Cranial repair: how complicated is filling a "hole"?

The role of autologous bone in cranioplasty. A systematic review of complications and risk factors by using stored bone

BACKGROUND

Autologous bone cranioplasty is associated with a high complication rate, particularly infections and bone resorption. Although there are studies on the incidence and risk factors for complications following autologous bone cranioplasty, the study design is typically limited to retrospective analysis with multiple statistical explorations in small cohorts from single centers. Thus, there is a need for systematic analysis of aggregated data to determine the rate and risk factors for cranioplasty complications.

OBJECTIVE

To determine the incidence and risk factors for complications after autologous bone cranioplasty.

METHODS

In this systemic review, we conducted a Medline, Embase, Cochrane, and Web of Science search: 11,172 papers were identified. Duplicates were removed and only articles on complications following autologous bone cranioplasty between the years 2000 and 2022 were included. After title, abstract, and article screening, 132 papers were included for further analysis.

RESULTS

In total, the 132 studies are based on 13,592 patients (14960 implants). One third of the studies include patients with less than 3 months of postoperative follow-up. Complication management (flap removal, revision without flap removal, and conservative treatment) of infection, bone resorption, and hematoma/seromas are not reported in 19-30% of the studies. In the studies with defined complications management, the overall complication rate is 7.6% (95% Confidence Interval (CI) [7.1-8.2]) for infection, 14.4% (95% CI [13.7-15.2]) for bone resorption with indication for reconstruction, and 5.8%, (95% CI 5.2-6.5) for hematoma/seromas. Factors such as younger age, an extended interval between craniectomy and cranioplasty, the use of a fragmented bone implant, a larger implant size, and shunt treatment are linked to an increased risk of postoperative bone resorption.

CONCLUSION

The lack of consistent definitions of complications, variations in follow-up time, and small study cohorts limit the external validity of many studies. Overall, the rate of bone flap resorption that required reoperation is high, while the rate of infectious complications is comparable to synthetic implants. Thus, autologous bone should preferably be used in cases without strong risk factors for bone necrosis.

Complication rates after autologous cranioplasty following decompressive craniectomy

OBJECTIVE

The reimplantation of autologous bone grafts after decompressive craniectomy (DC) is still up for debate. The objective of this study was to analyze the surgical revision rate for autologous cranioplasties in our center, aiming to identify predictors for procedure-related-complications.

METHODS

A retrospective single-center study was conducted for adult patients who underwent autologous cranioplasty after DC. The primary endpoint was the complication rate in terms of surgical revision and removal of the bone graft: infection, new onset seizures, dislocation, haemorrhage, osteolysis, wound dehiscence and cerebrospinal fluid (CSF) fistula. Demographic data, medical records, surgical reports and imaging studies were analysed and risk factors for complications were evaluated.

RESULTS

169 consecutive patients were included. The median interval between DC and cranioplasty was 84 days. Mean age was 51 ± 12.4 years. 26 patients (15.3%) had revision surgery for following reasons. n = 9 implant dislocations (5.3%), n = 7 osteolysis (3.6%), n = 6 infections (3.6%), n = 5 had re-bleedings (3%), n = 5 wound dehiscences (3%), and n = 2 CSF fistulas (1.2%). 18 patients developed new seizures (10.7%). Bi- and multivariate analysis revealed three independent risk factors, simultaneous ventriculo-peritoneal (VP) shunting increased the risk for material dislocation (p < 0.001); large bone grafts (> 193.5 cm2) increased the risk for osteolysis (p = 0.001) and bifrontal cranioplasties were associated with higher risk for infections (p = 0.04).

CONCLUSION

The complication rates in our study were comparable to previously reported data for autologous or artificial cranioplasties. As osteolysis was correlated to larger bone grafts, a synthetic alternative should be considered in selected cases.

Optimal Timing of Cranioplasty After Decompressive Craniectomy: Timing or Collapse Ratio

BACKGROUND AND OBJECTIVES

Although cranioplasty (CP) is a relatively straightforward surgical procedure, it is associated with a high complication rate. The optimal timing for this surgery remains undetermined. This study aimed to identify the most suitable timing for CP to minimize postoperative complications.

METHODS

We conducted a retrospective analysis of all CP cases performed in our department from August 2015 to March 2022. Data were gathered through case statistics and categorized based on the occurrence of complications. The collapse ratio was determined using 3-dimensional Slicer software.

RESULTS

In our retrospective study of 266 patients, 51 experienced postoperative complications, including hydrocephalus, epidural effusion, subdural hematoma, epilepsy, and subcutaneous infection. Logistic regression analysis identified independent predictors of postcranioplasty complications, and a nomogram was developed. The predictive value of the logistic regression model, collapse ratio, and decompression craniotomy-CP operation interval for post-skull repair complications was assessed using receiver operating characteristic curve analysis. No significant differences were observed in postoperative complications and decompression craniotomy-CP intervals between the groups (P = .07, P > .05). However, significant differences were noted in postoperative collapse ratios and CP complications between the groups (P = .023, P < .05). Logistic regression revealed that the collapse ratio (odds ratio = 1.486; 95% CI: 1.001-2.008; P = .01) and CP operation time (odds ratio = 1.017; 95% CI: 1.008-1.025, P < .001) were independent risk factors for postoperative complications. Receiver operating characteristic curve analysis indicated that the collapse ratio could predict CP postoperative complications, with a cutoff value of 0.274, an area under the curve of 0.621, a sensitivity of 62.75%, and a specificity of 63.26%.

CONCLUSION

The post-skull repair collapse ratio is a significant predictor of postoperative complications. It is advisable to base the timing of surgery on the extent of brain tissue collapse, rather than solely on the duration between cranial decompression and CP.

Bone Flap Resorption After Cranioplasty: Risk Factors and Proposal of the Flap Integrity Score

BACKGROUND

Bone flap resorption is a known complication of postdecompressive autologous cranioplasty. Although several potential etiopathogenetic factors have been investigated, their role is still under discussion. To further complicate things, resorption is not an all-or-nothing event, patients frequently presenting with different degrees of flap remodeling. Focus of this paper was to describe the elaboration of a score quantifying bone resorption according to a set of clinical and radiological criteria, hopefully allowing prompt identification of patients needing resurgery before the development of adverse events.

