Accuracy of low-cost alternative facial scanners: a prospective cohort study

INTRODUCTION

Three-dimensional facial scans have recently begun to play an increasingly important role in the peri-therapeutic management of oral and maxillofacial and head and neck surgery cases. Face scan images can be generated by optical facial scanners utilizing line-laser, stereophotography, or structured light modalities, as well as from volumetric data: for example, from cone beam computed tomography (CBCT). This study aimed to evaluate whether two low-cost procedures for the creation of three-dimensional face scan images were capable of producing sufficiently accurate data sets for clinical analysis.

MATERIALS AND METHODS

Fifty healthy volunteers were included in the study. Two test objects with defined dimensions (Lego bricks) were attached to the forehead and the left cheek of each volunteer. Facial anthropometric values (i.e., the distances between the medial canthi, the lateral canthi, the nasal alae, and the angles of the mouth) were first measured manually. Subsequently, face scans were performed with a smart device and manual photogrammetry and the values obtained were compared with the manually measured data sets.

RESULTS

The anthropometric distances deviated, on average, 2.17 mm from the manual measurements (smart device scanning deviation 3.01 mm, photogrammetry deviation 1.34 mm), with seven out of eight deviations being statistically significant. For the Lego brick, from a total of 32 angles, 19 values demonstrated a significant difference from the original 90° angles. The average deviation was 6.5° (smart device scanning deviation 10.1°, photogrammetry deviation 2.8°).

CONCLUSION

Manual photogrammetry demonstrated greater accuracy when creating three-dimensional face scan images; however, smart devices are more user-friendly. Dental professionals should monitor camera and smart device technical improvements carefully when choosing and adequate technique for 3D scanning.

Mixed reality in oral and maxillofacial surgery: a symbiosis of virtual and augmented reality or a pointless technological gadget?

INTRODUCTION

Mixed reality (MR) represents a new evolution in technological development that combines both virtual reality (VR) and augmented reality (AR) to create a blend of the physical and digital worlds. However, the potential role of MR in preoperative diagnostics in oral and maxillofacial surgery has not been scientifically investigated and remains generally unclear. This article presents a workflow that integrated MR in its scheme. It also evaluates the potential benefit of MR compared with its predecessors, VR and AR.

MATERIAL AND METHODS

MR technology was used to plan the surgical treatment of a clinical case with an extensive tumor of the left maxilla. A workflow proposal incorporating both the surgeon and radiation oncologist is presented based on this experience. A total of 10 examiners rated the usability and applicability of MR for daily routines.

RESULTS

MR showed good results during preoperative planning for a surgically extensive case in terms of displaying 3D structures and enhancing the physical and virtual interactions among the examiners. Previously described drawbacks of other VR/AR applications such as nausea and motion sickness were not observed with MR. However, MR seems to lack intraoperative usability, which is a drawback.

CONCLUSION

MR shows great potential in improving the preoperative assessment of 3D DICOM datasets and thus facilitating diagnostic measures. However, further improvements should be made to implement an MR workflow and incorporate it into the clinical treatment planning tree.

Fibular flap for mandibular reconstruction: are there old tricks for an old dog?

Fibular free flap is considered as an "old dog" in reconstructive surgery because it was first described by Taylor and his colleagues in 1975, and was then introduced for mandibular reconstruction by Hidalgo in 1989. There are some "tricks" for fibular free flap that have been used and recognized in many European maxillofacial surgical units over the past decade. These include: 1) harvesting the distal fibula when recipient vessels are distant; 2) flap selection based on the anatomy of perforators; 3) use of the skin paddle for postoperative flap monitoring; 4) protection of the flap's soft-tissue cuff; 5) preventing venous thrombosis which is essential to reduce flap complications; 6) aligning fibular struts and protecting the vascular pedicle when the double-barrel technique is used; 7) minimizing the gap between the double-barrel struts and implementing a long-term follow-up of dental implants; 8) selecting osteosynthesis materials; and 9) learning curve and clinical competence in microvascular reconstruction. We also reviewed current data from the literature, which would be useful for maxillofacial reconstructive surgeons. With these tricks, one can teach an "old dog" "old tricks".

[Iliac crest bone graft with vascular pedicle after Caldwell-Luc procedure]

The standard Caldwell-Luc procedure includes the removal of most of the maxillary sinus mucosa and the introduction of an inferior meatal antrostomy to promote sinus drainage. Pain, chronic relapsing inflammation and loss of volume are typical sequels of this procedure. Partial maxillary resection and iliac crest bone graft harvesting is a new concept and treatment option in such cases. The case of a 64-year-old woman who had previously undergone several unilateral sinus operations is presented. Fluorescein imaging was used to detect bone areas of low blood perfusion in the sinus walls. All affected bone and granulation tissue were removed. After resection, an iliac crest bone graft with vascular pedicle was performed to reconstruct the maxillary defect. Postoperative CT and scintigraphic imaging revealed a vital transplant. At the 10-month follow-up, no inflammation was observed and chronic pain was significantly reduced. The results clearly demonstrate that maxillary resection and iliac crest bone graft harvesting might be an option to treat severe cases of chronic sinusitis. Further prospective studies are necessary to confirm the advantages of this technique.

[Nasal dermoid sinus cyst: accidental coincidence or syndrome association?]

BACKGROUND

Peters anomaly is a rare congenital glaucoma disease. The Peters' plus syndrome is characterized by distinct malformations. As some of the common craniofacial malformations like cleft lip and palate are frequent in Peters' plus syndrome, no nasal dermoid sinus cysts has been reported so far. Nasal dermoid sinus cysts usually present in isolation, although associations to other anomalies or syndromes are possible. The occurrence of such an anomaly may be either accidental, or present a syndrome association.

