Abstract
Background Cortical bone trajectory (CBT) screw fixation has emerged as a promising alternative to traditional pedicle screw techniques, particularly for patients with compromised bone quality. The higher technical demands of CBT have driven interest in patient-specific instrumentation (PSI) to improve screw placement accuracy and safety. Despite rapid clinical adoption, the evidence supporting PSI in CBT remains limited. This study aimed to assess the safety and effectiveness of PSI with CBT screws.
Methods A systematic review was conducted following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. PubMed and Embase were searched for articles published before July 2025 evaluating PSI or custom 3D-printed guides for CBT screws. Eligible studies included cadaveric and clinical designs reporting on accuracy, safety, or clinical outcomes. Risk of bias was assessed using validated tools. Data were synthesized narratively and summarized descriptively.
Results Eighteen studies, 7 cadaveric and 11 clinical, met our inclusion criteria. Clinical studies included 620 patients and more than 2800 screws. Across study types, PSI-guided CBT screw placement demonstrated high accuracy, with screw containment rates generally above 90% and breach rates below 4%. Comparative studies showed PSI significantly lowered breach rates compared with freehand techniques. Clinical studies reported low complication and revision rates, with favorable outcomes for pain, neurological status, and fusion. PSI was especially beneficial in complex anatomy and for novice surgeons by reducing operative time and radiation exposure.
Conclusions This review has limitations. Most studies were small, single-center, or case reports with heterogeneous patient populations and limited samples, reducing generalizability and increasing bias. PSI and 3D-printed guides for CBT screw fixation consistently improve placement accuracy and safety. PSI may help democratize access to technically demanding CBT fixation and standardize outcomes.
Clinical Relevance PSI may offer decreased operative time and reduce radiation exposure
Level of Evidence 3.
Introduction
Spinal fusion remains a key operation for spinal disorders, used in degenerative disc disease, spondylolisthesis, deformity, and trauma. Its goal is stable, aligned, and pain relief through solid osseous fusion.1 Achieving that fusion depends on instrumentation: pedicle screws (PSs) are crucial, providing immediate stability and supporting bone healing.1,2 Accuracy is crucial here; mispositioned screws can cause neurovascular injury, lead to construct failure, or necessitate revision surgery. These risks are well documented in recent series.3,4
PS fixation is the gold standard, offering 3-column fixation and proven long-term success.1,5,6 However, it has trade-offs, often requiring wide dissection, and the cancellous corridor is less reliable in osteoporosis, leading to screw loosening, implant failure, and reoperations.7–12 Even in healthy bone, cortical breaches can cause nerve or vascular injuries.1,13 PS also risks violating the superior articulating facet.14 The cortical bone trajectory (CBT), introduced by Santoni et al, addresses these issues;15 it uses a smaller screw angled mediolaterally and caudocephalad to engage denser cortical bone,7 increasing contact, reducing soft tissue disruption, and lowering fracture risk.
Biomechanical studies show that CBT screws have higher insertional torque, superior pullout strength, and similar or better resistance to flexion and extension forces compared with traditional PS fixation.1,2,4,16 Clinically, CBT fixation results in less blood loss, smaller skin incisions, and shorter hospital stays.4,5,17 These benefits, however, come with a cost, as the CBT pathway is narrow and unforgiving. A few millimeters or degrees off trajectory can produce a cortical breach. In this setting, “accuracy” is the clinical determinant of safety, directly tied to risks of neurologic deficit, vascular injury, and construct compromise.1,3,4,18 The margin for error is slimmer than with standard PS.
Several technologies have been deployed to mitigate this risk. Navigation and robotics improve accuracy but require capital investment and infrastructure not available everywhere.19 Patient-specific instrumentation (PSI) is an emerging alternative. It uses preoperative imaging and computer modeling to create 3D-printed templates that match the patient’s anatomy.20 These guides fit over the lamina, facets, or spinous process and direct the drill into a set CBT path.21,22 Though widely used in joint arthroplasty and tumor resections, 23–26 PSI’s application to CBT is a newer extension.
Clinical interest has grown rapidly. Small series and cadaveric studies show promising accuracy, but systematic reviews to date have generally grouped PSI with navigation or robotics, or they focus on traditional PS fixation.4,5,13 Few have taken a CBT-specific view, and even fewer have analyzed PSI separately. This leaves a clear gap: how reliably do patient-specific guides improve accuracy, reduce breach, and affect outcomes when CBT screws are used?
