Immediate Single-Stage Cranioplasty Following Calvarial Resection for Benign and Malignant Skull Neoplasms Using Customized Craniofacial Implants

Neuroplastic Surgery Principles of Computerized Surgical Planning in Complex Cranioplasty Reconstruction

This article explores the evolution and implementation of three-dimensional (3D) models and Computerized Surgical Planning (CSP) for complex cranioplasty reconstruction and the advances in neuroplastic surgery principles for improved surgical outcomes. Over recent years, CSP has revolutionized the field by employing detailed medical imaging to enhance the accuracy and efficacy of 3D models and for the creation of customized cranial implants (CCIs). The study discusses the advancements of solid alloplastic implants to the future of implants with sophisticated and integrated neurotechnology to treat or enhance patient outcomes. CSP can be used to identify and mitigate complications that can occur within cranioplasty reconstruction and to create CCIs to address the postoperative challenge of temporal hollowing. Despite the promising advancements, the article acknowledges the current limitations of CSP, including cost and technological accessibility, and proposes future directions for research and development. The findings suggest that with further improvements in imaging, biomaterials, and manufacturing techniques, CSP in neuroplastic surgery and other specialties will continue to significantly enhance the precision and personalized care of cranioplasty reconstruction.

Current Concepts in Cranial Reconstruction: Review of Alloplastic Materials

Cranioplasty for acquired cranial defects can be complex and challenging. Benefits include improved cosmesis, protection of intracranial structures, and restoration of neurocognitive function. These defects can be reconstructed with preserved craniectomy bone flaps, split autografts, or alloplastic materials. When alloplastic cranioplasty is planned, the material should be carefully selected. There is confusion on which material should be used in certain scenarios, particularly in composite defects.

The Multiple Rib Osteomyocutaneous Split Latissimus Dorsi Flap for Calvarial Reconstruction: Indication, Operative Technique, and Review of Literature

Major complex cranial defects may be challenging for the reconstructive microsurgeon. Affected patients often present with impaired soft tissues including dura exposure or fistulas. The lacking structural bony support may cause severe neurological issues and in select patients, there is a need for well-vascularized autologous tissue repair. The authors herein elucidate the role of the multiple rib osteomyocutaneous split latissimus dorsi flap for reconstruction of composite skull defects, providing an indication, an exemplary case, operation technique, and literature review. A 40-year-old woman after anaplastic oligodendroglioma resection suffered multiple extrusions and allograft cranioplasty infections. The defect was reconstructed with an osteomyocutaneus split latissimus dorsi flap including costae 3 ribs and a skin island. The included ribs were nourished via the anterior periosteum, while the posterior periosteum was left in place for the protection of the pleura parietalis. A proper amount of craniomedial latissimus dorsi muscle was spared to reduce donor site morbidity. The patient presented after 6 months with stable bony and soft tissue conditions without neurological symptoms, and acceptable donor site morbidity. After failed alloplastic cranioplasties, the free latissimus dorsi flap including vascularized ribs is well suitable for coverage of large compound cranial defects, providing skeletal support, improved contour, and enhanced functional outcome.

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.

Characterisation of Selected Materials in Medical Applications

Tissue engineering is an interdisciplinary field of science that has developed very intensively in recent years. The first part of this review describes materials with medical and dental applications from the following groups: metals, polymers, ceramics, and composites. Both positive and negative sides of their application are presented from the point of view of medical application and mechanical properties. A variety of techniques for the manufacture of biomedical components are presented in this review. The main focus of this work is on additive manufacturing and 3D printing, as these modern techniques have been evaluated to be the best methods for the manufacture of medical and dental devices. The second part presents devices for skull bone reconstruction. The materials from which they are made and the possibilities offered by 3D printing in this field are also described. The last part concerns dental transitional implants (scaffolds) for guided bone regeneration, focusing on polylactide-hydroxyapatite nanocomposite due to its unique properties. This section summarises the current knowledge of scaffolds, focusing on the material, mechanical and biological requirements, the effects of these devices on the human body, and their great potential for applications.

