Neuropsychological changes and cranioplasty: A group analysis

Predictive factors influencing outcome of early cranioplasty after decompressive craniectomy: a outcome prediction model study

Objective

The timing of cranioplasty (CP) has become a widely debated topic in research, there is currently no unified standard. To this end, we established a outcome prediction model to explore the factors influencing the outcome of early CP. Our aim is to provide theoretical and practical basis for whether patients with skull defects after decompressive craniectomy (DC) are suitable for early CP.

Methods

A total of 90 patients with early CP after DC from January 2020 to December 2021 were retrospectively collected as the training group, and another 52 patients with early CP after DC from January 2022 to March 2023 were collected as the validation group. The Nomogram was established to explore the predictive factors that affect the outcome of early CP by Least absolute shrinkage analysis and selection operator (LASSO) regression and Logistic regression analysis. Receiver operating characteristic (ROC) curve was used to evaluate the discrimination of the prediction model. Calibration curve was used to evaluate the accuracy of data fitting, and decision curve analysis (DCA) diagram was used to evaluate the benefit of using the model.

Results

Age, preoperative GCS, preoperative NIHSS, defect area, and interval time from DC to CP were the predictors of the risk prediction model of early CP in patients with skull defects. The area under ROC curve (AUC) of the training group was 0.924 (95%CI: 0.867-0.980), and the AUC of the validation group was 0.918 (95%CI, 0.842-0.993). Hosmer-Lemeshow fit test showed that the mean absolute error was small, and the fit degree was good. The probability threshold of decision risk curve was wide and had practical value.

Conclusion

The prediction model that considers the age, preoperative GCS, preoperative NIHSS, defect area, and interval time from DC has good predictive ability.

Earlier cranioplasty following posttraumatic craniectomy is associated with better neurological outcomes at one-year follow-up: a two-centre retrospective cohort study

PURPOSE

Cranioplasty (CP) after decompressive craniectomy (DC) is routinely performed for reconstructive purposes and improves rehabilitation. However, the optimal timing of CP remains controversial. This study aimed to assess differences in clinical outcomes following different timings of CP in patients with traumatic brain injury.

MATERIALS AND METHODS

Patients with traumatic brain injury who underwent CP after DC in Zhongnan Hospital of Wuhan University from 1 January 2010 to 1 May 2017, and in Affiliated Hospital of Guizhou Medical University from 1 January 2015, to 1 May 2017, were retrospectively reviewed. According to the timing of CP, patients were divided into an 'early group' (3-6 months) and a 'late group' (6-12 months). The clinical characteristics of patients and postoperative complications occurred within 1-year follow-up were analysed. The neurological function was assessed with Barthel Index (BI).

RESULTS

A total of 100 patients (58 cases in early group and 42 cases in late group) were included. The median interval between DC and CP was 135 days and 225 days in the early and late CP groups, respectively. The overall complication rate after CP was 16%, and no significant difference in complication rate was observed between the early and late CP groups (17.2% vs.14.3%, p = 0.69). The neurological function was improved in early CP group (pre-CP 85.77 ± 11.61 vs. post-CP 95.34 ± 9.02, p < 0.001, but not in late CP group (pre-CP 82.74 ± 22.82 vs. post-CP 88.93 ± 22.86, p = 0.22). In addition, a significantly higher proportion of patients in the early CP group showed neurological functional improvement in comparison with the late CP group (early vs. late: 74.1% vs. 57.1%, p = 0.04). Multivariate analysis further demonstrated that the timing of CP is an independent predictor for neurological outcomes (OR = 0.32, 95% CI 0.13-0.82, p = 0.02).

CONCLUSION

Early CP (3-6 months) following posttraumatic DC was associated with better neurological outcomes than late CP (>6 months).

Towards a core outcome set for cranioplasty following traumatic brain injury and stroke 'A systematic review of reported outcomes'

Background

There is wide-ranging published literature around cranioplasty following traumatic brain injury (TBI) and stroke, but the heterogeneity of outcomes limits the ability for meta-analysis. Consensus on appropriate outcome measures has not been reached, and given the clinical and research interest, a core outcome set (COS) would be beneficial.

Objectives

To collate outcomes currently reported across the cranioplasty literature which will subsequently be used in developing a cranioplasty COS.

Methods

This systematic review adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. All full-text English studies with more than ten patients (prospective) or more than 20 patients (retrospective) published after 1990 examining outcomes in CP were eligible for inclusion.

Results

The review included 205 studies from which 202 verbatim outcomes were extracted, grouped into 52 domains, and categorised into one or more of the OMERACT 2.0 framework core area(s). The total numbers of studies that reported outcomes in the core areas are 192 (94%) pathophysiological manifestations/ 114 (56%) resource use/economic impact/ 94 (46%) life impact/mortality 20 (10%). In addition, there are 61 outcome measures used in the 205 studies across all domains.

Conclusion

This study shows considerable heterogeneity in the types of outcomes used across the cranioplasty literature, demonstrating the importance and necessity of developing a COS to help standardise reporting across the literature.

Effect of cranioplasty on FIM in patients with severe cerebral infarction after cerebral decompression

Arai N, Abe Y, Metani H, Hiraoka T, Hanayama K. Effect of cranioplasty on FIM in patients with severe cerebral infarction after cerebral decompression. Jpn J Compr Rehabil Sci 2023; 14: 33-38.

Objective

The functional effects of cranioplasty were measured in patients with severe cerebral infarction who had undergone cerebral decompression by comparing the functional independence measure (FIM) during convalescent rehabilitation before and after cranioplasty.

Methods

The study design was a single-center retrospective cohort study.

