3D-printed Navigation Template Research Articles

3D printing navigation template assisted pedicle screw placement for the treatment of typeⅡold odontoid fractures

To compare the safety and clinical efficacy of freehand and 3D printing navigation template assisted screw placement in patients with old odontoid fractures of typeⅡ. Total of 38 patients with old odontoid fractures of typeⅡwere treated from November 2018 to December 2022, all of which presented as chronic neck pain. According to the different methods of screw insertion into the pedicle, the patients were divided into a navigation template group and a freehand group. In the navigation template group, there were 17 patients including 9 males and 8 females with an average age of (51.30±13.20) years old, disease duration was (22.18±7.59) months. In the freehand group, there 21 patients including 7 males and 14 females with an average age of (49.46±11.92) years old, disease duration was (19.52±9.17) months. The intraoperative blood loss, operation time, and postoperative drainage output were recorded and compared between two groups. The accuracy of screw placement was evaluated by CT scan. Before operation and 1 year after operation, cervical pain was assessed by visual analogue scale(VAS), neurological changes were evaluated by the Japanese Orthopaedic Association (JOA) score, and the degree of spinal cord injury was assessed by the American Spinal Injury Association (ASIA) injury scale. All patients were followed up for (25.31±1.21) months. The operation time of template group (112.00±20.48) min had significantly shorter than that of the freehand group(124.29±15.24) min(P<0.05), while there were no significant differences between two groups in terms of intraoperative blood loss, postoperative drainage, and hospital stay(P>0.05). At 1 year after operation, in template group and freehand group, the VAS [(2.88±0.86), (2.90±0.83)] and JOA [(14.94±1.82), (14.62±2.19)] improved with preoperative [VAS(4.71±0.92), (4.86±0.79) and JOA (12.18±2.30), (11.95±2.31)](P<0.05), with no significant difference between two groups (P>0.05). No significant improvement was observed in ASIA grading in either group at 1 year after operation(P>0.05), and there was no significant difference between two groups(P>0.05). The template group had significantly better accuracy of screw placement in the pedicle of the axis than the freehand group (P<0.05), while no significant difference was observed between two groups in the accuracy of screw placement in the pedicle of the atlas (P>0.05). In the treatment of typeⅡold odontoid fractures with posterior pedicle screw fixation, 3D printing navigation template screw placement can significantly shorten the operation time, achieve similar clinical efficacy as free-hand screw placement, and significantly improve the accuracy of screw placement in the pedicle of the axis.

Effectiveness of cannulated screw fixation for femoral neck fracture assisted by three-dimensional printing navigation template in middle-aged and elderly patients.

We sought to explore the effectiveness of cannulated screw fixation for femoral neck fractures in middle-aged and elderly patients assisted by a three-dimensional printing navigation template. A total of 98 middle-aged and elderly patients who underwent cannulated screw fixation for femoral neck fractures were retrospectively analyzed. They were allocated into two groups, each comprising 49 patients. Surgical indexes, hip function, and pain levels were compared between the two groups. The study group, assisted by the three-dimensional printing navigation template, exhibited significantly reduced nail insertion, fewer instances of C-arm fluoroscopy, shorter operation time, quicker time to bone union, earlier initiation of walking exercise, shorter time to weight-bearing walking, and reduced hospital stay than those in the control group (all p<0.001). However, the study group also experienced higher blood loss compared to the control group (p<0.001). Postoperatively, at 3 months and 12 months, the study group demonstrated significantly higher scores compared to the control group (both p<0.001) and reported significantly lower pain scores than that in the other group at 1 week and 12 months post-surgery (both p<0.001). Furthermore, the study group experienced significantly fewer postoperative complications than the control group (p=0.029). Cannulated screw fixation for femoral neck fractures assisted by a 3D printing navigation template is more effective and safer than traditional fixation methods. This approach represents a promising alternative for surgical management.

