A novel patient-specific three-dimensional-printed external template to guide iliosacral screw insertion: a retrospective study

Iatrogenic nerve injury following pelvic ring injury: a network meta-analysis

BACKGROUND

Pelvic ring injuries are common in multi-trauma patients and can be life-threatening, necessitating prompt surgical intervention to improve outcomes. However, surgery can lead to complications such as iatrogenic nerve injury. This network meta-analysis aimed to improve outcomes in multi-trauma patients with pelvic ring injuries by evaluating the incidence of iatrogenic nerve injuries, identifying vulnerable nerves, and comparing different fixation methods.

MATERIALS AND METHODS

A systematic search of MEDLINE, EMBASE, and Scopus from inception to 5 December 2023 revealed 29 comparative studies on the incidence of iatrogenic nerve injury in 1561 adult patients with pelvic ring injuries. Data were extracted on study and patient characteristics, iatrogenic nerve injury incidences, and specific nerve injuries. A random-effects model assessed treatment effects, with subgroup analysis and meta-regression. The main outcomes included odds ratios (ORs) and confidence intervals (CIs) for iatrogenic nerve injuries.

RESULTS

Compared with closed reduction internal fixation, robotic-assisted techniques had the highest, and open reduction internal fixation had the lowest ORs for iatrogenic nerve injuries. The robotic-assisted approach ranked best with an OR of 0.22 (95% CI: 0.02-2.16), while closed reduction internal fixation with the anterior approach (OR: 0.71; 95% CI: 0.21-2.48) and open reduction internal fixation with the anterior approach performed the worst. The lateral femoral cutaneous nerve was injured in all open reduction internal fixation with anterior approach procedures and in 66.7% of open reduction internal fixation with posterior approach procedures. Meta-regression showed a significantly lower OR for iatrogenic nerve injuries in patients aged >41.4 years in the open reduction internal fixation with the anterior approach group (OR: 0.02; 95% CI: 0.001-0.63; P  = 0.026) compared with younger patients.

CONCLUSION

The robotic-assisted technique may result in the fewest iatrogenic nerve injuries during the treatment of pelvic ring injuries. The posterior approach may also reduce the risk of iatrogenic nerve injuries.

Clinical applications of 3D printing in spine surgery: a systematic review

PURPOSE

The objective of this systematic review is to present a comprehensive summary of existing research on the use of 3D printing in spinal surgery.

METHODS

The researchers conducted a thorough search of four digital databases (PubMed, Web of Science, Scopus, and Embase) to identify relevant studies published between January 1999 and December 2022. The review focused on various aspects, including the types of objects printed, clinical applications, clinical outcomes, time and cost considerations, 3D printing materials, location of 3D printing, and technologies utilized. Out of the 1620 studies initially identified and the 17 added by manual search, 105 met the inclusion criteria for this review, collectively involving 2088 patients whose surgeries involved 3D printed objects.

RESULTS

The studies presented a variety of 3D printed devices, such as anatomical models, intraoperative navigational templates, and customized implants. The most widely used type of objects are drill guides (53%) and anatomical models (25%) which can also be used for simulating the surgery. Custom made implants are much less frequently used (16% of papers). These devices significantly improved clinical outcomes, particularly enhancing the accuracy of pedicle screw placement. Most studies (88%) reported reduced operation times, although two noted longer times due to procedural complexities. A variety of 3DP technologies and materials were used, with STL, FDM, and SLS common for models and guides, and titanium for implants via EBM, SLM, and DMLS. Materialise software (Mimics, 3-Matic, Magics) was frequently utilized. While most studies mentioned outsourced production, in-house printing was implied in several cases, indicating a trend towards localized 3D printing in spine surgery.

CONCLUSIONS

3D printing in spine surgery, a rapidly growing area of research, is predominantly used for creating drill guides for screw insertion, anatomical models, and innovative implants, enhancing clinical outcomes and reducing operative time. While cost-efficiency remains uncertain due to insufficient data, some 3D printing applications, like pedicle screw drill guides, are already widely accepted and routinely used in hospitals.

[Effectiveness of sacroiliac screw implantation assisted by three-dimensional printed faceted honeycomb guide plate in treatment of posterior pelvic ring fracture]

Objective

To investigate the effectiveness of sacroiliac screw implantation assisted by three-dimensional (3D) printed faceted honeycomb guide plate in the treatment of posterior pelvic ring fracture.

Methods

The clinical data of 40 patients with posterior pelvic ring fractures treated with sacroiliac screw implantation between December 2019 and December 2022 were retrospectively analyzed. Among them, 18 cases were treated with sacroiliac screws fixation assisted by 3D printed faceted honeycomb guide plate (guide plate group), and 22 cases were treated with sacroiliac screws percutaneously fixation under fluoroscopy (conventional group). There was no significant difference in baseline data ( P>0.05) such as gender, age, time from injury to operation, and Dennis classification between the two groups. The implantation time, frequency of C-arm X-ray fluoroscopy, frequency of guide pin adjustment of each sacroiliac screw, and postoperative complications and bone healing were recorded. Majeed score was used to evaluate the functional recovery at 6 months after operation, and CT was used to observe whether the screw penetrated the bone cortex. The deviation between the virtual position and the actual position of the screw tip, the sacral foramen, and the screw entry point was measured on the sagittal CT images of the guide plate group.