METHODS

In a 10-year period, 281 autologous cranioplasties were performed at our institution following decompressive craniectomy. Pertinent clinical and radiological information was registered. A set of 3 clinical and 3 radiological parameters was established to score the degree of resorption, identified under the acronym FIS (Flap Integrity Score). Three groups of patients emerged, respectively showing no (208), partial (32), and advanced (41) resorption.

RESULTS

An overall 14.6% incidence of advanced bone resorption was found in our series. Younger age, bone multifragmentation, higher postcranioplasty Glasgow Outcome Scale scores, <2 cm distance of medial craniectomy border from the midline, and cause leading to decompressive craniectomy were associated to a statistically significant higher risk of developing a relevant bone flap resorption. The first three variables were confirmed as risk factors in multivariate analysis. Flap Integrity Score well discriminated the 3 different groups.

CONCLUSIONS

Autologous bone repositioning is still a valuable, low-cost, cosmetically and functionally satisfactory procedure. Nonetheless, although resorption affects a minor percentage of patients, its early identification and treatment can improve long-term results.

Breaking Barriers in Cranioplasty: 3D Printing in Low and Middle-Income Settings-Insights from Zenica, Bosnia and Herzegovina

Background and Objectives: Cranial defects pose significant challenges in low and middle-income countries (LIMCs), necessitating innovative and cost-effective craniofacial reconstruction strategies. The purpose of this study was to present the Bosnia and Herzegovina model, showcasing the potential of a multidisciplinary team and 3D-based technologies, particularly PMMA implants, to address cranial defects in a resource-limited setting. Materials and Methods: An observational, non-experimental prospective investigation involved three cases of cranioplasty at the Department of Neurosurgery, Cantonal Hospital Zenica, Bosnia and Herzegovina, between 2019 and 2023. The technical process included 3D imaging and modeling with MIMICS software (version 10.01), 3D printing of the prototype, mold construction and intraoperative modification for precise implant fitting. Results: The Bosnia and Herzegovina model demonstrated successful outcomes in cranioplasty, with PMMA implants proving cost-effective and efficient in addressing cranial defects. Intraoperative modification contributed to reduced costs and potential complications, while the multidisciplinary approach and 3D-based technologies facilitated accurate reconstruction. Conclusions: The Bosnia and Herzegovina model showcases a cost-effective and efficient approach for craniofacial reconstruction in LIMICs. Collaborative efforts, 3D-based technologies, and PMMA implants contribute to successful outcomes. Further research is needed to validate sustained benefits and enhance craniofacial reconstruction strategies in resource-constrained settings.

A 2-Year Prospective Study of Complication Rates After Cranioplasty: Is 8 Weeks' Interval Associated with Increased Complications?

BACKGROUND

The commonly observed complications after cranioplasty include infections, intracranial hemorrhage, and seizures. The timing of cranioplasty after decompressive craniectomy (DC) is still under debate, with literature available for both early and delayed cranioplasties. The objectives of this study were to note the overall complication rates and more specifically compare complications between 2 different time intervals.

METHODS

This was a 24-month, single-center, prospective study. Since timing is the most debated variable, the study cohort was divided into 2 groups (≤8 weeks and >8 weeks). Furthermore, other variables such as age, gender, etiology of DC, neurologic condition, and blood loss were correlated with complications.

RESULTS

A total of 104 cases were analyzed. Two thirds were traumatic etiology. The mean and median DC-cranioplasty intervals were 11.3 weeks (range 4-52 weeks) and 9 weeks, respectively. Seven complications (6.7%) were observed in 6 patients. There was no statistical difference observed between any of the variables and complications.

CONCLUSIONS

We observed that performing cranioplasty within 8 weeks of the initial DC surgery is safe and noninferior to cranioplasty performed after 8 weeks. Therefore if the general condition of the patient is satisfactory, we are of the opinion that an interval of 6-8 weeks from the primary DC is safe and a reasonable time frame for performing cranioplasty.

Development of 3D printed patient-specific skull implants based on 3d surface scans

Sometimes cranioplasty is necessary to reconstruct skull bone defects after a neurosurgical operation. If an autologous bone is unavailable, alloplastic materials are used. The standard technical approach for the fabrication of cranial implants is based on 3D imaging by computed tomography using the defect and the contralateral site. A new approach uses 3D surface scans, which accurately replicate the curvature of the removed bone flap. For this purpose, the removed bone flap is scanned intraoperatively and digitized accordingly. When using a design procedure developed for this purpose creating a patient-specific implant for each bone flap shape in short time is possible. The designed skull implants have complex free-form surfaces analogous to the curvature of the skull, which is why additive manufacturing is the ideal manufacturing technology here. In this study, we will describe the intraoperative procedure for the acquisition of scanned data and its further processing up to the creation of the implant.

Surgery for Malignant Acute Ischemic Stroke: A Narrative Review of the Knowns and Unknowns

Malignant acute ischemic stroke (AIS) is characterized by acute neurological deterioration caused by progressive space-occupying brain edema, often occurring in the first hours to days after symptom onset. Without any treatment, the result is often fatal. Despite advances in treatment for AIS, up to 80% of patients with a large hemispheric stroke or cerebellar stroke are at risk of poor outcome. Decompressive surgery can be life-saving in a subgroup of patients with malignant AIS, but uncertainties exist on patient selection, predictors of malignant infarction, perioperative management, and timing of intervention. Although survivors are left disabled, most agree with the original decision to undergo surgery and would make the same decision again. In this narrative review, we focus on the clinical and radiological predictors of malignant infarction in AIS and outline the technical aspects of decompressive surgery as well as duraplasty and cranioplasty. We discuss the current evidence and recommendations for surgery in AIS, highlighting gaps in knowledge, and suggest directions for future studies. KEY POINTS: · Acute ischemic stroke from occlusion of a proximal intracranial artery can progress quickly to malignant edema, which can be fatal in 80% of patients despite medical management.. · Decompression surgery is life-saving within 48 hours of stroke onset, but the benefits beyond this time and in the elderly are unknown.. · Decompressive surgery is associated with high morbidity, particularly in the elderly. The decision to operate must be made after considering the individual's preference and expectations of quality of life in the context of the clinical condition.. · Further studies are needed to refine surgical technique including value of duraplasty and understand the role monitoring intracranial pressure during and after decompressive surgery.. · More studies are needed on the pathophysiology of malignant cerebral edema, prediction models including imaging and biomarkers to identify which subgroup of patients will benefit from decompressive surgery.. · More research is needed on factors associated with morbidity and mortality after cranioplasty, safety and efficacy of implants, and comparisons between them.. · Further studies are needed to assess the long-term effects of physical disability and quality of life of survivors after surgery, particularly those with severe neurological deficits..

