Evaluation of 2D and 3D navigation for iliosacral screw fixation

Use of 3D Navigation Versus Traditional Fluoroscopy for Posterior Pelvic Ring Fixation

Unstable pelvic ring disruption is most commonly treated with closed reduction and percutaneous screw fixation. Traditional methods involve screw placement under fluoroscopic imaging, but with recent technologic advances, intraoperative 3D navigation can now be used to help with the insertion of sacroiliac screws. Various cadaver studies have shown that placement of sacroiliac screws under 3D navigation is more accurate than placement under traditional fluoroscopic guidance. This retrospective review of 134 patients evaluated the clinical use of 3D navigation vs traditional fluoroscopy for sacroiliac screw insertion at an urban level I trauma center. Analysis of surgical data showed a significantly longer imaging time with the conventional method compared with the more experimental 3D navigation (204.06 seconds vs 66.90 seconds, P<.01). Further, a significantly larger radiation dose to both the patient and the staff was seen with traditional fluoroscopy (80.1 mGy for each) compared with that of 3D navigation (39.0 mGy and 25.1 mGy, respectively). No statistically significant difference was seen for outcome or follow-up variables between the 2 extrapolated groups. These variables included length of hospital stay, infection, nerve injury, and hardware breakage. The authors advocate that 3D navigated sacroiliac screws are safe and effective for pelvic ring stabilization; this method may be especially applicable in certain difficult imaging situations, such as morbid obesity, bowel gas interference, and overlapping pelvic structures that make the sacral corridor difficult to discern with traditional 2D fluoroscopy. Safe placement of transiliac-transsacral screws (P<.01) occurred with 3D navigation, and there was a statistically significant increase in adequate screw placement in multiple sacral segments compared with single-level stabilization (P<.01). [Orthopedics. 2021;44(4):229-234.].

Current Minimally Invasive Surgical Concepts for Sacral Insufficiency Fractures

An increasing incidence of sacral insufficiency fractures in geriatric patients has been documented, representing a major challenge to our healthcare system. Determining the accurate diagnosis requires the use of sectional imaging, including computed tomography and magnetic resonance imaging. Initially, non-surgical treatment is indicated for the majority of patients. If non-surgical treatment fails, several minimally invasive therapeutic strategies can be used, which have shown promising results in small case series. These approaches are sacroplasty, percutaneous iliosacral screw fixation (S1 with or without S2), trans-sacral screw fixation or implantation of a trans-sacral bar, transiliac internal fixator stabilisation, and spinopelvic stabilisation. These surgical strategies and their indications are reported in detail. Generally, treatment-related decision making depends on the clinical presentation, fracture morphology, and attending surgeon's experience.

Utility of 3-Dimensional Intraoperative Imaging in Pelvic and Acetabular Fractures: A Network Meta-Analysis

BACKGROUND

Successful surgical management of pelvic ring and acetabular fractures requires technical expertise to achieve an accurate reduction and stable fixation. The use of 3-dimensional (3D) intraoperative imaging (3DIOI) as an assessment tool has led to improved reduction and placement of implants. The purpose of this study was to assess the utility of using 3DIOI in the management of acetabular and pelvic fractures on the basis of outcomes reported in the literature.

METHODS

A literature search was performed using PubMed, the Cochrane Database of Systematic Reviews (CDSR), and Google Scholar using key terms. A network meta-analysis conducted using the frequentist approach allowed for statistical analysis of reported outcomes regarding screw position (in mm), fracture reduction (in mm), and complications.

RESULTS

A total of 9 studies were included in this analysis. When compared with conventional radiography, the mean radiation dose (in cGy·cm2) was significantly higher in 3DIOI (mean difference, 82.72; 95% confidence interval [CI], 21.83 to 143.61; p = 0.007). Use of 3DIOI yielded a 93% lower risk of developing medical complications (odds ratio [OR], 0.07; 95% CI, 0.02 to 0.35; p = 0.014). Use of 3DIOI yielded higher odds of achieving accurate screw placement (OR, 4.21; 95% CI, 1.44 to 12.32; p = 0.008) and perfect reduction (OR, 2.60; 95% CI, 1.19 to 5.68; p = 0.016). In ranking the imaging modalities, 12 of the 13 parameters analyzed were in favor of 3DIOI over conventional fluoroscopy and 2D navigation imaging.

CONCLUSIONS

Current literature supports the use of 3DIOI because of the decreased rates of misplaced implants, malreduced fractures, complications, and subsequent revision operations. The use of 3DIOI allows for improved visualization of pelvic anatomy when repairing pelvic and acetabular fractures, and helps surgeons to achieve favorable surgical outcomes.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Treating sacroiliac joint dislocation through percutaneous sacroiliac screw fixation with the aid of 2 fluoroscopes: a novel technique

Background

Percutaneous sacroiliac screw fixation is the standard treatment for sacroiliac joint (SIJ) dislocation. In most hospitals, the procedure is guided by a C-arm X-ray fluoroscopy system, which must be repeatedly repositioned during surgery. In this study, we investigated the feasibility of using 2 fluoroscopes simultaneously.

