Seven years of cranioplasty in a regional neurosurgical centre

Subgaleal drains may be associated with decreased infection following autologous cranioplasty: a retrospective analysis

BACKGROUND

Autologous bone is often the first choice in cranioplasty following a decompressive craniectomy. However, infection is a common complication, with reported rates up to 25%. While the incidence and management of infection are well documented, the risk factors associated with infection remain less clear. The current study aims to identify predictors of infection risk following autologous cranioplasty.

METHODS

A retrospective analysis was conducted on patients who underwent decompressive craniectomy and cranioplasty using cryopreserved autologous bone flaps between 2010 and 2020. Patient demographics and factors related to both surgeries and infection rates were recorded from patient records. Logistic regressions were conducted to determine which factors were implicated in the development of infection.

RESULTS

In our cohort, 126 patients underwent autologous cranioplasty. A total of 10 patients (7.9%) developed an infection following reconstruction, with half resulting in implant failure. We did not identify any significant risk factors for infection. Regression analysis identified placement of subgaleal drain following cranioplasty as a protective factor against the development of infection (OR: 0.16, p = 0.007). On average, drains remained in for 3 days, with no difference between the length of drains for those with infection vs. those without (p = 0.757).

CONCLUSIONS

The current study demonstrates an infection rate of 7.9% in patients who receive an autologous cranioplasty following decompressive craniectomy, which is consistent with previous data. Half (4%) of patients who experienced an infection ultimately required removal of the implant. While it is common practice for neurosurgeons to use drains to prevent hematomas and fluid collections, we found that subgaleal drain placement following cranioplasty was associated with decreased infection, thus demonstrating another benefit of a commonly used tool.

Identifying Independent Predictors of Short-Term Postoperative Morbidity in Patients Undergoing Cranioplasty

BACKGROUND

The present study intends to identify independent predictors of short-term postoperative complications and health utilization in patients undergoing cranioplasty.

METHODS

Demographic, clinical, and intraoperative characteristics were collected for each patient undergoing cranioplasty in the National Surgery Quality Improvement Program database from 2011 to 2020. The 30-day outcomes analyzed were medical complications, wound complications, return to the operating room, extended hospital stay, and non-home discharge. Bivariate analyses were initially used to identify variables that yielded a P value less than 0.2 which were subsequently analyzed in a multivariate logistic regression to identify independent predictors of the aforementioned outcomes.

RESULTS

In total, 2316 patients undergoing cranioplasty were included in the analysis. Increased operative time and totally dependent functional status significantly increased odds of returning to the operating room. Increased age, operative time, cranioplasty size >5 cm, and various comorbidities were associated with increased odds of non-home discharge. Bleeding disorders were independently associated with increased odds of wound complications. Increased age, operative time, cranioplasty size >5 cm, and several medical history features predisposed to medical complications. Demographic characteristics, including age and race, along with various operative and medical history characteristics were associated with increased odds of extended length of stay.

CONCLUSIONS

Identification of risk factors can help guide preoperative risk management in cranioplasty.

Partial Cranial Reconstruction Using Titanium Mesh after Craniectomy: An Antiadhesive and Protective Barrier with Improved Aesthetic Outcomes

OBJECTIVE

Describe a new, safe, technique that uses titanium mesh to partially cover skull defects immediately after decompressive craniectomy (DC).

METHODS

This study is a retrospective review of 8 patients who underwent DC and placement of a titanium mesh. The mesh partially covered the defect and was placed between the temporalis muscle and the dura graft. The muscle was sutured to the mesh. All patients underwent cranioplasty at a later time. The study recorded and analyzed demographic information, time between surgeries, extra-axial fluid collections, postoperative infections, need for reoperation, cortical hemorrhages, and functional and aesthetic outcomes.

RESULTS

After craniectomy, all patients underwent cranioplasty within an average of 112.5 days (30-240 days). One patient reported temporalis muscle atrophy, which was the only complication observed. During the cranioplasties, no adhesions were found between temporalis muscle, titanium mesh, and underlying dura. None of the patients showed complications in the follow-up computerized tomography scans. All patients had favorable aesthetic and functional results.

CONCLUSIONS

Placing a titanium mesh as an extra step during DC could have antiadhesive and protective properties, facilitating subsequent cranioplasty by preventing adhesions and providing a clear surgical plane between the temporalis muscle and intracranial tissues. This technique also helps preserve the temporalis muscle and enhances functional and aesthetic outcomes postcranioplasty. Therefore, it represents a safe alternative to other synthetic anti-adhesive materials. Further studies are necessary to draw definitive conclusions and elucidate long-term outcomes, however, the results obtained hold great promise for the safety and efficacy of this technique.

Sudden death associated with the use of suction drains - a report of 2 cases following uneventful cranioplasty and literature review. Is the use of suction drains safe?

BACKGROUND AND IMPORTANCE

The use of drains, including suction drains in neurosurgery is individual preference-based, rather than scientific evidence-based. Furthermore, the use of suction drains has been associated with significant risks to patients, including sudden death.

CLINICAL PRESENTATION

We present 2 cases of unfortunate sudden deaths following uneventful cranioplasty procedures, both of which were associated with the use of a suction drain. We also review the literature focusing on the benefits and risks in the use of suction drains, and discuss pathophysiological mechanisms underlying sudden death associated with their use.

CONCLUSION

There is no substantial evidence to support the use of suction drains in neurosurgery. Furthermore, they have been associated with significant complications, including risk to life. Our experience and literature review suggest that the risk of sudden death is disproportionately higher following cranioplasty. We do not recommend the use of suction drains in cranial neurosurgery, and we strongly recommend against their use in cranioplasty procedures.

Can Preoperative Laboratory Values Predict Short-term Postoperative Complications and Health Utilization in Patients Undergoing Cranioplasty?

BACKGROUND

Low hematocrit, low albumin, and high creatinine levels have been associated with postoperative morbidity. The present study intends to analyze the effects of preoperative laboratories on medical complications and postoperative health resource utilization in patients undergoing cranioplasty.

METHODS

Using data from the American College of Surgeons National Surgical Quality Improvement Program, demographic, clinical, and intraoperative characteristics were collected for each patient who had recorded albumin, hematocrit, or creatinine laboratory values within 90 days of the index cranioplasty. Outcomes analyzed were ≥1 medical complication, ≥1 wound complication, unplanned reoperation, 30-day readmission, and extended hospital stay (>30 d). Outcomes significant on bivariate analyses were evaluated using multivariate logistic regression. Significant outcomes on multivariate analyses were analyzed using receiver operating characteristic curves and Mann-Whitney U tests.

