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

Transiliac-transsacral Screws: What is the Required Implant Length for Adequate Percutaneous Fixation of the Posterior Pelvic Ring?

Objective  Brazilian orthopedic surgeons experience the unavailability of long screws allowing percutaneous fixation of the posterior pelvic ring in transiliac-transsacral (TI-TS) configuration. The objective of the present study is to measure the lenght of the osseous fixation pathways available for TI-TS fixation in a population sample to infer the required implant length. Methods  We retrospectively assessed patients undergoing computed tomography (CT), initially identifying the existence of a potential osseous fixation pathway (POFP) in S1, S2 and S3. Each POFP was measured from the external cortex of the iliac bone to the external cortex of the contralateral iliac bone on axial CT images. Results  The analysis comprised a sample of 180 cases. A POFP was identified in S1 in 116 (64.4%) cases, in S2 in 178 (98.9%) cases, and in S3 in 16 (8.9%) cases. The median (interquartile range - IQR) POFP measurement in S1 was 153 (148-161) mm, ranging from 135 mm to 179 mm. In S2, the median (IQR) POFP measurement was 136 (131-144) mm, ranging from 114 to 160 mm. In S3, the median (IQR) POFP measurement was 120.5 (115-126) mm, ranging from 110 to 131 mm. Conclusions  We demonstrated that the maximum lengths of the osseous fixation pathways identified in our sample would require screws up to 180 mm in length, with a clear dissociation between the values measured and the longer screws currently commercialized in our setting.

Occupational Radiation Exposure During Intraoperative 3-Dimensional Fluoroscopy in Pelvis and Acetabular Surgery

OBJECTIVES

To quantify the occupational radiation exposure with a 3-dimensional (3D) fluoroscopic machine during routine use in pelvic and acetabular surgery and to determine whether the additional radiation exposure encountered with the 3D fluoroscopic spin is within previously accepted limits.

METHODS

DESIGN

Prospective cohort study.

SETTING

Level I trauma center.

PATIENT SELECTION CRITERIA

All patients undergoing 3D fluoroscopy intraoperatively during pelvis (OTA/AO 61B,C) or acetabular (OTA/AO 62A-C) surgery between April 2021 and July 2021.

OUTCOME MEASURES AND COMPARISONS

Radiation dose at standardized locations around the operating room during the spin portion of the 3D fluoroscopy.

RESULTS

Seventy-six 3D spins were performed on 69 patients during the study period. The average emitted radiation dose from the machine for the routine fluoroscopy portion of the case was 74.5 mGy. The average displayed radiation dose in the air for the spin portion of the case was 39.9 mGy, an average of 53.6% less radiation than the routine fluoroscopy portion. For the spin portion, the average radiation exposure seen by the patient was 3.42 mGy (centered on the patient) and the average maximal exposure in the room was 0.062 mGy. Minimal radiation was detected outside the operating room doors.

CONCLUSIONS

The radiation exposure encountered by operating room personnel with 3D fluoroscopy appears to be within safe occupational limits. The marginal increase in radiation exposure during pelvic and acetabular surgery should not discourage the use of 3D imaging intraoperatively.

LEVEL OF EVIDENCE

Level IV, Case Series.

A feasibility cadaver study for placing screws in various pelvic osseous fracture pathways using a robotic arm

INTRODUCTION

The use of a robotic system for the placement of pedicle screws in spine surgeries is well documented in the literature. However, there is only a single report in the United States describing the use of a robotic system to place two screws in osseous fixation pathways (OFPs) commonly used in the treatment of pelvic and acetabular fractures in a simulated bone model. The purpose of this study was to demonstrate the use of a robotic system to place screws in multiple, clinically relevant OFPs in a cadaveric model and to quantitatively measure accuracy of screw placement relative to the preoperative plan.

