Cranioplasty Outcomes and Analysis of the Factors Influencing Surgical Site Infection: A Retrospective Review of More than 10 Years of Institutional Experience

[Role of cranioplasty in the management of decompressive craniectomies: Study of the Adolphe de Rothschild Foundation Hospital cohort over 7 years]

OBJECTIVES

The objective of our study is to take stock of the cranioplasty implants used within our establishment.

MATERIALS AND METHOD

We analyzed the patients files who underwent craniectomy followed by cranioplasty between 2017 and 2023, with at least 1 year of follow-up after cranioplasty (n=75). The data were extracted from the computerized patient file (DxCare®, Dédalus) and the pharmaceutical management tool for drugs and sterile medical devices (Pharma®, Computer Engineering). The sex ratio, indication for craniectomy, operating time, time between craniectomy and cranioplasty, complications and aesthetic result were statistically analyzed.

RESULTS

The main indications are stroke (n=59; 78.5%) and aneurysms (n=7; 9.5%). Among the 75 patients, 52 benefited from the placement of a custom implant (PolyEtherEtherCetone/PEEK or Hydroxyapatite) and 23 from cementoplasty. The operating time was significantly shorter (P<0.05) for custom cranioplasty (1.93±0.61h vs. 1.62±0.53). Only 4 patients (5.3%) were not satisfied with the aesthetic result following the placement of a custom implant. A greater risk of infection was found in the context of cementoplasty (43% for cementoplasties vs. 25% for the custom implant, so χ2 (P=0.1095), this difference not being statistically significant.

CONCLUSION

This collaborative work between the pharmacy and the adult neurosurgery department served to establish an initial register for monitoring patients who have undergone cranioplasty for whom the ideal implant remains to be determined.

Safety and efficacy of antibiotic-impregnated absorbable calcium sulfate beads (Stimulan) in cranioplasty

Cranioplasty is a common neurosurgical procedure that follows hemicraniectomy in the setting of neoplasm resection or increased intracranial pressure. Although standardized practices aim at minimizing infection risk, infection of the surgical site has been reported in 6.6%-8.4% of patients. In this work, we document the novel use of synthetic dissolvable antibiotic-impregnated calcium sulfate beads (STIMULANⓇ Rapid Cure, Biocomposites Ltd, Wilmington, NC, USA) in five cases of cranioplasty at our institution. Four patients experienced wound healing as expected with no complications related to the use of Stimulan beads. One patient's clinical course was complicated by pseudomeningocele with superficial wound infection occurring 74 days following cranioplasty. Of note, this patient had suffered an avulsion injury and subgaleal hematoma of the scalp ipsilateral to the cranial incision, predisposing to infection due to incompetent scalp vasculature. No complications could be directly attributed to the use of STIMULANⓇ beads.

An update on a persisting challenge: A systematic review and meta-analysis of the risk factors for surgical site infection post craniotomy

BACKGROUND

Surgical site infections (SSIs) postcraniotomy continue to impose a significant burden on health care systems and patient outcomes. It is, therefore, important to understand their risk factors in order to promote effective preventative measures. This meta-analysis aims to provide a comprehensive, up-to-date analysis of the risk factors associated with SSIs in neurosurgical procedures.

METHODS

A systematic review was conducted as per preferred reporting items for systematic reviews and meta-analysis guidelines to explore existing primary evidence on the risk factors for SSIs postcraniotomy. A comprehensive search of MEDLINE, EMBASE, and Pubmed was performed from database inception up to June 2023. 43 studies were included in the meta-analysis, encompassing a total of 68,881 patients.

RESULTS

The strongest predictor for SSIs was found to be cerebrospinal fluid (CSF) leak (OR: 8.91, CI: 4.30-18.44). Other significant factors included infratentorial surgery (OR: 0.43, CI: 0.31-0.61), emergency surgery (OR: 1.41, CI: 1.05-1.91), reintervention (OR: 3.19, CI: 1.77-5.75), prolonged operative time (mean difference: 33.25; CI: 18.83-47.67), hospital length of stay (mean difference: 0.60; CI: 0.23-0.98) and intracranial pressure monitor (ICPM) insertion (OR: 1.81; CI: 1.06-3.11). Contrarily, sex, body mass index (BMI), diabetes, antibiotic prophylaxis, immunosuppressive agents, trauma, use of artificial implants did not demonstrate statistical significance.

