Acute failure of S2-alar-iliac screw pelvic fixation in adult spinal deformity: novel failure mechanism, case series, and review of the literature

2021 ◽  
pp. 1-9
Author(s):  
Christopher T. Martin ◽  
David W. Polly ◽  
Kenneth J. Holton ◽  
Jose E. San Miguel-Ruiz ◽  
Melissa Albersheim ◽  
...  
Keyword(s):  
Failure Mechanism ◽  
Lumbar Lordosis ◽  
Adult Spinal Deformity ◽  
Case Series ◽  
Vertical Axis ◽  
Consecutive Series ◽  
Adult Deformity ◽  
Pelvic Fixation ◽  
Fixation Points ◽  
Acute Failure

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.

scholarly journals Beyond Pelvic Incidence–Lumbar Lordosis Mismatch: The Importance of Assessing the Entire Spine to Achieve Global Sagittal Alignment

2017 ◽  
Vol 7 (6) ◽  
pp. 536-542 ◽  
Author(s):  
Robert K. Merrill ◽  
Jun S. Kim ◽  
Dante M. Leven ◽  
Joung Heon Kim ◽  
Samuel K. Cho
Keyword(s):  
Lumbar Lordosis ◽  
Pelvic Incidence ◽  
Adult Spinal Deformity ◽  
Case Series ◽  
Vertical Axis ◽  
Retrospective Case ◽  
Sagittal Vertical Axis ◽  
Global Sagittal Alignment ◽  
Sagittal Parameters ◽  
Combined Parameters

Study Design: Retrospective case series. Objective: To investigate which sagittal parameters contribute to a normal sagittal vertical axis (SVA) when there is a pelvic incidence-lumbar lordosis (PI-LL) mismatch >10° following adult spinal deformity (ASD) correction. Methods: We performed a retrospective review of ASD patients with >5 levels fused. Sagittal measurements between cohorts of postoperative PI-LL >10° and PI-LL<10° were compared. We correlated SVA to pelvic tilt (PT), thoracic kyphosis (TK), PI-LL, cervical lordosis (CL), and correlated the pre- to postoperative change in SVA to change in PT, change in TK, change in PI-LL, and change in CL. We also correlated SVA and the change in SVA to combined parameters of ((PI-LL) − PT + TK). Results: We analyzed 52 patients with a mean age of 59 ± 16 years. In patients with a postoperative SVA <5cm, a smaller TK was seen when PI-LL >10° than when PI-LL<10° (15.45° vs 33.04°, P = .0004). Additionally, PT was larger when PI-LL >10° than when PI-LL <10° (25.73° vs 19.07°, P = .006). SVA correlated better with ((PI-LL) − PT + TK) ( R2 = 0.51) than with PI-LL alone ( R2 = 0.33). Lastly, there was no significant correlation between change in pre- to postoperative SVA with change in TK for all cases ( P = .73), but in cases where change in PI-LL was <10°, there was a significant correlation between change in TK and change in SVA ( P = .009). Conclusion: Our results demonstrate that PT and TK, and not just PI-LL, play an important role in maintaining sagittal balance when there is a PI-LL mismatch >10°.

Outcomes of Surgical Treatment for One Hundred Thirty-Eight Patients With Severe Sagittal Deformity at a Minimum 2-Year Follow-up: A Case Series

2021 ◽  
Author(s):  
Justin K Scheer ◽  
Lawrence G Lenke ◽  
Justin S Smith ◽  
Darryl Lau ◽  
Peter G Passias ◽  
...  
Keyword(s):  
Adult Spinal Deformity ◽  
Case Series ◽  
Major Complication ◽  
Vertical Axis ◽  
Surgical Correction ◽  
Complication Rates ◽  
Sagittal Vertical Axis ◽  
Estimated Blood Loss ◽  
Sagittal Deformity

