Multidisciplinary approach for improved outcomes in secondary cranial reconstruction: introducing the pericranial-onlay cranioplasty technique

Time-to-surgery for traumatic brain injury in the hyperacute period: a systemic review and meta-analysis

OBJECTIVE

To study the functional outcomes of traumatic brain injury (TBI) patients who have undergone surgical intervention in the hyperacute phase (<24 h).

DATA SOURCES

Cochrane Library, PubMed, Embase, Medline and Web of Science databases.

REVIEW METHODS

A meta-analysis of 7 trials involving 237 patients was performed. Patients were categorized into two groups based on time to surgery: within 6 h and within 24 h. Patients were also categorized into developed and developing regions. Effect estimates were calculated using a fixed-effects model and heterogeneity was assessed with Cochrane I² statistic.

RESULTS

Our findings revealed that those who underwent neurosurgery in the hyperacute phase of TBI were at risk of adverse outcomes. The odds ratio (OR) was 1.50 (95% CI 1.03-2.19). Subgroup analysis demonstrated that TBI patients who underwent surgery within 6 h were at a greater risk of adverse effects (OR, 1.72; 95% CI, 1.08-2.74). Moreover, a greater risk was observed in developing regions (OR, 2.33; 95% CI, 0.97-5.58).

CONCLUSION

Earlier neurosurgical intervention in the acute phase of TBI might result in higher incidence of adverse events. Surgery would be postponed for TBI patients whose initial GCS score is greater than 8 during the hyperacute period.

Review of Functional Cranioplasty and Implantable Neurotechnology

Cranioplasty for secondary reconstruction of cranial defects has historically focused on simply replacing the missing cranial bone to restore cerebral protection and fluid dynamics, but recent innovations have led to the development of customized cranial implants that address both bone and soft tissue deficits while avoiding postoperative complications such as temporal hollowing. In addition, customized cranial implants have incorporated implantable neurotechnology like ventriculostomy shunts, intracranial pressure monitoring devices, and medicine delivery systems within low-profile designs to convert previously "basic" implants into "smart" implants for added functionality. These "smart" implants aim to reduce complications and improve patient outcomes by leveraging the cranial space to house advanced technologies, providing benefits such as real-time biosensing, and treatment of chronic neurological conditions. This review outlines the progression of cranioplasty from basic bone replacement to functional implants with embedded neurotechnologies, highlighting the multidisciplinary approaches that enhance surgical outcomes and patient quality of life.

Can we do better at measuring patient-reported outcomes after cranioplasty? A systematic review

Measuring quality of life (QOL) after cranioplasty is increasingly evident as a necessary component of patient-centered care. For data to be useful in clinical decision-making and approval of new therapies, studies must utilize valid and reliable instruments. Our objective was to critically appraise studies evaluating QOL in adult cranioplasty patients and determine validity and relevance of the patient-reported outcome measures (PROMs) used. Electronic databases of PubMed, Embase, CINAHL, and PsychINFO were used to identify PROMs measuring QOL in adult patients with cranioplasty. The methodological approach, cranioplasty outcomes, and domains measured by the PROMs were extracted and summarized descriptively. A content analysis of the identified PROMs was completed to identify the concepts measured. From 2236 articles identified, 17 articles containing eight QOL PROMs met the inclusion criteria. None of the PROMs was specifically validated or developed for adults undergoing cranioplasty. The QOL domains included physical health, psychological health, social health, and general QOL. These four domains encompassed 216 total items among the PROMs. Appearance was only assessed in two PROMs. To our knowledge, there are currently no validated PROMs that comprehensively measure appearance, facial function, and adverse effects in adults undergoing cranioplasty. There is an urgent need to develop PROMs to measure QOL outcomes rigorously and comprehensively in this patient population to inform clinical care, research, and quality improvement initiatives. Findings from this systematic review will be used to derive an outcome instrument containing important concepts related to QOL in patients who undergo cranioplasty.

