Custom-made titanium cranioplasty: early and late complications of 151 cranioplasties and review of the literature

Consensus on the prevention and repair of titanium mesh exposed wound after cranioplasty (2024 edition)

Titanium mesh exposure after cranioplasty is the most serious complication of this procedure. Although some clinical experience has been gradually accumulated over the years in the diagnosis and treatment of titanium mesh exposure, the treatment is often not standardized and it is difficult to achieve satisfactory repair results due to insufficient understanding of its pathogenesis and concurrent infections. To normalize the diagnosis and treatment of titanium mesh exposed wounds after cranioplasty and improve the therapeutic effect and the quality of life of patients, the Wound Repair Professional Committee of Chinese Medical Doctor Association organized an expert discussion based on the literature and current diagnosis and treatment status of titanium mesh exposed wounds after cranioplasty at home and abroad, and reached a consensus on the pathogenesis, preventive measures, and diagnosis and treatment strategies of titanium mesh exposed wounds after cranioplasty to provide reference for relevant clinicians.

Design of customized implants and 3D printing of symmetric and asymmetric cranial cavities

A methodology has been developed in this work to design customized cranial implants from computed tomography (CT) scan images for symmetric as well as asymmetric defects. The two-dimensional CT scan images were converted into three-dimensional geometric models using software packages. Two cases of cranial cavities at different locations were considered for implant design using two different approaches. Case 1 is having a symmetric cranial cavity while Case 2 has an asymmetric frontal cranial cavity. The craniums with defects were 3D reconstructed. Customized cranial implants were made for the two cases. In Case 1, symmetry was used to design the cranial implant. Symmetry cannot be used in Case 2. In Case 2, the implant was designed by blending from the surface available adjacent to the missing portion of the cranium. 3D reconstructed bone models and customized implants were 3D printed in poly-lactic acid (PLA) using a fused deposition modeling process for form and fit evaluation. Finite element analysis was performed to compare the mechanical behavior of bone, and the two biomaterials - polyether ether ketone (PEEK), and Ti6Al4V. Static structural finite element analysis was performed to simulate the impact of falling off a bicycle with an impact on the cranial implants in the two cases. The load was modeled as a normal force acting on the surface of the implant. It was found that the stresses in the titanium alloy are comparable to those of PEEK for both the cases. However, the strains and deformation were found to be much smaller compared to those in PEEK. Therefore, the titanium alloy is the material of choice for both the cases among the materials under consideration. The designed implants are solid hence may face the challenge in bone ingrowth. In future studies, the implant can be made porous by incorporating a lattice structure to enhance osseointegration and promote bone ingrowth. Implants for both symmetric and asymmetric defect cases in cranium were successfully designed.

Analysis of the Robotic-Based In Situ Bioprinting Workflow for the Regeneration of Damaged Tissues through a Case Study

This study aims to critically analyse the workflow of the in situ bioprinting procedure, presenting a simulated neurosurgical case study, based on a real traumatic event, for collecting quantitative data in support of this innovative approach. After a traumatic event involving the head, bone fragments may have to be removed and a replacement implant placed through a highly demanding surgical procedure in terms of surgeon dexterity. A promising alternative to the current surgical technique is the use of a robotic arm to deposit the biomaterials directly onto the damaged site of the patient following a planned curved surface, which can be designed pre-operatively. Here we achieved an accurate planning-patient registration through pre-operative fiducial markers positioned around the surgical area, reconstructed starting from computed tomography images. Exploiting the availability of multiple degrees of freedom for the regeneration of complex and also overhanging parts typical of anatomical defects, in this work the robotic platform IMAGObot was used to regenerate a cranial defect on a patient-specific phantom. The in situ bioprinting process was then successfully performed showing the great potential of this innovative technology in the field of cranial surgery. In particular, the accuracy of the deposition process was quantified, as well as the duration of the whole procedure was compared to a standard surgical practice. Further investigations include a biological characterisation over time of the printed construct as well as an in vitro and in vivo analysis of the proposed approach, to better analyse the biomaterial performances in terms of osteo-integration with the native tissue.

Titanium Versus Autologous Bone-Based Cranioplasty: A Systematic Review and Meta-Analysis

At present, there is no gold standard when looking at reconstructive evidence for cranioplasty with the use of autologous bone as well as other synthetic materials. Titanium has been considered recently as a good option due to its unique properties such as strength and biocompatibility. Numerous studies have previously compared titanium with autologous bone for cranioplasty yet no meta-analysis has been performed within the literature to provide guidelines for craniofacial surgeons. A systematic review and meta-analysis were performed as per the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A search of electronic information was conducted to identify all comparative studies of autologous bone vs. titanium implants in cranioplasty following a craniectomy. The primary outcomes were measured as re-operation rates and cosmesis, the secondary outcome measures included the incidence of complications, for example, bone resorption and infection. Five studies were selected, enrolling 323 cases. A high reoperation rate (p > 0.007) was seen in autologous cranioplasty using bone due to the significantly high resorption rate reported in this group. Cosmetic outcomes demonstrated no significant difference between the two groups examined. Finally, costs and infection rates (p > 0.18) were found to be comparable. Overall, titanium implants used in cranioplasty offer lower re-operation rates in comparison to autologous bone grafts whilst there was no major increase in adverse outcomes such as postoperative cost or rates.

Spontaneous fracture of a titanium mesh cranioplasty implant in a child: A case report

BACKGROUND

Titanium mesh cranioplasty is often performed after decompressive craniectomy. Spontaneous fracture of the titanium prosthesis is an extremely rare postoperative complication. Here, we report a 10-year-old boy who presented with a spontaneous fracture of titanium mesh without antecedent head trauma.

CASE SUMMARY

A 10-year-old boy presented with a 1-wk history of a tender bulge over the left temporo-parieto-occipital scalp. He had undergone a temporo-parieto-occipital titanium mesh cranioplasty 26 mo previously. He denied antecedent head trauma. Computerized tomography disclosed a perpendicular fissure in the titanium mesh, suggesting a diagnosis of spontaneous titanium mesh fracture. He underwent a second temporo-parieto-occipital cranioplasty and made an uneventful recovery. Three-dimensional modeling and finite element analyses were used to explore potential risk factors of titanium mesh fracture.

CONCLUSION

We report a case of spontaneous fracture of a titanium mesh cranioplasty implant. The current case and literature review indicate that titanium mesh implants should be well-anchored to the base of bony defects to prevent fatigue-induced fractures.

A Medical-Grade Polycaprolactone and Tricalcium Phosphate Scaffold System With Corticoperiosteal Tissue Transfer for the Reconstruction of Acquired Calvarial Defects in Adults: Protocol for a Single-Arm Feasibility Trial

Background

Large skull defects present a reconstructive challenge. Conventional cranioplasty options include autologous bone grafts, vascularized bone, metals, synthetic ceramics, and polymers. Autologous options are affected by resorption and residual contour deformities. Synthetic materials may be customized via digital planning and 3D printing, but they all carry a risk of implant exposure, failure, and infection, which increases when the defect is large. These complications can be a threat to life. Without reconstruction, patients with cranial defects may experience headaches and stigmatization. The protection of the brain necessitates lifelong helmet use, which is also stigmatizing.

Objective

Our clinical trial will formally study a hybridized technique's capacity to reconstruct large calvarial defects.

Methods

A hybridized technique that draws on the benefits of autologous and synthetic materials has been developed by the research team. This involves wrapping a biodegradable, ultrastructured, 3D-printed scaffold made of medical-grade polycaprolactone and tricalcium phosphate in a vascularized, autotransplanted periosteum to exploit the capacity of vascularized periostea to regenerate bone. In vitro, the scaffold system supports cell attachment, migration, and proliferation with slow but sustained degradation to permit host tissue regeneration and the replacement of the scaffold. The in vivo compatibility of this scaffold system is robust—the base material has been used clinically as a resorbable suture material for decades. The importance of scaffold vascularization, which is inextricably linked to bone regeneration, is underappreciated. A variety of methods have been described to address this, including scaffold prelamination and axial vascularization via arteriovenous loops and autotransplanted flaps. However, none of these directly promote bone regeneration.

