3-Dimensional printing guide template assisted percutaneous vertebroplasty: Technical note

Three-dimensional analysis of puncture needle path through safety triangle approach PLD and design of puncture positioning guide plate

OBJECTIVE

In this study, the three-dimensional relationship between the optimal puncture needle path and the lumbar spinous process was discussed using digital technology. Additionally, the positioning guide plate was designed and 3D printed in order to simulate the surgical puncture of specimens. This plate served as an important reference for the preoperative simulation and clinical application of percutaneous laser decompression (PLD).

METHOD

The CT data were imported into the Mimics program, the 3D model was rebuilt, the ideal puncture line N and the associated central axis M were developed, and the required data were measured. All of these steps were completed. A total of five adult specimens were chosen for CT scanning; the data were imported into the Mimics program; positioning guide plates were generated and 3D printed; a simulated surgical puncture of the specimens was carried out; an X-ray inspection was carried out; and an analysis of the puncture accuracy was carried out.

RESULTS

(1) The angle between line N and line M was 42°~55°, and the angles between the line M and 3D plane were 1°~2°, 5°~12°, and 78°~84°, respectively; (2) As the level of the lumbar intervertebral disc decreases, the distance from point to line and point to surface changes regularly; (3) The positioning guide was designed with the end of the lumbar spinous process and the posterior superior iliac spine on both sides as supporting points. (4) Five specimens were punctured 40 times by using the guide to simulate surgical puncture, and the success rate was 97.5%.

CONCLUSION

By analyzing the three-dimensional relationship between the optimal puncture needle path and the lumbar spinous process, the guide plate was designed to simulate surgical puncture, and the individualized safety positioning of percutaneous puncture was obtained.

Thoracolumbar Osteoporotic Vertebral Compression Fracture Treatment by Unilateral Percutaneous Vertebroplasty Using Curved Diffusion Needle

Objective

To investigate the clinical effect of unilateral puncture vertebroplasty with curved diffusion needle (CDN) in the treatment of thoracolumbar osteoporotic vertebral compression fracture (OVCFs).

Methods

We used the method of a retrospective study. The clinical data of 38 patients with OVCFs treated by unilateral puncture vertebroplasty with curved diffusion needle from January 2021 to January 2022 were analyzed. The operation time and the amount of bone cement injected were recorded to observe the leakage and dispersion of bone cement during the operation and the incidence of vertebral re-fracture at the last follow-up. Visual analog scale (VAS) and Oswestry disability index (ODI) were used to evaluate the pain and functional improvement before and after surgery.

Results

All patients successfully completed the operation. The operation time was 31.2 ± 5.1 min, and the bone cement injection volume was 4.8 ± 1.1 ml. During the operation, three patients had bone cement leakage, and the leakage rate was 7.8%. The bone cement dispersion was excellent in 31 cases, among which seven cases were good; the postoperative follow-up time was 3-10 months, with an average of 6.3 months; no vertebral body re-fracture occurred. VAS score and ODI at 1d after the operation and at the last follow-up were significantly improved compared with those before the operation, and the difference was statistically significant (P < 0.05). Also there was a significant difference between the postoperative 1d and the last follow-up (P < 0.05).

Conclusions

Unilateral puncture vertebroplasty for the treatment of thoracolumbar OVCFs can obtain good bone cement distribution, safety and does not increase complications, and the clinical effect is satisfactory.

O-Arm- and Guide-Device-Assisted Personalized Percutaneous Kyphoplasty for Thoracolumbar Osteoporotic Vertebral Compression Fractures

