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

Operative management of sacroiliac joint dislocation in children with unstable pelvic fractures - A STROBE-compliant investigation

Objective

Injuries involving severe spinal axial loading may be accompanied by sacroiliac joint dislocations. In children, these injuries are relatively rare, and there is little information on their optimal management in young patients. We conducted a multicentre study to investigate the outcome of surgical treatment of unstable pelvic fracture with sacroiliac joint dislocation in children.

Patients & methods

We assessed the quality of surgical reduction and functional outcome at follow-up in 7 patients (5 girls, 2 boys) with a median age of 6.4 years (range: 4.2-14.8 years). Patients with pelvic fractures and sacroiliac joint dislocations were treated at four international paediatric level 1 trauma centres between January 2008 and August 2023. We applied the Matta criteria to assess the quality of fracture reduction and graded the functional follow-up results using adjusted Majeed score.

Results

At follow-up, 3 patients showed excellent fracture reduction, with 2 patients showing good reduction and 2 patients exhibiting fair fracture reduction according to the Matta criteria. At follow-up visits at a median of 12 months (range: 3-84 months) after the injury, patients achieved a median adjusted Majeed score of 76 (range: 63 to 76).

Conclusions

Unstable pelvic injuries with sacroiliac joint dislocation without comminution can be stabilised with a single iliosacral screw in children. Comminuted pelvic fractures with unstable sacroiliac dislocation require stabilisation with lateral compression screws or plates. In case of residual pelvic instability after internal fixation, an additional external fixator or pelvic hammock should be applied to optimize the stability of fixation.

Incidence of Suboptimal Fluoroscopic Outlet Imaging of the Sacrum and Pelvic Retroversion Necessary for Optimal Views

OBJECTIVES

To estimate the prevalence of suboptimal fluoroscopy of sacral outlet images due to anatomic and equipment dimensions. Pelvic retroversion is hypothesized to mitigate this issue.

METHODS

DESIGN

In silico simulations using retrospectively collected computed tomography (CT) data from human patients.

SETTING

Level I trauma center.

PATIENT SELECTION CRITERIA

Adults with OTA/AO 61 pelvic ring disruptions treated with posterior pelvic fixation between July and December 2021.

OUTCOME MEASURES AND COMPARISONS

C-arm tilt angles required to obtain 3 optimal fluoroscopic sacral outlet images, defined as vectors from pubic symphysis to S2 and parallel to the first and second sacral neural foramina, were calculated from sagittal CT images. A suboptimal view was defined as collision of the C-arm radiation source or image intensifier with the patient/operating table at the required tilt angle simulated using the dimensions of 5 commercial C-arm models and trigonometric calculations. Incidence of suboptimal outlet views and pelvic retroversion necessary to obtain optimal views without collision, which may be obtained by placement of a sacral bump, was determined for each view for all patients and C-arm models.

RESULTS

CT data from 72 adults were used. Collision between patient and C-arm would occur at the optimal tilt angle for 17% of simulations and at least 1 view in 68% of patients. Greater body mass index was associated with greater odds of suboptimal imaging (standard outlet: odds ratio [OR] 0.84, confidence interval [CI] 0.79-0.89, P < 0.001; S1: OR 0.91, CI 0.87-0.97, P = 0.002; S2: OR 0.85, CI 0.80-0.91, P < 0.001). S1 anterior sacral slope was associated with suboptimal S1 outlet views (OR 1.12, Cl 1.07-1.17, P < 0.001). S2 anterior sacral slope was associated with suboptimal standard outlet (OR 1.07, Cl 1.02-1.13, P = 0.004) and S2 outlet (OR 1.16, Cl 1.09-1.23, P < 0.001) views. Retroversion of the pelvis 15-20 degrees made optimal outlet views possible without collision in 95%-99% of all simulations, respectively.

CONCLUSIONS

Suboptimal outlet imaging of the sacrum is associated with greater body mass index and sacral slope at S1 and S2. Retroversion of the pelvis by 15-20 degrees with a bump under the distal sacrum may offer a low-tech solution to ensure optimal fluoroscopic imaging for percutaneous fixation of the posterior pelvic ring.

LEVEL OF EVIDENCE

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

[Translated article] Insertion of S1 iliosacral screws in the computed tomography room: An alternative to improve safety in the percutaneous management of posterior pelvic ring injuries

INTRODUCTION

The main complication of percutaneous iliosacral screw fixation is implant malposition, which can lead to vascular and nerve damage. The anatomical variability of the sacrum can make screw insertion difficult under fluoroscopic guidance. Among the methods described to improve the accuracy of this technique, stands out the use of computed tomography (CT). The aim of this study is to compare the results of iliosacral screw insertion with fluoroscopy or CT navigation.

METHODOLOGY

Retrospective cohort study of 66 iliosacral screws in 56 patients during 11 years. The screws were inserted with fluoroscopy in the operating room or with CT in the radiodiagnosis area. We collected data on patient characteristics, lesions, treatment, and clinical and radiological results.

