Clinical study on the application effect of improved polyetheretherketone cranial plate in cranioplasty Open Access

Cranioplasty surgery is a fundamental technique in neurosurgery that aims to repair skull defects resulting from trauma, surgery, or lesions in order to restore the integrity of the cranial structure and safeguard brain tissue function.¹ Over the years, various materials have been used for cranioplasty, including autologous bone, titanium mesh, and polyetheretherketone (PEEK). With the continuous progress in medical technology and material science, the selection and enhancement of cranioplasty materials have emerged as crucial research areas in this field.^2–4 PEEK has gained widespread application in skull repair owing to its outstanding biocompatibility, mechanical strength, and stability. Nevertheless, conventional PEEK materials exhibit certain limitations in clinical settings, necessitating further optimization and enhancement.^5–7 In selecting materials for skull repair, researchers and clinicians must consider a range of factors comprehensively, including biocompatibility, mechanical properties, durability, plasticity, infection resistance, and the capacity to bond with natural bone tissue. While traditional PEEK materials exhibit certain advantages, their surface properties can result in inadequate bonding with surrounding bone tissue, thereby impacting the effectiveness of repair. Additionally, the inherent lack of antibacterial properties in PEEK materials may elevate the risk of complications, particularly in cases where there is a heightened risk of postoperative infection.^8–12 

To address these limitations, numerous researchers have explored various strategies to enhance PEEK materials, including surface coating treatments, structural design optimization, and the incorporation of antibacterial agents.^13–15 In this study, the geometric structure, titanium nail fixation position, and mesh density of the PEEK material were optimized to develop an enhanced version of PEEK material. Specific improvement measures include the following: (1) Optimization of geometric structure: The geometric shape of the PEEK skull plate was redesigned using the finite element mechanics analysis to better adapt to the stress distribution in the skull defect area, and the edge thickness was refined. (2) Improvement of titanium nail fixation position: The titanium nail fixation position was optimized to distribute stress more evenly and reduce the risk of titanium nail breakage during long-term use. (3) Optimization of mesh density: The mesh density of the PEEK material was adjusted to enhance its fusion capability with surrounding bone tissue and minimize the formation of dead space, thereby decreasing the risk of infection and promoting bone tissue healing. (4) Surface treatment and antibacterial coating: The surface of the modified PEEK material underwent special treatment, and a layer of antibacterial coating was applied. This coating not only enhances the antibacterial properties of the material and effectively reduces the incidence of postoperative infection but also improves the biocompatibility of the material, promoting the integration of bone tissue. (5) Customization using 3D printing technology: The integration of 3D printing technology with personalized customization based on the patient’s skull Computed Tomography (CT) data enhances the success rate of the surgery and further increases patient satisfaction.

Despite the growing use of enhanced PEEK materials, there remains a gap in the literature regarding their long-term clinical outcomes, especially in terms of safety, patient satisfaction, and cost-effectiveness. This study aims to explore the impact of enhanced PEEK materials on postoperative complications, patient satisfaction, and medical costs, to fill the gap in the existing literature regarding their long-term clinical outcomes and cost-effectiveness.

This study employed a prospective randomized controlled trial design, involving patients who underwent cranioplasty at our hospital from January 2020 to June 2022. Patients were randomly assigned to either the modified PEEK group or the conventional PEEK group in a 1:1 ratio, with allocation determined by a computer-generated randomization sequence to ensure comparability of baseline characteristics between the two groups. The randomization process was conducted by an independent statistician who was not involved in patient recruitment or clinical decision-making. The allocation sequence was concealed until the moment of assignment to prevent selection bias. Allocation was performed by a separate research assistant, ensuring effective concealment of group assignments. Ethical approval for this study was granted by the Bioethics Committee of Shanghai Tenth People's Hospital (Approval No. SYCM-YJKT-19-0524/02, approved on May 24, 2019).

In this research, rigorous inclusion criteria were established to guarantee the uniformity of the study participants, thus reducing the potential impact of confounding variables on the findings. The inclusion criteria are outlined as follows: (1) Participants should be aged between 15 and 90 years, be of Han nationality, and qualify for surgery related to skull defects. (2) The dimensions of the skull defect must be greater than 3 × 3 cm. (3) A minimum of two months must have passed since the most recent craniectomy, during which vital signs remained stable. (4) The location of the skull defect should be above the tentorium, excluding patients with complex conditions (including those associated with the basal ganglia). (5) All individuals involved must be free of mental disorders and able to engage in postoperative follow-up and assessments.

