Fatal systemic allergic reaction following acrylic cranioplasty: a case report

Epidural Effusion as Allergic Reaction Following Polyetheretherketone Cranioplasty: An Illustrative Case and Review of the Literature

Well-described complications of polyetheretherketone (PEEK) cranioplasty in pediatric patients include surgical site infection, post-operative hematoma, cerebral edema, and implant fracture. We present a rare case of hypersensitivity to PEEK presenting as an epidural effusion in a 7-year-old male receiving a PEEK cranioplasty following a decompressive craniectomy. Within three weeks, the patient experienced fever and emesis. Erythrocyte sedimentation rate (ESR) was high (>130 mm/Hr) as well as C-reactive protein (CRP) (6.4 mg/dL). A brain MRI with contrast demonstrated both subgaleal and epidural fluid collections with T2 isointense columns projecting from the galeal surface, through the holes in the implant to the dural surface. The patient appeared clinically well. A sterile tap of the pericranial fluid showed no growth, b2-transferrin was negative, but the IgG level was high (>129.2 mg/dL) in the tap fluid. High-dose steroids reduced the epidural collection, but then the collection returned with steroid wean. A second cranioplasty operation replaced the PEEK flap with autologous bone. Postoperative imaging demonstrated markedly reduced fluid collections and a decreased midline shift. The patient remained clinically intact throughout the experience. PEEK allergy following cranioplasty is a rare entity and must be distinguished from infection or hematoma. Medical treatment with steroids can be attempted, but, if refractory, then appropriate treatment may necessitate removal of the offending PEEK implant.

A systematic review of cranioplasty material toxicity in human subjects

PURPOSE

Local and systemic toxic reactions to implanted materials can result in morbidities. However, little is reported about cranioplasty implants. Therefore, we performed a systematic review on the toxicity of different materials used for cranioplasty implants.

MATERIALS AND METHODS

A systematic search was conducted by browsing the Pubmed, Embase, and Cochrane Library databases. All human studies that identified toxic (aseptic) reactions to any types of material used as cranioplasty implants or onplants, published up to January 1, 2019, were included in the review.

RESULTS

Nineteen studies were identified. Collectively, 36 patients endured some type of toxic reaction to an implanted material. Eleven studies presented several types of toxicity for PMMA cranioplasties in several tissue types. One article highlighted the risk of neurotoxicity for PMMA cranioplasty. Three articles presented toxic reactions to calcium phosphate and titanium implants. Three additional articles presented toxic reactions to PEEK, polypropylene-polyester, and polyethylene.

CONCLUSION

All materials currently used for cranioplasty showed occasional toxicity and morbidities. Therefore, none can be considered completely biologically inert. We found that aseptic inflammatory reactions have been underreported in the literature due to a high incidence of infections with questionable evidence.

Craniofacial Reconstruction by a Cost-Efficient Template-Based Process Using 3D Printing

Craniofacial defects often result in aesthetic and functional deficits, which affect the patient’s psyche and wellbeing. Patient-specific implants remain the optimal solution, but their use is limited or impractical due to their high costs. This article describes a fast and cost-efficient workflow of in-house manufactured patient-specific implants for craniofacial reconstruction and cranioplasty. As a proof of concept, we present a case of reconstruction of a craniofacial defect with involvement of the supraorbital rim. The following hybrid manufacturing process combines additive manufacturing with silicone molding and an intraoperative, manual fabrication process. A computer-aided design template is 3D printed from thermoplastics by a fused deposition modeling 3D printer and then silicone molded manually. After sterilization of the patient-specific mold, it is used intraoperatively to produce an implant from polymethylmethacrylate. Due to the combination of these 2 straightforward processes, the procedure can be kept very simple, and no advanced equipment is needed, resulting in minimal financial expenses. The whole fabrication of the mold is performed within approximately 2 hours depending on the template’s size and volume. This reliable technique is easy to adopt and suitable for every health facility, especially those with limited financial resources in less privileged countries, enabling many more patients to profit from patient-specific treatment.

