Computer assisted screw insertion into real 3D rapid prototyping pelvis models

Comparison of Three-Dimensional Navigation-Guided Percutaneous Iliosacral Screw and Minimally Invasive Percutaneous Plate for the Treatment of Zone II Unstable Sacral Fractures

OBJECTIVE

The percutaneous IS screws and the minimally invasive percutaneous plate are the most popular internal methods for Zone II unstable sacral fractures. However, the choice of fixation remains controversial for orthopaedic surgeons. The purpose of study was to evaluate and compare the clinical results of percutaneous iliosacral (IS) screw fixation under three-dimensional (3D) navigation and minimally invasive percutaneous plate fixation in the treatment of Zone II unstable sacral fractures.

METHODS

A retrospective study was performed, including 64 patients with Zone II unstable sacral fractures who underwent percutaneous IS screw fixation under 3D navigation (navigation group) and minimally invasive percutaneous plate fixation (plate group) from January 2011 and March 2021 in our department. The age, gender, fracture type, mechanism of injury, injury severity score (ISS), time from admission to operation, operative time, intraoperative blood loss, hospital stay, incision length, follow-up time, time to clinical healing, and complications were recorded and analyzed. Matta standard was used to assess fracture reduction outcomes. The Majeed function system assessed functional outcomes at the last follow-up.

RESULTS

The average follow-up time was (14.42 ± 1.57) months in the navigation group and (14.79 ± 1.37) months in the plate group. No statistical difference between the two groups in age, gender, fracture type, mechanism of injury, ISS, time from admission to operation, and time to clinical healing. However, significant differences were detected in operative time, intraoperative blood loss, hospital stay, and incision length (p < 0.001). According to Matta standard at 2 days postoperatively, the excellent and good rate was 91.42% in the navigation group, and it was 93.10% in the plate group. There was no significant difference between the two groups (p = 0.961). According to Majeed function system at the follow-up, the excellent and good rate was 97.14% in the navigation group, and 93.10% in the plate group. The difference between the two groups was not statistically significant (p = 0.748). There were no neurovascular injuries associated with this procedure. The incidence of complications was 44.82% (13/29) in the plate group, while 14.28% (5/35) in the navigation group (p = 0.007).

CONCLUSION

This study found that compared with minimally invasive percutaneous plate fixation, percutaneous IS screw fixation under 3D navigation is a suitable option for the treatment of Zone II unstable sacral fractures. This approach is characterized by its shorter operation time, less surgical trauma, less bleeding, less hospital time, and fewer complications.

Comparison of Efficacy between 3D Navigation-Assisted Percutaneous Iliosacral Screw and Minimally Invasive Reconstruction Plate in Treating Sacroiliac Complex Injury

The clinical efficacy was compared between 3D navigation-assisted percutaneous iliosacral screw (3DPS) and minimally invasive reconstruction plate (MIRP) in treating sacroiliac complex injury and the surgical procedures of 3DPS were introduced. A retrospective analysis was performed on 49 patients with sacroiliac complex injury from March 2013 to May 2017. Twenty-one cases were treated by 3DPS, and 28 cases by MIRP. Intraoperative indexes as operative time, blood loss, incision length, length of hospital stay and postoperative complications were respectively documented. Quality of reduction was postoperatively evaluated by Matta radiological criteria, and clinical effect was assessed by Majeed scoring criteria at the last follow-up. Operative time and hospital stay were significantly shortened, and blood loss, and incision length were significantly reduced in 3DPS group as compared with those in MIRP group (P<0.05). No statistically significant difference was found between 3DPS group and MIRP group in the assessment of reduction and function (P>0.05). It was concluded that both 3DPS and MIRP can effectively treat the sacroiliac complex injury, and 3DPS can provide an accurate, safe and minimally invasive fixation with shorter operative time and hospital stay.