Methods

A total of 28 consecutive patients with SIJ dislocation were included in this study. The patients were randomly allocated to groups and underwent percutaneous sacroiliac screw fixation using either 1 or 2 fluoroscopes. Total radiation exposure frequency, radiation dose, and operation time were recorded and compared. Dislocation reduction quality was assessed using the Tornetta and Matta standard, and the Majeed functional score was used to evaluate clinical, imaging, and social function following pelvic injury. Complications were also recorded.

Results

The results showed that the radiation exposure frequency was significantly less with 2 fluoroscopes than with a single fluoroscope (21.5±8.6 and 42.6±18.3 times, respectively; P<0.001). However, the radiation dose (156.3±67.2 mGy for 1 fluoroscope and 157.8±38.2 mGy for 2 fluoroscopes; P>0.05) between the 2 groups was not significantly different. The total operation time was also significantly shorter with 2 fluoroscopic devices than with a single device (35.8±12.9 and 65.5±19.7 minutes, respectively; P<0.001). The dislocation reduction quality and Majeed functional score (92.3% and 86.7% for 1 fluoroscope, 93.3% and 84.6% for 2 fluoroscopes, respectively; P>0.05) did not differ significantly between the 2 groups at the final follow-up. Complications, such as pain, superficial infection, restricted squatting, limp, and screw failure, were rarely recorded in either group.

Conclusions

The simultaneous application of 2 fluoroscopes is highly appropriate during percutaneous sacroiliac screw fixation to treat SIJ dislocation, and can significantly reduce radiation exposure frequency and operation time.

O-arm navigation for sacroiliac screw placement in the treatment for posterior pelvic ring injury

PURPOSE

This study aims to investigate the application value of O-arm navigation system in sacroiliac screw placement for the treatment of unstable pelvic ring injury.

METHODS

A total of 40 patients (mean age = 30.75 ± 14.99 years, 25 males, 15 females) were included. From January 2016 to July 2018, 40 patients with posterior pelvic ring injury treated in our hospital were included. Of them, 19 patients underwent O-arm navigation for screw placement (O-arm group) while the other 21 received C-arm fluoroscopy guidance (C-arm group) for sacroiliac screw placement. Intraoperative outcomes and the outcome of screw placement were compared between groups. The quality of radiological images was assessed by Matta's radiological outcome grade. The outcome of complex pelvic fracture treatment was evaluated by Majeed Functional score.

RESULTS

All demographic and clinical characteristics were comparable between the two groups. Compared with the C-arm groups, the O-arm group had a shorter surgery time (33.19 ± 3.14 vs. 48.35 ± 4.38 min, P < 0.001), a higher overall good outcome "excellent + good" rate of screw placement (95.45% vs. 73.91%, P < 0.05), and a significantly higher Majeed Functional score better outcome of complex pelvic fracture treatment at 1 and 3 months postoperation (both P < 0.05).

CONCLUSION

Our results demonstrated that O-arm navigation system is feasible and safe for the treatment of posterior pelvic ring injury and can effectively improve the accuracy and safety of sacroiliac screw placement, shorten the operation time, and help rapid postoperative functional recovery.

A real time image-guided reposition system for the loosed bone graft in orthognathic surgery

In traditional orthognathic surgery, the dental splint technique is typically used to assist surgeons to reposition the maxilla or mandible. However, the design and manufacturing of dental splints is time-consuming and labor-intensive, and the templates may not applicable for some complicated cases due to the anatomic intricacies in the maxillofacial region. During recent years, computer-aided navigation technology has been widely used in oral and maxillofacial surgery. However, due to the limitation of current calibration and registration methods, it has been rarely reported for the motion tracking of intraoperative reposition for the loosed bone graft. In this study, a novel surgical navigation system was developed. With the use of this system, not only the surgical saw can be tracked in real-time, but also the loosed bone graft can be navigated under the guidance of the interactive 2D and 3D views until it is aligned with the preoperatively planned position. The phantom experiments validated the feasibility of our surgical navigation system, and the mean error of image-guided reposition was 1.03 ± 0.10 mm, which was significantly more accurate than the mean error of 5.57 ± 1.40 mm based on the non-navigated methods.

Computer-Assisted Orthopedic and Trauma Surgery

BACKGROUND

There are many ways in which computer-assisted orthopedic and trauma surgery (CAOS) procedures can help surgeons to plan and execute an intervention.

METHODS

This study is based on data derived from a selective search of the literature in the PubMed database, supported by a Google Scholar search.