Abstract BACKGROUND Operative treatment of adult spinal deformity (ASD) can be very challenging with high complication rates. It is well established that patients benefit from such treatment; however, the surgical outcomes for patients with severe sagittal deformity have not been reported. OBJECTIVE To report the outcomes of patients undergoing surgical correction for severe sagittal deformity. METHODS Retrospective review of a prospective, multicenter ASD database. Inclusion criteria: operative patients age ≥18, sagittal vertical axis (SVA) ≥15 cm, mismatch between pelvic incidence and lumbar lordosis (PI-LL) ≥30°, and/or lumbar kyphosis ≥5° with minimum 2 yr follow-up. Health-related quality of life (HRQOL) scores including minimal clinically important difference (MCID)/substantial clinical benefit (SCB), sagittal and coronal radiographic values, demographic, frailty, surgical, and complication data were collected. Comparisons between 2 yr postoperative and baseline HRQOL/radiographic data were made. P &lt; .05 was significant. RESULTS A total of 138 patients were included from 502 operative patients (54.3% Female, Average (Avg) age 63.3 ± 11.5 yr). Avg operating room (OR) time 386.2 ± 136.5 min, estimated blood loss (EBL) 1829.8 ± 1474.6 cc. A total of 71(51.4%) had prior fusion. A total of 89.9% were posterior fusion only. Mean posterior levels fused 11.5 ± 4.1. A total of 44.9% had a 3-column osteotomy. All 2 yr postoperative radiographic parameters were significantly improved compared to baseline (P &lt; .001 for all). All 2yr HRQOL measures were significantly improved compared to baseline (P &lt; .004 for all). A total of 46.6% to 73.8% of patients met either MCID/SCB for all HRQOL. A total of 74.6% of patients had at least 1 complication, 11.6% had 4 or more complications, 33.3% had minimum 1 major complication, and 42(30.4%) had a postop revision. CONCLUSION Patients with severe sagittal malalignment benefit from surgical correction at 2 yr postoperative both radiographically and clinically despite having a high complication rate.

Evolution of Sagittal Imbalance Following Corrective Surgery for Sagittal Plane Deformity

Neurosurgery ◽  
2017 ◽  
Vol 81 (1) ◽  
pp. 129-134 ◽  
Author(s):  
Michael M. McDowell ◽  
Zachary J. Tempel ◽  
Gurpreet S. Gandhoke ◽  
Nicholas K. Khattar ◽  
D. Kojo Hamilton ◽  
...  
Keyword(s):  
Clinical Outcomes ◽  
Spinal Deformity ◽  
Sagittal Balance ◽  
Pelvic Tilt ◽  
Short Form ◽  
Adult Spinal Deformity ◽  
Sagittal Imbalance ◽  
Consecutive Series ◽  
Adult Deformity ◽  
Global Sagittal Alignment

Abstract BACKGROUND: Sagittal balance in adult spinal deformity is a major predictor of quality of life. A temporary loss of paraspinal muscle force and somatic pain following spine surgery may limit a patient's ability to maintain posture. OBJECTIVE: To assess the evolution of sagittal balance and clinical outcomes during recovery from adult spinal deformity surgery. METHODS: Retrospective review of a prospective observational database identified a consecutive series of patients with sagittal vertical axis (SVA) &gt; 40 mm undergoing adult deformity surgery. Radiographic parameters and clinical outcomes were measured out to 2 yr after surgery. RESULTS: A total of 113 consecutive patients met inclusion criteria. Mean preoperative SVA was 90.3 mm, increased to 104.6 mm in the first week, then gradually reduced at each follow-up interval to 59.2 mm at 6 wk, 45.0 mm at 3 mo, 38.6 mm at 6 mo, and 34.1 mm at 1 yr (all P &lt; .05). SVA did not change between 1 and 2 yr. Pelvic incidence-lumbar lordosis (PI-LL) corrected immediately from 25.3° to 8.5° (16.8° change; P &lt; .01) and a decreased pelvic tilt from 27.6° to 17.6° (10° change; P &lt; .01). No further change was noted in PI-LL. Pelvic tilt increased to 20.2° (P = .01) at 6 wk and held steady through 2 yr. Mean Visual Analog Scale, Oswestry Disability Index, and Short Form-36 scores all improved; pain rapidly improved, whereas disability measures improved as SVA improved. CONCLUSION: Radiographic assessment of global sagittal alignment did not fully reflect surgical correction of sagittal balance until 6 mo after adult deformity surgery. Sagittal balance initially worsened then steadily improved at each interval over the first year postoperatively. At 1 yr, all clinical and radiographic measures outcomes were significantly improved.