Radiological Society of North America (RSNA) 3D printing Special Interest Group (SIG): guidelines for medical 3D printing and appropriateness for clinical scenarios

Medical three-dimensional (3D) printing has expanded dramatically over the past three decades with growth in both facility adoption and the variety of medical applications. Consideration for each step required to create accurate 3D printed models from medical imaging data impacts patient care and management. In this paper, a writing group representing the Radiological Society of North America Special Interest Group on 3D Printing (SIG) provides recommendations that have been vetted and voted on by the SIG active membership. This body of work includes appropriate clinical use of anatomic models 3D printed for diagnostic use in the care of patients with specific medical conditions. The recommendations provide guidance for approaches and tools in medical 3D printing, from image acquisition, segmentation of the desired anatomy intended for 3D printing, creation of a 3D-printable model, and post-processing of 3D printed anatomic models for patient care.

Biomechanics of L5/S1 in Long Thoracolumbosacral Constructs: A Cadaveric Study

STUDY DESIGN

In vitro cadaveric biomechanical study.

OBJECTIVES

Despite numerous techniques employed to establish solid lumbosacral fixation, there are little biomechanical data correlating fixation methods at L5/S1 to thoracolumbosacral (TLS) construct length. We aimed to determine the optimal construct with the hypothesis that under physiological loads, lumbosacral constructs can be stabilized by L5/S1 anterior lumbar interbody fusion (ALIF) alone, without iliac screw fixation (ISF), and that TLS constructs would require ISF, with or without ALIF.

METHODS

By using a robot capable of motion in 6 axes, force-moment sensor, motion-tracking camera system and software, we simulated the spinal loading effects in flexion-extension, axial rotation, and lateral bending, and compared torques in different construct groups of T4-S1, T10-S1, and L2-S1. By conducting multidirectional flexibility testing we assessed the effects of constructs of various lengths on the L5/S1 segment.

RESULTS

L2-S1 constructs may be equivalently stabilized by L5/S1 ALIF alone without ISF. Longer TLS constructs exerted increasing motion at L5/S1, exhibiting trends in favor of ISF when extending to T10 and statistically improved fixation when extending to T4. Lastly, TLS constructs with ISF exhibited a statistically significant reduction in L5-S1 range of motion from the addition of ALIF when extending to T4-pelvis but not T10-pelvis.

CONCLUSIONS

We found that ALIF alone may sufficiently support the L2-S1 construct, reducing L5/S1 range of motion and transmitting loads instead to the sacropelvis. Furthermore, ALIF was found to add significant stability to the T4-pelvis construct when added to ISF. This difference was not significant for the T10-pelvis construct.

Three-dimensional printing in orthopaedic surgery: review of current and future applications

Three-dimensional (3D) printing is a rapidly evolving technology with the potential for significant contributions to surgical practice. There are many current applications for 3D printing technology with future applications being explored. This technology has applications in preoperative planning, education, custom manufacturing (implants, prosthetics and surgical guides) and exciting potential for biological applications. This article reviews the current and future applications of 3D technology in orthopaedic surgery.

Comparative use of the computer-aided angiography and rapid prototyping technology versus conventional imaging in the management of the Tile C pelvic fractures

INTRODUCTION

Computed tomography (CT) scan with three-dimensional (3D) reconstruction has been used to evaluate complex fractures in pre-operative planning. In this study, rapid prototyping of a life-size model based on 3D reconstructions including bone and vessel was applied to evaluate the feasibility and prospect of these new technologies in surgical therapy of Tile C pelvic fractures by observing intra- and perioperative outcomes.

MATERIALS AND METHODS

The authors conducted a retrospective study on a group of 157 consecutive patients with Tile C pelvic fractures. Seventy-six patients were treated with conventional pre-operative preparation (A group) and 81 patients were treated with the help of computer-aided angiography and rapid prototyping technology (B group). Assessment of the two groups considered the following perioperative parameters: length of surgical procedure, intra-operative complications, intra- and postoperative blood loss, postoperative pain, postoperative nausea and vomiting (PONV), length of stay, and type of discharge.

RESULTS

The two groups were homogeneous when compared in relation to mean age, sex, body weight, injury severity score, associated injuries and pelvic fracture severity score. Group B was performed in less time (105 ± 19 minutes vs. 122 ± 23 minutes) and blood loss (31.0 ± 8.2 g/L vs. 36.2 ± 7.4 g/L) compared with group A. Patients in group B experienced less pain (2.5 ± 2.3 NRS score vs. 2.8 ± 2.0 NRS score), and PONV affected only 8 % versus 10 % of cases. Times to discharge were shorter (7.8 ± 2.0 days vs. 10.2 ± 3.1 days) in group B, and most of patients were discharged to home.