CONCLUSIONS

This meta-analysis provides an up-to-date and comprehensive evaluation of risk factors for SSIs postcraniotomy. It emphasizes the need for preventive strategies, particularly against CSF leaks, and calls for further research to elucidate the intricate relationships between these factors.

Cranioplasty in Oman: Retrospective review of cases from the National Craniofacial Center 2012-2022

Objectives

Cranioplasty is a complex craniofacial and neurosurgical procedure that aims to reinstate the architecture of the cranial vault and elevate both its aesthetic and neurological function. Several reconstructive materials have been thoroughly explored in the search for the optimal solution for cranioplasty. This study aimed to evaluate different material used for cranial reconstruction in Oman.

Methods

This retrospective study included all patients who had had cranioplasty procedures performed at Khoula Hospital, Muscat, Oman, from 2012 to 2022. Demographic information, the characteristics of the cranial defect and any complications that occurred post-operatively were analysed.

Results

A total of 47 patients were included in this study. The most common cause of cranial defects was craniectomy following traumatic head injury (70.2%) along with excision of fibrous dysplasia (10.6%). The most frequently utilised material for cranial repair was autologous bone grafts (n = 28), followed by polyetheretherketone (PEEK; n = 14). Interestingly, the replacement of bone grafts from previous craniectomy showed a notably high resorption rate (71.4%), in contrast to split calvarial grafts (0%) and other types of bone grafts (14.3%). Additionally, delayed graft infection was observed in 3.6% of the bone graft group and 7.1% of the PEEK group.

Conclusion

Patient-specific alloplastic implants such as PEEK have gained popularity for large and complex cranioplasty, as they provide excellent aesthetic outcomes and leave no donor site morbidity. In contrast, bone grafts remain the gold standard for small to medium-sized cranial defects.

Lowering Cranioplasty Infection Incidence with Novel Bone Flap Storage Protocol: A Retrospective Cohort Study

BACKGROUND

After craniectomy, autologous bone flaps may be stored using wet or dry cryopreservation. After brain edema subsides, they are replaced during an operation termed cranioplasty. Cranioplasty is associated with 15% infection incidence.

METHODS

We conducted a retrospective comparison of infection outcomes between wet and dry cryopreservation of cranioplasty bone flaps. Historically, bone flaps were stored utilizing wet cryopreservation-bone flap storage in 1 L of lactated Ringer's solution containing 80 mg gentamicin and 2 g nafcillin in a sterile plastic container secured in an unsterile plastic bag. Our newer dry cryopreservation protocol involved storage in gauze soaked in 80 mg gentamicin and 2 g nafcillin within a 3-layer sterile bag system.

RESULTS

A total of 119 autologous bone flaps were included, with median follow-up of 3.9 months from cranioplasty. Overall, 10.9% became infected, requiring subsequent surgery; 18.4% of 49 bone flaps stored using wet cryopreservation became infected compared with only 5.7% of 70 dry cryopreservation bone flaps (P = 0.038; relative risk [RR] 0.311; absolute risk reduction 12.7%). Tobacco use (P = 0.076; RR 3.17) was not associated with increased infection risk. Infection incidence was similar for traumatic craniectomy indications compared to the other indications (12.0% trauma vs. 10.1% other; P = 0.750). On average, infected cranioplasty patients spent 8.5 more days hospitalized and faced increased risk of additional complications.

CONCLUSIONS

Dry cryopreservation significantly decreases infection after cranioplasty when compared with wet cryopreservation, and this mitigates additional morbidity, mortality, and costs attributable to cranioplasty infection. Other nonmodifiable risk factors for cranioplasty infection were identified.

Surgical treatment of feline intracranial meningiomas: a retrospective study of 26 cases

BACKGROUND

Surgical excision is the treatment of choice for feline intracranial meningioma.

OBJECTIVES

To report clinical findings, complications, and outcomes following surgery for feline intracranial meningioma.

METHODS

Medical records (01/2000-01/2017) of cats that underwent surgical excision of an intracranial meningioma at our institution were reviewed. Patient data included signalment, clinical signs, surgical technique, complications, histopathologic diagnosis, survival time, and owners' answers to a satisfaction questionnaire. Survival was assessed using the Kaplan-Meier method and log-rank test.

