Cranioplasty Material Research Articles

УЛЬТРАСТРУКТУРНЫЕ ИЗМЕНЕНИЯ В ТВЕРДОЙ МОЗГОВОЙ ОБОЛОЧКЕ ПОСЛЕ КРАНИОПЛАСТИЧЕСКИХ ОПЕРАЦИЙ

Background. Performing cranioplasty is a method of treating trepanated syndrome. Modern cranioplastic material should be biocompatible and does not cause inflammatory changes in the adjacent membranes of the brain. Aim of the research. To study ultrastructural changes in the dura mater after cranial trepanation, after plasty of the skull defect with a titanium plate "Medbiotech" and material "Superfluvis" and compare with an intact meninges. Material and methods. Rabbits underwent experimental skull trepanation (group "control"), plastic closure of the trepanation defect with titanium (group "titanium"), material "Superfluvis" (group "experience"). The "intact" group consisted of rabbits without surgery. The thickness of the dura mater and ultrastructural changes in it were studied. Results. The average thickness of the dura mater when using the "Superfluvis" material in cranioplasty was 2.74 times (p=0.005) higher than the intact one, but its thickness was 1.66 times (p=0.008) and 1.39 times (p=0.005) less in comparison with the "titan" and "control" groups, respectively. Conclusions. Cranioplasty of the trepanation defect of the rabbit skull with a material separating the dura mater from the soft tissues of the head reduces the degree of hyperplasia of fibrous tissue in this shell. The use of the "Superfluvis" material to close the defect of the rabbit skull causes less pronounced fibrosis of the TMO subject, and also contributes to greater preservation of the structure of the layer of boundary dural cells than when using a titanium plate for the same purpose.

Cranial Repair in Children: Techniques, Materials, and Peculiar Issues.

Cranial repair in children deserves particular attention since many issues are still controversial. Furthermore, literature data offer a confused picture of outcome of cranioplasty, in terms of results and complication rates, with studies showing inadequate follow-up and including populations that are not homogeneous by age of the patients, etiology, and size of the bone defect.Indeed, age has merged in the last years as a risk factor for resorption of autologous bone flap that is still the most frequent complication in cranial repair after decompressive craniectomy.Age-related factors play a role also when alloplastic materials are used. In fact, the implantation of alloplastic materials is limited by skull growth under 7years of age and is contraindicated in the first years if life. Thus, the absence of an ideal material for cranioplasty is even more evident in children with a steady risk of complications through the entire life of the patient that is usually much longer than surgical follow-up.As a result, specific techniques should be adopted according to the age of the patient and etiology of the defect, aiming to repair the skull and respect its residual growth.Thus, autologous bone still represents the best option for cranial repair, though limitations exist. As an alternative, biomimetic materials should ideally warrant the possibility to overcome the limits of other inert alloplastic materials by favoring osteointegration or osteoinduction or both.On these grounds, this paper aims to offer a thorough overview of techniques, materials, and peculiar issues of cranial repair in children.

Manufacturing Process of Low‐Contamination Titanium Foam as Implant Material for Cranioplasty Based on Replica Technique

The article investigates the development of a manufacturing route for highly porous titanium foams suitable for craniofacial surgery applications, particularly in cranioplasties. The study focuses on the polyurethane replication method for foam production and emphasizes reducing residual gas content, as it significantly affects the mechanical properties and suitability for approval of the foams. Various factors such as starting materials, solvent debinding, heating schedules, and hydrogen atmosphere are analyzed for their impact on residual gas content. It is shown that significant reductions in residual gas content can only be achieved by reworking each step of the process. A combination of initial solvent debinding of the PU template with dimethyl sulphoxide, reduction of suspension additives, use of coarser Gd. 1 powders, and an integrated debinding and sintering process under partial hydrogen atmosphere achieves a significant reduction in residual gas content. This way, the potential for producing titanium foams that comply with relevant standards for craniofacial implants is demonstrated.