PATIENTS AND METHOD

One patient with an unilateral cleft lip and Peters' plus syndrome had undergone removal of nasal dermoid sinus cyst previously and was referred for management of recurrent disease. Complete surgical removal and plastic reconstruction was performed.

RESULTS

Concerning the common (lateral) cleft lip nasal deformity with no midline nasal masses, there are reasons for the assumption that a coincidence of both anomalies might be accidental. Especially in Peters' plus syndrome no occurrence of nasal dermoids has thus far been documented. However, the embryological pathway of the frontonasal region differs from lip and palate development in time and location: So unique formation of both lesions seems inconsistent. Complete surgical removal and plastic reconstruction simultaneously or in a second step are recommended.

CONCLUSION

As two cases of arhinia and Peters anomaly have been described in 1978, midline nasal masses might be a possible appearance of Peters' plus syndrome.

[Fulminant MH crisis during the ninth general anaesthesia]

Malignant hyperthermia (MH) is a rare, often life-threatening complication of general anaesthesia. The timely diagnosis of an MH crisis in onset, as a prerequisite for successful therapy, can be difficult for the anaesthetist because of the few and non-specific early symptoms. This is even more so in patients in whom anaesthesia with MH trigger substances has already been performed in the past without any particular complications so leading to a false sense of security with regard to MH sensitivity. The case presented is a healthy young man with a congenital cleft lip, jaw and palette who developed a fulminant MH crisis during his ninth general anaesthesia. Post-operative research into the course of the previous anaesthesias revealed signs of MH crises which however proceeded abortively and were therefore unnoticed. In the case presented, the diagnosis was additionally complicated by the untypical course of the early symptoms. Tachycardia which in 80 % of cases is described as the first symptom of an MH crisis in onset, was at first completely absent and was only moderately pronounced in the full clinical picture of MH. On the other hand, a steady increase in body temperature, a cardinal symptom which usually appears later, was registered early. The suspected diagnosis of MH was then finally confirmed in the fourth hour after start of anaesthesia on the basis of the repeatedly increased end expiratory CO(2) levels. These could not otherwise be explained although several respiratory corrections were performed. Despite immediate MH specific therapy, the crisis developed in the following hour into the full clinical picture: maximum temperature of 41.4 degrees C, end expiratory CO(2) 100mm Hg, consumptive coagulopathy, acute renal failure and shock (systolic blood pressure < 50mm Hg, heart rate 115/minute). After 2 hours of specific intensive therapy, the patient was finally stabilized and transfer to the intensive care unit was possible. 24 hours after the event, the patient was could be extubated without any complications and 2 days later, he was transferred to the normal ward. The intra-operative diagnosis of MH was confirmed 3 days later by means of genetic analysis. Two mutations of the RYR1 gene were identified.

[Etiology and diagnosis of otalgia]

Otalgia is the sensation of pain in the ear, while referred otalgia is pain felt in the ear but originating from a nonotologic source. Ear pain is a diagnostic problem when examination of the ear shows no pathology. Pain in the ear can be caused by inflammation of the external meatus or the middle ear. Nonotogenic otalgia may be due to referred or reflex pain, neuralgia, or to a psychogenic problem. Otalgia may be referred also from primary carcinoma of the head and neck. A thorough understanding of the anatomy of the head and neck is required. Referred pain is due to irritative lesions involving the fifth, ninth, or tenth cranial nerves and spinal nerves C2 and C3. If pathologic problems in the area supplied by these nerves have been ruled out, the neuralgia should be considered in the differential diagnosis. Psychogenic factors must be identified and treated before any type of surgical therapy is recommended. A basic knowledge of neuroanatomy, with emphasis on the cranial nerves, their course, distribution, and function, is also necessary. The complexity of this field may sometimes require the treating physician to call for consultations from colleagues in the fields of oral surgery, neurology, or neurosurgery. The therapy depends of the causes of the ear-ache.

[Reference manager EndNote 4. Further development and new functions]

Bibliography database managers are used to manage information resources: specifically, to maintain a database of references and create bibliographies and reference lists for written works. It should offer tools that let you find and retrieve references quickly, and it should be able to produce the bibliography in the format required for a particular publication. There are many computer programs, but very few stands out as truly useful, time saving, and work enhancing. One of them is EndNote. The reference manager EndNote 4 was recently released in Germany and, as long-time fans of this excellent program, we upgraded from the previous version. The use of the software package EndNote 4 for Windows is described, and we want to report about our own experiences with the new version of this database manager. The main reason for getting EndNote 4 is its clearly improved functions and features: for instance a new library window, a better search functions, an automatic updates and completion of term lists and an improved identification of duplicate references. Altogether EndNote 4 provides also an excellent combination of features and ease of use.

[Certain aspects of plastic surgery in the head and neck area]

The spectrum of plastic surgery in the head and neck area is wide. The indications for as well as potentials and limits too, aesthetic surgery cannot be pressed into a rigid framework. The operative strategy will substantively depend on several factors, including objectivated local findings from, as well as general situation and motivation, of the patient. In plastic surgery the psychological situation of the patient is very often paramount, especially as regards cosmetic aspects. Sometimes the declared motives of the patient hide emotional disorders. Several examples show the practicability and limits. The possibilities of corrective action depend not only on the local findings but also on the surgeon's experience and skill.

[Some viewpoints on ear cleaning]

The present paper discuss the cleaning of the external auditory canal. It is purpose of this article to show that the insertion of foreign bodies in form of cotton buds, into the ear, is absolutely unnecessary and may be a dangerous practice. We conclude that cotton-tipped swab use may be associated with cerumen accumulation.