Clinical outcomes in cranioplasty: risk factors and choice of reconstructive material

Optimizing Surgical Outcomes and the Role of Preventive Surgery: A Scoping Review

BACKGROUND

 Plastic and reconstructive surgeons are often presented with reconstructive challenges as a sequela of complications in high-risk surgical patients, ranging from exposure of hardware, lymphedema, and chronic pain after amputation. These complications can result in significant morbidity, recovery time, resource utilization, and cost. Given the prevalence of surgical complications managed by plastic and reconstructive surgeons, developing novel preventative techniques to mitigate surgical risk is paramount.

METHODS

 Herein, we aim to understand efforts supporting the nascent field of Preventive Surgery, including (1) enhanced risk stratification, (2) advancements in postoperative care. Through an emphasis on four surgical cohorts who may benefit from preventive surgery, two of which are at high risk of morbidity from wound-related complications (patients undergoing sternotomy and spine procedures) and two at high risk of other morbidities, including lymphedema and neuropathic pain, we aim to provide a comprehensive and improved understanding of preventive surgery. Additionally, the role of risk analysis for these procedures and the relationship between microsurgery and prophylaxis is emphasized.

RESULTS

 (1) medical optimization and prehabilitation, (2) surgical mitigation techniques.

CONCLUSION

 Reconstructive surgeons are ideally placed to lead efforts in the creation and validation of accurate risk assessment tools and to support algorithmic approaches to surgical risk mitigation. Through a paradigm shift, including universal promotion of the concept of "Preventive Surgery," major improvements in surgical outcomes may be achieved.

Cranioplasty is not required in the reconstruction of small combined scalp and calvarial defects

BACKGROUND

Treatment of scalp malignancies may include the need for craniectomy. The decision to perform cranioplasty is not straightforward and is frequently subjective. The purpose of this study was to assess the clinical outcomes after reconstruction of complex scalp and calvarial defects by comparing patients with and without cranioplasty.

METHODS

Retrospective review of the clinical records of a consecutive series of patients who underwent scalp soft tissue reconstruction after craniectomy for malignancy or osteoradionecrosis between 2014 and 2022 at Royal Melbourne Hospital was conducted. Demographics, previous treatments, surgical details, and post-operative complications were assessed. Traumatic injuries and decompressive craniectomies were excluded. Minimum follow-up of 6 months.

RESULTS

Thirty-seven patients were included in the study. Indications for surgery included skin malignancies, osteoradionecrosis, or both. There was one reconstructive failure (in the non-cranioplasty group). Infection and metalware exposure were common complications in patients who underwent cranioplasty (38.5%). No patient developed neurological symptoms subsequent to craniectomy. One patient needed revision surgery due to esthetic reasons (cranioplasty group). Transposition flaps were associated with more complications and revision procedures.

CONCLUSION

Combined scalp and calvarial defects pose a difficult reconstructive challenge. Stable soft tissue coverage is more reliably achieved with free flap reconstruction. Cranioplasty is not always mandatory and should be reserved for cases with a very large bony defect or when the defect is located in a cosmetically sensitive area.

Perioperative risk factors for major complications after bone replacement in decompressive craniectomy

INTRODUCTION

Bone flap replacement after a decompressive craniectomy is a low complexity procedure, but with complications that can negatively impact the patient's outcome. A better knowledge of the risk factors for these complications could reduce their incidence.

PATIENTS AND METHODS

A retrospective review of a series of 50 patients who underwent bone replacement after decompressive craniectomy at a tertiary center over a 10-year period was performed. Those clinical variables related to complications after replacement were recorded and their risk factors were analyzed.

RESULTS

A total of 18 patients (36%) presented complications after bone flap replacement, of which 10 (55.5%) required a new surgery for their treatment. Most of the replacements (95%) were performed in the first 90 days after the craniectomy, with a tendency to present more complications compared to the subsequent period (37.8% vs 20%, p > 0.05). The most frequent complication was subdural hygroma, which appeared later than infection, the second most frequent complication. The need for ventricular drainage or tracheostomy and the mean time on mechanical ventilation, ICU admission, or waiting until bone replacement were greater in patients who presented post-replacement complications. Previous infections outside the nervous system or the surgical wound was the only risk factor for post-bone flap replacement complications (p = 0.031).

CONCLUSIONS

Postoperative complications were recorded in more than a third of the patients who underwent cranial bone flap replacement, and at least half of them required a new surgery. A specific protocol aimed at controlling previous infections could reduce the risk of complications and help establish the optimal time for cranial bone flap replacement.

Flap Design for Cranial Reconstruction: An Analysis of Craniectomy and Cranioplasty Incisions

Background

The surgical approach for cranial reconstruction is influenced by the presence of pre-existing scar tissue. Scars that lie within the vicinity of cranial defect require modification.

Purpose

The present study was conducted to analyse co-relation between craniectomy scar and cranioplasty incision.

Materials and Methods

A retrospective evaluation of 70 patients who were divided into three groups based on location of cranioplasty incision line was done. In group I, incision was located parallel and outside the scar; group II, incision was located over the scar; and group III, mixed and criss-cross incision was present. The primary outcome variable of interest was to analyse co-relation between craniectomy and cranioplasty incisions.