RESULTS

For most applications the evidence is weak. In no sector did the use of computer-assisted surgery yield any relevant clinical or functional improvement. In trauma surgery, 3D-navigated sacroiliac screw fixation has become clinically established for the treatment of pelvic fractures. One randomized controlled trial showed a reduction in the rate of screw misplacement: 0% with 3D navigation versus 20.4% with the conventional procedure und 16.6% with 2D navigation. Moreover, navigation-assisted pedicle screw stabilization lowers the misplacement rate. In joint replacements, the long-term results showed no difference in respect of clinical/functional scores, the time for which the implant remained in place, or aseptic loosening.

CONCLUSION

Computer-assisted procedures can improve the precision of certain surgical interventions. Particularly in joint replacement and spinal surgery, the research is moving away from navigation in the direction of robotic procedures. Future studies should place greater emphasis on clinical and functional results.

Comparing the Efficiency, Radiation Exposure, and Accuracy Using C-Arm versus O-Arm With 3D Navigation in Placement of Transiliac-Transsacral and Iliosacral Screws: A Cadaveric Study Evaluating an Early Career Surgeon

OBJECTIVES

To compare the efficiency, radiation exposure to surgeon and patient, and accuracy of C-arm versus O-arm with navigation in the placement of transiliac-transsacral and iliosacral screws by an orthopaedic trauma fellow, for a surgeon early in practice.

METHODS

Twelve fresh frozen cadavers were obtained. Preoperative computed tomography scans were reviewed to assess for safe corridors in the S1 and S2 segments. Iliosacral screws were assigned to the S1 segment in dysmorphic pelvises. Screws were randomized to modality and laterality. An orthopaedic trauma fellow placed all screws. Time of procedure and radiation exposure to the cadaver and surgeon were recorded. Three fellowship-trained orthopaedic trauma surgeons rated the safety of each screw on postoperative computed tomography scan.

RESULTS

Six normal and 6 dysmorphic pelvises were identified. Eighteen transiliac-transsacral screws and 6 iliosacral screws were distributed evenly between C-arm and O-arm. Average operative duration per screw was significantly shorter using C-arm compared with O-arm (15.7 minutes ± 6.1 vs. 23.7 ± 8.5, P = 0.014). Screw placement with C-arm exposed the surgeon to a significantly greater amount of radiation (3.87 × 10 rads vs. 0.32 × 10, P < 0.001) while O-arm exposed the cadaver to a significantly greater amount of radiation (0.03 vs. 2.76 rads, P < 0.001). Two S2 transiliac-transsacral screws (1 C-arm and 1 O-arm) were categorized as unsafe based on scoring. There was no difference in screw accuracy between modalities.

CONCLUSIONS

A difference in accuracy between modalities could not be elucidated, whereas efficiency was improved with utilization of C-arm, with statistical significance. A statistically significant increase in radiation exposure to the surgeon using C-arm was found, which may be clinically significant over a career. The results of this study can be extrapolated to a fellow or surgeon early in practice. The decision between use of these modalities will vary depending on surgeon preference and hospital resources.

Tape suture for stabilization of incomplete posterior pelvic ring fractures-biomechanical analysis of a new minimally invasive treatment for incomplete lateral compression pelvic ring fractures

Background

Incomplete lateral compression fractures (including AO Type B2.1) are among the most common pelvic ring injuries. Although the treatment of choice remains controversial, sacroiliac (SI) screws are commonly used for the operative treatment of incomplete lateral compression fractures of the pelvic ring. However, the disadvantages of SI screws include the risk of nerve root or blood vessel injury. Recently, tape sutures have been found useful as stabilizing material for the treatment of injuries of the syndesmosis, the rotator cuff and knee ligaments. In this current study, we aimed to test the biomechanical feasibility of tape sutures to stabilize the pelvis in the setting of AO Type B2.1 injury.

Methods

Six human cadaveric pelvises underwent cyclic loading to compare the biomechanical stability of different osteosynthesis methods in a B2.1 fracture model. The methods tested in this experiment were a FiberTape® suture and the currently established SI screw. A 3D ultrasound tracking system was used to measure fracture fragment motion. Linear regression was used to model displacement and stiffness at the posterior and anterior pelvic ring.

Results

At the posterior fracture site, the FiberTape® demonstrated similar displacement (2.2 ± 0.8 mm) and stiffness (52.2 ± 18.0 N/mm) compared to the sacroiliac screw (displacement 2.1 ± 0.6 mm, P >  0.999; stiffness 50.8 ± 13.0 N/mm, P > 0.999).

Considering the anterior fracture site, the FiberTape® again demonstrated similar displacement (3.8 ± 1.3 mm) and stiffness (29.5 ± 9.0 N/mm) compared to the sacroiliac screw (displacement 2.9 ± 0.8 mm, P = 0.2196; stiffness 37.5 ± 11.5 N/mm, P = 0.0711).

Conclusion

The newly presented osteosynthesis, the FiberTape®, shows promising results for the stabilization of the posterior pelvic ring in AO Type B2.1 lateral compression fractures compared to a sacroiliac screw osteosynthesis based on its minimal-invasiveness and the statistically similar biomechanical properties.

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.