Reconstruction of Cranial Bone Defects Using Polyamide 12 Patient-Specific Implant: Long Term Follow Up

ABSTRACT

The main objective of this study was to evaluate the use of patient-specific polyamide 12 implants in cranial bone defect reconstruction.Ten patients who underwent prior decompression craniectomy were selected for the current study. Skull scanning by computerized tomography was performed and used to make virtual planning of the implants to be transformed into physical implant using selective laser sintering. Cranioplasty was performed through coronal surgical approach where cranial implants were fixated using 2.0-mm mini-screws, and plates. Patients follow-up was from 12 to 36 months. Glasgow Outcome Score recorded 1 (good recovery) for all patients. Patient and surgeon satisfaction for the esthetic outcome were measured using visual analog scale as mean of 10 ± 0 and 9 ± 1, respectively. Cranial symmetry index was calculated as mean score of 98% ± 1%, indicating highly accurate symmetry, and preoperative virtual planning and postoperative outcome were compared for accuracy analysis with a mean difference of 0.3197 ± 0.1649, which indicates high accuracy.Polyamide12 cranial implants seem to offer a promising option to cranial bone reconstruction with patient-specific implants. This study ensures proper cosmetic and clinical outcome.

A Good Aesthetic Outcome After Gross Total Tumor Resection in Combination With the Skull Reconstruction on Giant Epidermal Cyst Involving Both Intracranial and Extracranial Tissues

ABSTRACT

Epidermal or epidermoid cysts are 1 of the most frequent benign masses, they rarely grow to a huge size, and only a few cases have been reported. We report a rare case of a 52-year-old man with giant neoplasm growing invasively in the frontal region, including both intracranial and extracranial extensions, and caused extensive brain deformation and skull lesions. It is worth noting that the patient did not present any significant neurological symptoms and deficits for more than 40 years on admission. A combination of gross total tumor resection and cranioplasty was performed. The patient was satisfied with the results of the surgery, and no evidence of recurrence or complications were found in the 2 years follow-up. The authors reported the case not only to propose the first-stage aesthetic treatment option for this unusual mass on the scalp but also hinted at the vigilance and importance of systematic monitoring of the small skull mass for avoiding the potential risk of tumor progression, malignant transformation, operative trauma, and financial burden.

Case Report: Simultaneous Resection of Bone Tumor and CAD/CAM Titanium Cranioplasty in Fronto-Orbital Region

Background: Simultaneous resection of bone tumors in the fronto-naso-orbital region is a great challenge due to the need for adequate reconstruction of the facial skeleton. Pre-operative virtual planning of resection margins and the simultaneous fabrication of the cranioplasty using computer-aided design/computer-aided manufacturing (CAD/CAM) technology could allow combining the tumor resection and cosmetic restoration steps into a single procedure.

Methods: We present five consecutive cases of patients with bone tumors of the fronto-naso-orbital region. The indications for surgery included: (1) the presence of a major cosmetic defect; (2) progressive tumor growth. The histological examination revealed vascular malformation, hemangioma, and fibrous dysplasia in two cases. Tumor resection was performed with the help of a drilling template in form of a tumor. The computer-designed cranioplasty formed based on the non-involved side of the skull of the patient was manufactured. In one patient, the reconstruction was performed using two separate implants.

Results: The position of the implant fits in with pre-operative planning in two cases; in those cases, the additional trimming of the implant or bone defect was required. Good cosmetic outcomes were noted in all patients, and no complications occurred. No repeat surgery was necessary. The template has proved to have high application potential.

Conclusion: Simultaneous resection and CAD/CAM cranioplasty in the case of bone tumors in the fronto-orbital region is a promising technique with the aim of minimizing operation time and achieving a good esthetic outcome.

Surgical Treatment of Recurrent Spheno-Orbital Meningioma

OBJECTIVE

The extensive bone infiltration and carpet-like growth characteristics of spheno-orbital meningioma (SOM) make it hard to remove entirely, and recurrence and proptosis are the main reasons for reoperation. The authors report 20 cases of surgical treatment for recurrence of SOM, including surgical technique and symptom improvement.