RESULTS

Forty-seven screws were inserted with fluoroscopy and 19 with CT. A percentage of 18.2 of screws perforated the S1 osseous corridor. All of them were inserted with fluoroscopy guidance (0 vs. 34%; p<0.01). Those operated with CT accumulated more sacral dysmorphism criteria than those operated with fluoroscopy (2.2 vs. 1.6; p=0.02). The S1 corridor on the axial CT view was narrower in those in whom perforation had occurred (18.8 vs. 21.0mm; p=0.02). Two cases with perforation developed S1 radiculalgia. Two endopelvic screws had to be removed.

CONCLUSION

We advise the use of CT guidance for iliosacral screw insertion in patients with sacral dysmorphism or narrow S1 corridors in facilities where other navigation methods are not available.

Insertion of S1 iliosacral screws in the computed tomography room: An alternative to improve safety in the percutaneous management of posterior pelvic ring injuries

INTRODUCTION

The main complication of percutaneous iliosacral screw fixation is implant malposition, which can lead to vascular and nerve damage. The anatomical variability of the sacrum can make screw insertion difficult under fluoroscopic guidance. Among the methods described to improve the accuracy of this technique, stands out the use of computed tomography (CT). The aim of this study is to compare the results of iliosacral screw insertion with fluoroscopy or CT navigation.

METHODOLOGY

Retrospective cohort study of 66 iliosacral screws in 56 patients during 11 years. The screws were inserted with fluoroscopy in the operating room or with CT in the radiodiagnosis area. We collected data on patient characteristics, lesions, treatment, and clinical and radiological results.

RESULTS

Forty-seven screws were inserted with fluoroscopy and 19 with CT. A percentage of 18.2 of screws perforated the S1 osseous corridor. All of them were inserted with fluoroscopy guidance (0 vs. 34%; p<0.01). Those operated with CT accumulated more sacral dysmorphism criteria than those operated with fluoroscopy (2.2 vs. 1.6; p=0.02). The S1 corridor on the axial CT view was narrower in those in whom perforation had occurred (18.8 vs. 21.0mm; p=0.02). Two cases with perforation developed S1 radiculalgia. Two endopelvic screws had to be removed.

CONCLUSION

We advise the use of CT guidance for iliosacral screw insertion in patients with sacral dysmorphism or narrow S1 corridors in facilities where other navigation methods are not available.

Topographic localization of the sacroiliac joint and superior gluteal artery branches on the posterolateral ilium

Latrogenic vascular injuries at the posterior ilium during sacroiliac screw placements are not uncommon. Though intra-operative imaging reduces the risk of such injuries, anatomical localization of the sacral segments using discrete topographical landmarks is not currently available. This descriptive study proposes the use of an anatomical grid system to localize the sacroiliac articulation on the posterolateral ilium. It also investigates the positional variability of the branches of the superior gluteal artery (SGA) within areas defined by the grid. 48 dried adult hip bones were examined to determine the position of the sacral articular surface on the posterolateral surface of the ilium. A novel grid-system was defined and used to map the positions of the articulation of the first two sacral segments on the posterolateral ilium. Superficial and deep branches of the SGA were dissected in donor cadavers and their courses were virtually overlayed on the grid system. The grid system localized the sacral articular surfaces within a defined area on the posterior ilium. Arterial distributions indicated the presence of the superficial branch of SGA more frequently over the screw insertion area (at an intermuscular plane), while the deep branch ran closer to the ilium but antero-inferior to the screw placement areas. This study proposes a new topographical perspective of visualizing SGA branches with respect to the cranial sacral segments. Precise localization of vascular anatomy may help to reduce potential risk of injury during sacroiliac screw placements.

Computer-assisted Navigation in Lumbar Spine Instrumented Fusions: Comparison of In-hospital and 30-Day Postoperative Complications With Nonnavigated Fusions in a National Database

OBJECTIVE

To compare in-hospital and 30-day postoperative complications for lumbar spine operations with and without use of computer-assisted navigation.

METHODS

Patients who underwent 1-level to 3-level lumbar spinal instrumentation and fusions 2011 to 2014 were identified in the American College of Surgeons National Surgical Quality Improvement Program database. Emergent procedures and patients aged younger than 18 years were excluded. Patients whose surgery involved the use of computer-assisted navigation were propensity score matched 1:4 based on preoperative demographics and comorbidities to operations without the use of navigation. Multivariate analysis was done to compare postoperative complications.

RESULTS

In total, 8,500 patients (average age: 60.7 ± 12.9, male 3,866, female 4,634) were analyzed (1,700 navigation, 6,800 Non-Navigated). Operations with navigation had significantly fewer overall complications (24% vs. 27%, P = 0.008; odds ratio [OR] = 0.83; CI = 0.73 to 0.95), fewer minor complications (20% vs. 24%, P = 0.002; OR = 0.80; CI = 0.70 to 0.91), fewer blood transfusions (17% v. 20%, P = 0.013; OR = 0.82; CI = 0.71 to 0.95), more wound dehiscences (0.4% vs. 0.8%, P = 0.022; OR = 2.16; CI = 1.12,4.19), and shorter average lengths of hospital stays (4.8 ± 4.8 vs. 5.1 ± 5.8 days, P = 0.01). Operations with computer navigation had significantly longer average surgical times (247 ± 129 vs 221 ± 115 minutes, P < 0.001). No significant differences were observed in 30-day revision rates, readmissions, and mortality.