RESULTS

The 3 separate cohorts included 1349 patients with albumin, 2201 patients with hematocrit, and 2182 patients with creatinine levels. Upon multivariate analysis, increases in albumin and hematocrit were independently associated with decreased odds of medical complications and extended length of stay. Increases in creatinine were independently associated with increased odds of medical complications. Discriminative cutoff values were identified for albumin and hematocrit.

CONCLUSIONS

Preoperative laboratory values were independent predictors of medical complications and health utilization following cranioplasty in this study. Surgical teams can use these findings to optimize preoperative risk stratification.

Risk Factor Analysis of Cryopreserved Autologous Bone Flap Resorption in Adult Patients Undergoing Cranioplasty with Volumetry Measurement Using Conventional Statistics and Machine-Learning Technique

OBJECTIVE

Decompressive craniectomy (DC) with duroplasty is one of the common surgical treatments for life-threatening increased intracranial pressure (ICP). Once ICP is controlled, cranioplasty (CP) with reinsertion of the cryopreserved autologous bone flap or a synthetic implant is considered for protection and esthetics. Although with the risk of autologous bone flap resorption (BFR), cryopreserved autologous bone flap for CP is one of the important material due to its cost effectiveness. In this article, we performed conventional statistical analysis and the machine learning technique understand the risk factors for BFR.

METHODS

Patients aged >18 years who underwent autologous bone CP between January 2015 and December 2021 were reviewed. Demographic data, medical records, and volumetric measurements of the autologous bone flap volume from 94 patients were collected. BFR was defined with absolute quantitative method (BFR-A) and relative quantitative method (BFR%). Conventional statistical analysis and random forest with hyper-ensemble approach (RF with HEA) was performed. And overlapped partial dependence plots (PDP) were generated.

RESULTS

Conventional statistical analysis showed that only the initial autologous bone flap volume was statistically significant on BFR-A. RF with HEA showed that the initial autologous bone flap volume, interval between DC and CP, and bone quality were the factors with most contribution to BFR-A, while, trauma, bone quality, and initial autologous bone flap volume were the factors with most contribution to BFR%. Overlapped PDPs of the initial autologous bone flap volume on the BRF-A crossed at approximately 60 mL, and a relatively clear separation was found between the non-BFR and BFR groups. Therefore, the initial autologous bone flap of over 60 mL could be a possible risk factor for BFR.

CONCLUSION

From the present study, BFR in patients who underwent CP with autologous bone flap might be inevitable. However, the degree of BFR may differ from one to another. Therefore, considering artificial bone flaps as implants for patients with large DC could be reasonable. Still, the risk factors for BFR are not clearly understood. Therefore, chronological analysis and pathophysiologic studies are needed.

Malignant bihemispheric cerebral edema after cranioplasty - An extension of the Monro-Kellie doctrine and predictive factors

Background

Several changes in normal pressure dynamics on the brain occur with a decompressive craniectomy and subsequent cranioplasty. Dead space volume is an important factor contributing to intracranial volume postcranioplasty. A decrease in this volume due to negative suction drain along with relative negative pressure on the brain with the loss of external atmospheric pressure may lead to fatal cerebral edema.

Case Description

A 52-year-old gentleman with a 210 mL volume and middle cerebral artery territory infarction underwent an emergency craniectomy and 6 months later a titanium mold cranioplasty. Precranioplasty computed tomography (CT) scan evaluation revealed a sunken skin flap with a 9 mm contralateral midline shift. Immediately following an uneventful surgery, the patient had sudden fall in blood pressure to 60/40 mmHg and over a few min had dilated fixed pupils. CT revealed severe diffuse cerebral edema in bilateral hemispheres with microhemorrhages and expansion of the sunken right gliotic brain along with ipsilateral ventricular dilatation. Despite undergoing a contralateral decompressive craniectomy due to the midline shift toward the right, the outcome was fatal.

Conclusion

Careful preoperative risk assessment in cranioplasty and close monitoring postprocedure is crucial, especially in malnourished, poststroke cases, with a sinking skin flap syndrome, and a long interval between decompressive craniectomy and cranioplasty. Elective preventive measures and a low threshold for CT scanning and removal of the bone flap or titanium mold are recommended.

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

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

Titanium Versus Autologous Bone-Based Cranioplasty: A Systematic Review and Meta-Analysis

At present, there is no gold standard when looking at reconstructive evidence for cranioplasty with the use of autologous bone as well as other synthetic materials. Titanium has been considered recently as a good option due to its unique properties such as strength and biocompatibility. Numerous studies have previously compared titanium with autologous bone for cranioplasty yet no meta-analysis has been performed within the literature to provide guidelines for craniofacial surgeons. A systematic review and meta-analysis were performed as per the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A search of electronic information was conducted to identify all comparative studies of autologous bone vs. titanium implants in cranioplasty following a craniectomy. The primary outcomes were measured as re-operation rates and cosmesis, the secondary outcome measures included the incidence of complications, for example, bone resorption and infection. Five studies were selected, enrolling 323 cases. A high reoperation rate (p > 0.007) was seen in autologous cranioplasty using bone due to the significantly high resorption rate reported in this group. Cosmetic outcomes demonstrated no significant difference between the two groups examined. Finally, costs and infection rates (p > 0.18) were found to be comparable. Overall, titanium implants used in cranioplasty offer lower re-operation rates in comparison to autologous bone grafts whilst there was no major increase in adverse outcomes such as postoperative cost or rates.

Cranial meningioma with bone involvement: surgical strategies and clinical considerations

BACKGROUND

Intracranial meningioma with bone involvement and primary intraosseous meningioma is uncommon. There is currently no consensus for optimal management. This study aimed to describe the management strategy and outcomes for a 10-year illustrative cohort, and propose an algorithm to aid clinicians in selecting cranioplasty material in such patients.

METHODS

A single-centre, retrospective cohort study (January 2010-August 2021). All adult patients requiring cranial reconstruction due to meningioma with bone involvement or primary intraosseous meningioma were included. Baseline patient and meningioma characteristics, surgical strategy, and surgical morbidity were examined. Descriptive statistics were performed using SPSS v24.0. Data visualisation was performed using R v4.1.0.

