[Topographic study of the parietal region for the elaboration of revascularized cranium vault autograft]. / Izuchenie topografo-anatomicheskikh osobennostei temennoi oblasti pri razrabotke revaskulyariziruemogo kostno-fastsial'nogo temennogo autotransplantata.

OBJECTIVE: Topographic and blood vessel architecture study of the parietal area and distal regional pool of the superficial temporal artery (STA) to assess the possibility of revascularized cranium vault bone autograft formation. MATERIAL AND METHODS: For the topographic and anatomical study, 30 non-fixed corpses (17 male and 13 female) were selected, the average age of which was 59±5 years. In the anamnesis and catamnesis, there were no indications of trauma or other pathology of the head and neck, including vascular. STA was contrasted with a non-radiocontrast dye (brilliant green) with the introduction of the dye into the STA with preliminary ligation of the frontal branch of the STA. The area of blood supply to soft tissue and bone structures was studied. The angioarchitectonics of the parietal region was studied, the feeding vessel of the studied flap was identified. RESULTS: The obtained anatomical landmarks for the collection of CPFP flap make it possible to form a flap with high accuracy and minimize the morbidity of the donor area.

Cranial Repair in Children: Techniques, Materials, and Peculiar Issues.

Cranial repair in children deserves particular attention since many issues are still controversial. Furthermore, literature data offer a confused picture of outcome of cranioplasty, in terms of results and complication rates, with studies showing inadequate follow-up and including populations that are not homogeneous by age of the patients, etiology, and size of the bone defect.Indeed, age has merged in the last years as a risk factor for resorption of autologous bone flap that is still the most frequent complication in cranial repair after decompressive craniectomy.Age-related factors play a role also when alloplastic materials are used. In fact, the implantation of alloplastic materials is limited by skull growth under 7 years of age and is contraindicated in the first years if life. Thus, the absence of an ideal material for cranioplasty is even more evident in children with a steady risk of complications through the entire life of the patient that is usually much longer than surgical follow-up.As a result, specific techniques should be adopted according to the age of the patient and etiology of the defect, aiming to repair the skull and respect its residual growth.Thus, autologous bone still represents the best option for cranial repair, though limitations exist. As an alternative, biomimetic materials should ideally warrant the possibility to overcome the limits of other inert alloplastic materials by favoring osteointegration or osteoinduction or both.On these grounds, this paper aims to offer a thorough overview of techniques, materials, and peculiar issues of cranial repair in children.

Modified Mouse Model of Repetitive Mild Traumatic Brain Injury Incorporating Thinned-Skull Window and Fluid Percussion.

Mild traumatic brain injury is a clinically highly heterogeneous neurological disorder. Highly reproducible traumatic brain injury (TBI) animal models with well-defined pathologies are urgently needed for studying the mechanisms of neuropathology after mild TBI and testing therapeutics. Replicating the entire sequelae of TBI in animal models has proven to be a challenge. Therefore, the availability of multiple animal models of TBI is necessary to account for the diverse aspects and severities seen in TBI patients. CHI is one of the most common methods for fabricating rodent models of rmTBI. However, this method is susceptible to many factors, including the impact method used, the thickness and shape of the skull bone, animal apnea, and the type of head support and immobilization utilized. The aim of this protocol is to demonstrate a combination of the thinned-skull window and fluid percussion injury (FPI) methods to produce a precise mouse model of CHI-associated rmTBI. The primary objective of this protocol is to minimize factors that could impact the accuracy and consistency of CHI and FPI modeling, including skull bone thickness, shape, and head support. By utilizing a thinned-skull window method, potential inflammation due to craniotomy and FPI is minimized, resulting in an improved mouse model that replicates the clinical features observed in patients with mild TBI. Results from behavior and histological analysis using hematoxylin and eosin (HE) staining suggest that rmTBI can lead to a cumulative injury that produces changes in both behavior and gross morphology of the brain. Overall, the modified CHI-associated rmTBI presents a useful tool for researchers to explore the underlying mechanisms that contribute to focal and diffuse pathophysiological changes in rmTBI.

A new hydroxyapatite-alginate-gelatin biocomposite favor bone regeneration in a critical-sized calvarial defect model.

