3D-printed guide template for cervical stabilization surgery: A case report

Abstract

Introduction

Cervical spine injuries are a growing global public health concern. Management depends on injury severity, with severe cases requiring surgical decompression and stabilization. Emerging technologies such as 3D-printed patient-specific templates offer enhanced accuracy and safety in pedicle screw placement compared to traditional freehand techniques.

Research question

Can 3D-printed patient-specific guide templates improve the safety, efficiency, and outcomes of cervical spine fusion procedures compared to conventional techniques?

Case report

A 62-year-old male with a cervical spinal injury underwent emergency decompression at an external facility. Subsequent imaging revealed iatrogenic instability due to multi-level laminectomies (C3-C6). Preoperative CT data were processed using software (Mimics v14, MeshMixer) to design patient-specific templates, printed with a 3D Ultimaker 2 printer. These sterilized templates were used intraoperatively for navigation, aiding in transpedicular screw placement at C2, C7, and T1 levels, with lateral mass screws placed for C3-C6 using a freehand technique.

Results

Intraoperative fluoroscopy confirmed accurate screw placement with no vertebral artery injury or malposition. Postoperative CT validated precise alignment, and no hematoma or complications were observed. The use of 3D templates reduced operative time and radiation exposure compared to traditional methods.

Discussion

3D-printed templates offer a cost-effective and accessible alternative to robotic systems, enhancing precision and minimizing complications. Literature supports their safety, accuracy, and potential to reduce operative time, blood loss, and radiation exposure.

Conclusion

3D-printed templates represent an effective and innovative tool for improving cervical spine surgery outcomes. Future advancements in 3D-printing technologies could further optimize spinal stabilization and fusion procedures.

Highlights

• •Cervical spinal trauma necessitates immediate and meticulous intervention due to the high risk of spinal cord injury.
• •Eventhough various surgical techniques are available, the high rate of complications like dural tear, arterial injury and screw malposition have prompted efforts to develop new and improved methods.
• •The use of personalized models created with three-dimensional printing technology aims to reduce complication rates.

1. Introduction

In recent years, the incidence of fall-related cervical spine injuries in older adults has been steadily increasing, becoming a significant global public health concern (McCaughey et al., 2016; Güzelküçük et al., 2015). Fractures without substantial displacement can often be managed with external orthoses and immobilization. However, injuries involving ligamentous disruption, severe dislocation, or spinal cord compression typically require surgical decompression and fusion (Joaquim et al., 2013; Azimi et al., 2021).

To achieve effective decompression, multi-segment and wide laminectomies may be necessary. However, disruption of the posterior ligamentous complex following laminectomy increases cervical spine mobility, leading to instability and kyphosis (Mittal et al., 2024; Noh et al., 2022; Jin et al., 2023; Goel et al., 1988; Somay et al., 2022). Various stabilization techniques have been utilized in the management of cervical spine instability (Youmans and Winn Neurological Surgery, 2017). The freehand technique and O-arm-based navigation are commonly used for cervical screw placement. However, screw misplacement can result in serious complications, including vertebral artery or spinal cord injury, which may significantly impact patient outcomes (Mummaneni and Haid, 2005).

To mitigate these risks, many surgeons are exploring innovative techniques that integrate the latest technological advancements. Robot-guided systems enhance accuracy and safety in pedicle screw insertion and size selection, thereby reducing the likelihood of complications (Lieberman et al., 2020). However, these systems remain cost-prohibitive for many surgical centers, particularly those in resource-limited or remote settings.

Over the past few years, three-dimensional (3D) printing has become an invaluable tool in neurosurgery, particularly for surgical planning, intraoperative navigation, and anatomical visualization (Ozgıray et al., 2023; Belvedere et al., 2022; Goffin et al., 2001). 3D-printed template guidance is a readily accessible technique that enhances outcomes in cervical spine fusion procedures compared to conventional approaches. These outcomes are evaluated based on blood loss, screw malposition, fluoroscopy usage, and operative time (Tian et al., 2019).

We present an elderly patient who sustained a cervical distraction injury after a fall from standing height. He had a cervical fracture leading to spinal cord compression and edema, with a preexisting history of cervical stenosis. Following the injury, he underwent decompression surgery at an external medical facility. However, the development of iatrogenic cervical instability necessitated further surgical intervention. Cervical stabilization and fusion were meticulously planned and successfully performed to restore spinal stability.