With the ageing of the global population, the incidence of osteoporotic vertebral compression fractures (OVCFs) is increasing. To assess the safety and efficacy of O-arm- and guide-device-assisted personalized percutaneous kyphoplasty (PKP) for treating thoracolumbar OVCFs, a total of 38 consecutive thoracolumbar OVCF patients who underwent bilateral PKP assisted with an O-arm and a guide device (O-GD group, n = 16) or traditional fluoroscopy (TF group, n = 22) from January 2020 to December 2021 were retrospectively reviewed, and their epidemiologic, clinical and radiological outcomes were analysed. The operation time was significantly decreased (p < 0.001) in the O-GD group (38.3 ± 12.2 min) compared with the TF group (57.2 ± 9.7 min). The number of intraoperative fluoroscopy exposures was significantly decreased (p < 0.001) in the O-GD group (31.9 ± 4.5) compared with the TF group (46.7 ± 7.2). Intraoperative blood loss was significantly decreased (p = 0.031) in the O-GD group (6.9 ± 2.5 mL) compared with the TF group (9.1 ± 3.3 mL). No significant difference (p = 0.854) in the volume of injected cement was observed between the O-GD group (6.8 ± 1.3 mL) and the TF group (6.7 ± 1.7 mL). Both the clinical and radiological outcomes, including the visual analogue scale score for pain, Oswestry Disability Index and anterior height and local kyphotic angle of the fractured vertebrae, were significantly improved at the postoperative and final follow-up but did not differ between the two groups. The incidence of cement leakage and refracture of the vertebral body was similar in the two groups (p = 0.272; p = 0.871). Our preliminary study demonstrated that O-GD-assisted PKP is a safe and effective procedure that presents a significantly shorter operation time, fewer intraoperative fluoroscopy exposures and less intraoperative blood loss than the TF technique.

Robot-assisted percutaneous vertebroplasty for osteoporotic vertebral compression fractures: a retrospective matched-cohort study

PURPOSE

This study aims to introduce the principle, clinical efficacy, and learning curve of robot-assisted percutaneous vertebroplasty (PVP).

METHODS

Forty-two patients who underwent robot-assisted single-level PVP were analyzed retrospectively and 42 age-matched patients using freehand technique were selected as the control group. The visual analog scale, operation time, radiation exposure, accuracy, and learning curve were analyzed.

RESULTS

The puncture time and total operation time were significantly shorter, and the puncture and total fluoroscopy number were fewer in the robot group. The deviation between pre-operative planned and actual puncture trajectory well met clinical requirement. The puncture time, total operation time, and puncture fluoroscopy number were significantly more in early cases than in later cases in the robot group.

CONCLUSION

The robot-assisted pedicle puncture technique shortens the operation time and reduces radiation exposure, and the accuracy meets the clinical requirement in PVP. The learning curve is short and not steep.

Robot Versus Fluoroscopy-Assisted Vertebroplasty and Kyphoplasty for Osteoporotic Vertebral Compression Fractures: A Systematic Review and Meta-analysis

OBJECTIVE

This study aimed to conduct a systematic review and meta-analysis to compare the clinical results and complications of robot-assisted (RA) versus fluoroscopy-assisted (FA) percutaneous vertebral augmentation (PVA) in the treatment of osteoporotic vertebral compression fractures (OVCFs).

METHODS

A comprehensive search of online databases including PubMed, Embase, Cochrane Library, web of science, and core journals of China National Knowledge Infrastructure were performed to identify related studies reporting the clinical results and complications of RA versus FA-assisted PVA in the treatment of OVCFs. The rate of bone cement leakage was used to assess the complications. After the surgery, the clinical findings were analyzed using the Visual Analog Scale scores and the Oswestry Disability Index scores. The surgical time, intraoperative fluoroscopy frequency, and x-ray exposure duration were used to evaluate the perioperative results. Forest plots were constructed to investigate the results.

RESULTS

RA-PVA had a significantly lower bone cement leakage rate, shorter fluoroscopy frequency, and shorter radiation exposure time of doctors compared with FA-PVA. However, no significant differences were found between RA-PVA and FA-PVA in operative time and radiation exposure time of patients. Furthermore, no statistically differences were found between the 2 groups in Visual Analog Scale and Oswestry Disability Index scores after surgery.

CONCLUSIONS

This meta-analysis showed that RA-PVA can reduce bone cement leakage rate, fluoroscopy frequency, and doctors' radiation exposure time. With the advancement of RA technology, we anticipate more high-quality randomized controlled trials of RA versus FA-PVA in the future to validate and update the results of this analysis.

