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.

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.

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

Cranioplasty (CP) after decompressive hemicraniectomy (DHC) is a common neurosurgical procedure with a high complication rate. The best material for the repair of large cranial defects is unclear. The aim of this study was to evaluate different implant materials regarding surgery related complications after CP. Type of materials include the autologous bone flap (ABF), polymethylmethacrylate (PMMA), calcium phosphate reinforced with titanium mesh (CaP-Ti), polyetheretherketone (PEEK) and hydroxyapatite (HA). A retrospective, descriptive, observational bicenter study was performed, medical data of all patients who underwent CP after DHC between January 1st, 2016 and December 31st, 2022 were analyzed. Follow-up was until December 31st, 2023. 139 consecutive patients with a median age of 54 years who received either PMMA (56/139; 40.3%), PEEK (35/139; 25.2%), CaP-Ti (21/139; 15.1%), ABF (25/139; 18.0%) or HA (2/139; 1.4%) cranial implant after DHC were included in the study. Median time from DHC to CP was 117 days and median follow-up period was 43 months. Surgical site infection was the most frequent surgery-related complication (13.7%; 19/139). PEEK implants were mostly affected (28.6%; 10/35), followed by ABF (20%; 5/25), CaP-Ti implants (9.5%; 2/21) and PMMA implants (1.7%, 1/56). Explantation was necessary for 9 PEEK implants (25.7%; 9/35), 6 ABFs (24.0%; 6/25), 3 CaP-Ti implants (14.3%; 3/21) and 4 PMMA implants (7.1%; 4/56). Besides infection, a postoperative hematoma was the most common cause. Median surgical time was 106 min, neither longer surgical time nor use of anticoagulation were significantly related to higher infection rates (p = 0.547; p = 0.152 respectively). Ventriculoperitoneal shunt implantation prior to CP was noted in 33.8% (47/139) and not significantly associated with surgical related complications. Perioperative lumbar drainage, due to bulging brain, inserted in 38 patients (27.3%; 38/139) before surgery was protective when it comes to explantation of the implant (p = 0.035). Based on our results, CP is still related to a relatively high number of infections and further complications. Implant material seems to have a high effect on postoperative infections, since surgical time, anticoagulation therapy and hydrocephalus did not show a statistically significant effect on postoperative complications in this study. PEEK implants and ABFs seem to possess higher risk of postoperative infection. More biocompatible implants such as CaP-Ti might be beneficial. Further, prospective studies are necessary to answer this question.

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.

Cryopreserved bone flaps from decompressive craniectomies: a microbiological analysis.

PURPOSE: Surgical site infection (SSI) is a serious complication after cranioplasty. Due to the relatively frequent occurrence of post-cranioplasty SSI, the utility of autologous bone flap swab cultures surrounding cryopreservation as a reliable predictor has been the subject of an ongoing debate. This bicentric study aims to contribute to this topic by conducting an in-depth analysis of bone flaps obtained via decompressive craniectomies. This study had three major aims: assessments of 1) bacterial contamination of bone flaps after decompressive craniotomy, 2) impact of cryoconservation on contamination rates and 3) potential effectiveness of anti-infective treatment to reduce the germ load prior to cranioplasty. METHODS: Cryopreserved bone flaps from two centers were used. Microbiological cultivations of swabs prior to and after cryopreservation were taken and assessed for aerobic and anaerobic growth over a 14-day incubation period. Additionally, in a subset of bone flaps, swab testing was repeated after thorough rinsing with an anti-infectant (octenidine-phenoxyethanol) followed by saline. RESULTS: All 63 bone flaps (patients median age at surgery: 59 years) were obtained via decompressive craniectomies. Swabs done prior to cryopreservation revealed a 54% infection rate with Propionibacterium acnes being the most common microorganism in 65% of those cases. After thorough disinfection of the preserved bone flaps, all but one case showed no bacterial growth in swab testing. Furthermore, no relevant risk factors for bacterial contamination could be identified. CONCLUSION: This retrospective study showed the common presence of bacterial growth in cryopreserved bone flaps before and after freezing. Rinsing with octenidine-phenoxyethanol and saline effectively prevented bacterial growth in a notable percentage of cases, suggesting a potential strategy to reduce contamination. However, persistent bacterial growth in some cases underscores the need for further research to optimize antiseptic measures during autologous cranioplasty.