METHODS

The clinical data and follow-up results of 20 cases of recurrent SOM at our institution from 2000 to 2017 were retrospectively analyzed.

RESULTS

All of the 20 patients with recurrence had received at least one operation before admission, with a mean age of 56 years and 70% female. The mean follow-up time was 36 months (1-72 months). All patients mainly showed symptoms such as proptosis and headache, and were found to be affected by supraorbital fissure during the operation. In 17 patients with recurrence, the affected sphenoid wing became tumor-like hyperplasia. Patients with extraocular muscle involvement have obvious protrusion and are often accompanied by diplopia. After surgical removal of the tumor, the symptoms of proptosis in 19 patients were significantly improved. During the follow-up, only 3 cases of proptosis recurred. After 15 patients underwent Simpson grade IV resection, 4 patients (27%) relapsed again. Five patients underwent Simpson III resection, and only 1 patient (20%) had tumor recurrence 18th months after surgery, and no proptosis recurred.

CONCLUSIONS

The complete surgical removal of recurrent SOM is practically impossible. The main direction of surgical treatment should be to improve the symptoms of proptosis.

Automated Implant Resizing for Single-Stage Cranioplasty

Patient-specific customized cranial implants (CCIs) are designed to fill the bony voids in the cranial and craniofacial skeleton. The current clinical approach during single-stage cranioplasty involves a surgeon modifying an oversized CCI to fit a patient's skull defect. The manual process, however, can be imprecise and time-consuming. This paper presents an automated surgical workflow with a robotic workstation for intraoperative CCI modification that provides higher resizing accuracy compared to the manual approach. We proposed a 2-scan method for intraoperative patient-to-CT registration using reattachable fiducial markers to address the registration issue caused by the clinical draping requirement. First, the draped defected skull was 3D scanned and registered to the CT space using our proposed 2-scan registration method. Next, our algorithm generates a robot cutting toolpath based on the 3D defect model. The robot then performs automatic 3D scanning to localize the implant and resizes the implant to match the cranial defect. We evaluated the implant resizing accuracy of the proposed paradigm against the resizing accuracy of the manual approach by an expert surgeon on two plastic skulls and two cadavers. The evaluation results showed that our system was able to decrease the bone gap distance by more than 60% and 30% on plastic skulls and cadavers respectively compared to the manual approach, indicating lower risk of post-surgical complication and better aesthetic restoration.

Virtual Surgical Planning for Intracranial Intraosseous Meningioma Reconstruction

OBJECTIVE

To assess the use of custom-made intracranial implants and three-dimensional cutting guides to direct the intracranial, intraorbital, and temporal reconstruction process for intraosseous meningioma.

METHODS

A retrospective analysis was conducted on 6 patients who were operated on by the senior author for intraosseous meningioma between 2017 and 2020. Three-dimensional models of the maxillofacial skeleton were created from preoperative virtual planned reconstruction and postoperative computed tomography scan images in the Mimics and 3-Matics software. Orbital reconstruction and temporal implant accuracy assessments were performed through the Materialise Mimics software.

RESULTS

Orbital cone volume had a mean discrepancy between the planned and actual orbital volume of 1.5% ± 1.6%. The reconstructed postoperative orbital volume was within 1.3% ± 2.0% of the unaffected orbit. Temporal bone reconstructions had a mean implant accuracy of 81.0%.

CONCLUSIONS

Our results show that the postextirpative intracranial applications of virtual surgical planning are particularly suited for high fidelity reconstructions such as orbital reconstructions, as well as temporal reconstructions with intraoperative adjustments. Custom implants and virtual three-dimensional planning is particularly ideal and promising for intraosseous meningiomas given the involvement of complex intracranial and intraorbital bony structures.