Results

There were 45 cases of group I, 15 cases of group II and 10 cases of group III. Thirty-three patients had defect on left side, 26 had on right side, and 10 had bifrontal defect. No significant association was noted between the site and cranioplasty incision (Chi2 = 9.155, p = 0.433 and likelihood ratio = 9.487, p = 0.394).

Conclusion

Well-vascularized broad-based scalp flap that provides adequate exposure and located on healthy bone irrespective of pre-existing craniectomy scar forms the mainstay of successful cranial reconstruction.

Outcomes of Cranioplasty Reconstructions: Review of Cranioplasty Implants and Free Flap Coverage Variables that Affect Implant Exposure

BACKGROUND

Complex scalp wounds with cranial/dural involvement are challenging to reconstruct. Successful reconstruction can be achieved with cranial implants/hardware and free flap coverage. Wounds can breakdown and require revision procedures. We addressed reconstructive outcomes of different implants requiring free flaps.

OBJECTIVE

To determine the factors associated with implant exposure.

DESIGN

Multi-institutional retrospective review of 82 patients, 2000-2020, repaired with cranial implants and free flap coverage.

RESULTS

Implant exposure occurred in 13/82 (16%) reconstructions. Flap atrophy or thinning leading to implant exposure occurred in 11/82 (13%) reconstructions, including partial flap atrophy OR 0.05 (95% CI 0.0-0.35) and total flap atrophy OR 0.34 (95% CI 0.02-19.66). Revision surgeries that occurred subsequent to flap reconstruction were also associated with implant exposure (OR 0.02 (95% CI 0.0-0.19)). Implant exposure was not associated with radiation therapy, patient health history, implant type, flap type, or postoperative complications.

CONCLUSIONS

Implant exposure is associated with free flap atrophy, leading to inadequate implant coverage and the need for revision surgeries. Completing reconstruction with adequate soft tissue bulk and coverage and avoiding revision surgery may decrease the risk for implant exposure over time.

LEVEL OF EVIDENCE

4 Laryngoscope, 133:2954-2958, 2023.

A pH-neutral bioactive glass empowered gelatin-chitosan-sodium phytate composite scaffold for skull defect repair

The ideal skull defect repairing material should have good biocompatibility and mechanical properties, and contribute to osteogenesis. In this study, we designed and fabricated biodegradable, bioactive and mechanically robust porous scaffolds composed completely of biological materials. We used a gelatin-chitosan blend as the matrix, sodium phytate instead of toxic glutaraldehyde for cross-linking, and the pH-neutral bioactive glass (PSC) to improve biological activity and mechanical properties. The chitosan-gelatin-30%PSC/sodium phytate composite scaffold avoided the problems of high toxicity in conventional cross-linking agents with glutaraldehyde, the poor mechanical support of the pure chitosan or gelatin scaffold, and the mismatch of the degradation rate with bone repair, becoming a promising new candidate for skull defect repair.

Expanding Our Role in Headache Management: A Systematic Review and Algorithmic Approach to Surgical Management of Postcraniotomy Headache

BACKGROUND

Chronic postcraniotomy headache (PCH) is common and debilitating. Unfortunately, the literature on this topic is sparse without clear management algorithms. Possible etiologies of PCH include nerve injury and/or entrapment, hardware, dural adhesions, or musculoskeletal injury. The purpose of this study was to present the results of both a systematic review of the literature and a single-center case series, both of which informed the development of a novel treatment algorithm that may be applied to this patient population.

METHODS

Using Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines, we performed a systematic review of the literature, identifying articles describing the surgical management of PCH. A retrospective chart review was performed to identify patients who met the criteria for PCH treated at our institution. A patient's history and physical examination determined the etiology and management, and pain severity scores were the primary outcome measured.

RESULTS

Nineteen articles encompassing 131 patients described surgical management techniques for PCH. 83 patients (63.3%) had complete resolution of pain (χ2 = 52.1, P < 0.0001). At our institution, 19 patients underwent surgical management for PCH. A significant reduction in pain scores from 7.57 to 2.16 (P < 0.001) was demonstrated, and 84 percent of patients achieved complete or significant pain reduction.

CONCLUSIONS

Through a literature review and our own case series, we demonstrate that surgical management of PCH can achieve remarkable results. Plastic surgeons, with their expanding role in treating migraine and headaches, are well suited to manage these patients. We present an algorithmic approach to simplify the management of this common and debilitating condition.

Rates of operative intervention for infection after synthetic or autologous cranioplasty: a National Readmissions Database analysis

OBJECTIVE

The aim of this study was to characterize the clinical utilization and associated charges of autologous bone flap (ABF) versus synthetic flap (SF) cranioplasty and to characterize the postoperative infection risk of SF versus ABF using the National Readmissions Database (NRD).

METHODS

The authors used the publicly available NRD to identify index hospitalizations from October 2015 to December 2018 involving elective ABF or SF cranioplasty after traumatic brain injury (TBI) or stroke. Subsequent readmissions were further characterized if patients underwent neurosurgical intervention for treatment of infection or suspected infection. Survey Cox proportional hazards models were used to assess risk of readmission.

