The lexicon of multirod constructs in adult spinal deformity: a concise description of when, why, and how

2021 ◽  
pp. 1-7
Keyword(s):  
Spinal Deformity ◽  
Adult Spinal Deformity ◽  
Pedicle Screws ◽  
Lumbosacral Junction ◽  
Coronal Balance ◽  
Clinical Scenarios ◽  
Iliac Screw ◽  
Correction Surgery ◽  
Rod Fracture ◽  
Concise Description

The use of multirod constructs in the setting of adult spinal deformity (ASD) began to prevent rod fracture and pseudarthrosis near the site of pedicle subtraction osteotomies (PSOs) and 3-column osteotomies (3COs). However, there has been unclear and inconsistent nomenclature, both clinically and in the literature, for the various techniques of supplemental rod implantation. In this review the authors aim to provide the first succinct lexicon of multirod constructs available for the treatment of ASD, providing a universal nomenclature and definition for each type of supplementary rod. The primary rod of ASD constructs is the longest rod that typically spans from the bottom of the construct to the upper instrumented vertebrae. The secondary rod is shorter than the primary rod, but is connected directly to pedicle screws, albeit fewer of them, and connects to the primary rod via lateral connectors or cross-linkers. Satellite rods are a 4-rod technique in which 2 rods span only the site of a 3CO via pedicle screws at the levels above and below, and are not connected to the primary rod (hence the term “satellite”). Accessory rods are connected to the primary rods via side connectors and buttress the primary rod in areas of high rod strain, such as at a 3CO or the lumbosacral junction. Delta rods span the site of a 3CO, typically a PSO, and are not contoured to the newly restored lordosis of the spine, thus buttressing the primary rod above and below a 3CO. The kickstand rod itself functions as an additional means of restoring coronal balance and is secured to a newly placed iliac screw on the side of truncal shift and connected to the primary rod; distracting against the kickstand then helps to correct the concavity of a coronal curve. The use of multirod constructs has dramatically increased over the last several years in parallel with the increasing prevalence of ASD correction surgery. However, ambiguity persists both clinically and in the literature regarding the nomenclature of each supplemental rod. This nomenclature of supplemental rods should help unify the lexicon of multirod constructs and generalize their usage in a variety of scientific and clinical scenarios.

scholarly journals Comparison of Radiographic And Clinical Outcomes Observed After Adult Spinal Deformity Correction Using Iliac Screw Versus S2-Alar-Iliac Screw

2021 ◽  
Author(s):  
Qiang Luo ◽  
Yong-Chan Kim ◽  
Ki-Tack Kim ◽  
Kee-Yong Ha ◽  
Joonghyun Ahn ◽  
...  
Keyword(s):  
Clinical Outcomes ◽  
Spinal Deformity ◽  
Lumbar Lordosis ◽  
Adult Spinal Deformity ◽  
Deformity Correction ◽  
Postoperative Change ◽  
Iliac Screw ◽  
Vas Scores ◽  
Correction Surgery

Abstract Background: To date, there is a paucity of reports clarifying the change of spinopelvic parameters in patients with adult spinal deformity (ASD) who underwent long segment spinal fusion using iliac screw (IS) and S2-alar-iliac screw (S2AI) fixation.Methods: A retrospective review of consecutive patients underwent deformity correction surgery for ASD between 2013 and 2017 was performed. Patients were divided into two groups based on whether IS or S2AI fixation was performed. All radiographic parameters were measured preoperatively, immediately postoperatively, and the last follow-up. Demographics, intraoperative and clinical data were analyzed between the two groups. Additionally, the cohort was subdivided according to the postoperative change in pelvic incidence (PI): subgroup (C) was defined as change in PI ≥5° and subgroup (NC) with change <5°. In subgroup analyses, the 2 different types of postoperative change of PI were directly compared.Results: A total of 142 patients met inclusion criteria: 111 who received IS and 31 received S2AI fixation. The IS group (65.6 ± 26, 39.8 ± 13.8) showed a significantly higher change in lumbar lordosis (LL) and upper lumbar lordosis (ULL) than the S2AI group (54.4 ± 17.9, 30.3 ± 9.9) (p<0.05). In subgroup (C), PI significantly increased from 53° preoperatively to 59° postoperatively at least 50% of IS cohort, with a mean change of 5.8° (p<0.05). The clinical outcomes at the last follow-up were significantly better in IS group than in S2AI group in terms of VAS scores for back and leg. The occurrence of sacroiliac joint pain and pelvic screw fracture were significantly greater in S2AI group than in IS group (25.8% vs 9%, p<0.05) and (16.1% vs 3.6%, p<0.05).Conclusions: IS fixation showed a greater change in LL and ULL than S2AI fixation in ASD surgery. PI may be changed under certain circumstances.