We systematically reviewed the published literature on PSI for CBT fixation, focusing on screw accuracy, breach rates, and reported clinical outcomes. By doing so, we ask a practical question for today’s spine surgeon: can patient-specific 3D-printed guides truly address the accuracy concern in CBT and make this technique safer and more accessible in daily practice?
Methods
Registration and Reporting
This systematic review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines (Figure).27 A protocol was prospectively registered in PROSPERO (CRD420251108494).
PRISMA Flow Diagram of Study Selection for Patient-Specific Instrumentation in Cortical Bone Trajectory Screw Placement. CBT, cortical bone trajectory; PSI, patient-specific instrumentation.
Search Strategy
PubMed and Embase were searched for all articles published prior to July 2025. Both free-text terms and MeSH headings were combined. Key phrases included “patient-specific instrumentation,” “patient-specific guide,” “custom drill guide,” “3D printed guide,” “template,” “cortical bone trajectory,” and “CBT screw.”
Inclusion and Exclusion Criteria
We included studies evaluating PSI or custom 3D-printed guides/templates for CBT screw placement. Eligible designs ranged from cadaveric to clinical reports—case reports, case series, and retrospective or prospective cohorts—if they reported accuracy, safety, or other clinical/technical outcomes.
Studies were excluded if they did not involve CBT screws, did not use PSI or custom guides, or were review articles, expert opinion pieces, or conference abstracts without original data.
Study Selection and Screening
Two reviewers independently screened titles and abstracts. Full texts were retrieved for potentially eligible articles. Disagreements were resolved by discussion; if consensus was not reached, a third reviewer was consulted. The selection process is summarized in a PRISMA flow diagram (Figure).
Data Extraction
From each study, we collected publication details; study design; sample size (patients, specimens, or total screws); mean age; spinal level(s) treated; details of the PSI system or guide; comparator group, if present; accuracy (as % or grade); deviation from planned trajectory (millimeter or degrees); screw-related or procedural complications; reported clinical outcomes; and duration of follow-up.
Risk of Bias Assessment
We applied validated tools matched to study type (Table 1). The MINORS instrument was used for nonrandomized clinical studies, and a custom checklist, adapted from prior reviews, for cadaveric and biomechanical work. Case reports were assessed with the JBI Critical Appraisal Checklist.28–30 Purely digital or modeling studies were described narratively.
Risk of bias assessment.
Overall Quality
Most studies had moderate-to-high methodological quality, with 7 cadaveric tests scoring 13 to 14/16 on MINORS, though they lacked blinded assessments and formal sample size calculations. The case report met all JBI criteria.
Noncomparative case series (n = 4) scored 11 to 12/16 with limitations such as retrospective data and no blinding. Comparative cohorts (n = 4) scored 16 to 21/24 on MINORS, sharing similar issues. A mixed digital/clinical study showed high transparency but lacked blinding and validation.
In summary, the main bias sources were a lack of blinding and no sample size justification. However, all studies reported primary outcomes related to PSI-guided CBT screw placement.
Data Synthesis
A narrative synthesis was conducted, and the results were organized by study type, with descriptive statistics (means and proportions) reported.
Results
Study Characteristics
Eighteen studies met the inclusion criteria (Table 2), encompassing cadaveric models, case reports, case series, retrospective cohorts, and prospective cohorts. Of the studies evaluating PSI for CBT screw placement, 7 were cadaveric studies21,31–36 and 11 were clinical studies involving 620 patients and more than 2800 screws.3,19,21,22,38–40,42–44 Most clinical studies used the MySpine MC (Medacta) system. Outcomes assessed included screw accuracy, breach rates, technical complications, and clinical endpoints such as pain reduction, neurological improvement, fusion rates, and reoperation. Follow-up periods ranged from immediate postoperative status to more than 2 years.
Study findings.