RESULTS

An estimated 2295 SF and 2072 ABF cranioplasties were performed from October 2015 to December 2018 in the United States. While the total number of cranioplasty operations decreased during the study period, the proportion of cranioplasties utilizing SF increased (p < 0.001), particularly in male patients (p = 0.011) and those with TBI (vs stroke, p = 0.012). The median total hospital charge for SF cranioplasty was $31,200 more costly than ABF cranioplasty (p < 0.001). Of all first-time readmissions, 20% involved surgical treatment for infectious reasons. Overall, 122 SF patients (5.3%) underwent surgical treatment of infection compared with 70 ABF patients (3.4%) on readmission. After accounting for confounders using a multivariable Cox model, female patients (vs male, p = 0.003), those discharged nonroutinely (vs discharge to home or self-care, p < 0.001), and patients who underwent SF cranioplasty (vs ABF, p = 0.011) were more likely to be readmitted for reoperation. Patients undergoing cranioplasty during more recent years (e.g., 2018 vs 2015) were less likely to be readmitted for reoperation because of infection (p = 0.024).

CONCLUSIONS

SFs are increasingly replacing ABFs as the material of choice for cranioplasty, despite their association with increased hospital charges. Female sex, nonroutine discharge, and SF cranioplasty are associated with increased risk for reoperation after cranioplasty.

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

Ten-Year Institutional Experience to Predict Risk of Calvarial Bone Flap Loss Using Long-Term Outcome Data

BACKGROUND

Calvarial bone flap (CBF) loss is a common complication following craniotomy and subsequent skull reconstruction can be challenging. Defining predictors of CBF failure not only improves patient outcomes but reduces the need for complex reconstruction often requiring plastic surgery consultation. As CBF failure can occur many years following craniotomy, this study aimed to determine risk factors of CBF loss using long-term follow-up.

MATERIALS AND METHODS

This retrospective study included patients who underwent craniotomy with CBF reinsertion between 2003 and 2013 at a tertiary academic institution. Patients were included if demographics, comorbidities, and long-term outcomes were available. Multivariable logistic regression modeled the odds of CBF failure, defined as permanent removal for bone flap-related issues. The median follow-up was 6.9 years (interquartile range: 1.8-10.8 y).

RESULTS

There were 222 patients who met inclusion criteria and underwent craniotomy with CBF reinsertion, primarily for tumor resection or intracranial pressure relief. CBF failure occurred in 76 (34.2%) patients. Up to 4 CBF reinsertions were performed in both failure and nonfailure groups. The risks of CBF loss increased with each additional CBF elevation by 17-fold (P<0.001), male sex by 3-fold (P=0.005), and tumor etiology by 3-fold (P=0.033) (C-index=0.942).

CONCLUSIONS

Each CBF reinsertion dramatically increases the risk of CBF loss. This finding may optimize patient selection and surgical planning. Early multidisciplinary discussions between plastic surgeons and neurosurgeons may avoid multiple CBF elevations and prevent the adverse sequela of high-risk calvarial reconstruction efforts.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

BACKGROUND

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

OBJECTIVE

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

METHODS

PubMed/MEDLINE database was searched for relevant articles published between 2010 and 2020. After screening, 35 articles were included. Outcomes included infection, wound problems, poor cosmesis, overall complications, duration of surgery, and length of stay. For each outcome, a frequentist network meta-analysis was conducted to compare materials used.

RESULTS

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

CONCLUSIONS

The quality of existing literature on this topic is relatively poor, almost exclusively comprised of single-center retrospective studies. There is currently not strong enough evidence available to make comprehensive conclusions regarding the risk-profiles of various cranioplasty materials across multiple outcomes. Prospective randomized trials are necessary to confirm the significant results found in this analysis and to further elucidate the differential risks of various cranioplasty materials.

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.

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.

Decision-Making in Adult Cranial Vault Reconstruction

LEARNING OBJECTIVES

After studying this article, the participant should be able to: 1. Define and classify different types of cranial defects 2. Compare both autologous and alloplastic options for reconstruction 3. Develop an optimal approach for cranial vault reconstruction in various clinical scenarios.

SUMMARY

Defects of the cranium result from various causes, including traumatic loss, neurosurgical intervention, skull tumors, and infection. Cranial vault reconstruction aims to restore both the structural integrity and surface morphology of the skull. To ensure a successful outcome, the choice of appropriate cranioplasty reconstruction will vary primarily based on the cause, location, and size of the defect. Other relevant factors that must be considered include adequacy of soft-tissue coverage, presence of infection, and previous or planned radiation therapy. This article presents an algorithm for the reconstruction of various cranial defects using both autologous and alloplastic techniques, with a comparison of their advantages and disadvantages.

Security and reliability of CUSTOMBONE cranioplasties: A prospective multicentric study

BACKGROUND

Repairing bone defects generated by craniectomy is a major therapeutic challenge in terms of bone consolidation as well as functional and cognitive recovery. Furthermore, these surgical procedures are often grafted with complications such as infections, breaches, displacements and rejections leading to failure and thus explantation of the prosthesis.

OBJECTIVE

To evaluate cumulative explantation and infection rates following the implantation of a tailored cranioplasty CUSTOMBONE prosthesis made of porous hydroxyapatite. One hundred and ten consecutive patients requiring cranial reconstruction for a bone defect were prospectively included in a multicenter study constituted of 21 centres between December 2012 and July 2014. Follow-up lasted 2 years.

