniosynostotic patients (19 nonsyndromic and 22 syndromic) were included in this 5-year follow-up. Anthropological data of sex-matched and age-matched normal Swiss children served as a control. A standardized time protocol for anthropometric skull measurements (head circumference and cephalic index) was used. Data were converted into Z-scores for standardized intercenter comparison. All patients showed a marked benefit in cranial vault shape after open skull remodeling. Significant differences in long-term cranial vault growth pattern could be seen between the nonsyndromic and the syndromic groups compared to the control group.

Postoperative cranial vault growth in premature sagittal craniosynostosis.

Various techniques for the correction of sagittal craniosynostosis have been described in the literature. Nevertheless, there is a lack of consensus regarding surgical procedure and timing, although a long-term anthropometric analysis may shed light on this controversy. The aim of the current study was to collect serial anthropometric data of children before and after total cranial vault remodeling and to evaluate cranial vault growth pattern. Twenty-nine Swiss children with a surgical age between 8 and 10 months were included in this 5-year follow-up. Anthropologic data of sex- and age-matched healthy Swiss children served as a control. A standardized time protocol (before, after, 6 wk after surgery, 6 mo after surgery, and then annually until the age of six) for anthropometric skull measurements (head circumference, cranial length, breadth, and cephalic index) was used. Data were converted into the z score for standardized intercenter comparison. Postoperatively, all patients showed a marked benefit in cranial vault shape. Significant differences in long-term cranial growth pattern could be seen and a relapse into a dolichocephal skull growth. Both observations were rated as clinically irrelevant.

Cranial vault growth patterns of plagiocephaly and trigonocephaly patients following fronto-orbital advancement: a long-term anthropometric outcome assessment.

Fronto-orbital advancement (FOA) is the most common technique used to correct plagiocephaly and trigonocephaly. The aim of this study was to investigate the cranial vault growth following FOA and to compare the growth pattern to the normal standard. Fifty-two Swiss children (25 with anterior plagiocephaly and 27 with trigonocephaly) between the surgical ages of 8 and 10 months were included in this 5-year follow-up study. A standardised time protocol (before the procedure; 6 weeks and 6 months after the surgery; and then annually until the age of six) for anthropometric skull measurements (head circumference, cranial length, and breadth and cephalic indices) was used to analyse the pre- and post-operative cranial vault growth patterns. Data were converted into the Z-score for standardised inter-centre comparison. For all the patients, a significant improvement in the shape of the cranial vault following FOA was observed. In both the plagiocephaly and trigonocephaly groups, the long-term cranial growth patterns (head circumference and cranial length and breadth) significantly differed following this procedure in comparison to those of the control group. The cephalic indices remained constant; no significant changes were found in either study population. Fronto-orbital advancement in anterior craniosynostotic patients between the ages of 8 and 10 months seems to be ideal, as the procedure promotes solid cranial vault growth, ensuring positive surgical results.

Hybrid distraction: a novel method for distraction osteogenesis of the alveolar process.

Segmental distraction osteogenesis of the anterior alveolar process is a sufficient method to enlarge the alveolar arch. Indications for this method are dental crowding, retroalveolism, and leveling of the curve of Spee. However, after the distraction period, the anterior alveolar segment often shows an unfavorable inclination resulting in nonphysiologic load on the lower incisors.The aim of this paper was to introduce a new approach in segmental distraction osteogenesis of the anterior alveolar process. This new method combines 2 different surgical techniques: a segmental osteotomy for the alveolar ridge with instant fixation in the desired position and a distraction procedure for the alveolar segment. This hybrid distraction avoids an unfavorable inclination of the lower incisors after front-block distraction procedures.

Anterior alveolar segmental osteodistraction with a bone-borne device: clinical and radiographic evaluation.

PURPOSE: Anterior alveolar osteodistraction is a common method for enlargement of the dentoalveolar process, and bone-borne distraction devices are hypothesized to avoid the risk of dental tipping and periodontal impairment during distraction. The aim of this study was to objectify this thesis and to determine the reliability of bone-borne osteodistraction of the anterior alveolar process. PATIENTS AND METHODS: The study group consisted of 18 consecutive patients who underwent anterior alveolar segmental distraction with a bone-borne distraction device for the treatment of dental crowding or alveolar retrusion from 2008 through 2011. Clinical and radiologic changes within the apical base and dentoalveolar process were analyzed after bone-borne distraction osteogenesis. All measurements were carried out using cone-beam computed tomography. RESULTS: Surgery and the postoperative period were uneventful in all patients. Mean alveolar movement was 8.2° ± 2.4°. Skeletal movement was 97.6% and absolute dental tipping was 2.4%. A mean change in the occlusal plane of 1.9° ± 1.1° was verified. The apical base enlargement showed a mean of 7.9 ± 1.4 mm, and the dentoalveolar arch a mean increase of 12.7 ± 2.1 mm. Within the distraction zone, a mean vertical bone loss of 3.5 ± 0.7 mm and a mean horizontal bone loss of 3.9 ± 0.8 mm were seen. After orthodontic gap closure, both were clinically irrelevant, with no need for additional bone grafts. Periodontal impairment (gingival recessions of 1 mm) was observed in 7 patients but affected only the teeth bordering the vertical osteotomy line. CONCLUSIONS: Bone-borne anterior alveolar osteodistraction is sufficient for enlargement of the apical base and the dentoalveolar arch of the mandible. Skeletal movement of the alveolar segment was predictable and dental tipping was clinically irrelevant. This technique presents further indications and approaches in orthognathic surgery.