This study aimed to evaluate the osteogenic potential of hydroxyapatite (HA), Alginate (Alg), and Gelatine (Gel) composite in a critical-size defect model in rats. Twenty-four male rats were divided into three groups: a negative control with no treatment (Control group), a positive control treated with deproteinized bovine bone mineral (DBBM group), and the experimental group treated with the new HA-Alg-Gel composite (HA-Alg-Gel group). A critical size defect (8.5mm) was made in the rat's calvaria, and the bone formation was evaluated by in vivo microcomputed tomography analysis (µCT) after 1, 15, 45, and 90 days. After 90 days, the animals were euthanized and histological and histomorphometric analyses were performed. A higher proportion of mineralized tissue/biomaterial was observed in the DBBM group when compared to the HA-Alg-Gel and Control groups in the µCT analysis during all analysis periods. However, no differences were observed in the mineralized tissue/biomaterial proportion observed on day 1 (immediate postoperative) in comparison to later periods of analysis in all groups. In the histomorphometric analysis, the HA-Alg-Gel and Control groups showed higher bone formation than the DBBM group. Moreover, in histological analysis, five samples of the HA-Alg-Gal group exhibited formed bone spicules adjacent to the graft granules against only two of eight samples in the DBBM group. Both graft materials ensured the maintenance of defect bone thickness, while a tissue thickness reduction was observed in the control group. In conclusion, this study demonstrated the osteoconductive potential of HA-Alg-Gel bone graft by supporting new bone formation around its particles.

Transcriptomic and cellular decoding of scaffolds-induced suture mesenchyme regeneration.

Precise orchestration of cell fate determination underlies the success of scaffold-based skeletal regeneration. Despite extensive studies on mineralized parenchymal tissue rebuilding, regenerating and maintaining undifferentiated mesenchyme within calvarial bone remain very challenging with limited advances yet. Current knowledge has evidenced the indispensability of rebuilding suture mesenchymal stem cell niches to avoid severe brain or even systematic damage. But to date, the absence of promising therapeutic biomaterials/scaffolds remains. The reason lies in the shortage of fundamental knowledge and methodological evidence to understand the cellular fate regulations of scaffolds. To address these issues, in this study, we systematically investigated the cellular fate determinations and transcriptomic mechanisms by distinct types of commonly used calvarial scaffolds. Our data elucidated the natural processes without scaffold transplantation and demonstrated how different scaffolds altered in vivo cellular responses. A feasible scaffold, polylactic acid electrospinning membrane (PLA), was next identified to precisely control mesenchymal ingrowth and self-renewal to rebuild non-osteogenic suture-like tissue at the defect center, meanwhile supporting proper osteointegration with defect bony edges. Especially, transcriptome analysis and cellular mechanisms underlying the well-orchestrated cell fate determination of PLA were deciphered. This study for the first time cellularly decoded the fate regulations of scaffolds in suture-bony composite defect healing, offering clinicians potential choices for regenerating such complicated injuries.

Extended reality in cranial and spinal neurosurgery - a bibliometric analysis.

PURPOSE: This bibliometric analysis of the top 100 cited articles on extended reality (XR) in neurosurgery aimed to reveal trends in this research field. Gender differences in authorship and global distribution of the most-cited articles were also addressed. METHODS: A Web of Science electronic database search was conducted. The top 100 most-cited articles related to the scope of this review were retrieved and analyzed for trends in publications, journal characteristics, authorship, global distribution, study design, and focus areas. After a brief description of the top 100 publications, a comparative analysis between spinal and cranial publications was performed. RESULTS: From 2005, there was a significant increase in spinal neurosurgery publications with a focus on pedicle screw placement. Most articles were original research studies, with an emphasis on augmented reality (AR). In cranial neurosurgery, there was no notable increase in publications. There was an increase in studies assessing both AR and virtual reality (VR) research, with a notable emphasis on VR compared to AR. Education, surgical skills assessment, and surgical planning were more common themes in cranial studies compared to spinal studies. Female authorship was notably low in both groups, with no significant increase over time. The USA and Canada contributed most of the publications in the research field. CONCLUSIONS: Research regarding the use of XR in neurosurgery increased significantly from 2005. Cranial research focused on VR and resident education while spinal research focused on AR and neuronavigation. Female authorship was underrepresented. North America provides most of the high-impact research in this area.

Evaluation of skull bone viability and effect of early surgical intervention in electrical contact burns using 18 F-Sodium Fluoride PET-CT imaging.