RESULTS

Thirty-three patients were identified (mean age 56 years; SD 15) There were 19 females. Twenty-nine patients had secondary bone involvement (88%). Four had primary intraosseous meningioma (12%). Nineteen had gross total resection (GTR; 58%). Thirty had primary 'on-table' cranioplasty (91%). Cranioplasty materials included pre-fabricated polymethyl methacrylate (pPMMA) (n = 12; 36%), titanium mesh (n = 10; 30%), hand-moulded polymethyl methacrylate cement (hPMMA) (n = 4; 12%), pre-fabricated titanium plate (n = 4; 12%), hydroxyapatite (n = 2; 6%), and a single case combining titanium mesh with hPMMA cement (n = 1; 3%). Five patients required reoperation for a postoperative complication (15%).

CONCLUSION

Meningioma with bone involvement and primary intraosseous meningioma often requires cranial reconstruction, but this may not be evident prior to surgical resection. Our experience demonstrates that a wide variety of materials have been used successfully, but that pre-fabricated materials may be associated with fewer postoperative complications. Further research within this population is warranted to identify the most appropriate operative strategy.

Scalp complications of craniofacial surgery: classification, prevention, and initial approach: an updated review

Background

Scalp complications in craniofacial surgeries can increase morbidity and mortality. Given the inelastic characteristics of the scalp, these surgeries can be challenging, and multiple complications can arise. The literature on craniofacial surgery is extensive. However, few articles address scalp complications, associated factors, and prevention. This study aims to identify and classify scalp complications in craniofacial surgery and describe associated risk factors, general preventive measures, and an initial therapeutic approach.

Methods

We conducted a literature search in PubMed, Scopus, Cochrane Library, and LILACS to review the scalp complications in craniofacial surgery. The studies selected included retrospective case series, narrative reviews, systematic reviews, and cadaveric anatomic studies. We completed the search with book chapters and specific topic reviews.

Results

We screened a total of 124 sources and selected 35 items for inclusion in this review. Based on the updated review, we categorized scalp complications into wound defects, soft tissue contour irregularities, neurovascular defects, and infection. We discuss the main characteristics, risk factors, preventive measures, and initial management of these complications.

Conclusions

For craniofacial surgery, understanding the surgical anatomy, identifying risk factors, adequate surgical planning, and interdisciplinary cooperation between neurosurgeons, plastic surgeons, and the interdisciplinary team are essential to prevent and treat scalp complications.

Level of evidence: Not ratable

Evaluation of the Fitting Accuracy of CAD/CAM-Manufactured Patient-Specific Implants for the Reconstruction of Cranial Defects-A Retrospective Study

Cranioplasties show overall high complication rates of up to 45.3%. Risk factors potentially associated with the occurrence of postoperative complications are frequently discussed in existing research. The present study examines the positioning of 39 patient-specific implants (PSI) made from polyetheretherketone (PEEK) and retrospectively investigates the relationship between the fitting accuracy and incidence of postoperative complications. To analyze the fitting accuracy of the implants pre- and post-operatively, STL files were created and superimposed in a 3D coordinate system, and the deviations were graphically displayed and evaluated along with the postoperative complications. On average, 95.17% (SD = 9.42) of the measurements between planned and surgically achieved implant position were within the defined tolerance range. In cases with lower accordance, an increased occurrence of complications could not be demonstrated. The overall postoperative complication rate was 64.1%. The fitting of the PEEK-PSI was highly satisfactory. There were predominantly minor deviations of the achieved compared to the planned implant positions; however, estimations were within the defined tolerance range. Despite the overall high accuracy of fitting, a considerable complication rate was found. To optimize the surgical outcome, the focus should instead be directed towards the investigation of other risk factors.

Cranioplasty Outcomes From 500 Consecutive Neuroplastic Surgery Patients

BACKGROUND

Cranioplasty is critical to cerebral protection and restoring intracranial physiology, yet this procedure is fraught with a high risk of complications. The field of neuroplastic surgery was created to improve skull and scalp reconstruction outcomes in adult neurosurgical patients, with the hypothesis that a multidisciplinary team approach could help decrease complications.

OBJECTIVE

To determine outcomes from a cohort of cranioplasty surgeries performed by a neuroplastic surgery team using a consistent surgical technique and approach.

METHODS

The authors reviewed 500 consecutive adult neuroplastic surgery cranioplasties that were performed between January 2012 and September 2020. Data were abstracted from a prospectively maintained database. Univariate analysis was performed to determine association between demographic, medical, and surgical factors and odds of revision surgery.

RESULTS

Patients were followed for an average of 24 months. Overall, there was a reoperation rate of 15.2% (n = 76), with the most frequent complications being infection (7.8%, n = 39), epidural hematoma (2.2%, n = 11), and wound dehiscence (1.8%, n = 9). New onset seizures occurred in 6 (1.2%) patients. Several variables were associated with increased odds of revision surgery, including lower body mass ratio, 2 or more cranial surgeries, presence of hydrocephalus shunts, scalp tissue defects, large-sized skull defect, and autologous bone flaps. Importantly, implants with embedded neurotechnology were not associated with increased odds of reoperation.

CONCLUSIONS

These results allow for comparison of multiple factors that impact risk of complications after cranioplasty and lay the foundation for development of a cranioplasty risk stratification scheme. Further research in neuroplastic surgery is warranted to examine how designated centers concentrating on adult neuro-cranial reconstruction and multidisciplinary collaboration may lead to improved cranioplasty outcomes and decreased risks of complications in neurosurgical patients.

A Narrative Review of Cell-Based Approaches for Cranial Bone Regeneration

Current cranial repair techniques combine the use of autologous bone grafts and biomaterials. In addition to their association with harvesting morbidity, autografts are often limited by insufficient quantity of bone stock. Biomaterials lead to better outcomes, but their effectiveness is often compromised by the unpredictable lack of integration and structural failure. Bone tissue engineering offers the promising alternative of generating constructs composed of instructive biomaterials including cells or cell-secreted products, which could enhance the outcome of reconstructive treatments. This review focuses on cell-based approaches with potential to regenerate calvarial bone defects, including human studies and preclinical research. Further, we discuss strategies to deliver extracellular matrix, conditioned media and extracellular vesicles derived from cell cultures. Recent advances in 3D printing and bioprinting techniques that appear to be promising for cranial reconstruction are also discussed. Finally, we review cell-based gene therapy approaches, covering both unregulated and regulated gene switches that can create spatiotemporal patterns of transgenic therapeutic molecules. In summary, this review provides an overview of the current developments in cell-based strategies with potential to enhance the surgical armamentarium for regenerating cranial vault defects.

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%.