Characterizing Adult Cervical Deformity and Disability Based on Existing Cervical and Adult Deformity Classification Schemes at Presentation and Following Correction

Neurosurgery ◽  
2017 ◽  
Vol 82 (2) ◽  
pp. 192-201 ◽  
Author(s):  
Peter G Passias ◽  
Cyrus M Jalai ◽  
Justin S Smith ◽  
Virginie Lafage ◽  
Bassel G Diebo ◽  
...  
Keyword(s):  
Pelvic Tilt ◽  
Pelvic Incidence ◽  
Adult Spinal Deformity ◽  
Vertical Axis ◽  
Global Alignment ◽  
Sagittal Vertical Axis ◽  
Adult Deformity ◽  
Cervical Deformity ◽  
Curve Type ◽  
Horizontal Gaze

Abstract BACKGROUND Adult cervical deformity (ACD) classifications have not been implemented in a prospective ACD population and in conjunction with adult spinal deformity (ASD) classifications. OBJECTIVE To characterize cervical deformity type and malalignment with 2 classifications (Ames-ACD and Schwab-ASD). METHODS Retrospective review of a prospective multicenter ACD database. Inclusion: patients ≥18 yr with pre- and postoperative radiographs. Patients were classified with Ames-ACD and Schwab-ASD schemes. Ames-ACD descriptors (C = cervical, CT = cervicothoracic, T = thoracic, S = coronal, CVJ = craniovertebral) and alignment modifiers (cervical sagittal vertical axis [cSVA], T1 slope minus cervical lordosis [TS-CL], modified Japanese Ortphopaedic Association [mJOA] score, horizontal gaze) were assigned. Schwab-ASD curve type stratification and modifier grades were also designated. Deformity and alignment group distributions were compared with Pearson χ2/ANOVA. RESULTS Ames-ACD descriptors in 84 patients: C = 49 (58.3%), CT = 20 (23.8%), T = 9 (10.7%), S = 6 (7.1%). cSVA modifier grades differed in C, CT, and T deformities (P &lt; .019). In C, TS-CL grade prevalence differed (P = .031). Among Ames-ACD modifiers, high (1+2) cSVA grades differed across deformities (C = 47.7%, CT = 89.5%, T = 77.8%, S = 50.0%, P = .013). Schwab-ASD curve type and presence (n = 74, T = 2, L = 6, D = 2) differed significantly in S deformities (P &lt; .001). Higher Schwab-ASD pelvic incidence minus lumbar lordosis grades were less likely in Ames-ACD CT deformities (P = .027). Higher pelvic tilt grades were greater in high (1+2) cSVA (71.4% vs 36.0%, P = .015) and high (2+3) mJOA (24.0% vs 38.1%, P = .021) scores. Postoperatively, C and CT deformities had a trend toward lower cSVA grades, but only C deformities differed in TS-CL grade prevalence (0 = 31.3%, 1 = 12.2%, 2 = 56.1%, P = .007). CONCLUSION Cervical deformities displayed higher TS-CL grades and different cSVA grade distributions. Preoperative associations with global alignment modifiers and Ames-ACD descriptors were observed, though only cervical modifiers showed postoperative differences.

