Intraoperative computed tomography with integrated navigation in percutaneous iliosacral screwing

Navigation versus fluoroscopy in minimalinvasive iliosacral screw placement

INTRODUCTION

When needed operative treatment of sacral fractures is mostly performed with percutaneous iliosacral screw fixation. The advantage of navigation in insertion of pedicle screws already could be shown by former investigations. The aim of this investigation was now to analyze which influence iliosacral screw placement guided by navigation has on duration of surgery, radiation exposure and accuracy of screw placement compared to the technique guided by fluoroscopy.

METHODS

68 Consecutive patients with sacral fractures who have been treated by iliosacral screws were inclouded. Overall, 85 screws have been implanted in these patients. Beside of demographic data the duration of surgery, duration of radiation, dose of radiation and accuracy of screw placement were analyzed.

RESULTS

When iliosacral screw placement was guided by navigation instead of fluoroscopy the dose of radiation per inserted screw (155.0 cGy*cm2 vs. 469.4 cGy*cm2 p < 0.0001) as well as the duration of radiation use (84.8 s vs. 147.5 s p < 0.0001) were significantly lower. The use of navigation lead to a significant reduction of duration of surgery (39.0 min vs. 60.1 min p < 0.01). The placement of the screws showed a significantly higher accuracy when performed by navigation (0 misplaced screws vs 6 misplaced screws-p < 0.0001).

CONCLUSION

Based on these results minimal invasive iliosacral screw placement guided by navigation seems to be a safe procedure, which leads to a reduced exposure to radiation for the patient and the surgeon, a reduced duration of surgery as well as a higher accuracy of screw placement.

3D-navigation for SI screw fixation - How does it affect radiation exposure for patients and medical personnel?

BACKGROUND

3D-navigation for percutaneous sacroiliac (SI) screw fixation is becoming increasingly common and several studies report great advantages of this technology. However, there is still limited clinical evidence on the efficacy regarding radiation exposure for patient and personnel.

METHODS

This is a retrospective, single-center cohort study. All patients who underwent percutaneous sacroiliac screw fixation for an injury of the posterior pelvic ring from 2014 to 2021 were screened. Inclusion criteria were: conclusive radiation dosage reports, signed informed consent, a twelve month follow up and a complete data set. Patients were stratified in two groups (3D-navigation (Group 3D-N) vs. control (Group F)) based on the imaging modality used. Primary outcomes were radiation exposure for patient and personnel. Secondary outcomes were reoperations, complications, and intraoperative precision.

RESULTS

Of 392 patients screened, 174 patients (3D-N: n = 50, F: n = 124) could be included for final analysis. We noted a significant reduction of the dose corresponding to potential radiation exposure for medical personnel (-15.3 mGy, 95 %CI: -2.1 to -28.5, p = 0.0232), but also a significant increase of the dose quantifying radiation exposure for patients (+77.0 mGy, 95 %CI: +53.3 to +100.6, p < 0.0001), when using navigation. In addition, the rate of radiographic malplacement was significantly reduced (F: 11.3% vs. 3D-N: 0 %, p = 0.0113) despite a substantial increase in transsacral screw placement (F: 19.4% vs. 3D-N: 76 %).

CONCLUSION

Our data clearly suggests that the use of 3D-navigation for percutaneous SI screw fixation decreases radiation exposure for medical personnel, while increasing radiation exposure for patients. Furthermore, intraoperative precision is improved, even in more challenging operations.

A retrospective analysis of minimally invasive internal fixation versus nonoperative conservative management of pelvic ring fragility fractures and the elderly

OBJECTIVE

We aimed to investigate the adoption of treatment patterns for hip fractures combined with minimally invasive surgical treatment of fragility fractures of the pelvis in older individuals and reviewed and analysed the treatment efficacy and feasibility.

METHODS AND DATA

From September 2017 to February 2021, 135 older individuals with fragility fractures of the pelvis were admitted to our hospital. We retrospectively analysed patients who received surgical or conservative treatments. The general preoperative data, including sex, age, disease duration, cause of injury, AO/OTA type, BMI, bone mineral density, time from injury to admission, time from injury to surgery, ASA classification, number of underlying diseases, mean bed rest, clinical fracture healing, VAS score and Majeed functional score, were recorded.

RESULTS

The mean follow-up time for all 135 patients was 10.5 ± 3.6 months. Among 135 patients, 95 survived, and 11 and 29 patients passed after the surgical (mortality rate = 17.74%) and conservative (mortality rate = 39.73%) treatments, respectively. The average follow-up time for the 95 surviving patients was 14.5 ± 1.8 months. The Majeed and VAS scores for the operation group were significantly better than those of the conservative group. The bed rest and fracture healing times were also shorter in the surgical treatment group than in the conservative group.