How I do it: single-staged emergency neurosurgical management of frontal penetrating craniocerebral injury with depressed skull fracture.

CONTEXT: Penetrating craniocerebral injury associated with depressed skull fracture is an infrequent yet timely neurosurgical emergency. Such injury frequently occurs in the frontal region during traffic accident or stone throw in the civilian setting. As military neurosurgeons, we present our experience in the surgical debridement and reconstruction of this peculiar type of traumatic brain injury. METHODS: The patient lies supine, the head in neutral position heal by a Mayfield head clamp. The first step is the debridement of the frontal wound. Then, the depressed skull fracture is operated on using a tailored coronal approach through Merkel dissection plane, in order to keep a free pericranial flap. The bone flap is cut around the depressed skull fracture. Neuronavigation allows to locate the frontal sinus depending on whether it has been breached and thus requires cranialization. Brain and dura mater debridement and plasty are performed. Cranioplasty is performed using either native bone fragments fixed with bone plates or tailored titanium plate if they are too damaged. CONCLUSION: Performing wounded skin closure first and then a tailored coronal approach with free pericranial flap and a craniotomy encompassing the depressed skull fracture allows to treat frontal penetrating craniocerebral injury in an easy-to-reproduce manner.

Assessment of cranial reconstruction utilizing various implant materials: finite element study.

The human head can sometimes experience impact loads that result in skull fractures or other injuries, leading to the need for a craniectomy. Cranioplasty is a procedure that involves replacing the removed portion with either autologous bone or alloplastic material. While titanium has traditionally been the preferred material for cranial implants due to its excellent properties and biocompatibility, its limitations have prompted the search for alternative materials. This research aimed to explore alternative materials to titanium for cranial implants in order to address the limitations of titanium implants and improve the performance of the cranioplasty process. A 3D model of a defective skull was reconstructed with a cranial implant, and the implant was simulated using various stiff and soft materials (such as alumina, zirconia, hydroxyapatite, zirconia-reinforced PMMA, and PMMA) as alternatives to titanium under 2000N impact forces. Alumina and zirconia implants were found to reduce stresses and strains on the skull and brain compared to titanium implants. However, PMMA implants showed potential for causing skull damage under current loading conditions. Additionally, PMMA and hydroxyapatite implants were prone to fracture. Despite these findings, none of the implants exceeded the limits for tensile and compressive stresses and strains on the brain. Zirconia-reinforced PMMA implants were also shown to reduce stresses and strains on the skull and brain compared to PMMA implants. Alumina and zirconia show promise as alternatives to titanium for the production of cranial implants. The use of alternative implant materials to titanium has the potential to enhance the success of cranial reconstruction by overcoming the limitations associated with titanium implants.

Improved rehabilitation efficiency after cranioplasty in patients with sunken skin flap syndrome: a case series.

PURPOSE: Sunken Skin Flap Syndrome (SSFS) is an uncommon, delayed complication after craniectomy characterized by a functional plateau or decline with variable neurologic symptoms, improving after cranioplasty. SSFS negatively impacts the rehabilitation course, with subjective reports of functional improvement after cranioplasty. However, no studies have assessed the impact of cranioplasty on functional recovery rate. This case series aims to analyze SSFS manifestations and management while awaiting cranioplasty. Also, to assess the role of cranioplasty on rehabilitation outcomes and recovery rate in SSFS patients. METHODS: Four patients were identified with SSFS in inpatient rehabilitation. Each patient had unique clinical manifestations, with multiple strategies used for symptomatic control. Patients spent an average of 23 days in rehabilitation with SSFS symptoms before cranioplasty. After cranioplasty, all patients had SSFS symptom resolution. Comparing change in functional independence measure (FIM) scores and FIM efficiency pre-and post-cranioplasty rehabilitation course, a mean improvement of 23 and 0.72 occurred after cranioplasty, respectively. CONCLUSION: A diagnosis of SSFS should be considered in craniectomy patients exhibiting functional decline or plateau with associated neurological symptoms. This study suggests that FIM and FIM efficiency increases in SSFS patients after cranioplasty, supporting prompt cranioplasty to improve functional outcomes and minimize rehabilitation delays.

Back to the Roots: Reconstructing Large and Complex Cranial Defects using an Image-based Statistical Shape Model.