How much space is needed for decompressive surgery in malignant middle cerebral artery infarction: Enabling single-stage surgery

Introduction

Decompressive hemicraniectomy (DCE) is routinely performed for intracranial pressure control after malignant middle cerebral artery (MCA) infarction. Decompressed patients are at risk of traumatic brain injury and the syndrome of the trephined until cranioplasty. Cranioplasty after DCE is itself associated with high complication rates. Single-stage surgical strategies may eliminate the need for follow-up surgery while allowing for safe brain expansion and protection from environmental factors.

Research question

Assess the volume needed for safe expansion of the brain to enable single-stage surgery.

Materials and methods

We performed a retrospective radiological and volumetric analysis of all patients that had DCE in our clinic between January 2009 and December 2018 and met inclusion criteria. We investigated prognostic parameters in perioperative imaging and assessed clinical outcome.

Results

Of 86 patients with DCE, 44 fulfilled the inclusion criteria. Median brain swelling was 75.35 mL (8.7-151.2 mL). Median bone flap volume was 113.3 mL (73.34-146.1 mL). Median brain swelling was 1.62 mm below the previous outer rim of the skull (5.3 mm to -2.19 mm). In 79.6% of the patients, the volume of removed bone alone was equivalent to or larger than the additional intracranial volume needed for brain swelling.

Discussion and conclusion

The space provided by removal of the bone alone was sufficient to match the expansion of the injured brain after malignant MCA infarction in the vast majority of our patientsA subgaleal space-expanding flap with a minimal offset can provide protection from trauma and atmospheric pressure without compromising brain expansion.

Complications of Different Types of Cranioplasty and Identification of Risk Factors Associated with Cranioplasty at a Tertiary Care Centre: A Prospective Observational Study

Objective Decompressive craniectomy (DC) is an urgent procedure which is done to decrease intracranial pressure. A study of the complications would suggest measures to improve the care. This study was focused on analyzing the complications after cranioplasty (CP) and to identify risk factors that may be associated with the failure of the procedure.

Method: This study was conducted over 41 months at level-1 trauma center and medical college. It included patients undergoing CP for a defect arising out of previous DC or inability to replace the bone flap (Glasgow Coma Scale > 13, size > 5 cm, without surgical site infection). All patients underwent CT imaging before and after the procedure. The CP technique largely depended on the patients, based on the cost of prosthesis and availability.

Result: Hundred patients were included in the study. Postoperatively, total 22 patients suffered complications of which few had more than one complication. Titanium implant appeared to be a better implant, with no complication (p < 0.05). Complication was common in younger age group, chemically cured PMMA (polymethyl methacrylate) and ethylene oxide) sterilized bone flap). Complications were higher among patients with multiple comorbidity and stroke patients.

Conclusion: Titanium flap had no complication and in case of autologous abdominal subcutaneous flap, apart from bone flap absorption, patients had no major complication. Therefore, both implants are preferred implants for CP. Heat-cured PMMA can be used in case of nonavailability of a better option, as it is economical feasible and can be molded at any dental lab.

Outcomes of Cranioplasty: A Single-Center Experience

Background Cranioplasty (CP) is a common cranial reconstructive procedure. It is performed after craniectomy due to various causes such as relieving increased intracranial pressure, infection, and tumor infiltration. Although CP is an easy procedure, it is associated with a high rate of complications. We aimed to retrospectively investigate the outcomes of CP at the King Abdulaziz Medical City, Ministry of National Guard Health Affairs, Jeddah (KAMC-J). Methods This is a retrospective observational study that included all patients who had CP (first time or redo) at KAMC-J from 1st January 2010 to 31st December 2020. Patients with congenital cranial malformation were excluded.  Result A total of 68 patients underwent CP. Of those, 23 (34%) had complications. The most common complication was infection (10.3%). Twelve of the 23 patients had major complications that necessitated reoperation. Of those 12, six underwent redo CP; three out of these six patients had further complications which were also managed surgically. On bivariate analysis, cranial defects over 50 cm² were associated with a higher rate of both infection and hydrocephalus (p=0.018) while the frontal site was associated with a higher rate of infection (p=0.014). Moreover, traumatic brain injury as an etiology was exclusively associated with post-cranioplasty hydrocephalus (p=0.03).  Conclusion Patients undergoing CP after craniectomy are prone to a considerably high rate of adverse outcomes. The overall rate of complications in this study was 34%, with an infection rate of 10.3% and a 1.5% mortality rate. Consistent with other studies, larger cranial defects as well as frontal sites have a higher rate of infection.

Predictors of Clinical Outcomes in Autologous Cranioplasty

BACKGROUND

Cranioplasty is a common neurosurgical procedure and autologous grafts are preferred due to their aesthetic and biocompatibility benefits. Multiple risk factors are implicated as predictors for neurologic outcome. This study focuses on risk factors that may be associated with complications and analyzes the predictors of neurologic outcomes after autologous cranioplasty.

METHODS

This is a retrospective observational study conducted at a tertiary care center between 2015 and 2021. Adults with autologous cranioplasty (n = 132) were recruited from procedure logs and the hospital electronic health record. Clinicodemographic parameters, risk factors, and complications were recorded. Neurologic outcomes were measured using the dichotomized Glasgow Outcome Scale (GOS). Primary outcome measure was pre- and post-cranioplasty GOS at the last follow up. Secondary outcome measures were the predicting factors that contributed to enhanced neurologic outcome post-cranioplasty.