RESULTS

Twenty-six cats were included in this study. The exact cause of death was known in 17 cases and was not related to meningioma in 9/17 cases. Overall median survival time was 881 days (95% confidence interval 518; 1248). The age of the cat did not influence survival (p = 0.94) or the occurrence of complications (p = 0.051). Complications occurred in 13/24 cats, including dramatic complications in 4/24 cats. Most complications appeared in the first 24 hours post-surgery (12/13). Males had more postoperative complications (p = 0.042), including more seizures (p = 0.016). Cats with cranioplasty had fewer complications (p = 0.021). Clinical recurrence was confirmed in 3 out of 17 cats. Recurrence-free survival time was 826 days. Most owners (12/14) were satisfied with the outcome.

CONCLUSIONS

Surgical treatment of intracranial meningioma in cats was associated with a long median survival time but also with a high rate of minor and major postoperative complications, including early postoperative seizures. Cranioplasty may reduce complications. Age at the time of surgery had no effect on outcomes.

Intrawound Vancomycin Powder Application for Preventing Surgical Site Infection Following Cranioplasty

OBJECTIVE

Surgical site infection is the most detrimental complication following cranioplasty. In other surgical fields, intrawound vancomycin powder application has been introduced to prevent surgical site infection and is widely used based on results in multiple studies. This study evaluated the effect of intrawound vancomycin powder in cranioplasty compared with the conventional method without topical antibiotics.

METHODS

This retrospective study included 580 patients with skull defects who underwent cranioplasty between August 1, 1998 and December 31, 2021. The conventional method was used in 475 (81.9%; conventional group) and vancomycin powder (1 g) was applied on the dura mater and bone flap in 105 patients (18.1%; vancomycin powder group). Surgical site infection was defined as infection of the incision, organ, or space that occurred after cranioplasty. Surgical site infection within 1-year surveillance period was compared between the conventional and vancomycin powder groups with logistic regression analysis. Penalized likelihood estimation method was used in logistic regression to deal with zero events. All local and systemic adverse events associated with topical vancomycin application were also evaluated.

RESULTS

Surgical site infection occurred in 31 patients (5.3%) and all were observed in the conventional group. The median time between cranioplasty and detection of surgical site infection was 13 days (range, 4-333). Staphylococci were the most common organisms and identified in 25 (80.6%) of 31 cases with surgical site infections. The surgical site infection rate in the vancomycin powder group (0/105, 0.0%) was significantly lower than that in the conventional group (31/475, 6.5%; crude odds ratio [OR], 0.067; 95% confidence interval [CI], 0.006-0.762; adjusted OR, 0.068; 95% CI, 0.006-0.731; p=0.026). No adverse events associated with intrawound vancomycin powder were observed during the follow-up.

CONCLUSION

Intrawound vancomycin powder effectively prevented surgical site infections following cranioplasty without local or systemic adverse events. Our results suggest that intrawound vancomycin powder is an effective and safe strategy for patients undergoing cranioplasty.

Healing Exposed Calvarial Hardware Using Negative-Pressure Wound Therapy and Vashe Wound Solution: Case Report

OBJECTIVE

The management of cranioplasty infections has historically been explantation followed by delayed reimplantation/reconstruction. This treatment algorithm necessitates surgery, tissue expansion, and prolonged disfigurement. In this report, the authors describe a treatment approach consisting of serial vacuum-assisted closure (VAC) with hypochlorous acid (HOCl) solution (Vashe Wound Solution; URGO Medical) as a salvage strategy.

METHODS

A 35-year-old man who sustained head trauma, neurosurgical complications, and severe syndrome of the trephined (SOT; devastating neurologic decline treated by cranioplasty) underwent titanium cranioplasty with free flap. Three weeks postoperation, he presented with pressure-related wound dehiscence/partial flap necrosis, exposed hardware, and bacterial infection. Given the severity of his precranioplasty SOT, hardware salvage was critical. He was treated with serial VAC with HOCl solution for 11 days followed by VAC for 18 days and definitive split-thickness skin graft placement over resulting granulation tissue. Authors also conducted a literature review of cranial reconstruction infection management.

RESULTS

The patient remained healed 7 months postoperatively without recurrent infection. Importantly, his original hardware was retained, and his SOT remained resolved. Findings from the literature review support the use of conservative modalities to salvage cranial reconstructions without hardware removal.

