Antony Jackson

Bone reconstruction of cranial defects secondary to trauma with custom implants (Cranial reconstruction with implants custom) Cranial bone reconstruction with customized implants after trauma (Cranial reconstruction with implants customized) Summary Introduction. Cranial defects due to trauma are frequent. They are usually repaired in a secondary fashion due to features such as syndrome of the trephined, for brain protection and for cosmetic purposes. Historically, various materials have been used for reconstruction. Materials and methods. Five cases of patients reconstructed with customized polyetheretherketone (PEEK) or polymethyl methacrylate (PMMA) implants are presented. Defects involved the frontal bone, superior orbital rim and orbital roof in four cases, and the lateral area of the frontal bone, the temporoparietal area and the border of the occipital bone in one. In four patients, reconstruction took place between 6 and 12 months after the injury; in one patient, after 25 years. Two cases required tissue expansion before placing the implant. Results. Four patients evolved favourably, with improvement in neurologic symptoms and adequate shape and contour, plus adequate healing of the scalp flaps. One patient had an infection due to Staphylococcus aureus¸ attributed to a mucocele and fistula between the airway and the cranial cavity, leading to removal of the implant. Conclusions. Customized implants are a useful resource for cranial defects. They offer satisfactory results, both functional and cosmetic. Precautions should be taken in treating injuries that involve the frontal sinus, to ensure there is no communication between the airway and the cranial cavity. Key words: PEEK, PMMA, polyetheretherketone, polymethyl methacrylate, prostheses and implants, reconstructive surgical procedures. Introduction The cranial skeletal defects secondary to trauma are common, due to the high frequency of road accidents, urban violence, and even contact sports. Some bone defects may also be due to infections, surgical procedures, or tumours. The treatment of cranial trauma includes craniotomies and removal of bone segments, exposed fractures and intracranial injuries like bruises. Bone defects are repaired in a secondary way, since in many cases the primary repair for the possibility of infection is not indicated. Faced with this panorama, the cranial reconstruction aims for both cosmetic and functional appearance. The functional aspect is considered relief from neurological symptoms due to so-called "sunken flap syndrome" or "trepanado patient syndrome", as well as the intracranial. Content protection also should be considered in the restoration of cosmetic appearance, primarily if the bone defect is located near the face, as it is the case with frontal faults (Figure 1). Autologous and Heterologous alloplastic; materials can be used for the repair of skull bone loss, the latter include metals and plastics. The objective of this work is to present the result of five cases treated by cranial Vault reconstruction with implants alloplastic custom, four of polyetheretherketone (PEEK), and one of porous polymethylmethacrylate (PMMA). These types of alloplastic materials offer advantage indefinitely; They provide mechanical stability, adaptability to the area by rebuilding, biocompatibility and protection of intracranial content, in addition to a good cosmetic result that includes restoring symmetry. They can be sterilized repeatedly and its properties do not alter, also they are compatible with magnetic resonance imaging and computed tomography (CT). Another benefit to consider is the improvement in the symptoms associated with the syndrome of the sunken flap 2, 3 Material and methods A review of patients undergoing surgical treatment by the authors for reconstruction of cranial bone defects that were served between 2008 and 2016, both in a public hospital (UMAE Hospital of Traumatology and orthopaedics "Lomas Verdes", IMSS) was made in one private hospital (ABC Medical Center) in Mexico City. Bone defects were secondary brain injury or craniofacial trauma, as well as subsequent to trauma craniotomy. Patients were evaluated both in clinical form for imaging and computed tomography of fine cuts (1 mm). Patients were treated with cranial implants manufactured and personalised for five male patients. The ages ranged from 15 to 50 years, with an average of 29.2 years. To rebuild areas where the frontal sinus is associated with the supraorbital rim and partly the orbital roof in four cases, and the lateral portion of the front, the temporoparietal area and the edge of the occipital in one case. Four of the five patients had also suffered facial fractures. For the manufacture of the implant, in all cases was performed with a CT scan with cuts to 1 mm which were sent to the manufacturer. They produced four implants polyetheretherketone (PEEK), and one of porous polymethylmethacrylate (PMMA) (table 1). To carry out the reconstruction, it was considered suitable that the patients had between 6 and 12 months of postoperative evolution with the cranial bone defect. Clinically analysed the surgical wound healing and that there was no presence of fistulas, bloody areas, or infection. It included a case of sequelae of polytraumatism, facial fractures and bone loss of the anterior wall of the frontal sinus and partially of the orbital roof on the left side, which had more than 25 years of evolution. Surgical procedures were performed under general anaesthesia and the implants were placed through the scar of the previous coronal access (Figure 2), with the exception of the youngest patient (aged 15), who’s implant was placed through access on the surgical side of skull as per the initial treatment. The reconstruction of cranial loss with the custom implant was performed in a single time in three of the five; in the fourth case, in two times, and in the fifth case, surgery took three times. Sequential procedures were implemented in these two recent patients: initially, was placed in both was a tissue Expander in order to improve the availability of skin for the reconstruction, since the haired skin flap was retracted and was considered insufficient to cover the area rebuilt with the implant (Figure 3). Both expanders (remote valve) placed the parietooccipital region. One of these cases presented cellulite in the expansion area, so it was necessary to remove the Expander, in addition to antimicrobial treatment. A custom implant was placed three months later, to avoid retraction of the haired skin, after verifying the absence of infection. The implants were fixed to the recipient area with plates and screws of titanium from 1.5 mm diameter. Stitches placed in the dura mater were extracted through the holes of the implant and knotted on inner face-mounted the meninges of the implant (Figure 4). Assembly of the coronal access was made in two planes, with nylon gauge 3-0 and 4-0, respectively. In all patients a vacuum closed drainage was used for a period of 3 days, to prevent subcutaneous seroma collection, in addition to promoting the adherence of the flap to the bed and also to the implant. The haired skin sutures were removed 8 days after the intervention. In all cases patients were given antimicrobials, which started before the surgery and continued for 7 days. A postoperative controlled CT in all cases, in addition to monitoring the clinical evolution were practiced. Results The reconstruction the bone loss in the skull of five patients, all of traumatic origin, through the use of implants, custom made to measure from a CT scan. We used four implants polyetheretherketone (PEEK), and one of porous polymethylmethacrylate (PMMA). All defects were reconstructed in the sequela phase, not less than 6-12 months after initial treatment. One of the cases (the older patient) was subjected to reconstruction 25 years after the accident. As already mentioned, in three of the five cases reconstruction were carried out in a single surgical time. The tissue Expander was placed on the case treated in two surgical times, in the first phase. This was filled gradually until sufficient volume was achieved, and then the removal of the Expander and the placement of the planned implant in the second surgical phase. Both procedures were carried out without complications (Figure 5). In the case treated on three surgical occasions, in the first surgery, an osteotomy reduction was performed, fixation of the zygoma and reconstruction of the floor and medial wall of the orbit (by aftermath of the zygoma fractures that are not addressed in the initial attention), in addition to the placement of tissue expander. There was a few days for the removal of the Expander and the placement of the implant in the second surgical time, it presented a picture of skin hyperaemia, which was catalogued as cellulitis, which made it necessary to remove the Expander. The tomographic study showed no subcutaneous collections or in the intracranial cavity. On removing the Expander purulent material was found, and obtained a good clinical response with the use of clindamycin for 10 days. Information was sought from cultures of the Expander and adjacent tissues, which were negative for bacterial growth. To avoid the retraction of the expanded flap, supported by the result of the trans operative cultures and the evolution of the patient, it was decided to carry out the cranial reconstruction with the implant three months after removing the tissue Expander, a third surgical time. The patient evolved without further complications (Figure 6). Surgical access resolved without complications in all cases. In five cases, the dimensions of the implant were suitable, since there was no need to modify the recipient area or the