Experimental study of a 3D-printing technique combined with biphasic calcium phosphates to treat osteonecrosis of the femoral head in a canine model

ObjectiveThis study was aimed to use a digital design of 3D-printing technology to create a surgical navigation template. At the same time, biphasic calcium phosphate (BCP) was applied to treat osteonecrosis of the femoral head (ONFH) in animal models, based on accurate positioning of necrotic lesions in the navigation templates and observation of its therapeutic effect.MethodsFifteen healthy adult male and female beagle dogs weighing 20 + 2 kg were randomly divided into three groups (n = 5) after establishing a model of ONFH using the liquid nitrogen freezing method. Each model underwent necrotic lesion creation and BPC implantations on one side of the femoral head and only necrotic lesion creation on the other side of the femoral head. Each group underwent CT examination, gross observation, histological examination and immunohistochemical staining at 6 weeks, 12 weeks and 18 weeks postoperatively.ResultsAt weeks 6, 12, and 18, CT and gross examination showed that the necrotic area in the experimental group was basically intact and had been completely raised by BCP material. In the control group, there were signs of bone repair in the femoral head, but there were still large bone defects and cavities. At week 18, extensive collapse of the cartilage surface was observed. Through histological examination, in the experimental group at 12 and 18 weeks, a large number of new and reconstructed bone trabeculae containing a large amount of collagen fibres were observed (P < 0.05), while in the control group, there was extensive necrosis of the bone trabeculae without cellular structural areas. Immunohistochemical examination observation: A large number of CD31-positive cells were observed in the experimental group at 6 weeks, gradually decreasing at 12 and 18 weeks (P < 0.05), while a small number of CD31-positive cells were observed in the control group at 18 weeks.ConclusionThe 3D-printed navigation template can accurately locate ONFH lesions. Implantation of BCP material can effectively play a supporting role, prevent the collapse of the loading surface, and induce bone formation and angiogenesis to some extent.

Individualized 3D-printed navigation template-assisted tension band wiring for olecranon fractures

Purpose3D printing techniques guide precision medicine and show great development potential in clinical applications. The purpose of this study was to compare the clinical outcomes of 3D-printed navigation templates versus free-hand in tension band wiring (TBW) procedures for olecranon fractures.MethodsPatients who underwent TBW due to Mayo type II olecranon fractures between January 2019 and December 2021 in our hospital were prospectively enrolled in the study. The patients were divided into the 3D printed navigation template guiding TBW group (3D printed group) and the free-hand TBW group (free-hand group). The primary endpoint of this study was the success rate of the bicortical placement of Kirschner wires (K-wires). Times of intraoperative fluoroscopy, operation times, complications, VAS scores, and Mayo Elbow Performance Scores (MEPS) were analyzed as the secondary outcomes measure.ResultsThe success rate of the bicortical placement of K-wires was 85.7% in the 3D Printed group was significantly higher than the free-hand group (60%). There were fewer times of intraoperative fluoroscopy in the 3D Printed group (1.43 ± 0.51) than that in the free-hand group (2.60 ± 1.00) with statistical significance (P < 0.05). At the date of the last follow-up, four patients suffer from pain and skin injury at the K-wires insertion site in the 3D Printed group and 14 patients in the free-hand group, a significant difference between the two groups (P < 0.05). No statistically significant differences were found in operation time, VAS scores, and MEPS between the two groups.ConclusionsThe individualized 3D-printed navigation template-assisted TBW demonstrated good accuracy and resulted in reduced times of intraoperative fluoroscopy and complication compared to the free-hand TBW for olecranon fractures.

Application of 3D printing navigation system in pediatric epiphyseal complex lesion surgery

To investigate 3D printing navigation system in pediatric epiphyseal complex lesion surgery. 10 children with epiphyseal complex lesions of the lower limb were recruited. After collecting imaging data such as CT and MRI in children with epiphyseal complex lesions of the lower limb, a three-dimensional model of bone was constructed using 3D printed computer modeling technologies for the localization of the lesion area. The extent of bone bridges was less than 30%, and all of them met the indications for bone bridge resection surgery. 3D printed navigation templates guided lesion resection. Epiphyseal block growth regulation with a figure-of-eight plate was also used in cases with preexisting abnormal alignment. During the operation, the average surgical incision was 4.0 cm, the bone bridge positioning was accurate, and the bone bridge tissue could be successfully and completely removed. As a result of follow-up, no cases had residual bone bridge tissue, no iatrogenic epiphyseal injury was found, and the epiphyseal plate was open in all children. 3D printing navigation system improved the accuracy of resection of lower limb epiphyseal complex lesions, significantly reduced the need for intraoperative fluoroscopy, avoided iatrogenic injury to the epiphyseal complex due to positioning errors, thereby reducing postoperative complications and considerably improving the prognosis of a series of lower limb epiphyseal complex lesion diseases in children.

Comparison of 3D-printed Navigation Template-assisted Pedicle Screws versus Freehand Screws for Scoliosis in Children and Adolescents: A Systematic Review and Meta-analysis.