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

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

Trends and Outcomes of Cranioplasty Alone Versus Single-Stage Composite Scalp and Calvarial Reconstruction

BACKGROUND

Cranioplasty is a critical intervention to restore the calvarium using autologous or alloplastic materials with single-stage composite scalp and calvarial reconstruction reserved for complex cases. This study aims to identify 30-day outcomes in scalp and calvarial reconstruction using the American College of Surgeons National Surgical Quality Improvement Program database.

METHODS

The authors conducted a retrospective analysis of the 2010 to 2018 American College of Surgeons National Surgical Quality Improvement Program database. Adult patients who underwent cranioplasty were identified using current procedural terminology coding and included by exposure type (autologous, alloplastic, composite, or other). Subjects with missing exposure or outcome data were excluded. Primary outcome was 30-day reoperation, whereas secondary outcomes were 30-day unplanned readmission and transfusion. Univariate analysis was completed to assess differences in demographics, comorbidities, and postoperative complications. Multivariable logistic regression was used to control for confounders.

RESULTS

In total, 1719 patients underwent cranioplasty (mean age 54.7 ± 15.3 years, 43.5% male), including 169(9.8%) autologous, 1303(75.8%) alloplastic, 32(1.9%) composite, and 215(12.5%) other procedures. Cranioplasty procedures were associated with 30-day complication and mortality rate of 16.5% and 2.4%, respectively. Composite cranioplasty was associated with decreased 30-day reoperation (adjusted odds ratios 0.11, 95% confidence interval 0.014-0.94, P = 0.044). There was no statistically significant difference in readmission between cranioplasty groups. Alloplastic cranioplasty was associated with decreased odds of postoperative transfusion (adjusted odds ratios 0.47, 95% confidence interval 0.27-0.84, P = 0.01).

CONCLUSIONS

Cranioplasty is an increasingly common procedure. Alloplastic cranioplasty is associated with decreased 30-day transfusion requirement, whereas single-stage composite reconstruction is a viable option and associated with decreased 30-day reoperation with no difference in readmission.

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.

First Report of a Multicenter Prospective Registry of Cranioplasty in the United Kingdom and Ireland

BACKGROUND

There are many questions that remain unanswered regarding outcomes following cranioplasty including the timing of cranioplasty following craniectomy as well as the material used.

OBJECTIVE

To establish and evaluate 30-d outcomes for all cranial reconstruction procedures in the United Kingdom (UK) and Ireland through a prospective multicenter cohort study.

METHODS

Patients undergoing cranioplasty insertion or revision between June 1, 2019 and November 30, 2019 in 25 neurosurgical units were included. Data collected include demographics, craniectomy date and indication, cranioplasty material and date, and 30-d outcome.

RESULTS

In total, 313 operations were included, consisting of 255 new cranioplasty insertions and 58 revisions. Of the new insertions, the most common indications for craniectomy were traumatic brain injury (n = 110, 43%), cerebral infarct (n = 38, 15%), and aneurysmal subarachnoid hemorrhage (n = 30, 12%). The most common material was titanium (n = 163, 64%). Median time to cranioplasty was 244 d (interquartile range 144-385), with 37 new insertions (15%) within or equal to 90 d. In 30-d follow-up, there were no mortalities. There were 14 readmissions, with 10 patients sustaining a wound infection within 30 d (4%). Of the 58 revisions, the most common reason was due to infection (n = 33, 59%) and skin breakdown (n = 13, 23%). In 41 (71%) cases, the plate was removed during the revision surgery.

CONCLUSION

This study is the largest prospective study of cranioplasty representing the first results from the UK Cranial Reconstruction Registry, a first national registry focused on cranioplasty with the potential to address outstanding research questions for this procedure.

Cost-Effective Cranioplasty Utilizing 3D Printed Molds: A Canadian Single-Center Experience

BACKGROUND

Cranioplasty is a commonly performed neurosurgical procedure used to repair defects of the cranial vault. For large defects, 3D printing allows for the creation of patient-specific synthetic cranioplasties. Although these implants provide excellent cosmetic results for patients, costs are quite high. This makes their routine use challenging in the current Canadian healthcare environment. The purpose of this study is to report our experience with a novel, cost-effective method for cranioplasty using desktop 3D printers to manufacture patient-specific molds to aid in the shaping of polymethyl methacrylate (PMMA) cranioplasty intraoperatively.

METHODS

A retrospective review of patients who underwent cranioplasty utilizing 3D printed custom molds was conducted at a single center between 2018 and 2020. Either a two-piece self-align or open-air mold was utilized. Material cost, as well as demographic, clinical, and radiologic data, was reviewed. A five-point ordinance scale was used to evaluate patient satisfaction with cosmesis.

RESULTS

Four patients had previous craniectomies with infected bone flaps, 2 patients had significant bony destruction from tumor invasion, and 1 patient had bone flap resorption. Three patients underwent an open-air mold technique with a Ti-mesh/PMMA-combined implant. The remaining 4 patients underwent two-piece mold with PMMA-only implant. All patients had 'Good' to 'Excellent' cosmetic outcome with one post-operative acute subdural hematoma and one post-operative infection. Two-piece mold resulted in improved cosmetic outcome and cost savings.

CONCLUSIONS

3D printing can be used in a cost-effective manner to deliver good cranioplasty cosmesis. Wider adoption of this technique can result in significant healthcare cost savings without compromising patient outcome.

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.

An improved process for the fabrication and surface treatment of custom-made titanium cranioplasty implants informed by surface analysis

Cranioplasty implants are routinely fabricated from commercially pure titanium plates by maxillofacial prosthetists. The differing fabrication protocols adopted by prosthetists working at different hospital sites gives rise to considerable variations in surface topography and composition of cranioplasty implants, with residues from the fabrication processes having been found to become incorporated into the surface of the implant. There is a growing recognition among maxillofacial prosthetists of the need to standardise these protocols to ensure quality and consistency of practice within the profession. In an effort to identify and eliminate the source of the inclusions associated with one such fabrication protocol, the present study examined the surfaces of samples subjected to each of the manufacturing steps involved. Surface and elemental analysis techniques identified the main constituent of the surface inclusions to be silicon from the glass beads used to texture the surface of the implant during fabrication. Subsequent analysis of samples prepared according to a revised protocol resulted in a more homogeneous titanium dioxide surface as evidenced by the reduction in area occupied by surface inclusions (from 8.51% ± 2.60% to 0.93% ± 0.62%). These findings may inform the development of improved protocols for the fabrication of titanium cranioplasty plates.

Determinants of 30-day Morbidity in Adult Cranioplasty: An ACS-NSQIP Analysis of 697 Cases

Supplemental Digital Content is available in the text.

