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Bryson XM, Pham NS, Hollyer I, Hu S, Rinsky LA, Vorhies JS. 3D CT modeling demonstrates the anatomic feasibility of S1AI screw trajectory for spinopelvic fixation in neuromuscular scoliosis. Spine Deform 2024:10.1007/s43390-024-00840-z. [PMID: 38733488 DOI: 10.1007/s43390-024-00840-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Accepted: 02/07/2024] [Indexed: 05/13/2024]
Abstract
PURPOSE In patients with neuromuscular scoliosis undergoing posterior spinal fusion, the S2 alar iliac (S2AI) screw trajectory is a safe and effective method of lumbopelvic fixation but can lead to implant prominence. Here we use 3D CT modeling to demonstrate the anatomic feasibility of the S1 alar iliac screw (S1AI) compared to the S2AI trajectory in patients with neuromuscular scoliosis. METHODS This retrospective study used CT scans of 14 patients with spinal deformity to create 3D spinal reconstructions and model the insertional anatomy, max length, screw diameter, and potential for implant prominence between 28 S2AI and 28 S1AI screw trajectories. RESULTS Patients had a mean age of 14.42 (range 8-21), coronal cobb angle of 85° (range 54-141), and pelvic obliquity of 28° (range 4-51). The maximum length and diameter of both screw trajectories were similar. S1AI screws were, on average, 6.3 ± 5 mm less prominent than S2AI screws relative to the iliac crests. S2AI screws were feasible in all patients, while in two patients, posterior elements of the lumbar spine would interfere with S1AI screw insertion. CONCLUSION In this cohort of patients with neuromuscular scoliosis, we demonstrate that the S1AI trajectory offers comparable screw length and diameter to an S2AI screw with less implant prominence. An S1AI screw, however, may not be feasible in some patients due to interference from the posterior elements of the lumbar spine.
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Affiliation(s)
- Xochitl M Bryson
- Department of Orthopaedic Surgery, Stanford University School of Medicine, 453 Quarry Rd, 3rd Floor, MC 5658, Palo Alto, CA, USA
| | - Nicole S Pham
- Department of Orthopaedic Surgery, Stanford University School of Medicine, 453 Quarry Rd, 3rd Floor, MC 5658, Palo Alto, CA, USA
| | - Ian Hollyer
- Department of Orthopaedic Surgery, Stanford University School of Medicine, 453 Quarry Rd, 3rd Floor, MC 5658, Palo Alto, CA, USA
| | - Serena Hu
- Department of Orthopaedic Surgery, Stanford University School of Medicine, 453 Quarry Rd, 3rd Floor, MC 5658, Palo Alto, CA, USA
| | - Lawrence A Rinsky
- Department of Orthopaedic Surgery, Stanford University School of Medicine, 453 Quarry Rd, 3rd Floor, MC 5658, Palo Alto, CA, USA
| | - John S Vorhies
- Department of Orthopaedic Surgery, Stanford University School of Medicine, 453 Quarry Rd, 3rd Floor, MC 5658, Palo Alto, CA, USA.
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Rahmani R, Stegelmann SD, Andreshak T. S2 alar-iliac screws are superior to traditional iliac screws for spinopelvic fixation in adult spinal deformity: a systematic review and meta-analysis. Spine Deform 2024; 12:829-842. [PMID: 38427156 DOI: 10.1007/s43390-024-00834-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Accepted: 01/20/2024] [Indexed: 03/02/2024]
Abstract
PURPOSE Spinopelvic fixation (SPF) using traditional iliac screws has provided biomechanical advantages compared to previous constructs, but common complications include screw prominence and wound complications. The newer S2 alar-iliac (S2AI) screw may provide a lower profile option with lower rates of complications and revisions for adult spinal deformity (ASD). The purpose of this study was to compare rates of complications and revision following SPF between S2AI and traditional iliac screws in patients with ASD. METHODS A PRISMA-compliant systematic literature review was conducted using Cochrane, Embase, and PubMed. Included studies reported primary data on adult patients undergoing S2AI screw fixation or traditional IS fixation for ASD. Primary outcomes of interest were rates of revision and complications, which included screw failure (fracture and loosening), symptomatic screw prominence, wound complications (dehiscence and infection), and L5-S1 pseudarthrosis. RESULTS Fifteen retrospective studies with a total of 1502 patients (iliac screws: 889 [59.2%]; S2AI screws: 613 [40.8%]) were included. Pooled analysis indicated that iliac screws had significantly higher odds of revision (17.1% vs 9.1%, OR = 2.45 [1.25-4.77]), symptomatic screw prominence (9.9% vs 2.2%, OR = 6.26 [2.75-14.27]), and wound complications (20.1% vs 4.4%, OR = 5.94 [1.55-22.79]). S2AI screws also led to a larger preoperative to postoperative decrease in pain (SMD = - 0.26, 95% CI = -0.50, - 0.011). CONCLUSION The findings from this review demonstrate higher rates of revision, symptomatic screw prominence, and wound complications with traditional iliac screws. Current data supports the use of S2AI screws specifically for ASD. PROSPERO ID CRD42022336515. LEVEL OF EVIDENCE III.
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Affiliation(s)
- Roman Rahmani
- Mercy Health St. Vincent Medical Center, Toledo, OH, USA
| | - Samuel D Stegelmann
- HCA Medical City Healthcare UNT-TCU GME (Denton), 3535 S Interstate 35, Denton, TX, 76210, USA.
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Cho ST, Lee DH, Cho JH, Park S, Kim JH, Lee MY, Yoon SJ, Hwang CJ. Connecting the S2 alar-iliac screw head to the satellite rod for surgical correction of degenerative sagittal imbalance. Eur Spine J 2024:10.1007/s00586-023-08106-4. [PMID: 38195929 DOI: 10.1007/s00586-023-08106-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Revised: 11/05/2023] [Accepted: 12/15/2023] [Indexed: 01/11/2024]
Abstract
PURPOSE The S2AI screw technique has several advantages over the conventional iliac screw fixation technique. However, connecting the S2AI screw head to the main rod is difficult due to its medial entry point. We introduce a new technique for connecting the S2AI screw head to a satellite rod and compare it with the conventional method of connecting the S2AI screw to the main rod. METHODS Seventy-four patients who underwent S2AI fixation for degenerative sagittal imbalance and were followed up for ≥ 2 years were included. All the patients underwent long fusion from T9 or T10 to the pelvis. The S2AI screw head was connected to the satellite rod (SS group) in 43 patients and the main rod (SM group) in 31 patients. In the SS group, the satellite rod was placed medial to the main rod and connected by the S2AI screw and domino connectors. In the SM group, the main rod was connected directly to the S2AI screw head and supported by accessory rods. Radiographic and clinical outcomes were evaluated in both groups. RESULTS There were no significant differences in postoperative complications, including proximal junctional failure, proximal junctional kyphosis, rod breakage, screw loosening, wound problems, and infection between the two groups. Furthermore, the correction power of sagittal deformity and clinical results in the SS group were comparable to those in the SM group. CONCLUSION Connecting the S2AI screw to the satellite rod is a convenient method comparable to the conventional S2AI connection method in terms of radiological and clinical outcomes.