Computer-guided cranioplasty using ultra-high molecular weight polyethylene patient-specific implants: a case series

IntroductionCranioplasty is the surgical correction of a cranial defect. Three-dimensional software designs have allowed patient-specific single-step cranial reconstruction for neuroprotection and cosmesis. Ultra-high molecular weight polyethylene for partial or total bone replacement has been recently introduced as a promising material for cranioplasty. The objectives of this study are to evaluate the complications and esthetic results concerning the use of ultra-high molecular weight polyethylene patient-specific implants in craniectomy patients.MethodsWe report a series of nine patients with cranial defects from a previous craniectomy, or patients eligible for simultaneous craniectomy and cranioplasty via computer designed ultra-high molecular weight polyethylene patient-specific implants. We have analyzed the complications and cosmetic outcomes over a course of six months.ResultsNone of the cases developed infection, extra/subdural hematoma, cerebrospinal fluid leak, or implant failure. Three cases had postoperative sequalae: The first patient had mild postoperative seroma which subsided after medical therapy and compression, the second showed wound breakdown due to tumor metastasis and recurrence but did not necessitate implant removal, while the third sequela was a subgaleal hematoma which was aspirated, and the patient healed uneventfully afterward. Esthetic results were highly satisfactory in 75% of the patients (good patient acceptance without touch-ups).ConclusionUltra-high molecular weight polyethylene is in all respects suitable for primary and secondary cranioplasty, combined with computer-aided manufacturing–computer-aided design techniques, excellent esthetic and functional results were achieved. However, proper preoperative planning is important, and we recommend further prospective studies with larger number of patients followed up for longer periods for better assessment.

Artificial intelligence analysis of the sterilization effects on the mechanical properties of human cranial bones

According to the literature, the patient’s own (autologous) bone remains the optimal graft material for cranioplasty. Autografts have an undoubted advantage over competing plastic materials of complete biological compatibility, as well as the absence of interstitial conflict and accessibility. Presently there is still not a single synthetic material that meets all the complex requirements for skull reconstruction in children due to the special complication of accommodating the skull structure that continues to grow. At the same time, the use of autograft is accompanied by the highest percentage of complications in the form of resorption and infection. The purpose of the present study was to evaluate the large volume of measurements (“big data”) obtained after nano-hardness testing of an autograft bone after various preliminary treatments. The latter included the currently optimal method of bone sterilization (boiling peroxide treatment). The measurements performed on different patient allografts were compared and the effects of bone treatment on the mechanical properties were evaluated and compared. Due to the complex hierarchical structural organisation of the bone, the correspondence between the composition, processing, structure, and properties of natural human bone materials were not obvious. Machine Learning, part of the Artificial Intelligence (AI) tool set, was applied to reveal the differences between scull bones of different types, treatment history and patients. It was found that after obtaining the principal mechanical properties of the chosen human skull bone sample it was possible to identify algorithmically the nature of prior bone sterilization and the patient’s sex.

Complications and Failures of Autologous Heterotopic Cranial Bone versus Alloplastic Cranioplasties.

Fresh autologous cranial bone graft has traditionally been regarded as the ideal cranioplasty material; however, long-term comparisons of outcomes with modern alloplastic materials are absent in the literature. The authors evaluated complications and failures among cranioplasties performed with fresh, heterotopic, cranial bone graft versus 3 common alloplastic materials. Random-effects meta-analyses of logit-transformed proportions were performed on studies published between 1971 and 2021 to evaluate complications and failures of cranioplasties performed with fresh, autologous, heterotopic cranial bone; polyetheretherketone (PEEK); polymethylmethacrylate (PMMA); or titanium with a mean follow-up of 12 months or more. Generalized mixed model meta-regressions were performed to account for heterogeneity and to evaluate the contributions of moderators to outcomes variables. A total of 1490 patients (mean age, 33.9 ± 10.8 years) were included. Pooled, all-cause complications were 6.2% for fresh, heterotopic, autologous cranial bone (95% CI, 2.1% to 17.0%; I2 = 55.0; P = 0.02), 18.5% for PEEK (95% CI, 14.0% to 24.0%; I2 = 0.0%; P = 0.58), 26.1% for titanium (95% CI, 18.7% to 35.1%; I2 = 60.6%; P < 0.01), and 28.4% for PMMA (95% CI, 12.9% to 51.5%; I2 = 88.5%; P < 0.01). Pooled all-cause failures were 2.2% for fresh autologous cranial bone (95% CI, 0.4% to 10.6%; I2 = 0.0%; P = 0.45), 6.3% for PEEK (95% CI, 3.2% to 12.3%; I2 = 15.5%; P = 0.31), 11.4% for titanium (95% CI, 6.7% to 18.8%; I2 = 60.8%; P < 0.01), and 12.7% for PMMA (95% CI, 6.9% to 22.0%; I2 = 64.8%; P < 0.01). Meta-regression models indicated that each alloplastic subtype significantly and independently predicted higher complications, whereas titanium and PMMA were significant predictors for all-cause failures compared with autologous bone. All 3 subtypes were predictive of higher cranioplasty failures secondary to infection compared with autologous bone. Cranioplasties performed with fresh, autologous, heterotopic cranial bone grafts resulted in lower complication and failure rates compared with alloplastic materials.