To maintain the integrity of research data and assess material performance accurately, the following exclusion criteria are established: (1) Individuals with high-risk complications, including hydrocephalus, brain tumors, and intracranial infections, are not included, since these conditions usually require more intricate treatment approaches that might obstruct the evaluation of material characteristics. By excluding such individuals, the emphasis can be placed on improving the essential properties of PEEK materials. (2) Individuals with allergies to two or more medications or foreign substances are also omitted from the study. This measure aims to reduce the possibility of postoperative infections or rejection, ensuring that any detected infections are closely related to the material being studied. (3) Individuals suffering from coagulation disorders, abnormal liver and kidney function, or severe cardiopulmonary issues are excluded because they present a greater risk for intraoperative and postoperative complications, which could hinder the assessment of material performance. (4) Those participating in cranial repair surgery for the first time are included, whereas patients undergoing reoperations are excluded, as reoperations could heighten the risk of infection and complicate the integration of materials.

The 104 enrolled patients underwent cranioplasty with improved PEEK skull plates or conventional PEEK skull plates.

1. During the preoperative preparation stage, the production and customization of repair materials involve three-dimensional reconstruction and finite element analysis of the patient’s CT data. The typical production cycle for these materials is one day. The fabrication of enhanced PEEK materials relies on established computer-aided design and 3D printing technologies, resulting in a production process that is not significantly different from that of conventional PEEK materials. Consequently, the material production cycle does not impede surgical planning and can be conducted concurrently with regular surgical schedules;

2. Routine preoperative examinations: including blood routine, liver and kidney function, electrolytes, myocardial enzyme spectrum, coagulation function, tumor markers, electrocardiogram, lung function, echocardiography, cranial 3D CT scan, and chest CT scan, with detailed records of the results;

3. Signing of the “Surgical Informed Consent.”

1. Anesthesia: Endotracheal intubation general anesthesia, patients with tracheostomy were directly anesthetized through the stoma.

2. Surgical operation: After routine disinfection and draping, a skin incision was made, separating the scalp, galea aponeurotica, and muscle, fully exposing the bone edge; open the package containing the modified PEEK or conventional PEEK material and verify the accuracy of the information provided. Utilize titanium alloy fixation nails to secure the prosthesis to the bone edge. For the modified PEEK material, its geometric structure, the positioning of the titanium nails, and the mesh density have been optimized through finite element mechanical analysis to ensure that the material effectively adapts to the stress distribution in the skull defect area. The edge thickness of the modified PEEK has been reinforced, and the mesh density has been precisely controlled to enhance the integration of the implant with the surrounding bone tissue, thereby reducing the risk of infection and the formation of dead space. After securing the repair, the dura mater is sutured and suspended layer by layer, and a drainage tube is placed to complete the operation.

3. Postoperative management: Closely monitor the patient's vital signs, remove the drainage tube 1–2 days after surgery, provide anti-infection treatment for at least 5 days postoperatively (Although the enhanced PEEK material demonstrates improved anti-infection performance, we opted for a more conservative antibiotic regimen in the initial study, given the complexity of cranial repair surgery and the potential risk of postoperative infection. This decision prioritizes safety, particularly during the early stages of new material application. In the future, as clinical data on the improved PEEK materials accumulate, we will assess the feasibility of reducing the duration of antibiotic use to optimize treatment options), and decide on symptomatic supportive treatment plans based on the condition.

Follow-up was conducted on the first day, six months, one year, and two years postsurgery, recording cranial CT, adverse reactions, and changes in the internal environment.

To guarantee the best possible performance of the enhanced PEEK material during surgical operations, we have meticulously optimized its geometric configuration and mesh density. As shown in Fig. 1, the design of the upgraded PEEK material is depicted. Utilizing finite element mechanics analysis, we have fine-tuned the geometric shape, the position for titanium nail fixation, and the mesh density of the PEEK material. This refinement improves the material's compatibility with the surrounding bone tissue, alleviates stress concentration, and optimizes the placement of the titanium nail fixation, significantly decreasing the likelihood of material fracture. Furthermore, the heightened mesh density facilitates better biocompatibility and reduces the occurrence of dead space, thereby lowering the chances of postoperative infection.