Clinical and patient-reported outcome after patient-specific 3D printer-assisted cranioplasty

Various cranioplasty techniques exist for the reconstruction of cranial bone defects. Patient-specific implants can be produced in-house using a recently developed 3D printer-assisted cranioplasty technique. However, the resulting cosmetic outcomes from the patient's perspective are underreported. With our case series, we aim to present the clinical outcome, morbidity rate, patient-reported cosmetic results, and cost-effectiveness of patient-specific3D printer-assisted cranioplasty technique. This is a consecutive retrospective case series of adult patients undergoing cranioplasty using the patient-specific 3D printer-assisted technique. As primary endpoint, the functional outcome based on modified Rankin scale (mRS) at discharge and follow-up was assessed. A prospective telephone survey was conducted to collect and provide patient-reported outcomes. Thirty-one patients underwent patient-specific 3D printer-assisted cranioplasty, mostly to reconstruct frontotemporoparietal (61.3%) and frontotemporal defects with orbital involvement (19.4%). Good functional outcome (mRS ≤ 2) at discharge and during the last follow-up was achieved in 54.8% (n = 17) and 58.1% (n = 18) patients. Overall, the rate of clinically relevant surgery-related complications was 35.5% (n = 11). Postoperative epidural hematoma/collection (16.1%) and infections (12.9%) were the most frequent complications. Permanent morbidity occurred in one patient (3.2%) with postoperative acute ipsilateral vision loss after frontotemporal cranioplasty with orbital involvement. No surgery-related mortality occurred. The mean patient-reported cosmetic satisfaction score was 7.8 ± 1.5, with 80% of patients reporting satisfying or very satisfying cosmetic results. No significant differences were seen between the different defect localization regarding the cosmetic outcome. The mean manufacturing costs of a patient-specific 3D printer-assisted implant ranged from 748 to 1129 USD. Based on our case series, patient-specific 3D printer-assisted cranioplasty is cost-effective and leads to satisfying cosmetic results, especially in large defects and/or defects with complex geometry.

Single-stage cranioplasty with customized polyetheretherketone implant after tumor resection using virtual reality and augmented reality for precise implant customization and placement: illustrative case

BACKGROUND

Cranioplasties are routinely performed to restore cosmesis and to protect intracranial contents after trauma, resection of tumors, or other pathologies. Traditionally done as a second-stage procedure, new single-stage cranioplasty protocols have been developed to minimize recovery periods, decrease complications, and improve patient satisfaction. These protocols, however, still require the use of larger than planned implants or use larger than ideal incisions to accommodate three-dimensional (3D) templates, which may not be optimal in regions with complex bony anatomy.

OBSERVATIONS

A 50-year-old woman with a painful and progressively enlarging hemangioma of the left frontal bone underwent a single-stage resection followed by custom cranioplasty using a new extended reality (XR)-based workflow. Excellent cosmetic results, decreased operative time, and a feasible workflow were achieved.

LESSONS

The use of an XR-based visualization platform allows the surgeon to treat lesions and perform custom cranioplasties in one session while avoiding common pitfalls of current single-stage workflows, such as increased operative times for tailoring implants, as well as minimizing the use of 3D overlay models, which may not appropriately conform to complex regional bony anatomy intraoperatively.

First-In-Human Experience With Integration of Wireless Intracranial Pressure Monitoring Device Within a Customized Cranial Implant

BACKGROUND

Decompressive craniectomy is a lifesaving treatment for intractable intracranial hypertension. For patients who survive, a second surgery for cranial reconstruction (cranioplasty) is required. The effect of cranioplasty on intracranial pressure (ICP) is unknown.

OBJECTIVE

To integrate the recently Food and Drug Administration-approved, fully implantable, noninvasive ICP sensor within a customized cranial implant (CCI) for postoperative monitoring in patients at high risk for intracranial hypertension.

METHODS

A 16-yr-old female presented for cranioplasty 4-mo after decompressive hemicraniectomy for craniocerebral gunshot wound. Given the persistent transcranial herniation with concomitant subdural hygroma, there was concern for intracranial hypertension following cranioplasty. Thus, cranial reconstruction was performed utilizing a CCI with an integrated wireless ICP sensor, and noninvasive postoperative monitoring was performed.

RESULTS

Intermittent ICP measurements were obtained twice daily using a wireless, handheld monitor. The ICP ranged from 2 to 10 mmHg in the supine position and from -5 to 4 mmHg in the sitting position. Interestingly, an average of 7 mmHg difference was consistently noted between the sitting and supine measurements.