Results

We expect to have results before the end of 2023. As of December 2020, we have enrolled 3 participants for the study.

Conclusions

The regenerative matching axial vascularization technique may be an alternative method of reconstruction for large calvarial defects. It involves performing a vascularized free tissue transfer and using a bioresorbable, 3D-printed scaffold to promote and support bone regeneration (termed the regenerative matching axial vascularization technique). This technique may be used to reconstruct skull bone defects that were previously thought to be unreconstructable, reduce the risk of implant-related complications, and achieve consistent outcomes in cranioplasty. This must now be tested in prospective clinical trials.

Trial Registration

Australian New Zealand Clinical Trials Registry ACTRN12620001171909; https://tinyurl.com/4rakccb3

International Registered Report Identifier (IRRID)

DERR1-10.2196/36111

Current Concepts in Cranial Reconstruction: Review of Alloplastic Materials

Cranioplasty for acquired cranial defects can be complex and challenging. Benefits include improved cosmesis, protection of intracranial structures, and restoration of neurocognitive function. These defects can be reconstructed with preserved craniectomy bone flaps, split autografts, or alloplastic materials. When alloplastic cranioplasty is planned, the material should be carefully selected. There is confusion on which material should be used in certain scenarios, particularly in composite defects.

Customised products for orbital wall reconstruction: a systematic review

The purpose of this systematic review was to critically analyse the recent literature and present the state of the art in customised reconstruction of orbital fractures. Three electronic databases and manual search approaches were used to identify relevant articles. Only controlled clinical studies were included. Primary outcome was defined as the status of recovery (complete/partial functional, and aesthetic disturbances). The benefit of intrasurgical navigation should be described. The secondary outcome was defined as the time of surgery, post-surgical events, and hospitalisation. Of the 552 records identified, eight met the inclusion criteria. Post-surgical results regarding recovery were superior in the customised group, and were comparable to the control group in five studies. The time of surgery was shorter in the customised groups, and liquid infusion and time of hospitalisation were reduced. Four studies documented more accurate reconstruction with the use of navigation. All the studies presented at least one bias, and considerable heterogeneity was evaluated. This review found that the use of customised meshes in combination with surgical navigation resulted in more accurate reconstruction. A significant reduction in surgical time was revealed.

Regenerative matching axial vascularisation of absorbable 3D-printed scaffold for large bone defects: A first in human series

BACKGROUND

We describe the first clinical series of a novel bone replacement technique based on regenerative matching axial vascularisation (RMAV). This was used in four cases: a tibial defect after treatment of osteomyelitis; a calvarial defect after trauma and failed titanium cranioplasty; a paediatric tibial defect after neoadjuvant chemotherapy and resection of Ewing sarcoma; and a paediatric mandibular deficiency resulting from congenital hemifacial microsomia.

METHOD

All patients underwent reconstruction with three-dimensional (3D)-printed medical-grade polycaprolactone and tricalcium phosphate (mPCL-TCP) scaffolds wrapped in vascularised free corticoperiosteal flaps.

OUTCOME

Functional volumes of load-sharing regenerate bone have formed in all cases after a moderate duration of follow-up. At 36 cm, case 1 remains the longest segment of load bearing bone ever successfully reconstructed. This technique offers an alternative to existing methods of large volume bone defect reconstruction that may be safe, reliable, and give predictable outcomes in challenging situations. It achieves this by using a bioresorbable scaffold to support and direct the growth of regenerate bone, driven by RMAV.

CONCLUSION

This technique may facilitate the reconstruction of bone defects previously thought unreconstructable, reduce the risk of long-term implant-related complications and achieve these outcomes in a hostile environment. These potential benefits must now be formally tested in prospective clinical trials.

Reconstruction of Cranial Bone Defects Using Polyamide 12 Patient-Specific Implant: Long Term Follow Up

ABSTRACT

The main objective of this study was to evaluate the use of patient-specific polyamide 12 implants in cranial bone defect reconstruction.Ten patients who underwent prior decompression craniectomy were selected for the current study. Skull scanning by computerized tomography was performed and used to make virtual planning of the implants to be transformed into physical implant using selective laser sintering. Cranioplasty was performed through coronal surgical approach where cranial implants were fixated using 2.0-mm mini-screws, and plates. Patients follow-up was from 12 to 36 months. Glasgow Outcome Score recorded 1 (good recovery) for all patients. Patient and surgeon satisfaction for the esthetic outcome were measured using visual analog scale as mean of 10 ± 0 and 9 ± 1, respectively. Cranial symmetry index was calculated as mean score of 98% ± 1%, indicating highly accurate symmetry, and preoperative virtual planning and postoperative outcome were compared for accuracy analysis with a mean difference of 0.3197 ± 0.1649, which indicates high accuracy.Polyamide12 cranial implants seem to offer a promising option to cranial bone reconstruction with patient-specific implants. This study ensures proper cosmetic and clinical outcome.

Histological Processing of CAD/CAM Titanium Scaffold after Long-Term Failure in Cranioplasty

Cranioplasty is a frequently performed procedure after craniectomy and includes several techniques with different materials. Due to high overall complication rates, alloplastic implants are removed in many cases. Lack of implant material osseointegration is often assumed as a reason for failure, but no study has proven this in cranioplasty. This study histologically evaluates the osteointegration of a computer-aided design and computer-aided manufacturing (CAD/CAM) titanium scaffold with an open mesh structure used for cranioplasty. A CAD/CAM titanium scaffold was removed due to late soft tissue complications 7.6 years after cranioplasty. The histological analyses involved the preparation of non-decalcified slices from the scaffold’s inner and outer sides as well as a light-microscopic evaluation, including the quantification of the bone that had formed over the years. Within the scaffold pores, vital connective tissue with both blood vessels and nerves was found. Exclusive bone formation only occurred at the edges of the implant, covering 0.21% of the skin-facing outer surface area. The inner scaffold surface, facing towards the brain, did not show any mineralization at all. Although conventional alloplastic materials for cranioplasty reduce surgery time and provide good esthetic results while mechanically protecting the underlying structures, a lack of adequate stimuli could explain the limited bone formation found. CAD/CAM porous titanium scaffolds alone insufficiently osseointegrate in such large bone defects of the skull. Future research should investigate alternative routes that enable long-term osteointegration in order to reduce complication rates after cranioplasty. Opportunities could be found in mechano-biologically optimized scaffolds, material modifications, surface coatings, or other routes to sustain bone formation.

A Narrative Review of Cell-Based Approaches for Cranial Bone Regeneration

Current cranial repair techniques combine the use of autologous bone grafts and biomaterials. In addition to their association with harvesting morbidity, autografts are often limited by insufficient quantity of bone stock. Biomaterials lead to better outcomes, but their effectiveness is often compromised by the unpredictable lack of integration and structural failure. Bone tissue engineering offers the promising alternative of generating constructs composed of instructive biomaterials including cells or cell-secreted products, which could enhance the outcome of reconstructive treatments. This review focuses on cell-based approaches with potential to regenerate calvarial bone defects, including human studies and preclinical research. Further, we discuss strategies to deliver extracellular matrix, conditioned media and extracellular vesicles derived from cell cultures. Recent advances in 3D printing and bioprinting techniques that appear to be promising for cranial reconstruction are also discussed. Finally, we review cell-based gene therapy approaches, covering both unregulated and regulated gene switches that can create spatiotemporal patterns of transgenic therapeutic molecules. In summary, this review provides an overview of the current developments in cell-based strategies with potential to enhance the surgical armamentarium for regenerating cranial vault defects.