RESULTS

Mean age of patients included in the study was 42±15 years old (y.o), composed mainly by men (57.27%). Explantations of the CUSTOMBONE prosthesis were performed in 13/110 (11.8%) patients, significantly due to infections: 9/13 (69.2%) (p<0.0001), with 2 (15.4%) implant fracture, 1 (7.7%) skin defect and 1 (7.7%) following the mobilization of the implant. Cumulative explantation rates were successively 4.6% (SD 2.0), 7.4% (SD 2.5), 9.4% (SD 2.8) and 11.8% (SD 2.9%) at 2, 6, 12 and 24 months. Infections were identified in 16/110 (14.5%): 8/16 (50%) superficial and 8/16 (50%) deep. None of the following elements, whether demographic characteristics, indications, size, location of the implant, redo surgery, co-morbidities or medical history, were statistically identified as risk factors for prosthesis explantation or infection.

CONCLUSION

Our study provides relevant clinical evidence on the performance and safety of CUSTOMBONE prosthesis in cranial procedures. Complications that are difficulty incompressible mainly occur during the first 6 months, but can appear at a later stage (>1 year). Thus assiduous, regular and long-term surveillances are necessary.

A systematic review of cranioplasty material toxicity in human subjects

PURPOSE

Local and systemic toxic reactions to implanted materials can result in morbidities. However, little is reported about cranioplasty implants. Therefore, we performed a systematic review on the toxicity of different materials used for cranioplasty implants.

MATERIALS AND METHODS

A systematic search was conducted by browsing the Pubmed, Embase, and Cochrane Library databases. All human studies that identified toxic (aseptic) reactions to any types of material used as cranioplasty implants or onplants, published up to January 1, 2019, were included in the review.

RESULTS

Nineteen studies were identified. Collectively, 36 patients endured some type of toxic reaction to an implanted material. Eleven studies presented several types of toxicity for PMMA cranioplasties in several tissue types. One article highlighted the risk of neurotoxicity for PMMA cranioplasty. Three articles presented toxic reactions to calcium phosphate and titanium implants. Three additional articles presented toxic reactions to PEEK, polypropylene-polyester, and polyethylene.

CONCLUSION

All materials currently used for cranioplasty showed occasional toxicity and morbidities. Therefore, none can be considered completely biologically inert. We found that aseptic inflammatory reactions have been underreported in the literature due to a high incidence of infections with questionable evidence.

Risk Factors for Postoperative Inflammatory Complications After Maxillofacial Reconstruction Using Polyether-Ether-Ketone Implants

PURPOSE

Polyether-ether-ketone (PEEK) implants are increasingly used for the reconstruction of craniomaxillofacial deformities, but limited data exist on their limitations or risk factors for complications associated with their use. The purpose of the present study was to identify risk factors for postoperative inflammatory complications (POICs) after the use of PEEK implants in craniomaxillofacial reconstruction.

METHODS

A retrospective cohort study was conducted, incorporating all patients treated with patient-specific PEEK implants at the authors' institution from August 1, 2012 to June 30, 2019. The outcome variable was the presence of POICs. The potential predictor variables were demographic, medical, anatomic, and treatment related. Statistical analysis was performed using Fisher exact tests, t tests, and multivariable logistic regression analysis where appropriate.

RESULTS

The 32 patients included in the study were composed of 68.8% men; mean age was 40.6 years. The PEEK implant was placed adjacent to the paranasal sinuses in 56.3% of patients. The indication for use was malar depression in 50.0%, orbital dystopia in 46.9%, forehead or skull defects in 21.9%, and mandibular contour deformities in 6.2%; 8 patients had more than 1 indication. The overall rate of POICs was 28.1%. Of the POICs, 66.7% were managed with incision and drainage, revision surgery, or removal and 33.3% were managed with outpatient wound care or antibiotics. Tobacco use, the presence of an intraoral incision, and the presence of multiple incisions were all associated with POICs. On multivariable analysis, tobacco use approached significance (odds ratio, 17.3 [95% confidence interval, 0.98 to 306.7]) and multiple incisions (odds ratio, 6.9 [95% confidence interval, 1.5 to 32.3]) had a statistically significant association with the occurrence of complications.

CONCLUSIONS

The present study identified several variables potentially associated with complications after the use of PEEK implants in maxillofacial reconstruction. Consideration should be given in the preoperative evaluation when a smoker is identified and when multiple incisions are planned.

Staged reconstruction of a chronically infected large skull defect using free tissue transfer and a patient-specific polyetheretherketone implant

Reconstructions of extensive composite scalp and cranial defects are challenging due to high incidence of postoperative infection and reconstruction failure. In such cases, cranial reconstruction and vascularized soft tissue coverage are required. However, optimal reconstruction timing and material for cranioplasty are not yet determined. Herein, we present a large skull defect with a chronically infected wound that was not improved by repeated debridement and antibiotic treatment for 3 months. It was successfully treated with anterolateral thigh (ALT) free flap transfer for wound salvage and delayed cranioplasty with a patient-specific polyetheretherketone implant. To reduce infection risk, we performed the cranioplasty 1 year after the infection had resolved. In the meantime, depression of ALT flap at the skull defect site was observed, and the midline shift to the contralateral side was reported in a brain computed tomography (CT) scan, but no evidence of neurologic deterioration was found. After the surgery, sufficient cerebral expansion without noticeable dead-space was confirmed in a follow-up CT scan, and there was no complication over the 1-year follow-up period.

Clinical evaluation of rapid 3D print-formed implants for surgical reconstruction of large cranial defects

BACKGROUND

To clinically evaluate 3D print-formed implant process, using cranioplasty as a proof of concept, to examine its effectiveness and utility as a method of intraoperative implant fabrication.

