Karri Mesimäki

Novel maxillary reconstruction with ectopic bone formation by GMP adipose stem cells

Microvascular reconstruction is the state-of-the-art in many fields of defect surgery today. Currently, reconstruction of large bony defects involves harvesting of autologous bone causing donor site morbidity and risk of infection. Specifically, utilizing autologous adipose stem cells (autoASCs), large quantities of cells can be retrieved for cell therapy applications and the risk of tissue rejection is diminished. The authors describe the first case report of a microvascular custom-made ectopic bone flap employing good manufacturing practice (GMP) level ASCs. The patient underwent a hemimaxillectomy due to a large keratocyst. After 36 months of follow-up, the defect was reconstructed with a microvascular flap using autoASCs, beta-tricalcium phosphate and bone morphogenetic protein-2. ASCs were isolated and expanded in clean room facilities according to GMP standards and were characterized in vitro. After 8 months of follow-up, the flap had developed mature bone structures and vasculature and was transplanted into the defect area. Postoperative healing has been uneventful, and further rehabilitation with dental implants has been started. The in vitro characterization demonstrated multipotentiality and mesenchymal stem cell characteristics in ASCs. This is the first clinical case where ectopic bone was produced using autoASCs in microvascular reconstruction surgery and it will pave way for new clinical trials in the field.

Patient‐specific reconstruction with 3D modeling and DMLS additive manufacturing

Purpose – The purpose of this paper is to develop a workflow for 3D modeling and additive manufacturing (AM) of patient‐specific medical implants. The comprehensive workflow consists of four steps: medical imaging; 3D modelling; additive manufacturing; and clinical application. Implants are used to reconstruct bone damage or defects caused by trauma or disease. Traditionally, implants have been manually bent and shaped, either preoperatively or intraoperatively, with the help of anatomic solid models. The proposed workflow obviates the manual procedure and may result in more accurate and cost‐effective implants.Design/methodology/approach – A patient‐specific implant was digitally designed to reconstruct a facial bone defect. Several test pieces were additive manufactured from stainless steel and titanium by direct metal laser sintering (DMLS) technology. An additive manufactured titanium EOS Titanium Ti64 ELI reconstruction plate was successfully implanted onto the patients injured orbital wall.Findings...

Rapid prototyped patient specific implants for reconstruction of orbital wall defects

Defects of orbital walls can be reconstructed using implants. The authors report a safe and accurate method to reconstruct bone defects in the orbital area using patient specific implants. A detailed process description of computer aided design (CAD) reconstructive surgery (CRS) is introduced in this prospective study. The 3D volumetric virtual implant was design using MSCT data and PTCProEngineer™ 3D software. The intact orbital cavity of twelve patients was mirrored to the injured side. Specific ledges steered the implant into correct place. Postoperatively the position was assessed using image fusion. One implant (8%) was rejected due to chemical impurities, two (16%) had a false shape due to incorrect CAD. Data of thin bone did not transfer correctly to CAD and resulted in error. One implant (8%) was placed incorrectly. Duration of the CRS was in average 1.17 h, correspondingly 1.57 h using intraoperative bending technique. The CRS process has several critical stages, which are related to converting data and to incompatibility between software. The CRS process has several steps that need further studies. The data of thin bone may be lost and disturb an otherwise very precise technique. The risk of incorporating impurities into the implant must be carefully controlled.

A rare case of spinal cord metastases from oral SCC

Oral squamous cell carcinoma (SCC) tends to spread by direct extension, lymphatic metastases and has low incidence of haematogenous spread. Intramedullary and intradural spinal cord metastases are rare in general. We present a patient case with an aggressive oral SCC which developed intradural and intramedullary multiple spinal cord metastases.

Impairment of wound healing after operative treatment of mandibular fractures, and the influence of dexamethasone

Our aim was to clarify the incidence of impaired wound healing after open reduction and ostheosynthesis of mandibular fractures, and to find out whether the use of dexamethasone during the operation increased the risk. Patients were drawn from a larger group of healthy adult dentate patients who had participated in a single-blind, randomised study, the aim of which was to clarify the benefits of operative dexamethasone after treatment of facial fractures. The present analysis comprised 41 patients who had had open reduction and fixation of mandibular fractures with titanium miniplates and monocortical screws through one or 2 intraoral approaches. The outcome variable was impaired healing of the wound. The primary predictive variable was the perioperative use of dexamethasone; other potential predictive variables were age, sex, smoking habit, type of fracture, delay in treatment, and duration of operation. Wound healing was impaired in 13/41 patients (32%) (13/53 of all fractures). The incidence among patients who were given dexamethasone and those who were not did not differ significantly. Only age over 25 was significantly associated with delayed healing (p=0.02). The use of dexamethasone 30 mg perioperatively did not significantly increase the risk of impaired wound healing in healthy patients with clinically uninfected mandibular fractures fixed with titanium miniplates through an intraoral approach. Older age is a significant predictor of impaired healing, which emphasises the importance of thorough anti-infective care in these patients during and after the operation.