Bipedicled Scalp Flap for Coverage of a Frontal Loss of Substance: About One Case

Introduction: Scalp defects are frequent in the daily practice of plastic surgeons. Their etiologies are multiple; they can be of tumoral origin, infectious, secondary to a burn, post-traumatic… The great vascular richness of the scalp explains the possibility of using local flaps. Clinical Case: This is an 80-year-old patient with ATCD: arterial hypertension under treatment. The onset of symptoms dates back 10 years when the patient was operated on by neurosurgeons for a frontal meningioma for which she underwent excision + cranioplasty. The patient presented after 10 years for cranioplasty rejection with signs of local infection. The decision to remove the prosthetic material and cover the loss of substance was taken. After removal of the cranioplasty material by the team of neurosurgeons, we decided to perform a bi-pedicled scalp flap vascularized by the occipital pedicle and the posterior auricular pedicle, the donor area was grafted. The postoperative course was unremarkable. The result was considered good without complications. Conclusion: The anatomical particularities of the scalp explain all the originality of the reconstructions of this region. In our patient, the advantage of using the bipediculated flap is its extreme reliability, especially when the cranial vault has to be sacrificed.

Establishing proof of concept for sonolucent cranioplasty and point of care ultrasound imaging after posterior fossa decompression for Chiari malformation

BackgroundEvaluation after posterior fossa decompression for Chiari malformation can require repeated imaging, particularly with persistent symptoms. Typically, CT or MRI is used. However, CT carries radiation risk and MRI is costly. Ultrasound is an inexpensive, radiation-free, point-of-care modality that has, thus far, been limited by intact skull and traditional cranioplasty materials. Ultrasound also allows for imaging in different head positions and body postures, which may lend insight into cause for persistent symptoms despite adequate decompression on traditional neutral static CT or MRI. We evaluate safety and feasibility of ultrasound as a post-operative imaging modality in patients reconstructed with sonolucent cranioplasty during posterior fossa decompression for Chiari malformation. MethodsOutcomes were analyzed for 26 consecutive patients treated with a Chiari-specific sonolucent cranioplasty. This included infection, need for revision, CSF leak, and pseudomeningocele. Ultrasound was performed point-of-care in the outpatient clinic by the neurosurgery team to assess feasibility. ResultsIn eight months mean follow up, there were no surgical site infections or revisions with this novel sonolucent cranioplasty. Posterior fossa anatomy was discernable via transcutaneous ultrasound obtained point-of-care in the clinic setting at follow up visits. ConclusionWe demonstrate proof of concept for ultrasound as a post-operative imaging modality after posterior fossa decompression for Chiari malformation. With further investigation, ultrasound may prove to serve as an alternative to CT and MRI in this patient population, or as an adjunct to provide positional and dynamic information. Use of sonolucent cranioplasty is safe. This technique deserves further study.