Cranioplasty: Review of Materials

Cranioplasty remains a difficult procedure for all craniofacial surgeons, particularly when concerning the reconstruction of large lacunae in the skull. Considering the significant clinical and economic impact of the procedure, the search for materials and strategies to provide more comfortable and reliable surgical procedures is one of the most important challenges faced by modern craniofacial medicine.The purpose of this study was to compare the available data regarding the safety and clinical efficacy of materials and techniques currently used for the reconstruction of the skull. Accordingly, the scientific databases were searched for the following keywords autologous bone, biomaterials, cranial reconstruction, cranioplasty, hydroxyapatite, polyetheretherketone, polymethylmethacrylate, and titanium. This literature review emphasizes the benefits and weaknesses of each considered material commonly used for cranioplasty, especially in terms of infectious complications, fractures, and morphological outcomes.As regards the latter, this appears to be very similar among the different materials when custom three-dimensional modeling is used for implant development, suggesting that this criterion is strongly influenced by implant design. However, the overall infection rate can vary from 0% to 30%, apparently dependent on the type of material used, likely in virtue of the wide variation in their chemico-physical composition. Among the different materials used for cranioplasty implants, synthetics such as polyetheretherketone, polymethylmethacrylate, and titanium show a higher primary tear resistance, whereas hydroxyapatite and autologous bone display good biomimetic properties, although the latter has been ascribed a variable reabsorption rate of between 3% and 50%.In short, all cranioplasty procedures and materials have their advantages and disadvantages, and none of the currently available materials meet the criteria required for an ideal implant. Hence, the choice of cranioplasty materials is still essentially reliant on the surgeon's preference.

Enhancing dermal and bone regeneration in calvarial defect surgery

INTRODUCTION

To optimize the functional and esthetic result of cranioplasty, it is necessary to choose appropriate materials and take steps to preserve and support tissue vitality. As far as materials are concerned, custom-made porous hydroxyapatite implants are biomimetic, and therefore, provide good biological interaction and biointegration. However, before it is fully integrated, this material has relatively low mechanical resistance. Therefore, to reduce the risk of postoperative implant fracture, it would be desirable to accelerate regeneration of the tissues around and within the graft.

OBJECTIVES

The objective was to determine whether integrating growth-factor-rich platelet gel or supportive dermal matrix into hydroxyapatite implant cranioplasty can accelerate bone remodeling and promote soft tissue regeneration, respectively.

MATERIALS AND METHODS

The investigation was performed on cranioplasty patients fitted with hydroxyapatite cranial implants between 2004 and 2010. In 7 patients, platelet gel was applied to the bone/prosthesis interface during surgery, and in a further 5 patients, characterized by thin, hypotrophic skin coverage of the cranial lacuna, a sheet of dermal matrix was applied between the prosthesis and the overlying soft tissue. In several of the former groups, platelet gel mixed with hydroxyapatite granules was used to fill small gaps between the skull and the implant. To confirm osteointegration, cranial computed tomography (CT) scans were taken at 3-6 month intervals for 1-year, and magnetic resonance imaging (MRI) was used to confirm dermal integrity.

RESULTS

Clinical examination performed a few weeks after surgery revealed good dermal regeneration, with thicker, healthier skin, apparently with a better blood supply, which was confirmed by MRI at 3-6 months. Furthermore, at 3-6 months, CT showed good biomimetism of the porous hydroxyapatite scaffold. Locations at which platelet gel and hydroxyapatite granules were used to fill gaps between the implant and skull appeared to show more rapid integration of the implant than untreated areas. Results were stable at 1-year and remain so to date in cases where follow-up is still ongoing.

CONCLUSIONS

Bone remodeling time could be reduced by platelet gel application during cranioplasty with porous hydroxyapatite implants. Likewise, layering dermal matrix over such implants appears to promote dermal tissue regeneration and the oshtemo mimetic process. Both of these strategies may, therefore, reduce the likelihood of postsurgical fracture by promoting mechanical resistance.