OBJECTIVE: Electrical contact burns of the scalp cause serious morbidity and mortality. Early necrotic bone debridement and flap cover are crucial for successful wound closure. 18 F Sodium Fluoride (NaF), with high bone-to-soft tissue activity ratio, is useful for bone viability assessment. This study evaluated the role of 18 F NaF PET-computed tomography (CT) in objectively defining the extent and depth of nonviable calvarial bone, to guide adequate bone debridement. METHOD: Of 20 patients referred to our institute with electrical contact burns of the scalp during a 2-year period, 15 were enrolled in the study. Two weeks after the initial management, tracer uptake pattern was noted on 18 F NaF PET-CT of the head and exposed bone measured. Surgical bone debridement was based on scan findings, followed by wound closure. All patients underwent clinical evaluation and follow-up scan 3 months after surgery. RESULTS: Eight patients showed a central photopenic area in the exposed bone (maximum standardized uptake value [SUVmax] of 0.76 ± 0.14 with mean maximum dimensions 4.10 ± 1.76/2.67 ± 1.54 cm). High tracer uptake (SUVmax, 9.66 ± 6.03) was seen peripheral to the exposed bone (mean maximum dimensions, 8.14 ± 3.03/4.75 ± 1.61 cm). Postoperatively, there was no significant change in tracer uptake in the central debrided region or peri-debridement bone area under the flap. Clinically all patients showed a well-healed flap. CONCLUSION: 18 F NaF PET-CT appears useful for objective evaluation of skull bone viability and planning necrotic bone debridement in patients with electrical contact burns. However, additional studies with longer patient follow-up are required to validate these results.

Trepanation technique.

The larger part of this chapter is concerned with the technique of drilling the cranium with a circular saw called a trepan or trephine. The terminology of the instrument is outlined. Safe use of the instrument includes probing the groove produced by its use and angling the drill so that it impinges on bone which hitherto has not been sawn through. There is then an account of how larger openings may be made by drilling multiple small holes and connecting them by means of a chisel.

Cognitive Outcomes of Children With Sagittal Craniosynostosis Treated With Either Endoscopic or Open Calvarial Vault Surgery.

Importance: Several studies have reported a higher incidence of neurodevelopmental delays and cognitive deficits in patients with single-suture craniosynostosis; however, there are few studies examining the associations of repair type with cognitive outcomes. Objective: To measure differences in neuropsychological outcomes between school-age children who were treated for sagittal craniosynostosis and unaffected controls and explore differences in cognitive function among children with sagittal craniosynostosis who were previously treated with either endoscopic strip craniectomy or open calvarial vault surgery. Design, Setting, and Participants: This cohort study was performed between 2018 and 2022. Eligible participants included patients aged 5 to 17 years who had previously been seen as infants or toddlers (<3 years) at 1 of 3 surgical centers for craniosynostosis repair with either endoscopic surgery or open calvarial vault surgery. A separate cohort of unaffected controls were included for comparison. Data analysis was conducted from November 2023 to February 2024. Exposures: Open calvarial vault surgery or endoscopic repair for single-suture craniosynostosis. Main Outcomes and Measures: The primary outcome was the Differential Ability Scales-II (DAS-II) General Conceptual Ability (GCA) score, an index for overall intellectual ability. Secondary outcomes included DAS-II subscale scores (Verbal Ability, Nonverbal Reasoning, Spatial Ability, Working Memory, and Processing Speed), and Patient-Reported Outcomes Measurement Information System (PROMIS) cognitive function scores. Results: A total of 81 patients with sagittal craniosynostosis (59 male [73%]; 22 female [27%]) and 141 controls (81 male [57%]; 60 female [43%]) were included. Of the 81 participants with sagittal craniosynostosis, 46 underwent endoscopic repair and 35 underwent open repair. Median (range) age at time of follow-up assessment was 7.7 (5.0-14.8) years for children with sagittal craniosynostosis and median age at assessment was 8.5 (7.7-10.5) years for controls. After controlling for age at assessment, sex, and socioeconomic status, there was no statistically significant or clinically meaningful difference in GCA scores between children who underwent endoscopic repair (adjusted mean score, 100; 95% CI, 96-104) and open repair (adjusted mean score, 103; 95% CI, 98-108) (P > .99). We found no significant difference in PROMIS scores between repair types (median [range] for endoscopic repair 54 [31-68] vs median [range] for open repair 50 [32-63]; P = .14). When comparing the treatment groups with the unaffected controls, differences in subscale scores for GCA and working memory were observed but were within normal range. Conclusions and Relevance: In this cohort study, there were no statistically or clinically significant differences in cognitive outcomes among school-age children by and type of surgical procedure used to repair nonsyndromic sagittal craniosynostosis. These findings suggest primary care clinicians should be educated about different options for craniosynostosis surgery to ensure early referral of these patients so that all treatment options remain viable.

[Comparison of polymethyl methacrylate skull implant fixation by three types of titanium fasteners]. / Sravnenie sposobov fiksatsii implantov cherepa iz polimetilmetakrilata tremya vidami titanovykh krepezhei.