Cranial meningioma with bone involvement: surgical strategies and clinical considerations

BackgroundIntracranial meningioma with bone involvement and primary intraosseous meningioma is uncommon. There is currently no consensus for optimal management. This study aimed to describe the management strategy and outcomes for a 10-year illustrative cohort, and propose an algorithm to aid clinicians in selecting cranioplasty material in such patients.MethodsA single-centre, retrospective cohort study (January 2010–August 2021). All adult patients requiring cranial reconstruction due to meningioma with bone involvement or primary intraosseous meningioma were included. Baseline patient and meningioma characteristics, surgical strategy, and surgical morbidity were examined. Descriptive statistics were performed using SPSS v24.0. Data visualisation was performed using R v4.1.0.ResultsThirty-three patients were identified (mean age 56 years; SD 15) There were 19 females. Twenty-nine patients had secondary bone involvement (88%). Four had primary intraosseous meningioma (12%). Nineteen had gross total resection (GTR; 58%). Thirty had primary ‘on-table’ cranioplasty (91%). Cranioplasty materials included pre-fabricated polymethyl methacrylate (pPMMA) (n = 12; 36%), titanium mesh (n = 10; 30%), hand-moulded polymethyl methacrylate cement (hPMMA) (n = 4; 12%), pre-fabricated titanium plate (n = 4; 12%), hydroxyapatite (n = 2; 6%), and a single case combining titanium mesh with hPMMA cement (n = 1; 3%). Five patients required reoperation for a postoperative complication (15%).ConclusionMeningioma with bone involvement and primary intraosseous meningioma often requires cranial reconstruction, but this may not be evident prior to surgical resection. Our experience demonstrates that a wide variety of materials have been used successfully, but that pre-fabricated materials may be associated with fewer postoperative complications. Further research within this population is warranted to identify the most appropriate operative strategy.

Considerations for Choice of Cranioplasty Material for Pediatric Patients

Introduction: Optimal material and timing of cranioplasty in the pediatric population continue to be debated. Autologous and alloplastic materials have various indications for use and risk factors for complications. Methods: A single-center retrospective cohort study was undertaken of all pediatric patients who underwent cranioplasty with any material from 1991–2021. Results: 149 cranioplasty implants were included. Younger age (6 years old or under), a diagnosis of craniosynostosis as reason for implant, use of autologous bone, and shorter times to cranioplasty were predictive of need for revision surgery. No factors studied had a statistically significant impact on rate of removal of implant at time of revision surgery. Conclusion: Autologous and alloplastic cranioplasty materials both have good outcomes with low rates of revision surgery in the pediatric population. Alloplastic implants may be considered in the setting of infection as reason for craniectomy given the lower rate of revision surgery and need for removal. Patients with craniosynostosis as reason for cranioplasty have a higher risk of requiring revision or additional surgeries, regardless of implant used.

Cranioplasty in Brain Tumor Surgery: A Single-Center Retrospective Study Investigating Cranioplasty Failure and Tumor Recurrence

Cranioplasty with synthetic implant can be performed to restore function and form of the skull after resection of malignancy infiltrating the bone. The aim of this study was to examine the rate of implant failure and tumor recurrence in patients undergoing nonautologous cranioplasty and tumor resection. In this retrospective single-center study, 48 patients were identified who had undergone cranioplasty with synthetic implants after tumor resection between 2010 and 2020. The medical records were analyzed to investigate patient demographics, surgery data, cranioplasty failure rates, and rate of tumor recurrence. Cranioplasty failed in 8 patients. The median time to implant failure was 220 days with most failures occurring within 1 year (5 of 8). There was no significant difference in rate or time to failure between the different cranioplasty materials (P= 0.39). Low body mass index (P < 0.05), previous craniectomy/cranioplasty (P < 0.05), previous radiation therapy to the brain/skull (P < 0.05), and skin closure with sutures (P < 0.05) were associated with an increased risk of implant failure. Tumors recurred in 15 patients. Cranioplasty surgery with synthetic implants carries a relatively high risk of failure, regardless of type of cranioplasty material used. Skin closure with staples may be beneficial in these patients.

Cranioplasty Using Three-Dimensional-Printed Polycaprolactone Implant and Free Latissimus Dorsi Musculocutaneous Flap in a Patient with Repeated Wound Problem following Titanium Cranioplasty.

