Pit Voss

Bone regeneration in sinus lifts: comparing tissue-engineered bone and iliac bone.

Lifting of the sinus floor is a standard procedure for bony augmentation that enables dental implantation. Although cultivated skin and mucosal grafts are often used in plastic and maxillofacial surgery, tissue-engineered bone has not achieved the same success. We present the clinical results of dental implants placed after the insertion of periosteum-derived, tissue-engineered bone grafts in sinus lifts. Periosteal cells were isolated from biopsy specimens of periosteum, resuspended and cultured. The cell suspension was soaked in polymer fleeces. The cell-polymer constructs were transplanted by sinus lift 8 weeks after harvesting. The patients (n=35) had either one or both sides operated on. Seventeen had a one-stage sinus lift with simultaneous implantation (54 implants). In 18 patients the implants were inserted 3 months after augmentation (64 implants). Selected cases were biopsied. A control group (41 patients: one stage=48 implants, two stage=135 implants) had augmentation with autologous bone only. They were followed up clinically and radiologically for at least 24 months. Both implants and augmentation were significantly more successful in the control group. Failure of augmentation of the tissue-engineered bone was more common after large areas had been augmented. Eleven implants were lost in the study group and only one in the control group. Lifting the sinus floor with autologous bone is more reliable than with tissue-engineered transplants. Although lamellar bone can be found in periosteum-derived, tissue-engineered transplants, the range of indications must be limited.

Preoperative cervical lymph node size evaluation in patients with malignant head/neck tumors: comparison between ultrasound and computer tomography

PurposeThe spread of malignant lymph nodes due to malignancies of the head and neck is systematically observed. However, sentinel lymph nodes in the cervical region, such as in the axillary or supraclavicular regions, are not described. Therefore, precise preoperative lymph node screening of all neck compartments is required.Materials and methodsForty-five patients with a primary malignant tumor in the head and neck area underwent lymph node staging of the head by means of both CT and ultrasound as a preoperative evaluation. The lymph nodes were classified on the origin of the level system proposed by Som et al. (174:837–844, 2000), which is based on the recommendation of the American College of Radiology introduced in 1990. According to the manual measurement of World Health Organization and the Revised Response Evaluation Criteria in Solid Tumors, the longest transversal and longitudinal diameters were measured by ultrasound, while only the two longest transversal diameters were recorded by CT. The study was conducted by two independent observers. These results were compared with the histopathological results as references.ResultsSix hundred and twenty-four lymph nodes were detected, 64 of which were malignant. Most of the transformed lymph nodes were found in level IIa, II b and III. A more precise measurement was given using ultrasound. The correct positive rate of sonographically detected malignant lymph nodes was significantly higher compared to the CT reading.ConclusionCervical lymph node staging can be performed safely by ultrasound. It is a cheap, easy-to-handle and cost-effective diagnostic method. However, only the uppermost regions of the neck are accessible with a linear transducer. Despite this restriction, ultrasound is a reliable and valuable tool for screening lymph nodes in the case of a head or neck malignancy.

Radiologically assisted navigation in cochlear implantation for X-linked deafness malformation

Abstract The X-linked deafness syndrome is characterised by a complex labyrinth malformation with a shortened cochlea with missing bony separation between the cochlea and internal auditory canal and a deviant route of the facial nerve. Cochlear implant surgery in this malformation may be complicated by an unintended electrode insertion into the internal auditory canal. The authors report a new surgical approach: intraoperative three dimensional-volume tomography (3D-VT)-based navigation and direct intraoperative control by 3D-VT. The navigation dataset was based on intraoperative 3D-VT after performing the mastoidectomy and posterior tympanotomy. The cochleostomy was then performed under navigation control. After insertion, the electrode position was directly visualised by 3D-VT. On the basis of the reconstruction results, the electrode position was corrected and an intracochlear insertion resulted. Cochlear implantation in X-linked deafness malformation can be facilitated using intraoperative 3D-VT-assisted navigation and intraoperative 3D-VT control of the electrode position. This approach enhances the precision of navigation and reduces the risk of improper electrode placement and additional surgery in complex malformations. Copyright

Navigation-guided lateral gap arthroplasty as the treatment of temporomandibular joint ankylosis.

PURPOSE This article presents a novel method of navigation-guided lateral gap arthroplasty (LGA) in the treatment of temporomandibular joint ankylosis (TMJA). MATERIALS AND METHODS Six patients with unilateral TMJA from 2007 through 2011 were included in this study. Presurgical planning was performed to determine the amount and extent of ankylosed bone to be resected using the simulation platform. Minimum follow-up was 6 months. Patients were monitored for complications and signs of recurrence. Maximum mouth opening (MO) was measured and compared intra- and postoperatively. RESULTS Preoperative planning was performed at the STN or Accu-Navi workstation. The amount and extent of ankylosed bone to be resected was determined. All 6 LGAs were completed successfully using real-time instrument- and pointer-based navigation. Measurements performed intraoperatively showed that the mean for maximum MO was about 35 to 40 mm and remained the same postoperatively. Follow-up evaluation showed remarkable improvement in function and esthetics, with no signs of recurrence. CONCLUSION Navigation-guided LGA can be regarded a viable option for performing this delicate and complicated surgical procedure.

Navigation-guided resection with immediate functional reconstruction for high-grade malignant parotid tumour at skull base

The authors report a case of navigation-guided tumour ablation of a high-grade epithelial-myoepithelial carcinoma of the right parotid gland extending to the skull base. Immediate functional reconstruction of the mandible with a prosthetic temporomandibular joint and facial nerve was performed. Postoperative follow-up showed no evidence of local tumour recurrence or distant metastasis with satisfactory temporomandibular and facial nerve function.