Cranioplasty is performed to restore the function and anatomy of the skull. Many techniques are used, including replacement of the bone flap and reconstruction with autologous or synthetic materials. This study describes the complication profile of adult cranioplasty using a prospective national sample and identifies risk factors for 30-day morbidity.

Sonolucent Cranial Implants: Cadaveric Study and Clinical Findings Supporting Diagnostic and Therapeutic Transcranioplasty Ultrasound

BACKGROUND

Previously, sonographic evaluation of the intracranial contents was limited to intraoperative use following bone flap removal, with placement of the probe directly on the cortical surface or through a transsulcal tubular retractor. Cranioplasty with sonolucent implants may represent a postoperative window into the brain by allowing ultrasound to serve as a novel bedside imaging modality. The potential sonolucency of various commonly used cranial implant types was examined in this study.

METHODS

A 3-phase study was comprised of cadaveric evaluation of transcranioplasty ultrasound (TCU) with cranioplasty implants of varying materials, intraoperative TCU during right-sided cranioplasty with clear implant made of poly-methyl-methacrylate (PMMA), and bedside TCU on postoperative day 5 after cranioplasty.

RESULTS

The TCU through clear PMMA, polyether-ether-ketone, and opaque PMMA cranial implants revealed implant sonoluceny, in contrast to autologous bone and porous-polyethylene. Intraoperative ultrasound via the clear PMMA implant in a single patient revealed recognizable ventricular anatomy. Furthermore, postoperative bedside ultrasound in the same patient revealed comparable ventricular anatomy and a small epidural fluid collection corresponding to that visualized on an axial computed tomography scan.

CONCLUSION

Sonolucent cranial implants, such as those made of clear PMMA, hold great promise for enhanced diagnostic and therapeutic applications previously limited by cranial bone. Furthermore, as functional cranial implants are manufactured with implantable devices housed within clear PMMA, the possibility of utilizing ultrasound for real-time surveillance of intracranial pathology becomes much more feasible.

Transcranioplasty Ultrasound Through a Sonolucent Cranial Implant Made of Polymethyl Methacrylate: Phantom Study Comparing Ultrasound, Computed Tomography, and Magnetic Resonance Imaging

BACKGROUND

Current methods of transcranial diagnostic ultrasound imaging are limited by the skull's acoustic properties. Craniotomy, craniectomy, and cranioplasty procedures present opportunities to circumvent these limitations by substituting autologous bone with synthetic cranial implants composed of sonolucent biomaterials.

OBJECTIVE

This study examined the potential to image the brain using transcranioplasty ultrasound (TCU) through a sonolucent cranial implant.

MATERIALS AND METHODS

A validated adult brain phantom was imaged using computed tomography (CT), magnetic resonance imaging (MRI), and ultrasound without an implant. Next, for experimental comparison, TCU was performed through a sonolucent implant composed of clear polymethyl methacrylate.

RESULTS

All imaging modalities successfully revealed elements of the brain phantom, including the bilateral ventricular system, the falx cerebri, and a deep hyperdense mass representing a brain tumor or hematoma. In addition, ultrasound images were captured which closely resembled axial images obtained with both CT and MRI.

CONCLUSION

The results obtained in this first-ever, preclinical, phantom study suggest TCU is now a viable immediate and long-term diagnostic imaging modality deserving of further clinical investigation.

Risk factors for the development of seizures after cranioplasty in patients that sustained traumatic brain injury: A systematic review

Decompressive craniectomy (DC) is used for the treatment of raised intracranial pressure secondary to traumatic brain injury. Cranioplasty is a reconstructive procedure that restores the structural integrity of the skull following (DC). Seizures are a recognised complication of cranioplasty but its incidence and risk factors in TBI patients are unclear. Accurate prognostication can help direct prophylactic and treatment strategies for seizures. In this systematic review, we aim to evaluate current literature on these factors. A PROSPERO-registered systematic review was performed in accordance with PRISMA guidelines. Data was synthesised qualitatively and quantitatively in meta-analysis where appropriate. A total of 8 relevant studies were identified, reporting 919 cranioplasty patients. Random-effects meta-analysis reveals a pooled incidence of post-cranioplasty seizures (PCS) of 5.1% (95% CI 2.6-8.2%). Identified risk factors from a single study included increasing age (OR 6.1, p = 0.006), contusion at cranioplasty location (OR 4.8, p = 0.015), and use of monopolar diathermy at cranioplasty (OR 3.5, p = 0.04). There is an association between an extended DC-cranioplasty interval and PCS risk although it did not reach statistical significance (p = 0.062). Predictive factors for PCS are poorly investigated in the TBI population to date. Heterogeneity of included studies preclude meta-analysis of risk factors. Further studies are required to define the true incidence of PCS in TBI and its predictors, and trials are needed to inform management of these patients.

Functional and aesthetic evaluation after cranial reconstruction with polymethyl methacrylate prostheses using low-cost 3D printing templates in patients with cranial defects secondary to decompressive craniectomies: A prospective study

Background:

Cranial reconstruction surgery is a procedure used as an attempt to reestablish the cranial bone anatomy. This study evaluates the symptomatic and aesthetic improvement of patients with cranial defects secondary to decompressive craniectomies after cranial reconstruction with customized polymethyl methacrylate (PMMA) prostheses. Secondly, we aim to divide our experience in the production of these prostheses with a low-cost method.

Methods:

A prospective study was carried out with patients submitted to cranioplasty at the Hospital da Restauração between 2014 and 2017. A total of 63 cranioplasties were performed using customized PMMA prosthesis produced by 3D impression molds. All patients underwent a functional and aesthetic evaluation questionnaire in the preoperative period and in the sixth postoperative month.

Results:

Sixty-three patients underwent cranioplasty with a mean age of 33 years, ranging from 13 to 58 years, 55 males and 8 females. The mean area of the defect was 147 cm². The mean postoperative follow-up of the patients was 21 months, ranging from 6 to 33 months. Fifty-five patients attended the 6-month postoperative consultation. All patients presented symptomatic improvement after reconstruction of the skull. The infection rate was 3.2%, 4.8% of extrusion, 1.6% of prosthesis fracture, 7.9% of extradural hematoma, 17.4% of reoperation, 5% of wound dehiscence, and 4.8% of removal of the prosthesis.

Conclusion:

Cranioplasty, with a customized PMMA prosthesis, improved the symptoms and aesthetic appearance of all operated patients. The use of prototypes to customize cranial prostheses facilitated the operative technique and allowed the recovery of a cranial contour very close to normal.