Cadaveric Studies: Accuracy and Technical Outcomes
All 7 cadaveric studies demonstrated high accuracy for PSI-guided CBT screw placement, with accuracy rates ranging from 82.5% to 100% and the vast majority of screws classified as grade 0 or I.21,31–36 Mean deviations from the planned trajectory were typically less than 1 mm: Kim et al and Shi et al reported mean deviations of 0.94 ± 0.42 mm and less than 1 mm, respectively, while Peng et al found entry point deviations between 0.44 and 0.57 mm and midpoint deviations of 0.54 to 0.82 mm in cervical models.21,32 Jarvers et al noted deviations of less than 1 mm and 2° with 98% of screws fully contained using MySpine guides.31 Zhao et al reported 82.5% grade 0, 12.5% grade 1, and 5% grade 2 screws using a double-trajectory PSI template, while only 1 grade III deviation was observed out of 40 screws in the study by Shi et al.33,36 In the sole comparative cadaveric study, Wang et al found that PSI reduced breach rates relative to freehand CBT screw placement: 3.3% medial/lateral and 5.0% superior/inferior breaches in the PSI group vs 13.3% and 18.3% in the freehand group.35 Zhao et al also showed no significant difference between pre- and postoperative sagittal and axial angles, confirming precision in screw placement.36
Biomechanical and Technical Outcomes
Biomechanical analysis indicated that PSI-guided CBT screws achieved high insertion torque and reproducibility, while cement-augmented screws exhibited the greatest pullout strength. However, CBT screws placed with PSI outperformed nonaugmented traditional screws.31 Kim et al and Peng et al found that screws placed with 3D-printed templates showed strong fixation and minimal deviation, particularly in CBT0.7 constructs.21,32 Shi et al and Shi et al confirmed that improved guide design further increased the reproducibility of screw paths and cortical purchase, both in cadaveric and 3D-printed spine models.33,34 Wang et al reported that template-guided CBT screws had fewer wall breaches and more optimal (zone II) placements than freehand screws.35 Zhao et al validated a double-trajectory approach, achieving 82.5% grade 0 placement and confirming containment within cortical bone.36
Technical insights from these studies underscore the importance of guide stability, surface conformity, and ergonomic fit. For example, customizing the contact surface to the spinous process, lamina, and facet contours improved alignment during drilling.33,35,36 Dual-trajectory (CBT + traditional trajectory) and novel CBT designs further enhanced guide versatility and accuracy in complex anatomical regions.2,36
Clinical Studies: Accuracy, Safety, and Clinical Outcomes
The 11 clinical studies—including case reports, series, and both retrospective and prospective cohorts—reported consistently high screw containment rates (91%–100%) and low breach rates, typically below 4%.3,19,21,22,38–40,42–44 In small series, Kim and Marengo et al found 100% screw containment without breach.21,38 Larger series by Marou et al and He et al documented 91%–97.4% grade 0/A placements, with only 2% and 4% of screws exceeding 2 mm breach.39,40 Comparative studies similarly favored PSI groups: Matsukawa et al and Matsukawa et al reported 97.5% to 97.7% accuracy for PSI vs 82.1% for freehand screws; Di Perna et al found significantly higher safe placement rates in PSI groups (96% vs 88.9%, respectively), with minimal grade 2 breaches.19,22,43
No serious neurological complications or implant-related revisions due to screw misplacement were reported in any clinical study. Postoperative CT validated placement accuracy across most studies.
Clinical Outcomes (Pain, Function, Fusion, Complications, and Revision)
Favorable clinical outcomes were consistently reported with PSI-guided CBT screw placement. Case reports and small series described marked pain relief and functional improvement.23,43 In larger cohorts, improvements in the visual analog scale, Oswestry Disability Index, and Japanese Orthopedic Association scores were observed.22,40 Fusion rates were high, with several studies reporting 100% fusion.22,40 Most complications were nonneurological and infrequent, including wound infections and dural tears, all resolving without long-term deficit.42 Revision procedures were rare, only noted for cage subsidence, infection, or adjacent segment disease, with frequencies ranging from 0 to 4 cases.