scholarly journals Use of iliac screw associated with more correction of lumbar lordosis than S2-alar-iliac screw for adult spinal deformity

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Qiang Luo ◽  
Yong-Chan Kim ◽  
Ki-Tack Kim ◽  
Kee-Yong Ha ◽  
Joonghyun Ahn ◽  
...  
Keyword(s):  
Spinal Deformity ◽  
Lumbar Lordosis ◽  
Pelvic Incidence ◽  
Adult Spinal Deformity ◽  
Deformity Correction ◽  
Postoperative Change ◽  
Iliac Screw ◽  
Vas Scores ◽  
Correction Surgery

Abstract Background To date, there is a paucity of reports clarifying the change of spinopelvic parameters in patients with adult spinal deformity (ASD) who underwent long segment spinal fusion using iliac screw (IS) and S2-alar-iliac screw (S2AI) fixation. Methods A retrospective review of consecutive patients who underwent deformity correction surgery for ASD between 2013 and 2017 was performed. Patients were divided into two groups based on whether IS or S2AI fixation was performed. All radiographic parameters were measured preoperatively, immediately postoperatively, and the last follow-up. Demographics, intraoperative and clinical data were analyzed between the two groups. Additionally, the cohort was subdivided according to the postoperative change in pelvic incidence (PI): subgroup (C) was defined as change in PI ≥5° and subgroup (NC) with change < 5°. In subgroup analyses, the 2 different types of postoperative change of PI were directly compared. Results A total of 142 patients met inclusion criteria: 111 who received IS and 31 received S2AI fixation. The IS group (65.6 ± 26°, 39.8 ± 13.8°) showed a significantly higher change in lumbar lordosis (LL) and upper lumbar lordosis (ULL) than the S2AI group (54.4 ± 17.9°, 30.3 ± 9.9°) (p < 0.05). In subgroup (C), PI significantly increased from 53° preoperatively to 59° postoperatively at least 50% of IS cohort, with a mean change of 5.8° (p < 0.05). The clinical outcomes at the last follow-up were significantly better in IS group than in S2AI group in terms of VAS scores for back and leg. The occurrence of sacroiliac joint pain and pelvic screw fracture were significantly greater in S2AI group than in IS group (25.8% vs 9%, p < 0.05) and (16.1% vs 3.6%, p < 0.05). Conclusions Compared with the S2AI technique, the IS technique usable larger cantilever force demonstrated more correction of lumbar lordosis, and possible increase in pelvic incidence. Further study is warranted to clarify the clinical impaction of these results.

scholarly journals Multi-Rod Constructs Can Prevent Rod Breakage and Pseudarthrosis at the Lumbosacral Junction in Adult Spinal Deformity

2017 ◽  
Vol 7 (6) ◽  
pp. 514-520 ◽  
Author(s):  
Robert K. Merrill ◽  
Jun S. Kim ◽  
Dante M. Leven ◽  
Joung Heon Kim ◽  
Samuel K. Cho
Keyword(s):  
Spinal Deformity ◽  
Adult Spinal Deformity ◽  
Lumbosacral Junction ◽  
Mechanical Instability ◽  
Surgical Exploration ◽  
Rod Breakage ◽  
One Year ◽  
Atrophic Nonunion ◽  
Rod Fracture

Study Design: Retrospective cohort study. Objective: To determine if patients fused with multi-rod constructs to the pelvis have a lower incidence of lumbosacral rod failure and pseudarthrosis than those fused with dual-rod constructs. Methods: We performed a retrospective review of consecutive adult spinal deformity patients who underwent long fusion to the pelvis. Inclusion criteria were >5 levels, primary fusion or revision for L5-S1 pseudarthrosis, and minimum 1-year follow-up. Revision patients with indications other than L5-S1 pseudarthrosis were excluded. One-year follow-up plain radiographs were reviewed for rod integrity, and computed tomography scan (CT) was obtained whenever rod breakage was observed. Dual-rod and multi-rod (3 or 4 rods) cohorts were statistically compared. Results: There were 31 patients with 15 in the dual-rod group and 16 in the multi-rod group, with average ages of 68 ± 9 and 63 ± 12 years, respectively. No patients in the multi-rod group experienced rod fracture, whereas 6 in the dual-rod group fractured a rod ( P = .007), with 4 occurring at the lumbosacral junction ( P = .04). CT scan in the 4 lumbosacral rod fracture cases, and surgical exploration in 3, confirmed pseudarthrosis and hypertrophic nonunion at the L5-S1 junction. Conclusion: Patients with dual-rod constructs had a statistically greater incidence of lumbosacral pseudarthrosis with implant failure than those with multi-rod constructs. CT and surgical exploration showed hypertrophic nonunion as opposed to oligo- or atrophic nonunion. This suggests that mechanical instability, not biology, is the main reason for failure, and could be addressed with the use of multi-rods.