CONCLUSION

This first-in-human experience demonstrates several notable findings, including (1) newfound safety and efficacy of integrating a wireless ICP sensor within a CCI for perioperative neuromonitoring; (2) proven restoration of normal ICP postcranioplasty despite severe preoperative transcranial herniation; and (3) proven restoration of postural ICP adaptations following cranioplasty. To the best of our knowledge, this is the first case demonstrating these intriguing findings with the potential to fundamentally alter the paradigm of cranial reconstruction.

A Standard Algorithm for Reconstruction of Scalp Defects With Simultaneous Free Flaps in an Interdisciplinary Two-Team Approach

Reconstructions of complex scalp after ablative resection or by post-traumatic tissue loss, can present difficulties regarding recipient vessel selection, functional, and aesthetic outcome. The harvesting method for many microvascular free flaps requires a need for changing patients position during surgery and makes a simultaneous interdisciplinary two-team approach complicated, which is a major disadvantage regarding safety and operation time. The ideal flap for scalp reconstruction has yet to be described, although the microvascular latissimus dorsi flap is frequently referred to as the first choice in this context, especially after resection of large defects. The purpose of this study is to compare two different microvascular free flaps for a simultaneous scalp reconstruction in an interdisciplinary two-team approach applying a standardized algorithm. All consecutively operated complex scalp defects after ablative surgery from April 2017 until August 2018 were included in this retrospective study. The indications were divided into neoplasm or wound healing disorder. Two microvascular flaps (latissimus dorsi or parascapular flap) were used to cover the soft tissue component of the resulting defects. Seventeen patients met the inclusion criterion and were treated in an interdisciplinary two-team approach. Skull reconstruction with a CAD/CAM implant was performed in 10 cases of which four were in a secondary stage. Nine patients received a parascapular flap and eight patients were treated with latissimus dorsi flap with split thickness skin graft. Anastomosis was performed with no exception to the temporal vessels. One parascapular flap had venous insufficiency after 1 week followed by flap loss. One latissimus dorsi flap had necrosis of the serratus part of the flap. All other flaps healed uneventful and could be further treated with adjuvant therapy or CAD/CAM calvarial implants. Regarding overall complications, flap related complications, flap loss, and inpatient stay no statistical differences were seen between the diagnosis or type of reconstruction. The parascapular flap seems to be a good alternative for reconstruction of complex tumor defects of the scalp besides the latissimus dorsi flap. Stable long-term results and little donor site morbidity are enabled with good aesthetic outcomes and shorter operation time in an interdisciplinary two-team approach.

Three-Dimensional Craniofacial Bone Reconstruction With SmartBone on Demand

This is a report of a 34-year-old male lacking of bone development in the frontal and orbital part of the skull due to a surgical removal of a right orbital-front osteoma at the age of 5. The integrity of the craniofacial district was important for the young patient also for social acceptance and self-esteem.Based on computed tomography patient images, a skull model was reconstructed, both digitally and on 3-dimensional real model, to best design the needed bone graft. Defect wide extension and surface curvature called for the use of the puzzle technique, where the whole graft is composed by several elements, mechanically slotting into each other. The realization was made possible thanks to the use of a composite xenohybrid bone substitute specifically developed for reconstructive surgery (SmartBone, by Industrie Biomediche Insubri SA). SmartBone technology allowed the realization of custom-made grafts which perfectly joined each other and fitted the bone defect thanks to mechanical strength, also at low thicknesses and wide extensions.The postoperative course was uneventful and computed tomography scans showed new bone formation and complete calvaria continuity already 10 months after surgery, with no signs of inflammation over the entire follow-up.This case study represents a proof of concept that SmartBone on Demand custom-made bone grafts, together with puzzle technique, are effective, easy to handle and provide final excellent functional and aesthetic results.

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.