Robot-Assisted Versus Fluoroscopy-Assisted Kyphoplasty in the Treatment of Osteoporotic Vertebral Compression Fracture: A Retrospective Study

STUDY DESIGN

A retrospective study.

OBJECTIVES

To compare the clinical and radiological outcomes of robot assisted (RA) and fluoroscopy assisted (FA) percutaneous kyphoplasty (PKP) in treating single/double segment osteoporotic vertebral compression fracture (OVCF).

METHODS

Patients with single/double segment OVCF receiving either RA or FA PKP were evaluated retrospectively at our spine center from April 2018 to October 2019. The operation time, fluoroscopy frequency, fluoroscopy exposure time, total radiation dose, visual analogue scale (VAS), local kyphosis angle (LKA), height of fractured vertebra (HFV) and complications were compared between the single/double RA group and the FA group.

RESULTS

A total of 96 cases were included in this study, with 59 cases of single segment OVCF and 37 cases of double segment OVCF. For single/double segment OVCF, both RA and FA PKP could relieve pain and reduce fracture. The RA group showed lower fluoroscopy frequency, shorter fluoroscopy exposure time during operation for surgeons, better correction in LKA and HFV, lower rate of cement leakage, but more fluoroscopy frequency, fluoroscopy exposure time and radiation dose for patients compared with the FA group (P < 0.05), while the single RA group showed longer operation time compared with the FA group (P < 0.05).

CONCLUSIONS

For single/double segment OVCF, RA has more advantages in correcting vertebra fracture, reducing intraoperative radiation exposure for surgeons, and reducing the cement leakage rate, but it increases intraoperative radiation for patients compared with FA PKP. And FA has shorter operation time in treating single segment OVCF than RA PKP.

Clinical applications and prospects of 3D printing guide templates in orthopaedics

Background

With increasing requirements for medical effects, and huge differences among individuals, traditional surgical instruments are difficult to meet the patients' growing medical demands. 3D printing is increasingly mature, which connects to medical services critically as well. The patient specific surgical guide plate provides the condition for precision medicine in orthopaedics.

Methods

In this paper, a systematic review of the orthopedic guide template is presented, where the history of 3D-printing-guided technology, the process of guides, and basic clinical applications of orthopedic guide templates are described. Finally, the limitations of the template and possible future directions are discussed.

Results

The technology of 3D printing surgical templates is increasingly mature, standard, and intelligent. With the help of guide templates, the surgeon can easily determine the direction and depth of the screw path, and choose the angle and range of osteotomy, increasing the precision, safety, and reliability of the procedure in various types of surgeries. It simplifies the difficult surgical steps and accelerates the growth of young and mid-career physicians. But some problems such as cost, materials, and equipment limit its development.

Conclusions

In different fields of orthopedics, the use of guide templates can significantly improve surgical accuracy, shorten the surgical time, and reduce intraoperative bleeding and radiation. With the development of 3D printing, the guide template will be standardized and simplified from design to production and use. 3D printing guides will be further sublimated in the application of orthopedics and better serve the patients.

The translational potential of this paper

Precision, intelligence, and individuation are the future development direction of orthopedics. It is more and more popular as the price of printers falls and materials are developed. In addition, the technology of meta-universe, digital twin, and artificial intelligence have made revolutionary effects on template guides. We aim to summarize recent developments and applications of 3D printing guide templates for engineers and surgeons to develop more accurate and efficient templates.

Application of 3-dimensional printing guide template and pointed lotus-style regulator in percutaneous pedicle screw fixation for thoracolumbar fractures

This study aims to analysis the efficacy of the 3D printing percutaneous guide template in combination with the pointed lotus-style regulator in percutaneous pedicle screw fixation. 60 thoracolumbar fractures patients receiving percutaneous pedicle screw fixation (PPSF) were enrolled and randomly divided into 3 groups. Patients in Group A received traditional PPSF, while patients in Group B received PPSF with flat end lotus-style regulator and patients in Group C received PPSF with pointed lotus-style regulator. The experimental results showed that the highest number of pedicle screw successfully inserted by the first time was in group C, while lowest in group A (P < 0.05). The total time of fluoroscopy and operation were lower in group C, and higher in group A (P < 0.05). VAS and ODI scores were all lower after surgery than before surgery in 3groups. VAS and ODI scores were lower in group B and C, compared with group A at day 1, 7 after surgery (P < 0.05). KA decreased significantly in 3 groups after surgery and no difference in KA change between 3 groups (P > 0.05). Taken together, Application of the 3D printing guide template in combination with pointed lotus-style regulator improved the accuracy of pedicle insertion.