Titanium mesh is an alloplastic material widely used for the reconstruction of moderate-to-large skull defects. Repeated wound problems or infection following these reconstructions inevitably lead to the replacement of the cranioplasty material. Among the various alloplastic materials, polycaprolactone implants are usually used for the coverage of small defects such as burr holes. 1 Herein, we present a case of a large cranial defect successfully reconstructed with three-dimensional-printed polycaprolactone implant and a free latissimus dorsi musculocutaneous flap. Until 1-year follow-up, the patient showed a favorable esthetic outcome with no complications or wound relapse.

Cranioplasty for Skull Defects With Polypropylene Abdominal Wall Mesh

Cranioplasty is a well-established common surgery in the practice of neurosurgery and craniofacial surgery. In young patients, complete skull defect closure by bone splitting may be troublesome due to the difficulty to obtain enough bone area. In such cases, sometimes the authors need to use allografts, which may not be widely available in rural practice. In this study, the authors present the series of cranioplasty with polypropylene mesh, which is widely used in abdominal wall closure. Nine patients with depressed compound skull fracture were treated by performing this technique. Selection criteria were: compound depressed skull fractures in which bones were fragmented in a way not able to be reconstructed with and leaving a skull defect, small-sized or relatively medium-sized skull defects, and skull defects not located on the sharp curvatures of the skull which needs firm bended meshes. All patients were male and their ages ranged between 8 months and 36 years.The skull bone defect was reconstructed with polypropylene abdominal wall mesh, which was sutured circumferentially with the galeal tissue. Skull defects were successfully treated in all patients. The follow-up period ranged from 4 to 13 months. One patient with a history of alcoholism and neglectance developed a wound infection after 3 weeks of surgery. This patient was treated successfully with intravenous antibiotics without the need to remove the mesh. There were no complications in the remaining 8 patients. Polypropylene mesh is a cheap and effective material for the reconstruction of small-sized or medium-sized skull defects. It can be a good alternative in rural practice and/or low economic communities, when other cranioplasty materials are not available.

Materials Used in Cranial Reconstruction: A Systematic Review and Meta-Analysis

Cranioplasty is a common neurologic procedure, with complication rates ranging from 20% to 50%. It is hypothesized that the risks of various complications are affected by which material is used for cranioplasty. To evaluate the literature comparing rates of complications after cranioplasty using different materials including autologous bone, hydroxyapatite, methyl methacrylate, demineralized bone matrix, polyetheretherketone, titanium, or composite materials. The PubMed/MEDLINE database was searched for relevant articles published between 2010 and 2020. After screening, 35 articles were included. Outcomes included infection, wound problems, poor cosmesis, overall complications, duration of surgery, and length of stay. For each outcome, a frequentist network meta-analysis was conducted to compare materials used. The risk of infection was 1.62 times higher when methyl methacrylate was used compared with autologous bone (relative risk, 1.62; 95% confidence interval [CI], 1.07-2.45). Length of stay after cranioplasty was on average 3.62 days shorter when titanium was used compared with autologous bone (95% CI, 6.26 to -0.98). The networks constructed for other outcomes showed moderate to substantial between-study heterogeneity, wide CIs, and no significant differences between materials. The quality of existing literature on this topic is relatively poor, almost exclusively comprising single-center retrospective studies. There is not strong enough evidence available to make comprehensive conclusions regarding the risk profiles of various cranioplasty materials across multiple outcomes. Prospective randomized trials are necessary to confirm the significant results found in this analysis and to further elucidate the differential risks of various cranioplasty materials.