METHODS

Twelve patients had a 3D print-formed template created for patient-specific implant manufacture. Of these patients, 10 received intraoperatively formed polymethylmethacrylate cranioplasty implants between 2013 and 2019. The 3D print-formed implant templates produced to manufacture these patient-specific implants were generated using patient computed tomography scans and 3D printed using fused deposition modelling technology. Cosmetic and functional results were determined by participating surgeons, in conjunction with a patient questionnaire.

RESULTS

The functional results and stability of the implants were deemed to be favourable by participating surgeons. Three of the 10 patients completed a post-cranioplasty survey, all of whom judged their cosmetic results as good or excellent. At time of writing, the rate of surgical revision was zero and without clinically adverse outcomes.

CONCLUSIONS

3D print-formed implants are an effective method of patient-specific implant formation.

Long-term Effect of Cranioplasty on Overlying Scalp Atrophy

Scalp thinning over a cranioplasty can lead to complex wound problems, such as extrusion and infection. However, the details of this process remain unknown. The aim of this study was to describe long-term soft-tissue changes over various cranioplasty materials and to examine risk factors associated with accelerated scalp thinning.

Recurrent Syndrome of the Trephined in the Setting of Multiple Craniectomy and Cranioplasty

Decompressive craniectomy is an increasingly implemented intervention for relief of intracranial hypertension refractory to medical therapy. Despite its therapeutic benefit, a myriad of short and long-term complications may arise when the once fixed-volume cranial vault remains decompressed. The authors present a case of recurrent Syndrome of the Trephined in a patient undergoing repeated craniectomy and cranioplasty.A 70-year old male with history significant for smoking and chronic obstructive pulmonary disease presented with frontoparietal subdural hematoma with midline shift following a ground level fall necessitating craniotomy and hematoma evacuation. Three months postoperatively, the patient developed an infection of his craniotomy bone flap necessitating craniectomy without cranioplasty. Six weeks post-craniectomy the patient began demonstrating right sided sensorimotor deficits with word finding difficulties. Alloplastic cranioplasty was performed following resolution of infection, with resolution of neurologic symptoms 6 weeks post cranioplasty. Due to recurrent cranioplasty infections, multiple alloplastic cranioplasties were performed, each with reliable re-demonstration of neurologic symptoms with craniectomy, and subsequent resolution following each cranioplasty. Final cranioplasty was successfully performed using a new alloplastic implant in combination with latissimus muscle flap, with subsequent return of neurologic function.Decompressive craniectomy is a life-saving procedure, but carries many short- and long-term complications, including the Syndrome of the Trephined. Our case is the first published report, to our knowledge, to demonstrate recurrent Syndrome of the Trephined as a complication of craniectomy, with reliable resolution of the syndrome with restoration of the cranial vault.

Conditioning of 3D Printed Nanoengineered Ionic-Covalent Entanglement Scaffolds with iP-hMSCs Derived Matrix

Additive manufacturing is a promising method for producing customized 3D bioactive constructs for regenerative medicine. Here, 3D printed highly osteogenic scaffolds using nanoengineered ionic-covalent entanglement ink (NICE) for bone tissue engineering are reported. This NICE ink consists of ionic-covalent entanglement reinforced with Laponite, a 2D nanosilicate (nSi) clay, allowing for the printing of anatomic-sized constructs with high accuracy. The 3D printed structure is able to maintain high structural stability in physiological conditions without any significant swelling or deswelling. The presence of nSi imparts osteoinductive characteristics to the NICE scaffolds, which is further augmented by depositing pluripotent stem cell-derived extracellular matrix (ECM) on the scaffolds. This is achieved by stimulating human induced pluripotent stem cell-derived mesenchymal stem cells (iP-hMSCs) with 2-chloro-5-nitrobenzanilide, a PPARγ inhibitor that enhances Wnt pathway, resulting in the deposition of an ECM characterized by high levels of collagens VI and XII found in anabolic bone. The osteoinductive characteristics of these bioconditioned NICE (bNICE) scaffolds is demonstrated through osteogenic differentiation of bone marrow derived human mesenchymal stem cells. A significant increase in the expression of osteogenic gene markers as well as mineralized ECM are observed on bioconditioned NICE (bNICE) scaffolds compared to bare scaffolds (NICE). The bioconditioned 3D printed scaffolds provide a unique strategy to design personalized bone grafts for in situ bone regeneration.

Risk of Complications in Primary Versus Revision-Type Cranioplasty

INTRODUCTION

Cranioplasty (CP) is a multifaceted procedure in a heterogenous patient population, with a high risk for complication. However, no previous large-scale studies have compared outcomes in primary (ie, first attempt) CP versus revision CP (ie, following previous attempts). The authors, therefore, analyzed long-term outcomes of 506 consecutive primary and revision CPs, performed by a single surgeon.

METHODS

All CPs performed between 2012 and 2019 were analyzed under IRB protocol approval. Surgeries were categorized as either primary (no previous CP; n = 279) or revision CP (at least one previous CP; n = 227). Complications were defined as either major or minor. Subgroup analyses investigated whether or not CP complication risk directly correlated with the number of previous neuro-cranial surgeries and/or CP attempts.

RESULTS

The primary CP group experienced a major complication rate of 9% (26/279). In comparison, the revision CP group demonstrated a major complication rate of 32% (73/227). For the revision CP group, the rate of major complications rose with each additional surgery, from 4% (1 prior surgery) to 17% (2 prior surgeries) to 39% (3-4 prior surgeries) to 47% (≥5 prior surgeries).