Predictive Factors of Surgical Site Infection Following Cranioplasty: A Study Including 3D Printed Implants

In patients who have undergone decompressive craniectomy (DC), subsequent cranioplasty is required to reconstruct cranial defects. Surgical site infection (SSI) following cranioplasty is a devastating complication that can lead to cranioplasty failure. The aim of the present study, therefore, was to identify predictive factors for SSI following cranioplasty by reviewing procedures performed over a 10-year period. A retrospective analysis was performed for all patients who underwent cranioplasty following DC between 2010 and 2020 at a single institution. The patients were divided into two groups, non-SSI and SSI, in order to identify clinical variables that are significantly correlated with SSI following cranioplasty. Cox proportional hazards regression analyses were then performed to identify predictive factors associated with SSI following cranioplasty. A total of 172 patients who underwent cranioplasty, including 48 who received customized three-dimensional (3D) printed implants, were enrolled in the present study. SSI occurred in 17 patients (9.9%). Statistically significant differences were detected between the non-SSI and SSI groups with respect to presence of fluid collections on CT scans before and after cranioplasty. Presence of fluid collections on computed tomography (CT) scan before (p = 0.0114) and after cranioplasty (p < 0.0000) showed significant association with event-free survival rate for SSI. In a univariate analysis, significant predictors for SSI were fluid collection before (p = 0.0172) and after (p < 0.0001) cranioplasty. In a multivariate analysis, only the presence of fluid collection after cranioplasty was significantly associated with the occurrence of SSI (p < 0.0001). The present study investigated predictive factors that may help identify patients at risk of SSI following cranioplasty and provide guidelines associated with the procedure. Based on the results of the present study, only the presence of fluid collection on CT scan after cranioplasty was significantly associated with the occurrence of SSI. Further investigation with long-term follow-up and large-scale prospective studies are needed to confirm our conclusions.

Decision-Making in Adult Cranial Vault Reconstruction

LEARNING OBJECTIVES

After studying this article, the participant should be able to: 1. Define and classify different types of cranial defects 2. Compare both autologous and alloplastic options for reconstruction 3. Develop an optimal approach for cranial vault reconstruction in various clinical scenarios.

SUMMARY

Defects of the cranium result from various causes, including traumatic loss, neurosurgical intervention, skull tumors, and infection. Cranial vault reconstruction aims to restore both the structural integrity and surface morphology of the skull. To ensure a successful outcome, the choice of appropriate cranioplasty reconstruction will vary primarily based on the cause, location, and size of the defect. Other relevant factors that must be considered include adequacy of soft-tissue coverage, presence of infection, and previous or planned radiation therapy. This article presents an algorithm for the reconstruction of various cranial defects using both autologous and alloplastic techniques, with a comparison of their advantages and disadvantages.

A novel prefabricated patient-specific titanium cranioplasty: reconsideration from a traditional approach

OBJECTIVE

Patient-specific implants (PSI) for cranioplasty are expensive, and cost remains the limiting factor in low- to middle-income countries. The authors describe a novel, reproducible and cost-effective method of designing prefabricated titanium PSI cranioplasty.

METHODS

Ten patients from June 2018 to December 2020 were included in this retrospective study. A three-dimensional stereolithography model was made on a custom-built 3D printer with variable layer heights to produce efficient and accurate details. A certain amount of defect in the temporal region was left uncovered to avoid complications related to temporalis muscle dissection. The stereolithography model with a cranial defect was reconstructed with modelling wax. The wax model was scanned with a blue light visible scanner. The digital data was transferred to the milling machine (Jayon Surgical®, Kerala, India), where a 1-mm-thick sheet of titanium was milled according to the specifications. RFCC scoring system was used for assessing cosmetic outcome.

RESULTS

The mean duration of the surgery was 56.50 min, SD = 14.916 min (range 45-75 min). In 9/10 patients, the RFCC score was 4 points. No other complications were found at a minimum follow-up of 18 months in all patients. The cost per patient was approximately 30,000 INR or 400 US dollars. The average time required for us to get the PSI ready for surgery was about 15 days.

CONCLUSION

The authors demonstrate a novel, cost-effective and reproducible method of PSI using titanium for cranioplasty.

Patient-specific implants for craniomaxillofacial surgery: A manufacturer's experience

Additive manufacturing technologies have enabled the development of customised implants for craniomaxillofacial applications using biomaterials such as polymethylmethacrylate (PMMA), porous high-density polyethylene (pHDPE), and titanium mesh. This study aims to report an Australian manufacturer's experience in developing, designing and supplying patient-specific craniomaxillofacial implants over 23 years and summarise feedback received from clinicians. The authors conducted a retrospective review of the manufacturer's implant database of orders placed for custom craniomaxillofacial implants between 1996 and 2019. The variables collected included material, country of order, gender, patient age, and reported complications, which included a measure of custom implant "fit" and adverse events. The development of critical checkpoints in the custom manufacturing process that minimise clinical or logistical non-conformities is highlighted and discussed. A total of 4120 patient-specific implants were supplied, of which 2689 were manufactured from PMMA, 885 from titanium mesh, and 546 from pHDPE. The majority of the implants were used in Australia (2260), United Kingdom (412), Germany (377), and New Zealand (338). PMMA was the preferred material for cranial implants whereas pHDPE was preferred for maxillofacial applications. Age or gender did not influence the material choice. Implant "fit" and adverse outcomes were used as a metric of implant performance. Between 2007 and 2019 there were 37 infections (0.98%) and 164 non-conformities recorded of which 75 (1.8%) were related to implant 'fit'. Our experience demonstrates a safe, reliable, and clinically streamlined manufacturing process which supports surgeons that require bespoke craniomaxillofacial solutions for reconstruction surgery.

Novel Inorganic Nanomaterial-Based Therapy for Bone Tissue Regeneration

Extensive bone defect repair remains a clinical challenge, since ideal implantable scaffolds require the integration of excellent biocompatibility, sufficient mechanical strength and high biological activity to support bone regeneration. The inorganic nanomaterial-based therapy is of great significance due to their excellent mechanical properties, adjustable biological interface and diversified functions. Calcium-phosphorus compounds, silica and metal-based materials are the most common categories of inorganic nanomaterials for bone defect repairing. Nano hydroxyapatites, similar to natural bone apatite minerals in terms of physiochemical and biological activities, are the most widely studied in the field of biomineralization. Nano silica could realize the bone-like hierarchical structure through biosilica mineralization process, and biomimetic silicifications could stimulate osteoblast activity for bone formation and also inhibit osteoclast differentiation. Novel metallic nanomaterials, including Ti, Mg, Zn and alloys, possess remarkable strength and stress absorption capacity, which could overcome the drawbacks of low mechanical properties of polymer-based materials and the brittleness of bioceramics. Moreover, the biodegradability, antibacterial activity and stem cell inducibility of metal nanomaterials can promote bone regeneration. In this review, the advantages of the novel inorganic nanomaterial-based therapy are summarized, laying the foundation for the development of novel bone regeneration strategies in future.

Security and reliability of CUSTOMBONE cranioplasties: A prospective multicentric study

BACKGROUND

Repairing bone defects generated by craniectomy is a major therapeutic challenge in terms of bone consolidation as well as functional and cognitive recovery. Furthermore, these surgical procedures are often grafted with complications such as infections, breaches, displacements and rejections leading to failure and thus explantation of the prosthesis.

OBJECTIVE

To evaluate cumulative explantation and infection rates following the implantation of a tailored cranioplasty CUSTOMBONE prosthesis made of porous hydroxyapatite. One hundred and ten consecutive patients requiring cranial reconstruction for a bone defect were prospectively included in a multicenter study constituted of 21 centres between December 2012 and July 2014. Follow-up lasted 2 years.