METHODS

A single cadaveric specimen was obtained for the purpose of this study. All surrounding soft tissues were left intact. Screws were placed in OFPs, namely iliosacral (IS), trans-sacral (TS), Lateral Compression-II (LC-II), antegrade anterior column (AC) and antegrade posterior column (PC) of the right hemipelvis using standard, fluoroscopically assisted percutaneous or mini-open technique. Following the placement of screws into the right hemipelvis using standard techniques, screws were planned and placed in the same OFPs of the contralateral hemipelvis using the commercially available ExcelsiusGPS® robotic system (Globus Medical Inc., Audubon, PA). After robotic-assisted screw placement, a post-procedure CT scan was obtained to evaluate actual screw placement against the pre-procedure plan. A custom-made image analysis program was devised to measure screw tip/tail offset and angular offset on axial and sagittal planes.

RESULTS

For different OFPs, the mean tip offset, tail offset and angular offsets were 1.6 ± 0.9 mm (Range 0.0-3.6 mm), 1.4 ± 0.4 mm (Range 0.3-2.5 mm) and 1.1 ± 0.4° (Range 0.5-2.1), respectively.

CONCLUSION

In this feasibility study, surgeons were able to place screws into the clinically relevant fracture pathways of the pelvis using ExcelsiusGPS® for robotic-assisted surgery. The measured accuracy was encouraging; however, further investigation is needed to demonstrate that robotic-assisted surgery can be used to successfully place the screws in the bony corridors of the pelvis to treat traumatic pelvic injuries.

Multidimensional Fluoroscopy to Assess Closed Reduction in Displaced Young Femoral Neck Fractures: A Report of 3 Cases

CASE

The authors present 3 physiologically young patients with displaced femoral neck fractures who underwent initial closed reduction and provisional fixation. Multidimensional fluoroscopy was used to assess fracture reduction before definitive fixation, with 1 patient requiring an open approach because of inadequate fracture reduction after closed attempts.

CONCLUSION

Displaced femoral neck fractures in young patients remain difficult injuries to treat. Reduction quality is a significant predictor of patient outcomes. Intraoperative multidimensional fluoroscopy provides treating surgeons with a tool to assess fracture reduction after closed reduction maneuvers and allows for intraoperative treatment adjustment as needed.

Intraoperative Imaging Challenges During Pelvic Ring Disruptions and Acetabular Fracture Surgery

Achieving high-quality intraoperative imaging is crucial for successful pelvic ring and acetabular fracture surgery, yet it remains clinically challenging. Due to the complex anatomy of the pelvic ring and acetabulum, it is necessary to obtain multiple images oriented in different planes to reliably confirm reduction accuracy and implant positioning. Intraoperative image quality can be compromised by factors such as patient body habitus, bowel gas, abdominal packing, contrast dye, and nonstandardized language between surgeon and radiology technician. This article reviews common intraoperative imaging challenges encountered during pelvic ring and acetabular fracture surgery, while providing practical and evidence-based solutions and prevention strategies.

Use of 3D Fluoroscopy to Assist in the Reduction and Fixation of Pelvic and Acetabular Fractures: A Safety and Quality Case Series

SUMMARY

Multidimensional fluoroscopy has been increasingly used in orthopaedic trauma to improve the intraoperative assessment of articular reductions and implant placement. Owing to the complex osteology of the pelvis, cross-sectional imaging is imperative for accurate evaluation of pelvic ring and acetabular injuries both preoperatively and intraoperatively. The continued development of fluoroscopic technology over the past decade has resulted in improved ease of intraoperative multidimensional fluoroscopy use in pelvic and acetabular surgery. This has provided orthopaedic trauma surgeons with a valuable tool to better evaluate reduction and fixation at different stages during operative treatment of these injuries. Specifically, intraoperative 3D fluoroscopy during treatment of acetabulum and pelvis injuries assists with guiding intraoperative decisions, assessing reductions, ensuring implant safety, and confirming appropriate fixation. We outline the useful aspects of this technology during pelvic and acetabular surgery and report its utility with a consecutive case series at a single institution. The added benefits of this technology have improved the ability to effectively manage patients with pelvis and acetabulum injuries.