RESULTS

Mean age was 41.4 (standard deviation ± 13.5) years with male predominance (12.2:1). Complications developed in 12.9% (n = 17), with infections in 3.8% (n = 5) and hydrocephalus in 2.3% (n = 3). In bivariate analysis, pre-cranioplasty GOS good grades 4 and 5 (P < 0.001), trauma as an indication for decompressive craniectomy (DC) (P < 0.001), and early cranioplasty ≤12 weeks (P = 0.023) were statistically significant predictors for post-cranioplasty neurologic recovery at follow-up. In a multiple logistic regression model, adjusted odds ratio for pre-cranioplasty GOS was 28.77 (95% confidence interval [CI] 7.21-114.74, P < 0.001), for trauma as indication for DC was 5.15 (95% CI 1.65-16.05, P = 0.003), and for early cranioplasty ≤12 weeks was 3.04 (95% CI 1.12-8.27 P = 0.029).

CONCLUSIONS

Autologous cranioplasty contributes to a quantifiable neurologic outcome. Pre-cranioplasty neurologic status, cranioplasty done for traumatic DC and early cranioplasty may have potential for enhanced neurologic recovery. Further clinical studies with better evidence may expound upon these findings.

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

Background

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

Objective

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

Methods

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

Results

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

Conclusions

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

Trial Registration

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

International Registered Report Identifier (IRRID)

DERR1-10.2196/36111

Outcomes of Cranioplasty Strategies for High-Risk Complex Cranial Defects: A 10-Year Experience

INTRODUCTION

Although the literature contains reports of the risks and complications of calvarial vault reconstruction for acquired defects, there are few publications addressing the specific patient population who require such reconstructions in cases preceded by prior infection, radiation, massive associated soft tissue trauma, and so on. We define such clinical presentations as a hostile environment for large surface area reconstruction. Our objective is to compare the safety and efficacy of autologous bone and alloplastic reconstruction in hostile cranial defects.

METHODS

An institutional review board-approved retrospective review of patients who underwent cranioplasty of a hostile site at the University of Alabama at Birmingham between January 2008 and December 2018 was performed. The patients were stratified into 3 groups based on the type of implant used: autogenous (bone), alloplastic (polyetheretherketone [PEEK], titanium, polymethyl methacrylate), or mixed (combination of bone and prosthetic). The primary outcome metric was a complication in the year after cranioplasty, identified by implant failure, necrosis, or infection. Statistical analysis included t tests and χ2 tests where appropriate using SPSS.

RESULTS

There were 55 total cases in this period: 27 autogenous, 23 alloplastic, and 5 mixed. The purely autogenous group had the highest complication rate (44%), and the alloplastic group had the lowest complication rate (38%), which was not statistically different between the 3 groups (P = 0.121). When stratified by specific material used for reconstruction (27 bone, 14 PEEK, 10 titanium, and 5 polymethyl methacrylate), overall complication rate was statistically significant (P = 0.009, χ2 test), with PEEK implants having the lowest complication rate (21%).

CONCLUSIONS

This analysis interestingly found that in the setting of hostile cranial defects, cranioplasties would benefit from the use of prosthetic implants instead of autologous bone grafts, not only for avoidance of donor site morbidity but also for a decrease in overall complications.

Cranioplasty: A Multidisciplinary Approach

Decompressive craniectomy (DC) is an operation where a large section of the skull is removed to accommodate brain swelling. Patients who survive will usually require subsequent reconstruction of the skull using either their own bone or an artificial prosthesis, known as cranioplasty. Cranioplasty restores skull integrity but can also improve neurological function. Standard care following DC consists of the performance of cranioplasty several months later as historically, there was a concern that earlier cranioplasty may increase the risk of infection. However, recent systematic reviews have challenged this and have demonstrated that an early cranioplasty (within three months after DC) may enhance neurological recovery. However, patients are often transferred to a rehabilitation unit following their acute index admission and before their cranioplasty. A better understanding of the pathophysiological effects of cranioplasty and the relationship of timing and complications would enable more focused patient tailored rehabilitation programs, thus maximizing the benefit following cranioplasty. This may maximise recovery potential, possibly resulting in improved functional and cognitive gains, enhancement of quality of life and potentially reducing longer-term care needs. This narrative review aims to update multi-disciplinary team regarding cranioplasty, including its history, pathophysiological consequences on recovery, complications, and important clinical considerations both in the acute and rehabilitation settings.

A Retrospective Study of Complications in Cranioplasty: 7-Year Period

Objective

To discuss the intraoperative and postoperative complications of cranioplasty and management during a 7-year period.

Method

Retrospective study of 7-year period of 63 patients including both male and female.

Results

Highest experienced complications were seizures and dural tear, i.e., 6%, followed by EDH in 3% patients, hydrocephalus and pneumocephalus combined 3%, 1.6% CSF collection and flap necrosis each. All the complications were managed successfully.

Conclusion

Complications of cranioplasty can be managed by following sound surgical principles. Serious complications like meningitis, air embolism and death are rare.

Direct Consequences of Cranioplasty to the Brain: Intracranial Pressure Study

ABSTRACT

Intracranial pressure (ICP) is a crucial factor that we need to take into account in all major pathophysiological changes of the brain after decompressive craniectomy (DC) and cranioplasty (CP). The purpose of our study was to check ICP values before and after cranioplasty and its relation to various parameters (imaging, demographics, time of cranioplasty, and type of graft) as well as its possible relation to postsurgical complications. The authors performed a prospective study in which they selected as participants adults who had undergone unilateral frontotemporoparietal DC and were planned to have cranioplasty. Intracranial pressure was measured with optical fiber sensor in the epidural space and did not affect cranioplasty in any way.Twenty-five patients met the criteria. The mean vcICP (value change of ICP) was 1.2 mm Hg, the mean ΔICP (absolute value change of the ICP) was 2.24 mm Hg and in the majority of cases there was an increase in ICP. The authors found 3 statistically significant correlations: between gender and ΔICP, Δtime (time between DC and CP) and vcICP, and pre-ICP and ±ICP (quantitative change of the ICP).Μale patients tend to develop larger changes of ICP values during CP. As the time between the 2 procedures (DC and CP) gets longer, the vcICP is decreased. However, after certain time it shows a tendency to remain around zero. Lower pre-ICP values (close to or below zero) are more possible to increase after bone flap placement. It seems that the brain tends to restore its pre-DC conditions after CP by taking near-to-normal ICP values.