A novel computer navigation method for accurate percutaneous sacroiliac screw implantation: A technical note and literature review

The purpose of this study was to assess the accuracy of percutaneous sacroiliac screw (PSS) placement assisted by screw view model of navigation system for treatment of sacroiliac fractures.Data pertaining to 18 consecutive patients with posterior pelvic ring fracture who received sacroiliac screw fixation between January 2015 and July 2018 at the Second Hospital of Jilin University were retrospectively analyzed. Kirschner wires were placed under the guidance of navigation's screw view mode. The position of the screws was evaluated by computed tomography (CT) scan postoperatively. Fracture dislocation of sacroiliac joint was measured in axial, sagittal, and coronal views of 3 dimensional (3D) CT images preoperatively, postoperatively and at the last follow-up visit. The duration of trajectory planning, guide wire implantation time, screw placement time, intraoperative blood loss, and incidence of screw loosening and clinical complications were also assessed.A total of 27 screws were placed unilaterally or bilaterally into segments S1 or S2. Screw placement was rated as excellent for 88.9% of screws (n = 24), good for 7.4% (n = 2), and poor for 3.7% (n = 1). Preoperatively, the average fracture dislocation of sacroiliac joint on axial, sagittal, and coronal views was 14.3 mm, 9.6 mm, and 7.4 mm, respectively, and the corresponding postoperative figures were 5.6 mm, 3.2 mm, 4.1 mm, respectively. The corresponding correction rates were 60.8%, 66.7%, and 44.6%, respectively. The mean duration of trajectory planning was 6.5 min (2.7-8.9 min). Mean screw implantation time was 32 min (range, 20-53 min), and the mean guide wire implantation time was 3.7 min (range, 2.1-5.3 min). No clinical complications such as neurovascular injury, infection or screw loosening were observed on follow-up.The PSS placement under guidance of screw view model of navigation is a convenient, safe and reliable method.

Application of the Guiding Template Designed by Three-dimensional Printing Data for the Insertion of Sacroiliac Screws: a New Clinical Technique

This study is aimed to explore the clinical application of the guiding template designed by three-dimensional printing data for the insertion of sacroiliac screws. A retrospective study of 7 cases (from July 2016 to December 2016), in which the guiding template printed by the threedimensional printing technique was used for the insertion of sacroiliac screws of patients with posterior ring injuries of pelvis, was performed. Totally, 4 males and 3 females were included in template group, aged from 38 to 65 years old (mean 50.86±8.90). Of them, 5 had sacral fractures (3 with Denis type I and 2 with type II) and 2 the separation of sacroiliac joint. Guiding templates were firstly made by the three-dimensional printing technique based on the pre-operative CT data. Surgical operations for the stabilization of pelvic ring by applying the guiding templates were carried out. A group of 8 patients with sacroiliac injuries treated by percutaneous sacroiliac screws were analyzed as a control group retrospectively. The time of each screw insertion, volume of intra-operative blood loss, and the exposure to X ray were analyzed and the Matta's radiological criteria were used to evaluate the reduction quality. The Majeed score was used to evaluate postoperative living quality. The visual analogue scale (VAS) was applied at different time points to judge pain relief of coccydynia. All the 7 patients in the template group were closely followed up radiographically and clinically for 14 to 20 months, mean (16.57±2.44) months. Totally 9 sacroiliac screws for the S1 and S2 vertebra were inserted in the 7 patients. The time length for each screw insertion ranged from 450 to 870 s, mean (690.56±135.68) s, and the number of times of exposure to X ray were 4 to 8, mean (5.78±1.20). The intra-operative blood loss ranged from 45 to 120 mL, mean (75±23.32) mL. According to Matta's radiology criteria, the fracture and dislocation reduction were excellent in 6 cases and good in 1. The pre-operative VAS score ranged from 5.2 to 8.1, mean (7.13±1.00). The average one-week/six-month post-operative VAS was (5.33±0.78) and (1.33±0.66), respectively (P<0.05 when compared with pre-operative VAS). The 12-month postoperative Majeed score ranged from 86 to 92, mean (90.29±2.21). The three-dimensional printed guiding template for sacroiliac screw insertion, which could significantly shorten the operation time, provide a satisfied outcome of the stabilization of the pelvic ring, and protect doctors and patients from X-ray exposure, might be a practical and valuable new clinical technique.

Novel Thoracoscopic Navigation System With Augmented Real-Time Image Guidance for Chest Wall Tumors

BACKGROUND

We developed a thoracoscopic surgical navigation system with real-time augmented image guidance to assess the potential benefits for minimally invasive resection of chest wall tumors. The accuracy of localization of tumor and resection margin and the effect on task workload and confidence were evaluated in a chest wall tumor phantom.

METHODS

After scanning a realistic tumor phantom by cone-beam computed tomography and registering the data into the system, three-dimensional contoured tumor and resection margin was displayed. Fifteen surgeons were asked to localize the tumor margin and surgical margins with the thoracoscope alone. The same procedure was performed with the surgical navigation system activated, and results were compared between each attempt. A questionnaire and National Aeronautics and Space Administration Task Load Index were completed after.