OBJECTIVE: To evaluate mechanical strength of three methods of polymethyl methacrylate skull implant fixation in two experimental models. MATERIAL AND METHODS: The first experiment was performed on a plastic model that was as close as possible to bone in structural characteristics. The second experiment was performed on a biological specimen (a ram's head). We assessed the quality of implant fixation to bone window edges by craniofixes, ties and microscrews and lateral intercortical screws. RESULTS: Craniofixes are feasible for small flat flaps, but not advisable for wide highly curved implants. They are also the most expensive method of fixation. Implant fixation by ties and microscrews is a universal method comparable in price to craniofix. Lateral intercortical fixation is effective both for small flat implants and wide implants with large curvature. However, this method is not always applicable. CONCLUSION: Combined fixation by lateral intercortical screws and ties allows for the most effective fixation while reducing the overall price of consumables.

Injectable and In Situ Formed Dual-Network Hydrogel Reinforced by Mesoporous Silica Nanoparticles and Loaded with BMP-4 for the Closure and Repair of Skull Defects.

Bone defects are a common and challenging orthopedic problem with poor self-healing ability and long treatment cycles. The difficult-to-heal bone defects cause a significant burden of medical expenses on patients. Currently, biomaterials with mechanical stability, long-lasting action, and osteogenic activity are considered as a suitable way to effectively heal bone defects. Here, an injectable double network (DN) hydrogel prepared using physical and chemical cross-linking methods is designed. The first rigid network is constructed using methylpropenylated hyaluronic acid (HAMA), while the addition of chitosan oligosaccharide (COS) forms a second flexible network by physical cross-linking. The mesoporous silica nanoparticles (MSN) loaded with bone morphogenetic protein-4 (BMP-4) were embedded into DN hydrogel, which not only enhanced the mechanical stability of the hydrogel, but also slowly released BMP-4 to achieve long-term skull repair. The designed composite hydrogel showed an excellent compression property and deformation resistance. In vitro studies confirmed that the HAMA/COS/MSN@BMP-4 hydrogel had good biocompatibility and showed great potential in supporting proliferation and osteogenic differentiation of mouse embryo osteoblast precursor (MC3T3-E1) cells. Furthermore, in vivo studies confirmed that the DN hydrogel successfully filled and closed irregular skull defect wounds, effectively promoted bone regeneration, and significantly promoted bone repair compared with the control group. In addition, HAMA/COS/MSN@BMP-4 hydrogel precursor solution can quickly form hydrogel in situ at the wound by ultraviolet light, which can be applied to the closure and repair of wounds of different shapes, which provides the new way for the treatment of bone defects.

A reduction method for anterior opening displacement in thoracolumbarvertebral fractures with diffuse idiopathic skeletal hyperostosis using the skull clamp-assisted position.

Diffuse idiopathic skeletal hyperostosis (DISH) frequently occurs in the spine, resulting in unstable fractures. Treating thoracolumbar fractures in patients with DISH is often difficult because the anterior opening of the vertebral body is exacerbated by dislocation in the prone position, making reduction difficult. In this study, we introduced a novel skull clamp-assisted positioning (SAP) technique. The patient is placed in a supine position with a skull clamp used in cervical spine surgery before surgery to prevent the progression of dislocation and to restore the patient's position. Using this method, the mean difference in local kyphosis angle improved from -2.9 (±8.4)° preoperatively to 10.9 (±7.7)° postoperatively. Furthermore, posterior displacement decreased from a preoperative mean of 5.5 (±4.3) mm to 0.3 (±0.7) mm postoperatively. Complications such as neurological sequelae, implant fracture, and surgical site infection were not observed through one year of postoperative follow-up. SAP may decrease invasiveness and complications. Longer-term studies and larger sample sizes are needed to establish long-term efficacy and benefits.

Customised pre-operative cranioplasty to achieve maximal surgical resection of tumours with osseous involvement-a case series.

PURPOSE: Surgical resection with bony margins would be the treatment of choice for tumours with osseous involvement such as meningiomas and metastasis. By developing and designing pre-operative customised 3D modelled implants, the patient can undergo resection of meningioma and repair of bone defect in the same operation. We present a generalisable method for designing pre-operative cranioplasty in patients to repair the bone defect after the resection of tumours. MATERIALS AND METHODS: We included six patients who presented with a tumour that was associated with overlying bone involvement. They underwent placement of customised cranioplasty in the same setting. A customised implant using a pre-operative imaging was designed with a 2-cm margin to allow for any intra-operative requirements for extending the craniectomy. RESULTS: Six patients were evaluated in this case series. Four patients had meningiomas, 1 patient had metastatic breast cancer on final histology, and 1 patient was found to have an intra-osseous arteriovenous malformation. Craniectomy based on margins provided by a cutting guide was fashioned. After tumour removal and haemostasis, the cranioplasty was then placed. All patients recovered well post-operatively with satisfactory cosmetic results. No wound infection was reported in our series. CONCLUSION: Our series demonstrate the feasibility of utilising pre-designed cranioplasty for meningiomas and other tumours with osseous involvement. Following strict infection protocols, minimal intra-operative handling/modification of the implant, and close follow-up has resulted in good cosmetic outcomes with no implant-related infections.

