Durability and Failure Types of S2-Alar-Iliac Screws: An Analysis of 312 Consecutive Screws

Abstract BACKGROUND S2-alar-iliac (S2AI) screws improve stability across the lumbosacral junction in spinopelvic fixation procedures by crossing the cortical surfaces of the sacroiliac joint (SIJ), thereby increasing the biomechanical strength of the instrumentation. OBJECTIVE To investigate the durability and failure types of S2AI screws after spinopelvic reconstruction surgery. METHODS A single-center, single-surgeon consecutive series of patients who underwent spinopelvic fixation using bilateral S2AI screws with a ≥1-yr follow-up and at least 1 postoperative computed tomographic scan were retrospectively reviewed. Patient characteristics, radiographic parameters, operative data, clinical outcomes, and complications were analyzed. RESULTS In total, 312 S2AI screws in 156 patients were evaluated (mean follow-up, 26.1 mo; range 12-71 mo). There were no significant differences in screw diameter, length, or insertion angle between right-side and left-side screws. Visual analogue scale scores for back pain, ambulatory status, and Oswestry Disability Index scores significantly improved. A total of 10 patients (3.2%) experienced SIJ pain after S2AI screw installation. SIJ pain improved in 8 of them following SIJ block. In total, 7 screws (2.2%) showed partial periscrew lucency. Set screw dislodgement occurred in 7 screws (2.2%). Screw fracture occurred in 6 screws (1.9%): 5 neck fractures and 1 shaft fracture. A total of 5 patients (1.6%) underwent revision surgery for S2AI screw failure. Distal device (L4-pelvis region) breakage occurred in 5 patients. CONCLUSION The radiographic and clinical outcomes of S2AI screw fixation were acceptable. However, S2AI screw fixation has several drawbacks, including screw fracture and dislodgement of the set screw. SIJ irritation symptoms after S2AI screw fixation occurred with considerable frequency.

Download Full-text

Failure Types & Analysis In Cu Process Development of Design-Rule 0.18μm CPU

ISTFA 2001: Conference Proceedings from the 27th International Symposium for Testing and Failure Analysis ◽

10.31399/asm.cp.istfa2001p0115 ◽

2001 ◽

Author(s):

DongKwon Jeong ◽

JuHyeon Ahn ◽

SangIn Lee ◽

JooHyuk Chung ◽

ByungLyul Park ◽

...

Keyword(s):

Process Improvement ◽

Process Development ◽

Metal Corrosion ◽

Pass Rate ◽

Design Rule ◽

The Novel ◽

Corrosion Loss ◽

Barrier Metal ◽

Development State ◽

Failure Types

Abstract This paper presents the problems, the solutions, and the development state of the novel 0.18 μm Cu Metal Process through failure analysis of the Alpha CPU under development at Samsung Electronics. The presented problems include : “Via Bottom Lifting” induced by the Cu Via void, “Via Bottom dissociation” due to the IMD stress, “Via side dissociation” due to the poor formation of the Barrier Metal, “Via short/not-open failure” due to the IMD lifting, and Cu metal Corrosion/Loss. The analysis was carried out on the Via Contact Test Chain Patterns, using the “Electron (ION) Charge Up” method. After carefully analyzing each of the failure types, process improvement efforts followed. As a result, the pass rate of the via contact Rc was brought up from a mere 20% to 95%, and the device speed higher than 1.1 GHz was achieved, which surpasses the target speed of 1 GHz.

Download Full-text

Navigated iliac screw placement may reduce radiation and OR time in lumbopelvic fixation of unstable complex sacral fractures

European Journal of Orthopaedic Surgery & Traumatology ◽

10.1007/s00590-021-02892-7 ◽

2021 ◽

Author(s):

M. F. Hoffmann ◽

E. Yilmaz ◽

D. C. Norvel ◽

T. A. Schildhauer

Keyword(s):