The main evaluation indicators of this study included:

1. Incidence of postoperative adverse reactions: Recording and analyzing the occurrence of various complications in the two groups;

2. Patient satisfaction: Assessed using the SF-36 quality of life scale;

3. Medical costs: Comparing the economic burden of the two groups through patient hospitalization costs;

4. Cerebral blood flow (CBF) perfusion: Evaluating changes in postoperative cerebral blood flow and cerebral blood volume (CBV) through CT imaging;

5. Survival time: Recording the survival status and causes of death in the two groups;

6. Evaluation of implant stability and bone healing: Implant stability and bone healing were objectively assessed through periodic postoperative CT scans. Specifically, implant stability was evaluated by measuring positional shifts and detecting any loosening of fixation pins. Imaging software was employed to accurately assess the relative positions of the implant and surrounding bone tissue, with implant stability defined as a displacement of less than 2 mm between follow-up time points. Concurrently, CT images were utilized to evaluate the bonding status between the titanium nail and the surrounding bone tissue; the presence of a low-density shadow around the titanium nail indicates a potential risk of loosening. Bone healing was primarily assessed through the formation of a bone bridge and measurements of bone density. CT images were scrutinized for the presence of a continuous bone bridge at the implant's edge, and the bone density measurement function of CT was used to quantify changes in the density of the bone tissue surrounding the implant. An increase in density that approaches that of normal bone tissue is indicative of successful bone healing.

Data analysis was performed using R software version 3.4. Continuous variables were compared between groups using an independent t-test, while categorical variables were analyzed using the chi-square test or Fisher’s exact test for small sample sizes. A p-value of less than 0.05 was considered statistically significant for all analyses.

This study comprised 104 patients, who were divided into two groups: improved PEEK and conventional PEEK, each group consisting of 52 cases. The baseline clinical data of the patients can be found in Table I. No statistically significant differences were observed in gender, age, cause of skull defect, and defect area between the two groups (P > 0.05), suggesting similar baseline characteristics among the groups.

The analysis of statistics in this study indicated (see Table II) that the overall rate of postoperative adverse reactions in the modified PEEK group was 28.85%, which is considerably lower than the 50.00% recorded for the conventional PEEK group (P = 0.027). This finding highlights the safety benefits of utilizing modified PEEK materials in postsurgical settings. In detail, the infection rate after surgery in the modified PEEK group was 3.85%. Although this figure did not display a statistically significant difference when compared to the 9.62% found in the conventional PEEK group (P = 0.240), it hints that enhancing mesh density and geometric design could potentially lessen the likelihood of postoperative infections. In terms of bleeding, the modified PEEK group experienced a rate of 1.92%, which is significantly lower than the 13.46% observed in the conventional PEEK group (P = 0.027). All bleeding cases in the modified PEEK group were classified as subdural hemorrhages, while the conventional PEEK group had six occurrences of epidural hemorrhage and one instance of submembranous hemorrhage (total bleeding rate of 13.46%). Furthermore, concerning epilepsy, no sustained seizures were recorded in the modified PEEK group, with all incidents being single seizures; in contrast, the conventional PEEK group reported two cases of sustained seizures. The modified PEEK group showed no occurrences of implant fractures, while the conventional PEEK group had three cases, accounting for 5.77% of implant fractures. This issue of implant fractures was particularly significant during long-term follow-ups, as demonstrated in Fig. 2, where a patient developed a fracture with edge warping two years after undergoing titanium plate repair. This evidence further emphasizes that traditional materials may present a higher risk of fracture with prolonged use, whereas modified PEEK materials offer notable benefits in terms of implant stability and longevity. These results indicate that the modified PEEK material significantly reduces postoperative bleeding and seizures while enhancing implant stability, thereby supporting its potential value in clinical applications. For specific incidence rates, refer to Table II.

To provide a clearer understanding of the benefits offered by modified PEEK materials in reducing fractures of titanium nails, Figs. 3 and 4 display the stress distribution patterns for both conventional and modified PEEK materials. Through finite element analysis, it is observed that the stress distribution in the enhanced PEEK material is more even, successfully preventing stress concentration at the edges. This improvement plays a significant role in the stability of the material during extended use, thus further lowering the chances of titanium nail failure.

The results of the study indicated that the physical function, mental health, and social function scores of patients in the modified PEEK group were significantly higher than those in the conventional PEEK group, both six months and two years postsurgery (P < 0.05). Specifically, the physiological function score for the modified PEEK group was 85.25 ± 7.82, compared to 78.42 ± 8.38 for the conventional PEEK group (P = 0.001). Regarding mental health, the modified PEEK group achieved a score of 80.12 ± 6.96, while the conventional PEEK group scored 72.36 ± 7.18 (P = 0.002). For social function, the modified PEEK group scored 82.57 ± 7.52, significantly surpassing the conventional PEEK group, which had a score of 74.83 ± 7.65 (P = 0.003). Detailed scores can be found in Table III.