Results

The number of screws implanted in S 1 and S 2 vertebral bodies was 14 and 16 respectively in the guide plate group, and 17 and 18 respectively in the conventional group. The implantation time of each sacroiliac screw, the frequency of C-arm X-ray fluoroscopy, and the frequency of guide pin adjustment in S 1, S 2, and all vertebrae in the guide plate group were significantly less than those in the conventional group ( P<0.05). Patients in both groups were followed up 8-48 months, with an average of 19.7 months. There was no incision infection, screw displacement, or internal fixation loosening in both groups. Callus growth was observed in all patients at 12 weeks after operation, and bone healing was achieved in all patients. The healing time ranged from 12 to 24 weeks, with an average of 15.7 weeks. No sacroiliac screw penetrated the bone cortex in the guide plate group; 2 patients in the conventional group had sacroiliac screws penetrating the bone cortex without damaging blood vessels or nerves. In the guide plate group, the deviation between the virtual position and the actual position of the screw tip, the sacral foramen, and the screw entry point were (2.91±1.01), (2.10±0.74), and (1.67±0.70) mm, respectively, with an average deviation of (2.19±1.22) mm. There was no significant difference in Majeed function evaluation between the two groups at 6 months after operation ( P>0.05).

Conclusion

The application of 3D printed faceted honeycomb guide plate in sacroiliac screw implantation for posterior pelvic ring fracture can shorten the screw implantation time, reduce the frequency of fluoroscopy and guide pin adjustment, and reduce the risk of screw penetration through the bone cortex.

Individualized Design Application of 3-Dimensional Printing Navigational Template for Pedicle Screw Installation: A Training Case Report

BACKGROUND The proper installation for pedicle screws by the traditional method of surgeons dependent on experience is not guaranteed, and educational solutions have progressed from chalkboards to electronic teaching platforms. We designed a case of 3-dimensional printing drill guide template as a surgical application, which can accurately navigate implantation of pedicle screws, and assessed its effect for simulative training. MATERIAL AND METHODS We randomly selected a set of computed tomography data for spondylolisthesis. A navigational template of pedicles and screws was designed by software Mimics and Pro-E, where trajectories of directions and angles guiding the nail way were manipulated for screwing based on anatomy, and its solid model was fabricated by a BT600 3D printer. The screws were integrated and installed to observe their stability. RESULTS The navigational model and custom spine implants were examined to be compatibly immobilized, because they are tolerant to radiation and stable against hydrolysis. The screw size and template were fit accurately to the vertebrae intraosseously, because the pilot holes were drilled and the trajectories were guided by cannulas with visible routes. During the surgical workflow, the patient reported appreciation and showed substantial compliance, while having few complications with this approach. Compared with fluoroscopy-assisted or free-hand techniques, the effect of simulative training during processing was excellent. CONCLUSIONS The surgical biomodel is practical for the procedural accuracy of surgical guides or as an educational drill. This fostering a style of "practice substituting for teaching" sets a paragon of keeping up with time and is worthy of recommendation.

Does a novel 3D printed individualized guiding template based on cutaneous fiducial markers contribute to accurate percutaneous insertion of pelvic screws? A preliminary phantom and cadaver study

BACKGROUND

Most 3D-printed guiding templates require dissection of soft tissues to match the corresponding surfaces of the guiding templates. This study sought to explore the accuracy and acceptability of the novel 3D printed individualized guiding templates based on cutaneous fiducial markers in minimally invasive screw placement for pelvic fractures.

METHODS

The printed template was tested on five high-fidelity biomimetic phantom models of the bony pelvis and its surrounding soft tissues as well as on two fresh frozen cadavers. Four cutaneous fiducial markers were transfixed on each phantom model prior to performing CT scans to reconstruct their 3D models. Personalized templates for guiding screw insertion were designed based on the positions of the fiducial markers and virtually planned target screw channels after scanning, followed by 3D printing of the guide. Phase 1 consisted of five expert surgeons inserting one anterograde supra-pubic screw and one sacroiliac screw percutaneously into each phantom model using the 3D-printed guide. The deviation of screw positions between the pre-operative planned and post-operative actual ones was measured after registering their 3D modelling. A Likert scale questionnaire was completed by the expert surgeons to assess their satisfaction and acceptability with the guiding template. Phase 2 consisted of repeating the same procedures on the fresh frozen cadavers in order to demonstrate face, content and concurrent validity.