There is a lack of attention to screw placement techniques for surgical treatment of scoliosis in children and adolescents. This meta-analysis aims to compare the accuracy and safety of pedicle screw placement between the 3D-printed navigation template technique and the freehand technique during corrective surgery for scoliosis in children and adolescents. A comprehensive search was conducted for relevant articles up to December 2021 in databases including PubMed, Embase, MEDLINE, Cochrane, and Web of Science. The systematic meta-analysis compared the efficacy of pedicle screw placement between the two techniques, including accuracy of pedicle screw placement, complication rate, operation time, blood loss, mean placement time per screw, and mean times for fluoroscopy. The seven articles analyzed in this study involved 229 patients altogether. A total of 2,805 pedicle screws were placed by the two methods. Our results revealed that the 3D-printed guide template technique was more accurate than the freehand technique in pedicle screw placement (odds ratio [OR] =2.96; 95% confidence interval [CI]: 2.24-3.91; p < 0.000) with a lower complication rate (OR = 0.21; 95% CI: 0.06-0.78; p = 0.02). The operation time (mean difference [MD] = -34.37; 95% CI: -67.47 to -1.28; p = 0.04) and mean placement time per screw (MD = -3.11; 95% CI: -6.13 to -0.09; p = 0.04) and mean times for fluoroscopy (MD = -6.60; 95% CI: -8.66 to -4.55; p < 0.000) significantly decreased among patients in the 3D-printed navigation template group compared with those in the freehand technique group. In addition, the two techniques had no significant statistical difference in blood loss. Compared with the traditional freehand technique, the 3D-printed guide template is a promising technique with higher accuracy and safety in screw placement for surgical treatment of scoliosis in children and adolescents, and is worth popularizing and validating through more prospective clinical studies.

Feasibility and improvement of a three-dimensional printed navigation template for modified cortical bone trajectory screw placement in the lumbar spine.

Compared with traditional pedicle screw trajectory, cortical bone trajectory (CBT) increases the contact surface between the screw and cortical bone where the screw is surrounded by dense cortical bone, which does not deform remarkably due to degeneration. We aimed to provide detailed information about the improvement of three-dimensional (3D)-printed navigation templates for modified CBT screw placement in the lumbar spine and evaluate the safety and accuracy thereof. Four human cadaveric lumbar spine specimens were selected. After CT scanning data were reconstructed to 3D models, either the left or right side of each specimen was randomly selected to establish a 3D-navigation template, mutually complemented with the surface anatomical structure of the lateral margin of the lumbar isthmus, vertebral plate, and spinous process. The corresponding 3D centrum was printed according to the CT scanning data, and a navigation template of supporting design was made according to modified cortical bone technique. The same template was used to insert CBT screws into 3D printed and cadaveric specimens. After the screws were inserted, the screw path of the 3D printed specimens was directly observed, and that of the anatomical specimens was scanned by CT, to determine the position and direction of the screws to analyze the success rate of screw placement. Twenty cortical bone screws were placed in each of the 3D printed and anatomical specimens, with excellent rates of screw placement of 100% and 95%, respectively. We report the easy, safe, accurate, and reliable use of a 3D-printed navigation template to carry out screw placement by modified cortical bone technique in the lumbar spine.

Comparison of Perpendicular to the Coronal Plane versus Medial Inclination for C2 Pedicle Screw Insertion Assisted by 3D Printed Navigation Template.