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Affiliation(s)
- Sung Tan Cho
- Department of Orthopedic Surgery, Ilsan Paik Hospital, Inje University, 170, Juhwa-ro, Ilsangeo-gu, Goyang-si, Gyeonggi-do, Republic of Korea
| | - Dong-Ho Lee
- Department of Orthopedic Surgery, Asan Medical Center, University of Ulsan College of Medicine, 43, Olymipic-ro, Songpa-gu, Seoul, Republic of Korea
| | - Jae Hwan Cho
- Department of Orthopedic Surgery, Asan Medical Center, University of Ulsan College of Medicine, 43, Olymipic-ro, Songpa-gu, Seoul, Republic of Korea
| | - Sehan Park
- Department of Orthopedic Surgery, Asan Medical Center, University of Ulsan College of Medicine, 43, Olymipic-ro, Songpa-gu, Seoul, Republic of Korea
| | - Jin Hwan Kim
- Department of Orthopedic Surgery, Ilsan Paik Hospital, Inje University, 170, Juhwa-ro, Ilsangeo-gu, Goyang-si, Gyeonggi-do, Republic of Korea
| | - Mi Young Lee
- Department of Orthopedic Surgery, Asan Medical Center, University of Ulsan College of Medicine, 43, Olymipic-ro, Songpa-gu, Seoul, Republic of Korea
| | - So Jeong Yoon
- Department of Orthopedic Surgery, Asan Medical Center, University of Ulsan College of Medicine, 43, Olymipic-ro, Songpa-gu, Seoul, Republic of Korea
| | - Chang Ju Hwang
- Department of Orthopedic Surgery, Asan Medical Center, University of Ulsan College of Medicine, 43, Olymipic-ro, Songpa-gu, Seoul, Republic of Korea.
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Zhao Y, Ma Y, Wang Q, Luo H, Liu J, Lu S. Digital anatomical study and clinical application of the ideal S2 alar-lliac screw trajectory. BMC Surg 2023; 23:301. [PMID: 37794394 PMCID: PMC10552375 DOI: 10.1186/s12893-023-02167-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Accepted: 08/25/2023] [Indexed: 10/06/2023] Open
Abstract
BACKGROUND To investigate the ideal trajectory for the S2AI screw and to clinically validate its safety feasibility. METHODS The 3D model was reconstructed from CT data of the pelvis of 30 selected adults, and the 3D coordinate system was established with the first sacral superior endplate as the horizontal plane. A set of cutting planes was made at 3 mm intervals in the coronal plane, and the cross-sectional internal tangent circles were divided in the target area. Using the linear fitting function, the axis of 90 mm length was calculated by the least squares method for each inner tangent circle center. The diameter of the axis is gradually increased until the first contact with the cortex, and the cylindrical model is the ideal screw trajectory. The intersection of the axis and the dorsal cortex is the screw placement point, which is located by Horizon Distance (HD) and Vertical Distance (VD); the diameter of the screw trajectory (d) is the diameter of the cylindrical model; the direction of the screw trajectory is determined by Sagittal Angle (SA) and Transverse Angle (TA). The screw trajectory orientation is determined by Sagittal Angle (SA) and Transverse Angle (TA). Based on the ideal screw trajectory, the 3D printed surgical guide and freehand techniques were used to verify its safety feasibility, respectively. RESULTS The screw placement points [HD (4.7 ± 1.0) mm, VD (19.7 ± 1.9) mm], screw placement directions [SA (31.3°±2.3°), TA (42.4°±2.3°)], and screw dimensions for the ideal screw trajectory of the S2AI were combined for analysis. (L is 90 mm, d is 13.2 ± 1.4 mm). The S2AI screw superiority rate [96.6% (56/58)] and reasonable rate [100%] were higher in the guide group than in the freehand group [90.0% (63/70), 97.1% (68/70)], but the differences were not statistically significant (P > 0.05). Although screws invaded the cortex in both groups, there were no associated adverse events in either group. CONCLUSION The S2AI screw-based ideal trajectory placement is a safe, feasible and accurate method of screw placement.
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Affiliation(s)
- Yonghui Zhao
- Department of Orthopedics, The First People's Hospital of Yunnan Province, The Affiliated Hospital of Kunming University of Science and Technology, 157 Jinbi Road, Kunming, Xishan District, China
| | - Yulong Ma
- Department of Orthopedics, The First People's Hospital of Yunnan Province, The Affiliated Hospital of Kunming University of Science and Technology, 157 Jinbi Road, Kunming, Xishan District, China
| | - Qiyang Wang
- Department of Orthopedics, The First People's Hospital of Yunnan Province, The Affiliated Hospital of Kunming University of Science and Technology, 157 Jinbi Road, Kunming, Xishan District, China
| | - Haotian Luo
- Department of Orthopedics, The First People's Hospital of Yunnan Province, The Affiliated Hospital of Kunming University of Science and Technology, 157 Jinbi Road, Kunming, Xishan District, China
| | - Jie Liu
- Department of Orthopedics, The First People's Hospital of Yunnan Province, The Affiliated Hospital of Kunming University of Science and Technology, 157 Jinbi Road, Kunming, Xishan District, China.
| | - Sheng Lu
- Department of Orthopedics, The First People's Hospital of Yunnan Province, The Affiliated Hospital of Kunming University of Science and Technology, 157 Jinbi Road, Kunming, Xishan District, China.
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Habib A, Muthiah N, Alattar A, Hoppe M, Agarwal N, Alan N, Hamilton DK, Ozpinar A. Direct Iliac Screw vs Sacral-2-Alar-Iliac Screws Technique for Sacropelvic Fixation: Technical Nuances and a Review of the Literature. Int J Spine Surg 2023; 17:511-519. [PMID: 37055178 PMCID: PMC10478702 DOI: 10.14444/8449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/15/2023] Open
Abstract
Sacropelvic (SP) fixation is the immobilization of the sacroiliac joint to attain lumbosacral fusion and prevent distal spinal junctional failure. SP fixation is indicated in numerous spinal conditions (eg, scoliosis, multilevel spondylolisthesis, spinal/sacral trauma, tumors, or infections). Many SP fixation techniques have been described in the literature. Currently, the most used surgical techniques for SP fixation are direct iliac screws and sacral-2-alar-iliac screws. There is currently no consensus in the literature on which technique carries more favorable clinical outcomes. In this review, we aim to assess the available data on each technique and discuss their respective advantages and disadvantages. We will also present our experience with a modification of direct iliac screws using a subcrestal approach and outline the future prospects of SP fixation.