CONCLUSION

The use of a minimally invasive surgical treatment combined with the geriatric hip fracture treatment model to treat fragility fractures of the pelvis improved the quality of life in older patients.

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.

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

INTRODUCTION

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

HYPOTHESIS

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

MATERIAL AND METHODS

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

RESULTS

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

DISCUSSION

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

LEVEL OF PROOF

IV; Retrospective study.

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.].

[Minimally invasive lumbopelvic stabilization of sacral fracture and sacroiliac injury]

OBJECTIVE

Rapid mobilization with full weight bearing by minimally invasive fixation of Os ilium to L5 in fractures of the sacrum and disruption of the sacroiliac joint (SIJ).

INDICATIONS

Unstable injuries of the posterior pelvic ring in fractures of the sacrum and disruption of the SIJ.

CONTRAINDICATIONS

Fracture of ilium and not injury related implants in the screw trajectory, neurological deficits regarding the fracture, decubitus in the area of surgical approach.

SURGICAL TECHNIQUE

Minimally invasive screw placement in the pedicles of L5, access of ilium screw via the posterior superior iliac spine. Radiological display for the iliacal screw bearing trajectory in Os Ilium as a drop-shaped/triangle canal. Insert a Jamshidi needle orthograde in the beam path, change to guide wire and placement of iliacal screw after resection of the bone in the screw head area. Submuscular insertion of the longitudinal rods, in case of double-sided instrumentation similar procedure on the opposite side, reduction of the fracture and fixation of the rods to screws.

POSTOPERATIVE MANAGEMENT

Postoperative mobilization with full weight bearing under physiotherapeutic guidance.

RESULTS

Patients treated with lumbopelvic stabilization in our facility between 2012 and 2017 were identified via the hospital database and retrospectively evaluated. In 24 patients with median age of 60.1 years and a follow-up-time of 11.8 months, we found no implant displacement, infection and no wound healing problems. Full weight bearing was permitted in 21 of 24 cases, in 3 cases partial load bearing due to other injuries. Three patients reported moderate mechanical irritation of iliacal screws; 1 patient reported severe irritability with removal of the implants after bony healing of fracture 1 year postoperatively.

Biomechanical study of Tile C3 pelvic fracture fixation using an anterior internal system combined with sacroiliac screws

Background

How to perform minimally-invasive surgery on Tile C pelvic fractures is very difficult, and it is also a hot topic in orthopedic trauma research. We applied minimally-invasive treatment using an anterior internal fixator combined with sacroiliac screws.

Objectives

To compare the biomechanical properties of different fixation models in pelvic facture specimens, using an internal fixation system or a steel plate combined with sacroiliac screws.

Methods

Sixteen fresh adult cadaver pelvic specimens were randomly separated into four groups named A, B, C, and D. The four groups were respectively stabilized using a two-screwed, three-screwed, or four-screwed anterior internal fixator or a steel plate with sacroiliac screws. All models were tested in both standing and sitting positions. Vertical loads of 600 N were applied increasingly. Shifts of bilateral sacroiliac joints and pubis rupture were measured.

Results

The shifts in sacroiliac joints and pubis rupture in the standing position were all less than 3.5 mm, and the shifts in the sitting position were all less than 1 mm. In the standing position, the results of shifts in the sacroiliac joints were group C < group D < group B < group A. For comparisons between A:B and C:D, P > 0.05. For comparisons between A, B:C, and D, P < 0.05. The results of shifts in pubis ruptures were group D < group C < group B < group A. In the comparison between C:D, P > 0.05; for comparisons between A:B, A:C, A:D, B:C, and B:D, P < 0.05. In the sitting posture, the results of shifts in the sacroiliac joints were group C < group D < group B < group A, and the shifts in the pubis ruptures were group D < group C < roup B < group A. For comparison between C:D, P > 0.05. For comparisons between A:B, A:C, A:D, B:C, and B:D, P < 0.05.

Conclusion

Use of an anterior internal fixator combined with sacroiliac screws effectively stabilized Tile C3 pelvic fractures. The stability of specimens increased as the number of screws in the internal fixator increased.

An experimental study on the safe placement of sacroiliac screws using a 3D printing navigation module

Background

In this experimental study, we evaluated the use of digital 3D navigation printing in minimizing complications arising from sacroiliac screw misplacement.