implant at the time of placement. Fixation of all implants in the recipient area with plates and screws of titanium from 1.5 mm diameter were carried out without difficulty and evolved without complications. Within four months of the placement of the custom implant PMMA, the patient presented a clinical picture characterized by frontal skin lesions (papules) and subcutaneous fluctuation of the reconstructed region. The CT scan revealed the presence of a collection in a mucocele-compatible nasofrontal region. It was decided to remove the implant. Purulent material (4 mL), which was sent for culture was found during the operation for removal. Bone defect in the portion found below front that communicated with the nose bone defect was treated by abrasion of the mucosa, bone scarification and filling with muscle and (Gelfoam®) sterile gelatin sponge and was covered with a small flap of local periosteum. Cultivation reported presence of Staphylococcus aureus, which was treated with Vancomycin for 10 days. At the end of 10 months postoperative status is satisfactory. In addition to a favourable clinical resolution, tomographic studies show fistula obliteration; There is no persistence of the bone defect and formation of mucocele. The patient is waiting for a new cranial reconstruction. Our patients have undergone long trails, up to 24 months, in which time we have established a proper healing, stability of the implant and the form of the reconstructed area recovers the symmetry and remains unaltered (except (in the case of the implant removed). Called "the trepanado patient syndrome" or "the sunken flap syndrome" has been described in patients undergoing craniectomy (syndrome of the Allograft or sinking skin flap syndrome), characterized by motor, cognitive deficits and language, headache and other sintomas (.4) the reconstruction of defects of total thickness of skull improve these manifestaciones (.6) four of our patients had suffered cranial bone loss of total thickness and were compatible with this syndrome symptomatology. In the passage of time after the reconstruction, the symptoms decreased. Discussion Reconstruction of cranial defects is a procedure that has been practiced for centuries. Very different materials have been used, ranging from dog bone or autologous until the reconstructed (.2) bone achieved its main objective, the protection of the brain, too, within the scope of functional and aesthetic appearance, reduce the sunken manifestations.2, 4-6 flap syndrome currently is a variety of biological materials and alloplastic for reconstruction of cranial bone losses. You can use autologous bone, although it has disadvantages as the possibility of reabsorption, surgical time is more prolonged, bleeding and morbidity of the donor area. Alloplastic materials include titanium, with the advantages of being biocompatible mesh and malleable, but with the disadvantage of not providing a good outline in areas of considerable dimensions or in areas such as the frontal sinus region, that may cause The methyl methacrylate artefacts in imagology (3) studies has been used widely, but is difficult to mould it and it may cause injury to adjacent tissues due to the exothermic reaction produced during its polymerisation (3) the use of implants designed by computer is not new, since it began in 1995.7 this type of implant, which can be both porous polymethylmethacrylate (PMMA) polyetheretherketone (PEEK), they offer many advantages. The PEEK implants and PMMA can be drilled with a drill bit and inserted screws to fix them; Similarly, if you use self-drilling screws, you can insert these without problems. Note also that it shortens operative time and the donor area morbidity is reduced. Unlike the autologous bone, it is not necessary to wait for the consolidation of a graft or risk is to reabsorb. Another benefit is the resistance, the restitution of the contour of the reconstructed skull and restoration of symmetry, this situation is very notorious when the defect is located in the frontal region. Three crucial requirements are a bed with adequate Vascularity, a skin cover stable and sufficient so there is no local infection. Whatever the severity of the injury, the initial treatment should contribute to these conditions with a view to future reconstruction. If retraction of the flap makes it difficult to cover the implant or involves a risk of exposure, a tissue expander could be used. In the event that the defect communicates with the frontal sinus, it is essential to isolate the latter to reduce the risk of infection because of the continuity with the Airway. In our series we find that it did not require any adjustment of the implants to place them in the recipient area. On the experience that we've had, in order to reduce dead space between the implant and the dural surface, we put some sutures (stay) to attach the dura mater to the internal