Results

Fifty-five patients underwent cerebral decompression after cerebral infarction at our hospital, six of whom were included in this study. Two patients who exhibited cranial depression had no changes in FIM one month prior to cranioplasty. However, the FIM increased one month postoperatively. These patients showed a large increase in the scores for movement and transfer.

Discussion

Cranioplasty may play a role in improving ability during convalescent rehabilitation in patients with severe cerebral infarction who undergo cerebral decompression, especially in movement and transfer items.

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.

[Surgical treatment of patients with skull defects and cerebrospinal fluid flow disorders after previous decompressive craniectomy]

Decompressive craniectomy (DC) is performed for refractory intracranial hypertension following severe traumatic brain injury, vascular and oncological diseases. This fact increases the number of patients with extensive and giant skull defects. Cerebrospinal fluid (CSF) flow disorders after DC are often accompanied by ventriculomegaly. However, only some patients with ventriculomegaly have hydrocephalus and require CSF bypass procedures. Differentiation of post-traumatic hydrocephalus requiring surgical treatment and atrophic dilation of ventricular system «ex vacuo» caused by brain injury is still an important issue. Skull sealing as a way to normalize CSF circulation and eliminate hydrocephalus is also an open question. Currently, there is no unified approach to patients with extensive and giant cranial defects combined with post-traumatic hydrocephalus. There is no unified algorithm for sequence of reconstructive and CSF bypass operations in these patients. Literature data on risks of infectious complications for different surgical strategies are controversial.

Predictors of Clinical Outcomes in Autologous Cranioplasty

BACKGROUND

Cranioplasty is a common neurosurgical procedure and autologous grafts are preferred due to their aesthetic and biocompatibility benefits. Multiple risk factors are implicated as predictors for neurologic outcome. This study focuses on risk factors that may be associated with complications and analyzes the predictors of neurologic outcomes after autologous cranioplasty.

METHODS

This is a retrospective observational study conducted at a tertiary care center between 2015 and 2021. Adults with autologous cranioplasty (n = 132) were recruited from procedure logs and the hospital electronic health record. Clinicodemographic parameters, risk factors, and complications were recorded. Neurologic outcomes were measured using the dichotomized Glasgow Outcome Scale (GOS). Primary outcome measure was pre- and post-cranioplasty GOS at the last follow up. Secondary outcome measures were the predicting factors that contributed to enhanced neurologic outcome post-cranioplasty.

RESULTS

Mean age was 41.4 (standard deviation ± 13.5) years with male predominance (12.2:1). Complications developed in 12.9% (n = 17), with infections in 3.8% (n = 5) and hydrocephalus in 2.3% (n = 3). In bivariate analysis, pre-cranioplasty GOS good grades 4 and 5 (P < 0.001), trauma as an indication for decompressive craniectomy (DC) (P < 0.001), and early cranioplasty ≤12 weeks (P = 0.023) were statistically significant predictors for post-cranioplasty neurologic recovery at follow-up. In a multiple logistic regression model, adjusted odds ratio for pre-cranioplasty GOS was 28.77 (95% confidence interval [CI] 7.21-114.74, P < 0.001), for trauma as indication for DC was 5.15 (95% CI 1.65-16.05, P = 0.003), and for early cranioplasty ≤12 weeks was 3.04 (95% CI 1.12-8.27 P = 0.029).

CONCLUSIONS

Autologous cranioplasty contributes to a quantifiable neurologic outcome. Pre-cranioplasty neurologic status, cranioplasty done for traumatic DC and early cranioplasty may have potential for enhanced neurologic recovery. Further clinical studies with better evidence may expound upon these findings.

Cranioplasty: A Multidisciplinary Approach

Decompressive craniectomy (DC) is an operation where a large section of the skull is removed to accommodate brain swelling. Patients who survive will usually require subsequent reconstruction of the skull using either their own bone or an artificial prosthesis, known as cranioplasty. Cranioplasty restores skull integrity but can also improve neurological function. Standard care following DC consists of the performance of cranioplasty several months later as historically, there was a concern that earlier cranioplasty may increase the risk of infection. However, recent systematic reviews have challenged this and have demonstrated that an early cranioplasty (within three months after DC) may enhance neurological recovery. However, patients are often transferred to a rehabilitation unit following their acute index admission and before their cranioplasty. A better understanding of the pathophysiological effects of cranioplasty and the relationship of timing and complications would enable more focused patient tailored rehabilitation programs, thus maximizing the benefit following cranioplasty. This may maximise recovery potential, possibly resulting in improved functional and cognitive gains, enhancement of quality of life and potentially reducing longer-term care needs. This narrative review aims to update multi-disciplinary team regarding cranioplasty, including its history, pathophysiological consequences on recovery, complications, and important clinical considerations both in the acute and rehabilitation settings.

Microsurgical scalp reconstruction and cranioplasty refined

Introduction: Microsurgical free flap scalp reconstruction is commonly the only reconstructive option in certain challenging patient cohorts. We describe the technical refinements that have streamlined our ap-proach to microsurgical scalp reconstruction and cranioplasty. Methods: Virtual surgical planning for multiple failed cranioplasty cases involves fashioning an implant with a 3 mm offset. Intramuscular dissection of the latissimus dorsi (LD) vascular pedicle, distal to its bifurcation, is routinely performed, and can increase pedicle length by up to 4 cm without the need for tedious dissec-tion in the axilla. Anastomoses to the superficial temporal vessels distal to their bifurcation in the parietal scalp are reliable and safe. The sequence of surgery is in reverse to the conventional sequence, with the free flap vascularised before craniectomy/cranioplasty is performed to decrease the duration of synthetic im-plant exposure. Results: Thirty-nine cases were performed in 35 patients over a five-year period. An LD-based free flap in various permutations was the commonest free flap option (n = 31). The superficial temporal artery and vein were choice recipient vessels in 82 per cent and 74 per cent of cases, respectively, with the former demon-strating higher anatomical consistency. Complications included free flap venous congestion successfully salvaged (n = 1), infected polymethylmethacrylate cranioplasty requiring explantation (n = 1), subdural haematoma requiring craniotomy for evacuation (n = 1) and free flap donor site haematoma (n = 2). Conclusion: Our technical refinements offer a streamlined and reliable procedure of complex scalp recon-struction and cranioplasty.