Methods

A total of 13 adult pelvic specimens were studied using 3D navigation printing. Mimics software was used for preoperative planning and for obtaining sacrum median sagittal resection and long axis resection of the S1 pedicle center by 3D segmentation. The ideal screw path had its origin at the post-median part of the auricular surface of the sacroiliac joint, the midpoint at the mid-position of the lateral recess and outlet of the anterior sacral foramina; and the endpoint at the S1 sagittal resection. A sacroiliac screw fixed the pelvic specimens with the assistance of the navigation module. The distance between the start point (ilium surface) and endpoint (sacral median sagittal resection) of the screw path was measured after the pre- and postoperative 3D pelvis module was 3D-registered according to the standard precision range. The origin/endpoint qualified rates of the postoperative (n/26) and preoperative (26/26) screw paths were analyzed by the chi-square test.

Results

No screw misplacement occurred in the screw paths of any of the 13 pelvic specimens. The mean distance between the preoperative and postoperative origin of the screw path was 1.5415±0.6806 mm, and the mean distance between the preoperative and postoperative endpoint was 2.2809±0.4855 mm. The qualified rate of origin was 23/26 when the precision grade was 2.4 mm (P>0.05, χ²=1.41), while the qualified rate of endpoint was 21/26 when the precision grade was 2.7 mm (P>0.05, χ²=3.54).

Conclusions

In this experimental study, using a 3D printing navigation module helped attain an accurate and safe sacroiliac screw implantation.

Early Clinical Result of Computerized Navigated Screw Fixation in Treatment of Fragility Pelvic Fracture

Introduction:

Minimal invasive fixation of fragility pelvic fracture is feasible with advancement of computerized navigation. However, the clinical outcomes compared with conservative care were seldom mentioned.

Method:

This is a retrospective study comparing the outcomes of elderly with stable pelvic fracture treated conservatively or operatively using computerized navigation. Outcome parameters included pain score, analgesics requirement, length of hospital stay and complication(s), if any.

Result:

Operations were performed in 15 patients from July 2017 to November 2018. A retrospective cohort of 37 patients who were treated conservatively was recruited. In the operative group, it showed a statistically significant reduction in analgesics consumption at 4-week time only. There was significant improvement in pain score at 1-week, 4-week and 3-month time. Patients showed earlier return to premorbid walking status. No major surgical complication was noted.

Conclusion:

Treating fragility pelvic fracture with computerized navigated screw fixation achieve better pain control, reduction in analgesics requirement and earlier mobilization.

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.

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.

Computer navigation-assisted minimally invasive percutaneous screw placement for pelvic fractures

Pelvic fractures are often caused by high-energy injuries and accompanied by hemodynamic instability. Traditional open surgery has a large amount of bleeding, which is not suitable for patients with acute pelvic fracture. Navigation-guided, percutaneous puncture-screw implantation has gradually become a preferred procedure due to its advantages, which include less trauma, faster recovery times, and less bleeding. However, due to the complexity of pelvic anatomy, doctors often encounter some problems when using navigation to treat pelvic fractures. This article reviews the indications, contraindications, surgical procedures, and related complications of this procedure for the treatment of sacral fractures, sacroiliac joint injuries, pelvic ring injuries, and acetabular fractures. We also analyze the causes of inaccurate screw placement. Percutaneous screw placement under navigational guidance has the advantages of high accuracy, low incidence of complications and small soft-tissue damage, minimal blood loss, short hospital stays, and quick recovery. There is no difference in the incidence of complications between surgeries performed by new doctors and experienced ones. However, computer navigation technology requires extensive training, and attention should be given to avoid complications such as screw misplacement, intestinal injury, and serious blood vessel and nerve injuries caused by navigational drift.

Fluoroscopically guided acetabular posterior column screw fixation via an anterior approach

Objective

Safe posterior column screw fixation via an anterior approach under two-dimensional fluoroscopic control.

Indications

Anterior column with posterior hemitransverse fractures (ACPHF); transverse fractures; two-column fractures and T‑type fractures without relevant residual displacement of the posterior column after reduction of the anterior column and the quadrilateral plate.

Contraindication

Acetabular fractures requiring direct open reduction via a posterior approach; very narrow osseous corridor in preoperative planning; insufficient intraoperative fluoroscopic visualization of the anatomical landmarks.

Surgical technique

Preoperative planning of the starting point and screw trajectory using a standard pelvic CT scan and a multiplanar reconstruction tool. Intraoperative fluoroscopically controlled identification of the starting point using the anterior–posterior (ap) view. Advancing the guidewire under fluoroscopic control using the lateral–oblique view. Lag screw fixation of the posterior column with cannulated screws.

