Comparison of Complications Following Cranioplasty Using a Sterilized Autologous Bone Flap or Polymethyl Methacrylate

A Smile Reimagined: Gummy Smile Resolution with Cutting Edge Method Using Chu's Gauge and Polymethylmethacrylate (PMMA) Bone Cement

Excessive gingival display (EGD) is one of the most common aesthetic concerns, and its correction often presents a challenge to periodontists. It has a multifactorial etiology, and this article describes a case involving hypermobile upper lip (HUL), altered passive eruption (APE), and vertical maxillary excess (VME). Upon investigation, a positive collum angle and marked subnasal skeletal depression were observed. In this context, it is noted that during a spontaneous smile, the upper lip retracts and gets lodged in this depression. The rehabilitation plan includes included aesthetic crown lengthening via gingivectomy using Chu's proportional gauge for altered passive eruption and filling the subnasal depression by PMMA (polymethylmethacrylate) bone cement. The entire treatment plan was digitalised using cutting edge methods such as computed tomography (CT), cone beam computed tomography (CBCT), and 3D printers for virtual planning of the defect's position, size, and shape. No postoperative complications were reported. After six months, the patient exhibited a harmonious smile with reduced exposed gingiva.

Patient Satisfaction and Radiologic Assessability After Treatment of Complex Skull Defects With a Custom-Made Cranioplasty From a Thin Titanium Sheet

OBJECTIVE

The cosmetically good coverage of skull defects is a challenge in neurosurgical clinics. In addition, the skull treated with implants and the underlying structures must remain radiologically assessable. In this examination, the postoperative courses of patients after implantation of CranioTop is described. Digital x-ray, computed tomography, and magnetic resonance images after implantation of CranioTop were evaluated with regard to their assessability.

MATERIALS AND METHODS

Between 2018 and 2020, 23 titanium cranioplasties (CranioTop) were implanted to 21 patients. The intraoperative handling, the accuracy of fit, the healing process, the cosmetic result and the physical condition of the patients were examined. In addition, digital x-rays, magnetic resonance imaging, and computed tomography scans of the cranium supplied with CranioTop were examined.

RESULTS

The evaluation showed good to very good results regarding patients' satisfaction. There were no severe complications; thirteen patients found the cosmetic result very good; 8 patients assessed the cosmetic result as good. Because of the low thickness and density of the CranioTop plastic there was only low formation of radial stripe artifacts (streaking) and susceptibility artifacts. The assessment of digital x-ray, computed tomography, and magnetic resonance imaging images is possible after implantation of CranioTop.

CONCLUSION

The patients treated with CranioTop showed a high level of satisfaction with regard to the cosmetic result and their physical condition. Furthermore, the cranium supplied with CranioTop remains well assessable in radiologic imaging with only slight limitations in magnetic resonance imaging.

Meta-Analysis and Meta-Regression of Complications and Failures of Autologous Heterotopic Cranial Bone versus Alloplastic Cranioplasties

BACKGROUND

Fresh autologous cranial bone graft has been traditionally regarded as the ideal cranioplasty material, however long-term comparisons of outcomes with modern alloplastic materials are absent in the literature. In this work, we evaluated complications and failures among cranioplasties performed with fresh, heterotopic, cranial bone graft versus three common alloplastic materials.

METHODS

Random-effects meta-analyses of logit-transformed proportions were performed on studies published between 1971-2021 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 ≥12 months. Generalized mixed model meta-regressions were performed to account for heterogeneity and to evaluate the contributions of moderators to outcomes variables.

RESULTS

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% confidence interval [CI]:2.1-17.0%; I2=55.0%, p=0.02), 18.5% for PEEK (95%CI:14.0-24.0%; I2=0.0%, p=0.58), 26.1% for titanium (95%CI:18.7-35.1%; I2=60.6%, p<0.01), and 28.4% for PMMA (95%CI:12.9-51.5%; I2=88.5%, p<0.01). Pooled all-cause failures were 2.2% for fresh, autologous cranial bone (95%CI:0.4-10.6%; I2=0.0%, p=0.45), 6.3% for PEEK (95%CI:3.2-12.3%; I2=15.5%, p=0.31), 11.4% for titanium (95%CI:6.7-18.8%; I2=60.8%, p<0.01), and 12.7% for PMMA (95%CI:6.9-22.0%; I2=64.8%, p<0.01). Meta-regression models indicated that each alloplastic subtype significantly and independently predicted higher complications, while titanium and PMMA were significant predictors for all-cause failures compared to autologous bone. All three subtypes were predictive of higher cranioplasty failures secondary to infection compared to autologous bone.