Rapid prototyping modelling in oral and maxillofacial surgery: A two year retrospective study

Background The use of rapid prototyping (RP) models in medicine to construct bony models is increasing. Material and Methods The aim of the study was to evaluate retrospectively the indication for the use of RP models in oral and maxillofacial surgery at Helsinki University Central Hospital during 2009-2010. Also, the used computed tomography (CT) examination – multislice CT (MSCT) or cone beam CT (CBCT) - method was evaluated. Results In total 114 RP models were fabricated for 102 patients. The mean age of the patients at the time of the production of the model was 50.4 years. The indications for the modelling included malignant lesions (29%), secondary reconstruction (25%), prosthodontic treatment (22%), orthognathic surgery or asymmetry (13%), benign lesions (8%), and TMJ disorders (4%). MSCT examination was used in 92 and CBCT examination in 22 cases. Most of the models (75%) were conventional hard tissue models. Models with colored tumour or other structure(s) of interest were ordered in 24%. Two out of the 114 models were soft tissue models. Conclusions The main benefit of the models was in treatment planning and in connection with the production of pre-bent plates or custom made implants. The RP models both facilitate and improve treatment planning and intraoperative efficiency. Key words:Rapid prototyping, radiology, computed tomography, cone beam computed tomography.

The use of anatomically drop-shaped bioactive glass S53P4 implants in the reconstruction of orbital floor fractures—A prospective long-term follow-up study

An isolated fracture of the orbital floor needs reconstruction if there is a clear herniation of adipose tissue or of the rectus inferior muscle into the maxillary sinus. A prospective study was carried out treating 20 patients with an isolated blow-out fracture of the orbital floor or with a combined zygomatico-orbito-maxillary complex fracture, using a newly designed anatomically drop-shaped implants made of bioactive glass (BAG) S53P4. Computed tomography (CT) was performed immediately postoperatively to confirm the correct position of the plate. The patients were followed up for an average of 32 months clinically and radiologically with magnetic resonance imaging (MRI) for an average of 31 months. None of the patients had any signs of complications related to the implant and the clinical outcome was very good. None of the patients had persisting diplopia. The level of the pupillas was normal in 15 of 20 patients. Minor hypo-ophthalmos ranging from 0.5 to 1.0 mm was observed in three patients, and moderate hypo-ophthalmos of 2.0 mm was seen in one patient. Hyperophthalmos of 1.0 mm was seen in one patient. Minor enophthalmos on the operated side ranging from 0.5 to 1.0 mm was seen in eight patients. Mild to moderate paraesthesia of the infraorbital nerve was observed in six patients. The immediate postoperative CT and the long term follow-up MRI revealed that the drop-shaped BAG implants retained their correct position in the orbital floor and did not show any evidence of losing their original shape or material resorption. No adverse tissue reaction was associated with the material. Due to the anatomical drop shape, the implants could successfully maintain the orbital volume and compensate for the retrobulbar adipose tissue atrophy.

Rapid prototyped patient specific guiding implants in critical mandibular reconstruction

Large tumours of the mandible need immediate reconstruction to provide continuity of the mandible, satisfactory function of the jaw, as well as an acceptable aesthetic outcome. In this prospective study we described the immediate reconstruction of the mandible using computer aided design and 15 rapid prototyped patient specific implants (PSI) in 14 patients suffering from benign or malignant tumours demanding continuity resection of the mandible. The scaffold PSI was filled with β-tricalcium phosphate granules and autologous bone. Microvascular reconstruction was additionally needed in 12/15 cases. The clinical follow up was on average 33 months and the radiological follow up was on average 21 months. In nine cases the healing was uneventful. One patient lost the microvascular flap during the first postoperative week and one patient needed a revision due to perforation of the mucosa at the site of the PSI. Four patients had a major complication due to perforation of the mucosa leading to infection, which resulted in the total or partial removal of the PSI. The PSI seems to be a promising solution for treatment of patients demanding large reconstruction after mandible resection. The benefits are decreased rate of donor site complications and more accurate and prompt surgical procedure.

Rapidly growing and ulcerating metastatic renal cell carcinoma of the lower lip: A case report and review of the literature.

Renal cell carcinomas (RCCs) have a tendency to metastasize at an early stage, therefore, the patients frequently exhibit metastatic disease at the time of diagnosis. Common locations for the metastases are adjacent organs and abdominal lymph nodes; however, occasionally metastasis to the peripheral organs may be the initial clinical symptom. The 71-year-old male patient in the current case suffered from radioresistant and aggressively behaving RCC metastasis in the mandible and lower lip, which was successfully managed by surgical resection. RCC metastasis to the facial area is considered to be uncommon based on a review of the existing literature. RCC are somewhat radioresistant and therefore, palliative surgery must be considered when treating patients with this metastatic disease.

A rare case of oral epithelioid sarcoma of the gingiva.

Epithelioid sarcoma (ES) is a rare malignant soft tissue tumor. ES can be classified into proximal, distal, and fibroma-like subtypes. These tumors show both mesenchymal and epithelial immunophenotypes. Microscopically, the proximal type ES is usually characterized by nodules of spindle and epithelioid cells growing in granuloma-like pattern often presenting with central necrosis. Immunohistochemically these tumors are vimentin, pancytokeratin, and usually EMA (80%) positive. CD34 (50%) and CD99 (25%) may be positive, and occasionally SMA and S-100 immunopositivity has been reported. No specific genetic alterations have been found in ES. As far as we know, this is the first case in the literature to present ES in gingival mucosa.