Postoperative management

Partial weight bearing as advised by the surgeon. Postoperative CT scan for the assessment of screw position and quality of reduction of the posterior column. Generally no implant removal.

Results

In a series of 100 pelvic CT scans, the mean posterior angle of the ideal posterior column screw trajectory was 28.0° (range 11.1–46.2°) to the coronal plane and the mean medial angle was 21.6° (range 8.0–35.0°) to the sagittal plane. The maximum screw length was 106.3 mm (range 82.1–135.0 mm). Twelve patients were included in this study: 10 ACPHF and 2 transverse fractures. The residual maximum displacement of the posterior column fracture component in the postoperative CT scan was 1.4 mm (0–4 mm). There was one intraarticular screw penetration and one perforation of the cortical bone in the transition zone between the posterior column and the sciatic tuber without neurological impairment.

Preoperative planning and safe intraoperative placement of iliosacral screws under fluoroscopic control

OBJECTIVE

Preoperative planning of the starting point and safe trajectory for iliosacral screw (SI screw) fixation using CT scans for safe and accurate fluoroscopically controlled percutaneous SI screw placement.

INDICATIONS

Transalar and transforaminal sacral fractures. SI joint disruptions and fracture-dislocations. Non- or minimally displaced spinopelvic dissociation injuries.

CONTRAINDICATIONS

Transiliac instabilities. Sacral fractures with neurological impairment requiring decompression. Relevant residual displacement after closed reduction attempts. Insufficient fluoroscopic visualization of the anatomical landmarks of the upper sacrum.

SURGICAL TECHNIQUE

Preoperative planning of the starting point and the safe screw trajectory using CT scans and two-dimensional multiplanar reformation tools. Fluoroscopically guided identification of the starting point using the lateral view according to preoperative planning. Advancing the guidewire under fluoroscopic control using inlet and outlet views according to the planned trajectory. Predrilling and placement of 6.5 mm cannulated screws.

POSTOPERATIVE MANAGEMENT

Weightbearing as tolerated using crutches. Immediate CT scan in case of postoperative neurological impairment. Generally no screw removal.

RESULTS

Fifty-nine screws were placed in 34 patients using the described technique. There were 2 cases of screw malpositioning (anatomical landmarks inadequately identified and fluoroscopically controlled SI screw fixation should thus not have been performed at all; in a case with sacral dysmorphism, preoperative planning suggested a posterior and/or caudal S1 starting point, respectively, but intraoperatively, selection of a different starting point and screw trajectory resulted in screw malpositioning with iatrogenic L5 nerve palsy).

[Precise sacroiliac joint screw insertion without computed tomography, digital volume tomography or navigation systems]

OBJECTIVE

Improvement of sacroiliac positioning of screws by detailed preoperative planning with a DICOM (Digital Imaging and Communications in Medicine-the international standard to store and process medical imaging information) workstation in the absence of advanced technical facilities like intraoperative computer tomography (CT), digital volume tomography (DVT) or a navigation system.

INDICATIONS

Mono- or bilateral non- or minor displaced, longitudinal sacral fractures type Denis I and II and pelvic ring fractures (Orthopedic Trauma Association) OTA type B possibly in combination with a ventral procedure.

CONTRAINDICATIONS

Displaced sacral fractures type Denis II and III, fractures with central comminution and circulatory unstable patients to be stabilized in the context of emergency care.

SURGICAL TECHNIQUE

Preoperative calculation of virtual conventional standard view X‑rays with the CT dataset using common DICOM software (e.g., Siemens via® or Sectra®). Typical landmarks such as screw entry point and end point are projected into the virtual X‑rays. Intraoperative navigation is performed by comparing the virtual standard views with fluoroscopic images of the C‑arm, thereby, simplifying the operative procedure.

POSTOPERATIVE MANAGEMENT

Postoperative CT scan, pain adapted partial weight bearing and X‑rays of the pelvic ring after 6 and 12 weeks.

RESULTS

Over a 13 month period, an orthopedic surgeon inserted 26 sacroiliac screws in 19 patients utilizing the described method. Postoperative CT scans revealed that all except three screws were precisely positioned without any bone perforation. Of these three screws one had a grade one perforation and two had a grade two perforation according to Smith. No revision was necessary and no neurological deficits were detected. The operating time was on average 33 min and duration of radiation 3.8 min.