Full-Thickness Skin Grafting for Local Defect Coverage Following Scalp Adjacent Tissue Transfer in the Setting of Cranioplasty

INTRODUCTION

Numerous techniques have been described to overcome scalp deficiency and high-tension closure at time of cranioplasty. However, there is an existing controversy, over when and if a free flap is needed during complex skull reconstruction (ie, cranioplasty). As such the authors present here our experience using full-thickness skin grafts (FTSGs) to cover local defects following scalp adjacent tissue transfer in the setting of cranioplasty.

METHODS

By way of an institutional review board-approved database, the authors identified patients treated over a 3-year period spanning January 2015 to December 2017, who underwent scalp reconstruction using the technique presented here. Patient demographics, clinical characteristics, technical details, outcomes, and long-term follow up were statistically analyzed for the purpose of this study.

RESULTS

Thirty-three patients, who underwent combined cranioplasty and scalp reconstruction using an FTSG for local donor site coverage, were identified. Twenty-five (75%) patients were considered to have "high complexity" scalp defects prior to reconstruction. Of them, 12 patients (36%) were large-sized and 20 (60%) medium-sized; 21 (64%) grafts were inset over vascularized muscle or pericranium while the remaining grafts were placed over bare calvarial bone. In total, the authors found 94% (31/33) success for all FTSGs in this cohort. Two of the skin grafts failed due to unsuccessful take. Owing to the high rate of success in this series, none of the patient's risk factors were found to correlate with graft failure. In addition, the success rate did not differ whether the graft was placed over bone verses over vascularized muscle/pericranium.

CONCLUSION

In contrary to previous studies that have reported inconsistent success with full-thickness skin grafting in this setting, the authors present a simple technique with consistent results-as compared to other more complex reconstructive methods-even in the setting of highly complex scalp reconstruction and simultaneous cranioplasty.

Seizures Following Cranioplasty: Risk Factors and Prevention Exploration

BACKGROUND

The aim of this study was to identify risk factors and explore the possible prevention measures for seizures following cranioplasty.

METHODS

The authors performed a retrospective review of 142 consecutive patients who underwent cranioplasty following craniectomy for trauma or cerebral hemorrhage in Dezhou People's Hospital between January 2010 and January 2017. Patients who were diagnosed with aneurysms, arteriovenous malformations, cerebral infarction, and tumors (14), had seizures prior to cranioplasty (9) and those lost to follow-up (7) were excluded. Patients did not use antiepilepsy drugs from treatment of postcranioplasty seizures. The median follow-up time was 51.11 ± 31.59 months (range: 17-98 months). Analyses were performed on a database tracking age, sex, reason for craniectomy, operative time, time between operations, presence of dural substitute, diabetic status, hypertensive status, tobacco use, alcohol use, location of cranioplasty, classification, time and times of seizures following cranioplasty development.

RESULTS

One hundred twelve patients met study criteria. The overall rate of seizures following cranioplasty was 35.7% (40 out of 112 patients). There were no statistically significant associations between postcranioplasty seizures and sex, age, location of cranioplasty, cranioplasty materials, or dural substitute used in craniectomy. Postcranioplasty seizure frequency differed significantly according to reasons for depressive craniectomy. The incidence of postcranioplasty seizures was significantly higher in the first year than in later years. Incidence decreased progressively in subsequent years.

CONCLUSION

Incidence of seizures following cranioplasty was associated with the reason for depressive craniectomy.

Adult Cranioplasty Reconstruction With Customized Cranial Implants: Preferred Technique, Timing, and Biomaterials

INTRODUCTION

Complex cranial defects requiring delayed reconstruction present numerous challenges. Delayed cranioplasties accompany frequent complications approaching an incidence of 35 to 40%. Therefore, the authors sought to collate their experience in hopes of sharing their perspective on several topics including technique, timing, and preferred biomaterials.

METHODS

The authors' 5-year consecutive experience over 430 customized cranial implants is described herein. Since its inception in 2012, the authors' team has employed the pericranial-onlay cranioplasty technique instead of the standard epidural approach. Optimal timing for cranioplasty is determined using objective criteria such as scalp healing and parenchymal edema, close collaboration with neuroplastic surgery, conversion from autologous bone to sterile implant in instances of questionable viability/storage, and the first-line use of solid poly(methylmethacrylate) implants for uncomplicated, delayed cases, first-line porous polyethylene (MEDPOR) implants for single-stage cranioplasty, and first-line polyether-ether-ketone implants for cases with short notice. Furthermore, the use of the pterional design algorithm with temporal bulking for all customized implants has helped to correct and/or prevent temporal hollowing deformities.