Temperature elevation during simulated polymethylmethacrylate (PMMA) cranioplasty in a cadaver model

The aims of this study were to: (i) obtain temperature measurements during in vitro polymerisation of polymethylmethacrylate (PMMA) disks of a range of thicknesses; and (ii) obtain tissue temperature measurements at various locations within a skull defect during a simulated PMMA cranioplasty procedure using a cadaver. In vitro, higher temperatures were recorded with increasing PMMA thickness. During the simulated cranioplasty, the maximum temperature was observed inside the PMMA sample, with nearby tissues being exposed to temperatures of greater than 50 degrees C over prolonged periods. There is conflicting information in the literature concerning the sensitivity of brain tissue and bone to elevated temperatures. Preoperatively fabricated PMMA cranioplasty prostheses are recommended.

Cranioplasty using polymethyl methacrylate prostheses

In this retrospective study we attempted to assess the clinical performance of prefabricated polymethyl methacrylate (PMMA) prostheses and to determine whether they outperform intra-operatively moulded PMMA prostheses in reducing operating time, blood loss and surgical complications in elective delayed cranioplasty operations, after decompressive craniectomy, to repair large (> 100 cm2) cranial defects. Patients (n=131) were divided into three groups according to the cranioplasty technique used. Group 1 patients received fresh frozen autograft bone that had been removed at the craniectomy and refrigerated at -80 degrees C. Group 2 included patients whose PMMA prosthesis was moulded intra-operatively. Group 3 patients received a custom-made prefabricated PMMA prosthesis manufactured using computer-aided design/computer-aided manufacturing (CAD/CAM). Group 2 patients required significantly more operating time than both group 1 (p<0.001) and group 3 (p<0.001) patients, but operating time did not differ significantly between groups 1 and 3 (p>0.05). Mean intra-operative blood loss was significantly higher in group 2 than in group 1 (p=0.015) but did not differ significantly between group 1 and group 3 (p>0.05). The infection rate associated with prefabricated PMMA prostheses was lower than that for intra-operatively moulded PMMA prostheses and was comparable to that for autograft bone flaps. A CAD/CAM PMMA prosthesis is an excellent alternative when no autogenous bone graft harvested during craniectomy is available.

[Allergy towards bone cement]

Bone cements based on polymethylmethacrylate are typically used for fixation of artificial joints. Intolerance reactions to endoprostheses not explained by infection or mechanical failure may lead to allergological diagnostics, which mostly focuses on metal allergy. However, also bone cement components may provoke hypersensitivity reactions leading to eczema, implant loosening, or fistula formation. Elicitors of such reactions encompass acrylates and additives such as benzoyl peroxide, N,N-dimethyl-p-toluidine, hydroquinone, or antibiotics (particularly gentamicin). Upon repeated contact with bone cement components, e.g., acrylate monomers, also in medical personnel occasionally hand eczema or even asthma may develop. Therefore, in the case of suspected hypersensitivity reactions to arthroplasty, the allergological diagnostics should include bone cement components.

Clinical evaluation of the polypropylene-polyester knit used as a cranioplasty material

The paper presents clinical evaluation of the polypropylene-polyester knit used as a cranioplasty material.

MATERIAL

Between year 1980 and 2002 275 cranioplastic procedures using the polypropylene-polyester plates Codubix were carried out in the Department of Neurosurgery of the Medical University of Łódź. There were 146 patients who primarily sustained head injuries and 129 non-traumatic patients with craniectomies carried out for various other reasons. In the majority of cases, i.e. in 158 patients, cranioplasty was performed later than 6 months after the primary surgery. The largest implant measured 430 cm2.

RESULTS

Excellent and good outcome was achieved in 92% of the patients whereas the rate of local infection was 8%.

CONCLUSIONS

Codubix knitted polypropylene-polyester implant proved to be useful and a safe cranioplastic material.