The "springform" technique in cranioplasty: custom made 3D-printed templates for intraoperative modelling of polymethylmethacrylate cranial implants.

BACKGROUND: Manual moulding of cranioplasty implants after craniectomy is feasible, but does not always yield satisfying cosmetic results. In contrast, 3D printing can provide precise templates for intraoperative moulding of polymethylmethacrylate (PMMA) implants in cranioplasty. Here, we present a novel and easily implementable 3D printing workflow to produce patient-specific, sterilisable templates for PMMA implant moulding in cranioplastic neurosurgery. METHODS: 3D printable templates of patients with large skull defects before and after craniectomy were designed virtually from cranial CT scans. Both templates - a mould to reconstruct the outer skull shape and a ring representing the craniectomy defect margins - were printed on a desktop 3D printer with biocompatible photopolymer resins and sterilised after curing. Implant moulding and implantation were then performed intraoperatively using the templates. Clinical and radiological data were retrospectively analysed. RESULTS: Sixteen PMMA implants were performed on 14 consecutive patients within a time span of 10 months. The median defect size was 83.4 cm2 (range 57.8-120.1 cm2). Median age was 51 (range 21-80) years, and median operating time was 82.5 (range 52-152) min. No intraoperative complications occurred; PMMA moulding was uneventful and all implants fitted well into craniectomy defects. Excellent skull reconstruction could be confirmed in all postoperative computed tomography (CT) scans. In three (21.4%) patients with distinct risk factors for postoperative haematoma, revision surgery for epidural haematoma had to be performed. No surgery-related mortality or new and permanent neurologic deficits were recorded. CONCLUSION: Our novel 3D printing-aided moulding workflow for elective cranioplasty with patient-specific PMMA implants proved to be an easily implementable alternative to solely manual implant moulding. The "springform" principle, focusing on reconstruction of the precraniectomy skull shape and perfect closure of the craniectomy defect, was feasible and showed excellent cosmetic results. The proposed method combines the precision and cosmetic advantages of computer-aided design (CAD) implants with the cost-effectiveness of manually moulded PMMA implants.

Compartment Syndrome of the Temporal Muscle.

The authors report a patient with masticator space abscess due to an ascending infection following a wisdom tooth extraction. They administered antibiotics and did an incision and drainage; however, osteomyelitis of the mandible and compartment syndrome of the temporal muscle complicated the course. The authors suggest a physiopathology and discuss the management of this study.

Off-Label Use of an External Hand Fixator for Craniomaxillofacial Fractures-An Anatomical Feasibility Study.

BACKGROUND: The lack of resources limits the treatment of craniomaxillofacial fractures (CMF) in low-income countries (LIC). Therefore, Barton bandages and/or interdental wiring are considered in these regions. Fracture reduction is maintained by permanent occlusion for 6 weeks, which often leads to limited compliance and dissatisfying results. The aim of this cadaver-based study is to evaluate the feasibility of the use of an external face fixator (EFF) for the treatment of CMF, its biomechanical values and to define the optimal pin insertion points and angles. MATERIALS AND METHODS: An AO hand fixator was used. CMF of types Le Fort 1-3 with split fractures of the hard palate were treated with EFF on 13 anatomical specimens. Fractures were created using a chisel, and pins were placed in specific anatomical regions. The maximal pull-out force [N] of pins was analysed by a tensile force gauge, and Fmax of the mandibular pins was evaluated. Computer tomography scans were performed on the healthy, fractured and EFF-treated skulls. RESULTS: The pull-out forces for the single pins were mandibular pins (n = 15, median 488.0 N), supraorbital pins (n = 15, median 455.0 N), zygomatic pins (n = 14, median 269.1 N), medial hard palate pins (n = 12, median 208.4 N) and lateral hard palate pins (n = 8, median 49.6 N). CONCLUSIONS: The results indicate that the operation technique is feasible, and the stability of the EFF is sufficient for maintaining the reduction. The required pins can safely be inserted into the described areas with good reduction results. Using EFF offers a feasible alternative to the non-surgical treatment of CMF in LIC.

[Oral metastasis of a renal cell carcinoma. A case report concerning the first manifestation of a renal cell carcinoma as bone metastasis in the mandible]. / Orale Metastase eines Nierenzellkarzinoms. Ein Fallbericht über die Erstmanifestation eines Nierenzellkarzinoms als ossäre Metastase im Unterkiefer.

UNLABELLED: Tumorous lesions of the oral cavity are mostly of dental or local pathological origin. On occasion, they may have a distant origin outside the field of dentistry. Under certain circumstances, this can lead to serious consequences. Renal cell carcinomas are known for their frequent metastasis to the lungs, liver, bones, and brain. Metastases to the oral cavity are rare. CASE REPORT: A 68-year-old woman with previously unknown renal cell carcinoma is presented. By biopsy of a suspicious lesion, an intraoral clear cell carcinoma was diagnosed. In the following tumor staging, a metastasizing clear cell renal cell carcinoma was identified as the focus and a systemic therapy was initiated. SUMMARY: This case report exemplarily shows the importance of timely histological verification of each new intraoral lesion. Under certain circumstances, a diagnosis of a surprising and potentially life-threatening condition may be made in time to initiate adequate treatment.

Microvascular reconstruction and dental rehabilitation of benign severely atrophic jaws and defects of the alveolar ridge: our philosophy in 2019.

We deal regularly with patients who present with severe atrophy of the jaws, compromised soft tissue, or penetrating defects of the alveolar ridge that are not the result of malignant disease. For these patients we use microvascular bony flaps together with dental implants and implant-supported prostheses. The purpose of this retrospective study was to present our current management and the lessons we have learned over a 16-year period while treating 86 patients for these indications with 87 microvascular bone flaps. We used a transoral approach for the anastomosis in 60 flaps, thereby avoiding visible scars, and inserted 281 dental implants to support fixed or removable dental prostheses. Two femoral flaps developed partial necrosis, and seven implants were lost. Eighty-five of the 86 patients were satisfied with the improvement in their orofacial function and aesthetics. Poor oral hygiene, active osteomyelitis, and severe bruxism are absolute contraindications.