Predicting the Impact of Race and Socioeconomic Status on Cranioplasty Materials and Outcomes

Cranioplasty can be performed with either autologous or synthetic materials. No clear consensus has been reached regarding which material is superior and which social factors might influence the choice of treatment modality and the outcomes. We investigated the effects of race and socioeconomic status on the implant choice and outcomes. We conducted a cross-sectional study of adult cranioplasty patients from 2002 to 2017 using the National Inpatient Sample. Autologous implant use, admission costs, length of stay (LOS), and home discharge were analyzed by race, income quartile, and insurance type using multivariable regression models. A total of 105,714 admissions met the inclusion criteria. Most of the patients were women (50.3%) and White (73.7%). Black, other race, and Medicaid patients had greater odds of autologous graft usage, and patients in the 76th-100th income quartile had lower usage. Higher income patients (51th-75th and 76th-100th) had had significantly higher hospitalization costs, amounting to a $1547.2 increase, compared with the bottom quartile. The Medicaid patients had a longer LOS (odds ratio, 1.06; P= 0.008) and decreased rates of home discharge (odds ratio, 0.41; P < 0.001). We found increased autologous cranioplasty usage for non-White and Medicaid patients and increased use of higher cost synthetic implants for high-income patients. Non-White patients and those from higher income quartiles incurred higher admission costs. Medicaid patients had a longer LOS and decreased rates of home discharge.

Cranioplasty with hydroxyapatite or acrylic is associated with a reduced risk of all-cause and infection-associated explantation

Objective Cranioplasty remains an essential procedure following craniectomy but is associated with high morbidity. We investigated factors associated with outcomes following first alloplastic cranioplasty. Methods A single-centre, retrospective cohort study of patients undergoing first alloplastic cranioplasty at a tertiary neuroscience centre (01 March 2010–01 September 2021). Patient demographics and craniectomy/cranioplasty details were extracted. Primary outcome was all-cause explantation. Secondary outcomes were explantation secondary to infection, surgical morbidity and mortality. Multivariable analysis was performed using Cox proportional hazards regression or binary logistic regression. Results Included were 287 patients with a mean age of 42.9 years [SD = 15.4] at time of cranioplasty. The most common indication for craniectomy was traumatic brain injury (32.1%, n = 92). Cranioplasty materials included titanium plate (23.3%, n = 67), hydroxyapatite (22.3%, n = 64), acrylic (20.6%, n = 59), titanium mesh (19.2%, n = 55), hand-moulded PMMA cement (9.1%, n = 26) and PEEK (5.6%, n = 16). Median follow-up time after cranioplasty was 86.5 months (IQR 44.6–111.3). All-cause explantation was 12.2% (n = 35). Eighty-three patients (28.9%) had surgical morbidity. In multivariable analysis, the risk of all-cause explantation and explantation due to infection was reduced with the use of both hydroxyapatite (HR 0.22 [95% CI 0.07–0.71], p = .011, HR 0.22 [95% CI 0.05–0.93], p = .040) and acrylic (HR 0.20 [95% CI 0.06–0.73], p = .015, HR 0.24 [95% CI 0.06–0.97], p = .045), respectively. In addition, risk of explantation due to infection was increased when time to cranioplasty was between three and six months (HR 6.38 [95% CI 1.35–30.19], p = .020). Mean age at cranioplasty (HR 1.47 [95% CI 1.03–2.11], p = .034), titanium mesh (HR 5.36 [95% CI 1.88–15.24], p = .002), and use of a drain (HR 3.37 [95% CI 1.51–7.51], p = .003) increased risk of mortality. Conclusions Morbidity is high following cranioplasty, with over a tenth requiring explantation. Hydroxyapatite and acrylic were associated with reduced risk of all-cause explantation and explantation due to infection. Cranioplasty insertion at three to six months was associated with increased risk of explantation due to infection.

A fully ingrowing implant for cranial reconstruction: Results in critical size defects in sheep using 3D-printed titanium scaffold.