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Affiliation(s)
- Ahmed Habib
- Department of Neurosurgery, University of Pittsburgh Medical Center, Pittsburgh, USA
- Hillman Cancer Center, University of Pittsburgh Medical Center, Pittsburgh, USA
| | - Nallammai Muthiah
- Department of Neurosurgery, University of Pittsburgh Medical Center, Pittsburgh, USA
| | - Ali Alattar
- Department of Neurosurgery, University of Pittsburgh Medical Center, Pittsburgh, USA
| | - Meagan Hoppe
- Hillman Cancer Center, University of Pittsburgh Medical Center, Pittsburgh, USA
| | - Nitin Agarwal
- Department of Neurosurgery, University of Pittsburgh Medical Center, Pittsburgh, USA
| | - Nima Alan
- Department of Neurosurgery, University of Pittsburgh Medical Center, Pittsburgh, USA
| | - David Kojo Hamilton
- Department of Neurosurgery, University of Pittsburgh Medical Center, Pittsburgh, USA
| | - Alp Ozpinar
- Department of Neurosurgery, University of Pittsburgh Medical Center, Pittsburgh, USA
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6
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Martin CT, Holton KJ, Elder BD, Fogelson JL, Mikula AL, Kleck CJ, Calabrese D, Burger EL, Ou-Yang D, Patel VV, Kim HJ, Lovecchio F, Hu SS, Wood KB, Harper R, Yoon ST, Ananthakrishnan D, Michael KW, Schell AJ, Lieberman IH, Kisinde S, DeWald CJ, Nolte MT, Colman MW, Phillips FM, Gelb DE, Bruckner J, Ross LB, Johnson JP, Kim TT, Anand N, Cheng JS, Plummer Z, Park P, Oppenlander ME, Sembrano JN, Jones KE, Polly DW. Catastrophic acute failure of pelvic fixation in adult spinal deformity requiring revision surgery: a multicenter review of incidence, failure mechanisms, and risk factors. J Neurosurg Spine 2023; 38:98-106. [PMID: 36057123 DOI: 10.3171/2022.6.spine211559] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 06/17/2022] [Indexed: 01/04/2023]
Abstract
OBJECTIVE There are few prior reports of acute pelvic instrumentation failure in spinal deformity surgery. The objective of this study was to determine if a previously identified mechanism and rate of pelvic fixation failure were present across multiple institutions, and to determine risk factors for these types of failures. METHODS Thirteen academic medical centers performed a retrospective review of 18 months of consecutive adult spinal fusions extending 3 or more levels, which included new pelvic screws at the time of surgery. Acute pelvic fixation failure was defined as occurring within 6 months of the index surgery and requiring surgical revision. RESULTS Failure occurred in 37 (5%) of 779 cases and consisted of either slippage of the rods or displacement of the set screws from the screw tulip head (17 cases), screw shaft fracture (9 cases), screw loosening (9 cases), and/or resultant kyphotic fracture of the sacrum (6 cases). Revision strategies involved new pelvic fixation and/or multiple rod constructs. Six patients (16%) who underwent revision with fewer than 4 rods to the pelvis sustained a second acute failure, but no secondary failures occurred when at least 4 rods were used. In the univariate analysis, the magnitude of surgical correction was higher in the failure cohort (higher preoperative T1-pelvic angle [T1PA], presence of a 3-column osteotomy; p < 0.05). Uncorrected postoperative deformity increased failure risk (pelvic incidence-lumbar lordosis mismatch > 10°, higher postoperative T1PA; p < 0.05). Use of pelvic screws less than 8.5 mm in diameter also increased the likelihood of failure (p < 0.05). In the multivariate analysis, a larger preoperative global deformity as measured by T1PA was associated with failure, male patients were more likely to experience failure than female patients, and there was a strong association with implant manufacturer (p < 0.05). Anterior column support with an L5-S1 interbody fusion was protective against failure (p < 0.05). CONCLUSIONS Acute catastrophic failures involved large-magnitude surgical corrections and likely resulted from high mechanical strain on the pelvic instrumentation. Patients with large corrections may benefit from anterior structural support placed at the most caudal motion segment and multiple rods connecting to more than 2 pelvic fixation points. If failure occurs, salvage with a minimum of 4 rods and 4 pelvic fixation points can be successful.
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Affiliation(s)
| | - Kenneth J Holton
- 1Department of Orthopaedic Surgery, University of Minnesota, Minneapolis
| | - Benjamin D Elder
- 2Department of Neurologic Surgery, Mayo Clinic, Rochester, Minnesota
| | - Jeremy L Fogelson
- 2Department of Neurologic Surgery, Mayo Clinic, Rochester, Minnesota
| | - Anthony L Mikula
- 2Department of Neurologic Surgery, Mayo Clinic, Rochester, Minnesota
| | - Christopher J Kleck
- 3Department of Orthopedics, University of Colorado, School of Medicine, Aurora, Colorado
| | - David Calabrese
- 3Department of Orthopedics, University of Colorado, School of Medicine, Aurora, Colorado
| | - Evalina L Burger
- 3Department of Orthopedics, University of Colorado, School of Medicine, Aurora, Colorado
| | - David Ou-Yang
- 3Department of Orthopedics, University of Colorado, School of Medicine, Aurora, Colorado
| | - Vikas V Patel
- 3Department of Orthopedics, University of Colorado, School of Medicine, Aurora, Colorado
| | - Han Jo Kim
- 4Department of Orthopaedic Surgery, Hospital for Special Surgery, New York, New York
| | - Francis Lovecchio
- 4Department of Orthopaedic Surgery, Hospital for Special Surgery, New York, New York
| | - Serena S Hu
- 5Department of Orthopaedic Surgery, Stanford University, Stanford, California
| | - Kirkham B Wood
- 5Department of Orthopaedic Surgery, Stanford University, Stanford, California
| | - Robert Harper
- 5Department of Orthopaedic Surgery, Stanford University, Stanford, California
| | - S Tim Yoon
- 6Department of Orthopaedics, Emory University, Atlanta, Georgia
| | | | - Keith W Michael
- 6Department of Orthopaedics, Emory University, Atlanta, Georgia
| | - Adam J Schell
- 6Department of Orthopaedics, Emory University, Atlanta, Georgia
| | | | - Stanley Kisinde
- 7Scoliosis and Spine Tumor Center, Texas Back Institute, Plano, Texas
| | - Christopher J DeWald
- 8Department of Orthopaedic Surgery, Rush University Medical Center, Chicago, Illinois
| | - Michael T Nolte
- 8Department of Orthopaedic Surgery, Rush University Medical Center, Chicago, Illinois
| | - Matthew W Colman
- 8Department of Orthopaedic Surgery, Rush University Medical Center, Chicago, Illinois
| | - Frank M Phillips
- 8Department of Orthopaedic Surgery, Rush University Medical Center, Chicago, Illinois
| | - Daniel E Gelb
- 9Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, Maryland
| | - Jacob Bruckner
- 9Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, Maryland
| | - Lindsey B Ross
- 10Department of Neurologic Surgery, Cedars-Sinai Medical Center, Los Angeles
| | - J Patrick Johnson
- 10Department of Neurologic Surgery, Cedars-Sinai Medical Center, Los Angeles
| | - Terrence T Kim
- 11Department of Orthopaedics, Cedars-Sinai Medical Center, Los Angeles, California
| | - Neel Anand
- 11Department of Orthopaedics, Cedars-Sinai Medical Center, Los Angeles, California
| | - Joseph S Cheng
- 12Department of Neurosurgery, University of Cincinnati College of Medicine, Cincinnati, Ohio; and
| | - Zach Plummer
- 12Department of Neurosurgery, University of Cincinnati College of Medicine, Cincinnati, Ohio; and
| | - Paul Park
- 13Department of Neurosurgery, University of Michigan, Ann Arbor, Michigan
| | - Mark E Oppenlander
- 13Department of Neurosurgery, University of Michigan, Ann Arbor, Michigan
| | | | - Kristen E Jones
- 1Department of Orthopaedic Surgery, University of Minnesota, Minneapolis
| | - David W Polly
- 1Department of Orthopaedic Surgery, University of Minnesota, Minneapolis
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Wang T, Wei C, Gu S, Wu Y, Liu Y, Ma Y, Yin Q. Radio-anatomical study of anterior-posterior placement sacroiliac screw channel. Eur Spine J 2022. [PMID: 35687271 DOI: 10.1007/s00586-022-07257-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2022] [Revised: 04/19/2022] [Accepted: 05/01/2022] [Indexed: 10/18/2022]
Abstract
PURPOSE The outlet of the classic sacroiliac screw (SIS) cannot be precisely controlled by aiming devices, which may lead to malpositioned implants and neurovascular and visceral injury. This study aimed to radio-anatomically measure the parameters of the channel for anterior-posterior placement SIS (AP-SIS), which can be placed percutaneously with an aiming device. METHODS Pelvic CT scan data of 80 healthy adults (40 males and 40 females) with an average age of 45 years (range 20-70 years) were collected. The length (L), width (W), height (H), cortical bone spacing (M), camber angle (E), anteversion angle (F), cross-sectional safety angle (P) and sagittal safety angle (Q) of the channel were measured by CT or Mimics software. RESULTS The L, W, H, M, E, F, P and Q measures of S1 were 109.2 ± 8.0 mm, 18.5 ± 1.9 mm, 21.7 ± 1.7 mm, 8.1 ± 0.4 mm, 44.2 ± 3.2°, 42.4 ± 3.6°, 16.8 ± 1.1°, and 19.4 ± 2.0°, respectively, for S1, and 113.5 ± 9.4 mm, 18.2 ± 1.5 mm, 21.7 ± 1.7 mm, 7.7 ± 0.4 mm, 44.7 ± 3.2°, 31.2 ± 2.7°, 13.8 ± 1.0° and 15.4 ± 1.4°, respectively, for S2. Of the L measures, the intra-iliac segment was slightly longer than the intra-sacral segment. All parameters showed significant sex-related differences (p < 0.05). CONCLUSION The AP-SIS channels of S1-2 have sufficient width and length to accommodate a cancellous screw with a Φ 7.0-8.0 mm and a length 90-130 mm. The intra-iliac segment is a long channel screw with better mechanical properties over classic SIS.