CONCLUSIONS

This study investigates a new strategy for managing cranioplasty infections. The VAC with HOCl solution regimen was effective in treating the infection and salvaging the cranioplasty, thus obviating the complications associated with explantation, new cranioplasty, and recurrence of SOT. There is limited literature on the management of cranioplasty infections using conservative treatments. A larger study to better determine the efficacy of VAC with HOCl solution is underway.

Ultra-High-Molecular-Weight Polyethylene Merlon Shape: Novel Fixation of Artificial Bone for Cranioplasty

BACKGROUND

Cranioplasty is a surgical procedure widely performed for repairing cranial defects caused by external decompression surgery for cerebrovascular disease or traumatic brain injury. We devised a new cranioplasty method using artificial bone made up of ultra-high molecular-weight polyethylene, with serrated wings on the edge. We named this newly designed artificial bone as Merlon shape.

OBJECTIVE

To describe our initial experience with the Merlon shape and evaluate its usefulness and safety in cranioplasty.

METHODS

The serrated wings of the Merlon shape were preoperatively designed for solid fixation and improving cosmetic results by reducing the thickness of the artificial bone. We evaluated 25 patients who underwent cranioplasty with the Merlon shape between December 2018 and December 2021. The causes of bone defects in these patients (male: 9, female: 16; median age: 62 years) were subarachnoid hemorrhage (n = 14), cerebral infarction (n = 8), and traumatic brain injury (n = 3).

RESULTS

There were no postoperative adverse events such as infection, bone resorption, implant exposure, or graft sinking in 24 patients during an average follow-up period of 19 months. One patient experienced acute epidural hemorrhage and required reoperation.

CONCLUSION

This is the first report on the use of the ultra-high molecular-weight polyethylene Merlon shape. Our initial 4-year case series showed good outcomes with this method.

Superficial temporal artery injury and delayed post-cranioplasty infection

OBJECTIVE

Complications after cranioplasty after decompressive craniectomy (DC) have been reported to be as high as 40%. The superficial temporal artery (STA) is at substantial risk for injury in standard reverse question-mark incisions that are typically used for unilateral DC. The authors hypothesize that STA injury during craniectomy predisposes patients to post-cranioplasty surgical site infection (SSI) and/or wound complication.

METHODS

A retrospective study of all patients at a single institution who underwent cranioplasty after decompressive craniectomy and who underwent imaging of the head (computed tomography angiogram, magnetic resonance imaging with intravenous contrast, or diagnostic cerebral angiography) for any indication between the two procedures was undertaken. The degree of STA injury was classified and univariate statistics were used to compare groups.

RESULTS

Fifty-four patients met inclusion criteria. Thirty-three patients (61%) had evidence of complete or partial STA injury on pre-cranioplasty imaging. Nine patients (16.7%) developed either an SSI or wound complication after cranioplasty and, among these, four (7.4%) experienced delayed (>2 weeks from cranioplasty) complications. Seven of 9 patients required surgical debridement and cranioplasty explant. There was a stepwise but non-significant increase in post-cranioplasty SSI (STA present: 10%, STA partial injury: 17%, STA complete injury: 24%, P=0.53) and delayed post-cranioplasty SSI (STA present: 0%, STA partial injury: 8%, STA complete injury: 14%, P=0.26).

CONCLUSIONS

There is a notable but statistically non-significant trend toward increased rates of SSI in patients with complete or partial STA injury during craniectomy.

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.

Cryopreservation of autologous bone flaps following decompressive craniectomy: A new method reduced positive cultures without increase in post-cranioplasty infection rate

Introduction

Cranioplasty (CP) after decompressive craniectomy (DC) is a common neurosurgical procedure. Implementation of European Union (EU) directives recommending bacterial cultures before cryopreservation, lead to increased number of autologous bone flaps being discarded due to positive cultures. A new method for handling bone flaps prior to cryopreservation, including the use of pulsed lavage, was developed.

Research question

The aim was to evaluate the effect of a new method on proportion of positive bacterial cultures and surgical site infection (SSI) following CP surgery.

Material and methods

Sixty-one bone flaps from 53 consecutive DC surgery patients were retrospectively included and the study period was divided into before and after method implementation. Patient demographics, laboratory and culture results, type of CP and occurrence of SSI were analyzed.