CONCLUSION

Although use of computer-assisted navigation in short-segment lumbar spine fusions (1 to 3 levels) did not decrease revision rates for screw misplacement within 30 days postoperatively, it independently reduced the frequency of blood transfusions and minor complications and decreased hospital lengths of stay compared with operations without navigation. These benefits came at the expense of increased surgical times and wound dehiscences within 30 days postoperatively. Given the inherent limitations of large national databases, these results warrant confirmation through prospective, multicenter investigations.

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.

Sacroiliac screws fixation navigated with three-dimensional printing personalized guide template for the treatment of posterior pelvic ring injury: A case report

Objective

Pelvic injuries refer to the disruption of the inherent structural and mechanical integrity of the pelvic ring. Sacroiliac screw fixation technique is often used for the treatment of posterior pelvic ring injury, which is prone to the iatrogenic injury. Various attempts were proposed to avoid iatrogenic injuries, while the executing processes are usually too cumbersome. The patient-personalized guide template based on 3D printing technology has been considered as a promising method, which can achieve lower deviation and higher accuracy in a simple and convenient way. We reported the first case of posterior pelvic ring injury using 3D printing personalized guide template with the verification of intraoperative CT.

Methods

The subject was a 74-year-old female with posterior pelvic ring injury. Two patient-specific guide templates were customized based on 3D printing technology, one for S1 and the other for S2. We used the guide templates for navigation to place the sacroiliac screws. The placement of screws was verified by intraoperative CT. Intraoperative and postoperative variables were collected.

Results

The technique helped us successfully insert the sacroiliac screws into the safe zone. The intraoperative blood loss was 23.03 ml, and the duration of operation was 62 min. The exposure dose during CT scanning was 7.025 mSv. The assessment of screws position was excellent. Furthermore, there was no sign of any functional impairment postoperatively.

Conclusion

Sacroiliac screws fixation with the assistance of 3D printing personalized guide template under the verification of intraoperative CT may be a promising method to treat posterior pelvic ring injuries.

Fluoroscopy-guided vs. navigated iliosacral screw placement with intraoperative 3D scan or postoperative CT control: Impact of the clinical workflow on patients' radiation exposure: Radiation exposure of different workflows for iliosacral screw placement

INTRODUCTION

To guide iliosacral screws (ISS) and verify safe placement different techniques, e.g. Fluoroscopy-guided (FSG) or 3D navigation are known. However, higher radiation exposure for the conventional technique is a concern. It was the aim of this experimental study to evaluate radiation exposure for three clinical workflows.

METHODS

An anthropomorphic, cross sectional dosimetry phantom was equipped with metal oxide semiconductor field effect transistors to measure organ specific radiation exposure. The effective dose was calculated. Radiation exposure was measured for FSG placement of 2 transverse ISS based on clinical experience regarding fluoroscopy time (240s). Additional measurements were conducted to calculate the effective dose for an intraoperative 3D scan as used for navigated ISS (high-quality 3D), for intraoperative verification of proper guide wire placement (standard-quality 3D) and for postoperative CT, using three different protocols. The following workflows were compared: FSG including postoperative CT (FSG-CT, including 3 different protocols) vs. FSG with intraoperative 3D scan in standard quality (FSG-3D) vs. navigation including two intraoperative 3D scan for navigated ISS (NAV-3D).

RESULTS

The effective dose for FSG-CT ranged from 4.41 mSv to 5.27 mSv. FSG-3D resulted in a total of 4.93 mSv. For NAV-3D, the effective dose was the lowest (3.00 mSv). The effective dose of a high-quality 3D scan required for navigation was 1.94 mSv, compared to 1.06 mSv for a standard-quality 3D scan as used for control.

CONCLUSIONS

Intraoperative 3D scanning may be recommended, either combined with prior FSG ISS placement or following 3D navigation without increasing radiation exposure compared with alternative workflows with postoperative CT control.

Navigated Percutaneous Sacroiliac Screw Fixation in Unstable Pelvic Ring Fracture

Since the late 1990s, navigation systems have been widely used in a variety of orthopaedic surgical procedures, with the majority of these procedures being complex arthroplasty surgeries and the correction of spinal abnormalities. Navigation systems are, however, infrequently used in trauma cases, especially in unstable pelvic ring fractures. The conventional method of percutaneous sacroiliac screw fixation typically used fluoroscopic image intensifiers to fix unstable pelvic ring fractures. We will examine how navigation systems can be used in trauma situations, particularly those involving unstable posterior pelvic ring fractures and focus on the advantages and disadvantages that we experienced during management.