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8
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Hey HWD, Ramos MRD, Tay HW, Lin S, Liu KG, Wong HK. The lateral entry point S2 alar-iliac (L- S2AI) screw: a preoperative computed tomography analysis of adult spinal deformity patients. Spine Deform 2022; 10:669-78. [PMID: 35088384 DOI: 10.1007/s43390-021-00462-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2021] [Accepted: 12/11/2021] [Indexed: 10/19/2022]
Abstract
PURPOSE To radiographically compare lateral entry point S2-alar-iliac (L-S2AI) screw with conventional S2AI (C-S2AI) and conventional iliac screw (CIS) lengths and trajectories. METHODS Twenty-five preoperative CT scans of consecutive patients undergoing adult spinal deformity realignment surgery over a random 2-year period were analysed. Maximum in-bone length, caudal and lateral trajectories of CIS, C-S2AI, and L-S2AI screws were measured and compared using One-way ANOVA with Tukey's post hoc tests. Multivariate logistic regression was performed to identify predictors of high screw length discrepancy between C-S2AI and L-S2AI. RESULTS Potential screw length was longest for CIS, followed by L-S2AI, then C-S2AI (114.5 ± 8.3 mm vs 101.4 ± 9.6 mm vs 80.6 ± 5.9 mm, respectively) in all patients (p < 0.001). Actual screw lengths found both CIS and L-S2AI to be longer than C-S2AI (95.3 ± 8.5 mm and 93.4 ± 7.5 mm vs 82.1 ± 7.3 mm; p = 0.008 and 0.003). Potential lateral angulation was smallest for CIS, followed by L-S2AI, then C-S2AI (21.9 ± 7.0° vs 31.9 ± 7.1° vs 40.9 ± 6.7°, respectively) in all patients (p < 0.001). L-S2AI and C-S2AI had the same caudal angulation (24.9 ± 6.8°), which was smaller than CIS (30.8 ± 5.8°) in all patients (p < 0.001). Univariate, but not multivariate analysis, revealed that lumbar lordosis > 40° (OR 7.2, p = 0.041), diagnosis of degenerative spondylolisthesis (OR 10.5, p = 0.017), and > 7 instrumented levels (OR 2.6, p = 0.049) were significantly associated with high screw discrepancies. CONCLUSION The L-S2AI screw combines advantages of CIS and C-S2AI screws, which includes increased screw length, reduced lateral angulation, a low-profile screw head, ease of connection to proximal hardware, and the biomechanical advantage of a quadcortical purchase.
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9
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Good CR, Orosz LD, Thomson AE, Schuler TC, Haines CM, Bhatt FR, Boyd D, Grossman KM, Roy R, Jazini E. Robotic-guidance allows for accurate S2AI screw placement without complications. J Robot Surg 2021; 16:1099-1104. [PMID: 34853954 DOI: 10.1007/s11701-021-01345-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Accepted: 11/21/2021] [Indexed: 11/28/2022]
Abstract
The study design is retrospective, multi-surgeon, single-center review. The objective is to evaluate complication rates, revision rates, and accuracy grading for robotic-guided S2 alar-iliac (S2AI) screws. Sixty-five consecutive patients underwent S2AI fixation (118 screws) as part of a posterior spine fusion using robotic-guidance. Screws were placed percutaneously in 14 cases and 51 were placed in an open fashion by three board-certified spine surgeons using the Mazor core technology robotic systems (Mazor X, n = 42; Mazor XSE, n = 23). Medical charts were retrospectively reviewed for revisions and complications. All patients were followed for 90 days or greater. Postoperative CT scans were obtained in 22 of the 51 patients, allowing for 46 screws to be reviewed by an independent neuroradiologist who graded the screws for accuracy. There were no intraoperative or postoperative complications associated with S2AI screw placement. There were no revisions found to be related to the S2AI screw placement. All 46 screws evaluated with postoperative CT scans were reported as being at the highest level of accuracy, grade A, with a breach distance of 0 mm (no breach). The robotic-guided technique for S2AI screw placement is a reliable method to achieving pelvic fixation with low complication and revision rates. In addition, a high degree of accuracy can be achieved without relying on visible and tactile landmarks needed for the freehand technique or the additional radiation associated with fluoroscopic-guidance.
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Affiliation(s)
- Christopher R Good
- Virginia Spine Institute, 11800 Sunrise Valley Drive, Reston, VA, 20191, USA.
| | | | - Alexandra E Thomson
- Virginia Spine Institute, 11800 Sunrise Valley Drive, Reston, VA, 20191, USA
| | - Thomas C Schuler
- Virginia Spine Institute, 11800 Sunrise Valley Drive, Reston, VA, 20191, USA
| | - Colin M Haines
- Virginia Spine Institute, 11800 Sunrise Valley Drive, Reston, VA, 20191, USA
| | - Fenil R Bhatt
- Virginia Spine Institute, 11800 Sunrise Valley Drive, Reston, VA, 20191, USA
| | - David Boyd
- Reston Radiology Consultants, Reston, VA, USA
| | | | - Rita Roy
- National Spine Health Foundation, Reston, VA, USA
| | - Ehsan Jazini
- Virginia Spine Institute, 11800 Sunrise Valley Drive, Reston, VA, 20191, USA
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10
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de Andrada Pereira B, Wangsawatwong P, Lehrman JN, Sawa AGU, Lindsey DP, Yerby SA, Godzik J, Waguespack AM, Uribe JS, Kelly BP. Biomechanics of a laterally placed sacroiliac joint fusion device supplemental to S2 alar-iliac fixation in a long-segment adult spinal deformity construct: a cadaveric study of stability and strain distribution. J Neurosurg Spine 2021; 36:42-52. [PMID: 34534964 DOI: 10.3171/2021.3.spine202175] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 03/01/2021] [Indexed: 11/06/2022]
Abstract
OBJECTIVE S2 alar-iliac (S2AI) screw fixation effectively enhances stability in long-segment constructs. Although S2AI fixation provides a single transarticular sacroiliac joint fixation (SIJF) point, additional fixation points may provide greater stability and attenuate screw and rod strain. The objectives of this study were to evaluate changes in stability and pedicle screw and rod strain with extended distal S2AI fixation and with supplemental bilateral integration of two sacroiliac joint fusion devices implanted using a traditional minimally invasive surgical approach. METHODS Eight L1-pelvis human cadaveric specimens underwent pure moment (7.5 Nm) and compression (400 N) tests under 4 conditions: 1) intact (pure moment loading only); 2) L2-S1 pedicle screw and rod with L5-S1 interbody fusion; 3) added S2AI screws; and 4) added bilateral laterally placed SIJF. Range of motion (ROM), rod strain, and screw-bending moment (S1 and S2AI) were analyzed. RESULTS Compared with S1 fixation, S2AI fixation significantly reduced L5-S1 ROM in right lateral bending by 50% (0.11°, p = 0.049) and in compression by 39% (0.22°, p = 0.003). Compared with fixation ending at S1, extending fixation with S2AI significantly decreased sacroiliac joint ROM by 52% (0.28°, p = 0.02) in flexion, by 65% (0.48°, p = 0.04) in extension, by 59% (0.76°, p = 0.02) in combined flexion-extension, and by 36% (0.09°, p = 0.02) in left axial rotation. The addition of S2AI screws reduced S1 screw-bending moment during flexion (0.106 Nm [43%], p = 0.046). With S2AI fixation, posterior L5-S1 primary rod strain increased by 124% (159 μE, p = 0.002) in flexion, by 149% (285 μE, p = 0.02) in left axial rotation, and by 99% (254 μE, p = 0.04) in right axial rotation. Compared with S2AI fixation, the addition of SIJF reduced L5-S1 strain during right axial rotation by 6% (28 μE, p = 0.04) and increased L5-S1 strain in extension by 6% (28 μE, p = 0.02). CONCLUSIONS Long-segment constructs ending with S2AI screws created a more stable construct than those ending with S1 screws, reducing lumbosacral and sacroiliac joint motion and S1 screw-bending moment in flexion. These benefits, however, were paired with increased rod strain at the lumbosacral junction. The addition of SIJF to constructs ending at S2AI did not significantly change SI joint ROM or S1 screw bending and reduced S2AI screw bending in compression. SIJF further decreased L5-S1 rod strain in axial rotation and increased it in extension.