Radiation Exposure ◽

Operative Time ◽

Pelvic Ring ◽

Screw Placement ◽

Fluoroscopy Time ◽

Complication Rates ◽

Lumbopelvic Fixation ◽

Navigation Group ◽

Iliac Screws ◽

Iliac Screw

Abstract Purpose Instability of the posterior pelvic ring may be stabilized by lumbopelvic fixation. The optimal osseous corridor for iliac screw placement from the posterior superior iliac spine to the anterior inferior iliac spine requires multiple ap- and lateral-views with additional obturator-outlet and -inlet views. The purpose of this study was to determine if navigated iliac screw placement for lumbopelvic fixation influences surgical time, fluoroscopy time, radiation exposure, and complication rates. Methods Bilateral lumbopelvic fixation was performed in 63 patients. Implants were inserted as previously described by Schildhauer. A passive optoelectronic navigation system with surface matching on L4 was utilized for navigated iliac screw placement. To compare groups, demographics were assessed. Operative time, fluoroscopic time, and radiation were delineated. Results Conventional fluoroscopic imaging for lumbopelvic fixation was performed in 32 patients and 31 patients underwent the procedure with navigated iliac screw placement. No differences were found between the groups regarding demographics, comorbidities, or additional surgical procedures. Utilization of navigation led to fluoroscopy time reduction of more than 50% (3.2 vs. 8.6 min.; p < 0.001) resulting in reduced radiation (2004.5 vs. 5130.8 Gy*cm2; p < 0.001). Operative time was reduced in the navigation group (176.7 vs. 227.4 min; p = 0.002) despite the necessity of additional surface referencing. Conclusion For iliac screws, identifying the correct entry point and angle of implantation requires detailed anatomic knowledge and multiple radiographic views. In our study, additional navigation reduced operative time and fluoroscopy time resulting in a significant reduction of radiation exposure for patients and OR personnel.

Download Full-text

Commentary: Failure Types and Related Factors of Spinopelvic Fixation After Long Construct Fusion for Adult Spinal Deformity

Neurosurgery ◽

10.1093/neuros/nyaa489 ◽

2020 ◽

Author(s):

Lee A Tan

Keyword(s):

Spinal Deformity ◽

Adult Spinal Deformity ◽

Related Factors ◽

Spinopelvic Fixation ◽

Failure Types

Download Full-text

Minimally Invasive Techniques for Iliac Bolt Placement: 2-Dimensional Operative Video

Operative Neurosurgery ◽

10.1093/ons/opab001 ◽

2021 ◽

Vol 20 (4) ◽

pp. E292-E292

Author(s):

Travis Hamilton ◽

Mohamed Macki ◽

Thomas M Zervos ◽

Victor Chang

Keyword(s):

Minimally Invasive ◽

Imaging System ◽

Pedicle Screws ◽

Vertical Axis ◽

Spinal Diseases ◽

Open Approach ◽

Sagittal Vertical Axis ◽

Pelvic Fixation ◽

Iliac Screws ◽

Invasive Techniques

Abstract As the popularity of minimally invasive surgery (MIS) continues to grow, novel techniques are needed to meet the demands of multisegment fixation for advanced spinal diseases. In one such example, iliac bolts are often required to anchor large fusion constructs, but MIS technical notes are missing from the literature. A 67-yr-old female presented with a symptomatic coronal deformity: preoperative pelvic incidence = 47°, pelvic tilt = 19°, and lumbar lordosis = 29°, sagittal vertical axis = +5.4 cm with 30° of scoliosis. The operative plan included T10-ilium fusion with transforaminal interbody grafts at L2-3, L3-4, L4-5, and L5-S1. The intraoperative video is of minimally invasive placement of iliac bolts using the O-Arm Surgical Imaging System (Medtronic®). The patient consented to the procedure. A mini-open exposure that remains above the fascial planes allows for multilevel instrumentation with appropriate decompression at the interbody segments. After the placement of the pedicle screws under image-guidance, the direction is turned to the minimally invasive iliac bolts. Following the trajectory described in the standard open approach,1 the posterior superior iliac spine (PSIS) is identified with the navigation probe, which will guide the Bovie cautery through the fascia. This opening assists in the trajectory of the navigated-awl tap toward the anterior superior iliac spine (ASIS). Next, 8.5 mm x 90 mm iliac screws were placed in the cannulated bone under navigation. After intraoperative image confirmation of screw placement, the contoured rods are threaded under the fascia. The setscrews lock the rod in position. MIS approaches obviate cross-linking the rods, rendering pelvic fixation more facile. This technique allows for minimal dissection of the posterior pelvic soft tissue while maintaining adequate fixation.