face of the implant. The use of drains with suction helps prevent the formation of hematomas and seromas, and also favours the adhesion of the attached bed haired skin flap by the implant. We believe that the infection that the reconstructed patient presented with the implant PMMA kept direct relationship with mucocele and existing fistula, because the communication between the top of the upper airway and the frontal sinus. This point should be very present to treat fractures that affect frontal region. (8, 9) Ten months after removal of the implant, the patient is asymptomatic, with favourable evolution and no recurrence of the fistulous imaging data. Despite this, it is considered prudent to wait a few months to try a new reconstruction of the frontal region. Comments The cranial defects secondary to trauma are common. They should be prevented in the treatment of lesions affecting the frontal sinus, to avoid communication between the air and the cranial cavity.  Bone defects are repaired in a secondary way, since in many cases the primary repair has the possibility of infection and is not indicated. Faced with this panorama, the cranial reconstruction aims to both cosmetic and functional appearance, for the repair of skull bone loss materials autologous and Heterologous alloplastic, can be used as in this study. We use the latter in four patients of polyetheretherketone (PEEK), and one of porous polymethylmethacrylate (PMMA).  Custom implants are a useful resource for cranial bone defects, since they provide satisfactory results from the functional and cosmetic point of view. Conclusions Cranial reconstruction is a necessity for patients undergoing craniectomy with bone loss, not only for cosmetic purposes, but also to improve the neurological symptomatology secondary to bone loss, known as trepanado patient syndrome or sunken flap, in addition to providing protection to the brain. According to some authors, the reconstruction of cranial defects with implant custom manufactured from PEEK or PMMA is a good solution. There is insufficient evidence that demonstrates the superiority of one of these materials over the other. (10) our series is small, in five cases, of which only one had complications by infection, attributable to a fistula connecting the upper part of the nasal cavity with the frontal sinus and the presence of a mucocele; that case was the only one in which it was carried out with an implant of PMMA. Another point to consider is the space between the surface of the brain and the inner face side of the implant; It is recommended that this space does not exceed 2 cm, to avoid the formation of hematomas and seromas susceptible of infection (11) have been able to resolve this situation by placing sutures to attach the dura mater to the implant. The technology of three-dimensional printing applied to surgery of the craniofacial skeleton has continually improved since its invention in the Decade of 1980.( 12) Today there is the option of using prosthetics made to measure, from a CT scan, to repair the bone loss. Materials have increased biocompatibility, lightweight and rugged, and can be set in a stable way with plates and screws in the recipient area. In the specific case of custom implants, they constitute a comprehensive solution and practice, which provides excellent cosmetic and functional for this type of reconstruction results. There is still need to define more precisely the specific indications for using reconstruction implants custom. References 1. Manson PN, Crawley WA, Hoopes JE. Frontal cranioplasty: Risk factors and choice of cranial vault reconstructive material. Plast Reconstr Surg. 1986;77:-. Jonkergouw J, van de Vijfeijken SECM, Nout E, Theys T, van de Casteele E, Folkersma H, et al. Outcome in patient-specific PEEK cranioplasty: A two-center cohort study of 40 implants. J Craniomaxillofac Surg. 2016;44:-. 3. Alonso-Rodriguez E, Cebrián JL, Nieto MJ, del Castillo JL, Hernández-Godoy J, Burgueño M. Polyetheretherketone custom-made implants for craniofacial defects: Report of 14 cases and review of the literature. J Craniomaxillofac Surg. 2015;43:-. Ashayeri K, Jackson EM, Huang J, Brem H, Gordon CR. Syndrome of the trephined: a systematic review. Neurosurgery. 2016;79:525-34. 5. Isago T, Nozaki M, Kikuchi Y, Honda T, Nakazawa H. 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Tomographic imaging of the tissue Expander on the posterior portion of the skull. Figure 4. Implant in two pieces, placed in a lateral defect of cranium, occipital front. Note the placement of sutures to approximate the dura mater to the implant (case 2, see table 1). Figure 5. Evolution 18 months after reconstruction with implant left frontoorbitario (case 1, see table 1). Figure 6. Postoperative image of the case 4 to 24 months of postoperative evolution. See the outline of the area frontoorbitaria (see Figure 1 and table 1).