Osteopathology of the jaw associated with bone resorption inhibitors: what have we learned in the last 8 years?

QUESTIONS UNDER STUDY: 8 years after discovery of osteonecrosis of the jaw associated with bisphosphonate therapy a lot of experience has been garnered in treating 112 patients with this disease. This disease, although uncommon, is still a burden for the patient as well as the treating specialists and an adequate standardised classification as well as therapy does not exist. This article presents a summary of collected patient data, garnered experience and consequential changes in knowledge, in diagnostic measures and therapy. METHODS: The data of in total 112 patients referred to the Special Clinics for patients with bisphosphonate-associated lesions of the jaw was retrospectively analysed and compared with data from the literature. RESULTS: In total, 110 patients, 70% women, were included in the data analysis. A quarter of those patients had osteoporosis as the underlying disease, more than half of all patients had extractions as the local influencing factor. The lesion was localised in the mandible in three quarters of all patients and almost all patients showed clinical signs of infection. In total, 58% of all patients were treated surgically with a complete remission rate of 78% over 7 years. CONCLUSIONS: This summary of patient data and literature shows that knowledge about bisphosphonate-associated osteopathology of the jaw becomes more and more specific. The range of drugs associated with this disease has increased, but also therapeutic options show more and more success. Classifications, published shortly after the discovery of BRONJ need to be revised and new knowledge included.

Innovation in anterior mandibular alveolar distraction osteogenesis: introduction of a new bone-borne distraction device and first clinical results.

Segmental distraction osteogenesis of the anterior mandibular alveolar process (frontblock) is a sufficient method to avoid extractions in patients with dental crowding and to decompensate retroalveolism. Up to now dental-borne devices were used, but limitate the indications for front-block distraction. A new bone-borne distraction device for mandibular alveolar front-block movement is introduced in this study. The distractor allows sufficient segmental transport without loading on the teeth. Clinical evaluations of 7 patients have been performed including the feasibility and predictability of the distraction, postoperative pain and patients' discomfort. The results indicate that this technique is a promising strategy in the correction of dental crowding, correcting the curve of Spee and to decompensate mandibular retroalveolism even in patients with impaired periodontal health and a thin mandibular symphysis.

Segmental distraction osteogenesis of the anterior alveolar process using tooth-borne devices: is it skeletal movement or mainly dental tipping?

PURPOSE: Segmental distraction osteogenesis of the anterior alveolar process has been introduced as a technique designed to avoid extractions in patients with severe dental crowding. The aim of this study was to quantify the degree of dental tipping within the alveolar segment after distraction osteogenesis. PATIENTS AND METHODS: Patients treated for dental crowding, retruded anterior alveolar process, or flat curves of Spee using segmental distraction osteogenesis of the anterior alveolar process were included in the study. Dental-borne distraction devices were used while measuring points, and angles were defined to analyze the amount of dental tipping of the lower incisors after distraction. The measurements were performed using cone-beam computed tomographic scans. Periodontal health (eg, gingival recession, tooth mobility, and dental socket depths) was evaluated after distraction. A descriptive statistical analysis was performed. RESULTS: Fifteen patients were included in the study. The amount of dental tipping within the total movement of the alveolar process showed a mean of 24% after distraction osteogenesis, whereas the skeletal movement was 76%. Dental socket depths and tooth mobility remained at the same levels as those before distraction osteogenesis. In one third of patients, gingival recession was observed around the canines. CONCLUSIONS: Segmental distraction osteogenesis of the anterior process is a powerful technique that can prevent extractions in patients with dental crowding. The technique can also compensate for retruded anterior alveolar process and accelerate or decelerate the curve of Spee. Patients with constricted periodontal health and those with a thin mandibular symphysis, however, cannot be treated with this technique because of the increased risk of dental tipping. Severe gingival recession must also be considered a possible side effect associated with this technique.