These findings suggest that the modified PEEK material not only demonstrates superior performance in terms of postoperative safety but also significantly enhances patients’ quality of life and satisfaction. The benefits observed in the modified PEEK group, including a reduction in postoperative complications and an acceleration of recovery, may be key factors contributing to these differences.

The total medical costs during hospitalization for both groups encompassed surgery costs, hospitalization costs, and medication costs. The average medical cost for the improved PEEK group was ¥ 144 600, compared to ¥ 127 400 for the conventional PEEK group, showing a significant difference between the two groups (P < 0.05). Detailed costs can be found in Table IV. In the modified PEEK group, the duration of the hospital stay was notably longer, potentially due to the heightened requirement for postoperative monitoring and assessment of the new material. Future research will investigate the specific factors contributing to extended hospital stays and their implications for overall healthcare costs.

CT imaging was utilized to evaluate the effectiveness of skull repair in both patient groups within a timeframe of six months to two years following surgery. The findings revealed that the group using modified PEEK showed a considerable advantage in implant position stability and bone healing when compared to the conventional PEEK group (refer to Table V).

The detailed outcomes of the imaging assessments are depicted in Figs. 5 and 6. In Fig. 5, the CT scans of the modified PEEK group taken six months after surgery show that the position of the implant is stable, and the bone bridge appears to be well-developed, reflecting an effective bone healing process. Conversely, Fig. 6 indicates that although the implant position in the conventional PEEK group remained largely unchanged, the formation of the bone bridge occurred at a slower rate, resulting in less effective bone healing when compared to the modified PEEK group.

This study examined changes in key indicators such as CBF, CBV, and mean transit time (MTT) before and after surgery (at one month, six months, one year, and two years) in both the improved PEEK and conventional PEEK groups using cerebral perfusion CT or Magnetic Resonance Imaging techniques. The results are summarized in Table VI. Prior to surgery, there were no significant differences in CBF, CBV, and MTT values between the two groups. One month postsurgery, both groups showed an increase in CBF, although the difference was not statistically significant (P > 0.05). Similar trends were observed in changes in CBV and MTT. At six months and one year after surgery, both groups exhibited consistent patterns of recovery and stabilization in CBF, CBV, and MTT, with the improved PEEK group showing slightly higher CBF values compared to the conventional PEEK group, albeit not reaching statistical significance (P > 0.05). By the two-year mark, both groups demonstrated improvements in CBF, CBV, and MTT compared to presurgery levels, indicating a positive impact of cranioplasty on cerebral blood flow perfusion. No statistically significant differences were found between the two groups in these indicators (P > 0.05), suggesting similar long-term effects of the two materials.

PEEK materials are commonly utilized in cranioplasty for their exceptional biocompatibility, mechanical strength, and stability.^16,17 Recent advancements in PEEK materials have resulted in enhanced performance through surface coating treatments, structural design optimizations, and the incorporation of antibacterial components.¹⁸ These enhancements have demonstrated improved clinical outcomes such as decreased postoperative infection risks, enhanced bone tissue bonding, and increased mechanical stability.¹⁹ This study aimed to evaluate the clinical effect of enhanced PEEK skull plates in cranioplasty by analyzing data from 104 patients. The analysis compared the differences in postoperative adverse reaction rates, patient satisfaction, medical costs, and cerebral blood perfusion between the modified PEEK group and the conventional PEEK group. The results indicated that the incidence of postoperative adverse reactions in the modified PEEK group was significantly lower than in the conventional PEEK group (28.85% vs 50.00%, P = 0.027). The reduced incidence of postoperative complications may be attributed to several factors, notably improvements in surgical techniques and the introduction of new materials. It is important to emphasize that the decrease in postoperative complications likely results from a combination of enhanced surgical techniques and the utilization of innovative materials. To maintain consistency and high quality in surgical operations, all procedures were performed by a well-established and technically proficient team of surgeons. The main adverse reactions observed included postoperative infection, bleeding, epilepsy, and implant breakage. The enhanced PEEK material effectively reduces the likelihood of postoperative complications by improving its mechanical characteristics and biocompatibility throughout the design and production stages. In particular, modified PEEK redistributes stress on the skull plate by augmenting the thickness at the edges of the material and fine-tuning the placement of titanium nails, which in turn minimizes the chances of both titanium nail failure and material degradation. Results from finite element analysis suggest that this optimization significantly decreases the risk of postoperative bleeding by ensuring a more even distribution of mechanical forces across the skull plate, thus helping to avert damage to the periosteum and the development of subdural hematomas resulting from over-concentrated stress. Additionally, the refined mesh density design enhances the adhesive strength between the material and adjacent bone tissue, which lowers the chances of postoperative infections and, as a result, reduces the occurrence of subsequent epileptic seizures. Overall, these advancements allow modified PEEK to showcase improved biocompatibility and mechanical resilience. References in the literature^11,16,18 indicate that by optimizing the geometry of the material and the positioning of fixation points, problems related to implant fractures and localized stress concentrations can be effectively alleviated, thereby decreasing the risk of complications. Consequently, we propose that the effectiveness of modified PEEK materials in mitigating postoperative complications, including bleeding, seizures, and implant fractures, arises from a combination of several contributing factors.