Results

Twenty-six and 18 bone flaps were available for analysis during the first and second period, respectively. The proportion of positive bacterial cultures was higher in the first period compared to the second (n ​= ​9(35%) vs 0(0%); p ​= ​0.001), and thus the use of custom made implants was considerably higher in the first study period (p ​= ​0.001). There was no difference in the frequency of post-cranioplasty SSI between the first and second study period (n ​= ​3 (11.5%) vs 1 (4.8%), p ​= ​0.408).

Discussion and conclusion

The new method for handling bone flaps resulted in a lower frequency of positive bacterial cultures, without increased frequency of post-cranioplasty SSI, thus demonstrating it is safe to use, allows compliance with the EU-directives, and may reduce unnecessary discarding of bone flaps.

•

New method of bone flap handling and preservation reduced positive bacterial cultures from 35% to 0%.

•

The new method used pulsed lavage of bone flap with saline solution and subsequent swab culture.

•

There was no increase in post-cranioplasty surgical site infection following introduction of the new method.

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.

The Materials Utilized in Cranial Reconstruction: Past, Current, and Future

BACKGROUND

Cranioplasty (CP) is associated with high complication rates compared to other common neurosurgical procedures. Several graft materials are used for CP, which may contribute to the high complication rates, but data in the literature regarding the influence of graft material on post-CP outcomes are inconsistent making it difficult to determine if, when, and to what extent the graft material impacts the rate of perioperative complications. There is an increased demand to identify and develop superior graft materials.

OBJECTIVE

To review and compare the indications, risks, complications, and patient results associated with the use of different graft materials for cranial reconstructions.

DESIGN

A search through EBSCOhost was conducted using the keywords "craniectomy" or "decompressive craniectomy," "cranioplasty," and "materials." The search was limited to literature published in the English language from 2005 until the present. Ultimately, 69 articles were included in this review. Due to the heterogeneity of the study populations, results, statistical analyses, and collecting methods, no statistical analyses could be performed.

CONCLUSIONS

Several graft materials have been adapted for use in cranial reconstructions with inconsistent results making it unclear if or when one material may be indicated over others. Advances in computer-aided design have led to improved patient-specific implants, but the ideal graft material is still being sought after in ongoing research efforts. Reviewing materials currently available, as well as those in clinical trials, is important to identify the limitations associated with different implants and to guide future research.

Surgical Site Infection After Autologous Cranioplasty for Decompressive Craniectomy in Traumatic Brain Injury: A Retrospective Review of Two Level 1 Trauma Centers

OBJECT

Surgical site infection (SSI) after cranioplasty can result in unnecessary morbidity. This analysis was designed to determine the risk factors of SSI after cranioplasty in patients who received a decompressive craniectomy with the autologous bone for traumatic brain injury (TBI).

METHODS

A retrospective review was performed at two level 1 academic trauma centers for adult patients who underwent autologous cranioplasty after prior decompressive craniectomy for TBI. Demographic and procedural variables were collected and analyzed for associations with an increased incidence of surgical site infection with two-sample independent t tests and Mann Whitney U tests, and with a Bonferroni correction applied in cases of multiple comparisons. Statistical significance was reported with a P value of < 0.05.

RESULTS

A total of 71 patients were identified. The mean interval from craniectomy to cranioplasty was 99 days (7-283), and 3 patients developed SSIs after cranioplasty (4.2%). Postoperative drain placement (P > 0.08) and administration of intrawound vancomycin powder (P = 0.99) were not predictive of infection risk. However, a trend was observed suggesting that administration of prophylactic preoperative IV vancomycin is associated with a reduced infection rate.

CONCLUSIONS

The SSI rate after autologous cranioplasty in TBI patients is lower than previously reported for heterogeneous groups and indications, and the infection risk is comparable to other elective neurosurgical procedures. As such, the authors recommend attempting to preserve native skull and perform autologous cranioplasty in this population whenever possible.

Ultra-high-molecular-weight Polyethylene (UHMWPE) Wing Method for Strong Cranioplasty

We developed a new cranioplasty method that utilizes artificial bone made of ultra-high-molecular-weight polyethylene, with a wedge-shaped edge (UHMWPE Wing). This study shows the methods and data of case series and finite element analyses with the UHMWPE Wing. A circumferential wing was preoperatively designed for a custom-made artificial bone made of UHMWPE to achieve high fixed power and to minimize the usage of cranial implants. Here, we present 4 years of follow-up data and finite element analyses for patients treated with the UHMWPE Wing between February 2015 and February 2019. Eighteen consecutive patients underwent cranioplasty using our UHMWPE Wing design. There were no postoperative adverse events in 17 of the patients for at least 18 months. One case of hydrocephalus experienced screw loosening and graft uplift due to shunt malfunction. Placement of a ventriculo-peritoneal shunt immediately returned the artificial bone to normal position. Finite element analyses revealed that a model using the UHMWPE Wing had the highest withstand load and lowest deformation. This is the first report on the UHMWPE Wing method. This method may enable clinicians to minimize dead space and achieve high strength in cranioplasty.