Differences in Accuracy and Radiation Dose in Placement of Iliosacral Screws: Comparison between 3D and 2D Fluoroscopy

Percutaneous iliosacral screw fixation is a widely accepted method of stabilizing the posterior pelvic ring. Recently developed tools such as 3D-navigated fluoroscopy and computed navigation seem to prevent a surgeon from conducting screw misplacement. The study aimed to comparatively assess the introduction of sacroiliac screw placement using 2D and 3D fluoroscopy in terms of accuracy and radiation exposure. Iliosacral screws were introduced in 37 patients using 2D (group N1) and in 36 patients using 3D fluoroscopy (group N2) techniques. Overall, 61 and 56 screws were introduced in groups N1 and N2, respectively. Screw placement accuracy was assessed using postoperative computed tomography and Smith’s scale. Intraoperative radiation exposure was also assessed. No differences were noted between groups in terms of screw positioning accuracy and radiation dose. Both 2D and 3D fluoroscopy provide good visualization for safely placing percutaneous iliosacral joint screws. Using 3D fluoroscopy-based navigation in comparison with 2D fluoroscopy is not advantageous.

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.].

Computer-Assisted Surgical Navigation for Primary and Metastatic Bone Malignancy of the Pelvis: Current Evidence and Future Directions

Computer-assisted navigation and robotic surgery have gained popularity in the treatment of pelvic bone malignancies, given the complexity of the bony pelvis, the proximity of numerous vital structures, and the historical challenges of pelvic bone tumor surgery. Initial interest was on enhancing the accuracy in sarcoma resection by improving the quality of surgical margins and decreasing the incidence of local recurrences. Several studies have shown an association between intraoperative navigation and increased incidence of negative margin bone resection, but long-term outcomes of navigation in pelvic bone tumor resection have yet to be established. Historically, mechanical stabilization of pelvic bone metastases has been limited to Harrington-type total hip arthroplasty for disabling periacetabular disease, but more recently, computer-assisted surgery has been employed for minimally invasive percutaneous fixation and stabilization; although still in its incipient stages, this procedure is potentially appealing for treating patients with bone metastases to the pelvis. The authors review the literature on navigation for the treatment of primary and metastatic tumors of the pelvic bone and discuss the best practices and limitations of these techniques.

Is there a difference between navigated and non-navigated robot cohorts in robot-assisted spine surgery? A multicenter, propensity-matched analysis of 2,800 screws and 372 patients

BACKGROUND CONTEXT

Robot-assisted spine surgery continues to rapidly develop as evidenced by the growing literature in recent years. In addition to demonstrating excellent pedicle screw accuracy, early studies have explored the impact of robot-assisted spine surgery on reducing radiation time, length of hospital stay, operative time, and perioperative complications in comparison to conventional freehand technique. Recently, the Mazor X Stealth Edition was introduced in 2018. This robotic system integrates Medtronic's Stealth navigation technology into the Mazor X platform, which was introduced in 2016. It is unclear what the impact of these advancements have made on clinical outcomes.

PURPOSE

To compare the outcomes and complications between the most recent iterations of the Mazor Robot systems: Mazor X and Mazor X Stealth Edition.

STUDY DESIGN

Multicenter cohort PATIENT SAMPLE: Among four different institutions, we included adult (≥18 years old) patients who underwent robot-assisted spine surgery with either the Mazor X (non-navigated robot) or Stealth (navigated robot) platforms.

OUTCOME MEASURES

Primary outcomes included robot time per screw, fluoroscopic radiation time, screw accuracy, robot abandonment, and clinical outcomes with a minimum 90 day follow up.

METHODS

A one-to-one propensity-score matching algorithm based on perioperative factors (e.g. demographics, comorbidities, primary diagnosis, open vs. percutaneous instrumentation, prior spine surgery, instrumented levels, pelvic fixation, interbody fusion, number of planned robot screws) was employed to control for the potential selection bias between the two robotic systems. Chi-square/fisher exact test and t-test/ANOVA were used for categorical and continuous variables, respectively.

RESULTS

From a total of 646 patients, a total of 372 adult patients were included in this study (X: 186, Stealth: 186) after propensity score matching. The mean number of instrumented levels was 4.3. The mean number of planned robot screws was 7.8. Similar total operative time and robot time per screw occurred between cohorts (p>0.05). However, Stealth achieved significantly shorter fluoroscopic radiation time per screw (Stealth: 7.2 seconds vs. X: 10.4 seconds, p<.001) than X. The screw accuracy for both robots was excellent (Stealth: 99.6% vs. X: 99.1%, p=0.120). In addition, Stealth achieved a significantly lower robot abandonment rate (Stealth: 0% vs. X: 2.2%, p=0.044). Furthermore, a lower blood transfusion rate was observed for Stealth than X (Stealth: 4.3% vs. X: 10.8%, p=0.018). Non-robot related complications such as dura tear, motor/sensory deficits, return to the operating room during same admission, and length of stay was similar between robots (p>0.05). The 90-day complication rates were low and similar between robot cohorts (Stealth: 5.4% vs. X: 3.8%, p=0.456).

CONCLUSION

In this multicenter study, both robot systems achieved excellent screw accuracy and low robot time per screw. However, using Stealth led to significantly less fluoroscopic radiation time, lower robot abandonment rates, and reduced blood transfusion rates than Mazor X. Other factors including length of stay, and 90-day complications were similar.

Open reduction and navigated Iliosacral screws for vertically unstable pelvic fractures

AIMS

To evaluate clinical and radiological results of vertically unstable pelvic fractures managed by open reduction and navigated iliosacral screws.