The results of the SF-36 quality of life scale assessment revealed that the group using improved PEEK materials exhibited significantly higher scores in physical function, mental health, and social function at both six months and two years postsurgery when compared to the conventional PEEK group (P < 0.05). This indicates that the enhanced PEEK materials offer not only physiological benefits but also contribute to notable improvements in patients’ psychological well-being and social adaptability, ultimately enhancing their overall quality of life. This phenomenon may be attributed to several factors. First, the optimized design of the enhanced PEEK material contributes to a reduction in postoperative adverse reactions, particularly in terms of minimizing infection rates and enhancing implant stability. These improvements may, in turn, positively influence the patient's physiological function and mental health. However, it is essential to consider potential biases within the study, such as patients’ heightened expectations regarding the new material or the favorable attitudes of healthcare workers toward the improved material, which may have shaped patients’ subjective evaluations. To ascertain whether these enhancements reflect genuine long-term effects rather than mere short-term psychological comfort, we focused on the outcomes observed after a two-year follow-up. While the modified PEEK group continued to report higher quality of life scores at this follow-up, it is plausible that the initial psychological benefits may diminish over time. Consequently, the observed improvements during this period are more likely attributed to the objective advantages of the material, such as enhanced bone healing and stability. Future research should aim to mitigate potential biases through a blinded study design and extended follow-up periods to confirm the sustainability of these improvements.

When comparing the total medical costs of the improved PEEK group and the conventional PEEK group, it was found that the total medical costs of the improved PEEK group were higher (¥ 144 600 ± 21 200 vs ¥ 127 400 ± 20 100, P < 0.05). Despite the higher initial cost of improved PEEK materials, their potential to reduce postoperative adverse reactions and enhance patient satisfaction may lead to long-term economic advantages. By decreasing postoperative complications, there is a potential reduction in subsequent treatment and hospitalization costs, ultimately alleviating the financial burden on patients and reducing the utilization of social resources. However, a comprehensive long-term economic benefit assessment was not performed in this study. Future research should include a detailed cost-effectiveness analysis to evaluate whether the higher initial costs of enhanced PEEK materials are offset by reductions in subsequent treatment costs, such as those due to reoperations and prolonged hospital stays. This will help provide a more comprehensive understanding of the economic impact of enhanced PEEK materials and justify their use in clinical practice. This aligns with the findings of Thimukonda Jegadeesan et al.,³ who also concluded that superior materials, despite their higher upfront costs, offer long-term economic benefits by reducing postoperative complications and increasing patient satisfaction.

Examination results revealed that the enhanced PEEK group exhibited superior implant stability and bone healing at six months and two years postsurgery in comparison to the traditional PEEK group. This suggests that advancements in PEEK materials have been fine-tuned for improved biomechanical performance, effectively catering to the physiological requirements of patients and delivering long-lasting reparative effects. The study of Zhao et al.⁴ further corroborates this finding, demonstrating that enhanced PEEK materials significantly bolstered implant stability and bone healing via surface coating treatment and structural optimization.