Trial registration: ClinicalTrials.gov Identifier: NCT04980131. Registered 18/07/2021.

A comparison of robot-assisted and fluoroscopy-assisted kyphoplasty in the treatment of multi-segmental osteoporotic vertebral compression fractures

Osteoporotic vertebral compression fracture (OVCF) has become a major public health issue that becomes more pressing with increasing global aging. Percutaneous kyphoplasty (PKP) is an effective treatment for OVCF. Robot-assisted PKP has been utilized in recent years to improve accuracy and reduce complications. However, the effectiveness of robot-assisted PKP in the treatment of multi-segmental OVCF has yet to be proved. This study was designed to compare the efficacy of robot-assisted and conventional fluoroscopy-assisted multi-segmental PKP. A total of 30 cases with multi-segmental OVCF between April 2019 and April 2021 were included in this study. Fifteen cases were assigned to the robot-assisted PKP group (robot group) and 15 cases to the conventional fluoroscopy-assisted PKP group (conventional fluoroscopy group). The number of fluoroscopic exposures, fluoroscopic dose, operation time, cement leakage rate, visual analog scale (VAS) score, vertebral kyphosis angle (VKA), and height of fractured vertebral body (HFV) were compared between the 2 groups. The number of fluoroscopic exposures, fluoroscopic doses, and cement leakage rates in the robot group were lower than in the conventional fluoroscopy group (P<0.05) while the operative time in the robot group was longer than in the conventional fluoroscopy group (P<0.05). VAS score and VKA were decreased and HFV was increased after surgery in both groups (P<0.05). Therefore, robot-assisted PKP for the treatment of multi-segmental OVCF can reduce the number of fluoroscopic exposures, fluoroscopic doses, and cement leakage compared to conventional treatment. As such, robot-assisted PKP has good application prospects and is potentially more effective in the treatment of multi-segmental OVCF.

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

BACKGROUND

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.

METHODS

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.

RESULTS

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).

CONCLUSIONS

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.

[Application of Curved Diffusion Needle in unilateral percutaneous vertebroplasty]

Objective

To evaluate the effectiveness of Curved Diffusion Needle in unilateral percutaneous vertebroplasty (PVP) by compared with bilateral PVP.

Methods

A clinical data of 93 patients with osteoporotic vertebral compression fracture (OVCF) treated with PVP between January 2020 and January 2021 was retrospectively analyzed, including 47 patients underwent unilateral PVP assisted with Curved Diffusion Needle (unilateral group) and 46 patients underwent bilateral PVP (bilateral group). There was no significant difference in gender, age, cause of injury, time from injury to operation, T value of bone mineral density, AO classification, distribution of injured vertebrae, and preoperative visual analogue scale (VAS) score, Oswestry disability index (ODI), relative height of injured vertebrae, and Cobb angle between the two groups ( P>0.05). The operation time, the amount of bone cement injection, the incidence of bone cement leakage, the bone cement diffusion distribution, VAS score, ODI, the relative height of injured vertebrae, and Cobb angle were recorded and compared between the two groups.