The "Negative" Impact of a Subgaleal Drain: Post-cranioplasty Negative Pressure Subgaleal Drain-induced Ascending Transtentorial Herniation

One commonly practiced procedural step to reduce the risk of postoperative hematoma accumulation when performing cranioplasties is to place a closed negative-pressure subgaleal drain. We present a patient with sinking skin flap syndrome that underwent such a procedure and subsequently experienced immediate postoperative ascending transtentorial herniation and intracranial hemorrhage remote from the surgical site. On determining that the subgaleal drain was the responsible cause, it was immediate removed, and the patient had neurological recovery. Fewer than 30 cases of life-threatening subgaleal drain-related complications have been documented, and this is the first reported case of ascending herniation occurring after cranioplasty. This report illustrates the potential risks of subgaleal drainage, the importance of early recognition of this rare phenomenon and that intervention can be potentially life-saving.

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.

Reduction of Surgical Site Infections After Cranioplasty With Perioperative Bundle

BACKGROUND

Surgical site infections (SSI) are the most common complication after cranioplasty and it is associated with poor prognosis. The aim of this study was to identify the risk factors that triggered the development of SSI after cranioplasty and establish a new perioperative bundle and monitoring system to reduce SSI.

METHODS

A retrospective review of a database that included all cranioplasty patients from 2001 to 2007 was carried out to determine the prevalence of infection. A surveillance team was set up, which assessed the clinical practice and led to the development of a new perioperative bundle and supervision system. A prospective study between 2008 and 2014 was carried out to observe whether infection rates had changed and whether an active surveillance program can change clinical practice.

RESULTS

Retrospective period included 86 adult patients. The overall rate of infection was 10.5% (9 SSI in 86 patients). Age ≥60 years (OR 1.05; 95% CI: 1.00-1.10; P = 0.04), smoking (OR 9.13; 95% CI: 1.65-50.60; P = 0.01), and duration of operation ≥180 minutes (OR1.19; 95% CI: 1.06-1.34; P < 0.01) as significant predictors of postcranioplasty SSI development. Length of preoperative stay and length of hospitalization was significantly longer among infected patients compared with uninfected patients (P < 0.01, respectively). In prospective period, the general SSI rate was reduced to 1.8% (2 SSI in 113 patients). The difference was statistically significant (P = 0.01).

CONCLUSIONS

A perioperative bundle and monitoring system may help to reduce SSI rates after cranioplasty. This work also indicates how an active surveillance program can successfully change clinical practice.

Seizure After Cranioplasty: Incidence and Risk Factors

BACKGROUND

To investigate clinical characteristics of postcranioplasty seizures (PCS) first observed after cranioplasty after decompressive craniectomy (DC) to treat traumatic brain injury and to define factors that increase PCS risk.

METHODS

This retrospective study, covering the period between January 2008 and July 2015, compared PCS in postcranioplasty patients. Postcranioplasty seizures risk factors included diabetes mellitus, hypertension, time between DC and cranioplasty, duraplasty material, cranioplasty contusion location, electrocautery method, PCS type, and infection. Multivariate logistic regression analysis was performed and confidence intervals (CIs) were calculated (95% CI).

RESULTS

Of 270 patients, 32 exhibited initial PCS onset postcranioplasty with 11.9% incidence (32/270). Patients fell into immediate (within 24 hours), early (from 1 to 7 days), and late (after 7 days) PCS groups with frequencies of 12, 5, and 15 patients, respectively. Generalized, partial, and mixed seizure types were observed in 13, 13, and 6 patients, respectively. Multivariate logistic regression analysis showed increased risk with increasing age (>50 years). Cranioplasty contusion location, precranioplasty deficits, duraplasty material, and monopolar electrocautery were predictive of PCS onset (P < 0.05). Increased DC to cranioplasty interval increased risk but was not statistically significant (P = 0.062).

CONCLUSIONS

Understanding risk factors for PCS will benefit the management of cranioplasty patients.

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.

Massive Brain Swelling and Death After Cranioplasty: A Systematic Review

BACKGROUND

Although cranioplasty is a common procedure, it may cause a variety of complications. Massive brain swelling after cranioplasty (MBSC) is an unusual complication that has been reported more frequently in recent years. Most of the existing information about this condition is speculative and the cause remains unclear.

METHODS

A PubMed and Scopus search adhering to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines was performed to include studies reporting patients with MBSC. Different information was analyzed in these cases to describe the characteristics and identify risk factors for MBSC.

RESULTS

The search yielded 19 articles with a total of 26 patients. All studies were case reports and small case series. In most patients, preoperative intracranial hypotension and a considerable degree of sinking of skin flap were identified; this was the only constant finding observed in these cases. In addition, we propose a grading system to estimate the degree of preoperative sinking of skin flap and an algorithm with recommendations to decrease the incidence of MBSC.

CONCLUSIONS

MBSC is an unusual, highly lethal, and probably underreported condition. The information gathered in this review indicates that MBSC occurs secondary to a cascade of pathologic events triggered by the bone flap implantation. This evidence suggests that the primary pathologic change is a sudden increase in the intracranial pressure acting on a brain chronically exposed to intracranial hypotension.

Malignant Cerebral Swelling After Cranioplasty: Case Report and Literature Review

BACKGROUND

Cranioplasty is considered a low-risk operation in the field of neurosurgery following decompression craniectomy. Well-known complications after cranioplasty, such as infection, seizure, and titanium plate exposure, may not threaten the lives of patients. Unfortunately, there are many fatal complications that are underreported. In this study, we report a case and perform a literature review to introduce malignant cerebral swelling, which is regarded as a devastating complication.

CASE DESCRIPTION

A 51-year-old man who was a victim of traumatic brain injury underwent emergency clot removal and decompression craniectomy. His neurologic condition improved with subsequent rehabilitation therapy, and he had left sinking skin flap syndrome where the skull was defective. Six months after the initial surgery, he underwent a cranioplasty; however, he did not recover from the uneventful anesthesia. A vacuum suction drain showed 300 mL of flow outflow had drained when his pupils dilated and fixed. An immediate computed tomography scan showed ipsilateral diffuse cerebral swelling with diffuse cerebral hemorrhage. Despite all approaches that were considered, the cerebral swelling continued to worsen until death.

CONCLUSION

Cranioplasty is a high-risk procedure in some cases. Sinking skin flap syndrome and vacuum suction drain may be the main risks of a postoperative venous congestion and stasis, which may result in diffuse cerebral swelling. Once the computed tomography scan shows malignant cerebral swelling, the patient is expected to have a poor prognosis.

