Papers by Keyword: Cranioplasty

Abstract: The human skull can become fractured or injured through impact and often requires repair through a craniectomy and subsequent cranioplasty, surgery performed to repair defects or damage to the cranium. Challenges related to material choice, which must be biocompatible, and customization for each patient’s anatomy remain. One possible solution is fabrication of patient-specific cranial implants, out of biocompatible polymers, using single point incremental forming (SPIF). In this paper, polyetheretherketone (PEEK) and ultra-high molecular weight polyethylene (UHMWPE) are formed using SPIF at room temperature to manufacture a cranial implant. The SPIF process is used to produce formed parts from which test specimens were extracted to evaluate the tensile performance and thermal properties. Formed cranial implants were impacted using a drop weight to evaluate their suitability under relevant conditions. The geometric conformance of the SPIF process was studied to compare the material behavior for the specified polymers after forming. The results validate that SPIF can be conducted at room temperature with PEEK and UHMWPE biocompatible polymers to enable custom implant manufacturing. However, PEEK exhibited superior performance in terms of tensile strength, geometric conformance, energy absorption, and melting temperature, and is recommended over UHMWPE for future implant applications.

Abstract: Cranioplasty of frontal skull defects are used for cosmetic reasons, helping correct disfigurement, but also play a critical role in protecting intracranial content from exposure and compression. Modern surgical management is based on principles of craniofacial surgery such as early one-stage repair- if possible, exposure of all fracture fragments by well-sited cosmetic incisions, precise internal fixation and definitive soft tissue management. The choice of surgical approach depends on fracture severity, complexity, patient comorbidities, and surgeon preference and experience. In large skull defects, titanium mesh reconstruction offers good alternative to other biomaterials by eliminating the time consuming task of contour moulding. The aim of the study is to provide a comprehensive review of aesthetic and functional outcomes, involving titanium mesh implants associated with native bone reconstruction of frontal area posttraumatic defects. Also, the article is related to the authors own experience, in treating several patients with posttraumatic deformity of the frontal bone, assessing forehead contour aesthetics, pain, nerve function and late cerebral complications. A retrospective study was conducted using records from 14 adult patients, between 21-74 years of age, who underwent reconstruction of depressed frontal bone fractures, by receiving titanium mesh implants, between February 2013- October 2015. All patients had a minimum follow up of 5 months by clinical examination and periodic CT-scans. In order to evaluate the experimental results we follow different clinical parameters than late complications, like facial nerve function, cosmetic outcome, and pain. According our clinical results, titanium mesh is an effective method of forehead reconstruction, which provides predictably good long term results.

Abstract: Calvarial bone defects are due to cranial bone removal at the end of the surgery (decompressive craniectomy), either because of bone involvement of the tumor or as a method to relieve intracranial pressure caused by important cerebral edema secondary to large tumors or traumas. With the progress of biomedical technology, new materials are available for use by surgeons. The titanium mesh implant is a plating platform with a matrix design and MRI compatibility that can be easily shaped, cut, and bent by the surgeon according to the bone defect. It is locked in place by several screws tapped into the bone. Although may different type of materials are currently available there is no consensus for the best method to be used. The aim of this study was to report our experience with titanium mesh implants for cranial repair and reconstruction of bone anatomy.Twenty four patients with decompressive craniectomies that required reconstruction of the calvarial bone defect for which a titanium mesh cranioplasty was used, operated in our Neurosurgery Department between January 2013 and April 2016 where included in this retrospective study. Of the 24 patients, only one had a localized infection complication for which the patient was re-operated and the implant removed with no other complications. No other neurological, infectious and functional complications were observed during or after surgery. All other patients had excellent anatomic and functional results with a positive feedback for the aesthetic aspects of the implant. The use of these bio-compatible materials is a viable, safe and reliable solution for the management of cranial bone defects offering the surgeon a large array of options for the benefit of the patient. It has a proven cost-effectiveness when compared to other customized prosthetics with the same outcomes. The MRI compatibility was proven very useful, especially for neoplasm patients who required frequent cranial imaging follow-ups, and reduced operating time was particularly beneficial to elderly patients.

Abstract: A patient with severe head trauma must was scheduled for cranioplasty. Due to the large defect with complex profile, the surgeons decided to ask for help from engineers who designed the cranioplasty plate using Mimics© and 3-matic© (software produced by Materialise NV) and 3D printed the prototype of the skull and the cranioplasty plate using a ZPrinter 310 machine (patented by MIT). The cranioplasty plate was manufactured following the prototype using Polyether Ether Ketone (PEEK). The surgery was a success as the first intervention using a complex research team for the Central Military Hospital from Bucharest. The paper presents the case evolution and the engineering processing steps (design and manufacturing) of the cranioplasty plate obtaining.

