Percutaneous Sacroiliac Screw Fixation Research Articles

Intraoperative fluoroscopy in percutaneous sacroiliac screw fixation based on anatomic measurement and digital reconstructed CT data

Objective To explore the intraoperative fluoroscopy in percutaneous sacroiliac screw fixation based on anatomic measurement and digital reconstructed CT data. Methods The CT data of the pelvis at prostration were collected for 3D reconstruction of the pelvic models from 30 patients with injury to the pelvis or acetabulum.Then the anatomical boundaries of the safe zone of sacroiliac screw insertion were marked on the 3D models,including the upper,front and back cortex boundaries of S1 vertebra,the front and bottom cortex boundaries of sacral foramen area,and the sacral alar slope. The angles between these anatomical boundaries and the pelvic baseline were measured on the sagittal plane.The digital reconstructed radiology (DRR) was applied to form the inlet,outlet and lateral images of fluoroscopy.The standard protocol to acquire accurate intraoperative images was analyzed by characterization of important anatomic landmarks.Results The angles between the upper,front and back cortex boundaries of S1 vertebra and the baseline (αl,α2,α3) were respectively 37.7°± 8.6°(from 23.2°to 50.8°),22.9° ± 6.7° (from 13.1° to 32.0°),41.9°± 6.8° (from 33.0°to 54.8°).The angles between the front and bottom cortex boundaries of sacral foramen area and the baseline (α4,α5) were 37.0°± 12.0° (from 19.9° to 63.1°) and 38.8°± 8.0° (from 25.7°to 54.6°).The angle between the alar slope and the baseline (α6) was 82.4°± 13.0°(from 70.3°to117.3°).The characteristic manifestations of important anatomic landmarks were observed in the simulated fluoroscopy images. Conclusions It is recommended that the projecting angles in the inlet and outlet views should be decided according to the specific data of each patient.Because the alar slope can not be clearly identified in the outlet view due to its large inclination,the position of screw insertion should be verified in the lateral view to prevent the screw from penetrating the slope to hurt the L5 nerve and iliac vessels. Key words: Bone nails; Pelvis; Tomography, X-ray computed; Image processing, computer-assisted; Sacroiliac joint

Minimally Invasive Sacroiliac Fixation in Oncologic Patients With Sacral Insufficiency Fractures Using a Fluoroscopy-based Navigation System

Surgical technique article with retrospective case series. Sacral insufficiency fractures are commonly encountered in oncologic patients and constitute a cause for persistent lower back and pelvic pain. The aim of this study is to describe the modified technique of navigated percutaneous sacroiliac (SI) fixation using multiple long screws per level that cross both SI joints and engage bilateral iliac bones; furthermore to evaluate its safety and efficacy in oncologic patients with sacral insufficiency fractures. Six oncologic patients (3 male, 3 female, mean age: 58.8 y) with sacral insufficiency fractures who had undergone additional radiation therapy were operated with navigated percutaneous fixation. Two patients had failed preoperative sacroplasty and 1 had failed SI pinning. Eighteen SI screws were placed (15 at S1 level and 3 at S2). In the majority of cases the screws were long enough to engage bilateral ilium and sacrum. Additionally, 1 patient underwent percutaneous iliolumbar instrumentation and in 4 patients we performed concomitant sacroplasty or polymethylmethacrylate screw augmentation. The patients were followed for 18.8 months in average (range: 12-30 mo). Outcome was assessed using the Karnofsky Performance Status score (KPS), pain scale (0-10) and detailed neurologic examination. In 1 case, a revision of a screw was required due to radiculopathy. There was no perioperative morbidity or mortality. No hardware failure was encountered. There was significant improvement in KPS (P=0.04) and pain levels (P=0.02). These preliminary data suggest that navigated percutaneous SI screw fixation is a safe and effective intervention in terms of pain control and performance status improvement in oncologic patients with sacral insufficiency fractures. For optimal fixation, multiple long screws that engage both iliac bones may be inserted through the S1 level in a safe manner. The technique may be combined with sacroplasty or closed posterior instrumentation to augment the screw fixation. Further investigation is needed to compare this technique with other treatment modalities.

Minimal-invasive Stabilisierung einer bilateralen Sakrumfraktur mit lumbopelviner Dissoziation

This case report describes our technique of percutaneous sacroiliac screw fixation of a bilateral sacral fracture with spinopelvic dissociation. It is based on the description of an iliosacroiliac bony corridor delimited by the following landmarks: the sacral ala in a superior-anterior direction, the first sacral foramen on both sides in an inferior-posterior direction, and the sacral channel posteriorly. The described operating method, which uses a 6.5-mm parallel drill sleeve, allows the safe and strictly transversal positioning of a 7.3-mm screw on each side with the threads interlocking. It provides a separate and fracture-adapted compression of the screws. The interlocking SI screw threads increase the pull-out strength. Operating time and radiation dose can be reduced significantly by this method.

Reduced Invasive Techniques in Pelvic Ring and Acetabular Fractures

Summary: Although reduced invasive techniques are already used in many fields of trauma surgery, there are only a few applications presently available for pelvic and acetabular surgery. This is the result of the irregular anatomy of the pelvic bones and the enclosed organs, vascular and neural structures. During the past 20 years, standardized techniques for reduction and stabilization of pelvic and acetabular fractures have been developed, which has also led to a lower morbidity. However, the tremendous advances in visualization, mainly based on computed tomography (CT) and 3-D CT which made a far better analysis of the fracture pattern possible, could not be transferred directly into surgery. For specific indications, there are also reduced invasive techniques available. Percutaneous sacroiliac screw fixation is done with control by fluoroscope or as modality-based navigation by CT. The lower invasiveness must be weighed against the specific risks with high rates of screw malplacement, especially for beginners, or injury to the adjacent neural roots. However, also controlled by CT, the reduction of displaced fractures remains a problem. For acetabular fractures, the extended Pfannenstiel approach, which is indicated for fractures with involvement of both columns, provides an excellent exposition of the acetabulum from a medial location. This approach is indicated especially for the elderly, because of the frequently central displacement of the femoral head. Also, cerclage wiring of certain acetabular fractures can be used for indirect reduction and sometimes definite stabilization of acetabular fractures. Recent developments in the fields of computer-assisted and robotic surgery made it possible to use this promising technique also in the fields of trauma and orthopaedic surgery. The applications that are used already support certain steps of the operation. Further developments could lead to the use for the complete operation, including visualization and guiding of reduction..