CONCLUSIONS

Cranioplasties performed with fresh, autologous heterotopic cranial bone grafts resulted in lower complications and failures compared to alloplastic materials.

3D-printed PMMA implant for gingival smile treatment through the VISTA technique: A report of a new approach

BACKGROUND

A gingival display higher than 3 mm is considered a characteristic of a gingival smile (GS). Several etiological factors have been associated to GS and for this reason various treatments have been proposed according to its etiology. The aim of this study is to present a case with an alternative technique to treat GS with minimally invasive vestibular incision subperiosteal tunnel access (VISTA) and polymethyl methacrylate (PMMA) implants for lip repositioning.

METHODS AND RESULTS

The patient, a 25-year-old woman diagnosed with excessive gingival exposure, had previously done botulinum toxin (BoNT) injections and did not like the result. She had a major subnasal depression and the upper lip would lodge in there during spontaneous smile. She was informed about all options of treatment and agreed to a lip repositioning installing a customized PMMA implant.

CONCLUSION

This is the first study to our knowledge to present a case with use of a PMMA implant associated with the VISTA approach for lip repositioning and gingival smile correction. The results are encouraging, and the patient was satisfied with results accomplished by this technique.

KEY POINTS

Why is this case new information? This is a new and innovative surgical approach for gingival smile with PMMA implants through a minimally invasive technique (VISTA). What are the keys to successful management of this case? Well-defined presurgical planning and the presence of the upper lip lodging in the subnasal depression during spontaneous smile. What are the primary limitations to success in this case? Cases with vertical maxillary excess and those in which osteotomy/osteoplasty is indicated. It is a technique-sensitive treatment dependent on the clinician's experience.

Decompressive Craniectomy in Severe Traumatic Brain Injury: The Intensivist's Point of View

INTRODUCTION

Traumatic brain injury (TBI) represents a severe pathology with important social and economic concerns, decompressive craniectomy (DC) represents a life-saving surgical option to treat elevated intracranial hypertension (ICP). The rationale underlying DC is to remove part of the cranial bones and open the dura mater to create space, avoiding secondary parenchymal damage and brain herniations. The scope of this narrative review is to summarize the most relevant literature and to discuss main issues about indication, timing, surgical procedure, outcome, and complications in adult patients involved in severe traumatic brain injury, underwent to the DC. The literature research is made with Medical Subject Headings (MeSH) terms on PubMed/MEDLINE from 2003 to 2022 and we reviewed the most recent and relevant articles using the following keywords alone or matched with each other: decompressive craniectomy; traumatic brain injury; intracranial hypertension; acute subdural hematoma; cranioplasty; cerebral herniation, neuro-critical care, neuro-anesthesiology. The pathogenesis of TBI involves both primary injuries that correlate directly to the external impact of the brain and skull, and secondary injuries due to molecular, chemical, and inflammatory cascade inducing further cerebral damage. The DC can be classified into primary, defined as bone flap removing without its replacement for the treatment of intracerebral mass, and secondary, which indicates for the treatment of elevated intracranial pressure (ICP), refractory to intensive medical management. Briefly, the increased brain compliance following bone removal reflects on CBF and autoregulation inducing an alteration in CSF dynamics and so, eventual complications. The risk of complications is estimated around 40%. The main cause of mortality in DC patients is due to brain swelling. In traumatic brain injury, primary or secondary decompressive craniectomy is a life-saving surgery, and the right indication should be mandatory in multidisciplinary medical-surgical consultation.

Outcomes and Associated Complications of Cranioplasty following Craniectomy in Brunei Darussalam

Objective Cranioplasty, commonly performed after decompressive craniectomy, is associated with significant complications. We aim to characterize the outcomes and complications post cranioplasty performed in Brunei Darussalam.