Complications of cranioplasty in relationship to traumatic brain injury: a systematic review and meta-analysis

Despite being a common procedure, cranioplasty (CP) is associated with a variety of serious, at times lethal, complications. This study explored the relationship between the initial injury leading to decompressive craniectomy (DC) and the rates and types of complications after subsequent CP. It specifically compared between traumatic brain injury (TBI) patients and patients undergoing CP after DC for other indications.A comprehensive search of PubMed, Scopus, and the Cochrane Library databases using PRISMA guidelines was performed to include case-control studies, cohorts, and clinical trials reporting complication data for CP after DC. Information about the patients' characteristics and the rates of overall and specific complications in TBI and non-TBI patients was extracted, summarized, and analyzed.A total of 59 studies, including the authors' institutional experience, encompassing 9264 patients (4671 TBI vs. 4593 non-TBI) met the inclusion criteria; this total also included 149 cases from our institutional series. The results of the analysis of the published series are shown both with and without our series 23 studies reported overall complications, 40 reported infections, 10 reported new-onset seizures, 13 reported bone flap resorption (BFR), 5 reported post-CP hydrocephalus, 10 reported intracranial hemorrhage (ICH), and 8 reported extra-axial fluid collections (EFC). TBI was associated with increased odds of BFR (odds ratio [OR] 1.76, p < 0.01) and infection (OR 1.38, p = 0.02). No difference was detected in the odds of overall complications, seizures, hydrocephalus, ICH, or EFC.Awareness of increased risks of BFR and infection after CP in TBI patients promotes the implementation of new strategies to prevent these complications especially in this category of patients.

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.

Clinical Efficacy and Safety of Silicone Elastomer Sheet during Decompressive Craniectomy: Anti-Adhesive Role in Cranioplasty

(1) Background: Cranioplasty is a surgery to repair a skull bone defect after decompressive craniectomy (DC). If the process of dissection of the epidural adhesion tissue is not performed properly, it can cause many complications. We reviewed the effect of a silicone elastomer sheet designed to prevent adhesion. (2) Methods: We retrospectively reviewed 81 consecutive patients who underwent DC and subsequent cranioplasty at our institution between January 2015 and December 2019. We then divided the patients into two groups, one not using the silicone elastomer sheet (n = 50) and the other using the silicone elastomer sheet (n = 31), and compared the surgical outcomes. (3) Results: We found that the use of the sheet shortened the operation time by 24% and reduced the estimated blood loss (EBL) by 43% compared to the control group. Moreover, the complication rate of epidural fluid collection (EFC) in the group using the sheet was 16.7%, which was lower than that in the control group (41.7%, p < 0.023). Multivariate logistic regression analysis showed the sheet (OR 0.294, 95% CI 0.093–0.934, p = 0.039) to be significantly related to EFC. (4) Conclusions: The technique using the silicone elastomer sheet allows surgeons to easily dissect the surgical plane during cranioplasty, which shortens the operation time, reduces EBL, and minimizes complications of EFC.

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

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

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.

Japanese National Questionnaire Survey in 2018 on Complications Related to Cranial Implants in Neurosurgery