C2 pedicle screw insertion is very important in posterior upper cervical surgery. The traditional screw placement technique requires us to consider both medial inclination and cephalad angle, it is difficult to operate intraoperatively. This paper is to explore a novel method of C2 pedicle screw placement compared with traditional C2 pedicle screw. A total of 44 patients diagnosed with atlantoaxial fracture or instability from May 2018 to November 2020 were involved in this retrospective study, and they were divided into C2-PPS group (perpendicular to the coronal plane C2 screw, 24 patients) and C2-TPS group (traditional C2 pedicle screw, 20 patients). The diameter of the maximum tangential circle, distance between geometric center and median sagittal plane and screw length of PPS and TPS were measured based on the 3D model of C2, respectively. Then the 3D printed navigation templated were designed and manufactured by 3D printing to assisted the PPS and TPS placement, respectively. The surgical time and radiation exposure times during operation were recorded; the post-operative grading criteria, deviation of screw entry point and deviation of screw angle of two groups were evaluated, respectively. A total of 48 screws were inserted in the C2-PPS group, and 40 screws were inserted in the C2-TPS group. There were 46 screws with grade 0 (95.8%) in the PPS group and 31 screws with grade 0 (77.5%) in the TPS group, (P=0.03). The radiation exposure times in the C2-PPS group and C2-TPS group were 4.7 ± 1.5 and 7.8 ± 3.8, respectively, (P=0.045). The deviations of screw entry point in the C2-PPS group and C2-TPS group were 1.2 ± 0.8 mm and 3.2 ± 1.3 mm, respectively; the deviations of screw angle in the C2-PPS group and C2-TPS group were 2.1 ± 1.6° and 4.8 ± 2.0°, respectively, (P=0.000). The diameters of the maximum tangential circle in the C2-PPS group and C2-TPS group were 5.5 ± 1.0 mm and 5.3 ± 0.9 mm, respectively. The distances between the geometric center and median sagittal plane in the C2-PPS group and C2-TPS group were 15.4 ± 2.3 mm and 18.0 ± 3.3 mm, respectively; The screw lengths in the C2-PPS group and C2-TPS group were 25.9 ± 3.2 mm and 27.6 ± 3.7 mm, respectively, (P=0.000). Eighty percent of C2-PPS corridor can accommodate a 3.5 mm diameter screw, and with an average screw length of 26 mm. Navigation templates assisted the C2-PPS placement is less surgical time, less radiation exposure times, more safe and more accurate than C2-TPS.

Individualized 3D printed navigation template-assisted atlantoaxial pedicle screws vs. free-hand screws for the treatment of upper cervical fractures.

ObjectiveThis study aims to compare the efficacy and safety of freehand atlantoaxial pedicle screws against custom 3D printed navigation template screws in the treatment of upper cervical fractures.MethodsIn our institution from 2010 to 2020, a retrospective cohort analysis of 23 patients with upper cervical fractures was done. These patients were separated into two groups: group A (N = 12), which received customized 3D printed navigation template-assisted screws with virtual reality techniques, and group B (N = 11), which received freehand screws assisted by intraoperative fluoroscopy. Every patient was monitored for more than 1 year. The two groups were contrasted in terms of screw implant accuracy, cervical spine Japanese Orthopaedic Association (JOA) score, American Spinal Injury Association (ASIA) score, visual analogue scale (VAS) score, surgical time, fluoroscopy times, and intraoperative blood loss.ResultsA total of 88 atlantoaxial pedicle screws in all, 46 in group A and 42 in group B, were implanted. In group A, the screw insertion accuracy rate was 95.7%, compared to 80.0% in group B (P < 0.05). When compared to group B, group A had shorter surgery times, less blood loss, fewer fluoroscopies, a higher short-term JOA score, and overt pain reduction (P < 0.05). However, there was no discernible difference between the two groups' VAS scores, long-term JOA scores, or ASIA scores (sensory and motor), at the most recent follow-up.ConclusionIndividualized 3D printed guide leads to significant improvement in the screw safety, efficacy, and accuracy, which may be a promising strategy for the treatment of upper cervical fractures.

Performance of Tönnis triple osteotomy in older children with developmental dysplasia of the hip (DDH) assisted by a 3D printing navigation template

BackgroundThe objective of this study is to investigate the preparation of a navigation template via a computer-aided design (CAD) and 3D printing (3DP) in order to improve the effectiveness of Tönnis triple osteotomy in older children with developmental dysplasia of the hip (DDH).MethodThirty-eight older children who received Tönnis triple osteotomy were included in this study. Among them, 20 were categorized as the 3DP navigation template group (3DP group), and the remaining 18 were categorized as the conventional surgery group (CS group). Data, including preoperative and postoperative pelvic sharp angle (SA), lateral center-edge angle (LCEA), acetabular roof angle (ARA), acetabular head index (AHI), crossover sign (COS), ischial spine sign (ISS), operation time (OT), intraoperative blood loss (IBL), and number of radiation exposures (NORE) were recorded for both groups. In addition, the therapeutic effect was evaluated at the last follow-up, according to the McKay criteria and Severin’s criteria.ResultsIn the 3DP and CS groups, the mean OT was 126.6 ± 17.6 min and 156.0 ± 18.6 min, respectively; the mean IBL was 115.0 ± 16.9 ml and 135.7 ± 26.5 ml, respectively; the NORE were 3.3 ± 0.8 times and 8.6 ± 1.3 times, respectively. There were significant differences in the OT, IBL, and NORE between the two groups (P = 0.03, 0.05, < 0.001, respectively). At the last follow-up, the 3DP and CS groups displayed SA of 41.8 ± 2.3° and 42.6 ± 3.1°, respectively; LCEA of 35.6 ± 4.2° and 37.1 ± 2.8°, respectively; ARA of 6.9 ± 1.8° and 9.8 ± 2.6°, respectively; and AHI of 86.6 ± 4.1% and 84.3 ± 2.8%, respectively; COS(+) of 5 hips and 4 hips, respectively; ISS(+) of 6 hips and 7 hips. We observed no statistical differences in the SA, LCEA, ARA, AHI, COS and ISS between the two groups (P = 0.918, 0.846, 0.643, 0.891, 0.841, 0.564, respectively). According to the McKay criteria, the 3DP group had 10 excellent, 6 good, and 4 general hips, whereas, the CS group had 12 excellent, 4 good, and 2 general hip. There was no statistical difference between the two groups (P = 0.698). In 3DP group the postoperative Severin’s grading included 13 hips in grade I, 4 in grade II, 3 in grade III. Alternately, in the CS group, the postoperative Severin’s grading included 11 hips in grade I, 5 in grade II, 2 in grade III. The Severin ‘s criteria also showed no statistical difference between the two groups (P = 0.945).ConclusionsBase on our analysis, our CAD-3DP-fabricated navigation template assisted Tönnis triple osteotomy in older DDH children, it reduced operation time and number of radiation exposures. However, no significant differences in radiological assessment and functional outcomes were observed when an experienced surgeon performs the surgery. Therefore, Surgeons who have less experience in triple osteotomy profit more from the application of this technology.