The Prevention of Medication-related Osteonecrosis of the Jaw.

BACKGROUND Medication-related osteonecrosis of the jaw (MRONJ) is a preventable complication of antiresorptive treatment. It arises in 1-20% of patients with bone metastases of solid tumors and hematologic malignancies and in 0.1-2% of patients being treated for osteoporosis with bisphosphonates. Depending on the underlying disease and medication dosage, the risk of MRONJ can be elevated even in the first year of antiresorptive treatment. The treatment of MRONJ is difficult and often involves surgery of the jaw. METHODS We systematically reviewed publications retrieved by a selective search for literature on the prevention of MRONJ in the PubMed and Cochrane Library databases and with the aid of the Google Scholar search engine. RESULTS 15 of 559 retrieved publications were included in the analysis. The quality of the evidence in the studies was generally moderate to low, with most of them being case series. In one case series of over 1200 patients with multiple myeloma, the incidence of MRONJ was lowered from 4.6% to 0.8% through regular dental checkups and improved oral hygiene. Tooth extraction, in particular, is associated with a high risk of MRONJ. In a retrospective study, 57% of patients who underwent tooth extraction without antibiotic prophylaxis developed MRONJ, compared to 0% with antibiotic prophylaxis. CONCLUSION Before antiresorptive medication is begun, oral hygiene should be improved. Moreover, it seems that perioperative antibiotic prophylaxis and adequate plastic wound closure can often prevent MRONJ. In view of the fact that bisphosphonates can persist in bone for more than 15 years, patients should be thoroughly informed of the risk that antiresorptive treatment can cause MRONJ, and the measures discussed should be initiated.

Real-time image-guided recontouring in the management of craniofacial fibrous dysplasia

OBJECTIVE This report presents our experience using computer-aided recontouring in the surgical management of complex craniofacial fibrous dysplasia with the use of a navigation system developed by the authors. STUDY DESIGN A total of 21 patients (9 men and 12 women) with craniofacial fibrous dysplasia and mean age of 23 years (range, 17-32 years) were included in this study from 2007 to 2012. By creating a mirror image of the unaffected side on the affected side as a virtual treatment template, we completed the recontouring procedures in real time with the aid of the navigation system that we developed (Accu-Navi). The surgical outcome was assessed by superimposing the postoperative computed tomography (CT) images onto the preoperative CT images. RESULTS The precise preoperative simulation and intraoperative navigation enabled the surgeon to complete the recontouring procedure visually. Postoperative CT was compared with the preoperative plan, yielding an average discrepancy of <1.0 mm. Postoperative follow-up found that both facial aesthetics and patient satisfaction improved remarkably. CONCLUSIONS Navigation-guided recontouring shows benefits in improving accuracy and safety for this complicated procedure.

Anterior lingual mandibular bone cavity as a diagnostic challenge: two case reports.

C n 1942, Stafne was the first to report the presence of one cavities in 35 patients. These usually create a ell-demarcated radiolucency in the posterior manibular angle and are synonymously known under ifferent names in the literature: Stafne bone cyst, tatic bone cavity, latent bone cyst, lingual mandibuar bone cavity, mandibular embryonic defect, idioathic bone concavity of the mandible, and developental submandibular gland defect of the mandible. hese cavities occur in the area between the mandiblar first molar and the mandibular angle below the andibular canal outline. Other than this radioraphic presence, they have no real clinical presentaion. They are innocuous convexities in the lingual ortex of the mandible that would be of no conseuence if they did not appear as radiolucency. It may e difficult to distinguish them from more serious onditions such as cysts and benign or malignant umors. Surgical exploration has shown that this hard

Malignant tumors could be misinterpreted as temporomandibular joint disorders

OBJECTIVES This article stresses the importance of exclusion of malignant tumors as a cause of temporomandibular joint disorder, which is usually caused by intra-articular or musculoligamental dysfunction without considering malignant tumors as a cause of such complaints. METHOD AND RESULTS Three patients were referred to us because of persistent and recurrent temporomandibular joint dysfunction. All patients were treated more than once through their general practitioner, ear nose and throat physician, or dental physician without significant improvement. After adequate clinical and radiological examination, malignant tumors were discovered as a cause of such complaints. CONCLUSIONS Patients with primary or secondary tumors could present with symptoms simulating temporomandibular joint disorder and will therefore be treated similarly. In such condition, missing that rare cause will consequently lead to unnecessary delayed diagnosis and may cost the patients their lives.

Numb chin as signal for malignancy-primary intraosseous diffuse large B-Cell lymphoma of the mandible

Malignant lymphomas are about 5% of all malignant tumors. Extranodal non-Hodgkins lymphomas (NHLs) are found in 26% of these cases. Lymphomas of the head-and-neck area occur in 2%–3% of all malignancies, with 28% with an extranodal manifestation. Extranodal NHLs in the oral cavity are usually found in the maxilla, and rarely in the mandible. Their symptoms and clinical manifestation have no pathognomonic features; therefore, the expression of this uncommon entity can be diagnosed with an odontogenic inflammatory process, leading to a misdiagnosis. Delay in the decision for a biopsy, and adequate treatment for the patient directly impairs the prognosis of this neoplasm. This study reports a case of a patient with discomfort in the right mandible and paresthesia of the right lower lip and chin without any dental focus. After performing further diagnostic examinations including a subsequent biopsy, the final diagnosis was a diffuse large B-cell lymphoma (DLBCL). Intraosseous DLBCLs are uncommon in the daily clinical routine, but emphasize the need for careful examination by the clinicians also considering the differential diagnosis of sensory neuropathy. Neurological symptoms with no apparent cause should raise the suspicion of malignancy until the opposite is proven.