Custom-made Porous Hydroxyapatite Research Articles

Long-Term Follow-Up of Custom-Made Porous Hydroxyapatite Cranioplasties: Analysis of Infections in Adult and Pediatric Patients.

In neurosurgery, cranioplasty (CP) stands as a pivotal surgical intervention, particularly following head trauma or various neurosurgical interventions. This study scrutinizes the intricacies of CP, emphasizing its prevalence and associated complications, with a specific focus on custom-made porous hydroxyapatite (PHA) implants. The investigation spans 687 patients (with 80 patients of pediatric age, less than 14 years old) across 26 neurosurgical centers in five European countries. Methodologically, this study delves into patient characteristics, complications, and infection data through a comprehensive post-marketing on-site surveillance approach. Notably, infections emerged as the primary complication, affecting 41 patients (6% of implants) with a clear distinction in onset patterns between pediatric (with more infections, 10% versus 5.4% in adults and an earlier onset of complications) and adult populations. Out of these 41 cases, cranioplasty explantation was required in 30 patients, 4.4% of the total population. Furthermore, bifrontal decompression correlated with a significantly elevated infection risk as compared to unilateral decompression (12.5% versus 5.1%) which remains after the examination of possible confounding factors. These findings provide substantial insights into the complexities of CP, suggesting the necessity for tailored strategies in pediatric and adult cases and cautioning against bifrontal decompressions. Despite acknowledging limitations and calling for prospective studies with long term follow-up, this research advances our understanding of the use of PHA CP, guiding clinical decision-making and emphasizing the importance of customized approaches for diverse patient cohorts.

Predictors of postoperative epidural hematomas after custom-made porous hydroxyapatite cranioplasty: a single-center experience of 194 consecutive cases.

Cranioplasty is important for improving cosmesis and functional recovery after decompressive craniectomy. We assessed the incidence and predictors of post-cranioplasty epidural hematomas requiring surgical evacuation. A single-institution, retrospective study enrolled 194 consecutive patients who underwent a cranioplasty using custom-made hydroxyapatite between February 2008 and April 2022. Variables associated with postoperative epidural hematoma requiring surgical evacuation at the p < 0.1 level in unadjusted analysis were entered into multivariable analyses. Nine patients (4.6%) experienced postoperative epidural hematomas requiring evacuation, with time interval between craniectomy and cranioplasty <6 months (adjusted odds ratio (aOR), 20.75, p = 0.047), cranioplasty-to-bone shift > half of the bone thickness (aOR, 17.53, p = 0.008), >10 mm difference between pre-cranioplasty and post-cranioplasty midline brain shift contralateral to the cranioplasty (aOR, 17.26, p < 0.001), and non-resorbable duraplasty (aOR, 17.43, p = 0.011) identified as independent predictors. Seventeen patients (8.8%) experienced post-cranioplasty hydrocephalus requiring shunt placement. Twenty-six patients (13.4%) experienced postoperative infection. Sixteen patients (8.2%) had postoperative epileptic seizures. The identification of independent predictors of post-cranioplasty epidural hematomas requiring surgical evacuation will help identify at-risk patients, guide prophylactic care, and reduce morbidity of this common and important procedure.

Long-term follow-up of custom-made porous hydroxyapatite cranioplasty in adult patients: a multicenter European study. Can we trust self-reported complications?