PATIENTS AND METHODS

The study included eleven patients with complex posterior ring fractures with vertical instability admitted to our hospital and managed with CT navigated iliosacral screws. There were 7 type C1, 2 C2 and 2 C3, according to Tile classification. Three patients presented a spino-pelvic dissociation and four a vertical sacral fracture affecting the foramina (Denis 2). Vertical displacement, pelvic deformity and asymmetry were measured. Tornetta and Matta criteria were used to assess the quality of pelvic reduction.

RESULTS

An excellent reduction was achieved in 9 fractures and a good reduction in two. Asymmetry index improved from 13.18 to 2.72. Deformity index improved from 0.049 to 0.010. Only two patients with a Denis 2 fracture showed secondary displacement during follow-up. Four patients presented neurological complications due to their initial injuries. Seven patients were able to resume their previous activities.

CONCLUSION

CT navigated IS screws provide enough stability after an anatomic reduction of the fracture. There was no complication related to screw insertion and adequate screw positioning was achieved in all the cases.

Multidimensional Pelvic Fluoroscopy: A New and Novel Technique for Assessing Safety and Accuracy of Percutaneous Iliosacral Screw Fixation

OBJECTIVES

Multidimensional fluoroscopy is new imaging technology that generates intraoperative cross sectional imaging. Can this technology be used to assess accuracy and safety of percutaneously placed iliosacral screws intraoperatively?

DESIGN

Retrospective study.

SETTING

Level 1 academic trauma center.

PATIENTS/PARTICIPANTS

Fifty-two consecutive patients during a 7-month period with unstable posterior pelvic ring disruptions.

INTERVENTION

All patients were treated with percutaneous iliosacral and/or transsacral screw fixation by a single experienced surgeon. Traditional triplanar fluoroscopy was performed during guidepin insertion. Intraoperative multidimensional fluoroscopy was used for all patients after iliosacral screw fixation.

MAIN OUTCOME MEASUREMENTS

Intraoperative multidimensional fluoroscopy and postoperative computed tomography (CT) scans for each patient were retrospectively reviewed by the treating surgeon and another trauma surgeon. Screw position in relation to the sacral neuroforamen was assessed using multidimensional fluoroscopy and compared to postoperative CT scan. Screws were classified as extraforaminal, juxtaforaminal, or intraforaminal.

RESULTS

No screws were intraforaminally seen on intraoperative multidimensional fluoroscopy or postoperative CT scan. All iliosacral and transsacral screws were considered safe. Intraobserver and interobserver variability existed between reviewers when grading screws as extraforaminal versus juxtaforaminal. This was not clinically significant because both agreed that extraforaminal and juxtaforaminal screw positions are safe. Multidimensional fluoroscopy was used in 3 patients to assess guidepin placement before definitive screw fixation. Two patients underwent a change of fixation after reviewing multidimensional fluoroscopy. No postoperative neurological examination changes occurred.

CONCLUSIONS

Multidimensional fluoroscopy is a novel imaging technology that can safely be used intraoperatively to accurately determine iliosacral and transsacral screw placement.

LEVELS OF EVIDENCE

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

Plate versus sacroiliac screw fixation for treating posterior pelvic ring fracture: a Systematic review and meta-analysis

BACKGROUND

Whether plate fixation or sacroiliac (SI) screw fixation is the better treatment for posterior pelvic ring disruption is controversial. The aim of this systematic review and meta-analysis was to compare the two fixation methods.

MATERIAL AND METHODS

The MEDLINE, Embase, and Cochrane Library databases were systematically searched for studies comparing plate and SI screw fixations in posterior pelvic ring injuries. Intraoperative variables, postoperative complications, and clinical/radiological scores were compared between the techniques.

RESULTS

Eleven studies were included in the qualitative synthesis, and nine in the meta-analysis. The meta-analysis included 202 patients who underwent plate fixation and 258 patients who underwent SI screw fixation. The incision length and mean blood loss were greater in the plate group than in the SI screw group (standard mean difference (SMD) = 7.29, 95% confidence interval (CI): 3.18-11.40; SMD = 5.09, 95% CI: 2.08-8.09, respectively). Patients in the SI screw group had more X-ray exposure than those in the plate group (SMD = -5.96, 95% CI: -7.95-3.97). There were no differences in operation time and intraoperative complications (SMD = -1.42, 95% CI: -3.90-1.05; OR = 0.92, 95% CI: 0.05-18.60, respectively). The duration of hospital stay was longer in the plate group (SMD = 2.21, 95% CI: 1.74-2.68). There were no differences in postoperative neurological complications, infection rate, and nonunion rate (OR = 1.62, 95% CI: 0.20-13.21; OR = 2.10, 95% CI: 0.74-5.94; OR = 1.12, 95% CI: 0.26-4.87, respectively), but implant loosening was more common in the SI screw group (OR = 0.18, 95% CI: 0.04-0.87). There was no difference in revision surgery (OR = 0.23, 95% CI: 0.02-2.14). The total excellent rating according to the postoperative Majeed functional and Matta scores was higher in the SI screw group (OR = 0.43, 95% CI: 0.20-0.91; OR = 0.24, 95% CI: 0.08-0.74, respectively).