Rod fracture after multiple-rod constructs for adult spinal deformity

2020 ◽  
Vol 32 (3) ◽  
pp. 407-414
Author(s):  
Jong-myung Jung ◽  
Seung-Jae Hyun ◽  
Ki-Jeong Kim ◽  
Tae-Ahn Jahng
Keyword(s):  
Spinal Deformity ◽  
Interbody Fusion ◽  
Adult Spinal Deformity ◽  
Multivariable Analysis ◽  
Consecutive Series ◽  
Lumbosacral Junction ◽  
Scoliosis Research Society ◽  
Radiological Parameters ◽  
Rod Fracture

OBJECTIVEThis study investigated the incidence and risk factors of rod fracture (RF) after multiple-rod constructs (MRCs) for adult spinal deformity (ASD) surgery.METHODSA single-center, single-surgeon consecutive series of adult patients who underwent posterior thoracolumbar fusion at 4 or more levels using MRCs after osteotomy with at least 1 year of follow-up were retrospectively reviewed. Patient characteristics, radiological parameters, operative data, and clinical outcomes (on the Scoliosis Research Society-22r questionnaire) were analyzed at baseline and follow-up.RESULTSSeventy-six patients were enrolled in this study. RF occurred in 9 patients (11.8%), with all cases involving partial rod breakage. Seven patients (9.2%) underwent revision surgery. There were no significant differences in baseline demographic characteristics, radiological parameters, and surgical factors between the RF and non-RF groups. Multivariable analysis revealed that interbody fusion at the L5–S1 and L4–S1 levels could significantly reduce the occurrence of RF after MRCs for ASD (adjusted odds ratios 0.070 and 0.035, respectively). The RF group had significantly worse function score (mean 2.9 ± 0.8 vs 3.5 ± 0.7) and pain score (mean 2.8 ± 1.0 vs 3.5 ± 0.8) compared with the non-RF group at last visit.CONCLUSIONSRF occurred in 11.8% of patients with MRCs after ASD surgery. Most RFs occurred at the lumbosacral junction or adjacent level (77%). Interbody fusion at the lumbosacral junction (L5–S1 or L4–S1 level) could significantly prevent the occurrence of RF after MRCs for ASD.

scholarly journals Risk Factors for Loosening of S2 Alar Iliac Screw: Surgical Outcomes of Adult Spinal Deformity

2020 ◽  
Vol 14 (6) ◽  
pp. 864-871
Author(s):  
Yasushi Iijima ◽  
Toshiaki Kotani ◽  
Tsuyoshi Sakuma ◽  
Keita Nakayama ◽  
Tsutomu Akazawa ◽  
...  
Keyword(s):  
Risk Factors ◽  
Spinal Deformity ◽  
Adult Spinal Deformity ◽  
Pedicle Screws ◽  
Screw Loosening ◽  
Lumbosacral Fusion ◽  
Bone Fusion ◽  
Iliac Screw ◽  
Independent Risk Factors ◽  
Upper Instrumented Vertebra

Study Design: Retrospective study.Purpose: To determine the risk factors for S2 alar iliac (S2AI) screw loosening and its association with lumbosacral fusion in patients with adult spinal deformity (ASD).Overview of Literature: S2AI screws have been widely used for ASD surgery in recent years. However, no studies have analyzed the risk factors for loosening of S2AI screws and its association with lumbosacral fusion.Methods: Cases of 50 patients with ASD who underwent long spinal fusion (>9 levels) with S2AI screws were retrospectively reviewed. Loosening of S2AI screws and S1 pedicle screws and bone fusion at the level of L5–S1 at 2 years after surgery were investigated using computed tomography. In addition, risk factors for loosening of S2AI screws were determined in patients with ASD. Results: At 2 years after surgery, 33 cases (66%) of S2AI screw loosening and six cases (12%) of S1 pedicle screw loosening were observed. In 40 of 47 cases (85%), bone fusion at L5–S1 was found. Pseudarthrosis at L5–S1 was not significantly associated with S2AI screw loosening (19.3% vs. 6.3%, <i>p</i>=0.23), but significantly higher in patients with S1 screw loosening (83.3% vs. 4.9%, <i>p</i><0.001). On multivariate logistic regression analyses, high upper instrumented vertebra (UIV) level (T5 or above) (odds ratio [OR], 4.4; 95% confidence interval [CI], 1.0–18.6; <i>p</i>=0.045) and obesity (OR, 11.4; 95% CI, 1.2–107.2; <i>p</i>=0.033) were independent risk factors for S2AI screw loosening.Conclusions: High UIV level (T5 or above) and obesity were independent risk factors for S2AI screw loosening in patients with lumbosacral fixation in surgery for ASD. The incidence of lumbosacral fusion is associated with S1 screw loosening, but not S2AI screw loosening.