Designing implants for large and complex cranial defects is a challenging task, even for professional designers. Current efforts on automating the design process focused mainly on convolutional neural networks (CNN), which have produced state-of-the-art results on reconstructing synthetic defects. However, existing CNN-based methods have been difficult to translate to clinical practice in cranioplasty, as their performance on large and complex cranial defects remains unsatisfactory. In this paper, we present a statistical shape model (SSM) built directly on the segmentation masks of the skulls represented as binary voxel occupancy grids and evaluate it on several cranial implant design datasets. Results show that, while CNN-based approaches outperform the SSM on synthetic defects, they are inferior to SSM when it comes to large, complex and real-world defects. Experienced neurosurgeons evaluate the implants generated by the SSM to be feasible for clinical use after minor manual corrections. Datasets and the SSM model are publicly available at https://github.com/Jianningli/ssm .

Treatment of wound infections linked to neurosurgical implants.

As neurosurgery has advanced technologically, more and more neurosurgical implants are being employed on an aging patient population with several comorbidities. As a result, there is a steady increase in the frequency of infections linked to neurosurgical implants, which causes serious morbidity and mortality as well as abnormalities of the skull and inadequate brain protection. We discuss infections linked to internal and external ventricular and lumbar cerebrospinal fluid drainages, neurostimulators, craniotomies, and cranioplasty in this article. Biofilms, which are challenging to remove, are involved in all implant-associated illnesses. It takes a small quantity of microorganisms to create a biofilm on the implant surface. Skin flora bacteria are implicated in the majority of illnesses. Microorganisms that cause disruptions in wound healing make their way to the implant either during or right after surgery. In about two thirds of patients, implant-associated infections manifest early (within the first month after surgery), whereas the remaining infections present later as a result of low-grade infections or by direct extension from adjacent infections (per continuitatem) to the implants due to soft tissue damage. Except for ventriculo-atrial cerebrospinal fluid shunts, neurosurgical implants are rarely infected by the haematogenous route. This research examines established and clinically validated principles that are applicable to a range of surgical specialties using implants to treat biofilm-associated infections in orthopaedic and trauma cases. Nevertheless, there is little evidence and no evaluation in sizable patient populations to support the success of this extrapolation to neurosurgical patients. An optimal microbiological diagnostic, which includes sonicating removed implants and extending culture incubation times, is necessary for a positive result. Additionally, a strategy combining surgical and antibiotic therapy is needed. Surgical procedures involve a suitable debridement along with implant replacement or exchange, contingent on the biofilm's age and the state of the soft tissue. A protracted biofilm-active therapy is a component of antimicrobial treatment, usually lasting 4-12 weeks. This idea is appealing because it allows implants to be changed or kept in place for a single surgical procedure in a subset of patients. This not only enhances quality of life but also lowers morbidity because each additional neurosurgical procedure increases the risk of secondary complications like intracerebral bleeding or ischemia.

[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.

Primary, Dural-based, Ewing sarcoma in a pediatric patient: presentation of a rare tumor entity with literature review.

Primary Ewing's sarcoma originating from the calvaria bone and/or underlying Dural involvement has been reported relatively rarely in the literature. Those originating from the dura and invading the bone above it in both directions, both towards the brain parenchyma and via the dura, are even rarer. CASE DESCRIPTION: We present a case of a 14-year-old girl with no known focal neurological deficit who presented with the complaint of vertigo for only 2 months. In neuroradiological examination, the left frontoparietal region of the brain showed the presence of a tumor originating from the dura, invading both bone and brain parenchyma. No other tumor location was discovered after radiological examination. Since the patient had a shift in the brain and progressive loss of strength on the right side, the patient was taken to surgery for tumor excision. The frozen result sent per-operatively was consistent with a round blue cell tumor. Adjuvant chemotherapy treatment was given to the patient after the definitive pathology report was compatible with Ewing's sarcoma. CONCLUSION: The patient had an uneventful neurological recovery without permanent neurological deficit. When the patient was kept under close clinical and radiological surveillance 1 year after the operation, no recurrence of the disease was observed. Bone marrow biopsy results and pet computerized tomography results confirmed the case of primary intracerebral Ewing sarcoma. This case illustrates an extremely rare location of primary Ewing's sarcoma with a set of clinical signs and symptoms extremely rare for this location of this rare disease entity.

Utilization of carbonated calcium phosphate cement for contouring cranioplasty in patients with syndromic craniosynostosis.