RESULTS

The surgical navigation system significantly reduced localization error for the medial (p = 0.002) and superior tumor margin (p < 0.001), which was difficult to visualize by thoracoscopy alone. All surgical resection margins were improved circumferentially, including margins that were readily visible by thoracoscopy. National Aeronautics and Space Administration Task Load Index response scores showed a statistically significant reduction in workload in all subscales. There was a more than 50% mean reduction in workload for performance (10.1 vs 4.4, p = 0.001) and frustration (13.0 vs 5.4, p = 0.001).

CONCLUSIONS

This study showed that the thoracoscopic surgical navigation system providing augmented image guidance decreased tumor localization error for regions difficult to visualize thoracoscopically and also reduced surgical margin error circumferentially, regardless of thoracoscopic visibility. This system also reduced workload and increased surgeon's confidence in localizing challenging chest wall tumors.

Intraoperative CT and Surgical Navigation for Iliosacral Screws: Technique for Patients With Sacral Dysmorphism

Percutaneous iliosacral screw (IS) fixation for pelvic ring injuries with the use of an O-arm imaging system has been associated with decreased procedure time and improved accuracy of IS screw placement compared with the use of fluoroscopic guidance. Specifically, patients with sacral dysmorphism require identification of safe bony sacral corridors, using specific anatomical measurements, to decrease the likelihood of complications such as screw perforation. Intraoperative computed tomography imaging and navigation can aid in safe and accurate IS screw fixation in patients with difficult anatomy.

Accuracy of sacroiliac screw placement with and without intraoperative navigation and clinical application of the sacral dysmorphism score

INTRODUCTION

Percutaneously-placed sacroiliac (SI) screws are currently the gold-standard fixation technique for fixation of the posterior pelvic ring. The relatively high prevalence of sacral dysmorphism in the general population introduces a high risk of cortical breach with resultant neurovascular damage. This study was performed to compare the accuracy of SI screw placement with and without the use of intraoperative navigation, as well as to externally validate the sacral dysmorphism score in a trauma patient cohort.

PATIENTS AND METHODS

All trauma patients who underwent sacroiliac screw fixation for pelvic fractures at a level 1 trauma centre over a 6 year period were identified. True axial and coronal sacral reconstructions were obtained from their pre-operative CT scans and assessed qualitatively and quantitatively for sacral dysmorphism - a sacral dysmorphism score was calculated by two independent assessors. Post-operative CT scans were then analysed for breaches and correlated with the hospital medical records to check for any clinical sequelae.

RESULTS

68 screws were inserted in 36 patients, most sustaining injuries from road traffic accidents (50%) or falls from height (36.1%). There was a male preponderance (83.3%) with the majority of the screws inserted percutaneously (86.1%). Intraoperative navigation was used in 47.2% of the patient cohort. 30.6% of the cohort were found to have dysmorphic sacra. The mean sacral dysmorphism scores were not significantly different between navigated and non-navigated groups. Three cortical breaches occurred, two in patients with sacral dysmorphism scores >70 and occurring despite the use of intraoperative navigation. There was no significant difference in the rates of breach between navigated and non-navigated groups. None of the breaches resulted in any clinically observable neurovascular deficit.

CONCLUSION

The sacral dysmorphism score can be clinically applied to a cohort of trauma patients with pelvic fractures. In patients with highly dysmorphic sacra, reflected by high sacral dysmorphism scores, intraoperative navigation is not in itself sufficient to prevent cortical breaches. In such patients it would be prudent to consider instrumentation of the lower sacral corridors instead.

3D printing-based minimally invasive cannulated screw treatment of unstable pelvic fracture

Background

Open reduction and internal fixation of pelvic fractures could restore the stability of the pelvic ring, but there were several problems. Minimally invasive closed reduction cannulated screw treatment of pelvic fractures has lots advantages. However, how to insert the cannulated screw safely and effectively to achieve a reliable fixation were still hard for orthopedist. Our aim was to explore the significance of 3D printing technology as a new method for minimally invasive cannulated screw treatment of unstable pelvic fracture.

Methods

One hundred thirty-seven patients with unstable pelvic fractures from 2014 to 2016 were retrospectively analyzed. Based on the usage of 3D printing technology for preoperative simulation surgery, they were assigned to 3D printing group (n = 65) and control group (n = 72), respectively. These two groups were assessed in terms of operative time, intraoperative fluoroscopy, postoperative reduction effect, fracture healing time, and follow-up function. The effect of 3D printing technology was evaluated through minimally invasive cannulated screw treatment.