Patients with High Pelvic Tilt Achieve the Same Clinical Success as Those with Low Pelvic Tilt After Minimally Invasive Adult Deformity Surgery

Neurosurgery ◽  
2017 ◽  
Vol 83 (2) ◽  
pp. 270-276 ◽  
Author(s):  
Juan S Uribe ◽  
Jacob Januszewski ◽  
Michael Wang ◽  
Neel Anand ◽  
David O Okonkwo ◽  
...  
Keyword(s):  
Minimally Invasive ◽  
Spinal Deformity ◽  
Pelvic Tilt ◽  
Adult Spinal Deformity ◽  
Vertical Axis ◽  
Sagittal Vertical Axis ◽  
Adult Deformity ◽  
Radiographic Outcomes ◽  
Hrqol Data

Abstract BACKGROUND Pelvic tilt (PT) is a compensatory mechanism for adult spinal deformity patients to mitigate sagittal imbalance. The association between preop PT and postop clinical and radiographic outcomes has not been well studied in patients undergoing minimally invasive adult deformity surgery. OBJECTIVE To evaluate clinical and radiographic outcomes in adult spinal deformity patients with high and low preoperative PT treated surgically using less invasive techniques. METHODS Retrospective case-control, institutional review board-approved study. A multicenter, minimally invasive surgery spinal deformity patient database was queried for 2-yr follow-up with complete radiographic and health-related quality of life (HRQOL) data. Hybrid surgery patients were excluded. Inclusion criteria were as follows: age &gt; 18 and either coronal Cobb angle &gt; 20, sagittal vertical axis &gt; 5 cm, pelvic incidence-lumbar lordosis (PI-LL) &gt; 10 or PT &gt; 20. Patients were stratified by preop PT as per Schwab classification: low (PT&lt; 20), mid (PT 20-30), or high (&gt;30). Postoperative radiographic alignment parameters (PT, PI, LL, Cobb angle, sagittal vertical axis) and HRQOL data (Visual Analog Scale Back/Leg, Oswestry Disability Index) were evaluated and analyzed. RESULTS One hundred sixty-five patients had complete 2-yr outcomes data, and 64 patients met inclusion criteria (25 low, 21 mid, 18 high PT). High PT group had higher preop PI-LL mismatch (32.1 vs 4.7; P &lt; .001). At last follow-up, 76.5% of patients in the high PT group had continued PI-LL mismatch compared to 34.8% in the low PT group (P &lt; .006). There was a difference between groups in terms of postop changes of PT (–3.9 vs 1.9), LL (8.7 vs 0.5), and PI-LL (–9.5 vs 0.1). Postoperatively, HRQOL data (Oswestry Disability Index and Visual Analog Scale) were significantly improved in both groups (P &lt; .001). CONCLUSION Adult deformity patients with high preoperative PT treated with minimally invasive surgical techniques had less radiographic success but equivalent clinical outcomes as patients with low PT.

Bilateral open sacroiliac joint fusion during adult spinal deformity surgery using triangular titanium implants: technique description and presentation of 21 cases

2021 ◽  
pp. 1-7
Author(s):  
Christopher T. Martin ◽  
Kenneth J. Holton ◽  
Kristen E. Jones ◽  
Jonathan N. Sembrano ◽  
David W. Polly
Keyword(s):  
Adult Spinal Deformity ◽  
Titanium Implants ◽  
Lumbosacral Fusion ◽  
Intraoperative Ct ◽  
Adult Deformity ◽  
Pelvic Fixation ◽  
Joint Fusion ◽  
Iliac Screws ◽  
Si Joint ◽  
The Impact