Translucent Customized Cranial Implants Made of Clear Polymethylmethacrylate: An Early Outcome Analysis of 55 Consecutive Cranioplasty Cases

BACKGROUND

Large skull reconstruction, with the use of customized cranial implants, restores cerebral protection, physiologic homeostasis, and one's preoperative appearance. Cranial implants may be composed of either bone or a myriad of alloplastic biomaterials. Recently, patient-specific cranial implants have been fabricated using clear polymethylmethacrylate (PMMA), a visually transparent and sonolucent variant of standard opaque PMMA. Given the new enhanced diagnostic and therapeutic applications of clear PMMA, we present here a study evaluating all outcomes and complications in a consecutive patient series.

METHODS

A single-surgeon, retrospective, 3-year study was conducted on all consecutive patients undergoing large cranioplasty with clear PMMA implants (2016-2019). Patients who received clear PMMA implants with embedded neurotechnologies were excluded due to confounding variables. All outcomes were analyzed in detail and compared with previous studies utilizing similar alloplastic implant materials.

RESULTS

Fifty-five patients underwent cranioplasty with customized clear PMMA implants. Twenty-one (38%) were performed using a single-stage cranioplasty method (ie, craniectomy and cranioplasty performed during the same operation utilizing a prefabricated, oversized design and labor-intense, manual modification), whereas the remaining 34 (62%) underwent a standard, 2-stage reconstruction (craniectomy with a delayed surgery for cranioplasty and minimal-to-no implant modification necessary). The mean cranial defect size was 101.8 cm. The mean follow-up time was 9 months (range, 1.5-39). Major complications requiring additional surgery occurred in 7 patients (13%) consisting of 2 (4%) cerebrospinal fluid leaks, 2 (4%) epidural hematomas, and 3 (4%) infections. In addition, 3 patients developed self-limiting or nonoperative complications including 2 (4%) with new onset seizures and 1 (2%) with delayed scalp healing.

CONCLUSIONS

This is the first reported consecutive case series of cranioplasty reconstruction using customized clear PMMA implants, demonstrating excellent results with regard to ease of use, safety, and complication rates well below published rates when compared with other alloplastic materials. Clear PMMA also provides additional benefits, such as visual transparency and sonolucency, which is material specific and unavailable with autologous bone. Although these early results are promising, further studies with multicenter investigations are well justified to evaluate long-term outcomes.

Extensive Polyostotic Craniofacial Fibrous Dysplasia With Optic Nerve Impingement

ABSTRACT

Fibrous dysplasia is a benign overgrowth of metaplastic fibrous material resulting in disorganized deposition of bony matrix. Surgical intervention is the primary treatment modality. Here the authors present the case of a 36-year-old male with extensive and severe fibrous dysplasia of the calvarium, orbit, sphenoid, and facial bones causing significant facial distortion and impingement of his optic nerve. Combined operative treatment with craniofacial plastic surgery and neurosurgery was performed. Repair consisted of extensive intra- and extracranial resection and contouring of involved bones followed by reconstruction of the superior orbital rims, forehead, orbital roof, and calvarium with custom polyetheretherketone (PEEK) implant. The authors discuss the advantages of using computer assisted design/modeling, intraoperative neuronavigation, and custom prosthetic cranioplasty for surgical treatment of extensive fibrous dysplasia; a review of the current surgical literature is provided.

Modified Cranioplasty and Latissimus Dorsi Flap for an Exophytic Invasive Brain Tumor

ABSTRACT

We describe the clinical case of a 62-year-old man with an atypical grade II meningioma, invading bone and scalp, and present a step-by-step video description of a modified technique for cranioplasty and scalp reconstruction with latissimus dorsi flap. By using this technique, we aim to minimize the space between the dura and the flap, which would decrease the risk of fluid collections and infections.

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.

Feasibility of customizing titanium implant with three-dimensional CT imaging of low dose in skull

OBJECT

To explore the feasibility and practicability of making virtual three-dimensional model of skull defect and customizing titanium implant by skull three-dimensional CT examination of low dose.