Methods and Materials We conducted a nationwide retrospective study of the patients who underwent cranioplasty. Patients who underwent cranioplasty by the Neurosurgical Department from January 2014 to June 2019 were included. Patients were excluded if they did not have a minimum of 30-days follow-up or the initial cranioplasty was performed elsewhere. Outcomes including complications post cranioplasty and 30-day and 1-year failure rates were assessed. All statistical analyses were performed with SPSS version 20 (IBM Corporation, Armonk, New York, USA). The χ2 test, Student's t-test, and the Mann–Whitney U test were performed for nominal, normally, and non-normally distributed variables, respectively. Multivariate logistic regression was used to assess predictors for complications and cranioplasty failure.

Results Seventy-seven patients with a median age of 48 (interquartile range, 37–61) years were included. Most cranioplasties used autologous bone (70/77, 90.9%). Infection and overall complication rates were 3.9% and 15.6%, respectively. Cranioplasty failure (defined as removal or revision of cranioplasty) rate was 9.1%. Previous cranial site infection post craniectomy was associated with cranioplasty failure (odds ratio: 12.2, 95% confidence interval [1.3, 114.0], p=0.028).

Conclusions Cranioplasty is generally associated with significant complications, including reoperation for implant failure. We highlighted that autologous bone cranioplasties can be performed with an acceptable low rate of infection, making it a viable first option for implant material.

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.

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

BACKGROUND

Cranioplasty is a common neurological procedure with complication rates ranging from 20% to 50%. It is hypothesized that the risks of various complications are impacted by which material is used for cranioplasty.

OBJECTIVE

To evaluate existing literature comparing rates of complications following cranioplasty using different materials including autologous bone, hydroxyapatite, methyl methacrylate (MMA), demineralized bone matrix, polyetheretherketone, titanium, or composite materials.

METHODS

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.

RESULTS

The risk of infection was 1.62 times higher when MMA was used compared to autologous bone (RR 1.62, 95% CI 1.07 to 2.45). Length of stay following cranioplasty was on average 3.62 days shorter when titanium was used compared autologous bone (95% CI -6.26 to -0.98). The networks constructed for other outcomes demonstrated moderate to substantial between-study heterogeneity, wide confidence intervals, and no significant differences between materials.

CONCLUSIONS

The quality of existing literature on this topic is relatively poor, almost exclusively comprised of single-center retrospective studies. There is currently 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.

Characterisation of Selected Materials in Medical Applications

Tissue engineering is an interdisciplinary field of science that has developed very intensively in recent years. The first part of this review describes materials with medical and dental applications from the following groups: metals, polymers, ceramics, and composites. Both positive and negative sides of their application are presented from the point of view of medical application and mechanical properties. A variety of techniques for the manufacture of biomedical components are presented in this review. The main focus of this work is on additive manufacturing and 3D printing, as these modern techniques have been evaluated to be the best methods for the manufacture of medical and dental devices. The second part presents devices for skull bone reconstruction. The materials from which they are made and the possibilities offered by 3D printing in this field are also described. The last part concerns dental transitional implants (scaffolds) for guided bone regeneration, focusing on polylactide–hydroxyapatite nanocomposite due to its unique properties. This section summarises the current knowledge of scaffolds, focusing on the material, mechanical and biological requirements, the effects of these devices on the human body, and their great potential for applications.

Labial Repositioning Using Print Manufactured Polymethylmethacrylate- (PMMA-) Based Cement for Gummy Smile

Treating patients with excessive gingival display (EGD) to provide them with a pleasant smile is a challenge to periodontists. A gummy smile can be due to excessive vertical bone growth, dentoalveolar extrusion, short upper lip, upper lip hyperactivity, or altered passive eruption (APE). In addition, many patients have a lack of lip support due to marked depression of the anterior process of the maxilla. In these cases, lip repositioning using polymethylmethacrylate (PMMA) cement could be performed. This article describes a case of EGD with subnasal depression. In the clinical examination, the presence of a marked subnasal depression was found, in which the upper lip lodged during a spontaneous smile. In addition to this, gingival exposure extending from the maxillary molar on one side of the mouth to the one on the opposite side was also found during the spontaneous smile. Therefore, the periodontal surgical intervention proposed consisted of performing a procedure to fill the subnasal depression with PMMA cement. This article describes a digital approach to plan the use of PMMA cement in lip repositioning in a patient with gummy smile and subnasal depression. The patient reported no postoperative complications. Six months after the surgery, the patient revealed a more harmonious smile than before, with reduction in the gingival exposure and new adequate support for and repositioning of the upper lip.