Cranioplasty is a surgical intervention aiming to re-establish the integrity of skull defects. Autologous bone and different heterologous materials are used for this purpose, with various reported related complications. The aim of the study was to evaluate the complication rate in a multicentric cohort of patients underwent porous hydroxyapatite (PHA) cranioplasty implantation and to assess the validity of company post-market clinical analysis. Authors analyzed a company-based register of 6279 PHA cranioplasty implanted all over the world. In these adult patients only self-reported complications were available. We then obtained the data of adult patients treated with custom-made porous HA prostheses (CustomBone Service) in 20 institutions from different European countries through an on-site interview with the physicians in charge of the patients (N.=494). The endpoints were the incidence of adverse events and of related implant removal. The groups of patients had similar demographics characteristics. The average follow-up was 26.7 months. A significantly higher number of complications was recorded in the group of patients underwent on-site interview. Thirty-nine complications were reported (7.89%) with an explantation rate of 4.25% (21 cases) in the series, compared to the data reported from the Company (complications rate of 3.3% and explantation rate of 3.1%). The most common complications were infection (4.86%), hematomas (1.22%), fractures (1.01%), mobilization (0.4%) and scar retraction (0.4%). Our data confirm that porous HA cranioplasty is at least as effective as other heterologous materials to repair cranial defects. Another interesting finding is that self-reporting complications by surgeons does not give a precise picture of the real rate of complications of the devices. These data in future studies need to be re-confirmed with on-site interviews.

Custom-Made Porous Hydroxyapatite Cranioplasty in Patients with Tumor Versus Traumatic Brain Injury: A Single-Center Case Series

Cranioplasty is a common neurosurgical procedure with the goal of restoring skull integrity. Custom-made porous hydroxyapatite prostheses have long been used for cranial reconstruction in patients with traumatic brain injury. We present a large consecutive series of 2 groups of patients undergoing cranioplasty with hydroxyapatite custom bone and compare the adverse events (AEs) between the 2 groups. We examined a series of consecutive patients who underwent cranioplasty using custom-made porous hydroxyapatite implants following tumor resection and traumatic brain injury at a single center between March 2003 and May 2018. The implants were designed and produced according to the surgeon's specifications and based on the patient's computed tomography scan data obtained through a standardized protocol. AEs were recorded. Information on 38 patients with tumor and 39 patients with traumatic brain injury was collected and analyzed. A significant difference in the timing of surgery was found between the 2 groups; single-stage surgery was performed in 84% of patients in the tumor versus 8% of those in the traumatic brain injury group (P < 0.0001). The rate of AEs was not significantly different between the 2 groups (P= 0.4309) and was not related to the timing of surgery. Custom-made hydroxyapatite cranioplasty is a solution for cranial reconstruction in patients with cranial tumors. The low incidence of AEs in a consecutive series of patients with either trauma or tumors demonstrates that these prostheses represent a safe solution independent of the characteristics of cases.

Hydroxyapatite ceramic implants for cranioplasty in children: a retrospective evaluation of clinical outcome and osteointegration.

Cranioplasty in children is a controversial and challenging issue, since there is still no consensus on the ideal material. Main problems in paediatric age are represented by the child's growing skull, the lower bone thickness and the high incidence of cerebrospinal fluid (CSF) disorders or brain swelling. Autologous bone is still considered the "gold standard". When it is not available, a wide range of alloplastic materials have been proposed. Hydroxyapatite, a ceramic-based derivative, bears a chemical composition very similar to the human natural bone, making this material a valuable alternative to other cranioplasty solutions. All patients implanted with a custom-made porous hydroxyapatite device at Santobono-Pausilipon Hospital in Naples were retrospectively reviewed. A follow-up CT scan of the skull was performed from 1 up to 48months postoperatively to document the bone ingrowth as well as the osteointegration process. The bone density was measured as according to the Hounsfield scale at the bone-implant interface. Between 2014 and 2018, 11 patients (7 males, 4 females) underwent cranioplasty with hydroxyapatite ceramic implants (HAP). Patients' age ranged between 3 and 16years old. Initial aetiology was trauma in most cases. Two subjects were implanted with HAP as primary cranioplasty, 9 as revision surgery following previous cranioplasty failure. Sites of the cranial defect were unilateral fronto-temporo-parietal (N= 8), unilateral frontal (N= 1) and bifrontal (N= 2). Two patients with large bilateral defects received two prostheses. In one of these, the two prostheses were explanted and replaced with two back-up implants (accounting for a total of 15 implants in 11 patients). Osteointegration was measurable for 12 out of 15 implanted devices. The mean percentage was about 51%. There were six asymptomatic prosthesis fractures (40%), all occurring within 6months from implant. In one case, the bifrontal prostheses were explanted and replaced. This was the only patient who underwent revision surgery. Hydroxyapatite ceramic implants represent a valid alternative to other cranioplasty solutions. Where coaptation occurs correctly, with good osteointegration, implant mechanical resistance increases over time.