Cranial implants are commonly used throughout the world, yet the data on complications remain partly clarified. The aim of this study was to gather real data in 2018 on complications related to cranial implants in neurosurgery. The survey population consisted of 1103 institutes supplying neurosurgical treatment. The survey consisted of two-stage questionnaire. First the incidence of complications was investigated, then the secondary questionnaire was e-mailed to the respondents about the detailed of the complications. As the result, the annual incidence of complications related to cranial implants was 0.558% in Japan. Titanium plate and mesh were used predominantly in craniotomy and cranioplasty, respectively. The second survey collected data on 449 cases with complications (infection: 63%, implant exposure: 46%, multiple answer). Postoperative infection was associated with male sex, brain tumor, short interval between surgery and complication, usage of ceramics, hydroxyapatite, resin, and artificial dura, hyponutrition, multiple surgeries, dirty wound, and sinusitis as patient factors, and CSF leakage, ruptured sutures, and sinus maltreatment as surgery factors. Meanwhile, long hospital stay was associated with age, male sex, mRS 3–5 before complication, short interval between initial surgery and complication, large craniotomy, long operative time, usage of ceramics and artificial dura, multiple surgeries and dirty wound as patient factors, ruptured suture as a surgical factor, and bacterial infection, especially MRSA infection, as the complication and treatment consisting of removal as complication factors. In conclusion, this is the first Japanese national survey on complications related to cranial implants in neurosurgery. It is important to recall that complications may arise years after surgery and to be aware of the risk factors associated with complications.

Use of Focused Ultrasound (Sonication) for the Diagnosis of Infections in Neurosurgical Operations: A Systematic Review and Meta-Analysis

OBJECTIVE

Postoperative infections are one of the most devastating complications in neurosurgery, and their results are even more disastrous when biocompatible implants are involved. As the application of these implants increases, the need for a sensitive and efficient method to detect pathogens becomes imperative. The application of sonication appears to be a viable option.

METHODS

A systematic review and meta-analysis of the available literature was conducted, looking for studies reporting findings from the application of sonication following neurosurgical operations. To be included, an article needed to contain information about the material that was subjected to sonication, indication of other culture methods that were applied, and information about the isolated pathogens.

RESULTS

Six studies comprising 437 patients were included in the meta-analysis. Potential superiority of sonication over conventional microbiologic methods was found in the detection of gram-positive bacteria and in particular of coagulase-negative Staphylococcus species. A sensitivity of 0.87 and a specificity of 0.57 were calculated.

CONCLUSIONS

Regardless of the potential of sonication, it is still not a panacea. Additional studies are expected to provide significant insight into the indications and limitations of this technique.

Dose-response association of operative time and surgical site infection in neurosurgery patients: A systematic review and meta-analysis

BACKGROUND

The association of operative time and surgical site infection (SSI) in neurosurgery patients is unclear. We therefore, through a systematic review and meta-analysis, sought to clarify the association.

METHODS

We performed a systematic search of the PubMed and Embase databases, from January 1, 1966, to December 26, 2018, for published articles. We used random effects generalized least squares regression models to combine study-specific relative risks (RR) and 95% confidence intervals (CI), and performed a sensitivity analysis by excluding 1 study at a time to assess the stability of results and potential sources of heterogeneity. We used the Egger (from plotting to test) to assess publication bias.

RESULTS

A total of 5 articles, with 231,915 individuals and 6,726 SSI cases, were included. The summary RR for SSI after craniotomy were 1.67 (95% CI, 1.13-2.20), with high versus low operative time, and 1.34 (95% CI, 1.15-1.53), with each 1-hour increase in operative time. On sensitivity analysis, no individual study had an excessive influence on the pooled effect. We found no evidence of publication bias by the Egger test (P = .464) and Egger's plotting.

CONCLUSIONS

Prolonged operative time can increase the SSI risk for neurosurgery patients. Intensive interventions should be taken to decrease operative duration.

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.

[Modern aspects of reconstructive surgery of skull defects]

The aim of this study is to systematize the modern methods used for reconstruction of extensive and complex skull defects. Special attention is paid to computer technologies, including 3D imaging and CAD/CAM. Laser-based stereolithography is thoroughly reviewed among other additive technologies. We present our view of the problem associated with proper timing of cranioplasty and choice of materials for it. Complications of skull defect reconstruction are also discussed.

Autologous Bone Cranioplasty: A Retrospective Comparative Analysis of Frozen and Subcutaneous Bone Flap Storage Methods

OBJECTIVE

The use of autologous bone for cranioplasty offers superior cosmesis and cost-effectiveness compared with synthetic materials. The choice between 2 common autograft storage mechanisms (subcutaneous vs. frozen) remains controversial and dictated by surgeon preference. We compared surgical outcomes after autologous bone cranioplasty between patients with cryopreserved and subcutaneously stored autografts.

METHODS

Ten-year retrospective comparative analysis of patients undergoing cranioplasty with autologous bone stored subcutaneously or frozen at a tertiary academic medical center.