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.

Cranioplasty Following Severe Traumatic Brain Injury: Role in Neurorecovery

PURPOSE OF REVIEW

Decompressive craniectomy (DC) is a life-saving procedure performed in refractory intracranial pressure increase and mass lesion due to severe traumatic brain injury (TBI). Cranioplasty primarily intends to maintain cerebral protection and reconstruct aesthetic appearance. Also, cranioplasty can enable neurological rehabilitation and potentially augment neurological recovery. This article reviews recent studies on the effect of cranioplasty on neurological recovery in severe TBI.

RECENT FINDINGS

Recent findings suggested that cranioplasty has the potential to enhance neurological recovery after severe TBI. Cranioplasty may alleviate cognitive and functional deficits by reinstating the regular cerebrospinal fluid dynamics and improving brain perfusion. Analyses on the effects of cranioplasty timing on neurological recovery likely favor early cranioplasty. Also, materials used during cranioplasty, autologous and exogenous, were suggested to have similar effects in recovery. Although neurological therapy of TBI patients is still a serious challenge, recent findings represent the possible enhancing effect of cranioplasty on neurological recovery.

Complications of Cranioplasty in Relation to Material: Systematic Review, Network Meta-Analysis and Meta-Regression

BACKGROUND

Cranioplasty is a ubiquitous neurosurgical procedure consisting of reconstruction of a pre-existing calvarial defect. Many materials are available, including polymethylmethacrylate in hand-moulded (hPMMA) and prefabricated (pPMMA) form, hydroxyapatite (HA), polyetheretherketone (PEEK) and titanium (Ti).

OBJECTIVE

To perform a network meta-analysis (NMA) to assess the relationship between materials and complications of cranioplasty.

METHODS

PubMed/MEDLINE, Google Scholar, EMBASE, Scopus, and The Cochrane Library were searched from January 1, 1990 to February 14, 2021. Studies detailing rates of any of infections, implant exposure, or revision surgery were included. A frequentist NMA was performed for each complication. Risk ratios (RRs) with 95% CIs were calculated for each material pair.

RESULTS

A total of 3620 abstracts were screened and 31 full papers were included. Surgical revision was reported in 18 studies and occurred in 316/2032 cases (14%; 95% CI 11-17). PEEK had the lowest risk of re-operation with a rate of 8/157 (5%; 95% CI 0-11) in 5 studies, superior to autografts (RR 0.20; 95% CI 0.07-0.57), hPMMA (RR 0.20; 95% CI 0.07-0.60), Ti (RR 0.39; 95% CI 0.17-0.92), and pPMMA (RR 0.14; 95% CI 0.04-0.51). Revision rate was 131/684 (19%; 95% CI 13-25; 10 studies) in autografts, 61/317 (18%; 95%CI 9-28; 7 studies) in hPMMA, 84/599 (13%; 95% CI 7-19; 11 studies) in Ti, 7/59 (9%; 95% CI 1-23; 3 studies) in pPMMA, and 25/216 (12%; 95% CI 4-24; 4 studies) in HA. Infection occurred in 463/4667 (8%; 95% CI 6-11) and implant exposure in 120/1651 (6%; 95% CI 4-9).

CONCLUSION

PEEK appears to have the lowest risk of cranioplasty revision, but further research is required to determine the optimal material.

Load-Bearing Capacity and Design Advantages of a Custom-Made, Thin Pure-Titanium Cranioplasty (CranioTop)

BACKGROUND

Adequate and stable coverage of cranial contour and continuity defects of any origin is a common challenge in neurosurgical clinics. This study presents the results of investigations concerning the mechanical load-bearing capacity and design advantages of custom-made implants made from a thin, pure-titanium sheet (CranioTop) (CLinstruments, Attendorn, Germany) for covering complex cranial defects.

METHODS

In 9 test series, the stability of three differently shaped and sized thin titanium sheet implants was tested using vertical, uniaxial compression with 3 different compression stamps, to investigate the behaviour of these implants in relation to punctiform as well as planar forces.

RESULTS

All 9 model implants showed elastic behavior in the synchronously recorded force/displacement diagrams at an impression of up to 2 mm. The forces at 2 mm deformation were between 170.1 and 702.7 Newton.