Results

All operations successfully completed. The operation time was significantly shorter in unilateral group than in bilateral group ( t=-13.936, P=0.000), and the amount of bone cement injection was significantly less in unilateral group than in bilateral group ( t=-13.237, P=0.000). The incidence of bone cement leakage in unilateral group was 19.14%, which was significantly lower than that in bilateral group (39.13%) ( χ ²=4.505, P=0.034). The score of bone cement distribution in unilateral group was 7.0±1.3, of which 41 cases were excellent and 6 cases were well. The score of bilateral group was 7.4±0.8, of which 43 cases were excellent and 3 cases were well. There was no significant difference in score and grading of bone cement distribution between the two groups ( t=-1.630, P=0.107; Z=-1.013, P=0.311). All patients were followed up and the follow-up time was 3-10 months (mean, 6.5 months) in unilateral group and 3-10 months (mean, 6.1 months) in bilateral group. The VAS score, ODI, the relative height of injured vertebrae, and Cobb angle at 24 hours after operation and last follow-up were significantly better than those before operation in the two groups ( P<0.05). There were significant differences in all indicators between 24 hours after operation and last follow-up ( P<0.05). There was no significant difference in all indexes between the two groups ( P>0.05) at the same time point after operation. During follow-up, there was no complication such as contralateral vertebral collapse, refracture, adjacent vertebral fracture, or local kyphosis in the two groups.

Conclusion

Unilateral PVP assisted with Curved Diffusion Needle for OVCF is beneficial to the distribution of bone cement, which can not only achieve similar effectiveness to bilateral PVP, but also achieve shorter operation time, less bone cement injection, and lower risk of bone cement leakage.

[Effectiveness of robot assisted percutaneous kyphoplasty for treatment of single/double-segment osteoporotic vertebral compression fractures]

Objective

To compare the effectiveness of robot assisted and C-arm assisted percutaneous kyphoplasty (PKP) in the treatment of single/double-segment osteoporotic vertebral compression fracture (OVCF).

Methods

The clinical data of 108 cases of single/double-segment OVCF who met the selection criteria between May 2018 and October 2019 were retrospectively analyzed. There were 65 cases of single-segment fractures, of which 38 cases underwent "TiRobot" orthopedic robot-assisted PKP (robot group), 27 cases underwent C-arm X-ray machine fluoroscopy-assisted PKP (C-arm group). There were 43 cases of double-segment fractures, including 21 cases in robot group and 22 cases in C-arm group. There was no significant difference in gender, age, T value of bone mineral density, fracture segment distribution, time from injury to operation, and preoperative visual analogue scale (VAS) score, vertebral kyphosis angle (VKA), and height of fractured vertebra (HFV) in the patients with single/double-segments fractures between robot group and C-arm group ( P>0.05). The operation time, the fluoroscopy frequency of the surgeons and the patient, the fluoroscopy exposure time of the surgeons and the patient, the radiation dose of the C-arm; the VAS scores, VKA, HFV before operation, at 1 day and 6 months after operation; and the complications in the two groups were recorded and compared.

Results

All patients underwent surgery successfully. The operation time of the single-segment robot group was significantly longer than that of the C-arm group ( t=5.514, P=0.000), while the operation time of the double-segment robot group was not significantly different from that of the C-arm group ( t=1.892, P=0.205). The single/double-segment robot group required three-dimensional scanning, so the fluoroscopy frequency, fluoroscopy exposure time, and radiation dose of C-arm received by the patient were significantly higher than those of the C-arm group ( P<0.05); the fluoroscopy frequency and the fluoroscopy exposure time received by the surgeons were significantly less than those of the C-arm group ( P<0.05). There was no infection, embolism, neurological injury, and adjacent segmental fractures. The single/double-segment robot group showed lower rate of cement leakage when compared with the C-arm group ( P<0.05), all the cases of cement leakage happened outside the spinal canal. The VAS score, VKA, and HFV of the single/double-segment robot group and the C-arm group were significantly improved at 1 day and 6 months after operation ( P<0.05), and the VAS score at 6 months after operation was further improved compared with that at 1 day after operation ( P<0.05). At 1 day and 6 months after operation, there was no significant difference in VAS score between the single/double-segment robot group and the C-arm group ( P>0.05). The VKA and HFV of robot group were significantly better than those of the C-arm group ( P<0.05).