Workflow, Learning Curve, and Template Reliability
Workflow implementation was generally seamless. PSI guides significantly reduced operative time and fluoroscopy usage in multiple studies.19,22,42,43 Template reliability was high. Marengo et al reported no guide failures, and Zhao et al confirmed all screws were placed as planned.36,38 Novice users achieved high accuracy rapidly, with Marou et al documenting an improvement from 91% to 97% accuracy after just 10 cases, and Fujita et al showing similar breach rates between early and late screws placed by CBT-naïve surgeons.3,39
Comparative and Unique Applications
Multiple studies directly compared PSI with free hand, navigation, or robotics, consistently finding higher accuracy, fewer breaches, and reduced radiation exposure with PSI.19,32,35,43 For instance, Di Perna et al reported a 96% “in-cone” rate with PSI compared with 88.9% for free hand, and Matsukawa et al found 97.7% vs 82.1% accuracy in PSI and freehand cohorts, respectively.19,43
PSI was successfully applied in complex populations, including patients with osteoporosis, spinal deformity, and revision or ASD.31,39–41 Technical modifications—such as modified CBT paths, dual-trajectory placement, and improved guide design—facilitated safe, accurate screw placement in these challenging settings.32,33,36,44
In summary, PSI-guided CBT screw placement demonstrated reproducibly high accuracy and safety across study designs, with particular advantages in complex anatomy and among novice surgeons.3,19,21,22,31,43
Discussion
The growing literature has explored improving CBT screw placement safety and accuracy via navigation, robotics, and freehand methods. Reviews indicate that robotic and navigated approaches enhance accuracy and reduce breaches; however, they do not specify PSI’s role.45 Image-guided neuronavigation has been described as an increasingly adopted adjunct in CBT surgery, but patient-specific guides are often grouped with other technologies.46 Biomechanical and technical reviews focus on surgical technique rather than on the performance of PSI. Thus, while the literature affirms the value of advanced guidance systems, there remains a lack of dedicated, systematic evaluation of PSI in CBT—a gap this review directly addresses.
This review evaluated 18 studies—cadaveric, clinical, and comparative—with more than 2800 screws placed using PSI for CBT. PSI-guided placement had high accuracy: most screw containment rates exceeded 90%, and breach rates were often below 4%. In cadaveric models, accuracy ranged from 82.5% to 100%, with most mean deviations from planned trajectory under 1 mm.21,31–36 Comparative studies showed that PSI reduced breach rates relative to freehand CBT. Clinical data mirrored these findings: large cohorts confirmed PSI’s superiority or noninferiority to freehand approaches, with accuracy rates of 96% to 98% and breach rates usually under 2%.3,19,22,43 Imaging consistently confirmed accurate screw placement, and clinical endpoints—including pain reduction, neurological function, and high fusion rates—were favorable. Serious neurological or implant-related complications were rare, and revisions were infrequent. Notably, workflow analyses revealed that PSI not only reduced operative time and radiation exposure but also allowed high accuracy for less experienced or CBT-naïve surgeons.3,39 Template reliability was high, with no reported guide failures in the prospective series. PSI was particularly valuable in complex cases such as revision surgery, osteoporosis, and spinal deformity.
Our findings both align with and extend the current literature on PSI and 3D-printed guides for spinal instrumentation. Prior studies have reported that PSI improves first-pass accuracy, reduces operative time and radiation, and is associated with minimal neurological complications, even in patients with severe deformity or challenging anatomy.47–49 Our review confirms these advantages specifically for CBT screws, a technically demanding trajectory. Across more than 2800 screws, PSI achieved reproducibly high accuracy and safety—comparable to, or exceeding, other advanced technologies. Importantly, our synthesis demonstrates that these benefits persist across levels of surgeon experience and extend to complex cases such as osteoporosis, spinal deformity, and revision surgery. Notably, some practical challenges were also corroborated: PSI often requires full bony exposure, can incur higher upfront costs, and may necessitate more preoperative planning—factors that have also been reported in prior studies.47,49 Another consideration is the evaluation of adequate decompression. In CBT, once posterior instrumentation is locked, surgeons may not be able to confirm complete decompression; dura is visible, but the nerve roots may be obstructed from view. This assessment difficulty can largely be mitigated by experienced surgeons; therefore, novice surgeons should be wary of this potential obstacle.
The need for more preoperative planning makes PSI unreliable in urgent scenarios. PSI guides are made by reconstructing 3D models from CT images, designing drill guides with software, overlaying them, and then 3D printing the final models. A 2019 study estimated this preoperative preparation at 10 to 12 hours per patient.47 In emergency situations, where time can be critical in determining life or permanent neurological damage, PSI guides are not ideal and should be avoided in favor of traditional methods. Nevertheless, in elective cases, the benefits of PSI generally outweigh the increased preoperative planning requirement.
Other shortcomings of PSI include logistical issues that our review does not directly address, which may be mitigated through increased adoption—a stance we support. Beyond the initial cost of large medical-grade 3D printers, guide production costs vary greatly. Prices can range from $175 to $5400 per unit and greatly depend on the printing materials used.50 Some options include resins, polymers, polyvinyl chloride, titanium, stainless steel, and polyamide. Notably, polymer-based models can cost up to $2500, substantially higher than alternative, lower-cost materials with similar functionality.51 Judicious selection of printing materials, especially when guides are meant to be single use, can help to greatly reduce costs. Last, wider adoption and reduced operative times will also help lower costs, making these guides more accessible to broader patient communities.