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Affiliation(s)
- Bernardo de Andrada Pereira
- 1Spinal Biomechanics Laboratory, Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona
| | - Piyanat Wangsawatwong
- 1Spinal Biomechanics Laboratory, Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona
| | - Jennifer N Lehrman
- 1Spinal Biomechanics Laboratory, Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona
| | - Anna G U Sawa
- 1Spinal Biomechanics Laboratory, Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona
| | | | | | - Jakub Godzik
- 3Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona; and
| | | | - Juan S Uribe
- 3Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona; and
| | - Brian P Kelly
- 1Spinal Biomechanics Laboratory, Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona
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11
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Martin CT, Polly DW, Holton KJ, San Miguel-Ruiz JE, Albersheim M, Lender P, Sembrano JN, Hunt MA, Jones KE. Acute failure of S2-alar-iliac screw pelvic fixation in adult spinal deformity: novel failure mechanism, case series, and review of the literature. J Neurosurg Spine 2021; 36:53-61. [PMID: 34479206 DOI: 10.3171/2021.2.spine201921] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Accepted: 02/16/2021] [Indexed: 11/06/2022]
Abstract
OBJECTIVE Pelvic fixation with S2-alar-iliac (S2AI) screws is an established technique in adult deformity surgery. The authors' objective was to report the incidence and risk factors for an underreported acute failure mechanism of S2AI screws. METHODS The authors retrospectively reviewed a consecutive series of ambulatory adults with fusions extending 3 or more levels, and which included S2AI screws. Acute failure of S2AI screws was defined as occurring within 6 months of the index surgery and requiring surgical revision. RESULTS Failure occurred in 6 of 125 patients (5%) and consisted of either slippage of the rods or displacement of the set screws from the S2AI tulip head, with resultant kyphotic fracture. All failures occurred within 6 weeks postoperatively. Revision with a minimum of 4 rods connecting to 4 pelvic fixation points was successful. Two of 3 (66%) patients whose revision had less fixation sustained a second failure. Patients who experienced failure were younger (56.5 years vs 65 years, p = 0.03). The magnitude of surgical correction was higher in the failure cohort (number of levels fused, change in lumbar lordosis, change in T1-pelvic angle, and change in coronal C7 vertical axis, each p < 0.05). In the multivariate analysis, younger patient age and change in lumbar lordosis were independently associated with increased failure risk (p < 0.05 for each). There was a trend toward the presence of a transitional S1-2 disc being a risk factor (OR 8.8, 95% CI 0.93-82.6). Failure incidence was the same across implant manufacturers (p = 0.3). CONCLUSIONS All failures involved large-magnitude correction and resulted from stresses that exceeded the failure loads of the set plugs in the S2AI tulip, with resultant rod displacement and kyphotic fractures. Patients with large corrections may benefit from 4 total S2AI screws at the time of the index surgery, particularly if a transitional segment is present. Salvage with a minimum of 4 rods and 4 pelvic fixation points can be successful.
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Affiliation(s)
| | - David W Polly
- 1Department of Orthopaedic Surgery, University of Minnesota; and.,2Department of Neurosurgery, University of Minnesota, Minneapolis, Minnesota
| | - Kenneth J Holton
- 1Department of Orthopaedic Surgery, University of Minnesota; and
| | | | | | - Paul Lender
- 1Department of Orthopaedic Surgery, University of Minnesota; and
| | | | - Matthew A Hunt
- 2Department of Neurosurgery, University of Minnesota, Minneapolis, Minnesota
| | - Kristen E Jones
- 1Department of Orthopaedic Surgery, University of Minnesota; and.,2Department of Neurosurgery, University of Minnesota, Minneapolis, Minnesota
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12
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de Andrada Pereira B, Lehrman JN, Sawa AGU, Lindsey DP, Yerby SA, Godzik J, Waguespack AM, Uribe JS, Kelly BP. Biomechanical effects of a novel posteriorly placed sacroiliac joint fusion device integrated with traditional lumbopelvic long-construct instrumentation. J Neurosurg Spine 2021:1-10. [PMID: 34144523 DOI: 10.3171/2020.11.spine201540] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Accepted: 11/24/2020] [Indexed: 11/06/2022]
Abstract
OBJECTIVE S2-alar-iliac (S2AI) screw fixation effectively ensures stability and enhances fusion in long-segment constructs. Nevertheless, pelvic fixation is associated with a high rate of mechanical failure. Because of the transarticular nature of the S2AI screw, adding a second point of fixation may provide additional stability and attenuate strains. The objective of the study was to evaluate changes in stability and strain with the integration of a sacroiliac (SI) joint fusion device, implanted through a novel posterior SI approach, supplemental to posterior long-segment fusion. METHODS L1-pelvis human cadaveric specimens underwent pure moment (7.5 Nm) and compression (400 N) tests in the following conditions: 1) intact, 2) L2-S1 pedicle screw and rod fixation with L5-S1 interbody fusion, 3) added S2AI screws, and 4) added bilateral SI joint fixation (SIJF). The range of motion (ROM), rod strain, and screw bending moments (S1 and S2AI) were analyzed. RESULTS S2AI fixation decreased L2-S1 ROM in flexion-extension (p ≤ 0.04), L5-S1 ROM in flexion-extension and compression (p ≤ 0.004), and SI joint ROM during flexion-extension and lateral bending (p ≤ 0.03) compared with S1 fixation. SI joint ROM was significantly less with SIJF in place than with the intact joint, S1, and S2AI fixation in flexion-extension and lateral bending (p ≤ 0.01). The S1 screw bending moment decreased following S2AI fixation by as much as 78% in extension, but with statistical significance only in right axial rotation (p = 0.03). Extending fixation to S2AI significantly increased the rod strain at L5-S1 during flexion, axial rotation, and compression (p ≤ 0.048). SIJF was associated with a slight increase in rod strain versus S2AI fixation alone at L5-S1 during left lateral bending (p = 0.048). Compared with the S1 condition, fixation to S2AI increased the mean rod strain at L5-S1 during compression (p = 0.048). The rod strain at L5-S1 was not statistically different with SIJF compared with S2AI fixation (p ≥ 0.12). CONCLUSIONS Constructs ending with an S2AI screw versus an S1 screw tended to be more stable, with reduced SI joint motion. S2AI fixation decreased the S1 screw bending moments compared with fixation ending at S1. These benefits were paired with increased rod strain at L5-S1. Supplementation of S2AI fixation with SIJF implants provided further reductions (approximately 30%) in the sagittal plane and lateral bending SI joint motion compared with fixation ending at the S2AI position. This stability was not paired with significant changes in rod or screw strains.