RESULTS

Mean age of patients included in the study was 42±15 years old (y.o), composed mainly by men (57.27%). Explantations of the CUSTOMBONE prosthesis were performed in 13/110 (11.8%) patients, significantly due to infections: 9/13 (69.2%) (p<0.0001), with 2 (15.4%) implant fracture, 1 (7.7%) skin defect and 1 (7.7%) following the mobilization of the implant. Cumulative explantation rates were successively 4.6% (SD 2.0), 7.4% (SD 2.5), 9.4% (SD 2.8) and 11.8% (SD 2.9%) at 2, 6, 12 and 24 months. Infections were identified in 16/110 (14.5%): 8/16 (50%) superficial and 8/16 (50%) deep. None of the following elements, whether demographic characteristics, indications, size, location of the implant, redo surgery, co-morbidities or medical history, were statistically identified as risk factors for prosthesis explantation or infection.

CONCLUSION

Our study provides relevant clinical evidence on the performance and safety of CUSTOMBONE prosthesis in cranial procedures. Complications that are difficulty incompressible mainly occur during the first 6 months, but can appear at a later stage (>1 year). Thus assiduous, regular and long-term surveillances are necessary.

Calcium Phosphate Cement "Space Fill-in" Augmentation in Autologous Cranioplasty for Large Cranial Defect: Additional Technical Consideration and Its Long-term Follow-up

In the skull tumor surgery that requires a large cranial reconstruction, economical one-time surgery is challenging. Calcium phosphate paste (CPC) alone is not applied in the large defect. Other plastic fill-in materials have each drawback. Ready-made implants are costly. The authors present additional technique of CPC cranioplasty combined with mainstay autologous grafts for a large cranial defect. The combination of split rib grafts was augmented by CPC. Tenons were placed for the stability of grafts. Our newly additional technique is that CPC is filled in the small adjacent spaces of autografts, not applied as the simple on-lay graft. We introduced this method to a 57-year-old gentleman with left parietal expansile skull tumor. The aesthetics of the patient has been satisfactory, and there were no complaints about pain in the graft site. In the follow-up period of 8 years, both autologous grafts and CPC were well maintained without marked resorption. This patient could work as a farmer in this period. Our methods fulfilled the requirements of aesthetics and in-situ plasticity for a larger cranial defect.

Complications following titanium cranioplasty compared with nontitanium implants cranioplasty: A systematic review and meta-analysis

Decompressive craniectomy is widely used to treat medically refractory intracranial hypertension. There were still few studies focusing on the complications between titanium cranioplasty with non-titanium materials cranioplasty. Our systematic review and meta-analysis aimed to assess the complications following titanium cranioplasty and to make a comparison with nontitanium materials. A systematic review was used to review titanium cranioplasty characters in recent articles. A systematic literature review and meta-analysis were performed by using PubMed/MEDLINE, Scopus, the Cochrane databases and Embase for studies reporting on cranioplasty procedures that compared complication outcomes between titanium with non-titanium materials. The final 15 studies met inclusion criteria and represented 2258 cranioplasty procedures (896 titanium, 1362 nontitanium materials). Overall complications included surgical site infection, hematoma, implant exposure, seizure, cerebrospinal fluid leak, imprecise fitting. Titanium cranioplasty was associated with a significant decrease in overall complications rate (OR, 0.72; P = 0.007), hematoma rate (OR, 0.31; P = 0.0003) and imprecise fitting rate (OR, 0.35; P = 0.04). However, it also suggested that titanium cranioplasty can be greatly increased implant exposure rate (OR, 4.11; P < 0.00001). Our results confirmed the advantages of titanium cranioplasty in reducing complications including hematoma, imprecise fitting, and also suggested that clinicians should pay more attention to postoperative implant exposure. With new synthetic materials emerging, it would also be interesting to study the cost-effect and functional outcomes associated with cranioplasty materials.

Failures in cranioplasty - A clinical audit & review

Introduction

Cranioplasty, like any other surgical procedure also comes with risk of complications and failure. Failure of cranioplasty may be early or delayed and further can be attributed to the surgical procedure itself or to the reconstruction material used for the procedure. The aim of this clinical audit is to analyze the causes of failure of 14 cases of cranioplasty procedure.

Materials and methods

This retrospective study analyses the causes of failure of 14 cases of cranioplasty over 8 ​years ​at a tertiary care centre and identifies major etiological factors for failure including local and systemic. Further, a correlation between the reconstruction material used for cranioplasty and failure was studied along with other attributable factors such as systemic status of the patient and other local factors.

Results

The study established that there exists a correlation between failure and the biomaterial used for reconstruction. Various etiological factors like infection, flap break down, fixation protocol and foreign body were identified along with time frame of failure. After failure of cranioplasty, feasibility of a secondary cranioplasty has also been factored into this study, with 8 out of the 14 cases being successfully re-operated.

Conclusion

Cranioplasty is a technically demanding and demands certain levels of operator skill levels. While formulating a treatment plan for reconstruction of cranial defects, one has to tailor make a strategy considering several factors such as systemic condition of the patient, status of the cranial surgical site, etiology behind craniectomy, choice of reconstruction material, duration from craniectomy and age of the patient. Inspite of best efforts and ideal reconstruction attempts, failures remain a nagging reality.

The Correlative Factors and Probable Mechanism of Epidural Fluid Collection After Cranioplasty

OBJECTIVE

Epidural fluid collection (EFC) is one of the postoperative complications of cranioplasty and is easily ignored. Not only the predictive factors of EFC formation are unknown, the pathologic mechanisms are also unknown. We determined to analyze the predictive factors and the mechanism of EFC formation.

METHODS

A total of 340 patients underwent cranioplasty were retrospectively analyzed in this study. A series of factors were compared in the EFC and none-EFC groups and farther compared in the progress epidural fluid collection (PEFC) and none-PEFC subgroups to determine the predictive factors. The t test, χ test, and logistic regression analysis were used in statistical analysis.

RESULTS

The rate of EFC formation was 34.41%, and the size of skull defect, preoperative volume of collapse, intraoperative dura suspending, a pre- or intraoperative ventriculoperitoneal shunt (V-P shunt), and an postoperative air bubble in epidural space were predictive factors for EFC formation. Furthermore, the incidence of PEFC was 10.29%, the size of skull defects and intraoperative dura suspending were predictive factors for PEFC formation. The protein ratio and lactate dehydrogenase (LDH) ratio of effusion to serum were >0.5 and 0.6, respectively. There was no adverse prognosis.

CONCLUSIONS

Although EFC can be treated with conservative therapy, we need to emphasize EFC incidence and development. As neurosurgeons, it is necessary to analyze the preoperative predictive factors of EFC, pay attention to the intraoperative details such as dura suspending to prevent PEFC formation, and the early intervention should be performed in the postoperative.

Clinical evaluation of rapid 3D print-formed implants for surgical reconstruction of large cranial defects

BACKGROUND

To clinically evaluate 3D print-formed implant process, using cranioplasty as a proof of concept, to examine its effectiveness and utility as a method of intraoperative implant fabrication.

METHODS

Twelve patients had a 3D print-formed template created for patient-specific implant manufacture. Of these patients, 10 received intraoperatively formed polymethylmethacrylate cranioplasty implants between 2013 and 2019. The 3D print-formed implant templates produced to manufacture these patient-specific implants were generated using patient computed tomography scans and 3D printed using fused deposition modelling technology. Cosmetic and functional results were determined by participating surgeons, in conjunction with a patient questionnaire.

RESULTS

The functional results and stability of the implants were deemed to be favourable by participating surgeons. Three of the 10 patients completed a post-cranioplasty survey, all of whom judged their cosmetic results as good or excellent. At time of writing, the rate of surgical revision was zero and without clinically adverse outcomes.

CONCLUSIONS

3D print-formed implants are an effective method of patient-specific implant formation.