Download Full-text

Reconstruction after Subtotal Sacrectomy for Sacral Ewing’s Sarcoma Using Tibial Allograft Strut Grafting: A Case Report

Case Reports in Oncology ◽

10.1159/000513117 ◽

2021 ◽

pp. 296-302

Author(s):

Ryosuke Hirota ◽

Makoto Emori ◽

Yoshinori Terashima ◽

Kousuke Iba ◽

Noriyuki Iesato ◽

...

Keyword(s):

Surgical Treatment ◽

Ewing’S Sarcoma ◽

Mechanical Stability ◽

Ewing's Sarcoma ◽

Lumbar Vertebrae ◽

Iliac Screws ◽

Sacral Tumor ◽

Sacral Resection ◽

High Mechanical Stability ◽

Rectal Dysfunction

We present the case of a 15-year-old girl. Two months after becoming aware of pain, she was diagnosed with a sacral tumor and referred to our department. She was diagnosed with a sacral Ewing’s sarcoma; after chemotherapy, it was determined that the tumor could be resected, so surgical treatment was performed. The sacrum and ilium were partially resected at the lower end of S1, and the lumbar vertebrae and pelvis were fixed with a pedicle screw and two iliac screws on each side of L3, and the sacral resection was reconstructed with a tibial strut allograft. No tumor recurrence or metastasis has been observed 1 year postoperatively. She developed bladder and rectal dysfunction, but she remained independent in activities of daily living and her daily life was not limited. The bone fusion in the reconstructed area confirmed the lack of instrumentation looseness. Surgical treatment for sacral Ewing’s sarcoma was performed to cure the patient. We believe that the tibial allograft contributed to the patient’s ability to walk on her own due to its high mechanical stability. Postoperative bone healing was observed with the same material, suggesting that the tibial allograft is useful for similar procedures.

Download Full-text

From a reactive to a proactive safety approach. Analysis of medication errors in chemotherapy using general failure types

European Journal of Cancer Care ◽

10.1111/ecc.12348 ◽

2015 ◽

Vol 26 (1) ◽

pp. e12348 ◽

Cited By ~ 6

Author(s):

A. Fyhr ◽

S. Ternov ◽

Å. Ek

Keyword(s):

Medication Errors ◽

Failure Types ◽

Proactive Safety

Download Full-text

Progressive Failure Analysis in Open-Hole Tensile Composite Laminates of Airplane Stringers Based on Tests and Simulations

Applied Sciences ◽

10.3390/app11010185 ◽

2020 ◽

Vol 11 (1) ◽

pp. 185

Author(s):

Jian Shi ◽

Mingbo Tong ◽

Chuwei Zhou ◽

Congjie Ye ◽

Xindong Wang

Keyword(s):

Failure Analysis ◽

Composite Laminates ◽

Progressive Failure ◽

Tensile Load ◽

Fiber Failure ◽

Stress Criterion ◽

Progressive Failure Analysis ◽

Analysis Technique ◽

Open Hole ◽

Failure Types

The failure types and ultimate loads for eight carbon-epoxy laminate specimens with a central circular hole subjected to tensile load were tested experimentally and simulated using two different progressive failure analysis (PFA) methodologies. The first model used a lamina level modeling based on the Hashin criterion and the Camanho stiffness degradation theory to predict the damage of the fiber and matrix. The second model implemented a micromechanical analysis technique coined the generalized method of cells (GMC), where the 3D Tsai–Hill failure criterion was used to govern matrix failure, and the fiber failure was dictated by the maximum stress criterion. The progressive failure methodology was implemented using the UMAT subroutine within the ABAQUS/implicit solver. Results of load versus displacement and failure types from the two different models were compared against experimental data for the open hole laminates subjected to tensile displacement load. The results obtained from the numerical simulation and experiments showed good agreement. Failure paths and accurate damage contours for the tested specimens were also predicted.

Download Full-text