A Multilayered Dural Repair Technique Using Duragen for Early Cranioplasty Following Decompressive Craniotomy

Decompressive craniotomy is a neurosurgical emergency procedure in which a large skull bone is removed and the dura matter is extensively opened. Duraplasty is required to avoid cerebrospinal fluid (CSF) leakage during the decompressive craniotomy. DuraGen® is a safe and effective type I collagen matrix graft, which is frequently used in decompressive craniotomy procedures. Since DuraGen® does not require labor-intensive suturing, the operative time is shortened by DuraGen® closure with sufficient tightness preventing CSF leakage. Recently, early cranioplasty is preferred to achieve efficient rehabilitation after decompressive craniotomy. Although evidence of efficacy and safety of DuraGen® has been increasing in the management of duraplasty, no reports have previously discussed the condition of DuraGen® during the second surgery (cranioplasty) at this early timing. DuraGen®-derived neodura develops a mature dura 1 year post its placement, and the neodura remain fragile at this early time point. A deconstructed fragile neodura may result in postoperative CSF leakage. Here, we illustrated a multilayered dural repair technique with DuraGen® to avoid disruption of the fragile neodura during early cranioplasty.

Diversifying the rehabilitation of calvarial defects: Rejuvenating precision: A case series

Cranial vault defects are either congenital or acquired in origin. Cranioplasty is most commonly done in patients after trauma, decompressive craniectomies, tumor resections, infections or because of congenital malformations. The purpose of a Cranioplast is to protect the underlying brain tissues, reduce pain, and to improve the calvarial contour, symmetry, and esthetics. Rehabilitation of these defects possesses a challenge to the surgical team and prosthodontist. With advancement in three-dimensional (3D) engineering technology, the use of rapid prototyping technology (RPT) can be used in the fabrication of 3D skull eliminating conventional impression for recording defect region. Custom-made cranial prosthesis now can be fabricated using the conventional method of wax-up and lost-wax method. Case 1 had a history of road traffic accident followed by decompressive craniectomy, which led to frontoparietotemporal defect of the right side. The 3D model was fabricated using RPT technology. The wax pattern fabricated on 3D prototyped skull was contoured using digital photographic superimposition method. Case 2 had a history of trauma on the head causing intracerebral hemorrhage followed by decompressive craniectomy which led to frontoparietotemporal defect of the right side. The 3D model was fabricated using RPT. The wax pattern fabricated on 3D prototyped skull was contoured using the compass method. The use of these methods with the added advantage of RPT resulted in prosthesis with good esthetics and better fit. The contour of the prosthesis was replicated in the same manner as compared to the contralateral side. These techniques are easy to use and are less time consuming and had few chances of errors.

Bone flap management strategies for postcraniotomy surgical site infection

Background:

Surgical site infection (SSI) after a craniotomy is traditionally treated with wound debridement and disposal of the bone flap, followed by intravenous antibiotics. The goal of this study is to evaluate the safety of replacing the bone flap or performing immediate titanium cranioplasty.

Methods:

All craniotomies at single center between 2008 and 2020 were examined to identify 35 patients with postoperative SSI. Patients were grouped by bone flap management: craniectomy (22 patients), bone flap replacement (seven patients), and titanium cranioplasty (six patients). Retrospective chart review was performed to identify patient age, gender, index surgery indication and duration, diffusion restriction on MRI, presence of gross purulence, bacteria cultured, sinus involvement, implants used during surgery, and antibiotic prophylaxis/ treatment. These variables were compared to future infection recurrence and wound breakdown.

Results:

There was no significant difference in infection recurrence or future wound breakdown among the three bone flap management groups (P = 0.21, P = 0.25). None of the variables investigated had any significant relation to infection recurrence when all patients were included in the analysis. However, when only the bone flap replacement group was analyzed, there was significantly higher infection recurrence when there was frank purulence present (P = 0.048).

Conclusion:

Replacing the bone flap or performing an immediate titanium cranioplasty is safe alternatives to discarding the bone flap after postoperative craniotomy SSI. When there is gross purulence present, caution should be used in replacing the bone flap, as infection recurrence is significantly higher in this subgroup of patients.

Post-Cranioplasty Complications: Lessons From a Prospective Study Assessing Risk Factors

ABSTRACT

Complication rate related with cranioplasty is described as very high in most of relevant studies. The aim of our study was to try to identify possible factors, that could predict complications following cranioplasty. The authors hypothesized that some physical characteristics on the preoperative brain computed tomography (CT) scan can be predictive for complications.The authors carried out a prospective observational study. All patients were adults after decompressive craniectomy, planned for cranioplasty and had a brain CT scan the day before cranioplasty. Our data pool included demographics, reason of craniectomy, various radiological parameters, the time of cranioplasty after craniectomy, the type of cranioplasty bone flap, and the complications.Twenty-five patients were included in the study. The authors identified statistically significant correlation between time of cranioplasty after craniectomy and the complications, as well as between the type of cranioplasty implant and the complications. There was statistically significant correlation between complications and the distance of the free brain surface from the level of the largest skull defect dimension - free brain surface deformity (FBSD). Moreover, the correlation between FBSD and the time of cranioplasty was statistically significant.It seems that for adult patients with unilateral DC the shorter time interval between craniectomy and cranioplasty lowers the risk for complications. The risk seems to be decreased further, by using autologous bone flap. Low values of the FBSD increase the risk for complications. This risk factor can be avoided, by shortening the time between craniectomy and cranioplasty.