Cranioplasty after craniectomy in pediatric patients-a systematic review.

Complications following cranioplasty with either autografts or cranial implants are commonly reported in pediatric patients. However, data regarding cranioplasty strategies, complications and long-term outcomes are not well described. This study systematically reviews the literature for an overview of current cranioplasty practice in children. A systematic review of articles published from inception to July 2018 was performed. Studies were included if they reported the specific use of cranioplasty materials following craniectomy in patients younger than 18 years of age, and had a minimum follow-up of at least 1 year. Twenty-four manuscripts, describing a total of 864 cranioplasty procedures, met the inclusion criteria. The age of patients in this aggregate ranged from 1 month to 20 years and the weighted average was 8.0 years. The follow-up ranged from 0.4 months to 18 years and had a weighted average of 40.4 months. Autologous bone grafts were used in 484 cases (56.0%). Resorption, infection and/or hydrocephalus were the most frequently mentioned complications. In this aggregate group, 61 patients needed a revision cranioplasty. However, in 6/13 (46%) papers studying autologous cranioplasties, no data was provided on resorption, infection and revision cranioplasty rates. Cranial implants were used in 380 cases (44.0%), with custom-made porous hydroxyapatite being the most commonly used material (100/380, 26.3%). Infection and migration/fracturing/loosening were the most frequently documented complications. Eleven revision cranioplasties were reported. Again, no data was reported on infection and revision cranioplasty rates, in 7/16 (44%) and 9/16 (56%) of papers, respectively. Our systematic review illuminates that whether autografts or cranial implants are used, postcranioplasty complications are quite common. Beyond this, the existing literature does not contain well documented and comparable outcome parameters, suggesting that prospective, long-term multicenter cohort studies are needed to be able to optimize cranioplasty strategies in children who will undergo cranioplasty following craniectomy.

Independent Factors Affecting Postoperative Complication Rates After Custom-Made Porous Hydroxyapatite Cranioplasty: A Single-Center Review of 109 Cases

Cranioplasties are an important neurosurgical procedure not only for improved cosmesis but also for improved functional recovery after craniectomy with a large cranial defect. The aim of this study was to identify predictive factors of postcranioplasty complications using custom-made porous hydroxyapatite cranioplasty. Retrospective review was performed of all patients who underwent a reconstructive cranioplasty using custom-made hydroxyapatite at our institution between February 2008 and September 2017. Postoperative complications considered included bacterial infection, seizures, hydrocephalus requiring ventricular shunt placement, and cranioplasty-to-bone shift. Variables associated at P < 0.1 level in unadjusted analysis were entered into backward stepwise logistic regression models. Of 109 patients included, 15 (13.8%) experienced postoperative infection, with craniectomy performed at an outside institution (adjusted odds ratio [OR] 10.37 [95% confidence interval [CI], 2.03-75.27], P= 0.012) and a previous infection at the surgical site (adjusted OR 6.15 [95%CI, 1.90-19.92], P= 0.003) identified as independent predictors. Six patients (5.5%) experienced postoperative seizures, with stroke (ischemic and hemorrhagic) as a reason for craniectomy (adjusted OR 11.68 [95% CI, 2.56-24.13], P < 0.001) and the presence of seizures in the month before cranioplasty (adjusted OR 9.39 [95% CI, 2.04-127.67], P= 0.002) identified as independent predictors. Four patients (3.7%) experienced postcranioplasty hydrocephalus necessitating shunt placement, and 5 patients (4.6%) experienced cranioplasty-to-bone shift ≥5 mm, but no significant predictive factors were identified for either complication. This study identified possible predictive factors for postcranioplasty complications to help identify at-risk patients, guide prophylactic care, and improve morbidity of this important surgical procedure.