Overall, PSI for CBT screws improves clinical practice by increasing procedural consistency and safety across surgeon skill levels. Studies show novices quickly attain high placement accuracy, supporting a shorter learning curve and wider use by less-experienced surgeons.3,22,39 PSI is especially advantageous for anatomically challenging cases—osteoporosis, deformity, or revision—where traditional freehand techniques carry greater risks.31,41 In terms of workflow, PSI-guided approaches have been shown to reduce operative time and fluoroscopy compared with freehand methods, without increasing complications.19,42 Barriers exist: PSI requires preoperative CT imaging, planning, and manufacturing time, and anatomical or logistical issues may be encountered if the intraoperative field differs from the preoperative plan.21,22 Therefore, CBT is not the definitive solution in spine surgery and may not always be beneficial. As with any surgical technique, judicious patient selection is essential for optimal outcomes. Ultimately, PSI democratizes advanced spine instrumentation, supporting improved outcomes in tertiary and community settings, especially as costs decline and workflows integrate more effectively.3,43
Limitations
This review has limitations. Most studies were small, single-center, or case reports with heterogeneous patient populations and limited samples, reducing generalizability and increasing bias. Studies were observational or cadaveric, limiting evidence strength. Follow-up was often brief or inconsistent, hindering the assessment of long-term durability and late complications. There was heterogeneity in how accuracy, breach, and outcomes were defined, preventing meta-analysis. Most research involved high-volume centers with expert surgeons, possibly overstating real-world accuracy and safety. Rapid PSI technological advances mean workflows may not reflect current practice. These issues highlight the need for larger, multicenter, prospective studies with standardized measures and longer follow-up.
Conclusion
PSI for CBT screw placement offers high accuracy, reproducibility, and safety across models and patient groups. It is especially helpful in complex cases, standardizing outcomes for less-experienced surgeons and challenging anatomy. However, evidence is limited by small studies, short follow-up, and few randomized trials. Future research should involve large, multicenter, prospective studies with standardized, long-term outcomes and comparisons with navigation, robotics, and traditional methods. As PSI technology becomes more accessible, its role in improving safety and precision will likely grow, but strong evidence is needed for widespread clinical adoption.
Footnotes
Funding The authors received no financial support for the research, authorship, and/or publication of this article.
Declaration of Conflicting Interests Addisu Mesfin reports Grants from Nuvasive, an OREF grant, DePuy speaking fees, and consulting for Globus.
- This manuscript is generously published free of charge by ISASS, the International Society for the Advancement of Spine Surgery. Copyright © 2026 ISASS. To see more or order reprints or permissions, see http://ijssurgery.com.
References
- 1.↵Kim SJ , Mobbs RJ , Natarajan P , Fonseka RD , Walsh WR . Historical note: the evolution of cortical bone trajectory and associated techniques. Spine Surg Relat Res. 2022;6(1):1–9. 10.22603/ssrr.2021-0059
- 2.↵Peng SB , Yuan XC , Lu WZ , Yu KX . Application of the cortical bone trajectory technique in posterior lumbar fixation. World J Clin Cases. 2023;11(2):255–267. 10.12998/wjcc.v11.i2.255
- 3.↵Fujita R , Oda I , Tanaka H , et al . Real-world clinical accuracy of long cortical bone trajectory screw placement using a patient-specific template guide. J Spine Surg. 2024;10(3):468–478. 10.21037/jss-23-122