An improved process for the fabrication and surface treatment of custom-made titanium cranioplasty implants informed by surface analysis

Cranioplasty implants are routinely fabricated from commercially pure titanium plates by maxillofacial prosthetists. The differing fabrication protocols adopted by prosthetists working at different hospital sites gives rise to considerable variations in surface topography and composition of cranioplasty implants, with residues from the fabrication processes having been found to become incorporated into the surface of the implant. There is a growing recognition among maxillofacial prosthetists of the need to standardise these protocols to ensure quality and consistency of practice within the profession. In an effort to identify and eliminate the source of the inclusions associated with one such fabrication protocol, the present study examined the surfaces of samples subjected to each of the manufacturing steps involved. Surface and elemental analysis techniques identified the main constituent of the surface inclusions to be silicon from the glass beads used to texture the surface of the implant during fabrication. Subsequent analysis of samples prepared according to a revised protocol resulted in a more homogeneous titanium dioxide surface as evidenced by the reduction in area occupied by surface inclusions (from 8.51% ± 2.60% to 0.93% ± 0.62%). These findings may inform the development of improved protocols for the fabrication of titanium cranioplasty plates.

Alloplastic Cranioplasty Reconstruction: A Systematic Review Comparing Outcomes With Titanium Mesh, Polymethyl Methacrylate, Polyether Ether Ketone, and Norian Implants in 3591 Adult Patients

BACKGROUND

Acquired defects of the cranium represent a reconstructive challenge in patients with calvarial bone loss due to trauma, infection, neoplasia, congenital malformations, or other etiologies. The objective of this study was to compare postoperative rates of infection, local complications, and allograft failures following cranioplasty reconstruction using titanium mesh (Ti), polymethyl methacrylate (PMMA), polyether ether ketone (PEEK), and Norian implants in adult patients.

METHODS

This constitutes the first systematic review of available literature on 4 different methods of alloplastic cranioplasty reconstruction, including Ti, PMMA, PEEK, and Norian implants, using the Newcastle-Ottawa Quality Assessment Scale guidelines for article identification, screening, eligibility, and inclusion. Electronic literature search included Ovid MEDLINE/PubMed, EMBASE, Scopus, Google Scholar, and Cochrane Database. Pearson exact test was utilized at P < 0.05 level of significance (J.M.P. v11 Statistical Software).

RESULTS

A total of 53 studies and 3591 patients (mean age, 40.1 years) were included (Ti = 1429, PMMA = 1459, PEEK = 221, Norian = 482). Polymethyl methacrylate implants were associated with a significantly higher infection rate (7.95%, P = 0.0266) compared with all other implant types (6.05%). Polyether ether ketone implants were associated with a significantly higher local complication rate (17.19%, P = 0.0307, compared with 12.23% in all others) and the highest ultimate graft failure rate (8.60%, P = 0.0450) compared with all other implant types (5.52%).

CONCLUSIONS

This study qualifies as a preliminary analysis addressing the knowledge gap in rates of infection, local surgical complication, and graft failure in alloplastic cranioplasty reconstruction with different implant types in the adult population. Longer-term randomized trials are warranted to validate associations found in this study.

Comparison of complications in cranioplasty with various materials: a systematic review and meta-analysis

Objective: Meta-analysis to evaluate complications in the use of autogenous bone and bone substitutes and to compare bone substitutes, specifically HA, polyetheretherketone (PEEK) and titanium materials.Methods: Search of PubMed, Cochrane, Embase and Google scholar to identify all citations from 2010 to 2019 reporting complications regarding materials used in cranioplasty.Results: 20 of 2266 articles met the inclusion criteria, including a total of 2913 patients. The odds of overall complication were significantly higher in the autogenous bone group (n = 214/644 procedures, 33.2%) than the bone substitute groups (n = 116/436 procedures, 26.7%, CI 1.29-2.35, p < 0.05). In bone substitutes groups, there was no significant difference in overall complication rate between HA and Ti (OR, 1.2; 95% CI, 0.47-3.14, p = 0.69). PEEK has lower overall complication rates (OR, 0.51; 95% CI, 0.30-0.87, p = 0.01) and lower implant exposure rates (OR, 0.17; 95% CI, 0.06-0.53, p = 0.002) than Ti, but there was no significant difference in infection rates and postoperative hematoma rates.Conclusions: Cranioplasty is associated with high overall complication rates with the use of autologous bone grafts compared with bone substitutes. PEEK has a relatively low overall complication rates in substitutes groups, but still high infection rates and postoperative hematoma rates. Thus, autologous bone grafts should only be used selectively, and prospective long-term studies are needed to further refine a better material in cranioplasty.

Craneoplastía con implante de polimetilmetacrilato (PMMA) para corregir secuela de trauma. Reporte de caso

Introducción: los defectos del cráneo y las anomalías del hueso craneofacial que requieren reconstrucción son comunes en una variedad de procedimientos neuroquirúrgicos. Después de una craniectomía o de fracturas craneofaciales posteriores a traumatismos cráneoencefálicos, los pacientes pueden desarrollar defectos cosméticos importantes. Algunos de estos son la depresión de la piel y un defecto de hundimiento que lleva a una apariencia asimétrica de la cabeza, sin dejar de lado las repercusiones físicas, neurológicas y psicológicas que estas lesiones conllevan. La reconstrucción craneofacial y la craneoplastía tienen una larga historia, pero las nuevas técnicas quirúrgicas y una multitud de opciones de materiales han impulsado recientemente el avance en esta área. Los implantes de polimetilmetacrilato (PMMA) han demostrado ser estables, biocompatibles, no conductores, radiotransparentes y de bajo costo. Es así que se pueden colocar y modificar fácilmente, con lo que se elimina la morbilidad del sitio donante. Presentación del caso: en este artículo presentamos un caso de craneoplastía de defecto frontal, posterior a traumatismo, cuya reconstrucción fue realizada mediante una prótesis de polimetilmetacrilato (PMMA) en el Hospital General Xoco de la Cuidad de México. Conclusión: se reporta la reducción del tiempo quirúrgico, además de un costo de la prótesis accesible para el paciente; de esta manera, se obtuvieron resultados satisfactorios y mejoras en el contorno estético facial, en tanto se permitió cobertura y protección para el tejido encefálico.La reconstrucción craneofacial y la craneoplastía tienen una larga historia, pero las nuevas técnicas quirúrgicas y una multitud de opciones de materiales han impulsado recientemente el avance en esta área.1 Los implantes de polimetilmetacrilato (PMMA) han demostrado ser estables, biocompatibles, no conductores, radiotransparentes y de bajo costo.6 Se pueden colocar y modificar fácilmente y se elimina la morbilidad del sitio donante. En este artículo presentamos un caso de craneoplastía de defecto frontal posterior a traumatismo realizada mediante una prótesis de polimetilmetacrilato (PMMA) en el Hospital General Xoco de la Cuidad de México, con la cual se logró reducir el tiempo quirúrgico, además el costo de la prótesis fue accesible para el paciente y se obtuvieron resultados satisfactorios.

Negative Pressure Wound Therapy With Chymotrypsin Irrigation: A Maximal Implant Retention Procedure Treating the Exposure/Infection of Titanium Mesh in Cranioplasty

This preliminary study aims to investigate the effects of a maximal implant retention procedure. The authors retrospectively reviewed the use of negative pressure wound therapy with chymotrypsin irrigation treating implant infection/exposure in titanium mesh cranioplasty by comparing patients with titanium mesh totally retained, partially removed, or totally removed according to the evaluation during the surgery. Negative pressure wound therapy with chymotrypsin irrigation was applied 5 days after the surgery. The negative pressure was set at -125 to -150 mmHg. A total of 21 patients were included, 4 patients treated with titanium mesh totally removed; 3 patients treated with titanium mesh partially removed; and 14 patients treated with U-shape debridement with titanium mesh preserved completely. However, 1 patient in the U-shape group required a second debridement to remove all implant. Negative pressure wound therapy with chymotrypsin irrigation is a novel procedure and could be used to treat implant-related infection without the exchange of implant.

Comparison of two different titanium cranioplasty methods: Custom-made titanium prostheses versus precurved titanium mesh

Background:

The aim of this study was to compare the results of two different titanium cranioplasties for reconstructing skull defects: standard precurved mesh versus custom-made prostheses.