Design of Custom-Made Porous Hydroxyapatite Devices for the Reconstruction of the Skull: A 6-Year Multicentric Experience:

Design of Custom-Made Porous Hydroxyapatite Devices for the Reconstruction of the Skull: A 6-Year Multicentric Experience:

Histological assessment of porous custom-made hydroxyapatite implants 6 months and 2.5 years after cranioplasty.

Background:In cranial reconstruction, the features of artificial bone differ. Custom-made porous hydroxyapatite (HAp) implants for cranioplasty have been used all over the world because of their good cosmetic, biocompatibility, and osteoconductive properties. Surgical techniques were analyzed, and histological assessment of new bone formation in the hydroxyapatite was performed.Methods:Over a 6-year time period, 41 patients underwent cranioplasty using a custom-made three-dimensional hybrid pore structured hydroxyapatite (3DHPoHAp) implant. The surgical techniques and histological evaluations of 3DHPoHAp in 2 cases, removed 6 months and 2.5 years after cranioplasty, are described.Results:Using 3DHPoHAp, cranioplasty was successfully performed for all patients. The implant fit the bone defect exactly, and surgical manoeuvres were simple and easy. All implants were firmly fixed using a titanium plate, and postoperative infection occurred in 1 patient (2.4%). New bone formation was seen in 2 cases 6 months and 2.5 years after cranioplasty. Osteoblasts were progressing to the stoma at various depths, and bone tissue had ripened. Furthermore, lamellar structure was observed in the case at 2.5 years.Conclusions:In this study, there was a low infection rate, and new bone formation was seen in vivo after cranioplasty. This study also demonstrated that the 3DHPoHAp implant is a good candidate for cranial bone implants because its good osteoconductivity and biocompatibility.

Osteointegration in Cranial Bone Reconstruction: A Goal to Achieve

The number of cranioplasty procedures is steadily increasing, mainly due to growing indications for decompressive procedures following trauma, tumor or malformations. Although autologous bone is still considered the gold standard for bone replacement in skull, there is an urgent need for synthetic porous implants able to guide bone regeneration and stable reconstruction of the defect. In this respect, hydroxyapatite scaffolds with highly porous architecture are very promising materials, due to the excellent biocompatibility and intrinsic osteogenic and osteoconductive properties that enable deep bone penetration in the scaffold and excellent osteointegration. Osteointegration is here highlighted as a key aspect for the early recovery of bone-like biomechanical performance, for which custom-made porous hydroxyapatite scaffolds play a major role. There are still very few cases documenting the clinical performance of porous scaffolds following cranioplasty. This paper reports 2 clinical cases where large cranial defects were repaired by the aid of porous hydroxyapatite scaffolds with customized shapes and 3D profiles (Fin-Ceramica, Faenza, Italy). In the long term (i.e., after 2 years), these scaffolds yielded extensive osteointegration through formation and penetration of new organized bone. These results confirm that porous hydroxyapatite scaffolds, uniquely possessing chemico-physical and morphological/mechanical properties very close to those of bone, can be considered as a tool to provide effective bone regeneration in large cranial bone defects. Moreover, they may potentially prevent most of the postsurgical drawbacks related to the use of metal or plastic implants.

Soft tissue expansion and cranioplasty: For which indications?

The aim of this study was to better define indications for scalp tissue expansion before cranioplasty, and to describe our methodology for calculate the surface of tissue needed, by combining a preoperative analysis of both the size of the defect and the quality of skin above. A retrospective analysis of patients who underwent expansion before cranioplasty between 2009 and 2015 was conducted. Information was collected on the etiology, size and location of the defect, and reasons of skin contracture. Data concerning expansion and cranioplasty were reviewed. Among 47 patients who underwent operation for cranioplasty, five (10.6%) required previous scalp tissue expansion. The etiology of the bone defect was tumoral in three cases, posttraumatic in one case, and a decompressive craniectomy in one case. The mean surface of the bone defect was 69.6 ± 18.7 cm(2). The locations of the defects were fronto-temporo-parietal, frontal, temporo-frontal, on the vertex, and occipital. The cause associated with the skin contracture was an infection in four cases and a delayed cranioplasty in one case. A round-profile expander and a custom-made porous hydroxyapatite implant were used for all patients. The accurate assessment of tissue needed before cranioplasty is as essential as the choice of the material used for bone reconstruction. After previous infected cranioplasty or delayed reconstruction of large defects, scalp tissue expansion should be proposed.