- 4.↵Wang Y , Kahaer A , Maimaiti A , Guo H , Rexiti P . Complication, fusion, and revision rate in the lumbar cortical bone trajectory and pedicle screw fixation techniques: a systematic review and meta-analysis. J Orthop Surg Res. 2023;18(1):382. 10.1186/s13018-023-03820-7
- 5.↵Kim KT , Song MG , Lee EC , Seo MS , Lee DY , Kim DH . Can the cortical bone trajectory screw technique be an alternative method to the pedicle screw in posterior lumbar fusion? A systematic review and metaanalysis. Acta Orthop Traumatol Turc. 2021;55(6):552–562. 10.5152/j.aott.2021.21169
- 6.↵Ishii K , Funao H , Isogai N , et al . The history and development of the percutaneous pedicle screw (PPS) system. Medicina (Kaunas). 2022;58(8):1064. 10.3390/medicina58081064
- 7.↵Guo S , Zhu K , Yan MJ , Li XH , Tan J . Cortical bone trajectory screws in the treatment of lumbar degenerative disc disease in patients with osteoporosis. World J Clin Cases. 2022;10(36):13179–13188. 10.12998/wjcc.v10.i36.13179
- 8.↵Okuyama K , Sato K , Abe E , Inaba H , Shimada Y , Murai H . Stability of transpedicle screwing for the osteoporotic spine. An in vitro study of the mechanical stability. Spine (Phila Pa 1986). 1976;18:2240–2245. 10.1097/00007632-199311000-00016
- 9.↵Wittenberg RH , Shea M , Swartz DE , Lee KS , White AA , Hayes WC . Importance of bone mineral density in instrumented spine fusions. Spine (Phila Pa 1986). 1991;16(6):647–652. 10.1097/00007632-199106000-00009
- 10.↵Cook SD , Salkeld SL , Stanley T , Faciane A , Miller SD . Biomechanical study of pedicle screw fixation in severely osteoporotic bone. Spine J. 2004;4(4):402–408. 10.1016/j.spinee.2003.11.010
- 11.↵Halvorson TL , Kelley LA , Thomas KA , Whitecloud TS , Cook SD . Effects of bone mineral density on pedicle screw fixation. Spine (Phila Pa 1986). 1994;19(21):2415–2420. 10.1097/00007632-199411000-00008
- 12.↵Snyder LA , Martinez-Del-Campo E , Neal MT , et al . Lumbar spinal fixation with cortical bone trajectory pedicle screws in 79 patients with degenerative disease: perioperative outcomes and complications. World Neurosurg. 2016;88:205–213. 10.1016/j.wneu.2015.12.065
- 13.↵Phan K , Ramachandran V , Tran TM , et al . Systematic review of cortical bone trajectory versus pedicle screw techniques for lumbosacral spine fusion. J Spine Surg. 2017;3(4):679–688. 10.21037/jss.2017.11.03
- 14.↵Jones-Quaidoo SM , Djurasovic M , Owens RK , Carreon LY . Superior articulating facet violation: percutaneous versus open techniques. SPI. 2013;18(6):593–597. 10.3171/2013.3.SPINE12829
- 15.↵Santoni BG , Hynes RA , McGilvray KC , et al . Cortical bone trajectory for lumbar pedicle screws. Spine J. 2009;9(5):366–373. 10.1016/j.spinee.2008.07.008
- 16.↵Matsukawa K , Yato Y , Imabayashi H , Hosogane N , Asazuma T , Nemoto K . Biomechanical evaluation of the fixation strength of lumbar pedicle screws using cortical bone trajectory: a finite element study. J Neurosurg Spine. 2015;23(4):471–478. 10.3171/2015.1.SPINE141103
- 17.↵Kaye ID , Prasad SK , Vaccaro AR , Hilibrand AS . The cortical bone trajectory for pedicle screw insertion. JBJS Rev. 2017;5(8):e13–e13. 10.2106/JBJS.RVW.16.00120
- 18.↵Lee GW , Son JH , Ahn MW , Kim HJ , Yeom JS . The comparison of pedicle screw and cortical screw in posterior lumbar interbody fusion: a prospective randomized noninferiority trial. Spine J. 2015;15(7):1519–1526. 10.1016/j.spinee.2015.02.038
- 19.↵Matsukawa K , Kaito T , Abe Y . Comparison of safety and perioperative outcomes between patient-specific template-guided and fluoroscopic-assisted freehand lumbar screw placement using cortical bone trajectory technique. Global Spine J. 2024;14(5):1464–1471. 10.1177/21925682221143333
- 20.↵Khan A , Rho K , Mao JZ , et al . Comparing cortical bone trajectories for pedicle screw insertion using robotic guidance and three-dimensional computed tomography navigation. World Neurosurg. 2020;141:e625–e632. 10.1016/j.wneu.2020.05.257