Methods:

Retrospective analysis of 23 patients submitted to titanium cranioplasty between January 2014 and January 2019. Ten patients underwent delayed cranioplasty using custom-made prostheses; and 13 patients were treated using precurved titanium mesh (ten delayed cranioplasties, and three single-stage resection- reconstructions). Demographic, clinical, and radiological data were recorded. Results and complications of the two methods were compared, including duration of surgery, cosmetic results (visual analog scale for cosmesis [VASC]), and costs of the implants.

Results:

Complications: one epidural hematoma in the custom-made group, one delayed failure in precurved group due to wound dehiscence with mesh exposure. There were no infections in either group. All custom-made prostheses perfectly fitted on the defect; eight of 13 precurved mesh prostheses incompletely covered the defect. Custom-made cranioplasty obtained better cosmetic results (average VASC 94 vs. 68), shorter surgical time (141min vs. 186min), and -fewer screws was needed to fix the prostheses in place (6 vs. 15). However, satisfactory results were obtained using precurved mesh in cases of small defects and in single-stage reconstruction. Precurved mesh was found to be cheaper (€1,500 vs. €5,500).

Conclusion:

Custom-made cranioplasty obtained better results and we would suggest that this should be a first choice, particularly for young patients with a large cranial defect. Precurved mesh was cheaper and useful for single-stage resection-reconstruction. Depending on the individual conditions, both prostheses have their place in cranioplasty therapies.

Presentation and short-term evaluation of an all-in-one patient-specific implant for cranial reconstruction: A randomized controlled trial

Cranial reconstruction after bone graft harvesting remains a challenge. A patient-specific implant (PSI) to guide harvesting and reconstruction was evaluated and compared with the use of a free-hand procedure with calcium phosphate cement (C). Patients were randomized to either the PSI or C group. The outcome was measured clinically and radiographically as the primary endpoint. Secondary endpoints were ease of application, patient and surgeon satisfaction, and the complication rate. Twenty patients were randomized to the PSI (n=10) and C (n=10) groups. Two PSI patients were switched to the cement group due to a poor fit of the PSI. There was a non-significant trend towards more successful outcomes in the PSI group. Two PSI patients presented palpable screws, and one cement patient had a palpable dimple. Cone beam computed tomography showed a significantly lower median volume discrepancy in the PSI group (P<0.0001). The total surgical manipulation time was significantly higher in the PSI group. At 10 days postoperative, three PSI and two C patients presented with minor postoperative complications. There was no significant difference in patient or surgeon satisfaction. PSIs are a reliable alternative to cement. This PSI is novel as it also serves as a guide for harvesting the bone blocks required for reconstructive purposes.

Comparative Cost-Effectiveness of Cranioplasty Implants

Purpose

The aim of this study was to compare operative duration and total hospital costs incurred for patients undergoing elective cranioplasty with a variety of materials, including manually shaped autogenous bone graft and titanium mesh, custom patient-specific titanium mesh, polymethyl methacrylate (PMMA) acrylic, and polyetheretherketone (PEEK) implants.

Methods

A single-centre retrospective chart review was used. Patient demographics, defect characteristics, total operative time, and length of hospital stay were obtained. Total costs were sourced from Sunnybrook and standardized to the 2014 to 2015 year. Bivariate and age-controlled multivariate analyses were performed with (n = 119) and without (n = 101) outliers.

Results

When outliers were removed, an age-controlled analysis revealed that autogenous implants resulted in an operative time of 178 ± 37 minutes longer than manually shaped titanium implants (P < .01). The average cost of cranioplasty was CAD$18 335 ± CAD$10 265 for manually shaped titanium implants, CAD$31 956 ± CAD$31 206 for custom patient-specific titanium implants, CAD$20 786 ± CAD$13 075 for PMMA, CAD$14 291 ± CAD$5562 for autogenous implants, and CAD$27 379 ± CAD$4945 for PEEK implants (P = .013). When outliers were removed, cranioplasty with PMMA and PEEK incurred greater costs, CAD$4442 ± CAD$2100 and CAD$13 372 ± CAD$2728, respectively, more than manually shaped titanium implants (P < .01).

Conclusions

Manually shaped titanium mesh is the most cost-effective implant choice for small cranial defects. Large unknown defects and frontal paranasal sinus defects are most effectively treated with autogenous bone or titanium mesh. Despite prolonged operative duration and inpatient admission, total costs were not significantly increased. Both PMMA and PEEK implants were significantly more costly, which may be a result of higher complications necessitating reoperation.

Split Calvarial Grafting for Closure of Large Cranial Defects: The Ideal Option?

Among the various cranioplasty options for reconstruction of large post-craniectomy defects, split calvarial grafting offers numerous significant advantages such as the provision of viable autogenous bone graft material comprising of living, immunocompatible bony cells that integrate fully with the skull bone bordering the cranial defect. Its potential for revascularization and subsequent integration and consolidation allows its successful use even in previously infected or otherwise compromised recipient sites. Its excellent contour match at the recipient site and low cost as compared to various alloplastic implant materials often makes it preferable to the latter. Surgeon's skill, dexterity, expertise and experience are important factors to be considered in this highly technique-sensitive procedure.

Comparison between the different types of heterologous materials used in cranioplasty: a systematic review of the literature

INTRODUCTION

The choice of heterologous materials for cranioplasty after decompressive craniectomy is still difficult. The aim of this study is to examine the association between material of choice and related complications to suggest the best treatment option.

EVIDENCE ACQUISITION

A systematic review was performed for articles reporting cranioplasty comparing the following heterologous implants: titanium, poli-methyl-methacrylate (PMMA), polyetheretherketone (PEEK) and hydroxyapatite (HA). Extracted data included implant materials and incidence of the most frequent complications.

EVIDENCE SYNTHESIS

The final selection resulted in 106 papers but according to our rules only 27 studies were included in the final analysis. Among a total of 1688 custom-made prosthesis implanted, 649 were titanium (38.49%), 298 PMMA (17.56%), 233 PEEK (13.82%), and 508 were HA (30.13%). A total of 348 complications were recorded out of 1688 reported patients (20.64%). In the titanium group, 139 complications were recorded (21.42%); in the PMMA group 57 (19.26%), in the PEEK group 49 (21.03%) and in the HA group 103 (20.3%). If we examine a summary of the reported complications clearly related to cranioplasty (postoperative infections, fractures and prosthesis displacement) versus type of material in multicentric and prospective studies we can see how HA group patients have less reported infections and cranioplasty explantation after infections than PMMA, PEEK and titanium. On the contrary HA patients seem to have a higher number of prosthesis displacement again if compared with the other materials. Since these data are not derived from a statistically correct analysis they should be used only to help to differentiate the properties of the various heterologous cranioplasties.

CONCLUSIONS

The ideal material for all heterologous cranioplasty has not yet been identified. The choice of material should be based on the clinical data of patients, such as the craniectomy size, presence of seizures, possibility of recovery, good long-term outcome associated with a cost analysis.

A Retrospective Comparative Analysis of Titanium Mesh and Custom Implants for Cranioplasty

BACKGROUND

Autologous bone removed during craniectomy is often the material of choice in cranioplasty procedures. However, when the patient's own bone is not appropriate (infection and resorption), an alloplastic graft must be utilized. Common options include titanium mesh and polyetheretherketone (PEEK)-based custom flaps. Often, neurosurgeons must decide whether to use a titanium or custom implant, with limited direction from the literature.

OBJECTIVE

To compare surgical outcomes of synthetic cranioplasties performed with titanium or vs custom implants.

METHODS

Ten-year retrospective comparison of patients undergoing synthetic cranioplasty with titanium or custom implants.