Assessment of sacral osseous fixation pathways for same-level dual transiliac-transsacral screw insertion

INTRODUCTION

The purpose of this study is to (1) describe a pre-operative planning technique using non-reformatted CT images for insertion of multiple transiliac-transsacral (TI-TS) screws at a single sacral level, (2) define the parameters of a sacral osseous fixation pathway (OFP) that will allow for insertion of two TI-TS screws at a single level, and (3) identify the incidence of sacral OFPs large enough for dual-screw insertion in a representative patient population.

METHODS

Retrospective review at a level-1 academic trauma center of a cohort of patients with unstable pelvic injuries treated with two TI-TS screws in the same sacral OFP, and a control cohort of patients without pelvic injuries who had CT scans for other reasons.

RESULTS

Thirty-nine patients had two TI-TS screws at S1. Eleven patients, all with dysmorphic osteology, had two TI-TS screws at S2. The average pathway size in the sagittal plane at the level the screws were placed was 17.2 mm in S1 vs 14.4 mm in S2 (p = 0.02). Twenty-one patients (42%) had screws that were intraosseous and 29 (58%) had part of a screw that was juxtaforaminal. No screws were extraosseous. The average OFP size of intraosseous screws was 18.1 mm vs. 15.5 mm for juxtaforaminal screws (p = 0.02). Fourteen millimeters was used as a guide for the lower limit of the OFP for safe dual-screw fixation. Overall, 30% of S1 or S2 pathways were ≥ 14 mm in the control group, with 58% of control patients having at least one of the S1 or S2 pathways ≥ 14 mm.

CONCLUSIONS

OFPs ≥ 7.5 mm in the axial plane and 14 mm in the sagittal plane on non-reformatted CT images are large enough for dual-screw fixation at a single sacral level. Overall, 30% of S1 and S2 pathways were ≥ 14 mm and 58% of control patients had an available OFP in at least one sacral level.

Imaging of Pelvic and Acetabular Trauma: Part 1, Osseous Findings

Pelvic ring injuries and acetabular fractures are complex injuries and are often challenging to treat for a number of reasons. Orthopaedic trauma surgeons critically evaluate pelvic radiographs and CT images to generate an appropriate detailed injury and patient-specific preoperative plan. There are numerous crucial osseous details that surgeons should be aware of. Often, some of the most important factors that affect patients in treatment timing decisions, assessing reduction strategies, and deciding and inserting fixation constructs may be subtle on preoperative imaging. The radiographic and CT imaging findings covered subsequently should be sought out and appreciated preoperatively. Combining all the available osseous information helps the surgeon predict potential pitfalls and adjust surgical plans before incision. Ensuring a methodical and meticulous imaging review allows for the development of a detailed preoperative plan and helps avoid intraoperative missteps. This process will inherently streamline the surgical procedure and optimize the patient's surgical care. Maximizing the accuracy of the preoperative planning process can streamline the treatment algorithm and ultimately contribute to the best possible clinical outcome.

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.

A standardized method of measuring screw breach on postoperative computed tomography scans following percutaneous fixation of the posterior pelvic ring

PURPOSE

To assess the reliability of a standardized measurement of screw breach on postoperative computed tomography (CT) scans following percutaneous fixation of the posterior pelvic ring.

METHODS

Three orthopedic trauma surgeons independently utilized a standardized method of measuring posterior pelvic ring screw breaches on post-operative CT scan images. Breaches were measured as a continuous variable on sagittal images reformatted to be perpendicular to the screw on axial images. The inter-rater and intra-rater reliability of screw breach distance measurements was assessed.

