Cold Ablation Robot-Guided Laser Osteotome (CARLO®): From Bench to Bedside.

BACKGROUND: In order to overcome the geometrical and physical limitations of conventional rotating and piezosurgery instruments used to perform bone osteotomies, as well as the difficulties in translating digital planning to the operating room, a stand-alone robot-guided laser system has been developed by Advanced Osteotomy Tools, a Swiss start-up company. We present our experiences of the first-in-man use of the Cold Ablation Robot-guided Laser Osteotome (CARLO®). METHODS: The CARLO® device employs a stand-alone 2.94-µm erbium-doped yttrium aluminum garnet (Er:YAG) laser mounted on a robotic arm. A 19-year-old patient provided informed consent to undergo bimaxillary orthognathic surgery. A linear Le Fort I midface osteotomy was digitally planned and transferred to the CARLO® device. The linear part of the Le Fort I osteotomy was performed autonomously by the CARLO® device under direct visual control. All pre-, intra-, and postoperative technical difficulties and safety issues were documented. Accuracy was analyzed by superimposing pre- and postoperative computed tomography images. RESULTS: The CARLO® device performed the linear osteotomy without any technical or safety issues. There was a maximum difference of 0.8 mm between the planned and performed osteotomies, with a root-mean-square error of 1.0 mm. The patient showed normal postoperative healing with no complications. CONCLUSION: The newly developed stand-alone CARLO® device could be a useful alternative to conventional burs, drills, and piezosurgery instruments for performing osteotomies. However, the technical workflow concerning the positioning and fixation of the target marker and the implementation of active depth control still need to be improved. Further research to assess safety and accuracy is also necessary, especially at osteotomy sites where direct visual control is not possible. Finally, cost-effectiveness analysis comparing the use of the CARLO® device with gold-standard surgery protocols will help to define the role of the CARLO® device in the surgical landscape.

Facial Swelling in a Toddler Due to a Metastatic High-Risk Neuroblastoma.

Neuroblastoma is a malignant embryonal tumor derived from the neural crest cells of the sympathetic nervous system. Curative therapy is challenging, especially because early-stage diagnosis in toddlers is difficult. Successful treatment of high-risk neuroblastoma is only achieved in approximately half of the cases and requires an immediate interdisciplinary approach. We present a 34-month-old toddler with swelling of the left side of the face of three days duration and a mandibular mass of unknown duration, which was diagnosed as a metastasis of a neuroblastoma. He also had metastases in the kidney, long bones and skull. Despite the poor prognosis in cases of disseminated skeletal involvement and N-myc amplification, the young patient remained free of recurrence during a follow-up period of 36 months after multidisciplinary treatment. The purpose of this case report is to increase awareness of the clinical features of neuroblastoma among pediatric dentists to support early-stage diagnosis and highlight interdisciplinary management.

Retrobulbar haematoma in the era of anticoagulants.

AIM: The present retrospective study aimed to evaluate the frequency and distribution of retrobulbar haematoma (RBH) among 26 patients (12 male/14 female) who had suffered maxillofacial trauma/surgery, with special focus on anticoagulants, causes of accidents, treatment, and outcome. METHODS: Patient ages ranged from 8 to 94 years, with a mean of 65 years. Among all patients, 43% had received anticoagulant therapy at admission; 92.3% had a previous history of maxillofacial trauma. RESULTS: The most frequent cause of RBH were falls (65.4%), and three patients experienced RBH postoperatively after treatment using polydioxanone foil. Postoperatively (after RBH relief), 33.3% of the patients reported persistent complete visual loss; of these patients, 29% had received anticoagulation therapy, and the oral anticoagulant intake was not documented in further 29% of the patients. CONCLUSION: Awareness of this pathologic process is crucial for preventing permanent loss of vision via early diagnosis and adequate therapy. With increasing age, patients are more likely to receive an anticoagulant, which leads to a higher risk of RBH. Because falling was the most frequent cause of RBH in our patient population and increases in frequency with increasing age, fall prevention is crucial.

The Use of Finite Element Method Analysis for Modeling Different Osteotomy Patterns and Biomechanical Analysis of Craniosynostosis Correction.