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Affiliation(s)
| | | | - Anna G U Sawa
- 1Department of Neurosurgery, Spinal Biomechanics Laboratory, and
| | | | | | - Jakub Godzik
- 3Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona
| | | | - Juan S Uribe
- 3Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona
| | - Brian P Kelly
- 1Department of Neurosurgery, Spinal Biomechanics Laboratory, and
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Krieg SM, Sollmann N, Ille S, Albers L, Meyer B. Revision by S2-alar-iliac instrumentation reduces caudal screw loosening while improving sacroiliac joint pain-a group comparison study. Neurosurg Rev 2021; 44:2145-51. [PMID: 32914234 DOI: 10.1007/s10143-020-01377-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 08/10/2020] [Accepted: 08/20/2020] [Indexed: 11/25/2022]
Abstract
Lumbosacral instrumentation continues to be challenging due to complex biomechanical force distributions and poor sacral bone quality. Various techniques have therefore been established. The aim of this study was to investigate the outcome of patients treated with S2-alar-iliac (S2AI), S2-alar (S2A), and iliac (I) instrumentation as the most caudal level. Sixty patients underwent one of the 3 techniques between January 2012 and June 2017 (S2AI 18 patients, S2A 20 patients, I 22 patients). Mean age was 70.4 ± 8.5 years. Screw loosening (SL) and sacroiliac joint (SIJ) pain were evaluated during the course at 3-month and maximum follow-up (FU). All patients completed 3-month FU, the mean FU period was 2.5 ± 1.5 years (p = 0.38), and a median of 5 segments was operated on (p = 0.26), respectively. Bone mineral density (BMD), derived opportunistically from computed tomography (CT), did not significantly differ between the groups (p = 0.66), but cages were more frequently implanted in patients of the S2A group (p = 0.04). SL of sacral or iliac screws was more common in patients of the S2A and I groups compared with the S2AI group (S2AI 16.7%, S2A 55.0%, I 27.3% of patients; p = 0.03). SIJ pain was more often improved in the S2AI group not only after 3 months but also at maximum FU (S2AI 61.1%, S2A 25.0%, I 22.7% of patients showing improvement; p = 0.02). Even in shorter or mid-length lumbar or thoracolumbar constructs, S2AI might be considered superior to S2A and I instrumentation due to showing lower incidences of caudal SL and SIJ pain.
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14
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Hasan MY, Liu G, Wong HK, Tan JH. Postoperative complications of S2AI versus iliac screw in spinopelvic fixation: a meta-analysis and recent trends review. Spine J 2020; 20:964-972. [PMID: 31830594 DOI: 10.1016/j.spinee.2019.11.014] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Revised: 11/26/2019] [Accepted: 11/26/2019] [Indexed: 02/03/2023]
Abstract
BACKGROUND CONTEXT Iliac screw constructs have been a major advancement in spinopelvic fixation demonstrating superior biomechanics as compared with earlier pelvic spanning constructs. However, drawbacks such as screw site prominence and wound complication have led to the development of a lower profile S2AI iliac screw. PURPOSE In this study, we aimed to study the differences in complication rates between the traditional iliac and S2AI fixations via a pooled analysis of the available head-to-head comparisons between S2AI and iliac screws. We also aimed to study the iliac screw complications trend over the years particularly with reference to recent modifications in its screw insertion techniques. STUDY DESIGN A meta-analysis with attention to the comparison of patients who underwent iliac screws and S2AI screws was conducted. METHODS The following databases were utilized: PubMed, Scopus, Web of Science, Embase, and Cochrane Central Register of Controlled Trials database. Using the search terms: iliac, iliac bolts, S2AI, sacral 2 alar iliac, sacral two alar iliac, reviewers independently selected eligible studies, analyzed data and evaluated the risk of bias. Data analysis was conducted using RevMan 5.3 software. RESULT A total of 215 articles were identified, with 6 clinical studies directly comparing outcomes of S2AI pelvic fixation versus iliac screw fixation. A total of 477 patients were included, of which 255 patients (53.5%) underwent S2AI screw and 222 (46.5%) underwent iliac screw fixation. Our pooled analysis favored S2AI screws with regards to postoperative complications of screw prominence (odds ratio [OR]=5.99, 95% confidence interval [CI]=2.168-16.523, p<.001), screw loosening (OR=3.36, 95% CI=1.415-7.998, p=.006), implant breakage (OR=2.30, 95% CI=1.189-4.443, p=.013), and revision surgery (OR=7.84, 95% CI=3.224-19.080, p<.001). Although there was a trend toward more wound complications in conventional iliac screw techniques when compared with S2AI, it was not statistically significant. CONCLUSION Spinopelvic fixation is an evolving technique. The results from this study showed that S2AI screws with a lower profile have made a significant impact in reducing complications associated with conventional iliac screws. With recent entry point modification and further advancement in the conventional iliac screw technique, such as the "subcrestal iliac screw technique" which reduces the iliac screw complication rate but avoids S2AI-associated SIJ violation. Further studies may be needed to investigate whether these newer iliac screw techniques can narrow the difference in complication rates between iliac screws and S2AI screw techniques.
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Affiliation(s)
- Muhammed Yaser Hasan
- Department of Orthopaedic Surgery, University Spine Centre, National University Hospital, National University Health System, 1E Kent Ridge Rd, Singapore 119228, Singapore
| | - Gabriel Liu
- Department of Orthopaedic Surgery, University Spine Centre, National University Hospital, National University Health System, 1E Kent Ridge Rd, Singapore 119228, Singapore.
| | - Hee-Kit Wong
- Department of Orthopaedic Surgery, University Spine Centre, National University Hospital, National University Health System, 1E Kent Ridge Rd, Singapore 119228, Singapore
| | - Jun-Hao Tan
- Department of Orthopaedic Surgery, University Spine Centre, National University Hospital, National University Health System, 1E Kent Ridge Rd, Singapore 119228, Singapore
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Chang CC, Mummaneni PV, Rivera J, Mayer R, Chou D. Closure of L3 pedicle subtraction osteotomy via an open-bottom hinged table in 3D video. Neurosurg Focus Video 2020; 2:V6. [PMID: 36284696 PMCID: PMC9521217 DOI: 10.3171/2020.1.focusvid.19718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Accepted: 09/23/2019] [Indexed: 06/16/2023]
Abstract
Iatrogenic flat back deformity generally can be treated with a pedicle subtraction osteotomy (PSO) (Chan et al., 2018; Lu and Chou, 2007). One of the difficulties with PSO is that a controlled closure can sometimes be problematic in that there may be translation of the spine, manual pushing of the spine, and significant stress on the pedicle screws, which may risk loosening. The authors present a video of their surgical technique for PSO closed by passive closure using an open-bottom hinged table. This allows the osteotomy to be closed without any force on the screws and without significant manual forces on the spinal column. The video can be found here: https://youtu.be/pUECEjKdmSk.