Characteristics of Patients with Trephine Syndrome: A Retrospective Study

Objectives:

This study retrospectively investigated the prevalence and clinical features of trephine syndrome, which is a late complication of craniectom, in patients who underwent craniectomy decompression.

Methods:

Trephine syndrome was defined as an increase of ≥2 points in the functional independent measure (FIM) score at 7 days after cranioplasty compared with that 3 days before cranioplasty. Patients who underwent craniectomy at Kawasaki Medical School Hospital between January 1, 2010, and March 15, 2020, were included in the study.

Results:

During the observation period, 102 patients underwent craniectomy decompression; 71 of them later underwent cranioplasty. In total, 12 and 59 patients were assigned to the trephine and non-trephine syndrome groups, respectively. The patients in the trephine syndrome group were significantly younger than those in the non-trephine syndrome group (P<0.05). The mean durations±standard deviations (in days) from craniectomy decompression to cranioplasty were 57.1±38.9 and 83.6±69.3 for the trephine and non-trephine syndrome groups, respectively (P<0.05). Improvements in the FIM motor scores were greater than the improvements in the cognitive scores for all but one case (P<0.05). The frequency with which patients experienced exacerbation (worsened consciousness and sudden anisocoria) after hospitalization was significantly higher in the trephine syndrome group than in the non-trephine syndrome group (P<0.05).

Conclusions:

Performing cranioplasty as early as possible in young patients may lead to functional improvement. In the trephine syndrome group, the improvement in motor FIM score was greater than that of the cognitive score. Moreover, post-hospitalization exacerbation was more frequent in the trephine syndrome group.

Surface Area of Decompressive Craniectomy Predicts Bone Flap Failure after Autologous Cranioplasty: A Radiographic Cohort Study

Skull bone graft failure is a potential complication of autologous cranioplasty after decompressive craniectomy (DC). Our objective was to investigate the association of graft size with subsequent bone graft failure after autologous cranioplasty. This single-center retrospective cohort study included patients age ≥18 years who underwent primary autologous cranioplasty between 2010 and 2017. The primary outcome was bone flap failure requiring graft removal. Demographic, clinical, and radiographic factors were recorded; three-dimensional (3D) reconstructive imaging was used to perform accurate measurements. Univariate and multi-variate regression analysis were performed to identify risk factors for the primary outcome. Of the 131 patients who underwent primary autologous cranioplasty, 25 (19.0%) underwent removal of the graft after identification of bone flap necrosis on computed tomography (CT); 16 (64%) of these were culture positive. The mean surface area of craniectomy defect was 128.5 cm² for patients with bone necrosis and 114.9 cm² for those without bone necrosis. Linear regression analysis demonstrated that size of craniectomy defect was independently associated with subsequent bone flap failure; logistic regression analysis demonstrated a defect area >125 cm² was independently associated with failure (odds ratio [OR] 3.29; confidence interval [CI]: 0.249-2.135). Patient- and operation-specific variables were not significant predictors of bone necrosis. Our results showed that increased size of antecedent DC is an independent risk factor for bone flap failure after autologous cranioplasty. Given these findings, clinicians should consider the increased potential of bone flap failure after autologous cranioplasty among patients whose initial DC was >125 cm².

Different materials of cranioplasty for patients undergoing decompressive craniectomy: A protocol for systematic review and network meta-analysis

BACKGROUND

Cranioplasty is widely applied on patients who has undergone decompress craniectomy (DC) due to intractable increased intracranial pressure and the cranioplasty materials have been on the bleeding edge of biomolecular and material science. This systematic review and network meta-analysis (NMA) will be conducted to comprehensively evaluate the safety and efficacy of different cranial implants for patients with cranial defects due to various reasons.

METHODS AND ANALYSIS

This protocol has been reported following the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols. The following electronic databases will be searched from the date of database establishment to September 1, 2020: PubMed, Embase, Cochrane Library, Web of Science, China National Knowledge Infrastructure, VIP, and Wanfang. Randomized controlled trials and non-randomized prospective studies focus on cranial implants will be included. Quality assessment will be conducted using Cochrane Collaboration's tool or risk of bias in nonrandomized studies of interventions based on their study designs. The primary outcome will be postoperative early mortality and implant failure while various complications for secondary outcomes. Pairwise and network meta-analysis will be conducted using STATA V.14 (StataCorp, College Station, Texas, USA). Subgroup analyses and sensitivity analyses will be conducted to assess the robustness of the results.

ETHICS AND DISSEMINATION

This systematic review does not require an ethics approval or the need to obtain informed consent. The results will be published in a peer-reviewed scientific journal.

PROTOCOL REGISTRATION NUMBER

INPLASY 202110001.

Changes in the prefronto-thalamic tract following cranioplasty: Case reports

RATIONALE

The prefrontothalamic tract (PTT) injury is associated with various neuropsychological impairments including cognitive impairment. We report on three women with hemorrhagic stroke who showed changes in the PTT following cranioplasty (C/P) using diffusion tensor tractography (DTT) images.

PATIENT CONCERNS

The 3 women with hemorrhagic stroke showed reductions of cognitive impairment following C/P. Mini-Mental State Examination scores (MMSE) were increased by 7-, 8-, and 5-point in patient 1, 2, and 3, respectively, after C/P compared with the patients' pre-C/P MMSE scores.