RESULTS

In Phase 1, all ten screws were successfully implanted with the assistance of the guiding template. Postoperative CT scans confirmed that all screws were safely positioned within the bony pelvic channels without breaching the far cortex. The mean longitudinal deviation at the bony entry point and screw tip between the pre-operative planned and post-operative actual screw paths were 2.83 ± 0.60 mm and 3.12 ± 0.81 mm respectively, with a mean angular deviation of 1.25 ± 0.41°. Results from the Likert questionnaire indicated a high level of satisfaction for using the guiding template among surgeons. In Phase 2, results were similar to those in Phase 1.

CONCLUSIONS

The 3D-printed guiding template based on cutaneous fiducial markers shows potential for assisting in the accurate insertion of percutaneous screws in the pelvis.

Comparison of Computer-Assisted Navigation and 3D Printed Patient-Specific Template for the Iliosacral Screw Placement

BACKGROUND

Iliosacral screw insertion by computer-assisted navigation gradually became the main technique in some hospitals, but the expensive price limited the extensive application. But other techniques such as 3D printed template was used to place iliosacral screw as novel method. This study was to compare the efficiency of percutaneous iliosacral screw placement by using patient-specific template and computer-assisted navigation.

METHODS

Total of 58 patients from September 2017 to September 2021 with sacral injury were treated operatively with percutaneous screw technique, which was selected for this retrospective analysis and divided into two groups (template and computer-assisted navigation). There were 31 patients in template group and 27 patients in computer-assisted navigation group. The surgical details (operation time, blood loss, number of screw placements, and number of fluoroscopies), complications, radiographic and clinical results were recorded. The quality of reduction was assessed by the Matta scoring system. T-test and rank-sum test was used in this study.

RESULTS

Operation time in template group was less (33.97 ± 16.61 < 60.31 ± 11.46 min, p < 0.01), but the preoperative preparation time was more (6.35 ± 1.60 > 5.41 ± 1.58, p < 0.05). The quality of reduction in both groups was no difference (p = 0.352). A patient was complicated with gluteal vessel injury in operation in navigation group, which was treated with ligation, but the same injury was not observed in template group. The related surgical data of patient with gluteal injury was ignored in statistical analysis.

CONCLUSION

Both of the two techniques could improve surgical efficiency, the operation time in template was less than computer-assisted navigation group, but the preoperative preparation time was more.

Complications of conventional percutaneous sacroiliac screw fixation of traumatic pelvic ring injuries: a systematic review and meta-analysis

OBJECTIVES

The objective of this review was to present a thorough overview of the complications associated with conventional percutaneous sacroiliac screw fixation to identify areas for improvement in surgical technique and patient selection.

METHODS

PubMed/Medline, Web of Science, Embase, Ovid, Cochrane library, and Google Scholar were systematically searched for original human studies reporting on complications of conventional percutaneous sacroiliac fixation in traumatic pelvic ring injuries from January 1, 2000, to April 30, 2022. The main meta-analysis was based on the random effect model to pool all complications reported in the included studies. The results were reported as weighted proportions with 95% confidence intervals. This review was conducted in line with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines.

RESULTS

A total of 56 studies with 3644 screws (2871 procedures) met the inclusion criteria, with a mean age of 40.5 years. The most frequently reported complications were screw malposition with a weighted proportion of 6% (95% CI: 5-9%) and involved 189 out of 3644 screws, persistent pain following the procedure with a weighted proportion of 3% (95% CI: 2-4%) and affected 98 out of 2871 patients, and nerve injury, which had a weighted proportion of 2% (95% CI: 1-3%) and was observed in 41 out of 2871 procedures. The L5 and S1 nerve roots were more frequently affected. Revision surgery was required for 184 out of 2871 patients with a weighted proportion of 5% (95% CI: 3-7%). The primary reason for the revision was persistent pain after the initial procedure, which affected 74 out of 184 patients, with a weighted proportion of 2.0% (95% CI: 1.2-2.8%).

CONCLUSIONS

This study showed that screw malposition, the need for revision surgery, persistent pain, and nerve injuries were the most frequent complications following conventional percutaneous sacroiliac screw fixation. However, these results must be interpreted in context due to confounding factors, including the lack of high-quality studies and the absence of uniformity in defining some complications across studies.

Fixation of pelvic acetabular fractures using 3D-printed fracture plates: a cadaver study