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Affiliation(s)
- Chih-Chang Chang
- Department of Neurosurgery, University of California, San Francisco, California
- Department of Neurosurgery, Neurological Institute, Taipei Veterans General Hospital, Taipei
- School of Medicine, National Yang-Ming University, Taipei, Taiwan; and
| | | | | | - Rory Mayer
- Department of Neurosurgery, University of California, San Francisco, California
| | - Dean Chou
- Department of Neurosurgery, University of California, San Francisco, California
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16
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Nanda A, Manghwani J, Kluger PJ. Sacropelvic fixation techniques - Current update. J Clin Orthop Trauma 2020; 11:853-862. [PMID: 32879572 PMCID: PMC7452281 DOI: 10.1016/j.jcot.2020.07.022] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2020] [Revised: 07/22/2020] [Accepted: 07/22/2020] [Indexed: 10/23/2022] Open
Abstract
Sacropelvic is a complex junctional area owing to the complex regional anatomy and higher biomechanical stress. However extension of construct is indicated in cases with complex deformities, high grade spondylolisthesis, and complex fractures. The challenges remain which includes pseudoarthrosis and fixation failures. The fixation techniques have constantly evolved over time with better results with iliac screws and S2-alar-iliac screws. This article gives background on evolution, biomechanics, and recent update of use of robotics for sacropelvic fixation.
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Affiliation(s)
- Ankur Nanda
- Indian Spinal Injuries Centre, New Delhi, 110070, India
| | - Jitesh Manghwani
- Indian Spinal Injuries Centre, New Delhi, 110070, India,Corresponding author.
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17
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Laratta JL, Shillingford JN, Lombardi JM, Alrabaa RG, Benkli B, Fischer C, Lenke LG, Lehman RA. Accuracy of S2 Alar-Iliac Screw Placement Under Robotic Guidance. Spine Deform 2018; 6:130-136. [PMID: 29413734 DOI: 10.1016/j.jspd.2017.08.009] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Accepted: 08/12/2017] [Indexed: 01/08/2023]
Abstract
STUDY DESIGN Case series. OBJECTIVES To determine the safety and feasibility of S2 alar-iliac (S2AI) screw placement under robotic guidance. SUMMARY OF BACKGROUND DATA Similar to standard iliac fixation, S2AI screws aid in achieving fixation across the sacropelvic junction and decreasing S1 screw strain. Fortunately, the S2AI technique minimizes prominent instrumentation and the need for offset connectors to the fusion construct. Herein, we present an analysis of the largest series of robotic-guided S2AI screws in the literature without any significant author conflicts of interest with the robotics industry. METHODS Twenty-three consecutive patients who underwent spinopelvic fixation with 46 S2AI screws under robotic guidance were analyzed from 2015 to 2016. Screws were placed by two senior spine surgeons, along with various fellow or resident surgical assistants, using a proprietary robotic guidance system (Renaissance; Mazor Robotics Ltd., Caesara, Israel). Screw position and accuracy was assessed on intraoperative CT O-arm scans and analyzed using three-dimensional interactive viewing and manipulation of the images. RESULTS The average caudal angle in the sagittal plane was 31.0° ± 10.0°. The average horizontal angle in the axial plane using the posterior superior iliac spine as a reference was 42.8° ± 6.6°. The average S1 screw to S2AI screw angle was 11.3° ± 9.9°. Two violations of the iliac cortex were noted, with an average breach distance of 7.9 ± 4.8 mm. One breach was posterior (2.2%) and one was anterior (2.2%). The overall robotic S2AI screw accuracy rate was 95.7%. There were no intraoperative neurologic, vascular, or visceral complications related to the placement of the S2AI screws. CONCLUSIONS Spinopelvic fixation achieved using a bone-mounted miniature robotic-guided S2AI screw insertion technique is safe and reliable. Despite two breaches, no complications related to the placement of the S2AI screws occurred in this series. LEVEL OF EVIDENCE Level IV, therapeutic.
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Affiliation(s)
- Joseph L Laratta
- Department of Orthopaedic Surgery, Columbia University Medical Center, The Spine Hospital at New York Presbyterian, New York, NY, USA.
| | - Jamal N Shillingford
- Department of Orthopaedic Surgery, Columbia University Medical Center, The Spine Hospital at New York Presbyterian, New York, NY, USA
| | - Joseph M Lombardi
- Department of Orthopaedic Surgery, Columbia University Medical Center, The Spine Hospital at New York Presbyterian, New York, NY, USA
| | - Rami G Alrabaa
- Department of Orthopaedic Surgery, Columbia University Medical Center, The Spine Hospital at New York Presbyterian, New York, NY, USA
| | - Barlas Benkli
- Department of Orthopaedic Surgery, Columbia University Medical Center, The Spine Hospital at New York Presbyterian, New York, NY, USA
| | - Charla Fischer
- Department of Orthopaedic Surgery, The Hospital for Joint Diseases at New York University, New York, NY, USA
| | - Lawrence G Lenke
- Department of Orthopaedic Surgery, Columbia University Medical Center, The Spine Hospital at New York Presbyterian, New York, NY, USA
| | - Ronald A Lehman
- Department of Orthopaedic Surgery, Columbia University Medical Center, The Spine Hospital at New York Presbyterian, New York, NY, USA
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18
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Tavares Junior MCM, de Souza JPV, Araujo TPF, Marcon RM, Cristante AF, de Barros Filho TEP, Letaif OB. Comparative tomographic study of the S2-alar-iliac screw versus the iliac screw. Eur Spine J 2018; 28:855-862. [PMID: 30382431 DOI: 10.1007/s00586-018-5806-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2018] [Accepted: 10/24/2018] [Indexed: 11/27/2022]
Abstract
AIMS Iliac screws and S2-alar-iliac screws provide adequate mechanical stability for the fixation of lumbosacral spine pathologies, which has led to a significant increase in the use of these techniques in the routine practice of spine surgeons. However, studies on the ideal technical positioning for both techniques are limited. STUDY DESIGN This is an observational, retrospective, analytical descriptive study. OBJECTIVE To analyze, describe and compare the insertion and positioning parameters of the S2-alar-iliac and iliac screw techniques in adult patients without spinal deformities. METHODS The present study comprises a retrospective analysis of lumbosacral computed tomography images selected continuously in 2016 from 25 patients at a university hospital. Mann-Whitney-Shapiro-Wilk tests were performed. Data reliability was assessed using intraclass correlation. RESULTS The mean length of the iliac screw was greater than that of the S2-alar-iliac screw, and the S2-alar-iliac screw sat 20.5 mm deeper than the iliac screw. The mean of the greatest bone thickness for the iliac screw was 20.72 mm; that of the S2-alar-iliac screw was 23.24 mm. The mean distance from the iliac screw entry point to the skin was 32.46 mm, and the mean distance from the S2-alar-iliac screw entry point to the skin was 52.87 mm. CONCLUSION The trajectory of the S2-alar-iliac screws studied via computed tomography was greater in terms of bone thickness and deeper relative to the skin compared with the iliac screws. The S2-alar-iliac technique may have desirable clinical advantages in terms of the diameter of the screws and reduced protrusion when used in adults. These slides can be retrieved from Electronic supplementary material.