CONCLUSION

Cranioplasty using CranioTop is a stable procedure for covering skull defects, even those of large dimensions. An added advantage is the significant reduction in effort required to prepare the area of the bone margins compared to other current techniques of cranioplasty.

Consensus statement from the international consensus meeting on post-traumatic cranioplasty

Background

Due to the lack of high-quality evidence which has hindered the development of evidence-based guidelines, there is a need to provide general guidance on cranioplasty (CP) following traumatic brain injury (TBI), as well as identify areas of ongoing uncertainty via a consensus-based approach.

Methods

The international consensus meeting on post-traumatic CP was held during the International Conference on Recent Advances in Neurotraumatology (ICRAN), in Naples, Italy, in June 2018. This meeting was endorsed by the Neurotrauma Committee of the World Federation of Neurosurgical Societies (WFNS), the NIHR Global Health Research Group on Neurotrauma, and several other neurotrauma organizations. Discussions and voting were organized around 5 pre-specified themes: (1) indications and technique, (2) materials, (3) timing, (4) hydrocephalus, and (5) paediatric CP.

Results

The participants discussed published evidence on each topic and proposed consensus statements, which were subject to ratification using anonymous real-time voting. Statements required an agreement threshold of more than 70% for inclusion in the final recommendations.

Conclusions

This document is the first set of practical consensus-based clinical recommendations on post-traumatic CP, focusing on timing, materials, complications, and surgical procedures. Future research directions are also presented.

The storage of skull bone flaps for autologous cranioplasty: literature review

The use of autologous bone flap for cranioplasty after decompressive craniectomy is a widely used strategy that allows alleviating health expenses. When the patient has recovered from the primary insult, the cranioplasty restores protection and cosmesis, recovering fluid dynamics and improving neurological status. During this time, the bone flap must be stored, but there is a lack of standardization of tissue banking practices for this aim. In this work, we have reviewed the literature on tissue processing and storage practices. Most of the published articles are focused from a strictly clinical and surgical point of view, paying less attention to issues related to tissue manipulation. When bone resorption is avoided and the risk of infection is controlled, the autograft represents the most efficient choice, with the lowest risk of complication. Otherwise, depending on the degree of involvement, the patient may have to undergo new surgery, assuming further risks and higher healthcare costs. Therefore, tissue banks must implement protocols to provide products with the highest possible clinical effectiveness, without compromising safety. With a centralised management of tissue banking practices there may be a more uniform approach, thus facilitating the standardization of procedures and guidelines.

Cranial bone flap resorption-pathological features and their implications for clinical treatment

Cranioplasty following decompressive craniectomy (DC) has a primary complication when using the autologous bone: aseptic bone resorption (ABR). So far, risk factors such as age, number of fragments, and hydrocephalus have been identified but a thorough understanding of the underlying pathophysiology is still missing. The aim of this osteopathological investigation was to gain a better understanding of the underlying processes. Clinical data of patients who underwent surgical revision due to ABR was collected. Demographics, the time interval between craniectomy and cranioplasty, and endocrine serum parameters affecting bone metabolism were collected. Removed specimens underwent qualitative and quantitative histological examination. Two grafts without ABR were examined as controls. Compared to the controls, the typical layering of the cortical and cancellous bone was largely eliminated in the grafts. Histological investigations revealed the coexistence of osteolytic and osteoblastic activity within the necrosis. Bone appositions were distributed over the entire graft area. Remaining marrow spaces were predominantly fibrotic or necrotic. In areas with marrow cavity fibrosis, hardly any new bone tissue was found in the adjacent bone, while there were increased signs of osteoclastic resorption. Insufficient reintegration of the flap may be due to residual fatty bone marrow contained in the bone flap which seems to act as a barrier for osteogenesis. This may obstruct the reorganization of the bone structure, inducing aseptic bone necrosis. Following a path already taken in orthopedic surgery, thorough lavage of the implant to remove the bone marrow may be a possibility, but will need further investigation.

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

BACKGROUND

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.

METHODS

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 (494 patients). The endpoints were the incidence of adverse events and of related implant removal.

RESULTS

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 onsite 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%).

CONCLUSIONS

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 complicantions 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.

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.