Application of three-dimensional printed navigation templates to correct lower limb deformities in children by the guided growth technique.

Currently, individualized navigation templates are rarely applied in pediatric orthopedic surgery. This study aimed to explore the potential of navigation templates obtained using computer-aided design and three-dimensional (3D) printing to correct lower limb deformities in children by the guided growth technique. We prospectively studied 45 children with leg length discrepancy (LLD) or lower limb angular deformities, who underwent guided growth surgery involving 8-plate. In total, 21 and 24 children were included in the navigation template (group A) group and in the traditional surgery (group B) group, respectively. Mimics software was used for designing and printing navigation templates. The operation time, X-ray radiation exposure, damage to cartilage, and postoperative complications were recorded. The mean operation time in groups A and B were 20.78 and 28.39 min, respectively, and the difference was statistically significant. Compared with group B, the intraoperative exposure of X-rays in group A was reduced by 25% on average. After 9-24 months of follow-up, the deformities were corrected in both groups. No significant differences in the treatment effect were noted between the groups, and no complications occurred. Using the individualized navigation template in the guided growth technique made the surgical procedure convenient and simple to perform. In addition, the operation time and intraoperative exposure to X-rays were reduced. We consider that 3D printed navigation templates can facilitate the accurate completion of corrective surgeries for lower limb deformities in children, which is worthy of promotion and application.

A Novel Adjustable EndoButton Fixation Assisted by 3D Printing Technology for Tibiofibular Syndesmosis Injury: A Biomechanical Study.

Purpose: The recommendations for surgical fixation of tibiofibular syndesmosis injuries are increasingly challenging for many clinical orthopedists, as international consensus has not been published for the optimal treatment of the injury. Thus, we have created a 3D-printed navigation template for a precise bone tunnel and a novel adjustable EndoButton fixation (NAE) for the ideal treatment. The purpose of this research was to evaluate the accuracy of the 3D-printed navigation template and explore the biomechanical performance of the NAE technique by comparing it with the intact syndesmosis, screw technique, and TightRope (TR) technique. Methods: Twenty-four human cadaveric legs were randomly allocated to four groups: the NAE group (n = 6), TR group (n = 6), screw group (n = 6), and intact group (n = 6). A personalized navigation template based on computed tomography scans was designed, and 3D printing models were generated for the distal tibiofibular syndesmosis. The NAE, TR, and screw group were performed via 3D-printed navigation template, respectively. All groups were tested under increasing loading forces including axial loading (from 100 N to 700 N) and torsional loading (from 1 N to 5 N), which were performed in different ankle positions. The displacements of the tibiofibular syndesmosis were analyzed using the Bose Electroforce 3510-AT biomechanical testing equipment. Results: Surgical fixations were conducted successfully through a 3D-printed navigation template. Both in axial or torsional loading experiments, no statistically significant difference was observed in the displacements among the NAE, TR, and intact groups in most situations (p > 0.05), whereas the screw group demonstrated obviously smaller displacements than the abovementioned three groups (p < 0.05). Conclusion: The 3D printing technology application may become beneficial and favorable for locating and making the bone tunnel. Also, the NAE fixation provides the performance of complete ligaments; it also restores physiologic micromotion and avoids insufficient or excessive reduction when compared to the TR and screw technique. This may offer a new fixation for the treatment of tibiofibular syndesmosis injuries that is desirable for clinical promotion.