Cranioplasty with Autologous Bone Flaps Cryopreserved with Dimethylsulphoxide: Does Tissue Processing Matter

OBJECTIVE

The aim of this article was to study the outcome of patients who underwent cranioplasty with cryopreserved autologous bone after decompressive craniectomy.

METHODS

Data from 74 patients were retrospectively analyzed. They were divided into groups according to the storage time and the age at cranioplasty. To assess the predictive potential for complication, factors were related to successive stages (preoperative, craniectomy, tissue processing, cranioplasty, and postoperative). Cooling and warming rates applied on bone flap were calculated. The ability to inhibit microbial growth was determined exposing bone fragments to a panel of microorganisms. The concentration of antibiotics eluted from the bone was also determined. A bone explant culture method was used to detect living cells in the thawed cranial bone.

RESULTS

Hydrocephalus was significantly more frequent in pediatric patients (26.7%) than in adults (5.1%). The overall rate of bone flap resorption was 21.6% (43.7% of which required reoperation). Surgical site infection after cranioplasty was detected in 6.8% of patients. There was no correlation between infection as a postoperative complication and previous microbiological-positive culture during processing. The cause of craniectomy did not influence the risk of bone flap contamination. Vancomycin was the only antibiotic detected in the supernatant where the bone was incubated. Outgrowth from bone explants was observed in 36.8% of thawed skulls. An early start of bone flap processing at the tissue bank had a positive effect on cell viability.

CONCLUSIONS

The outcome after autologous cranioplasty is a multifactorial process, which is modulated by patient-related, surgery-related, and bone-related factors.

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.

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

Background:

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

Methods:

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

Results:

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

Conclusion:

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

Cranioplast fabrication in a comatose patient: A clinical report

Cranioplasty may be necessary after decompressive craniectomies to aid in the restoration of the esthetic, morphological, functional, and psychosocial stability of those affected. This clinical report describes the management of a comatose road traffic accident victim with a history of autogenous cranial implant failure after decompressive craniectomy. The challenges posed by the nonambulatory state of the patient and his inability to follow commands were overcome by using reverse engineering and rapid prototyping to fabricate a 3D patient-specific polymethylmethacrylate cranial implant. A digital evaluation technique with grids as measuring tools was successfully implemented in the patient's absence. The use of a custom clamp flask aided in the accommodation and subsequent investing, dewaxing, and polymerization of the carved cranial wax pattern. As a result, a custom cranioplast with optimum marginal fit, acceptable contour, adequate thickness, and reduced surgical duration of placement was obtained through a successful combination of conventional and digital techniques.

Establishment and Characteristic Analysis of a Dog Model for Autologous Homologous Cranioplasty

Objective

The aim of this study is to establish a large animal (dog) model that can be referred clinically for autologous homologous cranioplasty.

Methods

Our large skull defect dog model was established by emulating the decompressive craniectomy with 22 adult beagle dogs. The autologous bones were taken out from the dogs and divided into two groups, the freeze-drying (FD) group and the single freezing (SF) group. They were then stored in the bone bank at -20°C after being irradiated with 25 KGy. Three months later, the bones were reimplanted. After operation, we closely watch the experimental objects for four more months examining the infection and survival of the bone graft.

Results

Through macroscopic observation, it was found that, among 44 cranial flaps (bilateral) from the rest of the 22 dogs, grade A cranial flaps accounted for 86.4% (19/22) in the SF group and only 31.8% (7/22) in the FD group. Although osteogenic osteoclast, Harvard tube, neovascularization, and angiogenic factors were found through the pathological results, including an electron microscope and calmodulin tracer, it could be verified by using X-CT and micro-CT that early bone resorption could be still found even in grade A bone flap.

Conclusion

By using the common clinical method to preserve the cranial flaps, we established an experimental dog model of autologous cranioplasty for a large area of cranial defect. It was proved that this model could reproduce the infections and bone resorption which typically happened in clinical autologous homologous cranioplasty. As a conclusion, the established model can be used as an effective experimental tool for further research to improve the success rate of autologous homologous cranioplasty.

Comparative Cost-Effectiveness of Cranioplasty Implants

Purpose

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

Methods

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

Results

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

Conclusions

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

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.

Cranioplasty length of stay: Relationship with indication, surgical decision-making factors, and sex

Objectives

Cranioplasty is being performed more often due to rising rates of decompressive craniectomy. Hospital length of stay is a quality metric which has not been directly studied after cranioplasty. This study aims to identify factors associated with length of stay after cranioplasty to better understand their outcomes.

Patients and methods

A retrospective review was conducted at a single academic center from 2007 to 2015 for all patients >18 years of age who received cranioplasty. Baseline data from 148 patients were recorded including demographics, clinical characteristics, and surgeon decision-making factors for cranioplasty. Post-operative complications within 30 days after cranioplasty were recorded in addition to disposition and discharge data. Weibull accelerated failure time models were used to identify significant associations with length of stay after cranioplasty.

Results

The overall post-operative complication rate was 27.0%, and the most frequent indication for craniectomy was traumatic brain injury. The majority (72.3%) of patients returned home, compared to other disposition, and median length of stay was 2.0 days (interquartile range = 2.0). Average length of stay was 7.7 days in men, as compared with 2.4 days in women, and even upon adjusting for covariate effects, length of stay was longer in men than in women irrespective of post-operative complications. When time-to-cranioplasty fell between 0 and 30 days, average length of stay was 19.2 days, as compared with 10.3 days when time-to-cranioplasty fell between 30 and 90 days, and 2.5 days when time-to-cranioplasty was >90 days. After adjustment for covariate effects, the association between time-to-cranioplasty and length of stay was maintained only in patients without post-operative complications.

Conclusions

Length of stay can inform our understanding of outcomes after cranioplasty. In our study, length of stay was associated with sex, indication for craniectomy, and surgical decision-making (time-to-cranioplasty and implant material), but time-to-cranioplasty was only associated in patients without post-operative complications. These relationships should be seen not as direct causation, but rather as tools to add to our understanding of this relatively complicated procedure.