METHODS

Sixty patients with skull defects who underwent skull three-dimensional CT before cranioplasty were randomly divided into 4 groups: group A (conventional dose 120 peak Kilovoltage (kVp), 150 tube current time product (mAs)), low dose group B (120 kVp, 50 mAs), low dose group C (100 kVp, 50 mAs), low dose group D (100 kVp, 30 mAs). After the scanning, we compared radiation doses and image quality among the groups. The CT data were sent to the reconstruction company to produce accurate titanium implants, and neurosurgeons performed cranioplasty. After the operation, patients immediately underwent head CT scans to confirm the accuracy of the implantation position, and a series of clinical functions were evaluated.

RESULTS

There were significant differences in dose length product (DLP) and effective dose (ED) among the 4 groups (P < .001). The volume CT dose index (CDTIvol), DLP, and ED in group D were, respectively, 87.1%, 86.9%, and 87.3% lower than those in group A (P < .001). All images quality were at or above the general level, and there was no statistical difference (P > .05). Titanium implants were successfully manufactured, every cranioplasty was carried out smoothly, and the clinical function of patients recovered well.

CONCLUSION

Customizing titanium implant with three-dimensional CT imaging of low dose in skull not only met the clinical requirements, but also significantly reduced the radiation dose and hazard.

Presentation and short-term evaluation of an all-in-one patient-specific implant for cranial reconstruction: A randomized controlled trial

Cranial reconstruction after bone graft harvesting remains a challenge. A patient-specific implant (PSI) to guide harvesting and reconstruction was evaluated and compared with the use of a free-hand procedure with calcium phosphate cement (C). Patients were randomized to either the PSI or C group. The outcome was measured clinically and radiographically as the primary endpoint. Secondary endpoints were ease of application, patient and surgeon satisfaction, and the complication rate. Twenty patients were randomized to the PSI (n=10) and C (n=10) groups. Two PSI patients were switched to the cement group due to a poor fit of the PSI. There was a non-significant trend towards more successful outcomes in the PSI group. Two PSI patients presented palpable screws, and one cement patient had a palpable dimple. Cone beam computed tomography showed a significantly lower median volume discrepancy in the PSI group (P<0.0001). The total surgical manipulation time was significantly higher in the PSI group. At 10 days postoperative, three PSI and two C patients presented with minor postoperative complications. There was no significant difference in patient or surgeon satisfaction. PSIs are a reliable alternative to cement. This PSI is novel as it also serves as a guide for harvesting the bone blocks required for reconstructive purposes.

Handmade Cranioplasty: An Obsolete Procedure or a Surgery That Is Still Useful?

Custom made cranioplasty (CM CPL) represents the gold standard for cranial defect reconstruction, allowing an adequate protection of the brain with good cosmetic results. Nevertheless, it is an expensive procedure, requiring time for preparation of the prothesis. Aim of this study is to evaluate whether and in what cases handmade cranioplasty (HM CPL) still represents a valid alternative to CM CPL.Therefore, all consecutive cranioplasties in our center from 2013 to 2019 have been analyzed. Size and location of cranial defect have been considered, as the cause of decompression. Morbidity rate and final outcome have been evaluated. Series includes 143 patients (61% males, mean age: 60 years, SD:16). HM CPL was performed in 59 cases (41.2%) and CM in the remaining 84 (58.8%). HM CPL was preferred for smaller cranial defects (p: 0.22), inferior to 100 cm (p: 0.01) located in fronto-parietal-occipital area (p: 0.01). Furthermore, HM CPL results in the first choice after removal of infiltrative tumors (p: 0.02). Surgical complications consisted in 14 (9%) infections, 8 hematomas (5.6%), and one cranioplasty displacement (0.7%). At follow-up, in 85.3% of cases the CPL is still in place with satisfactory cosmetic and functional outcome (86.5% of HM CPL, 84.5% of CM CPL).HM CPL may still represent an effective and economic alternative procedure, when specific patient selection criteria are respected. This technique requires a long learning learning curve and demanding surgical maneuvers. Our handmade reconstruction technique with some hints to improve the esthetic result is presented.

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.

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.