Results

There was no significant difference in these two groups with respect to general conditions, such as age, gender, fracture type, time from injury to operation, injury cause, and combined injury. Length of surgery and average number of fluoroscopies were statistically different for 3D printing group and the control group (p < 0.01), i.e., 58.6 vs. 72.3 min and 29.3 vs. 37 min, respectively. Using the Matta radiological scoring systems, the reduction was scored excellent in 21/65 cases (32.3%) and good in 30/65 cases (46.2%) for the 3D printing group, versus 22/72 cases (30.6%) scored as excellent and 36/72 cases (50%) as good for the control group. On the other hand, using the Majeed functional scoring criteria, there were 27/65 (41.5%) excellent and 26/65 (40%) good cases for the 3D printing group in comparison to 30/72 (41.7%) and 28/72 (38.9%) cases for the control group, respectively. This suggests no significant difference between these two groups about the function outcomes.

Conclusion

Full reduction and proper fixation of the pelvic ring and reconstruction of anatomical morphology are of great significance to patients’ early functional exercise and for the reduction of long-term complications. This retrospective study has demonstrated the 3D printing technology as a potential approach for improving the diagnosis and treatment of pelvic fractures.

Trial registration

The study was retrospectively registered at the Chinese Clinical Trial Registry, number: ChiCTR-TRC-17012798, trial registration date: 26 Sept. 2017.

Detection of articular perforations of the proximal humerus fracture using a mobile 3D image intensifier - a cadaver study

Background

The purpose of this study was to investigate the accuracy of perforation detection with multiplanar reconstructions using a mobile 3D image intensifier.

Methods

In 12 paired human humeri, K-wires perforating the subchondral bone and placed just below the cartilage level were directed toward five specific regions in the humeral head. Image acquisition was initiated by a fluoroscopy scan. Within a range of 90°, 45° external rotation (ER) and 45° internal rotation (IR). The number and percentage of detected perforating screws were grouped and analyzed. Furthermore, the fluoroscopic images were converted into multiplanar CT-like reconstructions. Each K-wire perforation was characterized as “detected” or “not detected”.

Results

In the series of fluoroscopy images in the standard neutral position at 30° internal rotation, and 30° external rotation, the perforations of all K-wires (n = 56) were detected. Twenty-nine (51.8%) of them were detected in one AP view, 22 (39.3%) in two AP views, and five (8.9%) in three AP views. All K-wire perforations (100%, n = 56) were detected in multiplanar reconstructions.

Conclusion

In order to reveal all of the intraoperative and postoperative screw perforations in a “five screw configuration”, conventional AP images should be established in both the neutral positions (0°), at 30° internal rotation and 30° external rotation. Alternatively, the intraoperative 3D scan with multiplanar reconstructions enables a 100% rate of detection of the screw perforations.

Development of a surgical navigation system based on 3D Slicer for intraoperative implant placement surgery

Implant placement has been widely used in various kinds of surgery. However, accurate intraoperative drilling performance is essential to avoid injury to adjacent structures. Although some commercially-available surgical navigation systems have been approved for clinical applications, these systems are expensive and the source code is not available to researchers. 3D Slicer is a free, open source software platform for the research community of computer-aided surgery. In this study, a loadable module based on Slicer has been developed and validated to support surgical navigation. This research module allows reliable calibration of the surgical drill, point-based registration and surface matching registration, so that the position and orientation of the surgical drill can be tracked and displayed on the computer screen in real time, aiming at reducing risks. In accuracy verification experiments, the mean target registration error (TRE) for point-based and surface-based registration were 0.31±0.06mm and 1.01±0.06mm respectively, which should meet clinical requirements. Both phantom and cadaver experiments demonstrated the feasibility of our surgical navigation software module.

Placement of iliosacral screws using 3D image-guided (O-Arm) technology and Stealth Navigation: comparison with traditional fluoroscopy

AIMS

We compared the accuracy, operating time and radiation exposure of the introduction of iliosacral screws using O-arm/Stealth Navigation and standard fluoroscopy.

MATERIALS AND METHODS

Iliosacral screws were introduced percutaneously into the first sacral body (S1) of ten human cadavers, four men and six women. The mean age was 77 years (58 to 85). Screws were introduced using a standard technique into the left side of S1 using C-Arm fluoroscopy and then into the right side using O-Arm/Stealth Navigation. The radiation was measured on the surgeon by dosimeters placed under a lead thyroid shield and apron, on a finger, a hat and on the cadavers.

RESULTS

There were no neuroforaminal breaches in either group. The set-up time for the O-Arm was significantly longer than for the C-Arm, while total time for placement of the screws was significantly shorter for the O-Arm than for the C-Arm (p = 0.001). The mean absorbed radiation dose during fluoroscopy was 1063 mRad (432.5 mRad to 4150 mRad). No radiation was detected on the surgeon during fluoroscopy, or when he left the room during the use of the O-Arm. The mean radiation detected on the cadavers was significantly higher in the O-Arm group (2710 mRem standard deviation (sd) 1922) than during fluoroscopy (11.9 mRem sd 14.8) (p < 0.01).

CONCLUSION

O-Arm/Stealth Navigation allows for faster percutaneous placement of iliosacral screws in a radiation-free environment for surgeons, albeit with the same accuracy and significantly more radiation exposure to cadavers, when compared with standard fluoroscopy.