DIAGNOSIS

Three patients were diagnosed with spontaneous intracerebral hemorrhage. Three patients underwent C/P using auto-bone at 7 (patient 1 and 3) and 13 (patient 2) weeks after onset.

INTERVENTIONS

Diffusion tensor imaging data were acquired within 3 days before and 21 days after C/P.

OUTCOMES

The pre-C/P DTT results showed non-reconstruction of the dorsolateral prefrontal cortex (DLPFC; patient 2 and 3) on the contralateral operation (contra-OP) side and orbitofrontal cortex (OFC; patient 3) on both sides, but those were reconstructed on post-C/P DTT. Except for the contra-OP side OFC of patient 2, all fractional anisotropy values decreased on post-C/P DTT compared with pre-C/P DTT. The mean diffusivity values of the VLPFC and OFC were higher on post-C/P DTT except for the contra-OP side VLPFC of patient 1 and contra-OP side OFC of patient 2. The voxel numbers also increased except for the contra-OP side VLPFC of patient 1.

LESSONS

We demonstrated structural changes in the PTT along with concomitant reductions of cognitive impairments following C/P in 3 women with hemorrhagic stroke using DTT. The DTT changes suggest that C/P can affect the state of the PTT on both the OP and contra-OP sides. However, the limitation that DTT analysis may underestimate or overestimate fiber tract status due to regions of fiber complexity and crossing fiber should be considered.

Patients with ventricular assist device and cerebral entrapment-Supporting skullcap reimplantation

Effects of cranioplasty (CP) and skullcap reimplantation after decompressive craniectomy (DC) for cerebral hemorrhage or malignant brain infarction in patients with left ventricular assist device (LVAD) support as bridge to transplantation has not been surveyed yet. The aim of this study was to evaluate outcome and management after CP when aiming for transplantation. Data were collected from our prospective institutional database including all patients undergoing LVAD implantation between 2010 and 2019. Six patients needed CP procedures and were included. Our analysis focused on postoperative outcome, survival, and facilitation of heart transplantation. Study endpoints included also all-cause mortality. From a total of 1010 LVAD implantations during analysis period in our center, six bridge-to-transplantation LVAD patients [median age at LVAD implantation: 32.5 years (IQR: 24.8-39.5 years); four male, HVAD, n = 3; HM II, n = 1; HM 3, n = 2] underwent CP with imminent entrapment secondary to cerebral hemorrhage or malignant infarction. Primary heart failure etiology was myocarditis (n = 2), dilated (n = 2), or ischemic (n = 2). Median INTERMACS class was 1.5 (IQR; 1.0-2.8). Median time on LVAD support to DC procedure was 33 months (IQR: 16-48 months). The indication for DC was intraparenchymal hemorrhage (n = 4), subdural hematoma (n = 1), and malignant middle cerebral artery infarction (n = 1). After a median time of 4 months (IQR: 3.3-4.0 months, range; 2.0-10 months) post DC procedure, CP was subsequently performed without profound neurologic disabilities in all patients. After median time of 26 months (IQR: 21-42 months) follow-up, three patients successfully received heart transplantation, one patient could undergo LVAD explantation for myocardial recovery, and the remaining two patients are still on the list awaiting heart transplantation. CP procedure with skullcap reimplantation is feasible and can be safely performed in LVAD patients, which subsequently may even be eligible for heart transplantation with beneficial prognosis.

Super early cranial repair improves the prognosis of patients with craniocerebral injury

Objective

Craniocerebral injury has high disability and mortality rates. The timing of cranioplasty has an important impact on patients’ prognosis. This study was performed to compare the functional prognosis between super early repair and conventional repair.

Methods

This observational study included 60 patients who underwent cranioplasty after surgical treatment of severe craniocerebral trauma. The patients were divided into two groups according to the time of cranial repair after the surgical treatment of craniocerebral injury: the super early group and the conventional repair group. Sex, age, Karnofsky performance status (KPS) score, Zubrod performance status (ZPS) score, psychological function score, quality of life score, and complications were recorded.

Results

The KPS score, ZPS score, psychological function score, and quality of life score were significantly related to the intervention period. Each of these scores had a clear correlation with the performance of super early treatment.

Conclusion

Super early cranial repair does not increase the incidence of surgical complications, and it can improve the postoperative KPS, ZPS, and quality of life scores.

Biomaterial and implant induced ossification: in vitro and in vivo findings

Material-induced ossification is suggested as a suitable approach to heal large bone defects. Fiber-reinforced composite-bioactive glasses (FRC-BGs) display properties that could enhance the ossification of calvarial defects. Here, we analyzed the healing processes of a FRC-BG implant in vivo from the perspective of material-induced ossification. Histological analysis of the implant, which was removed 5 months after insertion, showed the formation of viable, noninflammatory mesenchymal tissue with newly-formed mineralized woven bone, as well as nonmineralized connective tissue with capillaries and larger blood vessels. The presence of osteocytes was detected within the newly generated bone matrix. To expand our understanding on the osteogenic properties of FRC-BG, we cultured human adipose tissue-derived mesenchymal stromal cells (AD-MSCs) in the presence of two different BGs (45S5 and S53P4) and Al2 O3 control. AD-MSCs grew and proliferated on all the scaffolds tested, as well as secreted abundant extracellular matrix, when osteogenic differentiation was appropriately stimulated. 45S5 and S53P4 induced enhanced expression of COL2A1, COL10A1, COL5A1 collagen subunits, and pro-osteogenic genes BMP2 and BMP4. The concomitant downregulation of BMP3 was also detected. Our findings show that FRC-BG can support the vascularization of the implant and the formation of abundant connective tissue in vivo. Specifically, BG 45S5 and BG S53P4 are suited to evoke the osteogenic potential of host mesenchymal stromal cells. In conclusion, FRC-BG implant demonstrated material-induced ossification both in vitro and in vivo.