A retrospective descriptive study of cranioplasty failure rates and contributing factors in novel 3D printed calcium phosphate implants compared to traditional materials

BACKGROUND

Failure rates with cranioplasty procedures have driven efforts to improve graft material and reduce reoperation. One promising allograft source is a 3D-printed titanium mesh with calcium phosphate filler. This study evaluated failure rates and pertinent characteristics of these novel 3D-grafts compared to traditional materials.

METHODS

Sixty patients were retrospectively identified who underwent a cranioplasty between January 2015-December 2017. Specific data points related to graft failure were collected for all surgical admissions, from the primary injury to their most recent. These included, but were not limited to, initial physical exam findings, vitals, comorbid conditions, surgery length, estimated blood loss, incision type, and need for revision. Failure rates of 3D-printed allografts were compared to traditional grafts.

RESULTS

A total of 60 subjects were identified who underwent 71 unique cranioplasty procedures (3D = 13, Synthetic = 12, Autologous = 46). There were 14 total failures, demonstrating a 19.7% overall failure rate. Specifically, 15.4% (n = 2) of 3D, 19.6% (n = 9) of autologous, and 25.0% (n = 3) of synthetic grafts required revision. Patients receiving 3D-grafts had the shortest overall mean surgery times (200.8 ± 54.3 min) and lowest infection rates (7.7%) compared to autologous (210.5 ± 47.9 min | 25.0%) and synthetic models (217.6 ± 77.3 min | 8.7%), though significance was unable to be determined. Tobacco use and trap-door incisions were associated with increased failure rates relative to straight or curved incisions in autologous grafts. Cranioplasties performed less than 3 months after craniectomy appeared to fail more often than those performed at least three months after craniectomy, for the synthetic group.

CONCLUSION

We concluded that 3D-printed cranioplasty grafts may lead to lower failure rates and shorter surgery times compared to traditional cranioplasty materials in our limited population. 3D-implants hold promise for cranial reconstruction after TBI.

Cranioplasty: A Comprehensive Review of the History, Materials, Surgical Aspects, and Complications

Cranioplasty is a common neurosurgical procedure performed to reconstruct cranial defects. The materials used to replace bone defects have evolved throughout history. Cranioplasty materials can be broadly divided into biological and synthetic materials. Biological materials can be further subdivided into autologous grafts, allografts, and xenografts. Allografts (bony materials and cartilage from cadavers) and xenografts (bony materials from animals) are out of favor for use in cranioplasty because of their high rates of infection, resorption, and rejection. In autologous cranioplasty, either the cranial bone itself or bones from other parts of the body of the patient are used. Synthetic bone grafts have reduced the operation time and led to better cosmetic results because of the advancement of computer-based customization and three-dimensional printing. Aluminum was the first synthetic bone graft material used, but it was found to irritate neural tissue, induce seizures, and dissolve over time. Acrylic, in the form of methyl methacrylate, is the most widely used material in cranioplasty. Hydroxyapatite is a natural component of bone and is believed to enhance bone repair, resulting in decreased tissue reactions and promoting good osteointegration. Polyetheretherketones are light and nonconductive and do not interfere with imaging modalities. The complication rates of cranioplasty are high, and surgical site infection is the most common complication. The effect of cranioplasty timing on cognitive function remains debatable. However, the timing of cranioplasty is independent of neurologic outcomes. In this article, the history, materials, complications, and evolution of current practices used in cranioplasty are comprehensively reviewed.

An altered posterior question-mark incision is associated with a reduced infection rate of cranioplasty after decompressive hemicraniectomy

OBJECTIVE

Performing a cranioplasty (CP) after decompressive craniotomy is a straightforward neurosurgical procedure, but it remains associated with a high complication rate. Surgical site infection (SSI), aseptic bone resorption (aBR), and need for a secondary CP are the most common complications. This observational study aimed to identify modifiable risk factors to prevent CP failure.

METHODS

A retrospective analysis was performed of all patients who underwent CP following decompressive hemicraniectomy (DHC) between 2010 and 2018 at a single institution. Predictors of SSI, aBR, and need for allograft CP were evaluated in a univariate analysis and multivariate logistic regression model.