scholarly journals Utilization of S1 Foraminal Hooks for Augmentation of S1 Screws in Adult Spinal Deformity Surgery: Comparative Study With Iliac Screws

Neurospine ◽  
2021 ◽  
Vol 18 (3) ◽  
pp. 554-561
Author(s):  
Ho Yong Choi ◽  
Dae Jean Jo
Keyword(s):  
Spinal Deformity ◽  
Adult Spinal Deformity ◽  
Statistical Significance ◽  
Sacral Slope ◽  
Protective Effects ◽  
Lumbosacral Junction ◽  
Sagittal Vertical Axis ◽  
Iliac Screws ◽  
Iliac Screw ◽  
Screw Group

Objective: To compare the outcomes of S1 foraminal hooks and iliac screws regarding fusion rate at the lumbosacral junction and protective effects on S1 screws.Methods: From January 2017 to December 2019, consecutive patients who underwent long fusions (uppermost instrumented vertebra at or above L1) to the sacrum for adult spinal deformity were enrolled. Patients were divided into S1 foraminal hook group and iliac screw group. Radiographic parameters and the incidence of pseudarthrosis and instrument failure at the lumbosacral junction were compared between the groups.Results: Twenty-nine patients (male:female = 1:28) with a mean age of 73.6 ± 6.8 years were evaluated. Sixteen patients (55.2%) had S1 foraminal hook fixation and 13 patients (44.8%) had iliac screw fixation. Lumbar lordosis, sacral slope, and sagittal vertical axis did not differ between the groups preoperatively and postoperatively. The rate of L5/S1 pseudarthrosis was significantly higher in S1 foraminal hook group (5 of 16, 31.3%), compared to iliac screw group (0 of 13, 0%; p = 0.048). Instrument failure at the lumbosacral junction trended toward a higher rate in S1 foraminal hook group (6 of 16, 37.5%) than in iliac screw group (1 of 13, 7.7%), without statistical significance (p = 0.09). Proximal junctional kyphosis/failure occurred less often in S1 foraminal hook group (2 of 16, 12.5%) than in iliac screw group (3 of 13, 30.8%) without statistical significance (p = 0.36).Conclusion: Treatment with S1 foraminal hooks achieved equivalent satisfactory sagittal correction with proportioned alignment compared to that with iliac screws. However, S1 foraminal hooks did not provide enough structural support to the lumbosacral junction in long fusions to the sacrum.

A Novel Junctional Tether Weave Technique for Adult Spinal Deformity: 2-Dimensional Operative Video

2018 ◽  
Vol 16 (2) ◽  
pp. E45-E46 ◽  
Author(s):  
Thomas J Buell ◽  
Jeffrey P Mullin ◽  
James H Nguyen ◽  
Davis G Taylor ◽  
Juanita Garces ◽  
...  
Keyword(s):  
Spinal Deformity ◽  
Lumbar Lordosis ◽  
Screw Fixation ◽  
Adult Spinal Deformity ◽  
Pedicle Screws ◽  
Iliac Crest Bone Graft ◽  
Cobalt Chromium ◽  
Sagittal Vertical Axis ◽  
Medical Publication ◽  
Iliac Screw