Open reduction and internal fixation of pelvic acetabular fractures are challenging due to the limited surgical exposure from surrounding abdominal tissue. There have been a number of recent trials using metallic 3D-printed pelvic fracture plates to simplify and improve various elements of these fracture fixation surgeries; however, the amount of time and accuracy involved in the design and implantation of customised plates have not been well characterised. This study recorded the amount of time related to the design, manufacture and implantation of six customised fracture plates for five cadaveric pelvic specimens with acetabular fracture, while manufacturing, and surgical accuracy was calculated from computed tomography imaging. Five of the fracture plates were designed within 9.5 h, while the plate for a pelvis with a pre-existing fracture plate took considerably longer (20.2 h). Manufacturing comprised 3D-printing the plates in Ti6Al4V with a sintered laser melting (SLM) 3D-printer and post-processing (heat treatment, smoothing, tapping threads). The manufacturing times varied from 27.0 to 32.5 h, with longer times related to machining a thread for locking-head screws with a multi-axis computer numerical control (CNC) mill. For the surface of the plate in contact with the bone, the root-mean-square errors of the print varied from 0.10 to 0.49 mm. The upper range of these errors was likely the result of plate designs that were relatively long with thin cross-sections, a combination that gives rise to high thermal stresses when using a SLM 3D-printer. A number of approaches were explored to control the trajectories of locking or non-locking head screws including guides, printed threads or hand-taps; however, the plate with CNC-machined threads was clearly the most accurate with screw angulation errors of 2.77° (range 1.05-6.34°). The implanted position of the plates was determined visually; however, the limited surgical exposure and lack of intra-operative fluoroscopy in the laboratory led to high inaccuracies (translational errors of 1.74-13.00 mm). Plate mal-positioning would lead to increased risk of surgical injury due to misplaced screws; hence, it is recommended that technologies that can control plate positioning such as fluoroscopy or alignment guides need to be implemented into customised plate design and implantation workflow. Due to the plate misalignment and the severe nature of some acetabular fractures comprising numerous small bone fragments, the acetabular reduction exceeded the clinical limit of 2 mm for three pelvises. Although our results indicate that customised plates are unsuitable for acetabular fractures comprising six or more fragments, confirmation of this finding with a greater number of specimens is recommended. The times, accuracy and suggested improvements in the current study may be used to guide future workflows aimed at producing customised pelvic fracture plates for greater numbers of patients.

A novel biplanar positioning technique to guide iliosacral screw insertion: a retrospective study

PURPOSE

To evaluate the safety and benefits of the biplanar position technique on operative time, radiation exposure, and screw placement accuracy.

METHODS

In this study, we retrospectively evaluated the records of 64 patients with pelvic fractures (Tile B and C) between October 2020 and September 2021. According to the surgical methods selected by the patients, the patients were divided into a biplanar positioning technique group (biplanar group), a Ti-robot navigation group (Ti-robot group), and a traditional fluoroscopy-guided technique group (traditional group). Length of operation, blood loss, intra-operative radiation exposure fracture reduction, and the quality of screw positioning were compared among the three groups.

RESULTS

One hundred three screws were implanted in 64 patients (biplanar group 22, Ti-robot group 21, traditional group 21). The average operation time was significantly less in the biplanar group (26.32 ± 6.32 min) than in the traditional group (79.24 ± 11.31 min), but significantly more than in the Ti-robot group (15.81 ± 3.9 min). The radiation exposure was similar in the biplanar group (740.53 ± 185.91 cGy/cm2) and Ti-robot group (678.44 ± 127.16 cGy/cm2), both of which were significantly more than in the traditional group (2034.58 ± 494.54 cGy/cm2). The intra-operative blooding loss was similar in the biplanar group (12.76 ± 3.77 mL) and the Ti-robot group (11.92 ± 4.67 mL), both of which were significantly less than in the traditional group (29.7 ± 8.01 mL). The Screw perforation was slightly lower in the biplanar group (94.1%) than in the Ti-robot group (97.2%) but was significantly higher than in the traditional group (75.7%).

CONCLUSIONS

The biplanar positioning technique is as accurate and safe as computer-navigated systems for percutaneous iliosacral screw insertion, associated with shorter surgical time, lower intra-operative radiation exposure, and more accuracy compared to traditional fluoroscopy.

Three-Dimensional Printing and Fracture Mapping in Pelvic and Acetabular Fractures: A Systematic Review and Meta-Analysis

Three-dimensional printing and fracture mapping technology is gaining popularity for preoperative planning of fractures. The aim of this meta-analysis is to further understand for the effects of 3D printing and fracture mapping on intraoperative parameters, postoperative complications, and functional recovery on pelvic and acetabular fractures. The PubMed, Embase, Cochrane and Web of Science databases were systematically searched for articles according to established criteria. A total of 17 studies were included in this study, of which 3 were RCTs, with a total of 889 patients, including 458 patients treated by traditional open reduction and internal fixation methods and 431 patients treated using 3D printing strategies. It was revealed that three-dimensional printing and fracture mapping reduced intraoperative surgical duration (RoM 0.74; 95% CI; 0.66–0.83; I² = 93%), and blood loss (RoM 0.71; 95% CI; 0.63–0.81; I² = 71%). as compared to traditional surgical approaches. In addition, there was significantly lower exposure to intraoperative imaging (RoM 0.36; 95% CI; 0.17–0.76; I² = 99%), significantly lower postoperative complications (OR 0.42; 95% CI; 0.22–0.78; I² = 9%) and significantly higher excellent/good reduction (OR 1.53; 95% CI; 1.08–2.17; I² = 0%) in the three-dimensional printing and fracture mapping group. Further stratification results with only prospective studies showed similar trends. Three-dimensional printing and fracture mapping technology has potential in enhancing treatment of complex fractures by improving surgical related factors and functional outcomes and therefore could be considered as a viable tool for future clinical applications.