CONCLUSIONS

SI screw fixation was superior to plate fixation in the functional and radiological scores, but implant loosening was more common for the treatment posterior pelvic ring injuries.

Vertical Shear Pelvic Ring Injury Adjacent to Retained Pelvic Hardware: A Case Report

CASE

A 47-year-old obese woman presented with a vertical shear (VS) pelvic ring injury after a motor vehicle accident around her previous posterior pelvic hardware. The patient underwent closed reduction with percutaneous posterior screw fixation using combined fluoroscopy and O-arm (Medtronic).

CONCLUSION

A rare case of VS pelvic injury with indwelling posterior pelvic hardware does not automatically preclude placement of percutaneous sacroiliac and transiliac-transsacral screws. Combining fluoroscopic imaging and O-arm enables safe screw placement, saving patients from invasive surgeries.

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.

Safety and efficacy of 2D-fluoroscopy-based iliosacral screw osteosynthesis: results of a retrospective monocentric study

Introduction

Iliosacral screw osteosynthesis is a well-accepted procedure for stabilization of sacral fractures and iliosacral (fracture) dislocations.

Materials and Methods

In this monocentric study, safety and efficacy of conventional 2D-fluoroscopic-guided iliosacral screw insertion were evaluated.

Results

During a 10-year period (2005–2014), 98 patients between the age of 18 and 65 years received 207 iliosacral screws in 101 procedures. Average patient age was 43.2 years. There were 46 Type B and 40 Type C injuries in the AO/OTA classification, nine patients had a fragility fracture of the pelvis. In three patients, primary radiological data were missing. The indication for surgical treatment was a sacral fracture in 97 patients, a pure iliosacral dislocation in 37 patients and a fracture-dislocation in 31 patients. 70 procedures were performed with the patient in supine position, 31 with the patient in prone position. Surgery was done in a minimal-invasive technique in 76 patients, in 22 patients an open reduction was necessary before screw insertion. 81 patients received a unilateral, 17 patients a bilateral screw osteosynthesis. 199 screws were inserted in S1, only eight screws in S2. 65 patients received two screws unilaterally, ten patients two screws bilaterally. There were no vascular or neurologic complications. During in-hospital stay, there were seven complications, which needed 12 operative revisions: three wound infections, two hematomas, one screw malalignment and one early screw loosening. In 28 patients with 56 iliosacral screws, a pelvic CT-scan was performed during follow-up. A penetration of a cortical layer was diagnosed in 20 of these screws. All penetrations were seen in double screw osteosynthesis of S1. In none of the patients, complaints could be explained by the malalignment of these screws. Five operative revisions were performed during follow-up: two for screw loosening, two for fracture healing problems and one for screw malalignment. Metal removal was performed in 39 patients with 75 screws. 2D-fluoroscopic-guided iliosacral screw osteosynthesis is a safe and efficient procedure in clinical practice.

Discussion

A thorough preoperative evaluation of the morphology of the upper sacrum and careful operative procedure are indispensable. Fluoroscopic views in AP, lateral, inlet and outlet must allow recognition of all anatomical landmarks. The indication for double screw osteosynthesis in S1 should be taken with caution. Screw malalignments do not inevitably correlate with complaints.

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.

Interactive Flying Frustums (IFFs): spatially aware surgical data visualization

PURPOSE

As the trend toward minimally invasive and percutaneous interventions continues, the importance of appropriate surgical data visualization becomes more evident. Ineffective interventional data display techniques that yield poor ergonomics that hinder hand-eye coordination, and therefore promote frustration which can compromise on-task performance up to adverse outcome. A very common example of ineffective visualization is monitors attached to the base of mobile C-arm X-ray systems.

METHODS

We present a spatially and imaging geometry-aware paradigm for visualization of fluoroscopic images using Interactive Flying Frustums (IFFs) in a mixed reality environment. We exploit the fact that the C-arm imaging geometry can be modeled as a pinhole camera giving rise to an 11-degree-of-freedom view frustum on which the X-ray image can be translated while remaining valid. Visualizing IFFs to the surgeon in an augmented reality environment intuitively unites the virtual 2D X-ray image plane and the real 3D patient anatomy. To achieve this visualization, the surgeon and C-arm are tracked relative to the same coordinate frame using image-based localization and mapping, with the augmented reality environment being delivered to the surgeon via a state-of-the-art optical see-through head-mounted display.

RESULTS

The root-mean-squared error of C-arm source tracking after hand-eye calibration was determined as [Formula: see text] and [Formula: see text] in rotation and translation, respectively. Finally, we demonstrated the application of spatially aware data visualization for internal fixation of pelvic fractures and percutaneous vertebroplasty.

CONCLUSION

Our spatially aware approach to transmission image visualization effectively unites patient anatomy with X-ray images by enabling spatial image manipulation that abides image formation. Our proof-of-principle findings indicate potential applications for surgical tasks that mostly rely on orientational information such as placing the acetabular component in total hip arthroplasty, making us confident that the proposed augmented reality concept can pave the way for improving surgical performance and visuo-motor coordination in fluoroscopy-guided surgery.