PURPOSE: Several post-processing algorithms for 3D visualization of the skull in craniosynostosis with their specific advantages and disadvantages have been already described. The Finite Element Method (FEM) described herein can also be used to evaluate the efficacy of the cutting patterns with respect to an increase in the projected surface area under assumed uniform loading of the manipulated and cut bone segments. METHODS: The FEM analysis was performed. Starting with the classic cranial osteotomies for bifrontal craniotomy and orbital bandeau a virtually mirroring of the unaffected triangular shaped frontal bone was performed to achieve a cup-shaped sphere of constant thickness of 2.5 mm with a radius of 65 mm. Mechanical properties required for the analysis were Young's modulus of 340 MPa and Poisson's ratio of 0.22. Four different cutting patterns from straight to curved geometries have been projected onto the inner surface of the sphere with a cutting depth set to 2/3rds of the shell thickness. The necessary force for the deformation, the resulting tensions and the volume loss due to the osteotomy pattern were measured. RESULTS: Better outcomes were realized with pattern D. The necessary force was 73.6% smaller than the control group with 66N. Best stress distribution was achieved. Curved cutting patterns led to the highest peak of stress and thus to a higher risk of fracture. Straight bone cuts parallel to the corners or to the thighs of the sphere provided a better distribution of stresses with a small area with high stress. Additionally, also with pattern D a surface increase of 20.7% higher than reference was registered. CONCLUSION: As a proof of concept for different cutting geometries for skull molding in the correction of craniosynostosis, this computational model shows that depending of the cutting pattern different biomechanical behavior is achieved.

Comparison of an Er: YAG laser osteotome versus a conventional drill for the use in osteo- odonto-keratoprosthesis (OOKP).

OBJECTIVES: The osteo-odonto-kerato-prosthesis (OOKP) procedure is a complex, multi-stage, multidisciplinary surgical intervention for the treatment of severe corneal blindness. One step of the OOKP consists of creating a precise hole into a tooth in which an optic cylinder is subsequently inserted; its shape must ensure a perfect watertight fit. The Er: YAG laser (L) used in this study is part of CARLO®, the first laser osteotome that enables surgical planning based on computed tomography data, robot guidance, and a precise execution of laser cuts in teeth and bone tissue, using laser photoablation rather than conventional mechanical methods. The purpose of this study was to assess whether the Er: YAG laser is non-inferior compared to a conventional drill. METHODS: Thirty-two bovine incisors were grounded to a thickness of 1.5 mm. In 16 teeth, a 3.5 mm hole was drilled progressively into each tooth, using dental burs (B) of increasing diameter that were attached to a fixed drill machine. In the other 16 teeth, a hole was created using an Er: YAG laser at a wavelength of 2.94 µm (Part of CARLO®). In seven teeth of each group, the cylinder was inserted and fixated with polymethylmethacrylate (PMMA) bone cement. In the remaining seven teeth of each group, the cylinder was inserted without fixation material (press-fit). After bonding and drying, all specimens were stored in water until force measurements were recorded using a uniaxial traction machine. The force required to move the optical cylinder out of the hole in the tooth was measured using an Instron 3344 testing system. Scanning electron microscope (SEM) and light microscope (LM) visualization of the holes created with the laser and the drill were performed in two teeth (SEM)/four teeth (LM) per method. RESULTS: Significant differences (P < 0.001) were found for the following parameters: B PMMA versus B press-fit; B PMMA versus L press-fit; L PMMA versus B press-fit; L PMMA-L press-fit. This shows that PMMA bone cement fixation is superior to press-fit. No significant differences were found between B PMMA-L PMMA (P = 0.93) and B press-fit-L press-fit (P = 0.83). The SEM pictures showed a smoother surface using L. CONCLUSIONS: The laser cut holes were as strong as bur-drilled holes, although SEM pictures showed a smoother surface of the laser cut holes. Hence, laser osteotomes open the possibility to custom fit the hole exactly to the width of the cylinder, which represents a potential advantage of the laser over the conventional bur. Lasers Surg. Med. 51:531-537, 2019. © 2019 Wiley Periodicals, Inc.