Complex Scalp and Calvarium Defects After Giant Basal Cell Carcinoma Excision: Management, Challanges, Outcomes

Giant basal cell carcinoma (GBCC) is defined as a tumor ≥5 cm in diameter. GBCC of scalp usually requires extended resection of soft tissues, calvarium, and dura. In this study, we present 5 patients with GBCC of head, who underwent a single-stage combined scalp, calvarium, and dural reconstruction. Herein, we aim to discuss reconstruction methods, cerebrospinal fluid (CSF) leakage, duration of hospital stay, and tumor recurrency. Peroperative and postoperative follow-ups, defect areas, and performed calvarium reconstruction methods of 5 patients, who underwent complex scalp and calvarium reconstruction after GBCC between year 2010 and 2017, were retrospectively maintained. We studied reconstruction methods, CSF leakage, duration of hospital stay, and tumor recurrency. All patients undergone single-stage reconstruction. Avarge duration of hospital stay was 15 days. Titanium mesh was used in 3 patients and methyl methacrylate was used in 2 patients for calvarium reconstruction. CSF leakage was seen in patients who underwent calvarium reconstruction with titanium mesh. Tumor recurrence occured next to calvarium in 1 patient who undergone calvarium reconstruction with methyl methacrylate. CSF leakage and duration of hospital stay may induce morbidity of this oncoplastic procedure. The fact of longer hospital stay of patients reconstructed with titanium mesh might be a new data presented in this study. These parameters can be related with the method of calvarium reconstruction.

Classification of the Residual Cranial Defects and Selection of Reconstruction Materials

The cranial defects are complex in nature and are due to various causes. Therefore, there is a need for a common term of reference to these defects. This requirement stood as a prime reason for proposing a classification system for cranial defects. The classification is based on 2 decades of experience in cranioplasty. This efficient and simple way of representation would fill the existing lacunae for a systematic communication on cranial defects. Over the ages the evolution of reconstruction and grafting had undergone a massive progress. Therefore, it is essential to enumerate all available graft and bio-materials for restoring the cranial defects. The aetiology for these defects, age and sex of the patient, site and size of the defect, associated systemic conditions, cost factor, and operator's choice are the factors that play key role in the selection of the reconstructive material. This article discusses on these factors in cranioplasty. High success rate with excellent function and cosmetic outcome in using a variety of materials, as shared in this article. The advantages of autografts cannot be matched by any existing alloplast. However, in case of larger defects, for a better cosmetic outcome and to reduce the donor site morbidity, alloplasts are the most widely preferred material of choice.

First In-Human Experience With Complete Integration of Neuromodulation Device Within a Customized Cranial Implant

BACKGROUND

Neuromodulation devices have the potential to transform modern day treatments for patients with medicine-resistant neurological disease. For instance, the NeuroPace System (NeuroPace Inc, Mountain View, California) is a Food and Drug Administration (FDA)-approved device developed for closed-loop direct brain neurostimulation in the setting of drug-resistant focal epilepsy. However, current methods require placement either above or below the skull in nonanatomic locations. This type of positioning has several drawbacks including visible deformities and scalp pressure from underneath leading to eventual wound healing difficulties, micromotion of hardware with infection, and extrusion leading to premature explantation.

OBJECTIVE

To introduce complete integration of a neuromodulation device within a customized cranial implant for biocompatibility optimization and prevention of visible deformity.

METHODS

We report a patient with drug-resistant focal epilepsy despite previous seizure surgery and maximized medical therapy. Preoperative imaging demonstrated severe resorption of previous bone flap causing deformity and risk for injury. She underwent successful responsive neurostimulation device implantation via complete integration within a clear customized cranial implant.

RESULTS

The patient has recovered well without complication and has been followed closely for 180 d. Device interrogation with electrocorticographic data transmission has been successfully performed through the clear implant material for the first time with no evidence of any wireless transmission interference.

CONCLUSION

Cranial contour irregularities, implant site infection, and bone flap resorption/osteomyelitis are adverse events associated with implantable neurotechnology. This method represents a novel strategy to incorporate all future neuromodulation devices within the confines of a low-profile, computer-designed cranial implant and the newfound potential to eliminate contour irregularities, improve outcomes, and optimize patient satisfaction.