OBJECTIVE Pelvic fixation enhances long constructs during deformity surgery. Subsequent loosening of iliac screws and pain at the pelvis occur in as many as 29% of patients. Concomitant sacroiliac (SI) fusion may prevent potential pain and failure. The objective of this study was to describe a novel surgical technique and a single institution’s experience using bilateral SI fusion during adult deformity surgery with S2-alar-iliac (S2AI) screws and triangular titanium rods (TTRs) placed with navigation. METHODS The authors reviewed open SI joint fusions with TTR performed between August 2019 and March 2020. All patients underwent lumbosacral fusion through a midline approach and bilateral S2AI pelvic fixation in the caudal teardrop, followed by TTR placement just proximal and cephalad to the S2AI screws using intraoperative CT imaging guidance. RESULTS Twenty-one patients were identified who received 42 TTRs, ranging in size from 7.0 × 65 mm to 7.0 × 90 mm. Three TTRs (7%) were malpositioned intraoperatively, and each was successfully repositioned during index surgery without negative sequelae. All breaches occurred in a medial and cephalad direction into the pelvis. Incremental operative time for adding TTR averaged 8 minutes and 33 seconds per implant. CONCLUSIONS Image-guided open SI joint fusion with TTR during lumbosacral fusion is technically feasible. The bony corridor for implant placement is narrower cephalad, and implants tend to deviate medially into the pelvis. Detection of malpositioned implant is aided with intraoperative CT, but this can be salvaged. A prospective randomized clinical trial is underway that will better inform the impact of this technique on patient outcomes.

P24. Acute failure of S2-alar-iliac pelvic fixation following adult deformity correction

2020 ◽  
Vol 20 (9) ◽  
pp. S158
Author(s):  
Christopher T. Martin ◽  
David W. Polly ◽  
Kenneth Holton ◽  
Jose San Miguel ◽  
Melissa Albersheim ◽  
...  
Keyword(s):  
Deformity Correction ◽  
Adult Deformity ◽  
Pelvic Fixation ◽  
Acute Failure

scholarly journals A Preliminary Algorithm Using Spine Measurement Software to Predict Sagittal Alignment Following Pedicle Subtraction Osteotomy

2017 ◽  
Vol 7 (6) ◽  
pp. 543-551
Author(s):  
Robert K. Merrill ◽  
Jun S. Kim ◽  
Dante M. Leven ◽  
Joshua J. Meaike ◽  
Joung Heon Kim ◽  
...  
Keyword(s):  
Lumbar Lordosis ◽  
Sagittal Alignment ◽  
Adult Spinal Deformity ◽  
Case Series ◽  
Pedicle Subtraction Osteotomy ◽  
Regression Equation ◽  
Sacral Slope ◽  
Pelvic Inclination ◽  
Manual Rotation ◽  
Measurement Software

Study Design: Retrospective case series. Objective: To evaluate if spine measurement software can simulate sagittal alignment following pedicle subtraction osteotomy (PSO). Methods: We retrospectively reviewed consecutive adult spinal deformity patients who underwent lumbar PSO. Sagittal measurements were performed on preoperative lateral, standing radiographs. Sagittal measurements after simulated PSO were compared to actual postoperative measurements. A regression equation was developed using cases 1-7 to determine the amount of manual rotation required of each film to match the simulated sagittal vertical axis (SVA) to the actual postoperative SVA. The equation was then applied to cases 8-13. Results: For all 13 cases, the spine software accurately simulated lumbar lordosis, pelvic incidence lumbar lordosis mismatch, and T1 pelvic angle, with no significant differences between actual and simulated measurements. The pelvic tilt (PT), sacral slope (SS), thoracolumbar alignment (TL), thoracic kyphosis (TK), T9 spino-pelvic inclination (T9SPi), T1 spino-pelvic inclination (T1SPi), and SVA were inaccurately simulated. The PT, SS, T9SPi, T1SPi, and SVA all change with manual rotation of the film, and by using the regression equation developed with cases 1-7, we were able to improve the accuracy and decrease the variability of the simulated PT, SS, T9SPi, T1SPi, and SVA for cases 8-13. Conclusions: Dedicated spine measurement software can accurately simulate certain sagittal measurements, such as LL, PI-LL, and TPA, following PSO. A number of measurements, including PT, SS, TL, TK, T9SPi, T1SPi, and SVA were inaccurately simulated. Our preliminary algorithm improved the accuracy and decreased the variability of certain measurements, but requires future prospective studies for further validation.

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