RESULTS

The authors' team has observed a three-fold reduction in reported complications as compared with the existing literature, with a major complication rate of 11%. The multidisciplinary center has provided an optimal stage for synergy and improved outcomes versus standard cranioplasty techniques.

CONCLUSION

Secondary cranial reconstruction, or cranioplasty, can be challenging due to numerous reasons. These best practices, developed in collaboration with neuroplastic surgery and neurosurgery, appear to encompass the largest published experience to date. The authors find this approach to be both safe and reliable.

Pedicle Galeo-pericranial Flap Augmentation in Salvage Frontotemporal Cranioplasty: Additional 'Neurosurgeon-friendly' Reconstruction Technique of Aesthetic Neurosurgery in Superficial Temporal Artery Branch Compromised Host

This technical note aims to demonstrate the usefulness, indications and its limitations of augmentation technique by bipedicle galeo-pericranial rotation flap and by monopedicle galeo-pericranial flap, both in STA (superficial temporal artery) branch compromised hosts in salvage frontotemporal cranioplasty. Although these flaps are not always idealistically vascularized owing to accidental injuries to the STA branches during previous surgeries, they are properly augmenting after salvage frontotemporal craniotomy when infection is not active. The procedure is indicated for salvage frontotemporal craniotomy when vasculature is needed at the surgical site, such as beneath the skin incision line in a thin injured scalp, onto the titanium plates or beneath the fragile fibrous scar. We do not apply this technique by neurosurgeons alone where infection is active or if the host is irradiated. This technique is recommended as a reconstructive aesthetic neurosurgical procedure. It is a ‘neurosurgeon-friendly’ simple procedure, as it does not require any special tools or complicated techniques.

Decompressive Craniectomy With Bifrontal Coronal Incision in the Management of Fronto-Temporal Contusion and Laceration for Early Cranioplasty

The present study aims to explore the effectiveness of decompressive craniectomy with bifrontal coronal incision in the management of severe contusion and laceration of bilateral fronto-temporal lobes, as well as the outcomes of early cranioplasty. The authors performed the bifrontal decompressive craniectomy on 56 patients with contusion and laceration of bilateral frontal and temporal lobes, and their follow-up treatment outcomes were tracked within 6 months using Glasgow Outcome Scale. The results showed that 33 patients (out of 56, 58.9%) have recovered, 12 patients (out of 56, 21.4%) have moderate defects, 5 patients (out of 56, 8.9%) have severe defects, 3 patients (out of 56, 5.3%) stayed in persistent vegetative status, and the remaining 3 patients (out of 56, 5.3%) have been dead. There was no persistent temporal hollowing. No patients required revision surgery with modified titanium mesh in this study. Particularly, 28 patients have successfully accepted the early cranioplasty with bone flap or computer-assisted design titanium mesh, and showed good recovery. These results together indicated that the decompressive craniectomy with bifrontal coronal incision in the management of severe contusion and laceration of bilateral fronto-temporal lobes can significantly relieve the comorbidity of intracranial hypertension, and improve the prognosis obviously, thus finally increasing the probability of successful rescue and decreasing the probability of mortality and disability.

Bone flap salvage in acute surgical site infection after craniotomy for tumor resection

Craniotomy surgical site infections are an inherent risk and dreaded complication for the elective brain tumor patient. Sequelae can include delays in resumption in adjuvant treatments for multiple surgeries if staged cranioplasty is pursued. Here, the authors review their experience in operative debridement of surgical site infections with single-stage reimplantation of the salvaged craniotomy bone flap. A prospectively maintained database of a single surgeon's neuro-oncology patients from 2009 to 2017 (JRF) was queried to identify 11 patients with surgical site infection after craniotomy for tumor resection. All patients underwent a protocol of aggressive operative debridement including drilling the bone edges and intraoperative flap sterilization with single-stage reimplantation, followed by tailored-antibiotic therapy. Ten of the 11 patients with frankly contaminated bone flaps from surgical site infection were able to be salvaged in a single-stage procedure. Five of these patients underwent adjuvant chemotherapy and/or radiation without secondary complication. There was one treatment failure in a delayed fashion which required additional surgery for craniectomy; however, this occurred after adjuvant treatment was administered. Surgical debridement and bone flap salvage is safe and cost-effective in managing acute surgical site infections after craniotomy for tumors. Additionally, this practice is likely beneficial in expediting the resumption of cancer therapy.