Clinical Application of a 3D-Printed Positioning Module and Navigation Template for Percutaneous Vertebroplasty.

This study aimed to evaluate a personalized 3D-printed percutaneous vertebroplasty positioning module and navigation template based on preoperative CT scan data that was designed to treat patients with vertebral compression fractures caused by osteoporosis. A total of 22 patients with vertebral compression fractures admitted to our hospital were included in the study. Positioning was performed with the new 3D-printed positioning module, and the navigation template was used for patients in the experimental group, and the traditional perspective method was used for patients in the control group. The experimental group consisted of 11 patients, 2 males and 9 females, with a mean age of 67.27 ± 11.86 years (range: 48 to 80 years), and the control group consisted of 11 patients, 3 males and 8 females, with a mean age of 74.27 ± 7.24 years (range: 63 to 89 years). The puncture positioning duration, number of intraoperative fluoroscopy sessions, and preoperative and postoperative visual analog scale (VAS) scores were statistically analyzed in both groups. The experimental group had shorter puncture positioning durations and fewer intraoperative fluoroscopy sessions than the control group, and the differences were statistically significant (P < .05). There were no significant differences in age or preoperative or postoperative VAS scores between the two groups (P > .05). The new 3D-printed vertebroplasty positioning module and navigation template shortened the operation time and reduced the number of intraoperative fluoroscopy sessions. It also reduced the difficulty in performing percutaneous vertebroplasty and influenced the learning curve of senior doctors learning this operation to a certain degree.

3D printed templates improve the accuracy and safety of pedicle screw placement in the treatment of pediatric congenital scoliosis

BackgroundThree-dimensional (3-D) printed guidance templates are being increasingly used in spine surgery. The purpose of this study was to determine if 3D printed navigation templates can improve the accuracy of pedicle screw placement and decrease the complication rate compared to freehand screw placement in the treatment of children with congenital scoliosis.MethodsThe records of pediatric patients with congenital scoliosis treated at our hospital from January 2017 to January 2019 were retrospectively reviewed. Patients were divided into those where a 3D printed guidance templated was used and those in which the freehand method was used for pedicle screw placement. The accuracy rate of pedicle screw placement, surgical outcomes, and complications were compared between groups.ResultsA total of 67 children with congenital scoliosis were included (43 males and 24 females; mean age of 4.13 ± 2.66 years; range, 2–15 years). There were 34 children in the template-assisted group and 33 in the freehand group. The excellent accuracy rate of pedicle screw placement was significantly higher in the template-assisted group (96.10% vs. 88.64%, P = 0.007). The main Cobb angle and kyphosis angle were similar between the 2 groups preoperatively and postoperatively (all, P > 0.05), and in both groups both angles were significantly decreased after surgery as compared to the preoperative values (all, P < 0.001). The degree of change of the Cobb angle of the main curve and kyphosis angle were not significantly different between the 2 groups. There were no postoperative complications in the template group and 4 in the freehand group (0% vs. 12.12%; P = 0.009). All 4 patients with complications required revision surgery.

Application of a Personalized Finite Element Analysis and 3D-Printed Navigation Template in the Treatment of Femoral Neck Fracture with Cannulated Screw

PurposeTo investigate the feasibility and accuracy of combining a personalized finite element analysis with 3D-printed navigation template on the treatment of femoral neck fracture (FNF) with cannulated screw.MethodsA total of 60 patients as unstable FNT were evolved and randomly divided into two groups. The subjects in the study group were examined using a finite element analysis according to the three-dimensional CT of hip joint before operation and then underwent 3D-printed navigation template of the femur to complete the implantation of cannulated screw, whereas the other 30 patients in the control group were underwent the implantation of cannulated screw using the conventional FNF treatment.ResultsThe biomechanics of three screws were more stable when they were close to the bone cortex (< 3 mm). Furthermore, it was demonstrated that the patients in the study group had more effectively success rate of one-time nail placement and significant reduction in the distance of talus cortex than those in the control group. At 12 months post-surgery, higher healing rate of fracture and Harris functional score of hip, as well as lower necrosis rate of femoral head were underwent in the study group when compared to the control group.ConclusionTotally, the combined application of a personalized finite element analysis and 3D-printed navigation template in the treatment of FNF can not only improve the effective nail placement, but also make the screw more in line with the requirements of biomechanical stability to promote the fracture healing and reduce the risk of femoral head necrosis.