TAKE HOME MESSAGE

Placement of iliosacral screws with O-Arm/Stealth Navigation can be performed safely and effectively. Cite this article: Bone Joint J 2016;98-B:696-702.

How to obtain and identify the acetabular anterior column axial view projection in patients?

PURPOSE

This study aims at sharing our experience as how to obtain and identify axial view image of the acetabular anterior column in patients.

METHODS

Pelvic computed tomography data of six normal adults were used to reconstruct three-dimensional (3D) models. The transparency of each 3D model was downgraded at the view perpendicular to the cross section of the anterior column axis to simulate the anterior column axial view image. Fluoroscopy was performed in all patients to obtain the anterior column axial view image in the operating room. Each fluoroscopic image was compared with the corresponding simulation image to analyze potential anatomic landmarks that were helpful to identify the translucent area (projection of the screw path) in the patients.

RESULTS AND CONCLUSIONS

To obtain ideal anterior column axial fluoroscopic image, the patient should be positioned supine with the leg of "abnormal side" straight and contralateral side flexion, abduction, and external rotation; the C-arm machine should be placed at the caudal end of the operation table with the C-arm fluoroscopic intensifier first positioned at the pelvic lateral view and then tilted approximately 30° toward the "abnormal side" and rotated approximately 45° toward the caudal end of the operation table. To identify the translucent area on the anterior column axial view fluoroscopic image obtained from the patient, the greater sciatic notch, the true pelvis edge, and the acetabulum should be identified first and the translucent area is located in the area surrounded by these three anatomic landmarks.

Improved accuracy of K-wire positioning into the glenoid vault by intraoperative 3D image intensifier-based navigation for the glenoid component in shoulder arthroplasty

INTRODUCTION

This article aimed to show that navigation, based on an intraoperative mobile 3D image intensifier, can improve the accuracy of central K-wire placement into the glenoid vault for glenoid component.

HYPOTHESIS

The navigated k-wire placement is more accurate and shows a smaller deviation angle to the standard centerline compared to the classical "free hand technic".

METHODS

In 34 fresh frozen sheep scapulae, 17 K-wire placements using the navigation (group 1) were compared with 17 using standard "face plane technique" (group 2). The relation to glenoid standard and alternative centerlines (CL) and the position within the glenoid vault were analyzed.

RESULTS

In groups 1 and 2 the angle between the K-wire and standard CL was 2.2° and 4.7°, respectively (P=0.01). The angle between the K-wire and alternative CL was 14.4° for group 1 and 17.2° for group 2 (P=0.02). More navigated K-wire positions were identified within a 5mm corridor along the glenoid vault CL (52 vs. 39; P=0.004).

DISCUSSION

Intraoperative 3D image intensifier-based navigation was more accurate and precise than standard K-wire placement.

TYPE OF STUDY AND LEVEL OF PROOF

Basic science study, evidence level III.

Image-guided installation of 3D-printed patient-specific implant and its application in pelvic tumor resection and reconstruction surgery

Nowadays, the diagnosis and treatment of pelvic sarcoma pose a major surgical challenge for reconstruction in orthopedics. With the development of manufacturing technology, the metal 3D-printed customized implants have brought revolution for the limb-salvage resection and reconstruction surgery. However, the tumor resection is not without risk and the precise implant placement is very difficult due to the anatomic intricacies of the pelvis. In this study, a surgical navigation system including the implant calibration algorithm has been developed, so that the surgical instruments and the 3D-printed customized implant can be tracked and rendered on the computer screen in real time, minimizing the risks and improving the precision of the surgery. Both the phantom experiment and the pilot clinical case study presented the feasibility of our computer-aided surgical navigation system. According to the accuracy evaluation experiment, the precision of customized implant installation can be improved three to five times (TRE: 0.75±0.18 mm) compared with the non-navigated implant installation after the guided osteotomy (TRE: 3.13±1.28 mm), which means it is sufficient to meet the clinical requirements of the pelvic reconstruction. However, more clinical trials will be conducted in the future work for the validation of the reliability and efficiency of our navigation system.

[Multiplanar reconstruction with mobile 3D image intensifier. Surgical treatment of proximal humerus fractures]

PURPOSE

The aim of this study was to analyze the applicability and advantages of the intraoperative use of a mobile 3D C-arm with multiplanar imaging for surgery of acute proximal humerus fractures.

MATERIALS AND METHODS

In this study 20 patients (11 female, 9 male, median age 70 years, range 35-91 years) with dislocated proximal humerus fractures (6 with 2 segments, 10 with 3 segments and 4 with 4 segments) were included. Preoperatively 3D scanning was performed and a reevaluation of the fracture in comparison to the plain radiographs was performed. After operative treatment another scan was performed to evaluate technical complications.