- 21.↵Kim SB , Rhee JM , Lee GS , Lee HY , Kim T , Won Y . Computer-assisted patient-specific prototype template for thoracolumbar cortical bone trajectory screw placement: a cadaveric study. Tech Orthop. 2018;33(4):246–250. 10.1097/BTO.0000000000000285
- 22.↵Matsukawa K , Kaito T , Abe Y . Accuracy of cortical bone trajectory screw placement using patient-specific template guide system. Neurosurg Rev. 2020;43(4):1135–1142. 10.1007/s10143-019-01140-1
- 23.↵Schönthaler W , Dauwe J , Holzer LA . Patient-specific instrumentation in total knee arthroplasty: a review of the current literature. Acta Orthop Belg. 2023;89(2):299–306. 10.52628/89.2.11543
- 24.↵Chan HHL , Nayak P , Alshaygy I , et al . Does freehand, patient-specific instrumentation or surgical navigation perform better for allograft reconstruction after tumor resection? A preclinical synthetic bone study. Clin Orthop Relat Res. 2024;482(10):1896–1908. 10.1097/CORR.0000000000003116
- 25.↵Daigre J , Berlet G , Van Dyke B , Peterson KS , Santrock R . Accuracy and reproducibility using patient-specific instrumentation in total ankle arthroplasty. Foot Ankle Int. 2017;38(4):412–418. 10.1177/1071100716682086
- 26.↵Iannotti JP , Walker K , Rodriguez E , Patterson TE , Jun B-J , Ricchetti ET . Accuracy of 3-dimensional planning, implant templating, and patient-specific instrumentation in anatomic total shoulder arthroplasty. J Bone Joint Surg Am. 2019;101(5):446–457. 10.2106/JBJS.17.01614
- 27.↵Page MJ , McKenzie JE , Bossuyt PM , et al . The PRISMA 2020 statement: an updated guideline for reporting systematic reviews. BMJ. 2021;372:n71. 10.1136/bmj.n71
- 28.↵Munn Z , Barker TH , Moola S , et al . Methodological quality of case series studies. JBI Database System Rev Implement Rep. 2019;Publish Ahead of Print. 10.11124/JBISRIR-D-19-00099
- 29.↵Sterne JAC , Savović J , Page MJ , et al . RoB 2: a revised tool for assessing risk of bias in randomised trials. BMJ. 2019;366:l4898. 10.1136/bmj.l4898
- 30.↵Slim K , Nini E , Forestier D , Kwiatkowski F , Panis Y , Chipponi J . Methodological index for non-randomized studies (minors): development and validation of a new instrument. ANZ J Surg. 2003;73(9):712–716. 10.1046/j.1445-2197.2003.02748.x
- 31.↵Jarvers J-S , Schleifenbaum S , Pfeifle C , et al . Comparison of three different screw trajectories in osteoporotic vertebrae: a biomechanical investigation. BMC Musculoskelet Disord. 2021;22(1):418. 10.1186/s12891-021-04254-0
- 32.↵Peng P , Xu Y , Zhang X , et al . Is a patient-specific drill template via a cortical bone trajectory safe in cervical anterior transpedicular insertion? J Orthop Surg Res. 2018;13(1):91. 10.1186/s13018-018-0810-5
- 33.↵Shi W , Aierken G , Wang S , et al . Application study of three-dimensional printed navigation template between traditional and novel cortical bone trajectory on osteoporosis lumbar spine. J Clin Neurosci. 2021;85:41–48. 10.1016/j.jocn.2020.11.038
- 34.↵Shi W , Aini M , Dang L , et al . Feasibility and improvement of a three-dimensional printed navigation template for modified cortical bone trajectory screw placement in the lumbar spine. Front Surg. 2022;9:1028276. 10.3389/fsurg.2022.1028276
- 35.↵Wang K , Zhang ZJ , Chen JX , Wu AM , Wang XY , Sheng SR . Design and application of individualized, 3-dimensional-printed navigation template for placing cortical bone trajectory screws in middle-upper thoracic spine: cadaver research study. World Neurosurg. 2019;125:e348–e352. 10.1016/j.wneu.2019.01.076
- 36.↵Zhao Y , Liang J , Luo H , Xu Y , Lu S . Double-trajectory lumbar screw placement guided by a set of 3D-printed surgical guide templates: a cadaver study. BMC Musculoskelet Disord. 2021;22(1):296. 10.1186/s12891-021-04149-0