Cranioplasty: A Comprehensive Review of the History, Materials, Surgical Aspects, and Complications

Cranioplasty is a common neurosurgical procedure performed to reconstruct cranial defects. The materials used to replace bone defects have evolved throughout history. Cranioplasty materials can be broadly divided into biological and synthetic materials. Biological materials can be further subdivided into autologous grafts, allografts, and xenografts. Allografts (bony materials and cartilage from cadavers) and xenografts (bony materials from animals) are out of favor for use in cranioplasty because of their high rates of infection, resorption, and rejection. In autologous cranioplasty, either the cranial bone itself or bones from other parts of the body of the patient are used. Synthetic bone grafts have reduced the operation time and led to better cosmetic results because of the advancement of computer-based customization and three-dimensional printing. Aluminum was the first synthetic bone graft material used, but it was found to irritate neural tissue, induce seizures, and dissolve over time. Acrylic, in the form of methyl methacrylate, is the most widely used material in cranioplasty. Hydroxyapatite is a natural component of bone and is believed to enhance bone repair, resulting in decreased tissue reactions and promoting good osteointegration. Polyetheretherketones are light and nonconductive and do not interfere with imaging modalities. The complication rates of cranioplasty are high, and surgical site infection is the most common complication. The effect of cranioplasty timing on cognitive function remains debatable. However, the timing of cranioplasty is independent of neurologic outcomes. In this article, the history, materials, complications, and evolution of current practices used in cranioplasty are comprehensively reviewed.

Evaluation of titanium mesh cranioplasty and polyetheretherketone cranioplasty: protocol for a multicentre, assessor-blinded, randomised controlled trial

INTRODUCTION

Cranioplasty is a common surgery in neurosurgery department. However, restoring the integrity of skull brings many challenges to surgeons, and the selection of ideal implant materials is throughout the history of cranioplasty. Although titanium mesh was still preferred by many neurosurgeons in cranial reconstruction, the new polyetheretherketone (PEEK) material, for example, is gaining popularity for craniofacial reconstruction today. There remain limited data that compare the outcome of PEEK cranioplasty and titanium mesh cranioplasty. It is necessary to conduct a study to compare outcome of different materials for cranioplasty.

METHODS/DESIGN

In this multicentre, assessor-blinded, randomised controlled study, we will randomise 140 patients in a 1:1 ratio to PEEK cranioplasty versus titanium cranioplasty. Eligible patients are adults who were diagnosed with cranial defect (due to severe traumatic brain injury, ischaemic stroke, haemorrhagic stroke, infiltrative tumour and so on), the defect size is over 25 cm², and they need to agree to participate in this trial. Instead of standard examinations, the enrolled patients receive neurological, motor, cognitive function and cerebral hemodynamics examinations as well as cosmetic evaluation. The procedures are repeated 3, 6 months after cranioplasty. The primary outcome, defined as infection or implant exposure after surgery, is the implant failure rate within 6 months. Secondary outcomes include postoperative complication rates, neurological outcomes, motor function, cerebral hemodynamics, cosmetic outcome and the total cost over a 6-month period.

ETHICS AND DISSEMINATION

This trial protocol has been approved by Biomedical Research Ethics Committee of West China Hospital of Sichuan University. All patients will be fully informed the implant materials, potential complications after surgery, responsibilities during the trial, and they will sign the informed consent before joining in this trial. If the patient's cognitive function is impaired, the patient's next of kin would be carefully informed. The results will be disseminated through academic conferences, student theses and will be published in a peer-reviewed journal.

TRAIL REGISTRATION NUMBER

ChiCTR1900024625; Pre-results.

Polymethylmethacrylate patient-matched implants (PMMA-PMI) for complex and revision cranioplasty: analysis of long-term complication rates and patient outcomes

Objective: Cranioplasty (CP) is associated with high complication rates and patient-matched implants (PMI) are frequently used for CP. However, only limited data are available regarding complication rates of PMI-based CP after complex or failed primary CP. Here we report our experience with the use of polymethylmethacrylate (PMMA) PMI for this purpose.Method: We analyzed all patients with complex or failed primary CP and subsequent implantation of PMMA-PMI between 2010 and 2015 at our institution.Results: A total of 67 patients (29 females, 38 males) with a mean age of 43 years (range: 13-74 years) were included in the study. Primary PMI-CP was performed in 18 patients with destructive or osteolytic bone tumors. Secondary PMI-CP was performed in 49 patients. Complications occurred in 14 patients with an overall complication rate of 21.7% during a mean follow-up of 39.7 ± 23.4 month. Approximately two-thirds of the patients reported a good quality of life after the initial event and subsequent CP. The majority of patients (>90%) was satisfied with the cosmetic result.Conclusion: Surgical CP with PMMA-PMI appears to be a suitable method for patients with failed or complex CP. Complication rates are comparable to those reported for primary CP.

Strokectomy and Extensive Cisternal CSF Drain for Acute Management of Malignant Middle Cerebral Artery Infarction: Technical Note and Case Series

Background and Purpose: Ischemic stroke is a major cause of death and disability worldwide. Large MCA stroke may evolve as malignant space occupying lesion and mortality rate reaches 80% despite maximal medical therapy. Early decompressive craniectomy is effective in reducing mortality and improving the functional outcome but is an extended and invasive surgical approach burdened with a significant complication rate. We report a surgical treatment based on partial strokectomy and basal cisterns opening with massive CSF drain.