RESULTS

Measurements were performed on 42 screws in 20 patients. Screw types included S1-iliosacral (IS) (n = 16), S1-transsacral (TS) (n = 8), S2-IS (n = 2), and S2-TS (n = 16). Patients with varying degrees of screw breaches were chosen to test measurements across breach severities, including 0 mm (n = 10), ≤ 2 mm (n = 12), > 2 to 4 mm (n = 11), and > 4 mm (n = 9). The mean difference and 95% confidence interval (CI) between screw breach measurements between the three surgeons was - 0.13 mm (CI - 0.48 to 0.20), 0.05 mm (CI - 0.6 to 0.7), and 0.18 mm (CI - 0.47 to 0.85), respectively. The inter-rater reliability of the measurements was considered excellent (intraclass correlation coefficient (ICC), 0.93). The mean intra-rater reliability for the observers was considered good (ICC 88.5, CI 82 to 95).

CONCLUSIONS

This simple standardized method of measuring screw breaches had excellent inter-rater reliability and would support comparisons of screw breach severity across studies.

LEVEL OF EVIDENCE

Level III.

Risk factors for screw breach and iatrogenic nerve injury in percutaneous posterior pelvic ring fixation

Background

Percutaneous screw fixation of the posterior pelvic ring is technically demanding and can result in cortical breach. The purpose of this study was to examine risk factors for screw breach and iatrogenic nerve injury.

Methods

A retrospective review at a single level-one trauma center identified 245 patients treated with 249 screws for pelvic ring injuries with postoperative computed tomography (CT) scans. Cortical screw breach, iatrogenic nerve injury, and associated risk factors were evaluated.

Results

There were 86 (35%) breached screws. The breach rate was similar between screw types (33% S1-iliosacral (S1-IS), 44% S1-transsacral (S1-TS), 31% S2-IS, and 30% S2-TS) and was not associated with patient characteristics, Tile C injuries, or corridor size or angle. The overall rate of screw revision for screw malpositioning was 1.2% (3/249). Iatrogenic nerve injuries occurred in 8 (3.2%) of the 249 screws. Screws that caused iatrogenic nerve injuries had greater screw breach distances (5.4 vs. 0 mm, MD 5, CI 2.3 to 8.7, p < 0.0001), were more likely to be S1-IS screws (88% vs. 47%, PD 40%, CI 7 to 58%, p = 0.006), more likely to be placed in Tile C injuries (75% vs. 44%, PD 31%, CI -3 to 55%, p = 0.04), and there was a trend for having a screw corridor size <10 mm (75% vs. 47%, PD 28, CI -6 to 52%, p = 0.06). Of the 7 iatrogenic nerve injuries adjacent to screw breaches, two nerve injuries recovered after screw removal, three recovered with screw retention, and two did not recover with screw retention.

Conclusion

Screw breaches were common and iatrogenic nerve injuries were more likely with S1-IS screws. Surgeons should maintain a high degree of caution when placing these screws and consider removal of any breached screw associated with nerve injury.

Multimodal Neuroelectrophysiological Monitoring Combined with Robot-Assisted Placement of a Transiliac–Transsacral Screw for the Treatment of Transforaminal Sacral Fractures

Objective

This study aimed to evaluate the safety and efficacy of the fixation of transforaminal sacral fractures using TiRobot-assisted transiliac-transsacral (TITS) screws under multimodal neuroelectrophysiological monitoring (MNM).

Methods

From January 2019 to May 2021, 22 patients (17 male and 5 female patients) with transforaminal sacral fractures who were treated with closed reduction and placement of TiRobot-assisted TITS screws under MNM were retrospectively evaluated. The average age of the patients was 43.32 ± 11.40 years (range: 19–63). The patients received MNM, including somatosensory-evoked potentials (SEPs), motor-evoked potentials (MEPs), and electromyographic monitoring (EMG), prior to surgery, during closed reduction and the placement of the guidewire and TITS screw, and at the end of surgery. The operation was adjusted according to the MNM results.