Conclusion

For single/double-segment OVCF, robot assisted PKP has more advantages in correcting VKA and HFV, reducing fluoroscopy exposure of surgeons and bone cement leakage rate; C-arm assisted PKP has more advantages in reducing the operation time of single-segment OVCF and fluoroscopy exposure of patients during operation.

A novel "three-dimensional-printed individual guide template-assisted percutaneous vertebroplasty" for osteoporotic vertebral compression fracture: a prospective, controlled study

BACKGROUND

Conventional percutaneous vertebroplasty (PVP) are mainly guided by C-arm fluoroscopy, and it usually leads to excessive X-ray radiation exposure to patients, surgeons, and anesthetists. Moreover, multi-time fluoroscope may prolong the operation time. 3D-printed template could help minimize fluoroscopy shot times and fluoroscopy dosage during operation, and shorten operation time. We perform this study to compare the efficacy and accuracy of PVP assisted by "three-dimensional printed individual guide template" versus conventional PVP.

METHOD

Patients who suffered acute painful single segment osteoporotic vertebral compression fracture(OVCF) needed operative treatment were randomly assigned into three-dimensional printing individual guide template-assisted percutaneous vertebroplasty group (group A) or conventional PVP guided by C-arm fluoroscopy group (group B) at a 1:1 ratio. Fluoroscopy times for puncture points (FTPP), total radiation dosages (TRD), total fluoroscopy time (TFT), and total operation time (TOT) were recorded as the main evaluation factors to evaluate the two operation procedures.

RESULTS

A total of 36 acute painful single segment OVCF patients were successfully operated on, and each group has 18 patients. None of the patients presented symptomatic complications. The surgical success rate in group A was 94.4%(17/18), one patient in the group A was failed and then operated by conventional procedure. FTPP (1.8 ± 0.8 in group A vs 5.2 ± 1.9 in group B, P < 0.05), TRD (4.9 ± 0.9 mGy vs 7.9 ± 1.6 mGy, P < 0.05), TFT (16.7 ± 2.9 vs 26.6 ± 5.3, P < 0.05), and total operation time (19.4 ± 2.4 min vs 27.8 ± 4.0 min, P < 0.05) were presented statistically difference in the two groups. The incidence of cement leakage occurred in group A (3/18, 16.7%) was less than that occurred in group B (7/18, 38.9%) (P > 0.05).

CONCLUSIONS

Compared with the conventional PVP, "three-dimensional-printed individual guide template-assisted PVP" could minimize fluoroscopy shot times during operation and fluoroscopy dosage, shorten operation time, and is a more precise and feasible operation method.

TRIAL REGISTRATION

The present study was registered with the Chinese Clinical Trial Registry (ChiCTR) ( http://www.chictr.org.cn ), and its registration no. is ChiCTR1900024283.

A 3D printed cast for minimally invasive transfer of distal radius osteotomy: a cadaver study

Purpose

In corrective osteotomy of the distal radius, patient-specific 3D printed surgical guides or optical navigation systems are often used to navigate the surgical saw. The purpose of this cadaver study is to present and evaluate a novel cast-based guiding system to transfer the virtually planned corrective osteotomy of the distal radius.

Methods

We developed a cast-based guiding system composed of a cast featuring two drilling slots as well as an external cutting guide that was used to orient the surgical saw for osteotomy in the preoperatively planned position. The device was tested on five cadaver specimens with different body fat percentages. A repositioning experiment was performed to assess the precision of replacing an arm in the cast. Accuracy and precision of drilling and cutting using the proposed cast-based guiding system were evaluated using the same five cadaver arms. CT imaging was used to quantify the positioning errors in 3D.

Results

For normal-weight cadavers, the resulting total translation and rotation repositioning errors were ± 2 mm and ± 2°. Across the five performed surgeries, the median accuracy and Inter Quartile Ranges (IQR) of pre-operatively planned drilling trajectories were 4.3° (IQR = 2.4°) and 3.1 mm (IQR = 4.9 mm). Median rotational and translational errors in transferring the pre-operatively planned osteotomy plane were and 3.9° (IQR = 4.5°) and 2.6 mm (IQR = 4.2 mm), respectively.