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Affiliation(s)
| | - João Paço Vaz de Souza
- Department of Orthopedics and Traumatology, IOT HCFMUSP, 171 Dr. Ovídio Pires de Campos St., São Paulo, SP, 05403010, Brazil
| | | | - Raphael Martus Marcon
- Department of Orthopedics and Traumatology, IOT HCFMUSP, 171 Dr. Ovídio Pires de Campos St., São Paulo, SP, 05403010, Brazil
| | - Alexandre Fogaça Cristante
- Department of Orthopedics and Traumatology, IOT HCFMUSP, 171 Dr. Ovídio Pires de Campos St., São Paulo, SP, 05403010, Brazil
| | | | - Olavo Biraghi Letaif
- Department of Orthopedics and Traumatology, IOT HCFMUSP, 171 Dr. Ovídio Pires de Campos St., São Paulo, SP, 05403010, Brazil
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19
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Lin JD, Tan LA, Wei C, Shillingford JN, Laratta JL, Lombardi JM, Kim YJ, Lehman RA, Lenke LG. The posterior superior iliac spine and sacral laminar slope: key anatomical landmarks for freehand S2-alar-iliac screw placement. J Neurosurg Spine 2018; 29:429-434. [PMID: 30052147 DOI: 10.3171/2018.3.spine171374] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECTIVE The S2-alar-iliac (S2AI) screw is an increasingly popular method for spinopelvic fixation. The technique of freehand S2AI screw placement has been recently described. The purpose of this study was to demonstrate, through a CT imaging study of patients with spinal deformity, that screw trajectories based on the posterior superior iliac spine (PSIS) and sacral laminar slope result in reliable freehand S2AI trajectories that traverse safely above the sciatic notch. METHODS Fifty consecutive patients (age ≥ 18 years) who underwent primary spinal deformity surgery were included in the study. Simulated S2AI screw trajectories were analyzed with 3D visualization software. The cephalocaudal coordinate for the starting point was 15 mm cephalad to the PSIS. The mediolateral coordinate for the starting point was in line with the lateral border of the dorsal foramina. The cephalocaudal screw trajectory was perpendicular to the sacral laminar slope. Screw trajectories, lengths, and distance above the sciatic notch were measured. RESULTS The mean sagittal screw angle (cephalocaudal angulation) was 44.0° ± 8.4° and the mean transverse angle (mediolateral angulation) was 37.3° ± 4.3°. The mean starting point was 5.9 ± 5.8 mm distal to the caudal border of the S1 foramen. The mean screw length was 99.9 ± 18.6 mm. Screw trajectories were on average 8.5 ± 4.3 mm above the sciatic notch. A total of 97 of 100 screws were placed above the sciatic notch. In patients with transitional lumbosacral anatomy, the starting point on the lumbarized/sacralized side was 3.4 mm higher than on the contralateral unaffected side. CONCLUSIONS The PSIS and sacral laminar slope are two important anatomical landmarks for freehand S2AI screw placement.
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Affiliation(s)
- James D Lin
- 1Department of Orthopedic Surgery, Columbia University Medical Center, The Spine Hospital at NewYork-Presbyterian/Allen, New York, New York
| | - Lee A Tan
- 2Department of Neurological Surgery, University of California San Francisco Medical Center, San Francisco, California; and
| | - Chao Wei
- 3Department of Spine Surgery, The First Affiliated Hospital of Fujian Medical University, Fuzhou, Fujian, People's Republic of China
| | - Jamal N Shillingford
- 1Department of Orthopedic Surgery, Columbia University Medical Center, The Spine Hospital at NewYork-Presbyterian/Allen, New York, New York
| | - Joseph L Laratta
- 1Department of Orthopedic Surgery, Columbia University Medical Center, The Spine Hospital at NewYork-Presbyterian/Allen, New York, New York
| | - Joseph M Lombardi
- 1Department of Orthopedic Surgery, Columbia University Medical Center, The Spine Hospital at NewYork-Presbyterian/Allen, New York, New York
| | - Yongjung J Kim
- 1Department of Orthopedic Surgery, Columbia University Medical Center, The Spine Hospital at NewYork-Presbyterian/Allen, New York, New York
| | - Ronald A Lehman
- 1Department of Orthopedic Surgery, Columbia University Medical Center, The Spine Hospital at NewYork-Presbyterian/Allen, New York, New York
| | - Lawrence G Lenke
- 1Department of Orthopedic Surgery, Columbia University Medical Center, The Spine Hospital at NewYork-Presbyterian/Allen, New York, New York
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Sutterlin CE, Field A, Ferrara LA, Freeman AL, Phan K. Range of motion, sacral screw and rod strain in long posterior spinal constructs: a biomechanical comparison between S2 alar iliac screws with traditional fixation strategies. J Spine Surg 2016; 2:266-276. [PMID: 28097243 DOI: 10.21037/jss.2016.11.01] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND S1 screw failure and L5/S1 non-union are issues with long fusions to S1. Improved construct stiffness and S1 screw offloading can help avoid this. S2AI screws have shown to provide similar stiffness to iliac screws when added to L3-S1 constructs. We sought to examine and compare the biomechanical effects on an L2-S1 pedicle screw construct of adding S2AI screws, AxiaLIF, L5-S1 interbody support via transforaminal lumbar interbody fusion (TLIF), and to examine the effect of the addition of cross connectors to each of these constructs. METHODS Two S1 screws and one rod with strain gauges (at L5/S1) were used in L2-S1 screw-rod constructs in 7 L1-pelvis specimens (two with low BMD). ROM, S1 screw and rod strain were assessed using a pure-moment flexibility testing protocol. Specimens were tested intact, and then in five instrumentation states consisting of: (I) Pedicle screws (PS) L2-S1; (II) PS + S2AI screws; (III) PS + TLIF L5/S1; (IV) PS + AxiaLIF L5/S1; (V) PS + S2AI + AxiaLIF L5/S1. The five instrumentation conditions were also tested with crosslinks at L2/3 and S1/2. Tests were conducted in flexion-extension, lateral bending and axial torsion with no compressive preload. RESULTS S2A1 produces reduced S1 screw strain for flexion-extension, lateral bending and axial torsion, as well as reduced rod strain in lateral bending and axial torsion in comparison to AxiaLIF and interbody instrumentation, at the expense of increased rod flexion-extension strain. Cross-connectors may have a role in further reduction of S1 screw and rod strain. CONCLUSIONS From a biomechanical standpoint, the use of the S2AI technique is at least equivalent to traditional iliac screws, but offers lower prominence and ease of assembly compared to conventional sacroiliac stabilization.
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Affiliation(s)
- Chester E Sutterlin
- Department of Neurosurgery, University of Florida, Gainesville, Florida, USA;; Spinal Health International, Longboat Key, Florida, USA
| | - Antony Field
- Auckland City Hospital and Starship Children's Hospital, Grafton, Auckland 1023, New Zealand
| | | | - Andrew L Freeman
- Excelen Center for Bone and Joint Research and Education, Minneapolis, USA
| | - Kevin Phan
- NeuroSpine Research Group (NSURG), Prince of Wales Private Hospital, Sydney, Australia;; University of New South Wales (UNSW), Sydney, Australia
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Abstract
Adult deformity patients often require fixation to the sacrum and pelvis for construct stability and improved fusion rates. Although certain sacropelvic fixation techniques can be challenging, the availability of intraoperative navigation has made many of these techniques more feasible. In this video case presentation, the authors demonstrate the techniques of S-1 bicortical screw and S-2-alar-iliac screw fixation under intraoperative navigation in a 67-year-old female. This instrumentation placement was part of an overall T-10-pelvis construct for the correction of adult spinal deformity. The video can be found here: https://youtu.be/3HZo-80jQr8 .
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Affiliation(s)
| | - Andre M Jakoi
- Orthopaedic Surgery, Keck School of Medicine, University of Southern California, Los Angeles, California
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