Abstract Proximal junctional kyphosis (PJK) is a common problem after multilevel spine instrumentation for adult spinal deformity. Various anti-PJK techniques such as junctional tethers for ligamentous augmentation have been proposed. We present an operative video demonstrating technical nuances of junctional tether “weave” application. A 70-yr-old male with prior L2-S1 instrumented fusion presented with worsening back pain and posture. Imaging demonstrated pathological loss of lumbar lordosis (flat back deformity), proximal junctional failure, and pseudarthrosis. The patient had severe global and segmental sagittal malalignment, with sagittal vertical axis (SVA, C7-plumbline) measuring 22.3 cm, pelvic incidence (PI) 55°, lumbar lordosis (LL) 8° in kyphosis, pelvic tilt (PT) 30°, and thoracic kyphosis (TK) 6°. The patient gave informed consent for surgery and use of imaging for medical publication. Briefly, surgery first involved re-instrumentation with bilateral pedicle screws from T10 to S1. After right-sided iliac screw fixation (left-sided iliac screw fixation was not performed due to extensive prior iliac crest bone graft harvesting), we then completed a L2-3 Smith–Petersen osteotomy, extended L4 pedicle subtraction osteotomy, and L3-4 interbody arthrodesis with a 12° lordotic cage (9 × 14 × 40 mm). Cobalt Chromium rods were placed spanning the instrumentation bilaterally, and accessory supplemental rods spanning the PSO were attached. An anti-PJK junctional tether “weave” was then implemented using 4.5 mm polyethylene tape (Mersilene tape [Ethicon, Somerville, New Jersey]). Postoperative imaging demonstrated improved alignment (SVA 2.8 cm, PI 55°, LL 53°, PT 25°, TK 45°) and no significant neurological complications occurred during convalescence or at 6 mo postop.

Strategies for prevention of rod fracture in adult spinal deformity: cobalt chrome rod, accessory rod technique, and lateral lumbar interbody fusion

2021 ◽  
pp. 1-10
Author(s):  
Ki Young Lee ◽  
Jung-Hee Lee ◽  
Kyung-Chung Kang ◽  
Sang-Kyu Im ◽  
Hae Seong Lim ◽  
...  
Keyword(s):  
Spinal Deformity ◽  
Interbody Fusion ◽  
Sagittal Alignment ◽  
Adult Spinal Deformity ◽  
Deformity Correction ◽  
Lumbar Interbody Fusion ◽  
Patient Factors ◽  
Rod Fracture ◽  
Cobalt Chrome

OBJECTIVERestoring the proper sagittal alignment in adult spinal deformity (ASD) can improve radiological and clinical outcomes, but pseudarthrosis including rod fracture (RF) is a common problematic complication. The purpose of this study was to analyze the methods for reducing the incidence of RF in deformity correction of ASD.METHODSThe authors retrospectively selected 178 consecutive patients (mean age 70.8 years) with lumbar degenerative kyphosis (LDK) who underwent deformity correction with a minimum 2-year follow-up. Patients were classified into the non-RF group (n = 131) and the RF group (n = 47). For predicting the crucial factors of RF, patient factors, radiographic parameters, and surgical factors were analyzed.RESULTSThe overall incidence of RF was 26% (47/178 cases), occurring in 42% (42/100 cases) of pedicle subtraction osteotomy (PSO), 7% (5/67 cases) of lateral lumbar interbody fusion (LLIF) with posterior column osteotomy, 18% (23/129 cases) of cobalt chrome rods, 49% (24/49 cases) of titanium alloy rods, 6% (2/36 cases) placed with the accessory rod technique, and 32% (45/142 cases) placed with the 2-rod technique. There were no significant differences in the incidence of RF regarding patient factors between two groups. While both groups showed severe sagittal imbalance before operation, lumbar lordosis (LL) was more kyphotic and pelvic incidence (PI) minus LL (PI-LL) mismatch was greater in the RF group (p < 0.05). Postoperatively, while LL and PI-LL did not show significant differences between the two groups, LL and sagittal vertical axis correction were greater in the RF group (p < 0.05). Nonetheless, at the last follow-up, the two groups did not show significant differences in radiographic parameters except thoracolumbar junctional angles. As for surgical factors, use of the cobalt chrome rod and the accessory rod technique was significantly greater in the non-RF group (p < 0.05). As for the correction method, PSO was associated with more RFs than the other correction methods, including LLIF (p < 0.05). By logistic regression analysis, PSO, preoperative PI-LL mismatch, and the accessory rod technique were crucial factors for RF.CONCLUSIONSGreater preoperative sagittal spinopelvic malalignment including preoperative PI-LL mismatch was the crucial risk factor for RF in LDK patients 65 years or older. For restoring and maintaining sagittal alignment, use of the cobalt chrome rod, accessory rod technique, or LLIF was shown to be effective for reducing RF in ASD surgery.

The Incidence of Iliac Screw-Related Complications After Long Fusion Surgery in Patients with Adult Spinal Deformity

Spine ◽  
2021 ◽  
Vol Publish Ahead of Print ◽  
Author(s):  
Tomohiro Banno ◽  
Tomohiko Hasegawa ◽  
Yu Yamato ◽  
Go Yoshida ◽  
Hideyuki Arima ◽  
...  
Keyword(s):  
Spinal Deformity ◽  
Adult Spinal Deformity ◽  
Fusion Surgery ◽  
Iliac Screw
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