Review of Cranioplasty after Decompressive Craniectomy

Cranioplasty is an in evitable operation conducted after decompressive craniectomy (DC). The primary goals of cranioplasty after DC are to protect the brain, achieve a natural appearance and prevent sinking skin flap syndrome (or syndrome of the trephined). Furthermore, restoring patients' functional outcome and supplementing external defects helps patients improve their self-esteem. Although early cranioplasty is preferred in recent year, optimal timing for cranioplasty remains a controversial topic. Autologous bone flaps are the most ideal substitute for cranioplasty. Complications associated with cranioplasty are also variable, however, post-surgical infection is most common. Many new materials and techniques for cranioplasty are introduced. Cost-benefit analysis of these new materials and techniques can result in different outcomes from different healthcare systems.

Interactive reconstructions of cranial 3D implants under MeVisLab as an alternative to commercial planning software

In this publication, the interactive planning and reconstruction of cranial 3D Implants under the medical prototyping platform MeVisLab as alternative to commercial planning software is introduced. In doing so, a MeVisLab prototype consisting of a customized data-flow network and an own C++ module was set up. As a result, the Computer-Aided Design (CAD) software prototype guides a user through the whole workflow to generate an implant. Therefore, the workflow begins with loading and mirroring the patients head for an initial curvature of the implant. Then, the user can perform an additional Laplacian smoothing, followed by a Delaunay triangulation. The result is an aesthetic looking and well-fitting 3D implant, which can be stored in a CAD file format, e.g. STereoLithography (STL), for 3D printing. The 3D printed implant can finally be used for an in-depth pre-surgical evaluation or even as a real implant for the patient. In a nutshell, our research and development shows that a customized MeVisLab software prototype can be used as an alternative to complex commercial planning software, which may also not be available in every clinic. Finally, not to conform ourselves directly to available commercial software and look for other options that might improve the workflow.

Cranial Reconstruction Using Autologous Bone and Methylmethacrilate

BACKGROUND

Having in mind the importance of reconstruction of the calvaria, our goal was to compare the complication rates following the use of autologous bone and methylmethacrilate grafts, and explain the factors influencing them.

METHODS

The authors collected information of all the patients undergoing cranial reconstructive surgery (N = 149) at the Military Medical Academy in Belgrade. Procedures were performed either using a craniotomy bone flap, removed and replaced in the same act, or using methylmethacrilate. These 2 groups were compared using the Chi-squared test, controlling for the confounding influence of the size of the defect.

RESULTS

Intracranial neoplasms were the cause for the reconstruction in 71.1% of patients. The total complication rate was 7.4%, while the infection rate was 5.4%. The infection rate was significantly higher in those procedures done using methylmethacrilate (11.3% compared with 2.1%, P = 0.017), but when controlling for the confounding effect of the size of the defect treated, the difference in infection rate was significant only in large defects (13.9% compared with 2%, P = 0.031), while for small defects the difference was not statistically significant.

CONCLUSIONS

Our study suggests that the material used for reconstruction of calvaria influences the infection rate only in large and complicated defects. Considering the importance of the reconstruction, further studies should explore and confirm the role of material type on the rate of complications.