Usefulness of an Osteotomy Template for Skull Tumorectomy and Simultaneous Skull Reconstruction

BACKGROUND

Simultaneous tumor resection and cranioplasty with hydroxyapatite osteosynthesis are sometimes necessary in patients of skull neoplasms or skull-invasive tumors. However, the disadvantage of simultaneous surgery is that mismatches often occur between the skull defect and the hydroxyapatite implant. To solve this problem, the authors developed a customized template for designing the craniotomy line.

METHODS

Before each operation, the craniotomy design was discussed with a neurosurgeon. Based on the discussion, 2 hydroxyapatite implants were customized for each patient on the basis of models prepared using computed tomography data. The first implant was an onlay template for the preoperative cranium, which was customized for designing the osteotomy line. The other implant was used for the skull defect. Using the template, the osteotomy line was drawn along the template edge, osteotomy was performed along this line, and the implant was placed in the skull defect.

RESULTS

This technique was performed in 3 patients. No implant or defect trimming was required in any patient, good cosmetic outcomes were noted in all patients, and no complications occurred.

CONCLUSION

Use of predesigned hydroxyapatite templates for craniotomy during simultaneous skull tumor resection and cranioplasty has some clinical advantages: the precise craniotomy line can be designed, the implant and skull defect fit better and show effective osteoconduction, trimming of the implant or defect is minimized, and the operation time is shortened.

A Craniomaxillofacial Surgical Assistance Workstation for Enhanced Single-Stage Reconstruction Using Patient-Specific Implants

BACKGROUND

Craniomaxillofacial reconstruction with patient-specific, customized craniofacial implants (CCIs) is ideal for skeletal defects involving areas of aesthetic concern-the non-weight-bearing facial skeleton, temporal skull, and/or frontal-forehead region. Results to date are superior to a variety of "off-the-shelf" materials, but require a protocol computed tomography scan and preexisting defect for computer-assisted design/computer-assisted manufacturing of the CCI. The authors developed a craniomaxillofacial surgical assistance workstation to address these challenges and intraoperatively guide CCI modification for an unknown defect size/shape.

METHODS

First, the surgeon designed an oversized CCI based on his/her surgical plan. Intraoperatively, the surgeon resected the bone and digitized the resection using a navigation pointer. Next, a projector displayed the limits of the craniofacial bone defect onto the prefabricated, oversized CCI for the size modification process; the surgeon followed the projected trace to modify the implant. A cadaveric study compared the standard technique (n = 1) to the experimental technique (n = 5) using surgical time and implant fit.

RESULTS

The technology reduced the time and effort needed to resize the oversized CCI by an order of magnitude as compared with the standard manual resizing process. Implant fit was consistently better for the computer-assisted case compared with the control by at least 30%, requiring only 5.17 minutes in the computer-assisted cases compared with 35 minutes for the control.

CONCLUSION

This approach demonstrated improvement in surgical time and accuracy of CCI-based craniomaxillofacial reconstruction compared with previously reported methods. The craniomaxillofacial surgical assistance workstation will provide craniofacial surgeons a computer-assisted technology for effective and efficient single-stage reconstruction when exact craniofacial bone defect sizes are unknown.

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.

In Situ Cranioplasty Technique for Immediate Calvarial Reconstruction to Optimize Cosmesis

OBJECTIVE

One of the goals of calvarial reconstruction after craniectomy is optimization of cosmesis. A simple technique for intraoperative generation of an implant based on the patient's native skull contour for immediate skull reconstruction after craniectomy is described.

METHODS

In this technique, a titanium mesh is molded to the contour of the skull in situ and temporarily secured to the calvarium before the craniectomy. After the definitive portion of the procedure, the implant is resecured using the predrilled holes in the skull.

RESULTS

In situ titanium cranioplasties are easily contoured to the patient's native skull before, and resecured after, craniectomy. Postoperative cosmesis is excellent.

CONCLUSIONS

In selected cases, this technique for in situ cranioplasty before craniectomy generates an implant that mimics the patient's calvarium and results in excellent cosmetic outcomes.

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.