Comparative Study of Percutaneous Sacroiliac Screw with or without TiRobot Assistance for Treating Pelvic Posterior Ring Fractures

Objectives

To analyze the curative effect of TiRobot surgical robotic navigation and location system‐assisted percutaneous sacroiliac screw fixation and percutaneous sacroiliac screw by traditional fluoroscopy, and to summarize the safety and benefits of TiRobot.

Methods

A total of 91 patients with pelvic posterior ring fractures from December 2015 to February 2018 were included in this study. According to the surgical methods selected by the patients, the patients were divided into a TiRobot surgical robotic navigation and location system group (TiRobot group) and a percutaneous sacroiliac screw fixation group (traditional group). Statistical indicators included the number of sacroiliac screws, the time of planning the sacroiliac screw path, fluoroscopy frequency, fluoroscopy time, operation time, length of incision, blood loss, anesthesia time, the healing process of skin incisions, and fracture healing time. Fracture reduction was evaluated according to the maximum displacement degree at the inlet and outlet view X‐ray or CT. Matta standard was used to evaluate fracture reduction. At the last follow‐up, the Majeed function system was used to evaluate the function.

Results

All patients were followed up for 8 to 32 months. A total of 66 sacroiliac screws were implanted in the TiRobot group. A total of 43 sacroiliac screws were implanted in the traditional group. There were statistically significant differences in terms of fluoroscopy frequency, fluoroscopy time, operation time, incision length, anesthesia time, and blood loss between the two groups; the TiRobot group was superior to the traditional group. The healing time of the TiRobot group and the traditional group was 4.61 ± 0.68 months (range, 3.5–6.3 months) and 4.56 ± 0.78 months (range, 3.4–6.2 months), respectively, and there was no statistical difference. Postoperatively, by Matta standard, the overall excellent and good rate of fracture reduction was 89.28% and 88.57%, respectively. At the last follow‐up, by Majeed function score, the overall excellent and good rate was 91.07% and 91.43%. There was no statistical difference between the two groups.

Conclusion

Sacroiliac screw implantation assisted by TiRobot to treat the posterior pelvic ring fractures has the characteristics of less trauma, shorter operation time, and less blood loss. TiRobot has the characteristics of high safety and accuracy and has great clinical application value.

Safe corridor for iliosacral and trans-sacral screw placement in Indian population: A preliminary CT based anatomical study

OBJECTIVES

Nonsurgical management of unstable pelvic ring injuries is associated with poor outcomes. Posterior pelvic ring injuries include sacroiliac joint disruption and sacral fractures or a combination of the two. Morbidity is high in non-operatively managed patients. Screw fixation is being increasingly used to manage unstable posterior pelvic injuries. Limitations include a steep learning curve and potential for neurovascular injury. This is the first study in Indian population to describe the safe corridor for screw placement and check the feasibility of screw in both upper and lower sacral segments.

METHODS

This study involved retrospective analysis of 105 pelvic CT scans of patients admitted to the emergency department of a Level 1 trauma centre. Vertical height at the level of constriction (vestibule) of S1 and S2 was measured in coronal sections and anteroposterior width of constrictions was measured in axial sections. We created a trajectory for 7.3 mm cylinder keeping additional 2 mm free bony corridor around it and confirmed that bony limits were not breached in axial, coronal and sagittal sections. Whenever there was breach in bony limit we checked applicability of 6.5 mm screw.

RESULTS

The vertical height and anteroposterior width of vestibule/constriction of S1 was significantly higher in males, whereas S2 vestibule height and width were similar in males and females. Both male and female pelves were amenable to S1 Trans-sacral and S1 Iliosacral screw fixation with a 7.3 mm screw when a safe corridor of 2 mm was kept on all sides. However, when S2 segment was analysed, only 42.9% of male pelves and 25.7% of female pelves were amenable to insertion of trans-sacral 7.3 mm screw.

CONCLUSION

An individualized approach is necessary and each patient's CT must be carefully studied before embarking on sacroiliac screw fixation in Indian population.

New advances in intra-operative imaging in trauma

The invention of flat-panel detectors led to a revolution in medical imaging. The major benefits of this technology are a higher image quality and dose reduction. Flat-panel detectors have proved to be superior to standard C-arms (= C-arm with radiograph source and image intensifier).

Cone-beam computed tomography (cone-beam CT) is a 3D data set, which can be acquired with a flat-panel detector. The cone-shaped beam is used for 3D data generation. For cone-beam CT acquisition, the flat-panel detector rotates around the patient lying on the operating table. Intra-operative cone-beam CT can be a very helpful tool in orthopaedic surgery. Immediate control of fracture reduction and implant positioning in high image quality can reduce the need for secondary revision surgery due to implant malposition.