CONCLUSIONS

In our study, patients of Tile C pelvic fractures treated with computer-aided angiography and rapid prototyping technology had a better perioperative outcome than patients treated with conventional pre-operative preparation. Further studies are necessary to investigate the advantages in terms of clinical results in the short and long run.

Accuracy of Computer Assisted Percutaneous Placement of Hiosacral Screws: A Cadaveric Study

OBJECTIVE

To determine the accuracy of computer-assisted fluoronavigation for percutaneous iliosacral screw placement.

MATERIALS AND METHODS

A fluoronavigation system (Stryker Navigation System, Stryker Leibinger, Kalamazoo, MI) was used to guide the placement of four iliosacral screws into the S-1 bodies of each of five cadaveric pelvic specimens with intact soft tissues. Accuracy of screw placement was verified by radiographs, CT scans, and direct dissection.

RESULTS

All 20 screws were placed accurately without complications. Nineteen screws were completely contained within the osseous "safe zone." On direct dissection, one screw was noted to have penetrated the S-1 foramina by 3 mm without impingement on the nerve root. This was not detected on radiograph or CT scan.

CONCLUSION

The results of this study support the safety and accuracy of computer-assisted fluoronavigation for iliosacral screw placement. The advantages include decreased fluoroscopic time, real-time simultaneous visualization of all three views (inlet, outlet, and lateral), and increased accuracy of placement. Clinical study is warranted.

Rapid prototyping technology for surgeries of the pediatric spine and pelvis: benefits analysis

BACKGROUND

The benefits provided by rapid prototyping (RP) of patient anomalies in complex surgeries of the pediatric spine and pelvis were elucidated and characterized.

METHODS

Surgeons involved in the study were solicited from the Texas Scottish Rite Hospital for Children and the network of Shriners Hospitals for Children throughout the United States. Rapid prototyping models were created at Boise State University through a federally funded Economic Development Agency grant (Economic Development Agency Project Number 07-79-05312). Rapid prototyping models and detailed survey forms were supplied to lead surgeons for 13 cases of multiplane spinal or pelvic deformity.

RESULTS

Results indicated that surgeons found RP models useful for preoperative planning, reference during surgery, communication with patients, and for increasing the safety of the procedure. Rapid prototyping models also led to a reduction in operating time in 4 of the 5 surgeries to correct congenital scoliosis/kyphosis.

CONCLUSIONS

Surgeons can expect properly constructed RP models to provide significant benefits for complex surgeries of the pediatric spine and pelvis in the areas of preoperative planning, intrasurgical navigation, and communication with patients. A reduction in operating time may also be expected for cases of congenital scoliosis/kyphosis.

CLINICAL RELEVANCE

This study was a type II prospective observational study of physicians' perceptions of the use of RP models to assist with surgical cases. Results provided by this study suggest expected benefits from application of RP in surgeries of the pediatric spine and pelvis with complex deformities.

Comparison of Computer-Assisted Surgery with Conventional Technique for the Treatment of Axial Distal Phalanx Fractures in Horses: An In Vitro Study

OBJECTIVES

To compare the precision obtained with computer-assisted screw insertion for treatment of mid-sagittal articular fractures of the distal phalanx (P3) with results achieved with a conventional technique.

STUDY DESIGN

In vitro experimental study.

SAMPLE POPULATION

Thirty-two cadaveric equine limbs.

METHODS

Four groups of 8 limbs were studied. Either 1 or 2 screws were inserted perpendicular to an imaginary axial fracture of P3 using computer-assisted surgery (CAS) or conventional technique. Screw insertion time, predetermined screw length, inserted screw length, fit of the screw, and errors in placement were recorded.

RESULTS

CAS technique took 15-20 minutes longer but resulted in greater precision of screw length and placement compared with the conventional technique.

CONCLUSION

Improved precision in screw insertion with CAS makes insertion of 2 screws possible for repair of mid-sagittal P3 fractures.

CLINICAL RELEVANCE

CAS although expensive improves precision in screw insertion into P3 and consequently should yield improved clinical outcome.