2. Case report

In our case, a 62-year-old male patient sustained a cervical spinal injury after a fall from standing height. He initially underwent emergency cervical decompression surgery at the facility where the accident occurred. Following this procedure, he was admitted to our clinic. Due to iatrogenic instability caused by four-level cervical laminectomies, a subsequent surgical intervention involving cervical fusion and stabilization was planned.

Preoperative radiologic assessment was performed using computed tomography (CT) and magnetic resonance imaging (MRI). CT scans revealed a laminectomy defect extending from the third cervical vertebra (C3) to the sixth cervical vertebra (C6) (Fig. 1).

Fig. 1.

A) Cervical vertebrae sagittal CT scan showing multiple level laminectomy from cervical third (C3) vertebrae to sixth (C6). B) Cervical vertebrae sagittal MRI scan T2 weighted image. White arrow shows cord edema between C4-5-6 vertebral level.

The CT images were uploaded to the software (Mimics v14, Materialise Corp., Belgium) for processing. Patient-specific models were then generated using MeshMixer software (Autodesk, San Francisco, CA, USA) (Fig. 2). 3D templates were printed using a 3D Ultimaker 2 printer (Ultimaker B.V., Utrecht). Subsequently, the models were sterilized to allow intraoperative use as a navigation tool (Fig. 3).

Fig. 2.

Patient-specific three-dimensional servical vertebrae models and templaetes were created via MeshMixer software.

Fig. 3.

A-B) 3D-printed templates were sterilized with the aim of giving the opportunity to be used intraoperatively as a navigation tool. C-D) Postoperative cervical CT scan axial sections of level C2 and C7 have obtained on surgery day 0.

We placed transpedicular screws in the C2 and C7 vertebrae using a 3D-printed, patient-specific guide. The patient underwent cervical fusion from C2 to T1. Transpedicular screws were inserted at C2, C7, and T1, while lateral mass screws were placed using the freehand technique at the intermediate levels (C3–C6).

Guides enabled the rapid identification of screw entry points and optimal orientation. Intraoperative C-arm fluoroscopy images were obtained after each screw placement to assess localization. Postoperatively, CT scans were performed on the day of surgery (postoperative day 0) to verify accurate screw positioning and evaluate postoperative hematoma (Fig. 3). Using the template, we placed four screws (C2 and C7 bilaterally), all of which were fully contained within the pedicle. No vertebral artery injury was observed. We did not encounter any surgical site infections.

3. Discussion

Cervical trauma can result from either closed or penetrating injuries caused by high- or low-energy mechanisms (Early Management of Cervical Spine, 2020). The incidence of low-energy trauma is not uncommon (McCaughey et al., 2016; Güzelküçük et al., 2015), and such injuries can lead to unstable fractures requiring surgical decompression and stabilization.

Cervical screw fixation is a technically demanding procedure that requires extensive experience and meticulous attention to detail. The traditional freehand technique for pedicle screw placement in spinal surgery can be unreliable and may be associated with varying degrees of complications, including dural tears, arterial injury, and screw malposition (Baghdadi et al., 2013).

Recent research has focused on alternatives to freehand and navigated techniques that provide equal or greater accuracy in screw placement. Many surgeons worldwide have demonstrated the feasibility of 3D-printed patient-specific templates for this purpose. These templates are generated based on preoperative CT scans and fit precisely onto the dorsal bony surface of the targeted vertebrae. Drill holes in the templates guide the entry points and trajectories of screws for each unique pedicle.

Several studies in the literature have demonstrated the accuracy of this technique. In a study contributed to by Farshad et al. a total of 86 screws were inserted, 82 of which (95.3 %) were fully contained within the pedicle. Notably, none of the perforations resulted in neurovascular complications. A cadaveric experiment reported accuracy rates as high as 98.1 %, compared to the freehand technique, which has reported accuracy rates as low as 50 % (Farshad et al., 2022). In a similar biomechanical cadaver study, a total of 115 screws were implanted in 25 patients, with 107 screws (93.1 %) being entirely contained within the pedicle (Yu et al., 2017). Deng et al. placed 48 screws, 46 of which (95.8 %) were fully inserted into the cortex of the pedicle or lamina. The remaining two screws (4.2 %) slightly breached the inner wall of the pedicle, exposing less than half of the screw diameter (Yu et al., 2017). Pijpker et al. implanted 76 screws, all of which were classified as “safe” (100 %) due to the absence of neurovascular injury, facet joint violation, or pedicle wall breach (Deng et al., 2016). However, the majority of clinical studies on this technique have been conducted in Asia and Europe (Farshad et al., 2022; Yu et al., 2017; Deng et al., 2016; Pijpker et al., 2021).