Evaluation of laser bacterial anti-fouling of transparent nanocrystalline yttria-stabilized-zirconia cranial implant

BACKGROUND AND OBJECTIVE

The development and feasibility of a novel nanocrystalline yttria-stabilized-zirconia (nc-YSZ) cranial implant has been recently established. The purpose of what we now call "window to the brain (WttB)" implant (or platform), is to improve patient care by providing a technique for delivery and/or collection of light into/from the brain, on demand, over large areas, and on a chronically recurring basis without the need for repeated craniotomies. WttB holds the transformative potential for enhancing light-based diagnosis and treatment of a wide variety of brain pathologies including cerebral edema, traumatic brain injury, stroke, glioma, and neurodegenerative diseases. However, bacterial adhesion to the cranial implant is the leading factor for biofilm formation (fouling), infection, and treatment failure. Escherichia coli (E. coli), in particular, is the most common isolate in gram-negative bacillary meningitis after cranial surgery or trauma. The transparency of our WttB implant may provide a unique opportunity for non-invasive treatment of bacterial infection under the implant using medical lasers.

STUDY DESIGN/MATERIALS AND METHODS

A drop of a diluted overnight culture of BL21-293 E. coli expressing luciferase was seeded between the nc-YSZ implant and the agar plate. This was followed by immediate irradiation with selected laser. After each laser treatment the nc-YSZ was removed, and cultures were incubated for 24 hours at 37 °C. The study examined continuous wave (CW) and pulsed wave (PW) modes of near-infrared (NIR) 810 nm laser wavelength with a power output ranging from 1 to 3 W. During irradiation, the temperature distribution of nc-YSZ surface was monitored using an infrared thermal camera. Relative luminescence unit (RLU) was used to evaluate the viability of bacteria after the NIR laser treatment.

RESULTS

Analysis of RLU suggests that the viability of E. coli biofilm formation was reduced with NIR laser treatment when compared to the control group (P < 0.01) and loss of viability depends on both laser fluence and operation mode (CW or PW). The results demonstrate that while CW laser reduces the biofilm formation more than PW laser with the same power, the higher surface temperature of the implant generated by CW laser limits its medical efficacy. In contrast, with the right parameters, PW laser produces a more moderate photothermal effect which can be equally effective at controlling bacterial growth.

CONCLUSIONS

Our results show that E. coli biofilm formation across the thickness of the nc-YSZ implant can be disrupted using NIR laser treatment. The results of this in vitro study suggest that using nc-YSZ as a cranial implant in vivo may also allow for locally selective, non-invasive, chronic treatment of bacterial layers (fouling) that might form under cranial implants, without causing adverse thermal damage to the underlying host tissue when appropriate laser parameters are used. Lasers Surg. Med. 48:782-789, 2016. © 2016 Wiley Periodicals, Inc.

Management of the temporal muscle during cranioplasty: technical note

Over the past 2 decades there has been a resurgence of interest in the use of decompressive craniectomy in the management of neurological emergencies. While technically straightforward, the procedure is associated with a number of complications relating to the initial decompression and subsequent cranioplasty. One complication that has received relatively little attention relates to the management of the temporal muscle. Here, through an illustrative case, the author describes a novel method of minimizing dissection of the temporal muscle during a cranioplasty procedure. Rather than placing a synthetic material over the dura mater to prevent adhesions or dissecting the muscle off the dura, the dura was opened and reflected laterally, pedicled to the temporal muscle. The dural defect was closed with a dural substitute, and the bone flap was secured in a routine fashion. The temporal muscle was then secured in its anatomical position. At the 6-month follow-up, radiological and clinical examination confirmed the restoration of muscle volume with excellent cosmetic and functional results. Opening the dura on a temporal muscle pedicle does not represent a routine form of surgical reconstruction; however, the use of this technique may have some advantages especially in young patients who have made a good recovery and for whom facial aesthetics may be particularly important.

Bone formation in subcutaneous pocket after bone flap preservation

Residual periosteum developed periosteal bone formation in the pocket 10 years after cranioplasty, lumpectomy was conducted on the left lower abdomen under local anesthesia. Pathological sections revealed abundant osteocytes and mature bone matrix, and confirmed the bone formation on the residual periosteum.

Computer-assisted single-stage cranioplasty

Cranioplasty treats and repairs cranial defects with a custom craniofacial implant (CCI). Typically, surgeons know the defect size prior to surgery. Recent efforts consider single-stage cranioplasty-performing the bony resection and fixating the CCI in a single operation. This paper develops a computer-assisted technique to perform single-stage cranioplasty. Intraoperatively, the surgeon traces the bony resection. The outline of the bony cuts is projected on a preoperatively-designed CCI to guide the surgeon during the resizing. A cadaveric case study showed good fit with minimal gaps between the implant and remaining skull. Moreover, the procedure reduced the time to resize the implant by an order of magnitude compared to manual resizing without the use of the computer-assisted technique. This approach represents the next step in quickly, effectively, and robustly performing single-stage CCI to treat craniofacial defects.