Materials and Methods: We retrospectively collected 15 cases of massive middle cerebral artery stroke treated with strokectomy between 2010 and 2017: nine males and six females, mean age 61.73 ± 9.5 years. The right side was affected in 66.7%. All patients show clinical deterioration despite standard medical therapy and indication for surgery was placed after collegiate evaluation by neurologists and neurosurgeons based on clinical and radiological data.

Results: Surgical procedure was performed 24–96 h after the stroke onset. All the 15 patients survived the intervention, one patient died 20 days after the admission for massive lung embolism. Mean GCS and NIHSS at admission were 12.6 ± 1.18 (range 9–15) and 19.7 ± 2.3 (range 18–23), respectively. Mean mRS at 12 months was 3.6 ± 1.1 (range 2–6). Mean follow-up was 18.1 months (range 12–34). The outcome was evaluated as satisfactory (mRs ≤ 3) in 8 patients (53.3%). Mortality at 1 year was 6.7%. No patients developed hydrocephalus and 1 presented seizures. According to mRs outcome evaluation (mRs ≤ 3 vs. mRs ≥ 4) no quantitative variable resulted significantly different between the two groups, whereas the concomitant use of iv rTPA significantly differed (P < 0.05).

Conclusion: Supratentorial strokectomy seems to be safe and could be a potential alternative to decompressive craniectomy for the acute management of malignant MCA stroke. Advantages of this approach could be low complication rate, avoidance of bone reconstruction procedure, and reduced occurrence of hydrocephalus or seizures. A co-operative multicentric, prospective pilot study will be necessary to validate this technical approach.

[Modern aspects of reconstructive surgery of skull defects]

The aim of this study is to systematize the modern methods used for reconstruction of extensive and complex skull defects. Special attention is paid to computer technologies, including 3D imaging and CAD/CAM. Laser-based stereolithography is thoroughly reviewed among other additive technologies. We present our view of the problem associated with proper timing of cranioplasty and choice of materials for it. Complications of skull defect reconstruction are also discussed.

Long-Term Complications of Cranioplasty Using Stored Autologous Bone Graft, Three-Dimensional Polymethyl Methacrylate, or Titanium Mesh After Decompressive Craniectomy: A Single-Center Experience After 596 Procedures

OBJECTIVE

Cranioplasty is a technically simple procedure intended to repair defects of the skull to provide protection after craniectomy, improve functional outcomes, and restore cosmesis. Several materials have been used for the restoration of skull defects, including autologous bone grafts (AGs), polymethyl methacrylate (PMMA) flaps, and titanium mesh (T-mesh). However, the long-term results of cranioplasty after use of these materials are controversial.

METHODS

Medical records of 596 patients who underwent cranioplasty at our medical center between 2009 and 2015 with at least 2.5 years of follow-up were retrospectively reviewed. Patients were classified into 3 groups according to the materials used: AG, three-dimensional PMMA, and T-mesh. Demographic and clinical characteristics and postoperative complications were analyzed.

RESULTS

Cranioplasty with AG had the highest bone flap depression rate (4.9%; P = 0.02) and was associated with a 26% long-term bone flap resorption. Younger age was a risk factor for bone flap resorption. T-mesh had a higher risk of postoperative skin erosion and bone exposure (17%; P = 0.004). Patients with diabetes, previous craniotomy, or hydrocephalus showed a higher risk of postoperative skin erosion. PMMA was associated with the highest rate of postoperative infection (14.4% <3 months, 28.1% >3 months; P < 0.05), and previous craniotomy may increase the infection risk after cranioplasty with PMMA.

CONCLUSIONS

Complications after cranioplasty are high, and the various types of cranioplasty materials used are associated with different complications. Surgeons need to be aware of these potential complications and should choose the appropriate material for each individual patient.

Predictors of primary autograft cranioplasty survival and resorption after craniectomy

OBJECTIVE

Craniectomy is a common neurosurgical procedure that reduces intracranial pressure, but survival necessitates cranioplasty at a later stage, after recovery from the primary insult. Complications such as infection and resorption of the autologous bone flap are common. The risk factors for complications and subsequent bone flap removal are unclear. The aim of this multicenter, retrospective study was to evaluate the factors affecting the outcome of primary autologous cranioplasty, with special emphasis on bone flap resorption.

METHODS

The authors identified all patients who underwent primary autologous cranioplasty at 3 tertiary-level university hospitals between 2002 and 2015. Patients underwent follow-up until bone flap removal, death, or December 31, 2015.

RESULTS

The cohort comprised 207 patients with a mean follow-up period of 3.7 years (SD 2.7 years). The overall complication rate was 39.6% (82/207), the bone flap removal rate was 19.3% (40/207), and 11 patients (5.3%) died during the follow-up period. Smoking (OR 3.23, 95% CI 1.50-6.95; p = 0.003) and age younger than 45 years (OR 2.29, 95% CI 1.07-4.89; p = 0.032) were found to independently predict subsequent autograft removal, while age younger than 30 years was found to independently predict clinically relevant bone flap resorption (OR 4.59, 95% CI 1.15-18.34; p = 0.03). The interval between craniectomy and cranioplasty was not found to predict either bone flap removal or resorption.

CONCLUSIONS

In this large, multicenter cohort of patients with autologous cranioplasty, smoking and younger age predicted complications leading to bone flap removal. Very young age predicted bone flap resorption. The authors recommend that physicians extensively inform their patients of the pronounced risks of smoking before cranioplasty.

Factors related to failure of autologous cranial reconstructions after decompressive craniectomy

PURPOSE

Cranioplasty is customary after decompressive craniectomy. Many different materials have been developed and used for this procedure. The ideal material does not yet exist, while complication rates in cranioplasties remain high. This study aimed to determine factors related to autologous bone flap failure.