Never say never again: A bone graft infection due to a hornet sting, thirty-nine years after cranioplasty

Background:

Cranioplasty (CP) is a widespread surgical procedure aimed to restore skull integrity and physiological cerebral hemodynamics, to improve neurological functions and to protect the underlying brain after a life-saving decompressive craniectomy (DC). Nevertheless, CP is still burdened by surgical complications, among which early or late graft infections are the most common outcome-threatening ones.

Case Description:

We report the case of 48-year-old man admitted to our neurosurgical unit because of a painful right frontal swelling and 1-week purulent discharge from a cutaneous fistula. He had been undergone frontal CP because of severe traumatic brain injury (TBI) when he was 9-year-old. Since then, his medical history has been being unremarkable without any surgical or infective complication of the graft for 39 years, until he was accidentally stung by a hornet in the frontal region. After the CT scan and laboratory findings had evidenced a probable infection of the graft, the patient was treated by vancomycin and cefepime before he underwent surgical revision of its former CP, with the removal of the graft and the debridement of the surgical field. Subsequent bacteriological tests revealed Staphylococcus aureus as causal agent of that infection.

Conclusion:

This case illustrates an anecdotal example of very late CP infection, due to an unpredictable accident. Due to lack of consensus on risk factors and on conservative or surgical strategy in case of graft infection, we aimed to share our surgical experience.

Malignant Cerebral Swelling After Cranioplasty due to Ipsilateral Intracranial Vasculopathy: Case Report and Literature Review

BACKGROUND

Cranioplasty is a well-established surgical operation that is used worldwide for patients with skull defects following decompressive craniectomy (DC). However, in some cases, potentially fatal complications may occur, such as malignant cerebral swelling after uneventful cranioplasty.

CASE DESCRIPTION

We present a rare case of massive malignant ipsilateral cerebral swelling following uneventful titanium mesh cranioplasty due to rare ipsilateral intracranial vasculopathy confirmed by magnetic resonance angiography (MRA) and magnetic resonance venography (MRV). Fortunately, we performed titanium mesh explantation and extended DC in time, and the patient survived. Malignant cerebral swelling after uneventful cranioplasty is an unpredictable but fatal complication. Most reported cases have had an unfavorable prognosis. To the best of our knowledge, the mechanism was first confirmed by MRA and MRV, which demonstrated that the cerebral swelling was due to unilateral intracranial vasculopathy, including a rare ipsilateral intracranial internal carotid artery occlusion, as well as extremely thin lateral and sigmoid sinuses.

CONCLUSIONS

Our case demonstrates for the first time that ipsilateral intracranial vasculopathy is a risk factor for malignant cerebral swelling after cranioplasty. Patients with traumatic brain injury with suspected intracranial vasculopathy should undergo a comprehensive vascular evaluation before cranioplasty to help prevent malignant cerebral swelling.

Partial titanium mesh explantation cured post-cranioplasty implant-associated scalp infection

Titanium mesh cranioplasty is routinely used worldwide for skull defect patients given its advantages, such as stability and biocompatibility. However, there are very few reports concerning the treatment of implant-associated scalp infection, which is one of the most common complications. The aim of the study is to retrospectively evaluate a novel operation technique for the treatment of titanium mesh-associated scalp infection post-cranioplasty, namely partial titanium mesh explantation (PTME). A retrospective study was conducted in all patients who underwent surgical treatment for implant-associated scalp infection from January 2012 to September 2016 in our hospital. In total, 17 patients were selected for study analysis among 231 patients who underwent cranioplasty. The treatment success rate of PTME was 85.7%. There was no statistically significant difference in demographics and characteristics except for follow-up length of time between the PTME group and TTME (total titanium mesh explantation) group (Non-paired Student's t-test, P=0.037). While, The PTME group exhibited a significantly reduced skull defect area post-operation compared with the TTME group (Non-paired Student's t-test, P=0.002). Moreover, post-PTME skull area also exhibited a significantly reduced skull defect area compared with the pre-cranioplasty area in the same patient (Non-paired Student's t-test, P=0.006). Compared with traditional surgical treatment of implant-associated scalp infection, PTME combined with strict debridement and antibiotic therapy can cure implant-associated scalp infection. Moreover, PTME could preserve sufficient titanium mesh for brain protection and cosmesis.

Scalp reconstruction: A 10-year retrospective study

Scalp reconstruction is a challenging task for the reconstructive surgeon. In consideration of the anatomical and cosmetic characteristics, the defect depth and size, an armamentarium of reconstructive procedures ranging from skin grafts over local flaps to free tissue transfer has been described. In this 10-year retrospective study, 85 operative procedures for scalp reconstruction were performed at our department. The underlying entity, defect size/depth, reconstructive procedure, complications, and mean hospital stay were analyzed. In most cases, scalp reconstruction was necessary after oncologic resection (67%) or radiation therapy (16%). A total of 85 operative procedures were performed for scalp reconstruction including local flaps (n = 50), free tissue transfer (n = 18), and skin grafts (n = 17). Regarding the complication rate, we could detect an overall major complication rate of 16.5% with one free flap loss. Briefly, local flaps are an adequate and safe procedure for limited scalp defects. In the case of extensive scalp defects affecting the calvarium, prior multiple surgical interventions and/or radiation, we prefer free tissue transfer.

Which One Is Better to Reduce the Infection Rate, Early or Late Cranioplasty?

OBJECTIVE

Decompressive craniectomy is an effective therapy to relieve high intracranial pressure after acute brain damage. However, the optimal timing for cranioplasty after decompression is still controversial. Many authors reported that early cranioplasty may contribute to improve the cerebral blood flow and brain metabolism. However, despite all the advantages, there always remains a concern that early cranioplasty may increase the chance of infection. The purpose of this retrospective study is to investigate whether the early cranioplasty increase the infection rate. We also evaluated the risk factors of infection following cranioplasty.

METHODS

We retrospectively examined the results of 131 patients who underwent cranioplasty in our institution between January 2008 and June 2015. We divided them into early (≤90 days) and late (>90 days after craniectomy) groups. We examined the risk factors of infection after cranioplasty. We analyzed the infection rate between two groups.

RESULTS

There were more male patients (62%) than female (38%). The mean age was 49 years. Infection occurred in 17 patients (13%) after cranioplasty. The infection rate of early cranioplasty was lower than that of late cranioplasty (7% vs. 20%; p=0.02). Early cranioplasty, non-metal allograft materials, re-operation before cranioplasty and younger age were the significant factors in the infection rate after cranioplasty (p<0.05). Especially allograft was a significant risk factor of infection (odds ratio, 12.4; 95% confidence interval, 3.24-47.33; p<0.01). Younger age was also a significant risk factor of infection after cranioplasty by multivariable analysis (odds ratio, 0.96; 95% confidence interval, 0.96-0.99; p=0.02).