PURPOSE: Carbonated calcium phosphate (CCP) cement is an alloplastic material which has been increasingly utilized for cranioplasty reconstruction; however, there is a paucity of data investigating its use in patients with syndromic craniosynostosis. The purpose of this study was to characterize our institutional experience with CCP cement for secondary contouring cranioplasty in these patients to establish safety and aesthetic efficacy. METHODS: Patients with syndromic craniosynostosis undergoing cranioplasty with CCP cement from 2009 to 2022 were retrospectively reviewed for prior medical and surgical history, cranioplasty size, cement usage, and postoperative complications. Aesthetic ratings of the forehead region were quantified using the Whitaker scoring system at three timepoints: preoperative (T1), < 6 months postoperative (T2), and > 1 year postoperative (T3). RESULTS: Twenty-one patients were included. Age at surgery was 16.2 ± 2.8 years, forehead cranioplasty area was 135 ± 112 cm2, and mass of cement was 17.2 ± 7.8 g. Patients were followed for 3.0 ± 3.1 years. Whitaker scores decreased from 1.9 ± 0.4 at T1 to 1.4 ± 0.5 at T2 (p = 0.005). Whitaker scores at T2 and T3 were not significantly different (p = 0.720). Two infectious complications (9.5%) were noted, one at 4.5 months postoperatively and the other at 23 months, both requiring operative removal of CCP cement. CONCLUSION: Our results suggest that aesthetic forehead ratings improve after CCP contouring cranioplasty and that the improvement is sustained in medium-term follow-up. Complications were uncommon, suggesting that CCP is relatively safe though longer-term follow-up is needed before reaching definitive conclusions.

Cranial vault reduction cranioplasty for severe macrocephaly due to holoprosencephaly and subdural hygroma: a case report.

BACKGROUND: Severe macrocephaly can still be found in developing countries. This condition is usually caused by neglected hydrocephalus and can cause a lot of morbidities. Cranial vault reconstruction cranioplasty is the main treatment option for severe macrocephaly. Holoprosencephaly is often seen with features of microcephaly. Hydrocephalus should be considered as the main cause in HPE patients with features of macrocephaly. In this report, we present a rare case of cranial vault reduction cranioplasty procedure in patient with severe macrocephaly due to holoprosencephaly and subdural hygroma. CASE DESCRIPTION: A 4-year-10-month-old Indonesian boy was admitted with head enlargement since birth. He had a history of VP shunt placement when he was 3 months old. But the condition was neglected. Preoperative head CT showed massive bilateral subdural hygroma that compressed brain parenchyma caudally. From the craniometric calculation, the occipital frontal circumference was 70.5 cm with prominent vertex expansion, the distance between nasion to inion was 11.91 cm and the vertical height was 25.59 cm. The preoperative cranial volume was 24.611 cc. The patient underwent subdural hygroma evacuation and cranial vault reduction cranioplasty. The postoperative cranial volume was 10.468 cc. CONCLUSION: Subdural hygroma can be a rare cause of severe macrocephaly in holoprosencephaly patients. Cranial vault reduction cranioplasty and subdural hygroma evacuation is still the main treatment option. Our procedure successfully reduces significant cranial volume (57.46% volume reduction).

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

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

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.

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.

The intracranial pressure-volume relationship following decompressive hinge craniotomy compared to decompressive craniectomy-a human cadaver study.

OBJECTIVE: Decompressive hinge craniotomy (DHC) is an alternative treatment option to decompressive craniectomy (DC) for elevated intracranial pressure (ICP). The aim of this study was to characterize the difference in pressure-volume relationship between DHC and DC. METHODS: We compared the intracranial pressure-volume relationship in a human cadaver model following either DHC, DC, or fixing of the bone plate by titanium clamps. We inserted an intracranial expandable device in two human cadaver specimens, performed either DHC, DC, or bone plate fixation, and gradually increased the intracranial volume while measuring ICP. Following DHC, we also performed CT-scans at pre-defined intervals. RESULTS: Before ICP exceeded a threshold of 20 mmHg, a fixed bone plate tolerated an increase of 130 ml of intracranial volume, while DHC and DC allowed an increase of 190 ml and 290 ml, respectively. CT-derived calculations following DHC determined that the increase in intracranial volume at ICP 22 mmHg was 65 ml, the maximal increase of intracranial volume was 84 ml, the maximal bone displacement was 21 mm, and the bone plate volume to be 82 ml. Manual stress test of the hinged bone plate did not allow misalignment or intracranial displacement of the bone plate. CONCLUSION: DHC increases the intracranial volume by up to 84 ml and allows for approximately 60 ml increase of intracranial volume before ICP exceeds 20 mmHg. This indicates, when comparing with results from previous studies of herniation volumes, that DHC will be sufficient in many patients with head injury or cerebral infarction with treatment refractory intracranial hypertension.