MATERIALS AND METHODS

In this two-center retrospective cohort study, 276 patients underwent autologous bone cranioplasty after initial decompressive craniectomy between 2004 and 2014. Medical records were reviewed regarding patient characteristics and factors potentially related to bone flap failure. Data were analyzed using univariable and multivariable regression analysis.

RESULTS

Independent factors related to overall bone flap failure were: duration of hospitalization after decompressive craniectomy [OR: 1.012 (95%CI: 1.003-1.022); p = 0.012], time interval between decompressive craniectomy and cranioplasty [OR: 1.018 (95%CI: 1.004-1.032); p = 0.013], and follow-up duration [OR: 1.034 (95%CI: 1.020-1.047); p < 0.001]. In patients with bone flap infection, neoplasm as initial diagnosis occurred significantly more often (29.2% vs. 7.8%; RD 21.3%; 95%CI 8.4 -38.3%; NNH 5; 95%CI 3 -12) and duration of hospitalization after decompressive craniectomy tended to be longer (means 54 vs. 28 days, MD 26.2 days, 95%CI -8.6 to 60.9 days). Patients with bone flap resorption were significantly younger (35 vs. 43 years, MD 7.7 years, 95%CI 0.8-14.6 years) and their cranial defect size tended to be wider than in patients without bone flap resorption (mean circumference 39 vs. 37 cm; MD 2.4 cm, 95% CI -0.43-5.2 cm) and follow-up duration was significantly longer (44 vs. 14 months, MD 29 months, 95%CI 17-42 months).

CONCLUSION

A neoplasm as initial diagnosis, longer hospitalization after decompressive craniectomy, larger time interval between decompressive craniectomy and cranioplasty, and longer follow-up duration are associated with a higher risk of failure of autologous bone flaps for cranioplasty. Patients with these risk factors may be better served with an early recovery program after decompressive surgery or an alloplastic material for cranioplasty.

Quantitative and qualitative analysis of bone flap resorption in patients undergoing cranioplasty after decompressive craniectomy

OBJECTIVE: Autologous bone cranioplasty after decompressive craniectomy entails a notable burden of difficult postoperative complications, such as infection and bone flap resorption (BFR), leading to mechanical failure. The prevalence and significance of asymptomatic BFR is currently unclear. The aim of this study was to radiologically monitor the long-term bone flap survival and bone quality change in patients undergoing autologous cranioplasty. METHODS: The authors identified all 45 patients who underwent autologous cranioplasty at Oulu University Hospital, Finland, between January 2004 and December 2014. Using perioperative and follow-up CT scans, the volumes and radiodensities of the intact bone flap prior to surgery and at follow-up were calculated. Relative changes in bone flap volume and radiodensity were then determined to assess cranioplasty survival. Sufficient CT scans were obtainable from 41 (91.1%) of the 45 patients. RESULTS: The 41 patients were followed up for a median duration of 3.79 years (25th and 75th percentiles = 1.55 and 6.66). Thirty-seven (90.2%) of the 41 patients had some degree of BFR and 13 (31.7%) had a remaining bone flap volume of less than 80%. Patients younger than 30 years of age had a mean decrease of 15.8% in bone flap volume compared with the rest of the cohort. Bone flap volume was not found to decrease linearly with the passing of time, however. The effects of lifestyle factors and comorbidities on BFR were nonsignificant. CONCLUSIONS: In this study BFR was a very common phenomenon, occurring at least to some degree in 90% of the patients. Decreases in bone volume were especially prominent in patients younger than 30 years of age. Because the progression of resorption during follow-up was nonlinear, routine follow-up CT scans appear unnecessary in monitoring the progression of BFR; instead, clinical follow-up with mechanical stability assessment is advised. Partial resorption is most likely a normal physiological phenomenon during the bone revitalization process.

Timing for cranioplasty to improve neurological outcome: A systematic review

INTRODUCTION

Cranioplasty is a surgical technique applied for the reconstruction of the skullcap removed during decompressive craniectomy (DC). Cranioplasty improves rehabilitation from a motor and cognitive perspective. However, it may increase the possibility of postoperative complications, such as seizures and infections. Timing of cranioplasty is therefore crucial even though literature is controversial. In this study, we compared motor and cognitive effects of early cranioplasty after DC and assess the optimal timing to perform it.

METHODS

A literature research was conducted in PubMed, Web of Science, and Cochrane Library databases. We selected studies including at least one of the following test: Mini-Mental State Examination, Rey Auditory Verbal Learning Test immediate and 30-min delayed recall, Digit Span Test, Glasgow Coma Scale, Glasgow Outcome Scale, Coma Recovery Scale-Revised, Level of Cognitive Functioning Scale, Functional Independence Measure, and Barthel Index.

RESULTS

Six articles and two systematic reviews were included in the present study. Analysis of changes in pre- and postcranioplasty scores showed that an early procedure (within 90 days from decompressive craniectomy) is more effective in improving motor functions (standardized mean difference [SMD] = 0.51 [0.05; 0.97], p-value = 0.03), whereas an early procedure did not significantly improve neither MMSE score (SMD = 0.06 [-0.49; 0.61], p-value = 0.83) nor memory functions (SMD = -0.63 [-0.97; -0.28], p-value < 0.001). No statistical significance emerged when we compared studies according to the timing from DC.

CONCLUSIONS

It is believed that cranioplasty performed from 3 to 6 months after DC may significantly improve both motor and cognitive recovery.

Cranioplasty After Severe Traumatic Brain Injury: Effects of Trauma and Patient Recovery on Cranioplasty Outcome

Background

In patients with severe traumatic brain injury (sTBI) treated with decompressive craniectomy (DC), factors affecting the success of later cranioplasty are poorly known.