RESULTS

A total of 82 patients were identified for review, 61 (74.4%) receiving titanium cranioplasty and 21 (25.6%) receiving custom implants. Baseline demographics and comorbidities of the 2 groups did not differ significantly, although multiple surgical characteristics did (size of defect, indication for craniotomy) and were controlled for via a 2:1 mesh-to-custom propensity matching scheme in which 36 titanium cranioplasty patients were compared to 18 custom implant patients. The cranioplasty infection rate of the custom group (27.8%) was significantly greater (P = .005) than that of the titanium group (0.0%). None of the other differences in measured complications reached significance. Discomfort, a common cause of reoperation in the titanium group, did not result in reoperation in any of the patients receiving custom implants.

CONCLUSION

Infection rates are higher among patients receiving custom implants compared to those receiving titanium meshes. The latter should be informed of potential postsurgical discomfort, which can be managed nonsurgically and is not associated with return to the operating room.

Evaluation of neurosurgical implant infection rates and associated pathogens: evidence from 1118 postoperative infections

OBJECTIVE

Various implanted materials are used in neurosurgery; however, there remains a lack of pooled data on infection rates (IRs) and infective bacteria over past decades. The goal of this study was to investigate implant infections in neurosurgical procedures in a longitudinal retrospective study and to evaluate the IRs of neurosurgically implanted materials and the distribution of pathogenic microorganisms.

METHODS

A systematic literature search was conducted using PubMed and Web of Science databases for the time period between 1968 and 2018. Neurosurgical implant infections were studied in 5 subgroups, including operations or diseases, implanted materials, bacteria, distribution by country, and time periods, which were obtained from the literature and statistically analyzed. In this meta-analysis, statistical heterogeneity across studies was tested by using p values and I2 values between studies of associated pathogens. Egger’s test was used for assessing symmetries of funnel plots with Stata 11.0 software. Methodological quality was assessed to judge the risk of bias according to the Cochrane Handbook.

RESULTS

A total of 22,971 patients from 227 articles satisfied the study’s eligibility criteria. Of these, 1118 cases of infection were reported, and the overall IR was 4.87%. In this study, the neurosurgical procedures or disorders with the top 3 IRs included craniotomy (IR 6.58%), cranioplasty (IR 5.89%), and motor movement disorders (IR 5.43%). Among 13 implanted materials, the implants with the top 3 IRs included polypropylene-polyester, titanium, and polyetheretherketone (PEEK), which were 8.11%, 8.15%, and 7.31%, respectively. Furthermore, the main causative pathogen was Staphylococcus aureus and the countries with the top 3 IRs were Denmark (IR 11.90%), Korea (IR 10.98%), and Mexico (IR 9.26%). Except for the low IR from 1998 to 2007, the overall implant IR after neurosurgical procedures was on the rise.

CONCLUSIONS

In this study, the main pathogen in neurosurgery was S. aureus, which can provide a certain reference for the clinic. In addition, the IRs of polypropylene-polyester, titanium, and PEEK were higher than other materials, which means that more attention should be paid to them. In short, the total IR was high in neurosurgical implants and should be taken seriously.

Use of Stock Titanium Mesh Plates in Cranioplasty

Craniofacial surgeons are often confronted with major defects of the calvarium. These most commonly are post-traumatic but could also be consequent upon neurosurgical procedures, infection, or tumor removal. There are several options available to reconstruct these defects including autogenous, heterogeneous, and alloplastic material. The goal is to have a method that is easy, cost-effective, with minimal complications, and long-lasting. In our unit we review 100 cases of the use of stock titanium mesh during a 5-year period. Complications occurred in 5 patients (5%) with 3 exposures, 1 late seroma and 1 case requiring repositioning of the plate following trauma. None of the patients required removal of the plate.

Association between metal hypersensitivity and implant failure in patients who underwent titanium cranioplasty

OBJECTIVE

Digitally designed titanium plates are commonly used for the reconstruction of craniofacial defects, although implant exposure (referred to as failure) is one of the major complications. Metal hypersensitivities have been suggested as possible causes of implant failure of orthopedic, intravascular, gynecological, and dental devices, yet there has been no consensus on the requirement for allergy screening before cranioplasty.

METHODS

In this study, the authors prospectively investigated the prevalence of metal hypersensitivity in patients for whom cranioplasty is planned and assess its relationship with titanium implant failure (exposure).

RESULTS

Based on records from 207 included patients, 39.61% of patients showed hypersensitivity to at least one kind of metal. Approximately one-quarter (25.12%) of patients had multiple metal allergies. Co, Cd, and Zn were the 3 most frequently identified metal hypersensitivities. No allergy to titanium was detected in this study. The overall incidence of cranioplasty implant failure was 5.31% (11 of 207). Patients showing hypersensitivities to more than 3 kinds of metal had higher risks of titanium plate exposure.

CONCLUSIONS

Based on their findings, the authors suggest that routine allergy screening be performed before titanium plate cranioplasty. For patients with hypersensitivities to more than 3 metals, alternative materials, such as polyetheretherketone, should be considered for cranioplasty.

Titanium mesh cranioplasty in pediatric patients after decompressive craniectomy: Appropriate timing for pre-schoolers and early school age children

PURPOSE

There is little knowledge on the growth of cranial defects, appropriate timing and outcomes of application of titanium mesh for cranioplasty in the pediatric population, especially pre-school age (2-5 years old) and school age (6-12 years old) children. We hypothesised that cranioplasty for pre-schoolers could be delayed to school age due to the expected cranium growth, whereas, for the school age group, it is better to perform routine cranioplasty (3-6 months) to protect the brain and therefore ensure their timely return to school life.

MATERIALS AND METHODS

A retrospective review of pediatric patients (2-12 years old) who underwent titanium mesh cranioplasty for cranial defects from 2006 to 2012 was performed. Patient demographic data, radiological data, and clinical information were collected. Specifically, cranial defect sizes were evaluated by three-dimensional (3D) reconstruction of computed tomography data after craniectomy, before cranioplasty and 2-years after cranioplasty. Patients were routinely followed up at an outpatient clinic for complications and school attendance.

RESULTS

A total of 18 titanium mesh cranioplasties were performed in 18 patients. The average interval between craniectomy and cranioplasty was 3 years for pre-schoolers and 4 months for the school age group. Patients in the pre-schooler group showed significant enlargements in cranial defects during the interval as compared with the school age group (26% vs. 4%, P < 0.05). There were no surgery-related complications except in one patient, who had titanium mesh exposure 11 months later. Two years after cranioplasty, there was no significant difference in mild cranial defect enlargements between the two groups (11% vs. 6%, P > 0.05). Patients were followed for an average of 5 (range, 2-8) years. All patients had satisfactory recovery of cranial contour, sufficient protection of the brain and active participation in school study. All patients had satisfactory recovery of cranial contour, sufficient protection of the brain and active participation in school.

CONCLUSION

Timing of titanium mesh cranioplasty after decompressive craniectomy based on their age is a workable solution for school-age pediatric patients. The enlargement of cranium defects in pre-schoolers supports a delayed repair until school age. The long-term outcomes for these patients with titanium mesh cranioplasty are favourable.

Long-Term Complications of Cranioplasty Using Stored Autologous Bone Graft, Three-Dimensional Polymethyl Methacrylate, or Titanium Mesh After Decompressive Craniectomy: A Single-Center Experience After 596 Procedures

OBJECTIVE

Cranioplasty is a technically simple procedure intended to repair defects of the skull to provide protection after craniectomy, improve functional outcomes, and restore cosmesis. Several materials have been used for the restoration of skull defects, including autologous bone grafts (AGs), polymethyl methacrylate (PMMA) flaps, and titanium mesh (T-mesh). However, the long-term results of cranioplasty after use of these materials are controversial.

METHODS

Medical records of 596 patients who underwent cranioplasty at our medical center between 2009 and 2015 with at least 2.5 years of follow-up were retrospectively reviewed. Patients were classified into 3 groups according to the materials used: AG, three-dimensional PMMA, and T-mesh. Demographic and clinical characteristics and postoperative complications were analyzed.