Results

Overall, 22 TITS screws were inserted in 22 patients, including 5 TITS screws in the S1 body and 17 TITS screws in the S2 body. The average time needed for screw placement was 27.95 ± 6.84 mins, and the average frequency of X-ray fluoroscopy exposures was 31.00 ± 5.56 for each patient. Anterior ring fixation was performed in 4 patients using an external fixator, in 5 patients using cannulated screws, and in 13 patients using reconstruction plates. The mean follow-up time was 14.46 ± 2.46 months (12–20 months). Tornetta and Matta radiographic outcomes were excellent in 10 patients, good in 9 patients, fair in 2 patients, and poor in 1 patient. The proportion of excellent and good ratings was 86.36%. At the final follow-up, the average Majeed score was 82.18 ± 14.52, with clinical outcomes that were excellent in 9 patients, good in 9 patients, fair in 1 patient, and poor in 3 patients. The proportion of excellent and good ratings was 82.82%. Preoperatively, the amplitude of the SEP on the injured side was lower than that on the contralateral side before reduction in 9 patients (>50%). In this study, no screw was mistakenly inserted into the sacral canal, and no surgical site infection occurred.

Conclusion

MNM combined with TiRobot assistance can safely implant TITS screws and can effectively identify the neurological function of patients under anesthesia and reduce iatrogenic nerve injury.

The Utility of the Hyperinlet View in Posterior Fixation of Pelvic Ring Injuries

Percutaneous pelvic fixation has evolved into a widely used, safe, and effective treatment option in the management of pelvic ring injuries. Proper preoperative and intraoperative radiographic evaluation of these injuries is critical to ensure safe placement of fixation of the pelvis. Traditional intraoperative views for posterior pelvic ring fixation include the pelvic inlet and outlet views. We propose that the intraoperative use of a hyperinlet view, which uses additional cranial tilt relative to the traditional inlet view, is helpful to better delineate the spinal canal and thereby better define the posterior limit of the osseous fixation pathway of the upper sacral segments. This study illustrates the use of this novel radiographic view and presents a patient cohort in which it was effectively used.

Preoperative CT simulation of iliosacral screws for treating unstable posterior pelvic ring injury

BACKGROUND

The percutaneous iliosacral screw is a common procedure for treating pelvic posterior ring instability. Traditional X-ray fluoroscopy screw placement has the advantages of decreased bleeding and trauma, but it also has some drawbacks, such as increased radiation exposure and screw dislocation. The purpose of this study was to establish a safe, effective, and quick approach for putting iliosacral screws for the treatment of unstable posterior pelvic ring damage utilizing simulated screws based on preoperative computed tomography (CT) planning.

METHODS

From February 2019 to June 2020, we retrospectively assessed 41 patients with posterior pelvic ring instability who were treated with percutaneous iliosacral screws in our institution, and randomly separated them into two groups: conventional surgery (n = 20) and preoperative planning (n = 21). Pelvic radiographs (anteroposterior, inlet, outlet), as well as normal CT scans of the pelvis, were all taken postoperatively to confirm the screw position. After that, the screw insertion time, the radiation exposure time, and the screw misplacement rate (as assessed by postoperative CT) were all examined. Screw position grading was evaluated by Smith grading.

RESULTS

In the conventional surgery group, 26 screws were inserted in 20 patients, with each screw insertion taking 23.15 ± 4.19 min and 1.02 ± 0.17 min to expose to radiation. Eight of the 26 screws were misplaced (30.8%). In the preoperative planning group, 24 screws were inserted in 21 patients, with each screw taking 19.57 ± 4.05 min to implant and 0.67 ± 0.09 min to expose to radiation. One of 24 screws was misplaced (4.2%). Screw insertion time, radiation exposure time, and screw dislocation rate were all significantly reduced when preoperative planning aided iliosacral screw placement (P < 0.05).

CONCLUSIONS

Preoperative CT simulation of iliosacral screws for placement planning, screw trajectory, and intraoperative screw placement is a safe way for reducing surgical time, radiation exposure, and ensuring accurate screw placement.