The novel infra-pectineal buttress plates used for internal fixation of elderly quadrilateral surface involved acetabular fractures

Objectives

In geriatric acetabular fractures, the quadrilateral surface (QLS) was frequently involved in acetabular fracture patterns and accompanied by medial displacement. It was important to buttress the medial displaced QLS and reconstruct the congruity of the affected acetabulum. To evaluate the clinical effectiveness of the novel infra‐pectineal quadrilateral surface buttress plates for the treatment of geriatric acetabular fractures.

Methods

Twenty‐three geriatric patients who were treated for acetabular fractures involving QLS with the novel infra‐pectineal buttress plates (NIBP) through a single supra‐ilioinguinal approach between January 2015 and June 2019 were retrospectively analyzed; all patients received at least 1 year's follow‐up. All patients were aged ≥60 years old and including 18 males and five females. Radiologic and clinical outcomes of patients involved in the study were collated and analyzed according to the Matta scoring system and the Merle D'Aubigné–Postel scoring system. The functional recovery scoring was compared using q‐test.

Results

All 23 consecutive patients had relatively satisfactory clinical treatment effectiveness. Average ages, length of incision, operation time, and intraoperative blood loss were 69.8 ± 6.1 years, 12.1 ± 2.6 cm, 166.5 ± 43.5 min, and 500 (500,700) ml, respectively. According to the Matta scoring system, 14 cases of reduction were graded as excellent, five as good, and four as fair. At the last follow‐up, the clinical outcome evaluation was excellent in 13 cases, good in seven cases, and poor in three cases with the use of the Merle D'Aubigné–Postel scoring system. The difference of modified Merle D'Aubigne‐Postel score at 3 months, 6 months and last follow up was statistically significant (F = 21.56, p < 0.05). Postoperative lateral femoral cutaneous nerve injury occurred in three patients and heterotopic ossification occurred in one patient.

Conclusions

For the treatment of geriatric acetabular fractures, the NIBP could provide stable and effective fixation to the QLS involved acetabular fractures, and related satisfactory clinical results with few complications were noted.

Iliosacral screw fixation of pelvic ring disruption with tridimensional patient-specific template guidance

INTRODUCTION

Posterior pelvic ring disruption includes sacral fractures, sacroiliac joint fracture dislocations and ilium fractures. Percutaneous iliosacral screw fixation of sacral fractures and sacraoiliac joint fracture dislocations have been prevailing, it has the advantages of minimal invasiveness, less blood loss and low wound infection rate.

HYPOTHESIS

This study was to evaluate the application of three-dimensional (3D) printed patient-specific guide template in closed reduction and iliosacral screw fixation of posterior pelvic ring disruption.

MATERIAL AND METHODS

The data of patients, who were treated with closed reduction and iliosacral screw fixation of posterior pelvic ring disruption with the assistance of 3D printed guide template from December 2014 to September 2018, were collected. The screw placement time, fluoroscopy time, intraoperative blood loss, fracture reduction, screw position, and functional assessment were recorded.

RESULTS

There were 17 cases of unstable pelvic fractures,and 20 screws were inserted for fixation of sacral fractures or sacroiliac joint dislocations, with bilateral screw placement in 3 cases. The average time for each screw placement was 45.9±8.6min (30-60min). The average fluoroscopy time for each screw insertion was 50.3±19.7s (24-96 s). The mean blood loss for each screw placement was 32.0±11.1ml (20-50ml). According to Matta scale, the fracture reduction was graded as excellent in all the 17 cases. According to the modified Gras classification, the 3D CT reconstruction of the pelvis demonstrated Grade 1 for 18 screws and Grade 2 for 2 screw. Functional outcome 1 year postoperatively was rated as 15 excellent and 2 good, according to the Majeed functional scale.

DISCUSSION

It is feasible and safe to stabilize the posterior pelvic ring disruption using iliosacral screw fixation under assistance of the 3D printed guide template. It could reduce fluoroscopy time, screw placement time and intraoperative blood loss and achieve good postoperative recovery.

LEVEL OF PROOF

IV; Retrospective study.

Screw misplacement in percutaneous posterior pelvic iliosacral screwing with and without navigation: A prospective clinical study of 174 screws in 127 patients

BACKGROUND

Recent studies of iliosacral screw fixation performed using intraoperative navigation systems have shown promising results. The Surgivisio Platform is a new-generation three-dimensional intraoperative navigation tool that has been used at our institution for 2years. The aim of this prospective study was to assess the contribution of navigation in terms of iliosacral screw positioning accuracy and of radiation exposure, by comparing outcomes with vs. without navigation.

HYPOTHESIS

Navigation allows more accurate percutaneous iliosacral screw positioning regardless of the type of screw fixation (with sacral dysmorphism and/or cemented screw fixation and/or multiple screw fixation).