In recent years there has been a revival of standard fan beam CT technology in operating rooms. Fixed and mobile systems are available. Fixed systems are typically placed on a sliding gantry. Different mobile intra-operative CT scanners were recently introduced. Due to their mobility, they are not bound to a specific operating room. The use of standard intra-operative CT scanners results in high 3D image quality but, in comparison with a cone-beam CT scanner, fluoroscopy is not possible.

The introduction of flat-panel detectors has led to improvements in intra-operative image quality combined with dose reduction. The possibility of high-quality 3D imaging in combination with navigation can assure optimal implant placement. Due to immediate control of the osteosynthesis, revision surgery at a later time can be prevented.

Cite this article: EFORT Open Rev 2018;3 DOI: 10.1302/2058-5241.3.170055

Percutaneous sacroiliac screw versus anterior plating for sacroiliac joint disruption: A retrospective cohort study

BACKGROUND

Sacroiliac joint disruption (SJD) is a common cause of pelvic ring instability. Clinically, percutaneous unilateral S1 sacroiliac screw and anterior plating are always applied to manage SJD. The objective of this study is to elaborate their respective therapeutic traits.

MATERIALS AND METHODS

Patients with SJD fixed with unilateral S1 sacroiliac screw or anterior plating from June 2011 to June 2015 were recruited into this study and were divided into two groups: group A (unilateral sacroiliac screw) and group B (anterior plating). Surgical time, blood loss, frequency of intraoperative fluoroscopy and complications were reviewed. Postoperative radiograph and CT were conducted to assess the reduction quality. Fracture healing was evaluated by radiograph performed at each follow-up. Majeed score was recorded at the final follow-up to assess the functional outcome.

RESULTS

Thirty-eight patients were included in group A and thirty-two patients in group B in this study. There was no significant difference in the demographic data of the two groups. A significant difference existed in the results for average operation time (P = .022) and blood loss (P = .000) between group A and group B. The mean frequency of intraoperative fluoroscopy was 15.82 in group A and 3.94 in group B (P = .000). All the fractures healed in this study. The rates of satisfactory reduction quality and functional outcome showed no significant difference between the two groups (P > .05). The complication rate was 15.79% (6/38) in group A and 9.38% (3/32) in group B (P = .660).

CONCLUSION

Compared with anterior plating, percutaneous unilateral S1 sacroiliac screw usage is less invasive; however, more intraoperative X-ray exposure and permanent neurologic damage may accompany this procedure.

Percutaneous Placement of Iliosacral Screws Under the Guidance of Axial View Projection of the S1 Pedicle: a Case Series

The aim of this study was to evaluate the safety and efficacy of percutaneous placement of iliosacral screws under the guidance of axial view projection of the S1 pedicle clinically. This case series includes 58 consecutive unstable pelvic injury patients, which were treated with iliosacral screws between July 2011 and July 2016. Patients were divided into two groups: normal sacrum (n = 31) and dysmorphic sacrum (n = 27). A single orthopedic surgeon operated on all patients, with percutaneous placement of iliosacral screws under the guidance of axial view projection of the S1 pedicle. The time needed for screw insertion and the radiation exposure time were recorded. Chi-squared test and Student t-test were used to analyze the differences between the two groups. Sacral dysmorphism was present in 47% of patients. The median time for screw insertion and radiation exposure time in these two groups showed no statistical difference (P > 0.05). No clinical complications or malpositioned screws occurred in any case. Preoperative pelvic CT is necessary to determine the sacral osseous anatomy. In patients with either a normal or dysmorphic sacrum, iliosacral screws can be placed by this method with less radiation exposure and complications than in the conventional method.

Percutaneous screw fixation of the iliosacral joint: A case-based preoperative planning approach reduces operating time and radiation exposure

INTRODUCTION

A preoperative planning approach for percutaneous screw fixation of the iliosacral joint provides specific entry points (EPs) and aiming points (APs) of intraosseous screw pathways (as defined by CT scans) for lateral fluoroscopic projections used intraoperatively. The potential to achieve the recommended EPs and APs, to obtain an ideal screw position (perpendicular to the iliosacral joint), to avoid occurrence of extraosseous screw misplacement, to reduce the operating time and the radiation exposure by utilizing this planning approach have not been described yet.