RESULTS

One hundred eighty-six patients treated with CP after DHC were included. The diagnoses leading to a DHC were as follows: stroke (83 patients, 44.6%), traumatic brain injury (55 patients, 29.6%), subarachnoid hemorrhage (33 patients, 17.7%), and intracerebral hemorrhage (15 patients, 8.1%). Post-CP SSI occurred in 25 patients (13.4%), whereas aBR occurred in 32 cases (17.2%). An altered posterior question-mark incision, ending behind the ear, was associated with a significantly lower infection rate and CP failure, compared to the classic question-mark incision (6.3% vs 18.4%; p = 0.021). The only significant predictor of aBR was patient age, in which those developing resorption were on average 16 years younger than those without aBR (p < 0.001).

CONCLUSIONS

The primary goal of this retrospective cohort analysis was to identify adjustable risk factors to prevent post-CP complications. In this analysis, a posterior question-mark incision proved beneficial regarding infection and CP failure. The authors believe that these findings are caused by the better vascularized skin flap due to preservation of the superficial temporal artery and partial preservation of the occipital artery. In this trial, the posterior question-mark incision was identified as an easily and costless adaptable technique to reduce CP failure rates.

Cranioplasty Following Decompressive Craniectomy

Cranioplasty (CP) after decompressive craniectomy (DC) for trauma is a neurosurgical procedure that aims to restore esthesis, improve cerebrospinal fluid (CSF) dynamics, and provide cerebral protection. In turn, this can facilitate neurological rehabilitation and potentially enhance neurological recovery. However, CP can be associated with significant morbidity. Multiple aspects of CP must be considered to optimize its outcomes. Those aspects range from the intricacies of the surgical dissection/reconstruction during the procedure of CP, the types of materials used for the reconstruction, as well as the timing of the CP in relation to the DC. This article is a narrative mini-review that discusses the current evidence base and suggests that no consensus has been reached about several issues, such as an agreement on the best material for use in CP, the appropriate timing of CP after DC, and the optimal management of hydrocephalus in patients who need cranial reconstruction. Moreover, the protocol-driven standards of care for traumatic brain injury (TBI) patients in high-resource settings are virtually out of reach for low-income countries, including those pertaining to CP. Thus, there is a need to design appropriate prospective studies to provide context-specific solid recommendations regarding this topic.

Polymethylmethacrylate patient-matched implants (PMMA-PMI) for complex and revision cranioplasty: analysis of long-term complication rates and patient outcomes

Objective: Cranioplasty (CP) is associated with high complication rates and patient-matched implants (PMI) are frequently used for CP. However, only limited data are available regarding complication rates of PMI-based CP after complex or failed primary CP. Here we report our experience with the use of polymethylmethacrylate (PMMA) PMI for this purpose.Method: We analyzed all patients with complex or failed primary CP and subsequent implantation of PMMA-PMI between 2010 and 2015 at our institution.Results: A total of 67 patients (29 females, 38 males) with a mean age of 43 years (range: 13-74 years) were included in the study. Primary PMI-CP was performed in 18 patients with destructive or osteolytic bone tumors. Secondary PMI-CP was performed in 49 patients. Complications occurred in 14 patients with an overall complication rate of 21.7% during a mean follow-up of 39.7 ± 23.4 month. Approximately two-thirds of the patients reported a good quality of life after the initial event and subsequent CP. The majority of patients (>90%) was satisfied with the cosmetic result.Conclusion: Surgical CP with PMMA-PMI appears to be a suitable method for patients with failed or complex CP. Complication rates are comparable to those reported for primary CP.

Early autologous cranioplasty: complications and identification of risk factors using virtual reality visualisation technique

Background: Cranioplasty (CP) of autologous bone flap after decompressive craniectomy (DC) is known to be associated with a high complication rate, particularly bone flap resorption (BFR). In a retrospective study, we used a novel virtual reality (VR) visualisation technique to identify and evaluate risk factors associated with CP.Method: Twenty-five patients underwent early autologous CP. All complications were recorded. Cranial computed tomography scans were visualised via the VR software to access the fitting accuracy of the bone flap (bone flap size, gap width at trepanation cutting edge, extent of osteoclastic extension).Results: An overall complication rate of 44% was seen, and BFR was the most common (36%). Only 'osteoclastic extension of trepanation' (p = .04) was a significant risk factor for BFR. The factors 'indication for DC' (p = .09) and 'size of bone flap' (p = .09) had a tendency towards influencing the rate of BFR, while 'age' (p = .68), 'time interval between DC and CP' (p = 1.00), and 'gap width' (p = .50) were not considered to influence the BFR rate.Conclusions: DC and subsequent CP is a complication-prone procedure. Therefore, it is relevant to identify and quantify probable risk factors for the most common complications, such as BFR. Here, we found that the extent of osteoclastic extension may impair the patient's healing process. Our investigation was made considerably easier by using the novel VR visualisation technique, which allows parallax free measurements of distances in 3D space.