CONCLUSION

In a review of 506 consecutive cases, patients undergoing revision CP had a 3-fold increase in incidence of major complications, as compared to those undergoing primary CP. These results provide critical insight into overall CP risk stratification and may guide preoperative risk-benefit discussions. Furthermore, these findings may support a center-of-excellence care model, particularly for those patients with a history of previous neuro-cranial surgeries and/or CP attempts.

The Pericranial Flap as a Salvage Procedure in Pediatric Neurosurgical Complications

ABSTRACT

The pericranium is a vascularized structure that can be used for the treatment of complex scalp and skull defects. It is also utilized as a prophylactic measure to prevent wound complications in high-risk patients. In this study, we looked at the use of the pericranial flap in pediatric patients. A retrospective chart review was done in the American University of Beirut Medical Center from February 2010 to 2020. Ten pediatric patients were identified who required either prophylactic pericranial flap (n  =  3) or for treatment of a chronic draining sinus (n =  7). Patients were followed up for an average of 23 days. There were no cases of infection, hematoma, seroma, or meningitis. Only 1 case developed dehiscence of the skin. It was managed conservatively and healed within 2 weeks. The pericranial flap is a workhorse flap for scalp and skull reconstruction, with no donor site morbidity and thus should always be considered.

Meningioma infiltrating into porous polymethylmethacrylate cranioplasty-report of a unique case

Implantation of a cranioplasty after osteoclastic craniotomy or craniectomy is one of the most common neurosurgical procedures, and polymethylmethacrylate (PMMA) is one of the most frequently applied materials for cranioplasty. This report describes the unique case of a patient with recurrent transitional meningioma WHO I that infiltrated the PMMA cranioplasty 7 years after primary surgery. We propose to restrict the use of porous PMMA as cranioplasty after the removal of convexity meningioma.

Repairing Cranial Defect With Autogenous Mandibular Outer Plate

BACKGROUND

Autogenous bone is the best material in cranioplasty because of biological advantages. Previously, skull, rib, ilium, and fibula have been used in the reconstruction of cranial defects. However, the application of autologous mandibular outer plate in the treatment of skull defect is rarely reported. This study evaluated the application of the autogenous mandibular outer plate in the reconstruction of cranial defect.

METHODS

Eleven patients who underwent cranioplasty with mandibular outer plate were recruited. Three-dimensional tomography data were collected to calculate the preoperative, immediate postoperative, and long-term follow-up volume of the bone graft area and donor bone site, and then the absorption rate and the regeneration rate of autogenous bone were analyzed.

RESULTS

The majority of the patients were satisfied with the reconstructive outcome. There are statistical differences in the volumetric measurements of the bone graft area and bone donor site at different time periods (P<0.05). The mean absorptivity of mandibular outer plate implanted in the cranial defect area was (17.30 ± 5.03)% after 3 to 24 months postoperatively, the average regeneration rate of mandibular outer plate volume was (41.65 ± 9.85)% at the same period.

CONCLUSION

This report shows that the cranioplasty with mandibular outer plate bone graft may be an optional surgical procedure.

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.

Split Calvarial Grafting for Closure of Large Cranial Defects: The Ideal Option?

Among the various cranioplasty options for reconstruction of large post-craniectomy defects, split calvarial grafting offers numerous significant advantages such as the provision of viable autogenous bone graft material comprising of living, immunocompatible bony cells that integrate fully with the skull bone bordering the cranial defect. Its potential for revascularization and subsequent integration and consolidation allows its successful use even in previously infected or otherwise compromised recipient sites. Its excellent contour match at the recipient site and low cost as compared to various alloplastic implant materials often makes it preferable to the latter. Surgeon's skill, dexterity, expertise and experience are important factors to be considered in this highly technique-sensitive procedure.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

Management and prevention of cranioplasty infections

BACKGROUND

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

METHODS

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

CONCLUSIONS

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

Polymethyl Methacrylate in Patient-Specific Implants: Description of a New Three-Dimension Technique

Polymethyl methacrylate (PMMA), an easily moldable and economical synthetic resin, has been used since the 1940s. In addition, PMMA has good mechanical properties and is one of the most biocompatible alloplastic materials currently available. The PMMA can serve as a spacer and as a delivery vehicle for antibiotics. Prior studies have indicated that no significant differences in infection rates exist between autologous and acrylic cranioplasty. Although inexpensive, the free-hand cranioplasty technique often yields unsatisfactory cosmetic results. In the present study, the application of a recently developed, economic modality for the perioperative application, and molding of PMMA to ensure a precise fit in 16 patients using computer-aided design, computer-aided manufacturing, and rapid prototyping was described.The mean defect size was 102.0 ± 26.4 cm. The mean volume of PMMA required to perform the cranioplasty procedure was 51 mL. The cost of PMMA was approximately 6 Euro (&OV0556;) per mL. The costs of fabricating the implants varied from 119.8 &OV0556; to 1632.0 &OV0556; with a mean of 326.4 &OV0556; ± 371.6. None of the implants required removal during the follow-up period.