RESULTS

Ninety-four patients were studied, with 34 (36.2%) bone flaps stored subcutaneously and 59 (62.8%) frozen. The 2 groups were similar in demographics, comorbidities, and craniectomy indication, with only body mass index and race differing statistically. The mean operation time was greater within the subcutaneous group (P < 0.001), which also had a greater number of ventriculoperitoneal shunt (VPS) placements (P = 0.02). There were no significant differences in complications, readmissions, unplanned reoperations, or length of stay between the 2 groups. VPS placement during cranioplasty increased length of stay (P < 0.001), and placement prior to cranioplasty increased both length of stay (P = 0.009) and incidence of hospital-acquired infection (P = 0.03).

CONCLUSIONS

Subcutaneous and frozen storage of autologous bone result in similar surgical risk profiles. Cryopreservation may be preferred because of shorter operation time and avoidance of complications with the abdominal pocket, whereas the portability of subcutaneous storage remains favorable for patients undergoing cranioplasty at a different institution. VPS placement prior to cranioplasty should be avoided, if possible, due to the increased risk of hospital-acquired infection.

Risk factors for surgical site infections in neurosurgery

INTRODUCTION

Surgical site infections (SSIs) are of profound significance in neurosurgical departments, resulting in high morbidity and mortality. There are limited public data regarding the incidence of SSIs in neurosurgery. The aim of this study was to determine the rate of SSIs (particularly those requiring reoperation) over a seven-year period and identify factors leading to an increased risk.

METHODS

An age matched retrospective analysis was undertaken of a series of 16,513 patients at a single centre. All patients who required reoperation for suspected SSIs within a 7-year period were identified. Exclusion criteria comprised absence of infective material intraoperatively and patients presenting with primary infections. Clinical notes were reviewed to confirm presence or absence of suspected risk factors.

RESULTS

Of the 16,513 patients in the study, 1.20% required at least one further operation to treat a SSI. Wound leak (odds ratio [OR]: 27.41), dexamethasone use (OR: 3.55), instrumentation (OR: 2.74) and operative duration >180 minutes (OR: 1.85) were statistically significant risk factors for reoperation.

CONCLUSIONS

This is the first UK study of such a duration that has documented a SSI reoperation rate in a cohort of this size. Various risk factors are associated with the development of SSIs, making it essential to have robust auditing and monitoring of high risk patients to ensure excellent standards of healthcare. Departmental and public registers to record all SSIs may be beneficial, particularly for those treated solely by general practitioners, allowing units to address potential risk factors prior to surgical intervention.

Conservative Treatment for Delayed Infection After Cranioplasty With Titanium Alloy

Cranioplasty (CP) is considered a low-risk operation in the field of neurosurgery following decompression craniectomy. Nevertheless, CP is still burdened by surgical complications, among which early or late infections are the most common outcome-threatening ones. Most of infection cases occur within a week after CP. Except that, implant-associated scalp infection is the most common complication, and leads to implant removal in many patients with refractory and recurrent infection. The authors reported a patient presenting with epidural infection about 3 months after titanium implant and cured by anti-infective treatment for 2 weeks.

Cranioplasty following decompressive craniectomy: minor surgical complexity but still high periprocedural complication rates

Cranioplasty following decompressive craniectomy is of low surgical complexity, so much so that it has become the "beginners" cranial case. However, these "simple" procedures may have high complication rates. Identification of specific risk factors would allow targeted intervention to lower the complication rates. The aim of this study was to assess the rate of complications and to evaluate potential risk factors. We conducted a review of all patients who underwent cranioplasty in our center following decompressive craniectomy for stroke or brain trauma between 2009 and 2016. One hundred fifty-two patients were identified. Fifty-three percent were male. Mean age was 48 (range 11-78). Median time from craniectomy until cranioplasty was 102 days (range 14-378). The overall rate of complications, such as postoperative bleeding, seizures, postoperative infection, and hydrocephalus, was 30%. The mortality rate was 1%. None of the following potential risk factors was associated with significantly increased risk of periprocedural complications: gender (p = 0.34), age (p = 0.39), cause of initial surgery (p = 0.08), duration of surgery (p = 0.59), time of surgery (0.24), surgical experience (p = 0.17), and time from craniectomy until cranioplasty (p = 0.27). The 30-day complication rate following cranioplasty is high, but serious permanent deficits from these complications were rare. We found no clear predictor for these 30-day complications, which renders its prevention difficult.

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.