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

Background

Iliosacral screw fixation is a popular method for the management of posterior pelvic ring fractures or dislocations, providing adequate biomechanical stability. Our aim in this study was to describe the use of a new patient-specific external template to guide the insertion of iliosacral screws and to evaluate the efficacy and safety of this technique compared with the conventional fluoroscopy-guided technique.

Methods

This was a retrospective study of patients with incomplete or complete posterior pelvic ring disruptions who required iliosacral screw fixation. For analysis, patients were divided into two groups: the external template group (37 screws in 22 patients) and the conventional group (28 screws in 18 patients). The operative time per screw, radiation exposure time and the rate of screw perforation (accuracy) were compared between groups. In the external template group, the difference between the actual and planned iliosacral screw position was also compared.

Results

In the conventional group, the average operative time per screw was 39.7 ± 10.6 min, with an average radiation exposure dose of 1904.0 ± 844.5 cGy/cm², with 4 cases of screw perforation. In the external template group, the average operative time per screw was 17.9 ± 4.7 min, with an average radiation exposure dose of 742.8 ± 230.6 cGy/cm² and 1 case of screw perforation. In the template group, the mean deviation distance between the actual and planned screw position was 2.75 ± 1.0 mm at the tip, 1.83 ± 0.67 mm in the nerve root tunnel zone and 1.52 ± 0.48 mm at the entry point, with a mean deviation angle of 1.73 ± 0.80°.

Conclusions

The external template provides an accurate and safe navigation tool for percutaneous iliosacral screw insertion that could decrease the operative time and radiation exposure.

Posterior pelvic ring fractures: Intraoperative 3D-CT guided navigation for accurate positioning of sacro-iliac screws

INTRODUCTION

Posterior pelvic ring fractures frequently pose a problem of stability with an elevated risk of complications. The traditional method of percutaneous sacroiliac (SI) stabilization with the use of fluoroscopic image amplifiers demands a high degree of experience and has an elevated risk of screws' malpositioning.

HYPOTHESIS

Intraoperative 3D-CT scan coupled with a navigation system (O-Arm^©) can allow screw fixation accuracy while limiting the risk of complications for the treatment of posterior pelvic ring fractures.

MATERIAL AND METHODS

Patients with posterior pelvic ring fractures stabilized with percutaneous SI screws through O-Arm^© navigation from August 2008 to December 2017 were analyzed. A modified Gras classification was used to determine screws' positioning under CT visualization, and intraoperative and early postoperative complications were documented.

RESULTS

Among the 21 patients evaluated, 14 men and 7 women with a mean age of 57.8 years (range 25-91), receiving 39 screws, the rate of misplacement was low: 82% grade I, 15.4% grade II, and only 2.6% grade III. Only one patient underwent revision surgery, not because of misplacement but rather for a secondary implant loosening. No complications occurred in this series.

DISCUSSION

This study documented a large series of patients treated for pelvic ring fractures using the intraoperative 3D-CT O-Arm^© guided navigation. This surgical approach provided a precise and safe SI screw positioning with no complications.

LEVEL OF EVIDENCE

IV, Retrospective study.

Head-mounted display augmented reality to guide pedicle screw placement utilizing computed tomography

PURPOSE

Augmented reality has potential to enhance surgical navigation and visualization. We determined whether head-mounted display augmented reality (HMD-AR) with superimposed computed tomography (CT) data could allow the wearer to percutaneously guide pedicle screw placement in an opaque lumbar model with no real-time fluoroscopic guidance.

METHODS

CT imaging was obtained of a phantom composed of L1-L3 Sawbones vertebrae in opaque silicone. Preprocedural planning was performed by creating virtual trajectories of appropriate angle and depth for ideal approach into the pedicle, and these data were integrated into the Microsoft HoloLens using the Novarad OpenSight application allowing the user to view the virtual trajectory guides and CT images superimposed on the phantom in two and three dimensions. Spinal needles were inserted following the virtual trajectories to the point of contact with bone. Repeat CT revealed actual needle trajectory, allowing comparison with the ideal preprocedural paths.

RESULTS

Registration of AR to phantom showed a roughly circular deviation with maximum average radius of 2.5 mm. Users took an average of 200 s to place a needle. Extrapolation of needle trajectory into the pedicle showed that of 36 needles placed, 35 (97%) would have remained within the pedicles. Needles placed approximated a mean distance of 4.69 mm in the mediolateral direction and 4.48 mm in the craniocaudal direction from pedicle bone edge.

CONCLUSION

To our knowledge, this is the first peer-reviewed report and evaluation of HMD-AR with superimposed 3D guidance utilizing CT for spinal pedicle guide placement for the purpose of cannulation without the use of fluoroscopy.