Autogenous Bone Cranioplasty: Review of a 42-Year Experience by a Single Surgeon

BACKGROUND

Autogenous bone is frequently espoused as the gold standard material for cranioplasty procedures, yet alloplastic cranioplasty continues to persist in the search, presumably, for a simpler technique. Although short-term outcomes can be successful using foreign materials, long-term follow-up in these patients often demonstrates increased rates of failure because of exposure or late infection. Autogenous bone grafts, however, integrate and revascularize, and are thus more resistant to infection than alloplastic materials.

METHODS

This is a retrospective review of all patients that underwent reconstructive cranioplasty for full-thickness defects, as performed by the senior author (S.A.W.) between 1975 and 2018. All procedures were performed with autogenous bone.

RESULTS

One hundred fifty-four patients met criteria for inclusion in the report. Cranioplasties were performed for both congenital and secondary indications. Split calvaria was used in 115 patients (74.7 percent), rib graft was used in 12 patients (7.8 percent), iliac crest graft was used in 10 patients (6.5 percent), and combinations of donor-site grafts were used in 17 patients (11.0 percent). In the entire series, none of the patients suffered from complications related to infection of either the donor site or transferred bone graft. None of the patients required secondary operations to fill in defects created by the postoperative resorption.

CONCLUSIONS

Although autologous bone is widely considered the gold standard material for cranioplasty procedures, some argue against its use, mainly citing unpredictable resorption as the purported disadvantage. However, it is less susceptible to infection, and results in fewer long-term complications than alloplastic materials. There is no alloplastic material that has matched these outcomes, and thus autogenous bone should be considered as the primary option for cranioplasty procedures.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

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

INTRODUCTION

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

EVIDENCE ACQUISITION

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

EVIDENCE SYNTHESIS

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

CONCLUSIONS

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

An investigation of factors associated with the development of postoperative bone flap infection following decompressive craniectomy and subsequent cranioplasty

OBJECTIVE

After a decompressive craniectomy (DC), a cranioplasty (CP) is often performed in order to improve neurosurgical outcome and cerebral blood circulation. But even though the performance of a CP subsequent to a DC has become routine medical practice, patients can in fact develop many complications from the surgery that could prolong hospitalization and lead to unfavorable prognoses. This study investigates one of the most frequent complications, bone flap infection, in order to identify prognostic factors of its development.

PATIENTS AND METHODS

In this single-center study, we have retrospectively examined 329 CPs performed between 2002 and 2017. Multiple categorical and metric parameters (e.g., timing of CP, bone flap material, specific laboratory signs of infection and reason for DC) were analyzed applying unadjusted and multivariable testing.

RESULTS

Bone flap infection occurred in 24 patients (7.3%). A CP performed more than six months after a DC is associated with a significantly increased risk of infection (OR = 0.308 [0.118; 0.803], p = 0.016). However, with CPs performed after twelve months, the incidence decreases, but without provable statistical impact. In addition, bone flap infection is strongly related to the neurological outcome and the material used for the skull implant, with the use of synthetic bone flaps leading to a marked increase in the rate of infection (p < 0.001).

CONCLUSIONS

This study supports the hypothesis that the risk of infection is higher the longer the elapsed time between DC and CP, especially if more than six months. Based on our results, the best DC-CP time frame for keeping the infection rate low is performing the CP within the first six months after the DC. In the event that the CP cannot be performed within the first six months, a CP performed twelve months or more after the DC seems to have a favorable outcome as well.

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.

Management and prevention of cranioplasty infections

BACKGROUND

Infection may complicate the outcome of cranial repair with significant additional morbidity, related to hospitalization, surgery and long antibiotic therapy, that may become even dramatic in case of multi-resistant germs and in particular in the paediatric population. Additionally, the economic costs for the health system are obvious. Moreover, surgical decisions concerning the timing of cranioplasty and choice of the material may be strongly affected by the risk of infection. Despite, management and prevention of cranioplasty infections are not systematically treated through the literature so far.

METHODS

We reviewed pertinent literature dealing with cranioplasty infection starting from the diagnosis to treatment options, namely conservative versus surgical ones. Our institutional bundle, specific to the paediatric population, is also presented. This approach aims to significantly reduce the risk of infection in first-line cranioplasty and redo cranioplasty after previous infection.

CONCLUSIONS

A thorough knowledge and understanding of risk factors may lead to surgical strategies and bundles, aiming to reduce infectious complications of cranioplasty. Finally, innovation in materials used for cranial repair should also aim to enhance the antimicrobial properties of these inert materials.

The growth of the neurocranium: literature review and implications in cranial repair

BACKGROUND

Postnatal growth of neurocranium is prevalently completed in the first years of life, thus deeply affecting the clinical presentation and surgical management of pediatric neurosurgical conditions involving the skull. This paper aims to review the pertinent literature on the normal growth of neurocranium and critically discuss the surgical implications of this factor in cranial repair.

METHODS

A search of the electronic database of Pubmed was performed, using the key word "neurocranium growth", thus obtaining 217 results. Forty-six papers dealing with this topic in humans, limited to the English language, were selected. After excluding a few papers dealing with viscerocranium growth or pathological conditions not related to normal neurocranium growth 18 papers were finally included into the present review.

RESULTS AND CONCLUSIONS

The skull growth is very rapid in the first 2 years of life and approximates the adult volume by 7 years of age, with minimal further growth later on, which is warranted by the remodeling of the cranial bones. This factor affects the outcome of cranioplasty. Thus, it is essential to consider age in the planning phase of cranial repair, choice of the material, and critical comparison of results of different cranioplasty solutions.

Cranioplasty following decompressive craniectomy - Analysis of complication rates and neurological outcomes: A single center study

Background

Cranioplasty is the surgical intervention to repair cranial defects in both cosmetic and functional ways. Despite the fact that cranioplasty is a simple procedure, it is still associated with a relatively high complication rate, ranging between series from 12% to 50%.

Methods

The author did a prospective cohort study of patients from August 2015 to December 2017, who had undergone decompressive craniectomy followed by cranioplasty after 6 weeks at our institution. All patients were followed up to 6 months after cranioplasty and complications were recorded both by imaging and clinically. The complications were classified as minor (subgaleal collection, seizures) who did not require the second surgery and major (hydrocephalus, bone flap infection) who required the second surgery. To find out neurological outcome, Glasgow coma score (GCS) and Glasgow outcome scale extended (GOSE) were recorded at 1 month, 3 months, and 6 months.