MATERIALS AND METHODS

Between January 2018 and December 2019, consecutive patients who underwent percutaneous iliosacral screw fixation of pelvic ring fractures without vertical instability were included in this single-centre prospective study. Screw position accuracy was evaluated by postoperative high-resolution computed tomography (HRCT). Operative time, radiation dose, and complications were recorded.

RESULTS

We included 127 patients with 174 iliosacral screws, of which 129 were positioned under fluoroscopic guidance and 45 using navigation. According to the modified Gras classification, 7% (12/174) of the screws were incorrectly positioned and 2% (4/174) required repositioning. The frequency of screw malposition was not significantly different between the fluoroscopy and navigation groups (8.5%, 11/129 vs. 2.2%, 1/45, respectively; p=0.19). However, screw position in dysmorphic sacra was significantly better with navigation (p=0.04), whereas no significant difference in final screw position was found for cemented or multiple screw implantations. In the navigation group, the operative time was significantly longer (28.2min vs. 21.6min, p=0.003), and the mean dose-area product significantly greater (6.6Gy·cm² vs. 4.9Gy·cm², p=0.02). The complication rates were not different between the two groups.

CONCLUSION

In patients who have pelvic ring fractures without vertical instability, navigation of percutaneous iliosacral screw placement using the Surgivisio Platform improves screw positioning in dysmorphic sacra, at the cost of a longer operative time and greater radiation exposure of the patient.

LEVEL OF EVIDENCE

II, prospective study.

Three-Dimensional Printing of Medical Devices Used Directly to Treat Patients: A Systematic Review

Until recently, three-dimensional (3D) printing/additive manufacturing has not been used extensively to create medical devices intended for actual clinical use, primarily on patient safety and regulatory grounds. However, in recent years there have been advances in materials, printers, and experience, leading to increased clinical use. The aim of this study was to perform a structured systematic review of 3D-printed medical devices used directly in patient treatment. A search of 13 databases was performed to identify studies of 3D-printed medical devices, detailing fabrication technology and materials employed, clinical application, and clinical outcome. One hundred and ten papers describing one hundred and forty medical devices were identified and analyzed. A considerable increase was identified in the use of 3D printing to produce medical devices directly for clinical use in the past 3 years. This is dominated by printing of patient-specific implants and surgical guides for use in orthopedics and orthopedic oncology, but there is a trend of increased use across other clinical specialties. The prevailing material/3D-printing technology used were titanium alloy/electron beam melting for implants, and polyamide/selective laser sintering or polylactic acid/fused deposition modeling for surgical guides and instruments. A detailed analysis across medical applications by technology and materials is provided, as well as a commentary regarding regulatory aspects. In general, there is growing familiarity with, and acceptance of, 3D printing in clinical use.

Does 3D-Assisted Operative Treatment of Pelvic Ring Injuries Improve Patient Outcome?-A Systematic Review of the Literature

Background: There has been an exponential growth in the use of advanced technologies for three-dimensional (3D) virtual pre- and intra-operative planning of pelvic ring injury surgery but potential benefits remain unclear. The purpose of this study was to evaluate differences in intra- and post-operative results between 3D and conventional (2D) surgery. Methods: A systematic review was performed including published studies between 1 January 2010 and 22 May 2020 on all available 3D techniques in pelvic ring injury surgery. Studies were assessed for their methodological quality according to the Modified McMaster Critical Review form. Differences in operation time, blood loss, fluoroscopy time, screw malposition rate, fracture reduction and functional outcome between 3D-assisted and conventional (2D) pelvic injury treatment were evaluated and a best-evidence synthesis was performed. Results: Eighteen studies fulfilled the inclusion criteria, evaluating a total of 988 patients. Overall quality was moderate. Regarding intra-operative results of 3D-assisted versus conventional surgery: The weighted mean operation time per screw was 43 min versus 52 min; for overall operation time 126 min versus 141 min; blood loss 275 ± 197 mL versus 549 ± 404 mL; fluoroscopy time 74 s versus 125 s and fluoroscopy frequency 29 ± 4 versus 63 ± 3. In terms of post-operative outcomes of 3D-assisted versus conventional surgery: weighted mean screw malposition rate was 8% versus 18%; quality of fracture reduction measured by the total excellent/good rate by Matta was 86% versus 82% and Majeed excellent/good rate 88% versus 83%. Conclusion: The 3D-assisted surgery technologies seem to have a positive effect on operation time, blood loss, fluoroscopy dose, time and frequency as well as accuracy of screw placement. No improvement in clinical outcome in terms of fracture reduction and functional outcome has been established so far. Due to a wide range of methodological quality and heterogeneity between the included studies, results should be interpreted with caution.

Are the common sterilization methods completely effective for our in-house 3D printed biomodels and surgical guides?

INTRODUCTION

In-hospital 3D printing is being implemented in orthopaedic departments worldwide, being used for additive manufacturing of fracture models (or even surgical guides) which are sterilized and used in the operating room. However, to save time and material, prints are nearly hollow, while 3D printers are placed in non-sterile rooms. The aim of our study is to evaluate whether common sterilization methods can sterilize the inside of the pieces, which would be of utmost importance in case a model breaks during a surgical intervention.