CONCLUSION

Early cranioplasty did not increase the infection rate in this study. The use of non-metal allograft materials influenced a more important role in infection in cranioplasty. Actually, timing itself was not a significant risk factor in multivariate analysis. So the early cranioplasty may bring better outcomes in cognitive functions or wound without raising the infection rate.

Complications After In Vivo and Ex Vivo Autologous Bone Flap Storage for Cranioplasty: A Comparative Analysis of the Literature

INTRODUCTION

The most common bone flap storage strategies after decompressive hemicraniectomy for malignant intracranial hypertension include freezer cryopreservation (CP) and subcutaneous abdominal implantation (AP). Numerous series have reported on patient outcomes after cranioplasty in terms of infection, cosmesis, and resorption. This meta-analysis compares published outcomes of bone flap CP and subcutaneous storage with respect to efficacy and complication risk in patients undergoing cranioplasty after hemicraniectomy.

METHODS

A systematic review was performed using PubMed-searchable studies that included bone flap storage methods and outcome data for cranioplasties performed between 1975 and 2015.

RESULTS

A total of 48 studies including 5346 patients were identified that met the inclusion criteria. Of these patients, 4096 underwent cranioplasty with an autologous flap. Mean bone flap storage times for CP and AP flaps were 69.9 and 69.7 days. Mean follow-up time for CP and AP flaps was 16.9 and 16.5 months. No statistically significant differences were found when comparing CP with subcutaneous storage of bone flaps with respect to percentage of patients developing infection (7.3% vs. 7.1%), percentage of patients needing revision surgery (15.9% vs. 7.6%), and percentage of patients experiencing resorption (9.7% vs. 7.7%).

CONCLUSIONS

This is the largest and most robust review comparing published outcomes of CP and subcutaneous storage of bone flaps in patients who have undergone decompressive hemicraniectomy. This review found no statistically significant differences in clinical outcomes (infection, resorption, reoperation) when comparing storage methods for bone flap preservation. This study suggests that both strategies may be used safely and successfully.

Fenestration of bone flap during interval autologous cranioplasty

Background:

Symptomatic extra-axial fluid may complicate cranioplasty and require urgent evacuation. Fenestration (F) of the bone flap may encourage extra-axial fluid absorption; however, literature has not explored this technique.

Methods:

Thirty-two consecutive patients who underwent interval autologous cranioplasty were divided into two groups: Fenestration, n = 24, and no fenestration (NF), n = 8. Fenestration involves placement of twist-drill holes 1–2 cm apart throughout the bone flap. Clinical data (age, sex, underlying pathology for cranioplasty, history of antiplatelet/anticoagulation [A/A], presence of drains, and length of Intensive Care Unit [ICU] stay) were collected. Postoperative volume and midline shift (MLS) were measured. Univariate analysis was performed for continuous variables; Fisher's exact test was performed for categorical variables.

Results:

For postoperative volume, NF group exhibited 33.745 ± 48.701 cm³; F group exhibited 20.832 ± 26.103 cm³ (P = 0.351). For MLS, NF group exhibited 3.055 ± 0.472 mm; F group exhibited 0.75 ± 0.677 mm (P = 0.009). MLS for the NF group subset with drains was 1.235 ± 0.566 mm, (P = 0.587 when compared to F group). For ICU length of stay, NF group exhibited 1.958 ± 1.732 days; F group exhibited 2.290 ± 0.835 days (P = 0.720). In NF group, for patients with no A/A, no drain exhibited MLS 4.00 ± 0.677 mm while a drain exhibited 1.845 ± 0.605 mm (P = 0.025); with A/A, no drain exhibited 5.75 ± 1.353 mm while a drain exhibited 0.625 ± 0.957 (P = 0.005). Four NF patients required reoperation compared to zero F patients (P = 0.550).

Conclusion:

Presumably, fenestrations augment surface area for extra-axial fluid absorption through the bone flap. Our results, regarding MLS and postoperative volume, provide support for this concept. Accordingly, bone flap fenestration has the potential to reduce extra-axial fluid accumulation.

Cranioplasty complications and risk factors associated with bone flap resorption

Background

Decompressive craniectomy (DC) may be performed in patients with acutely raised intracranial pressure due to traumatic brain injury or stroke. It is later followed by a cranioplasty procedure (CP) in the surviving patients. This procedure is associated with a high frequency of post-operative complications. Identifying risk factors for these adverse events is important in order to improve the clinical outcome. This study examines possible predictive parameters for post-operative complications in CP.

Methods

Retrospective, single institution review of all patients undergoing a DC for acutely raised intracranial pressure over a 10 year period at Oslo University Hospital Ullevål, Norway. Subsequent CP using autologous bone flaps or synthetic implants were registered along with all post-operative complications. Predictors of post-operative complications were identified using uni –and multivariable regression analyses.

Results

A DC was carried out in 125 patients, of whom 33 died, 4 were lost to follow-up, and 1 (an infant) later underwent cranial remodeling. A CP was performed in the remaining 87 patients. Post-operative complications were recorded in 31 (36 %) patients of whom 22 lost their primary implant. Surgical site infection (SSI) and bone flap resorption (BFR) were the two most common complications, affecting 8 (9.2 %) and 14 (19.7 %) patients, respectively. Only BFR was associated with some of the recorded variables. Using multivariable logistic regression analysis, young age (OR = 0.94, 95 % CI 0.88-1.00, p = 0.04), bone flap fragmentation (OR = 14.3, 95 % CI 2.26-89, p = 0.005), long storage time (OR = 1.03, 95 % CI 1.00-1.04, p = 0.02) and Glasgow Outcome Scale at the time of cranioplasty (OR = 2.55, 95 % CI 1.04-6.23, p = 0.04) were found to be significant risk factors for bone flap resorption.

Conclusions

Cranioplasty after decompressive craniectomy carries a high rate of complications. In this study, SSI and BFR were the two most common complications of which predictive clinical parameters could be identified for BFR only. The results indicate that synthetic implants may be considered in pediatric patients and in cases with fragmented bone flaps or delayed time to cranioplasty. Although the rate of complications was high, 73 % had a successful reinsertion of the autologous graft at a low cost. We feel this result justifies the continued use of cryopreserved bone flaps.