METHODS

On preoperative CT scans of eight human cadaveric specimen individual EPs and APs were identified and transferred to the lateral fluoroscopic projection using a coordinate system with the zero-point in the center of the posterior cortex of the S1 vertebral body (x-axis parallel to upper S1 endplate). Distances were expressed in relation to the anteroposterior distance of the S1 upper endplate (in%). In each specimen on one side a screw was placed with provided EP and AP (New Technique) whereas at the contralateral side a screw was placed without given EP and AP (Conventional Technique). Both techniques were compared using postoperative CT scans to assess distances between predefined EPs and APs and the actually obtained EPs and APs, screw angulations in relation to the iliosacral joint in coronal and axial planes and the occurrence of any extraosseous screw misplacement. The "operating time (OT)" and the "time under fluoroscopy (TUF)" were recorded. Statistical analysis was performed by the Wilcoxon signed-rank test.

RESULTS

EPs were realized significantly more accurate using the new technique in vertical direction. The screw positions in relation to the iliosacral joint showed no significant difference between both techniques. Both techniques had one aberrantly placed screw outside the safe corridor. The (mean±SD) "OT" and the (mean±SD) "TUF" were significantly decreased using the new technique compared to the conventional technique (OT: 7.6±2min versus 13.1±5.8min, p=0.012; TUF: 1.5±0.8min versus 2.2±1.1min).

CONCLUSION

The presented preoperative planning approach increases the accuracy in percutaneous screw fixation of the iliosacral joint, reduces operating time and minimizes radiation exposure to patient and staff.

Accurate fixation of plates and screws for the treatment of acetabular fractures using 3D-printed guiding templates: An experimental study

OBJECTIVE

To investigate the feasibility of the use of 3D-printed guiding templates for accurate placement of plates and screws for internal fixation of acetabular fractures.

METHODS

3D models of the pelvises of 14 adult cadavers were reconstructed using computed tomography (CT). Twenty-eight acetabular fractures were simulated and placement positions for plates and screw trajectories were designed. Bending module was obtained by 3D cutting; guiding template was manufactured using 3D printing, and the plate was pre-bent according to the bending module. Plates and screws were placed in cadaveric pelvises using the guiding template, and 3D model was reconstructed using CT. The designed and real trajectories were matched using 3D registration including the coordinates (entry and exit points) of designed trajectory. The number of qualified points with different accuracy levels was compared using Chi-squared test.

RESULTS

Sixty-four plates and 339 screws were placed with no cortical breach. The absolute difference of the X, Y, and Z coordinates between the designed and real entry points were 0.52±0.45, 0.43±0.36, and 0.53±0.44mm, respectively. The corresponding values for the exit points were 0.83±0.67, 1.22±0.87, and 1.26±0.83mm, respectively. With an accuracy degree ≥1.9mm for the entry points and ≥3.8mm for the exit points, there was no significant difference between the designed and the real trajectories.

CONCLUSION

The 3D-printed guiding template helped achieve accurate placement of plates and screws in the pelvis of adult cadavers.

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.

2D versus 3D fluoroscopy-based navigation in posterior pelvic fixation: review of the literature on current technology

PURPOSE

Percutaneous sacroiliac (SI) fixation of unstable posterior pelvic ring injuries is a widely accepted procedure. The complex sacral anatomy with narrow osseous corridors for SI screw placement makes this procedure technically challenging. Techniques are constantly evolving as a result of better understanding of the posterior pelvic anatomy. Recently developed tools include fluoroscopy-based computer-assisted navigation, which can be two-dimensional (2D) or three-dimensional (3D). Our goal is to determine the relevant technical considerations and clinical outcomes associated with these modalities by reviewing the published research. We hypothesize that 3D fluoroscopy-based navigation is safer and superior to its 2D predecessor with respect to lower radiation dose and more accurate SI screw placement.

METHODS

We searched four medical databases to identify English-language studies of 2D and 3D fluoroscopy-based navigation from January 1990 through August 2015. We included articles reporting imaging techniques and outcomes of closed posterior pelvic ring fixation with percutaneous SI screw fixation. Injuries included in the study were sacral fractures (52 patients), sacroiliac fractures (88 patients), lateral compression fractures (20 patients), and anteroposterior compression type pelvic fractures (8 patients). We excluded articles on open reduction of posterior pelvic ring injuries and solely anatomic studies. We then reviewed these studies for technical considerations and outcomes associated with these technologies.

RESULTS

Six studies were included in our analysis. Results of these studies indicate that 3D fluoroscopy-based navigation is associated with a lower radiation dose and lower rate of screw malpositioning compared with 2D fluoroscopy-based systems.

CONCLUSIONS

It may be advantageous to combine modern imaging modalities such as 3D fluoroscopy with computer-assisted navigation for percutaneous screw fixation in the posterior pelvis.