Evaluation of neurosurgical implant infection rates and associated pathogens: evidence from 1118 postoperative infections

OBJECTIVE

Various implanted materials are used in neurosurgery; however, there remains a lack of pooled data on infection rates (IRs) and infective bacteria over past decades. The goal of this study was to investigate implant infections in neurosurgical procedures in a longitudinal retrospective study and to evaluate the IRs of neurosurgically implanted materials and the distribution of pathogenic microorganisms.

METHODS

A systematic literature search was conducted using PubMed and Web of Science databases for the time period between 1968 and 2018. Neurosurgical implant infections were studied in 5 subgroups, including operations or diseases, implanted materials, bacteria, distribution by country, and time periods, which were obtained from the literature and statistically analyzed. In this meta-analysis, statistical heterogeneity across studies was tested by using p values and I2 values between studies of associated pathogens. Egger’s test was used for assessing symmetries of funnel plots with Stata 11.0 software. Methodological quality was assessed to judge the risk of bias according to the Cochrane Handbook.

RESULTS

A total of 22,971 patients from 227 articles satisfied the study’s eligibility criteria. Of these, 1118 cases of infection were reported, and the overall IR was 4.87%. In this study, the neurosurgical procedures or disorders with the top 3 IRs included craniotomy (IR 6.58%), cranioplasty (IR 5.89%), and motor movement disorders (IR 5.43%). Among 13 implanted materials, the implants with the top 3 IRs included polypropylene-polyester, titanium, and polyetheretherketone (PEEK), which were 8.11%, 8.15%, and 7.31%, respectively. Furthermore, the main causative pathogen was Staphylococcus aureus and the countries with the top 3 IRs were Denmark (IR 11.90%), Korea (IR 10.98%), and Mexico (IR 9.26%). Except for the low IR from 1998 to 2007, the overall implant IR after neurosurgical procedures was on the rise.

CONCLUSIONS

In this study, the main pathogen in neurosurgery was S. aureus, which can provide a certain reference for the clinic. In addition, the IRs of polypropylene-polyester, titanium, and PEEK were higher than other materials, which means that more attention should be paid to them. In short, the total IR was high in neurosurgical implants and should be taken seriously.

Subtotal calvarial vault reconstruction utilizing a customized polyetheretherketone (PEEK) implant with chimeric microvascular soft tissue coverage in a patient with syndrome of the trephined: A case report

The syndrome of the trephined is a neurologic phenomenon that manifests as sudden decline in cognition, behavior, and sensorimotor function due to loss of intracranial domain. This scenario typically occurs in the setting of large craniectomy defects, resulting from trauma, infection, and/or oncologic extirpation. Cranioplasty has been shown to reverse these symptoms by normalizing cerebral hemodynamics and metabolism. However, successful reconstruction may be difficult in patients with complex and/or hostile calvarial defects. We present the case of a 48-year-old male with a large cranial bone defect, who failed autologous cranioplasty secondary to infection, and developed rapid neurologic deterioration leading to a near-vegetative state. Following debridement and antibiotic therapy, delayed cranioplasty was accomplished using a polyetheretherketone (PEEK) implant with free chimeric latissimus dorsi/serratus anterior myocutaneous flap transfer for vascularized resurfacing. Significant improvements in cognition and motor skill were noted in the early postoperative period. At 6-month follow-up, the patient had regained the ability to speak, ambulate and self-feed—correlating with evidence of cerebral/ventricular re-expansion on computed tomography. Based on our findings, we advocate delayed alloplastic implantation with total vascularized soft tissue coverage as a viable alternative for reconstructing extensive, hostile calvarial defects in patients with the syndrome of the trephined.

Association between metal hypersensitivity and implant failure in patients who underwent titanium cranioplasty

OBJECTIVE

Digitally designed titanium plates are commonly used for the reconstruction of craniofacial defects, although implant exposure (referred to as failure) is one of the major complications. Metal hypersensitivities have been suggested as possible causes of implant failure of orthopedic, intravascular, gynecological, and dental devices, yet there has been no consensus on the requirement for allergy screening before cranioplasty.

METHODS

In this study, the authors prospectively investigated the prevalence of metal hypersensitivity in patients for whom cranioplasty is planned and assess its relationship with titanium implant failure (exposure).

RESULTS

Based on records from 207 included patients, 39.61% of patients showed hypersensitivity to at least one kind of metal. Approximately one-quarter (25.12%) of patients had multiple metal allergies. Co, Cd, and Zn were the 3 most frequently identified metal hypersensitivities. No allergy to titanium was detected in this study. The overall incidence of cranioplasty implant failure was 5.31% (11 of 207). Patients showing hypersensitivities to more than 3 kinds of metal had higher risks of titanium plate exposure.

CONCLUSIONS

Based on their findings, the authors suggest that routine allergy screening be performed before titanium plate cranioplasty. For patients with hypersensitivities to more than 3 metals, alternative materials, such as polyetheretherketone, should be considered for cranioplasty.

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.

The Timing of Alloplastic Cranioplasty in the Setting of Previous Osteomyelitis

BACKGROUND

Management of cranial osteomyelitis is challenging and often includes débridement of infected bone and delayed alloplastic cranioplasty. However, the optimal interval between the removal of infected bone and definitive reconstruction remains controversial. The authors investigated the optimal time for definitive reconstruction and factors influencing cranioplasty reinfection.