Abstract: Today, there are four known types of grafts for cranioplasty: autogenic grafts (the same bone is reused such) such as bone from cranium, ribs, shinbones, shoulder blades, sternum or ilia, allogenic grafts (the graft originates from another human) such as cartilage, xenogenic grafts (grafts transplanted from animals ex: bovines, pigs, etc.) and alloplastic gra fts (graft consisting of inorganic material) such as celluloid, Polymethylmethacrylate-PMMA, polyetheretherketone-PEEK, hydroxyapatite, polyethylene, silicone, ceramic and other derivatives; metallic implants such as Aluminium, Gold, Silver, Lead, Platinum, Titanium, Tantalum and their alloys. In this paper, the authors perform a comprehensive review of how the techniques have evolved from classic metals to modern biopolymers and how the modern technology will impact the future of cranial reconstruction. Also, comparative aspects related to the use of modern biopolymers like PMMA and PEEK in cranioplasty will be revealed based on surgical experience and clinical cases. Modern technology enables neurosurgeons to understand the threedimensional anatomy of the skull and defect and allows them to be able to create implants perfectly tailored to the size and shape of the defect without neglecting the volumetry of the skull. The best materials of today appear to be PEEK due to their excellent mechanical properties other properties like non-immunogenicity, non-oncogenicity, sterility, biological tolerance and an acceptable price range.

Abstract: Cranioplasty represent surgical repairs of defects or deformities of the skull which may come as a result of trauma or congenital malformations. The notable advance in cranioplasties came with the experimental groundwork in bone grafting, performed in the late 19th century, based on which, the use of autografts for cranioplasty became popular in the early 20th century. With the First and Second World Wars alternative metals and plastics were needed to cover large cranial defects suffered in combat as precious metals became scarce. As time passed metallic bone substitutes have gradually become obsolete and modern non-immunogenic plastics such as Polymethylmethacrylate (PMMA) snf Polyetheretherketone (PEEK) replaced them, the major downside of the technique being represented by the high costs. The authors present a statistic of 25 patients treated over a period of 4 years in 3 major neurosurgical units – which beneffited from the neurosurgical use of biomaterials for the repair of major cranial defects following congenital malformations, post-surgical cranial defects or trauma of the skull. We excluded large bone flaps for decompressive craniotomy. The authors used PMMA (Polymethylmethacrylate) and PEEK-based implants. There were 12 cases in which PMMA was used and 13 cases in which PEEK-based implants were used. The authors present a personal comparrison between the two materials. At the same time, the authors perform a comprehensive review of how the techniques have evolved from simple metal to modern biopolymers and how the modern technology will impact the future of cranial reconstruction

Abstract: Porous polyethylene has been widely used for cranio-maxillofacial procedures due to its highly stable, flexible and has been shown to exhibit rapid soft-tissue and bone ingrowth. Generally, it is available as standard shape which needs to be intra-operatively contoured and manually adapted to fit the defect of each patient. In this study, a technique of producing customized porous polyethylene implant for calvarial defect reconstruction was reported. The technique began with acquiring patients data by computed tomography and was three dimensionally reconstructed using a medical imaging software. The shape of implant was then digitally designed to fit the defect based on the patients anatomy and transferred to three dimensional printing machine to fabricate the implant using proprietary polyethylene formulation as raw material. This technique can be used to cover any cranial defect size, offering similar or even better cosmetic results to standard alloplast cranioplasty while decreasing operation time. This customized porous implant can permit ingrowth of tissue to increase interface stability, implant strength and decrease the risk of infection similarly to commercial product.

Abstract: The necessity for skull patch surface for cranioplasty was introduced and it was divided according to maximum normal curvature in the discrete points after skull patch surface dispersed. Then the tool axis vector was determined by the lead angle of the tool, corresponding to generating the tool path in each area; At last, the implant shaping mold for cranioplasty was produced by five-axis NC machine.

Abstract: Non metallic materials like polyurethane has been successfully used for bone reconstruction in general and specifically in craniofacial and in mandible surgeries as an implantable material. However, any polymer alone cannot be universally successful as a medical device or structural implant because the eventual lack of well defined porous geometry, inherent interconnected porosity, the non dispensable need for a combined mechanical behavior with biological interaction and manufacturing feasibility. In this work, a bioactive material composite with high mechanical strength was designed using a castor oil polyurethane (PU) structure with a functional gradient having a dense core and a porous bioactive surface. The models and replicas for the implants were processed with Rapid Prototyping (RP) techniques and their application (case studies) were fulfilled according to the SUS (Brazilian Health Service) with the support of Santa Tereza Hospital, Petropolis, RJ.

Abstract: We have developed a novel macroporous calcium phosphate cement MCPC® that sets to poorly crystalline apatite after mixing the powder component with an aqueous solution and has interconnective macroporosity We performed cranioplasty on rat model by injecting the new macroporous calcium phosphate cement MCPC®. The mechanical property of the cement is about 12MPa after 24 hours (compression test). The cement matrix is totally transformed into poorly crystalline apatite in 48 hours. This study demonstrates that MCPC® cement was suitable and efficient for parietal bone reconstruction. Its injectability and moldability allows to be used in bone reconstruction surgery and its mechanical properties are compatible to support calvarial reconstruction. In addition, a bone ingrowth onto the BCP granules occurred on time.