Predicting the optimal concentration of remifentanil for skull pin fixation with hemodynamic and analgesia nociception index monitoring.

Inadequate antinociception during skull pin fixation may cause hemodynamic instability in intracranial surgery. The optimal concentration of remifentanil to provide adequate antinociception and stable hemodynamics during skull pin fixation under analgesia nociception index monitoring is unknown. This study is to assess the 90% effective concentration of remifentanil for skull pin fixation under hemodynamic and analgesia nociception index monitoring. Twenty-six patients were enrolled for intracranial surgery, anesthesia was induced and maintained under total intravenous anesthesia using target-controlled infusion for remifentanil and propofol under analgesia nociception index and bispectral index monitoring. Skull pin fixation was performed at different effect-site concentrations of remifentanil required for Dixon's up-and-down method with a step size of 0.5 ng/ml under bispectral index 40-60. Inadequate antinociception is defined when either ANI < 30 or > 20% in hemodynamic changes from baseline (e.g. heart rate > 100 beats/min, or blood pressure > 180/100 mmHg) and the effect-site concentration of remifentanil is considered as failure. It is considered success as ANI > 30 and < 20% hemodynamic changes from baseline simultaneously. Seven pairs of failure/success were used for probit analysis. The 90% effective concentration of remifentanil for skull pin fixation with adequate antinociception and hemodynamic stability was 4.7 ng/ml.

Letter to editor: Exploring complications following cranioplasty after decompressive hemicraniectomy: A retrospective bicenter assessment of autologous, PMMA and CAD implants.

This study presents a critical analysis of complications following cranioplasty (CP) after decompressive hemicraniectomy, focusing on autologous, polymethylmethacrylate (PMMA), and computer-aided design (CAD) implants. The analysis encompasses a retrospective bicenter assessment, evaluating factors influencing surgical outcomes and emphasizing the significance of material selection in minimizing postoperative complications. The study's comprehensive examination of complication rates associated with various implant materials contributes significantly to understanding CP outcomes. While polymethylmethacrylate (PMMA) and autologous bone flaps (ABFs) exhibited higher rates of surgical site infection (SSI) and explantation, a meta-analysis revealed a contrasting lower infection rate for polyether ether ketone (PEEK) implants. The study underscores the critical role of material selection in mitigating postoperative complications. Despite its strengths, the study's retrospective design, reliance on data from two centers, and limited sample size pose limitations. Future research should prioritize prospective, multicenter studies with standardized protocols to enhance diagnostic accuracy and treatment efficacy in CP procedures.

Subcutaneous preservation versus cryopreservation of autologous bone grafts for cranioplasty: A systematic review and meta-analysis.

BACKGROUND: Cranioplasty corrects cranial bone defects using various bone substitutes or autologous bone flaps created during a previous craniectomy surgery. These autologous bone flaps can be preserved through subcutaneous preservation (SP) or cryopreservation (CP). AIM: We aim to compare outcomes and complications for both SP and CP techniques to enhance the current evidence about autologous bone flap preservation. METHODS: Five electronic databases were searched to collect all relevant studies. Records were screened for eligibility. Data were extracted from the included studies independently. We categorized surgical site infection (SSI) as either due to Traumatic brain injury (TBI) or not to reveal potential variations in SSI incidence. The double-arm meta-analysis utilized risk ratios (RR) and mean differences (MD) with corresponding confidence intervals (CI) to pool categorical and continuous outcomes, respectively. Proportions with their respective 95% CIs were pooled for single-arm meta-analyses to determine outcomes related to SP technique. RESULTS: Seventeen studies involving 1169 patients were analyzed. No significant difference in SSI rates was observed between SP and CP methods in patients with or without TBI. SP was linked to shorter hospital stays in two studies (194 patients). Single-arm analysis showed a 17% revision surgery rate across five studies (375 patients) and infection rates in 17 studies for SP. New bone formation occurred in 13.2% of patients, with 19.9% showing resorption. CONCLUSION: SP and CP methods showed similar SSI rates post-craniectomy in TBI and non-TBI patients. SP was associated with reduced hospitalization time, low infection rates, and a moderate need for revision surgery.