Application of 3D-printed navigation plate in pulsed radiofrequency therapy of dorsal root ganglion in thoracic postherpetic neuralgia

Objective: To evaluate the accuracy, efficacy and safety of 3D-printed personalized navigation template in the treatment of thoracic postherpetic neuralgia (PHN) with dorsal root ganglion pulsed radiofrequency (DRG-PRF). Methods: A total of 63 patients with thoracic PHN from March 2019 to December 2020 in Nanjing Drum Tower Hospital, the Affiliated Hospital of Nanjing University Medical School were enrolled and randomly divided into study group (n=31) and control group (n=32) by random number table method. The study group received DRG-PRF treatment assisted by 3D-printed navigation template, while the control group received DRG-PRF treatment guided by conventional CT. The one-time success rate of puncture, the incidence of puncture times ≥3, the number of punctures, puncture time, visual analogue scale (VAS) score and surgical complications between the two groups were compared. Results: The one-time success rate of puncture in study group was 84.9% (79/93), which was higher than that of control group [30.2% (29/96)] (P<0.001). The incidence of puncture times ≥3, the number of punctures, puncture time in study group were 4.3% (4/93), 1 (1, 1) and 2.9 (2.8, 3.0) min, respectively, which were lower than that of the control group [21.9% (21/96), 2(1, 3), 9.0 (4.5, 12.9) min, respectively] (all P<0.01). No difference was found in VAS score at each time point before and after surgery between the two groups (all P>0.05). There was one case of pleura puncture in the control group, but no other complications such as straying into vertebral canal, hematoma, spinal cord injury, limb movement disorder, infection were found in the two groups. Conclusions: 3D-printed personalized navigation template is an effective method to guide DRG-PRF for the treatment of thoracic postherpetic neuralgia. It can significantly improve the surgical efficiency of DRG-PRF, but has no significant effect on the surgical efficacy.

Biomechanical testing of three coracoclavicular ligament reconstruction techniques with a 3D printing navigation template for clavicle-coracoid drilling.

BackgroundThe identification and precise clavicle-coracoid drilling during coracoclavicular (CC) ligament reconstruction for acromioclavicular (AC) joint dislocation require a high level of experience and surgical skills. Furthermore, the improvement of flexible fixation, such as Endobutton techniques for CC ligament reconstructions is ongoing. We have developed a 3D printing technique navigation template for clavicle-coracoid drilling and a novel implant for the reconstruction. This study aimed to determine the efficiency of the navigation template for clavicle-coracoid drilling and to evaluate the biomechanical performance of the novel CC ligament reconstruction technique.MethodsA total of 24 fresh-frozen human cadaveric shoulders were randomly assigned to 1 of 3 reconstruction groups or a control group: TightRope, Triple Endobutton, and the Adjustable Closed-Loop Double Endobutton technique. Computed tomography scans, navigation template designs, and 3D printing were performed for the shoulders. Then, AC joint dislocation was simulated in the reconstruction groups, and 3 CC ligament reconstruction techniques were operated via the 3D printing template separately. Furthermore, biomechanical protocols including the translation test (load from 5 to 70 N) and the load-to-failure test were performed to characterize the behaviors and strengths. One-way ANOVA test analyzed differences in displacement under the translation load and the load at failure.ResultsCC ligament reconstructions were performed successfully along with the 3D printing navigation template in the 3 reconstruction groups. During the translation test, no significant difference was found in displacements among the 4 groups. Meanwhile, the mean load of all reconstruction groups at failure (Adjustable Closed-Loop Double Endobutton, 722.1620 N; TightRope, 680.4020 N; Triple Endobutton, 868.5762 N) was significantly larger than the control group (564.6264 N, P<0.05). The Triple Endobutton group had the maximum load at failure (P<0.05), however, no significant difference was noticed between the other 2 reconstruction groups (P>0.05).ConclusionsThe 3D printing navigation template may become helpful and reliable for AC joint dislocation surgery. Among the 3 CC ligament reconstruction techniques, the Triple Endobutton technique has the best strength in terms of biomechanics, while the biomechanical strength of the Adjustable Closed-Loop Double Endobutton technique is reliable in comparison with the TightRope technique.

A Minimally Invasive Technique Using Cortical Bone Trajectory Screws Assisted by 3D-Printed Navigation Templates in Lumbar Adjacent Segment Degeneration.