Preoperative external tissue expansion for complex cranial reconstructions

OBJECTIVE Reconstruction of large solitary cranial defects after multiple craniotomies is challenging because scalp contraction generally requires more than simple subcutaneous undermining to ensure effective and cosmetically appealing closure. In plastic and reconstructive surgery, soft tissue expansion is considered the gold standard for reconstructing scalp defects; however, these techniques are not well known nor are they routinely practiced among neurosurgeons. The authors here describe a simple external tissue expansion technique that is associated with low morbidity and results in high cosmetic satisfaction among patients. METHODS The authors reviewed the medical records of patients with large cranial defects (> 5 cm) following multiple complicated craniotomies who had undergone reconstructive cranioplasty with preoperative tissue expansion using the DermaClose RC device. In addition to gathering data on patient age, sex, primary pathology, number of craniotomies and/or craniectomies, history of radiation therapy, and duration of external scalp tissue expansion, the authors screened patient charts for cerebrospinal fluid (CSF) leak, meningitis, intracranial abscess formation, dermatitis, and patient satisfaction rates. RESULTS The 6 identified patients (5 female, 1 male) had an age range from 36 to 70 years. All patients had complicating factors such as recalcitrant scalp infections after multiple craniotomies or cranial radiation, which led to secondary scalp tissue scarring and retraction. All patients were deemed to be potential candidates for rotational flaps with or without skin grafts. All patients underwent the same preoperative tissue expansion followed by standard cranial bone reconstruction. None of the patients developed CSF leak, meningitis, intracranial abscess, dermatitis, or permanent cosmetic defects. None of the patients required a reoperation. Mean follow-up was 117 days. CONCLUSIONS Preoperative scalp tissue expansion with the DermaClose RC device allows for simple and reliable completion of complicated cranial reconstruction with low morbidity rates and high cosmetic satisfaction among patients.

Implant Site Infection and Bone Flap Osteomyelitis Associated with the NeuroPace Responsive Neurostimulation System

BACKGROUND

The NeuroPace RNS System is a method recently approved by the U.S. Food and Drug Administration for closed-loop direct brain stimulation in selected patients with drug-resistant partial seizures. The long-term risks of implant site infection and accompanying bone flap osteomyelitis associated with responsive neurostimulation (RNS) devices have not been fully appreciated.

CASE DESCRIPTION

We report 3 cases of refractory partial epilepsy that were treated with RNS therapy in conjunction with antiepileptic drugs. Patients underwent invasive epilepsy monitoring and resection of seizure foci. All patients continued to have debilitating partial seizures and underwent implantation of the RNS device, which resulted in various degrees of symptomatic relief. On average, the battery of the implantable pulse generator was replaced every 2 years. All 3 patients developed implant site infection and bone flap osteomyelitis with multiple implantable pulse generator replacements, and the RNS devices were removed. Bone flaps were removed in 2 patients because of significant osteomyelitis and were reconstructed in a delayed fashion with customized cranial implants. No patient had evidence of meningitis or cerebritis. The patients were treated via a multidisciplinary approach, and all patients recovered well with satisfactory wound healing and seizure control.

CONCLUSIONS

Implant site infection and bone flap osteomyelitis are significant adverse events associated with the RNS device. The incidence of infection in this series (10%) is comparable to the incidence reported in the long-term trial. The infection risk is mainly associated with reoperations and increases with multiple implantable pulse generator replacements. The RNS device may benefit from reducing technical risk factors that are associated with postoperative bone and soft tissue infections.

Cranioplasty for large-sized calvarial defects in the pediatric population: a review

Large-sized calvarial defects in pediatric patients pose a reconstructive challenge because of children's unique physiology, developing anatomy, and dynamic growth. We review the current literature and outcomes with autologous and alloplastic cranioplasty in the pediatric population.