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.

Labial repositioning using polymethylmethracylate (PMMA)-based cement for esthetic smile rehabilitation-A case report

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PMMA-based bone cement proved effective in esthetic smile rehabilitation.

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The technique is operator-sensitive.

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The thickness of the PMMA implant is also paramount.

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PMMA is non-toxic, biocompatible with human tissues.

Introduction

One of the most common esthetic complaints among dental patients is a gingival smile, which may be of multifactorial etiology, e.g. gingival hyperplasia, skeletal deformities featuring overgrowth of the anterior maxilla, altered passive eruption, maxillary alveolar tooth extrusion, fine lip and hypermobility of lip elevator muscles, which must be diagnosed prior to treatment so that the appropriate management approach can be selected. Maxillary overgrowth may give rise to subnasal skeletal depression where the upper lip retracts to during smiling, causing gingival exposure. The objective of this case report was to describe a lip repositioning technique using polymethylmethacrylate (PMMA)-based bone cement for esthetic smile rehabilitation.

Case report

A 23-year-old female attended the Esthetic Dentistry Clinic of our institute, reporting dissatisfaction with her smile, due to the size of her teeth and the amount of gingiva exposed when smiling. A rehabilitation planning was designed, which was performed with periodontal surgical intervention to fill the subnasal depression with PMMA-based bone cement. After crown lengthening, the PMMA-based bone cement was prepared with gentamicin in a sterile surgical bowl. When the mixture stopped sticking to the surgical gloves, it was then positioned into the subnasal pit, under constant and copious saline irrigation. With the cement in place, the prosthesis was shaped in a maximum thickness of 7-mm. After complete polymerization and under abundant cooling, refinement and finishing of the PMMA prosthesis was performed. The prosthesis was fixed onto the bone with two titanium-based bone graft fixation screws. The smile aesthetic rehabilitation was complemented using 10 lithium disilicate-based ceramic veneers.

Discussion and conclusion

PMMA-based bone cement proved effective when combined to clinical crown lengthening for esthetic smile rehabilitation, acting as a filling material for subnasal depression, providing new lip support.

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

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

It Is Time to Reduce Free-Hand Manipulation: Case Report of Our Proposal for an Innovative 1-Step Cranioplasty

BACKGROUND

Cranioplasty is a well-known procedure, and autologous graft bone is usually considered the best choice in this procedure, but it cannot be used in conditions such as bone-infiltrating tumors, spheno-orbital en plaque meningiomas, and bone infections. Polymethylmethacrylate (PMMA) offers great possibility of intraoperative adaption. We describe a case of 1-step cranioplasty performed in a patient with a meningeal fibrosarcoma using a custom-made silicon mold.

CASE DESCRIPTION

A 48-year-old man was admitted to our department for a left temporo-parietal subcutaneous tumefaction that grew for a few months on the site of a previous osteodural decompression. After a biopsy that was diagnostic for meningeal fibrosarcoma, we planned tumor asportation, considering the bone infiltration of the tumor and the necessity of a cranioplasty. Before the intervention, we performed the craniotomy on a gypsum powder head phantom created based on a computed tomography scan. Then, using a computer-assisted design technique, a silicon mold was created and sterilized for the intervention. The edges of the preoperative simulated craniectomy were reproduced during the intervention using a rigid rail on the patient's scalp. The craniectomy was performed, and the tumor was removed. Then, a PMMA bone flap was made using a silicon mold and was fixed to the skull by miniscrews. Aesthetic results were considered excellent by the patient.

CONCLUSIONS

We performed a 1-step cranioplasty after resection of a meningeal fibrosarcoma that infiltrated bone with a new technique to reproduce during intervention a preoperative simulated craniectomy and a computer-assisted design PMMA flap.