RESULTS

In comparison to the multiplanar reconstructions fracture morphology could not be correctly detected in 5 out of the 20 cases with plain radiographs. The preoperative image quality of the multiplanar reconstructions showed a significantly better assessment in comparison to the image quality with osteosynthesis (p < 0.05). The screws had to be replaced in 5 of the 20 patients.

CONCLUSION

Intraoperative 3D imaging with mobile image intensifier enables an accurate analysis of fracture morphology. Furthermore a quasi real time preoperative planning, evaluation of reduction and implant position with immediate operative relevance can be realized.

Iliosacral screw insertion using CT-3D-fluoroscopy matching navigation

BACKGROUND

Percutaneous iliosacral screw insertion requires substantial experience and detailed anatomical knowledge to find the proper entry point and trajectory even with the use of a navigation system. Our hypothesis was that three-dimensional (3D) fluoroscopic navigation combined with a preoperative computed tomography (CT)-based plan could enable surgeons to perform safe and reliable iliosacral screw insertion. The purpose of the current study is two-fold: (1) to demonstrate the navigation accuracy for sacral fractures and sacroiliac dislocations on widely displaced cadaveric pelves; and (2) to report the technical and clinical aspects of percutaneous iliosacral screw insertion using the CT-3D-fluoroscopy matching navigation system.

METHODS

We simulated three types of posterior pelvic ring disruptions with vertical displacements of 0, 1, 2 and 3cm using cadaveric pelvic rings. A total of six fiducial markers were fixed to the anterior surface of the sacrum. Target registration error over the sacrum was assessed with the fluoroscopic imaging centre on the second sacral vertebral body. Six patients with pelvic ring fractures underwent percutaneous iliosacral screw placement using the CT-3D-fluoroscopy matching navigation. Three pelvic ring fractures were classified as type B2 and three were classified as type C1 according to the AO-OTA classification. Iliosacral screws for the S1 and S2 vertebra were inserted.

RESULTS

The mean target registration error over the sacrum was 1.2mm (0.5-1.9mm) in the experimental study. Fracture type and amount of vertical displacement did not affect the target registration error. All 12 screws were positioned correctly in the clinical series. There were no postoperative complications including nerve palsy. The mean deviation between the planned and the inserted screw position was 2.5mm at the screw entry point, 1.8mm at the area around the nerve root tunnels and 2.2mm at the tip of the screw.

CONCLUSION

The CT-3D-fluoroscopy matching navigation system was accurate and robust regardless of pelvic ring fracture type and fragment displacement. Percutaneous iliosacral screw insertion with the navigation system is clinically feasible.

CT-3D-fluoroscopy matching navigation can reduce the malposition rate of iliosacral screw insertion for less-experienced surgeons

OBJECTIVES

The aim of the present study was to determine whether 3-dimensional (3D) fluoroscopic navigation combined with a preoperative computer tomography (CT)-based plan could enable surgeons to perform safe and reliable iliosacral screw insertion despite their limited experience.

METHODS

Eight pelvises with surrounding soft tissue donated from embalmed cadavers were used. Kirschner wires with a diameter of 3 mm were placed across the ilia bilaterally into the S1 and S2 vertebrae by 4 orthopaedic trainees. In 4 specimens, wires were placed across the right ilium using conventional technique and the left ilium using the CT-3D-fluoroscopy matching navigation system. In 4 other specimens, wires were placed across the right ilium using the 3D-fluoroscopic navigation system and the left ilium using the CT-3D-fluoroscopy matching navigation system. A postoperative CT-based analysis of wire localization was performed. The number of wire insertions until the final position check, operation duration, and radiation time and dose were also evaluated.

RESULTS

The percentage of wires inserted correctly was higher in the CT-3D-fluoroscopy matching navigated group (100%) than in the conventional technique group (50%) and 3D-fluoroscopic navigation group (50%). The number of wire insertions and radiation time were significantly lower with both navigation systems than with the conventional technique, whereas there was no significant difference between the navigation systems. There were no significant differences in operation time and radiation dose among the 3 groups.

CONCLUSIONS

The CT-3D-fluoroscopy matching navigation system reduced the malposition rate of percutaneous iliosacral screw insertion when performed by less experienced surgeons.

Current state of computer-assisted trauma surgery

Computer assisted surgery (CAS) was first used in neurosurgery. Currently, CAS has gained popularity in several surgical disciplines including urology and abdominal surgery. In trauma and orthopaedic surgery, computer assisted systems are used for fracture reduction, planning and positioning of implants as well as the accurate implantation of hip and knee prostheses. The patient's anatomy is virtualized and the surgical instruments integrated into the digitized image background, thus allowing the surgeon to navigate the surgical instruments and the bone in an improved, virtual visual environment. CAS improves overall accuracy, reducing intraoperative radiation exposure and minimizing unnecessary surgical dissection combined with increased patient and surgeon safety. However, limitations include prolonged surgical time, technical errors and cost implications. This article will outline the current state of computer assisted trauma surgery including its implications and specific challenges in orthopaedic trauma surgery.