Objective

We sought to investigate if injury- and treatment-related factors, and state of recovery could predict the risk of major complications in cranioplasty requiring implant removal, and how these complications affect the outcome.

Methods

A retrospective cohort of 40 patients with DC following sTBI and subsequent cranioplasty was studied. Non-injury-related factors were compared with a reference population of 115 patients with DC due to other conditions.

Results

Outcome assessed 1 day before cranioplasty did not predict major complications leading to implant removal. Successful cranioplasty was associated with better outcome, whereas a major complication attenuates patient recovery: in patients with favorable outcome assessed 1 year after cranioplasty, major complication rate was 7%, while in patients with unfavorable outcome the rate was 42% (p = 0.003). Of patients with traumatic subarachnoid hemorrhage (tSAH) on admission imaging 30% developed a major complication, while none of patients without tSAH had a major complication (p = 0.014). Other imaging findings, age, admission Glasgow Coma Scale, extracranial injuries, length of stay at intensive care unit, cranioplasty materials, and timing of cranioplasty were not associated with major complications.

Conclusion

A successful cranioplasty after sTBI and DC predicts favorable outcome 1 year after cranioplasty, while stage of recovery before cranioplasty does not predict cranioplasty success or failure. tSAH on admission imaging is a major risk factor for a major complication leading to implant removal.

The effect of cranioplasty following decompressive craniectomy on cerebral blood perfusion, neurological, and cognitive outcome

OBJECTIVE

Decompressive craniectomy is an established therapy for refractory intracranial hypertension. Cranioplasty following decompressive craniectomy not only provides protection to the brain along with cosmetic benefits, but also enhances rehabilitation with meaningful functional recovery of potentially reversible cortical and subcortical damaged areas of the affected as well as the contralateral hemisphere. The aim of the study was to assess neurological and cognitive outcome as well as cerebral blood flow after cranioplasty.

METHODS

Thirty-four patients admitted for replacement cranioplasty after decompressive craniectomy for head injury were studied prospectively. Clinical, neurological, and cognitive outcomes were assessed by the Glasgow Outcome Scale (GOS), the Glasgow Coma Scale, and a battery of cognitive tests, respectively. Simultaneously, cerebral blood perfusion was assessed by technetium-99m ethyl cysteinate dimer (99mTc-ECD) brain SPECT imaging 7 days prior to and 3 months after cranioplasty.

RESULTS

Prior to cranioplasty 9 patients (26.5%) had GOS scores of 5 and 25 patients (73.5%) had GOS scores of 4, whereas postcranioplasty all 34 patients (100%) improved to GOS scores of 5. Approximately 35.3%–90.9% patients showed cognitive improvement postcranioplasty in various tests. Also, on comparison with brain SPECT, 94% of patients showed improvement in cerebral perfusion in different lobes.

CONCLUSIONS

Cranioplasty remarkably improves neurological and cognitive outcomes supported by improvement in cerebral blood perfusion.

How Early Can We Perform Cranioplasty for Traumatic Brain injury After Decompressive Craniectomy? A Retrospective Multicenter Study

OBJECTIVE

Decompressive craniectomy (DC) is used to treat intractable intracranial hypertension after severe traumatic brain injury (TBI). Cranioplasty (CP) is typically performed weeks or months later. However, the optimal timing for CP is unknown. We aimed to determine the earliest possible time point for CP.

METHODS

We retrospectively reviewed brain computed tomography images from 159 patients who underwent CP after DC for TBI at 3 hospitals. We determined the earliest possible day for CP by reviewing the resolution of intracranial pressure in serial brain computed tomography images between DC and CP. The early CP group was defined as the group within the earliest possible timing of CP; other cases constituted the late CP group. We compared complications and the Glasgow Outcome Scale scores at 6 months between groups.

RESULTS

The mean initial Glasgow Coma Scale score was 8.33 ± 3.46. The time interval between DC and CP was 94.75 ± 143.98 days. The earliest possible timing for CP was determined to be 34.60 ± 34.36 days after DC. The incidence of complications did not differ significantly between groups, except for ventriculomegaly, which occurred more frequently in the late CP group (P = 0.026). Predictors of good outcome were revision because of infection, preoperative epidural hematoma, early cranioplasty, and no ventriculomegaly after DC.

CONCLUSIONS

CP can be performed at around 34 days after DC for TBI. Ventriculomegaly occurred less frequently and the 6-month Glasgow Outcome Scale score was better in the early CP group than in the late CP group.

Early vs late cranioplasty: what is better?

AIM OF THE STUDY

Cranioplasty is the surgical repair of skull defects, which commonly is performed after traumatic skull injuries due to tumor removal or decompressive craniectomy. Several studies reported improvement in cognitive functions following cranioplasty in patients with severe brain damage. The reasons why exist such clinical improvement is not completely understood, although the increase in cerebrospinal fluid hydrodynamics with the potential improvement of local and global cerebral hemodynamics, blood flow, and metabolism may play a pivotal role. We investigated whether the cranioplasty improved neurological recovery and the whole array of cognitive functions or just some specific domains.

MATERIALS AND METHODS

A total of 30 consecutive brain-injured subjects with craniectomy were enrolled and underwent a structured neuropsychological assessment immediately before the cranioplasty, 1 month after the cranioplasty and 1 year after the surgical procedure.

RESULTS

Our results showed that cranioplasty may facilitate the cognitive recovery, independently from the surgical timing. Particularly, we observed an important cognitive recovery in the period immediately after cranioplasty, while the improvement trend settles after a lapse of time, and the recovery starts to slow down.

CONCLUSIONS

Cranioplasty seems to significantly improve neuropsychological and motor status in the patients with skull defects, independently from cranioplasty timing and patient's clinical status.