An uncommon cause for a non-healing cutaneous fistula in the parotid gland area - A case report.

INTRODUCTION: Orocutaneous fistulae of dental origin are uncommon but well documented in the literature. This condition is often misdiagnosed because of the multiplicity of manifestations and the atypically presentation of the condition. Dental symptoms are rare. This makes diagnosis and treatment a challenging process. PRESENTATION OF A CASE: A 67-year-old patient presented in the emergency room with an abscess in the parotid area. After incision and drainage the patient developed a non-healing fistula in the region of the parotid. Multiple treatment attempts and several investigations did not solve the problem. Finally, a panoramic x-ray showed a hidden, infected and displaced tooth in the right mandibular angle. After surgical extraction of the tooth and fistula excision, healing was uneventful and there was no recurrence. DISCUSSION: Given the diagnostic challenge, the real origin of the condition is frequently only discovered after several unnecessary interventions that may have harmed the patient. The key to early diagnosis is dental examination and dental radiographs. The goal of treatment is the elimination of the infection by surgical extraction of the tooth or non-surgical endodontic therapy. CONCLUSION: Early diagnosis and rapid treatment minimize patient discomfort and reduce the probability of further complications. The differential diagnosis of sinus tract of dental origin should be considered in any case of unclarified non-healing skin lesion in the head and neck area, especially if initial treatments have failed. An early interdisciplinary approach is essential.

Performing partial mandibular resection, fibula free flap reconstruction and midfacial osteotomies with a cold ablation and robot-guided Er:YAG laser osteotome (CARLO®) - A study on applicability and effectiveness in human cadavers.

OBJECTIVE: Aim of the study was to prove the safety, accuracy characteristics of contact-free laser osteotomy executed with the cold ablation and robot-guided Er:YAG laser osteotome in a human cadaver test. MATERIAL AND METHODS: On six human cadavers mandible resections with a swallowtail like pattern were performed with the laser system on each side. The defects were reconstructed with a fibula graft of identical design and enlarged by 0.2 units. Mandibles and fibulas width as well surgery times were recorded. Additionally a Le Fort I and median mandible split were done. Macroscopically, the bone margins were examined for necrosis. RESULTS: Laser osteotomies of the mandible up to a depth of 23 mm were possible without any thermal damage. Repeatability and precision of the system could be easily assessed. With the navigation system precise control of localization was achievable. Mean surgery time for the mandible resection was 13.32 min and for the fibula osteotomy 12.38 min. CONCLUSION: The simply transmission of a cold ablation and robot-guided laser osteotome in an operation room identical environment for surgical interventions could be demonstrated. Precise osteotomy patterns with freedom in the design and carbonisation-free cut surfaces have been shown.

Comparative microstructural analysis of bone osteotomies after cutting by computer-assisted robot-guided laser osteotome and piezoelectric osteotome: an in vivo animal study.

Most industrial laser applications utilize computer and robot assistance, for guidance, safety, repeatability, and precision. In contrast, medical applications using laser systems are mostly conducted manually. The advantages can be effective only when the system is coupled to a robotic guidance, as operating by hand does not reach the required accuracy. We currently developed the first laser osteotome which offers preoperative planning based on CT data, robot guidance, and a precise execution of the laser cuts. In an animal trial, our system was used to create a grid pattern of the same depth on the inner layer of parietal bone in 12 adult sheep. The same bone cuts were done with piezoelectric osteotome on the contralateral side. The micro-CT and histological analysis showed more new mineralized bone in the laser group compared to the piezoelectric group. As well, a cutting pattern with especially a constant osteotomy depth in the laser group was demonstrated. The here presented autonomous osteotomy tool shows not only an advantage in early bone healing stage but additionally sharp bone cuts with a very high accuracy and freely selectable design cuts.

Two case reports with literature review of the EEC syndrome: Clinical presentation and management.

We report on siblings who suffer from EEC syndrome and show our experiences of the "Basel concept" of cleft lip/palate repair based on the early, one-stage closure of all components. It is performed in the age of 3-4 months to provide early normal conditions for anatomy and muscle function.