The efficacy of custom-made porous hydroxyapatite prostheses for cranioplasty: evaluation of postmarketing data on 2697 patients.

Cranioplasty is a surgical intervention aimed at reestablishing the integrity of skull defects. Autologous bone is still considered the treatment of choice for cranioplasty. The aims of this study were to characterize and evaluate the efficacy of porous hydroxyapatite (HA) to fill skull defects based on its biomimetic characteristics. The authors analyzed the postmarketing data of all patients treated with custom-made porous HA prostheses (CustomBone Service). Characterization data in terms of physicochemical analysis and mechanical performance of the porous HA prostheses were also reported. The low incidence of adverse events (5.72%) due to the use of HA porous custom-made prostheses for cranioplasty is related to the biomimetic performance of the prostheses. The composition and morphology of the porosity enable it to be a useful biomimetic prosthesis for the reconstruction of large and complex skull defects, also able to promote osteointegration. These collected and analyzed data demonstrate that porous HA is a suitable material to produce custom-made prostheses to repair craniolacunia. It is a biomimetic implant well-tolerated in both adult and pediatric patients and has been shown to be an effective and good alternative for cranial reconstruction.

Spontaneous fractures in custom-made porous hydroxyapatite cranioplasty implants: is fragility the only culprit?

Although the porous hydroxyapatite (PHA) used in custom-made cranioplasty implants is a material appreciated for its biomimetic properties, before osteointegration it is initially very fragile. Nevertheless, we wondered whether this primary fragility is entirely due to brittleness or whether the surgeon's actions may influence the behavior of the material. To study the influence of the surgeon's behavior, we made a virtual model of a custom-made PHA cranioplasty implant and submitted it to three implant procedural variables using finite element methods. In the first test, a scenario in which the surgeon's design, validation, and positioning techniques are impeccable, the edges of the implant adhered well to the craniectomy margins. In the second test, a discrepancy between a portion of the perimeter of the craniectomy and the profile of the prosthesis was modeled, and in the third test, several gaps were simulated between the implant and the craniectomy margins. Our mathematical model showed that when local and general discontinuities were included in the test scenarios, there was an increase in the load coming to bear on the cranioplasty implant, which amounted to 80 and 50 %, respectively. The fragility of custom-made PHA cranioplasty implants increases if the surgeon fails to achieve a precise design and validation, and/or an accurate surgical procedure. Nevertheless, careful attention during these phases helps to maintain the strength of the implant, given the more favorable mechanical conditions, without interfering with its biomimetic capacity.

Surgical pitfalls with custom-made porous hydroxyapatite cranial implants

Aim: Cranioplasty implants are used primarily in cases of surgical cranial decompression following pathological elevations of intracranial pressure. Available bone substitutes include porous hydroxyapatite (HA) and polymethylmethacrylate. Whichever material is used, however, prosthetic cranial implants are susceptible to intra- and postsurgical complications and even failure. The aim of this study was to investigate such occurrences in HA cranioplasty implants, seeking not only to determine the likely causes (whether correlated or not with the device itself) but also, where possible, to suggest countermeasures. Methods: We analyzed information regarding failures or complications reported in postmarketing surveillance and clinical studies of patients treated worldwide with custom-made HA cranial implants (Custom Bone Service Fin-Ceramica Faenza, Italy) in the period 1997-2013. Results: The two most common complications were implant fractures (84 cases, 2.9% of the total fitted) and infections (51 cases, 1.77%). Conclusion: Although cranioplasties are superficial and not difficult types of surgery, and use of custom-made implants are often considered the easy option from a surgical perspective, these procedures are nonetheless plagued by potential pitfalls. If performed well they yield more than satisfactory results from the points of view of both the patient and surgeon, but lack of appropriate care can open the door to numerous potential sources of failure, which can compromise-even irreparably-the ability to heal.