RESULTS

Cranioplasty with AG had the highest bone flap depression rate (4.9%; P = 0.02) and was associated with a 26% long-term bone flap resorption. Younger age was a risk factor for bone flap resorption. T-mesh had a higher risk of postoperative skin erosion and bone exposure (17%; P = 0.004). Patients with diabetes, previous craniotomy, or hydrocephalus showed a higher risk of postoperative skin erosion. PMMA was associated with the highest rate of postoperative infection (14.4% <3 months, 28.1% >3 months; P < 0.05), and previous craniotomy may increase the infection risk after cranioplasty with PMMA.

CONCLUSIONS

Complications after cranioplasty are high, and the various types of cranioplasty materials used are associated with different complications. Surgeons need to be aware of these potential complications and should choose the appropriate material for each individual patient.

Reconstruction of Acquired Frontal Bone Defects Using Titanium Mesh Implants: A Retrospective Study

PURPOSE

Frontal bone deformities can be acquired due to trauma or ablative tumor resection surgeries and osteomyelitis. It may also occur due to congenital malformations. Repair of these defects have long been a challenge to oral and maxillofacial surgeons. We report our experience in the reconstruction of acquired frontal bone defects by titanium mesh implant.

PATIENTS AND METHODS

Titanium mesh was used for reconstruction in 35 patients (18-55 years age-group) (34 males and 01 females) of acquired frontal bone defects secondary to trauma (RTA). All these patients have been referred to author by Department of Neurosurgery of the institute of Affiliation.

RESULTS

All these cases acquired defects as a result of trauma. Follow-up ranged from 12 to 18 months after the reconstruction. Patients were followed up for the progress of healing, stability of implants, infection, wound dehiscence, discharging sinus, exposure of implants, collections, patient satisfaction regarding esthetics and reaction to thermal changes. No postoperative complications were found.

CONCLUSION

In reconstruction of frontal bone defects, titanium mesh gives satisfactory results.

Staged reconstruction of large skull defects with soft tissue infection after craniectomy using free flap and cranioplasty with a custom-made titanium mesh constructed by 3D-CT-guided 3D printing technology: Two case reports

RATIONALE

A craniectomy, which results in a large skull defect, is performed to decrease the intracranial pressure under conditions such as intracranial hemorrhage and ischemic stroke. When the patient's condition is stabilized, autologous cranioplasty using the bone flap previously removed in the craniectomy is performed. Bone flap infection after the autologous cranioplasty is not uncommon and is difficult to treat. After the infection is controlled, cranioplasty is needed to improve the head deformity and neurologic function. Cranioplasty with a titanium mesh can result in aesthetic improvement and a low infection rate. Using 3-dimensional computed tomography (3D-CT) and 3D printing, titanium mesh is manufactured to fit perfectly on the patient's skull defect.

PATIENT CONCERNS

Two patients with large skull defects in the right temple area due to previous craniectomy were referred to our department for reconstruction. They had histories of recurrent infections at the operation site even after removal of the autologous bone flap that had been used for the cranioplasty.

DIAGNOSIS

Preoperative computed tomography (CT) showed 12×16 cm and 8×8.3 cm skull defect on right temporal area, respectively.

INTERVENTIONS AND OUTCOME

The infection was controlled by well-vascularized free flap coverage. After the surgery, cranioplasty with custom-made titanium mesh was performed to improve the aesthetic and functional problems of the patients. The contour of the temporal area was symmetric. The patients were satisfied with the results.

LESSONS

Staged reconstruction of large skull defects with soft tissue infection after craniectomy using free flap followed by cranioplasty with titanium mesh on can lead to safe, aesthetic, and satisfactory result.

Muscle Forehead Flap: Salvage Surgery for Closure of Cutaneous Fistula After Cranioplasty Exposure

BACKGROUND

Infection and skin fistula are well-known complications after cranioplasty leading to reconstruction exposure and usually requiring new surgical procedure with poor condition for cutaneous closure. We describe 2 cases using muscle forehead flap (MFF) to treat skin fistula and cranioplasty exposure.

CASE DESCRIPTION

The first case was a 43-year-old man who underwent a calvarial bone graft of the frontal sinus anterior wall after craniofacial trauma. Three months postoperatively, osteitis of the bone reconstruction and a skin fistula occurred in the median frontal region. The second case was a 37-year-old woman treated for a cingular glioblastoma by 3 surgeries, concomitant chemoradiation therapy, and frontal reconstruction using a titanium plate. She presented a plate exposure associated with cerebrospinal fluid leak and meningitis. Both patients were successfully treated by surgical removal of the frontal cranioplasty and skin closure using MFF. We observed a satisfying cosmetic result with no recurrence of infection or fistula at 12 and 4 months, respectively.

CONCLUSIONS

MFF is a surgical option to treat complex cases of cutaneous fistula secondary to cranioplasty exposure of the anterior cranial fossa.

Complications of Cranioplasty

Cranioplasty is a time-honoured surgical procedure to restore the calvarial form and function that is associated with a relatively high complication rate. The present article analyzed various complications and reviewed the complications based on study of the relevant research in the craniofacial literature. Complications were broadly divided into 2 groups, intraoperative and postoperative, for ease of understanding. The etiological factors, local and systemic condition of the patient, prevention, and management of various complications were widely discussed. The article also highlighted problems and complications associated with various reconstructive materials. Insights into various complications of cranioplasty enable surgeon to understand them better, minimize the chances of occurrence, and improve surgical outcome. In spite of reported high rate of complications, serious complications like meningitis, air embolism, and death are rare.

Infection burden and immunological responses are equivalent for polymeric and metallic implant materials in vitro and in a murine model of fracture-related infection

The development of an infection is a major complication for some patients with implanted biomaterials. Whether the material or surface composition of the used biomaterial influences infection has not been directly compared for key biomaterials currently in use in human patients. We conducted a thorough in vitro and in vivo investigation using titanium (Ti) and polyether-ether-ketone (PEEK) as both commercially available and as modified equivalents (surface polished Ti, and oxygen plasma treated PEEK). Complement activation and cytokine secretion of cell of the immune system was assessed in vitro for all materials in the absence and presence of bacterial stimulants. In a follow-up in vivo study, we monitored bacterial infection associated with clinically available and standard Ti and PEEK inoculated with Staphylococcus aureus. Complement activation was affected by material choice in the absence of bacterial stimulation, although the material based differences were largely lost upon bacterial stimulation. In the in vivo study, the bacterial burden, histological response and cytokine secretion suggests that there is no significant difference between both PEEK and Ti. In conclusion, the underlying material has a certain impact in the absence of bacterial stimulation, however, in the presence of bacterial stimulation, bacteria seem to dictate the responses in a manner that overshadows the influence of material surface properties. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 1095-1106, 2019.

Adhesion sutures for seroma reduction in cranial reconstructions with polymethyl methacrylate prosthesis in patients undergoing decompressive craniectomy: A clinical trial

Background:

Cranial reconstruction with polymethyl methacrylate (PMMA) prosthesis is used for calvarial defects secondary to decompressive craniectomies. Seroma is one of the most frequent complications of this procedure and can lead to the dehiscence, extrusion, infection, and loss of the prosthesis. The objective of the study is to analyze the effectiveness of the tacking sutures between the prosthesis and the scalp flap in reducing the seroma.

Methods:

This is a prospective study with 63 patients submitted to cranioplasty between 2014 and 2017 for defects resulting from decompressive craniectomies. All patients were followed up postoperatively for at least 3 months and the diagnosis of seroma was made clinically. In the first 22 patients, the conventional technique was applied and, in the following 41, the technique with tacking sutures was used. The incidence of seroma was collected for both groups.

Results:

The overall incidence of seroma was 65.1%. Compared to the conventional technique, the use of tacking sutures was associated with a statistically significant reduction in the incidence of seroma from 90.9% to 51.2% (P = 0.002).

Conclusion:

The use of the tacking sutures in cranioplasties with PMMA prosthesis reduced the incidence of seroma postoperatively.