The influence of involuntary facial movements on craniofacial anthropometry: a survey using a three-dimensional photographic system.

In the modern anthropometry of complex structures, such as the face, different technical approaches for acquisition of three-dimensional data have become increasingly more common. Results of meticulous evaluations have shown high degrees of precision and accuracy under both ideal and clinical circumstances. However, the question remains as to which level of accuracy is adequate to meet clinical needs. Apart from the measuring technique itself, potential sources of error must be identified and dealt with. Subjects' involuntary facial movements can potentially influence clinical reliability. The 3dMDface™ system was used clinically to investigate the influence of involuntary facial movements. Other factors of influence were systematically excluded. The mean technical error of the system (0.09mm) was investigated in a previous study and taken into account for interpretation of the data. The handling of the system was straightforward for both acquisition and analysis of data. Including technical error and the influence of involuntary facial movements, the mean global error was 0.41mm (range 0-3.3). Taking into account the technical error of the system known from the previous study, involuntary facial movements account for a mean error of 0.32mm. This range of involuntary facial movements clearly exceeds the known technical error of the three-dimensional photographic system used. Given this finding, future research should shift its focus from the analysis of the technical aspects of such systems to other influential factors.

Microvascular tissue transfer in cleft palate patients: advocacy of the prelaminated radial free forearm flap.

The closure of wide palatal clefts and recurrent oronasal fistulae may be challenging. After repeated failure of conventional techniques, microvascular tissue transfer may be indicated in the closure of such fistulae. Depending on the location and the size of the palatal fistula, different tissues are required to sufficiently close the palatal gaps. A subdivision of common flaps into mucosa, muscular, bony, skin, and fascia flaps was carried out to analyze their suitability for alveolar, hard, and soft palate reconstruction. Furthermore, the bulk of flaps and the length of the vascular pedicle were analyzed to rate the suitability of different flaps for palatal closure. Based on a new classification of oronasal fistulae, all these factors were taken into consideration to introduce a decision guidance of what microvascular flap fits a particular clinical situation. The radial free forearm flap was found to be sufficient in the closure of all classes of oronasal fistulae.

Precise screw positioning at the mandibular angle: computer assisted versus template coded.

BACKGROUND: Buried intraoral devices for distraction osteogenesis in mandibular deformities have numerous advantages, but success depends on the precise positioning of these devices. Although most centers nowadays use template-guided techniques for precise positioning, computer navigation has been described as a promising technique. Surgical navigation during device placement could become a viable method because it affords certainty in defining a device position. METHODS: A clinical situation was simulated by means of mounting a mandible model inside a phantom head. Screws were positioned according to a preoperative plan through transoral and transbuccal approaches, with both template-coded and freehand computer navigation. RESULTS: With template-coded navigation, the medium deviation from the planned position was 0.63 mm (range, 0.00-1.24 mm). With commercial freehand surgical computer navigation, the medium deviation was significantly higher at 0.98 mm (range, 0.00-3.13 mm). CONCLUSIONS: Computer-assisted surgery can provide a high level of accuracy in the region of the mandibular angle where precision is crucial for buried intraoral distraction devices. However, template-coded guidance does provide a significantly higher level of accuracy and therefore represents the gold standard.

Comparison of different registration methods for surgical navigation in cranio-maxillofacial surgery.

BACKGROUND: Surgical navigation requires registration of the pre-operative image dataset with the patient in the operation theatre. Various marker and marker-free registration techniques are available, each bearing an individual level of precision and clinical practicability. In this study the precision of four different registration methods in a maxillofacial surgical setting is analyzed. MATERIALS AND METHODS: A synthetic full size human skull model was registered with its computer tomography-dataset using (a) a dentally mounted occlusal splint, (b) the laser surface scanning, (c) five facial bone implants and (d) a combination of dental splint and two orbital bone implants. The target registration error was computed for 170 landmarks spread over the entire viscero- and neurocranium in 10 repeats using the VectorVision2 (BrainLAB AG, Heimstetten, Germany) navigation system. Statistical and graphical analyses were performed by anatomical region. RESULTS: An average precision of 1mm was found for the periorbital region irrespective of registration method (range 0.6-1.1mm). Beyond the mid-face, precision linearly decreases with the distance from the reference markers. The combination of splint with two orbital bone markers significantly improved precision from 1.3 to 0.8mm (p<0.001) on the viscerocranium and 2.3-1.2mm (p<0.001) on the neurocranium. CONCLUSIONS: An occlusal splint alone yields poor precision for navigation beyond the mid-face. The precision can be increased by combining an occlusal splint with just two bone implants inserted percutaneously on the lateral orbital rim of each side.