Having drill guide templates beforehand helps surgeons understand the surgical planning more easily. Tailored to the patient's specific anatomy, templates serve as unique educational tools during preoperative planning, particularly for inexperienced surgeons and surgical residents still in training. The preoperative use of templates allows for the trial and adjustment of screw orientation. This oppurtunity is not reachable with any other navigation methods currently.

Robot-assisted techniques offer high accuracy but are not readily accessible to all medical centers. In contrast, the template-assisted fixation method presents a cost-effective alternative that does not require specialized equipment or place additional strain on hospital resources. At our institution, the entire process—from three-dimensional imaging analysis to planning and printing—costs approximately $100. This affordability enhances the feasibility of the technique, particularly in resource-limited settings and hospitals in low-income countries.

The intraoperative use of O-arm/C-arm imaging can be beneficial; however, it carries a significant risk of high radiation exposure for both the surgical team and the patient (Mummaneni and Haid, 2005). Achieving precise screw placement with the freehand technique requires repeated imaging from frontal and lateral perspectives, leading to prolonged operative times, increased intraoperative bleeding, and greater radiation exposure for both patients and surgical staff. Guo et al. reported that the use of 3D-printed templates reduces radiation exposure time to approximately one-fourth of that required by conventional imaging methods (Guo et al., 2017; Liu et al., 2022). Moreover, frequent repositioning of the X-ray machine and repeated entries and exits from the operating room may further increase the risk of surgical site infections.

The precise fit of the template to the dorsal surface of the cervical vertebrae significantly reduced surgery time compared to our previous experience with other navigation systems. Liang et al. demonstrated that the mean placement time per screw, total screw placement time, and blood loss were significantly lower in the 3D-printed template group compared to the freehand group (Liang et al., 2021). Additionally, meta-analyses in larger patient cohorts have reported a reduction in blood loss. We propose that the use of templates may contribute to decreased anesthesia duration, medication usage, blood transfusion requirements, and infection risk.

However, some studies in the literature have found no significant difference in operative time, emphasizing the need for further multicenter studies to provide a more comprehensive evaluation (Farshad et al., 2022).

A considerable amount of time is required to print the templates and plan the trajectory of each screw before surgery. However, future advancements in software and more efficient 3D-printing technologies are expected to reduce the time required for template preparation.

Promising research on 3D-printing applications suggests that 3D-printed osteoconductive biomaterials promote osteointegration and improve spinal fusion outcomes (Driscoll et al., 2020). The success of spinal instrumentation largely depends on achieving solid arthrodesis, driven by strong osseointegration and new bone formation. Future research aims to advance the 3D-printing of biomaterials, such as hydroxyapatite and demineralized bone matrix, for use in spinal implants, with the goal of enhancing fusion success rates safely and effectively (Iqbal et al., 2024).

4. Conclusion

3D-printed guide templates can significantly enhance the accuracy of pedicle screw placement while reducing placement time and associated blood loss. These templates offer a precise, safe, and cost-effective tool for pedicle screw insertion. Future research will focus on developing advanced stabilization and fusion solutions using customized, osteointegrative materials to further improve surgical outcomes.

Informed consent

Written informed consent for the submission of this paper was obtained from the patient.

Additional disclosures

No further relationships or activities that could appear to have influenced the submitted work are reported.

Ethical approval

The patient provided consent for the writing and publication of this case.

Author contributions

All authors significantly contributed to the development of this article and have approved the final version for publication.

Declaration of generative AI in scientific writing

During the presentation of this work the author(s) used the Open AI's Chat GP (Open AI Inc, San Francisco, USA) for spell and grammar checking of the final manuscript. After using this tool the author(s) reviewed and edited the content as needed and take full responsibility fort he content of the publication.

Funding

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Handling Editor: Prof F Kandziora