Results

Overall complication rate in this study was 22.4% (16/72). Subgaleal collection was the most common complication (5.6%), followed by hydrocephalus (4.2%), seizure (4.2%), bone flap infection (2.8%), intracerebral hematoma (2.8%), empyema (1.4%), and subdural hematoma (SDH) (1.4%). Of these, 8.4% (n = 6/72) were major complication (hydrocephalus n = 3, bone flap infection n = 2, and SDH n = 1) which required the second surgery. GCS and GOSE were assessed preoperatively and in postoperative period at 1 month, 3 months, and 6 months. Both mean values of GCS and GOSE showed a significant improvement at 3 and 6 months after cranioplasty.

Conclusion

Cranioplasty after decompressive craniectomy is associated with higher complication rate, but good neurological outcome after surgery always outweighs the complications.

Key Message

Cranioplasty after decompressive craniectomy is associated with higher complication rate, but good neurological outcome after surgery always outweighs the complications. However, complications rate can be brought down by meticulous timing of cranioplasty in a patient of well-controlled comorbidities and precise surgical techniques. However, storing bone in bone bank is not an additional factor for any postcranioplasty complications which was considered previously.

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.

Postoperative Drain Use in Cranial Vault Remodeling: A Survey of Craniofacial Surgeon Practices and a Review of the Literature

BACKGROUND

The use of subgaleal drains following primary cranioplasty for craniosynostosis has undergone limited investigation. Proposed benefits include prevention of seroma, detection of postoperative bleeding, and cerebrospinal fluid leak. We conducted a systematic review of the literature and surveyed craniofacial surgeons to ascertain the current evidence pertaining to drain use following primary cranioplasty for craniosynostosis and to determine surgical practice patterns.

METHODS

PubMed and Embase databases were searched to identify relevant articles. Abstracts were reviewed by 2 investigators, and a Cohen κ statistic was calculated. Patient demographic and outcome data were extracted and compared. A 9-question survey was e-mailed to active and associate members of the American Society of Craniofacial Surgeons.

RESULTS

A total of 7395 unique citations were identified. Only 2 retrospective chart reviews met inclusion criteria. All objective parameters demonstrated no difference between patients with and without drains. A subjective benefit of limiting facial swelling was proposed without objective analysis. Fifty (32.5%) of the 154 craniofacial surgeons responded to the survey. Forty-two percent used postoperative drains. A significant association (P = .01) was found between the belief that drains limited facial swelling and their use.

CONCLUSIONS

The literature examining postoperative drain use in primary cranioplasty for craniosynostosis is restricted. The current studies show no definite benefit to drain use but are limited in their assessment of key outcomes. There is wide variability among surgeons regarding drain use, and this seems to be motivated by belief and tradition.

Bone resorption in autologous cryopreserved cranioplasty: quantitative evaluation, semiquantitative score and clinical significance

BACKGROUND

Changes after reimplantation of the autologous bone have been largely described. However, the rate and the extent of resorption in cranial grafts have not been clearly defined. Aim of our study is to evaluate the bone flap resorption (BFR) after cryopreservation.

METHODS

We retrospectively reviewed 27 patients, aged 18 years or older, subjected to cranioplasty (CP) adopting autologous cryopreserved flap. The BFR was derived from the percentage of decrease in flap volume (BFR%), comparing the first post-operative computed tomography (CT) and the last one available (performed at least 1 year after surgery). We also proposed a semiquantitative scoring system, based on CT, to define a clinically workable BFR classification.

RESULTS

After a mean ± SE follow-up of 32.5 ± 2.4 months, the bone flap volume decreased significantly (p < 0.0001). The mean BFR% was 31.7 ± 3.8% and correlated with CT-score (p < 0.001). Three BFR classes were described: mild (14.8% of cases) consisting in minimal bone remodelling, CT-score ≤ 6, mean BFR% = 3.5 ± 0.7%; moderate (51.9% of cases) corresponding to satisfactory cerebral protection, CT-score < 13, mean BFR% = 25.6 ± 2.2%; severe (33.3% of cases) consisting in loss of cerebral protection, CT-score ≥ 13, mean BFR% = 54.2 ± 3.9%. Females had higher BFR% than males (p = 0.022). BFR classes and new reconstructive surgery were not related (p = 0.58).

CONCLUSIONS

BFR was moderate or severe in 85.2% of re-implanted cryopreserved flaps. The proposed CT-score is an easy and reproducible tool to define resorption extent.

Complications of Cranioplasty

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

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

Background:

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

Methods:

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

Results:

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

Conclusion:

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

Early or late cranioplasty following decompressive craniotomy for traumatic brain injury: A systematic review and meta-analysis

Objective To evaluate the effectiveness of early (<3 months) cranioplasty (CP) and late CP (>3 months) on post-operative complications in patients receiving decompressive craniotomy (DC) for traumatic brain injury (TBI). Methods The Cochrane Library, PubMed and EMBASE databases were systematically searched for studies published prior to May 21, 2017. A meta-analysis examined post-operative overall complication rates, infection rates, subdural fluid collection and operating times according to early and late CP. Results Of the initial 1675 references, five studies, all cohort, involving a total of 413 patients, were selected for the review. There was no difference between early and late CP in post-operative overall complication rate (RR=0.68, 95%CI [0.36, 1.29]) and the post-operative infection rate (RR=0.50, 95%CI [0.20, 1.24]) in patients receiving DC for TBI. However, there was a significant difference in post-operative subdural effusion (RR=0.24, 95%CI [0.07, 0.78]) and mean operative time (mean difference = -33.02 min, 95%CI [-48.19, -17.84]) both in favour of early CP. Conclusions No differences were found between early and late CP in post-operative overall complications and procedural related infections in patients receiving DC for TBI, but early CP reduced the complication of subdural effusion and the mean operating time. These findings need to be confirmed by large, randomised controlled trials.