METHODS

A retrospective review of 111 alloplastic cranioplasties for osteomyelitis between 2002 and 2015 was performed. Patients were divided into four subgroups based on timing of reconstruction: group 1, less than 3 months; group 2, 3 to 6 months; group 3, 6 to 12 months; and group 4, more than 12 months. Multivariate logistic regression was used to calculate the probability of cranioplasty reinfection based on risk factors. Median follow-up was 45.9 months (range, 12.4 to 136.9 months).

RESULTS

The combined reinfection rate was 23.4 percent. The reinfection rate in group 1 was 39.6 percent; group 2, 12.5 percent; group 3, 8.0 percent; and group 4, 0.0 percent (p < 0.001). The mean interval between the infected bone removal and cranioplasty was shorter in patients with reinfection than in patients without reinfection (2.2 ± 3.9 months versus 6.1 ± 8.3 months; p < 0.001). The strongest independent predictors of reinfection were chemotherapy (OR, 10.1; 95 percent CI, 2.9 to 35.2), composite defect requiring scalp reconstruction at the time of cranioplasty (OR, 3.3; 95 percent CI, 1.2 to 8.9), and early reconstruction. Each month of delay in reconstruction reduced the reinfection rate by 10 percent (OR, 0.9 per each month of delay; 95 percent CI, 0.8 to 1.0). Cranioplasty material was not significant.

CONCLUSIONS

Early alloplastic cranioplasty following osteomyelitis carries an unacceptably high risk of reinfection. This risk decreases by 10 percent with each month of delay. The authors' regression model can be used to predict the probability of reinfection for all time periods.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, III.

Two-Staged Frontal Bone Defect Reconstruction: Perioperative Assessment of Scalp Vascularization Using Near-Infrared Indocyanine Green Video Angiography (Visionsense Iridium)

BACKGROUND

Head trauma and neurosurgical-related osteomyelitis are common causes of cranial bone defect. Even though cranioplasty is considered a safe and well-consolidated procedure, there are still some issues about the flap's vascularization assessment. In this paper we describe a 2-staged cranioplasty procedure, focusing on the perioperative evaluation of the skin flap vascularization. Our goal is to assess if the skin flap's perfusion measurement with indocyanine green fluorescence can be considered a reliable method to predict good outcome in cranioplasties.

CASE DESCRIPTION

A 50-year-old patient presented with a wide frontal bone defect due to a prior surgery-related osteomyelitis. During the first operation, a tissue expander was placed under the scalp in order to grant an appropriate skin stretching. During the second operation the defect was repaired with a custom-made prosthesis after tissue expander removal. During all procedures, vascular integrity of the skin flap was intraoperatively assessed by means of indocyanine green fluorescence.

CONCLUSIONS

Surgical procedures were well tolerated; at 1 year of follow-up the cosmetic defect was unremarkable. Indocyanine green fluorescence can be a good aid to predict the probability of the skin flap survival by measuring its perfusion.

Multi-stage Preparation for the Repair of Complicated Skull Defects

Cranioplasty following decompressive craniectomy is highly associated with complications. Methods for avoiding these complications have been well-documented; however, approaching reconstruction through the previous incision, especially if it was on or very near the bone defect, can sometimes lead to wound dehiscence and infection, with exposure of the artificial bone. For such complicated cases, we propose a multi-staged preparation that includes creating a delayed skin flap for the actual skull reconstruction. Flap was elevated in three stages, with 4 week intervals between each stage to allow for adequate blood supply. Cranioplasty using custom-made implants was then performed. Four patients (age range, 10–25 years) were prepared for skull reconstruction using this technique. During follow-up period for 12 months, no complications, including infections, exposure of the artificial bone, or flap necrosis, were observed. Despite the multiple stages required, we consider that our technique makes a significant contribution to the literature because it suggests a technique for cranioplasty following decompressive craniectomy that may avoid many of the complications following such cranioplasty using current methods.

Cranioplasty Using Autologous Bone versus Porous Polyethylene versus Custom-Made Titanium Mesh : A Retrospective Review of 108 Patients

Objective

The purpose of this study was to compare the cosmetic outcome and complications after cranioplasty (CP) due to three different implant materials, and analyze the mean implant survival and cumulative survival rate based on these results.

Methods

We reviewed 108 patients retrospectively who underwent CP between January 2014 and November 2016. Autologous bone (AB; 45 patients) and synthetic materials with porous polyethylene (PP; 32 patients) and custom-made 3-dimensional printed titanium mesh (CT; 31 patients) were used as implants.

Results

Regardless of implanted materials, more than 89.8% of the CP patients were satisfied with the cosmetic outcome. No statistically significant difference was observed among the three groups. The overall postoperative complication rates of each group were 31.1% in the AB group, 15.6% in the PP group and 3.2% in the CT group. The CT group showed lower complication rates compared with AB and PP groups (χ²-test : AB vs. PP, p=0.34; AB vs. CT, p=0.00; PP vs. CT, p=0.03). The AB and PP groups demonstrated a higher post-CP infection rate (11.1% and 6.3%) than the CT group (3.2%). However, no significant difference in the incidence of post-CP infection was observed among the three groups. The PP and CT groups demonstrated a higher mean implant survival time and cumulative survival rate than the AB group at the last follow-up (p<0.05).

Conclusion

In comparison with AB and PP, cranioplasty with CT shows benefits in terms of lower post-CP complication, less intraoperative bleeding loss, shorter operation time and in-hospital stay. The PP and CT groups showed higher implant survival time and cumulative survival rate compared with the AB group.

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.