Safety and accuracy of spinal instrumentation surgery in a hybrid operating room with an intraoperative cone-beam computed tomography

Although spinal instrumentation technique has undergone revolutionary progress over the past few decades, it may still carry significant surgery-related risks. The purpose of the present study was to assess the radiological accuracy of spinal screw instrumentation using a hybrid operating room (OR) and quantify the related radiation exposure. This retrospective study included 33 cases of complex spine fusion surgeries that were conducted using a hybrid OR with a flat panel detector (FPD) angiography system. Twelve cases (36.4%) were cervical, and 21 (63.6%) were thoracolumbar. The average number of spine fusion levels was 3 and 4.8, respectively, at the cervical and thoracolumbar spine levels. A FPD angiography system was used for intraoperative cone-beam computed tomography (CBCT) to obtain multi-slice spine images. All operations were conducted under optimized radiation shielding. Entrance surface doses (ESDs) and exposure times were recorded in all cases. A total of 313 screws were placed. Satisfactory screw insertion could be achieved in all cases with safe screw placement in 97.4% and acceptable placement in 2.6%. None of the cases showed any significant anatomical violation by the screws. The radiation exposure to the patients was absolutely consistent with the desired ESD value, and that to the surgeons, under the annual dose limit. These results suggest that the hybrid OR with a FPD angiography system is helpful to achieve safe and precise spinal fusion surgery, especially in complex cases.

Accuracy of screw fixation using the O-arm® and StealthStation® navigation system for unstable pelvic ring fractures

PURPOSE

Screw fixation for unstable pelvic ring fractures is generally performed using the C-arm. However, some studies reported erroneous piercing with screws, nerve injuries, and vessel injuries. Recent studies have reported the efficacy of screw fixations using navigation systems. The purpose of this retrospective study was to investigate the accuracy of screw fixation using the O-arm^® imaging system and StealthStation^® navigation system for unstable pelvic ring fractures.

METHODS

The participants were 10 patients with unstable pelvic ring fractures, who underwent screw fixations using the O-arm StealthStation navigation system (nine cases with iliosacral screw and one case with lateral compression screw). We investigated operation duration, bleeding during operation, the presence of complications during operation, and the presence of cortical bone perforation by the screws based on postoperative CT scan images. We also measured the difference in screw tip positions between intraoperative navigation screen shot images and postoperative CT scan images.

RESULTS

The average operation duration was 71 min, average bleeding was 12 ml, and there were no nerve or vessel injuries during the operation. There was no cortical bone perforation by the screws. The average difference between intraoperative navigation images and postoperative CT images was 2.5 ± 0.9 mm, for all 18 screws used in this study.

CONCLUSION

Our results suggest that the O-arm StealthStation navigation system provides accurate screw fixation for unstable pelvic ring fractures.

Intra-operative multi-dimensional fluoroscopy of guidepin placement prior to iliosacral screw fixation for posterior pelvic ring injuries and sacroiliac dislocation: an early case series

PURPOSE

Traditional fluoroscopic techniques during percutaneous fixation of the posterior pelvic ring at times cannot adequately visualize errant or malpositioned iliosacral screws. Intra-operative fluoroscopic techniques have been advanced using multi-dimensional fluoroscopy to generate computed tomography-like images. This provides the surgeon not only the ability to assess iliosacral screw placement, but also the opportunity to assess reduction. We present a case series of four patients in which the Ziehm RFD multi-dimensional fluoroscopy was used to assess reduction and guidepin placement prior to definitive iliosacral screw fixation.

METHODS

Four patients at our university level 1 trauma center with posterior pelvic ring disruptions were treated with percutaneous iliosacral screw fixation. Traditional fluoroscopic techniques were used during guidepin placement. Multi-dimensional fluoroscopy was performed using the Ziehm RFD 3D to assess guidepin placement and reduction prior to definitive iliosacral screw fixation.

RESULTS

Our case series highlights two patients in which multi-dimensional fluoroscopy was utilized to ensure safe placement of iliosacral screws. In one of these two patients, a change was made after reviewing the imaging as a guidepin was found to be intruded into bilateral S2 neural tunnels. We also present two patient examples in which multidimensional fluoroscopy was used to assess reduction achieved by less invasive methods, precluding the need for direct visualization using more extensive open approaches.

CONCLUSIONS

This retrospective case series demonstrates the direct impact that the Ziehm RFD 3D technology provides in surgical management of patients with complex posterior pelvic ring injuries.

Clinical Effects of the Probing Method with Depth Gauge for Determining the Screw Depth of Locking Proximal Humeral Plate

Background. The use of locking plates has gained popularity to treat proximal humeral fractures. However, the complication rates remain high. Biomechanical study suggested that subchondral screw-tip abutment significantly increased the stability of plant. We present a simple method to obtain the proper screw length through the depth gauge in elderly patients and compared the clinical effects with traditional measuring method. Methods. 40 patients were separated into two groups according to the two surgical methods: the probing method with depth gauge and the traditional measuring method. The intraoperative indexes and postoperative complications were recorded. The Constant and Murley score was used for the functional assessment in the 12th month. Results. Operative time and intraoperative blood loss indicated no statistical differences. X-ray exposure time and the patients with screw path penetrating the articular cartilage significantly differed. Postoperative complications and Constant and Murley score showed no statistical differences. Conclusions. Probing method with depth gauge is an appropriate alternative to determine the screw length, which can make the screw-tip adjoin the subchondral bone and keep the articular surface of humeral head intact and at the same time effectively avoid frequent X-ray fluoroscopy and adjusting the screws.