Conclusion

For normal weight arm specimens, navigation of corrective osteotomy via a cast-based guide resulted in transfer errors comparable to those using invasive surgical guides. The promising positioning capabilities justify further investigating whether the method could ultimately be used in a clinical setting, which could especially be of interest when used with less invasive osteosynthesis material.

A novel Patient-Specific Three-Dimensional Printing Template Based on External Fixation for Pelvic Screw Insertion

PURPOSE

To investigate the clinical effect of novel patient-specific 3D printing templates based on external fixation for pelvic screw insertion compared with the fluoro-navigation technique.

MATERIALS AND METHODS

We retrospectively studied 18 pelvic fracture patients from July 2017 to July 2018. For analysis, patients were divided into two groups: the template group (15 screws in 8 patients) and the fluoro-navigation group (22 screws in 10 patients). The screw insertion time, radiation exposure time, and accuracy of the screw insertion as evaluated by postoperative CT scans were analyzed.

RESULTS

In the template group, the average screw insertion time (11.5 ± 2.3 min/screw) was significantly 50.6% less than that in the fluoro-navigation group (23.3 ± 3.1 min/screw; P < 0.05). The average time of X-ray exposure in the template group (11.5 ± 3.9 s/screw) was also significantly 39.8% less than in the fluoro-navigation group (19.1 ± 2.5 s/screw; P < 0.05). In the template group, the mean deviation distance and angle between the actual and planned screw position was 2.6 ± 0.2 mm and 2 ± 0.3°.

CONCLUSIONS

The patient-specific template based on external fixation can guide the insertion of the pelvic screw accurately and safely while significantly reducing operation and radiation exposure time.

[Progress in clinical application of 3D printed navigational template in orthopedic surgery]

Orthopedic 3D printed surgical navigational template is an instrument that is prepared by 3D reconstruction based on preoperative radiological data of the patient using computer-aided design (CAD) and 3D printing techniques. The 3D printed navigational template allows accurate intra-operative assessment of the relative spatial distance, angular relationship, direction and depth. The application of 3D printed navigational template technique in orthopedics surgeries achieves the conversion of preoperative planning from 2/3D graphics to 3D models, and provides a new method for individualized and precise treatment. Herein we review the evolution, clinical application, and basic classification of 3D printed navigation template technique, analyze its advantages and disadvantages, and discuss the current problems and the future development of this technique.

Evaluation of a Three-Dimensional Printed Guide and a Polyoxymethylene Thermoplastic Regulator for Percutaneous Pedicle Screw Fixation in Patients with Thoracolumbar Fracture

BACKGROUND This study aimed to evaluate the efficacy of a porous polyoxymethylene thermoplastic regulator combined with a three-dimensional (3D) printed template to guide pedicle needle insertion in patients undergoing percutaneous pedicle screw fixation (PPSF) for thoracolumbar fracture. MATERIAL AND METHODS Forty patients were randomly divided into group A, treated using a porous polyoxymethylene thermoplastic regulator combined with a 3D printed template, and group B, who underwent conventional PPSF. Data recorded included the number of pedicle screws successfully inserted on the first attempt, the number of attempts, the time to successful needle insertion, the total time of fluoroscopy, and the duration of surgery. The Visual Analogue Scale (VAS) and the Oswestry Disability Index (ODI) scores one day before surgery, and at day 1, day 7, month 1, and month 3 after surgery were recorded. The postoperative vertebral posterior kyphotic angle (KA) and the rate of change of KA were recorded. RESULTS Group A had a significantly increased total number of successful first insertions compared with group BV (P<0.05). Postoperative VAS and ODI scores of patients in both groups were significantly lower than before surgery (P<0.05), with no significant difference between the two groups at postoperative month 1 and month 3 (P>0.05). The postoperative vertebral posterior KA decreased significantly in both groups after surgery, with no significant difference between the two groups (P>0.05). CONCLUSIONS The use of a porous polyoxymethylene thermoplastic regulator combined with a 3D printed template may improve the success of pedicle insertion in patients undergoing PPSF.