Enhancing dermal and bone regeneration in calvarial defect surgery.

Introduction:To optimize the functional and esthetic result of cranioplasty, it is necessary to choose appropriate materials and take steps to preserve and support tissue vitality. As far as materials are concerned, custom-made porous hydroxyapatite implants are biomimetic, and therefore, provide good biological interaction and biointegration. However, before it is fully integrated, this material has relatively low mechanical resistance. Therefore, to reduce the risk of postoperative implant fracture, it would be desirable to accelerate regeneration of the tissues around and within the graft.Objectives:The objective was to determine whether integrating growth-factor-rich platelet gel or supportive dermal matrix into hydroxyapatite implant cranioplasty can accelerate bone remodeling and promote soft tissue regeneration, respectively.Materials and Methods:The investigation was performed on cranioplasty patients fitted with hydroxyapatite cranial implants between 2004 and 2010. In 7 patients, platelet gel was applied to the bone/prosthesis interface during surgery, and in a further 5 patients, characterized by thin, hypotrophic skin coverage of the cranial lacuna, a sheet of dermal matrix was applied between the prosthesis and the overlying soft tissue. In several of the former groups, platelet gel mixed with hydroxyapatite granules was used to fill small gaps between the skull and the implant. To confirm osteointegration, cranial computed tomography (CT) scans were taken at 3-6 month intervals for 1-year, and magnetic resonance imaging (MRI) was used to confirm dermal integrity.Results:Clinical examination performed a few weeks after surgery revealed good dermal regeneration, with thicker, healthier skin, apparently with a better blood supply, which was confirmed by MRI at 3-6 months. Furthermore, at 3-6 months, CT showed good biomimetism of the porous hydroxyapatite scaffold. Locations at which platelet gel and hydroxyapatite granules were used to fill gaps between the implant and skull appeared to show more rapid integration of the implant than untreated areas. Results were stable at 1-year and remain so to date in cases where follow-up is still ongoing.Conclusions:Bone remodeling time could be reduced by platelet gel application during cranioplasty with porous hydroxyapatite implants. Likewise, layering dermal matrix over such implants appears to promote dermal tissue regeneration and the oshtemo mimetic process. Both of these strategies may, therefore, reduce the likelihood of postsurgical fracture by promoting mechanical resistance.

Use of "custom made" porous hydroxyapatite implants for cranioplasty: postoperative analysis of complications in 1549 patients

Background:Cranioplasty is a surgical intervention aimed at reestablishing the integrity of skull defects, and should be considered the conclusion of a surgical act that began with bone flap removal. Autologous bone is still considered the treatment of choice for cranioplasty. An alternative choice is bioceramic porous hydroxyapatite (HA) as it is one of the materials that meets and comes closest to the biomimetic characteristics of bone.Methods:The authors analyzed the clinical charts, compiled by the neurosurgeon, of all patients treated with custom-made porous HA devices (Custom Bone Service Fin-Ceramica, Faenza) from which epidemiological and pathological data as well as material-related complications were extrapolated.Results:From November 1997 to December 2010, 1549 patients underwent cranioplasty with the implantation of 1608 custom-made porous HA devices. HA was used in 53.8% of patients for decompressive craniectomy after trauma or intracranial hemorrhage, while the remaining cases were for treated for comminuted fracture, cutaneous or osseous resection, cranial malformation, autologous bone reabsorption or infection or rejection of previously implanted material. The incidence of adverse events in patients treated for cranioplasty, as first line treatment was 4.78% (56 events/1171 patients), and 5.02%, (19 events/378 patients) at second line.Conclusion:This study demonstrates that HA is a safe and effective material, is well tolerated in both adult and pediatric patients, and meets the requirements necessary to repair craniolacunia.