Cranial meningioma with bone involvement: surgical strategies and clinical considerations.

BACKGROUND: Intracranial meningioma with bone involvement and primary intraosseous meningioma is uncommon. There is currently no consensus for optimal management. This study aimed to describe the management strategy and outcomes for a 10-year illustrative cohort, and propose an algorithm to aid clinicians in selecting cranioplasty material in such patients. METHODS: A single-centre, retrospective cohort study (January 2010-August 2021). All adult patients requiring cranial reconstruction due to meningioma with bone involvement or primary intraosseous meningioma were included. Baseline patient and meningioma characteristics, surgical strategy, and surgical morbidity were examined. Descriptive statistics were performed using SPSS v24.0. Data visualisation was performed using R v4.1.0. RESULTS: Thirty-three patients were identified (mean age 56 years; SD 15) There were 19 females. Twenty-nine patients had secondary bone involvement (88%). Four had primary intraosseous meningioma (12%). Nineteen had gross total resection (GTR; 58%). Thirty had primary 'on-table' cranioplasty (91%). Cranioplasty materials included pre-fabricated polymethyl methacrylate (pPMMA) (n = 12; 36%), titanium mesh (n = 10; 30%), hand-moulded polymethyl methacrylate cement (hPMMA) (n = 4; 12%), pre-fabricated titanium plate (n = 4; 12%), hydroxyapatite (n = 2; 6%), and a single case combining titanium mesh with hPMMA cement (n = 1; 3%). Five patients required reoperation for a postoperative complication (15%). CONCLUSION: Meningioma with bone involvement and primary intraosseous meningioma often requires cranial reconstruction, but this may not be evident prior to surgical resection. Our experience demonstrates that a wide variety of materials have been used successfully, but that pre-fabricated materials may be associated with fewer postoperative complications. Further research within this population is warranted to identify the most appropriate operative strategy.

Analysis of craniectomy bone flaps stored in a neurosurgical cryopreservation freezer: microorganism culture results and reimplantation rates.

BACKGROUND: Cryopreservation of bone flaps after decompressive craniectomies is a common practice. A frequent complication after bone flap reimplantation is postoperative infection, so culturing of frozen craniectomy bone flaps is a crucial practice that can prevent patient morbidity and mortality. Although many studies report on infection rates after cranioplasty, no study reports on the results of bone flaps stored in a cryopreservation freezer, reimplanted or otherwise. We sought to analyze the flaps in our medical center's bone bank freezer, including microorganism culture results and reimplantation rates of cryopreserved bone flaps. METHODS: Patients who underwent craniectomy and had bone flaps cryopreserved between January 1, 2016, and July 1, 2022, were included in this retrospective study. Information about bone flap cultures and reimplantation or discard was obtained from a prospectively maintained cryopreservation database. Information including infection rates and mortality was acquired from a retrospective review of patient records. Culture results were obtained for all flaps immediately before cryopreservation and again at the time of reimplantation at the operator's discretion. RESULTS: There were 148 bone flaps obtained from 145 patients (3 craniectomies were bilateral) stored in our center's freezer. Positive culture results were seen in 79 (53.4%) flaps. The most common microorganism genus was Propionibacterium with 47 positive flaps, 46 (97.9%) of which were P. acnes. Staphylococcus was the second most common with 23 positive flaps, of which 8 (34.8%) tested positive for S. epidermidis. Of the 148 flaps, 25 (16.9%) were reimplanted, 116 (78.4%) were discarded, and 7 (4.7%) are still being stored in the freezer. Postcranioplasty infections were seen in 3 (12%) patients who had flap reimplantation. CONCLUSIONS: Considering the substantial number of positive cultures and limited reimplantation rate, we have reservations about the logistical efficiency of cryopreservation for flap storage. Future multicenter studies analyzing reimplantation predictors could help to reduce unnecessary freezing and culturing.