Current alloplastic materials such as PMMA, titanium or PEEK don't show relevant bone ingrowth into the implant when used for cranioplasty, ceramic implants have the drawback being brittle. New materials and implant designs are urgently needed being biocompatible, stable enough for cranioplasty and stimulating bone formation. In an in vivo critical size sheep model circular cranial defects (>2.4cm) were covered with three different types of a 3D-printed porous titanium scaffolds with multidirectional, stochastically distributed architecture (uncoated scaffold, hydroxyapatite-coated scaffold, uncoated scaffold filled with a calcium phosphate bone cement paste containing β-TCP granules). An empty titanium mesh served as control. Among the different investigated setups the hydroxyapatite-coated scaffolds showed a surprisingly favourable performance. Push-out tests revealed a 2.9 fold higher force needed in the hydroxyapatite-coated scaffolds compared to the mesh group. Mean CT density at five different points inside the scaffold was 2385HU in the hydroxyapatite-coated group compared to 1978HU in the uncoated scaffold at nine months. Average lateral bone ingrowth after four months in the hydroxyapatite-coated scaffold group was up to the implant center, 12.1mm on average, compared to 2.8mm in the control group covered with mesh only. These properties make the investigated scaffold with multidirectional, stochastically distributed structure superior to all products currently on the market. The study gives a good idea of what future materials for cranioplasty might look like.

Clinical Application of Three-Dimensional Printing of Polycaprolactone/Beta-Tricalcium Phosphate Implants for Cranial Reconstruction

:Polycaprolactone (PCL) implants are a biodegradable polymeric material with appropriate mechanical strength and durability for use in cranioplasty. They can be manufactured as patient- customized implants using a three-dimensional (3D) printer. Herein, the authors aimed to share our experience in cranioplasty of patients with deformed and asymmetric skulls using PCL/beta- tricalcium phosphate (ß-TCP) implants.Seven patients underwent cranioplasty using patient-specific PCL/ß-TCP implants. Cranial computed tomography images were converted to a 3D model and mirrored to design a patient-specific implant. Based on the 3D simulation, an implant was 3D printed using PCL/ß-TCP. A 6-month follow-up was conducted with periodic visits and computed tomography scans. Symmetry after surgery and complications were evaluated.Postoperatively, the soft tissue volumes increased to 15.8 ± 17.2 cm3 and 14.9 ± 15.7 cm3 at 2 weeks and 6 months of follow-up, respectively. The volume change from 2 weeks to 6 months was —4.4 ± 2.5%. Six patients achieved complete symmetry after cranioplasty, whereas 1 patient noticed partial symmetry. The symmetry remained unchanged at 6 months of follow-up. Upon palpation to assess smoothness, 6 patients exhibited a smooth edge interface, whereas 1 patient had a slightly irregular edge.Based on these findings, 3D-printed PCL/ß-TCP implants are an excellent material for cranioplasty, and a favorable cosmetic outcome can be achieved. Specifically, these novel PCL/ß-TCP implants have good biocompatibility and mechanical strength without any postoperative foreign body reaction.

The Antibiotic Immersion of Custom-Made Porous Hydroxyapatite Cranioplasty: A Multicentric Cohort Study.

Cranioplasty is a common neurosurgical procedure performed to reconstruct cranial defects. The most common cranioplasty materials used today can be divided into 2 types: autologous bone and bone substitutes, such as polyetheretherketone, titanium mesh, poly-methyl methacrylate, and Hydroxyapatite (HA). Infection represents one of the most feared complications, ranging from 2.3% to 20%. Early implant infections occur within 30 days from the operation and are mostly due to pathogens from the skin and the paranasal cavity. The authors aim to demonstrate the efficacy of our preoperative antibiotic immersion protocol of custom-made HA prosthesis, to prevent early implant infections. The authors compare this population to cranioplasties without preoperative antibiotic elution and those with anonstandardized antibiotic elution. The authors retrospectively analyzed data from patients referred to 6 different hospitals in northern Italy, in the period 2000 to 2020. Inclusion criteria were patients requiring reconstruction of thecal bone with HA prosthesis after post-traumatic decompressive surgery; age more than 18 years; detailed patient history and clinical data; and follow-up of minimum 6 months. A total of 77 cranioplasties were included in the study, along with 120 retrospective cases in comparison. Infections occurred in 2.6% of cranioplasties with antibiotic immersion compared to 7.8% of cranioplasties without. Even if nonsignificant, these results support our hypothesis that pretreatment of HA implants with antibiotic appears to prevent cranioplasty infections and could be a viable option to improve cranioplasty outcomes in the future.

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.