The analysis of cerebral blood flow perfusion showed no significant differences in CBF, CBV, and MTT values between the two groups before surgery and at each postoperative time point (P > 0.05). This suggests that enhanced PEEK materials have similar effects to traditional PEEK materials in enhancing cerebral blood flow perfusion, which aligns with the findings of Dondani et al.¹⁹ 

Other clinical advantages of enhanced PEEK materials establish them as a robust option for cranioplasty surgery. The advancements in mechanical properties and biocompatibility decrease the occurrence of postoperative complications. Anderson et al.²⁰ verified that upgraded PEEK materials exhibit greater stability and reliability over the long term, particularly in reducing complications like postoperative infection and bleeding. Furthermore, enhanced PEEK materials promote better bonding with surrounding bone tissue through surface coating treatments and optimized structural designs, ultimately improving implant stability and bone healing effects. Imaging examination results from this study demonstrated that the enhanced PEEK group displayed superior implant stability and bone healing at six months and two years postsurgery compared to the conventional PEEK group. Zhao et al.⁴ also corroborated this finding, indicating that the biomechanical performance optimization of enhanced PEEK materials significantly improved stability and durability postimplantation, better meeting patients’ physiological requirements and delivering long-lasting stable repair effects. Ultimately, the substantial clinical benefits of enhanced PEEK materials in reducing postoperative complications, enhancing patient satisfaction, and optimizing biomechanical performance position them as the preferred materials for cranioplasty surgery.^21–25 These findings align with previous research outcomes, further validating the efficacy and dependability of enhanced PEEK materials in clinical settings.

Future research should delve into the application effects of enhanced PEEK materials across diverse patient demographics. This includes conducting group studies on individuals of varying ages, genders, and types of skull defects to assess the suitability of upgraded PEEK materials in these specific cohorts. Furthermore, integrating extended follow-up data can offer a more thorough assessment of the long-term implications and safety of improved PEEK materials, with a particular emphasis on sustained stability, implant durability, and their ongoing influence on patients’ quality of life.^26–28 

The enhanced PEEK skull plate offers notable clinical benefits in cranioplasty surgery. The incidence of postoperative adverse reactions in the enhanced PEEK group is significantly lower compared to the conventional PEEK group, leading to better implant stability and bone healing at six months and two years postsurgery. Despite the higher total medical costs associated with enhanced PEEK materials, their advantages in reducing postoperative complications and enhancing patient satisfaction and quality of life result in long-term economic benefits. Therefore, enhanced PEEK materials demonstrate superior safety and effectiveness in cranioplasty surgery, making them an optimal choice for repair materials. Future research should delve deeper into their application effects and long-term safety across diverse patient populations.

Although this research has initially indicated the benefits of modified PEEK materials for skull reconstruction, additional studies are required. Future research should concentrate on the following areas: (1) Potential applications for various patient demographics: A clinical appraisal involving higher-risk groups (including individuals with hydrocephalus or intricate injuries) is necessary to confirm the material's safety and effectiveness in different pathological settings. (2) Gathering long-term follow-up information: It is crucial to prolong the follow-up duration to evaluate the material's stability, effectiveness in bone healing, and resistance to infection during extended usage, as well as to monitor its lasting influence on the quality of life for patients. (3) Evaluation of economic benefits: A thorough investigation into the long-term economic advantages is essential, especially regarding savings from lowered rates of reoperations, reduced hospital stays, and fewer complications. Through additional research, the enhanced PEEK material can be advocated for a wider array of clinical applications, its application strategies can be refined, and patient outcomes and quality of life can be improved.

The paper is supported by the following funding projects: Shanghai Municipal Health Commission General Project: Application Research of Finite Element Mechanics Technology Improvement in Skull Repair (Grant No. 201940126); Project of Shanghai Chongming Science and Technology Commission: Application of machine learning in computed tomography for prognosis of traumatic brain injury (Grant No. CKY2020-28); Project of Shanghai Chongming Science and Technology Commission: Study on the Value of Improved Machine Learning Model in Predicting the Prognosis of Emergency Elderly Traumatic Brain Injury (Grant No. CKY2021-26).

The authors have no conflicts to disclose.

The study was approved by the Bioethics Committee of Shanghai Tenth People’s Hospital (No. SYCM-YJKT-19-0524/02) and was conducted according to the Declaration of Helsinki. All participants were informed in detail about this research and gave their written consent.

Jiajun Qin and Fei Xue contributed equally to this work.

Jiajun Qin: Conceptualization (lead); Data curation (lead); Formal analysis (lead); Writing – original draft (lead). Fei Xue: Conceptualization (lead); Data curation (lead); Formal analysis (lead); Writing – original draft (lead). Jin Fu: Conceptualization (equal); Data curation (equal); Formal analysis (equal); Writing – review & editing (equal). Jiping Sun: Conceptualization (equal); Data curation (equal); Formal analysis (equal); Writing – review & editing (equal).

The data that support the findings of this study are available from the corresponding author upon reasonable request.