A simple approach for the preoperative assessment of sacral morphology for percutaneous SI screw fixation

BACKGROUND

Percutaneous sacroiliac screw fixation under fluoroscopic control is an effective method for posterior pelvic ring stabilization. However, sacral dysmorphism has a high risk of L5 nerve injury. This study describes a simple method for the preoperative assessment of the sacral morphology using CT scans with widely available tools.

MATERIALS AND METHODS

CT scans of 1000 patients were analyzed. True inlet, outlet, and lateral views of the sacrum were obtained using a two-dimensional reconstruction tool to align the sacrum in a reproducible manner. Corridor morphology in the inlet view was measured to calculate different morphological types: (1) Ascending type, (2) Horizontal type, and (3) Descending type. In a second step, the corridor was analyzed for the presence of an anterior indentation of the sacrum between the SI joint and the midsagittal plane with proximity to the nerve root L5, which, therefore, may be harmed during screw misplacement.

RESULTS

A notch was found in the majority of cases with relative frequencies ranging from 69 % (upper quartile of S1) to 95 % (upper quartile of S2). Descending types were, by far, the most frequent corridor type with one exception: In the upper quartile of S1, the ascending type was the most frequent corridor (71 %). Horizontal types were less frequent with a relative incidence between 2 and 14 %.

DISCUSSION

This study should increase the awareness for sacral dysmorphism, emphasize the importance of a preoperative assessment of the osseous corridor, and provide a simple method for the preoperative assessment with widely available tools.

Precision insertion of percutaneous sacroiliac screws using a novel augmented reality-based navigation system: a pilot study

PURPOSE

Augmented reality (AR) enables superimposition of virtual images onto the real world. The aim of this study is to present a novel AR-based navigation system for sacroiliac screw insertion and to evaluate its feasibility and accuracy in cadaveric experiments.

METHODS

Six cadavers with intact pelvises were employed in our study. They were CT scanned and the pelvis and vessels were segmented into 3D models. The ideal trajectory of the sacroiliac screw was planned and represented visually as a cylinder. For the intervention, the head mounted display created a real-time AR environment by superimposing the virtual 3D models onto the surgeon's field of view. The screws were drilled into the pelvis as guided by the trajectory represented by the cylinder. Following the intervention, a repeat CT scan was performed to evaluate the accuracy of the system, by assessing the screw positions and the deviations between the planned trajectories and inserted screws.

RESULTS

Post-operative CT images showed that all 12 screws were correctly placed with no perforation. The mean deviation between the planned trajectories and the inserted screws was 2.7 ± 1.2 mm at the bony entry point, 3.7 ± 1.1 mm at the screw tip, and the mean angular deviation between the two trajectories was 2.9° ± 1.1°. The mean deviation at the nerve root tunnels region on the sagittal plane was 3.6 ± 1.0 mm.

CONCLUSIONS

This study suggests an intuitive approach for guiding screw placement by way of AR-based navigation. This approach was feasible and accurate. It may serve as a valuable tool for assisting percutaneous sacroiliac screw insertion in live surgery.

Percutaneous iliosacral screw fixation after osteoporotic posterior ring fractures of the pelvis reduces pain significantly in elderly patients

INTRODUCTION

Osteoporotic posterior ring fractures of the pelvis are common injuries in the elderly, but the treatment of these fractures still remains controversial. Percutaneous iliosacral screw fixation is one surgical option if conservative treatment cannot provide sufficient pain reduction. The aim of this study is to provide short-term results of elderly patients with percutaneous screw fixation.

METHODS

30 patients with posterior ring fractures were treated between 12/2009 and 01/2014 with percutaneous iliosacral screw fixation. Patients' mean age was 78.4 years. Concerning short-term outcome, we focused on initial pain level and postoperative pain reduction together with intra- and postoperative complications.

RESULTS

The average hospital stay was 23.7 days, with surgical treatment performed after an average of 9.2 days. 90% of our patients were female. All 30 patients had a lower level of pain at discharge compared with admission or immediately prior to surgery. The difference in pain level at admission compared with the pain level upon discharge showed a mean reduction from 6.8 to 1.8 with a statistically significant change (P≤0.001). 24 of 30 patients had no registered complications, one screw malpositioning with postoperative nerve irritation occurred.

DISCUSSION

Conventional percutaneous iliosacral screw fixation is a successful operative treatment for elderly patients with persistent lower back pain after unstable posterior ring fractures of the pelvis. Intra- and postoperative complications are rare, so this treatment can be regarded as a safe procedure.

LEVEL OF EVIDENCE

IV (retrospective study).

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.