MATERIAL AND METHOD

A total of 24 cylinders were designed and printed with a 3D printer in Polylactic Acid (PLA) with an infill density of 12%. Manufacturing was paused when 60% of the print was reached and 20 of the cylinders were inoculated with 0.4 mL of a suspension of S epidermidis ATTCC 1228 in saline solution at turbidity 1 McFarland. Printing was resumed, being all the pieces completely sealed with the inoculum inside. Posteriorly, 4 groups were made according to the chosen sterilization method: Ethylene Oxide (EtO), Gas Plasma, Steam Heat or non-sterilized (positive control). Each group included 5 contaminated cylinders and 1 non-contaminated cylinder as a negative control. After sterilization, the inside of the cylinders was cultured during 7 days.

RESULTS

We observed bacterial growth of just a few Forming Colony Units (FCU) in 4 out of 5 positive controls and in 2 out of 5 contaminated cylinders sterilized with Gas Plasma. We could not assess any bacterial growth in any of the EtO or Steam Heat samples or in any of the negative controls. Pieces sterilized under Steam Heat resulted completely deformed.

CONCLUSIONS

High temperatures reached during the procedure of additive manufacturing can decrease the bacterial load of the biomodels. However, there is a potential risk of contamination during the procedure. We recommend sterilization with EtO for in-hospital 3D-printed PLA hollow biomodels or guides. Otherwise, in case of using Gas Plasma, an infill of 100% should be applied.

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.

A feasibility study of individual 3D-printed navigation template for the deep external fixator pin position on the iliac crest

Background

The aim of this study was to investigate the feasibility of an individual navigation template for the deep pin position on the iliac crest, based on digital design and 3D printing technology.

Methods

The preoperative CT images of 8 patients with pelvic fractures were collected. The data were reconstructed using a 3D imaging reconstruction workstation. An individual navigation template for the deep pin position on the iliac crest was designed on a virtual 3D model. The individual drill template and the solid pelvic model were produced using the 3D printing technology. The individual drill template was used for intraoperative deep pin position on the iliac crest after the preoperative simulation was completed.

Results

Thirty-two external fixator pins were inserted using the individual drill template. The average depth of pins was 84.82 mm. The trajectories were appropriate based on the postoperative X-ray and CT scan. No significant difference in the entry point, convergence angle, and caudal angle of the pins were noted before and after the operation (all P > 0.05). Finite element analysis indicated that the deep external fixator pin position could more reasonably distribute the stress in the cortical and spongy bones in the pelvis. All patients could perform partial weight-bearing activity 6 weeks postoperatively. No loosening and rupture of the pin, infection, and no damage of blood vessels and nervous tissue were found during the entire follow-up period.

Conclusions

The individual drill template technique is an improvement of the traditional technique, which could increase precision and the depth of pin position. In addition, good mechanical stability and low risk of pin-related complications occurred due to the individual drill template, which makes the external fixation technique a potential alternative.

Do three-dimensional modeling and printing technologies have an impact on the surgical success of percutaneous transsacral screw fixation?

Objectives

This study aims to determine the role of computed tomography (CT)-derived templates, produced by three- dimensional (3D) modeling, image processing and printing technology, in percutaneous transsacral screw fixation and evaluate the effects of their use on surgical success.

Materials and methods

This prospective study conducted between June 2018 and December 2019 utilized 15 composite pelvis models for transsacral-transiliac screw fixation. For the procedure, modeled templates were utilized for wiring on the left side of the pelvis models, while the conventional method was performed on the right side of the pelvis models. In the computed tomography images acquired after wiring, appropriate wire position was evaluated.

Results

The placed wires held the S1 body appropriately in all of the procedures with or without template use. With the template use, the wires were placed appropriately in the surgical bone corridor suitable for the transsacral-transiliac screw fixation in all of the models. However, with the conventional methods, the wires were not placed in the safe surgical bone corridor in four models. The wire deviation angle in the axial plane was significantly lower in the template group (p=0.001), whereas it was not different between the template group and the conventional method group in the coronal plane (p=0.054). The amount of deviation from the ideal wire entry site was significantly reduced in the template group compared to the conventional method group (p=0.001).

Conclusion

With the use of 3D modeling and printing technology, CT-derived templates can be produced and utilized for transsacral screw fixation procedures and their use increases surgical success by reducing the surgical margin of error.