- 37.↵Kim J , Rajadurai J , Choy WJ , et al . Three-dimensional patient-specific guides for intraoperative navigation for cortical screw trajectory pedicle fixation. World Neurosurg. 2019;122:674–679. 10.1016/j.wneu.2018.11.159
- 38.↵Marengo N , Matsukawa K , Monticelli M , et al . Cortical bone trajectory screw placement accuracy with a patient-matched 3-dimensional printed guide in lumbar spinal surgery: a clinical study. World Neurosurg. 2019;130:e98–e104. 10.1016/j.wneu.2019.05.241
- 39.↵Maruo K , Arizumi F , Kusuyama K , Kishima K , Tachibana T . Accuracy and safety of cortical bone trajectory screw placement by an inexperienced surgeon using 3D patient-specific guides for transforaminal lumbar interbody fusion. J Clin Neurosci. 2020;78:147–152. 10.1016/j.jocn.2020.04.090
- 40.↵He K , Dong C , Wei H , et al . A minimally invasive technique using cortical bone trajectory screws assisted by 3D-printed navigation templates in lumbar adjacent segment degeneration. Clin Interv Aging. 2021;16:1403–1413. 10.2147/CIA.S318525
- 41.↵Maruo K , Arizumi F , Kusuyama K , Yoshie N , Tomoyuki K , Tachibana T . Comparison of clinical outcomes after transforaminal interbody fusion using cortical bone trajectory versus percutaneous pedicle screw fixation. World Neurosurg. 2021;151:e821–e827. 10.1016/j.wneu.2021.04.130
- 42.↵Nagashima Y , Ishikawa T , Katsuragi J , et al . Radiation exposure during lumbar interbody fusion surgery can be reduced by using a three-dimensional patient-specific template guide. Cureus. 2024;16(4):e58787. 10.7759/cureus.58787
- 43.↵Di Perna G , Marengo N , Matsukawa K , et al . Three-dimensional patient-matched template guides are able to increase mean diameter and length and to improve accuracy of cortical bone trajectory screws: a 5-year international experience. World Neurosurg. 2023;170:e542–e549. 10.1016/j.wneu.2022.11.066
- 44.↵Zhao Y-H , Ma Y-L , Wang L , et al . Anatomical study of the ideal cortical bone trajectory in the lumbar spine. Medicine (Baltimore). 2021;100(2):e24099. 10.1097/MD.0000000000024099
- 45.↵Wang X , Li HX , Zhu QS , Zhu YH . Effectiveness and safety of robot-assisted versus fluoroscopy-assisted cortical bone trajectory screw instrumentation in spinal surgery: a systematic review and meta-analysis. J Robot Surg. 2024;18(1):78. 10.1007/s11701-024-01866-1
- 46.↵Delgado-Fernández J , Pulido Rivas P , Gil-Simoes R , de Sola RG . How i do it? lumbar cortical bone trajectory fixation with image-guided neuronavigation. Acta Neurochir (Wien). 2019;161(12):2423–2428. 10.1007/s00701-019-04067-0
- 47.↵Garg B , Gupta M , Singh M , Kalyanasundaram D . Outcome and safety analysis of 3D-printed patient-specific pedicle screw jigs for complex spinal deformities: a comparative study. Spine J. 2019;19(1):56–64. 10.1016/j.spinee.2018.05.001
- 48.↵Wallace N , Butt BB , Aleem I , Patel R . Three-dimensional printed drill guides versus fluoroscopic-guided freehand technique for pedicle screw placement: a systematic review and meta-analysis of radiographic, operative, and clinical outcomes. Clin Spine Surg. 2020;33(8):314–322. 10.1097/BSD.0000000000001023
- 49.↵Zhang M , Li J , Fang T , Yan J , Wu L , Zhou Q . Application of 3-dimensional printing guide template and pointed lotus-style regulator in percutaneous pedicle screw fixation for thoracolumbar fractures. Sci Rep. 2022;12(1):2930. 10.1038/s41598-022-06256-x
- 50.↵Lopez CD , Boddapati V , Lee NJ , et al . Three-dimensional printing for preoperative planning and pedicle screw placement in adult spinal deformity: a systematic review. Global Spine J. 2021;11(6):936–949. 10.1177/2192568220944170
- 51.↵Yang W , Guo W , Wu W-J , et al . Accuracy and cost comparison of 3D-printed guides in complex spinal deformity correction: direct vs indirect design. Front Bioeng Biotechnol. 2025;13(1611998):1611998. 10.3389/fbioe.2025.1611998