PurposeRevision surgery for adjacent segment degeneration (ASD) commonly requires exposing and removing the original fixation. To minimize trauma and to reduce the operation time and blood loss, we introduced a minimally invasive lumbar revision technique using cortical bone trajectory (CBT) screws assisted by three-dimensional (3D)-printed navigation templates.MethodsFrom April 2017 to October 2019, 18 patients with ASD underwent revision surgery with CBT screws assisted by 3D-printed templates in our hospital. All surgical data, including the operation time, blood loss, and incision length, were recorded. We evaluated the clinical efficacy using the visual analog scale (VAS), the Oswestry Disability Index (ODI), and the Japanese Orthopedic Association (JOA) score. X-ray and computed tomography (CT) scans were used to evaluate the stability of CBT screw fixation, the accuracy of screws, and the fusion rate.ResultsThe mean follow-up was 22.4±4.7 months (12–31 months). The VAS, ODI, and JOA scores were analyzed by SPSS 21.0 and showed significant improvement at 2 weeks and the last follow-up compared with preoperative data (P<0.05). Seventy-six CBT screws were inserted with navigation templates; 2 screws were Grade B, and the other screws were Grade 0 or A. Changes in intervertebral height showed good stability of CBT screw fixation (P>0.05). All the patients exhibited satisfactory fusion results.ConclusionRevision surgery for ASD with CBT screws assisted by 3D-printed navigation templates has satisfactory clinical efficacy with the advantages of a short operation time, a small incision, and less blood loss.

Application study of three-dimensional printed navigation template between traditional and novel cortical bone trajectory on osteoporosis lumbar spine

To investigate the safety, accuracy and indications of traditional and novel cortical bone screws placement for osteoporosis lumbar spine, 4 lumbar vertebra specimens (2 males and 2 females) were used for this study. After the computed tomography scanning data of the above anatomical specimens were three-dimensional (3D) reconstructed, one side of each anatomical specimen was randomly chosen to place traditional cortical bone screws, and the other side received novel technical placement. The safety screw trajectory was designed, and a 3D navigation template complementary to the surface anatomical structure of lumbar isthmus lateral margin-vertebral plate-spinous process part was established. The designed supporting navigation template was substantialized, and the navigation template replicated different cortical bone screw trajectory at different sides of the same one lumbar vertebra. Forty cortical bone screws were firstly placed in 3D printed vertebra and then 40 were placed in real anatomical specimens. In 3D printed specimens, the success rates of screw placement with navigation template using traditional and novel techniques were both 100%. While in anatomical specimens, the success rate of screw placement using traditional and novel navigation template was 97.5% (one out of 40 went wrong). Therefore, it is safe, accurate and reliable to place traditional and novel cortical bone screws on osteoporosis lumbar spine using 3D printed navigation template. Traditional and novel screw placement methods should be flexibly applied or combined according to specific sequence and form of vertebra.

Application of 3D printing guide plate in total hip arthroplasty for developmental dysplasia of the hip

To explore the value of 3D-printed navigation template using in total hip arthroplasty(THA)for developmental dysplasia of the hip (DDH). Twenty five patients with DDH underwent total hip arthroplasty from February 2016 to May 2018 were analyzed retrospectively, including 4 males and 21 females, aged from 40 to 75 years old. Among them, 5 cases were Crowe typeⅡ, 14 cases were Crowe type Ⅲ and 6 cases were Crowe type Ⅳ. Twelve cases of them underwent THA with the 3D printing navigation plate, another 13 cases underwent the same operation but without the aid of navigation templates. All patients were treated by the same operators. The operating time, intra- and post-operative hemorrhage and Harris Hip Score(HHS) at six months postoperativelywere compared, anteversion angle, abduction angle and the distance from rotation center to the ischial tuberosity connection between ipsilateral and contralateral sides were also compared. All of the patients were followed up for 12 to 26 months. The operation time, intra- and post-operative hemorrhage and Harris score in the 3D printing group were better than those in the conventional hip replacement group(P<0.05). There were no significant differences in anteversion angle, abduction angle and the distance from rotation center to the ischial tuberosity connection between ipsilateral and contralateral sides in 3D printing group (P>0.05). The abduction angle and the distance from rotation center to the ischial tuberosity connection were significantly different between the two sides in the traditional group (P< 0.05), the abduction angles had no statistical difference (P=0.487) between two sides. The 3D-printed operation navigation template technique is an individualized, accurate and promisingtechnique for THA with DDH.