Sacral fractures: issues, challenges, solutions

Sacral fractures are a heterogeneous group of fractures occurring in young people following road traffic accidents and falls from height, or in the elderly with osteoporosis following trivial trauma.This heterogeneity, combined with the low incidence of sacral fractures, determines a lack of experience amongst physicians, often leading to misdiagnosis, underestimation and inadequate treatment. The diagnosis should be made by assessing specific features during the clinical presentation, while computed tomography (CT) scan continues to be the choice of investigation.Sacral fractures can be treated non-operatively or surgically. Non-operative treatment is based on rest, pain relief therapy and early mobilization as tolerated. Surgical techniques can be split into two main groups: posterior pelvic fixation techniques and lumbopelvic fixation techniques. Anterior pelvic fixation techniques should be considered when sacral fractures are associated with anterior pelvic ring injuries, in order to increase stability and reduce the risk of posterior implant failure. To improve fracture reduction, different solutions could be adopted, including special positioning of the patient, manipulation techniques and use of specific reduction tools. Patients suffering from spinopelvic dissociation with associated neurologic lesions hardly ever recover completely, with residual lower-limb neurologic sequelae, urinary problems and sexual disfunction.Herein, we present issues, challenges and solutions related to the management of sacral fractures. Cite this article: EFORT Open Rev 2020;5:299-311. DOI: 10.1302/2058-5241.5.190064.

Combined 3D Printed Template to Guide Iliosacral Screw Insertion for Sacral Fracture and Dislocation: A Retrospective Analysis

Objective

To evaluate the accuracy and safety of a combined 3D printed guide template (combined template) to assist iliosacral (IS) screw placement for sacral fracture and dislocation.

Methods

A total of 37 patients, 24 men and 13 women, age from 22 to 68 years old, diagnosed with a sacral fracture and dislocation were involved in this study for retrospective analysis from January 2016 to February 2018. There were 19 patients in the template group (42 screws) and 18 patients in the conventional group (31 screws). In the combined template group, IS screw placement was assisted by a combined 3D printed template; in the conventional group, the IS screws were placed freehand under fluoroscopy. The accuracy of the IS screw placement was evaluated by comparing the screw angle and the location of the screw entry point between the actual and the simulated screw in the combined template group. The safety of the IS screw placement was evaluated by comparing the quality of the reduction, the grading of the screws, the operation time, and radiation exposure times between groups.

Results

A total of 73 pedicle screws were placed in 37 patients: 42 screws (30 S1, 12 S2) in the combined template group and 31 screws (23 S1, 8 S2) in the conventional group. In the conventional group, 1 patient developed symptoms of L5 nerve stimulation. In the combined template group, the average operative time of each screw was 25.01 ± 2.90 min, with average radiation exposure times of 12.05 ± 4.00. In the conventional group, the average operative time of each screw was 46.24 ± 9.59 min, with an average radiation exposure time of 56.10 ± 6.75. There were significant differences in operation and radiation exposure times between groups. The rate of screw perforation was lower in the combined template group (2 of 42 screws, 0 at grade III and 2 at grade II) than in the conventional group (5 of 38 screws, 2 at grade III and 3 at grade III). In the combined template group, the mean distance between the entry points of the actual and simulated screws was 1.4 ± 0.9 mm, with a mean angle of deviation of 2.1° ± 1.6°. All patients were followed up once every 3 months and were followed for 3 to 12 months.

Conclusion

Using the combined template to assist with the insertion of IS screws delivered good accuracy, less fluoroscopy and shorter operation time, and avoided neurovascular injury as a result of screw malposition.

Minimally Invasive Screw Fixation of Unstable Pelvic Fractures Using the "Blunt End" Kirschner Wire Technique Assisted by 3D Printed External Template

Objective

This study aimed to determine the accuracy and safety of the “blunt end” Kirschner wire (KW) technique for the minimally invasive treatment of unstable pelvic fractures with the assistance of a 3D printed external template.

Methods

Clinical data of 28 patients with unstable pelvic fractures between January 2016 and January 2018 were retrospectively analyzed. There were 6 cases of B1, 10 of B2, 8 of C1, and 4 of C2 fractures, all of which received surgical treatment. The “blunt end” KW technique with a 3D template was adopted for the minimally invasive placement of the iliosacral (IS) or superior ramus screws. The number of intraoperative fluoroscopies, surgical time, and complications were recorded. Postoperative reduction was assessed using the Matta criteria, and the Majeed score system was used to evaluate postoperative functional recovery.

Results

The average number of fluoroscopies was 35 per patient, and the average surgical time was 85.2 min. A total of 19 S1 and 28 S2 IS screws were inserted. Eleven antegrade superior ramus screws and 4 retrograde screws were placed in 11 patients, and anterior subcutaneous internal fixation (INFIX) was used to fix the anterior pelvic ring in 17 patients. All patients were followed up for an average of 18 months. Postoperative reduction was evaluated by Matta's criteria: excellent in 16 cases, good in 9 cases, and fair in 3 cases. The Majeed score was used in the last follow-up to evaluate functional recovery: excellent in 13 cases, good in 10 cases, fair in 4 cases, and poor in 1 case. There were no cases of operative vascular injury.

Conclusion

The “blunt end” KW technique with a 3D printed external template is a safe and effective method for the placement of IS and superior ramus screws in unstable pelvic fractures with minimized surgical duration and radiation exposure.