Abstract Background Changes in spinal alignment and pelvic tilt alter acetabular orientation in predictable ways, which may have implications on stability of total hip arthroplasty (THA). Patients ...with sagittal spinal deformity represent a subset of patients who may be at particularly high risk of THA instability because of postural compensation for abnormal spinal alignment. Methods Using standing stereoradiography we evaluated the spinopelvic parameters, acetabular cup anteversion and inclination of 139 THAs in 107 patients with sagittal spinal deformity. Standing images were compared with supine pelvic radiographs to evaluate dynamic changes in acetabular cup position. Dislocation and revision rates were procured through retrospective chart review. The spinal parameters and acetabular cup positions among dislocators were compared with those who did not dislocate. Results The rate of THA dislocation in this cohort was 8.0%, with a revision rate of 5.8% for instability. Patients who sustained dislocations had significantly higher spinopelvic tilt, T1-pelvic angle, and mismatch of lumbar lordosis and pelvic incidence. Among all patients, 78% had safe anteversion while supine, which decreased significantly to 58% when standing due to increases in spinopelvic tilt. Among dislocating THA, 80% had safe anteversion, 80% had safe inclination, and 60% had both parameters within the safe zone. Conclusions In this cohort, patients with THA and concomitant spinal deformity have a particularly high rate of THA instability despite having an acetabular cup position traditionally thought of as within acceptable alignment. This dislocation risk may be driven by the degree of spinal deformity and by spinopelvic compensation. Surgeons should anticipate potential instability after hip arthroplasty and adjust their surgical plan accordingly.
Abstract Background Lumbar-pelvic fusion reduces the variation in pelvic tilt in functional situations by reducing lumbar spine flexibility, which is thought to be important in maintaining stability ...of a total hip arthroplasty (THA). We compared dislocation and revision rates for patients with lumbar fusion and subsequent THA to a matched comparison cohort with hip and spine degenerative changes undergoing only THA. Methods We identified patients in New York State who underwent primary elective lumbar fusion for degenerative disc disease pathology and subsequent THA between January 2005 and December 2012. A propensity score match was performed to compare 934 patients with prior lumbar fusion to 934 patients with only THA according to age, gender, race, Deyo comorbidity score, year of surgery, and surgeon volume. Revision and dislocation rates were assessed at 3, 6, and 12 months post-THA. Results At 12 months, patients with prior lumbar fusion had significantly increased rates of THA dislocation (control: 0.4%; fusion: 3.0%; P < .001) and revision (control: 0.9%; fusion: 3.9%; P < .001). At 12 months, fusion patients were 7.19 times more likely to dislocate their THA ( P < .001) and 4.64 times more likely to undergo revision ( P < .001). Conclusion Patients undergoing lumbar fusion and subsequent THA have significantly higher risks of dislocation and revision of their hip arthroplasty than a matched cohort of patients with similar hip and spine pathology but only undergoing THA. During preoperative consultation for patients with prior lumbar fusion, orthopedic surgeons must educate the patient and family about the increased risk of dislocation and revision.
Background Hip osteoarthritis often coexists with adult spinal deformity, an abnormality in which sagittal spinopelvic malalignment is present. Debate exists whether to perform spinal realignment ...correction or total hip arthroplasty first. Hip extension and pelvic tilt are important compensatory mechanisms in the setting of sagittal spinopelvic malalignment and change after spinal realignment. We performed this study to evaluate the effect that the spinal realignment surgical procedure has on acetabular anteversion. Methods This study is a retrospective review of a multicenter, prospective, consecutive database of patients with adult spinal deformity who underwent surgical spinal realignment. Only patients who already had undergone a total hip arthroplasty prior to the spinal realignment procedure were retained for analysis. Patients were excluded if they had insufficient imaging or large-head, metal-on-metal bearings or they had undergone revision total hip arthroplasty in the study period. Acetabular anteversion was calculated via the ellipse method on a standing, posterior-anterior, 90-cm radiograph with a well-centered pelvis. Anteversion was measured preoperatively and at six weeks or three months after the spinal realignment procedure. Spinopelvic parameters measured included pelvic incidence, pelvic tilt, sacral slope, lumbar lordosis, T 0005 pelvic angle, sagittal vertical axis, T1-spinopelvic inclination, and thoracic kyphosis. Results Forty-one hips (thirty-three patients) were identified. Acetabular anteversion significantly reduced (p < 0.001) after spinal correction by mean change of −4.96° (range, −22.32° to +2.36°). The change in anteversion correlated with the changes in sagittal pelvic orientation (0.828 for the pelvic tilt, −0.757 for the sacral slope, and −0.691 for the lumbar lordosis) and global spinopelvic alignment (0.579 for the sagittal vertical axis and 0.585 for the T 0005 pelvic angle). Regression analysis revealed that anteversion decreased by 1° for each of the following spinopelvic parameter changes (p < 0.001): 1.105° for spinopelvic tilt, 1.032° for sacral slope, and 3.163° for lumbar lordosis. Conclusions Patients with spinopelvic malalignment had a high prevalence of excessively anteverted acetabular components. Sagittal spinal correction following total hip arthroplasty resulted in reduced acetabular anteversion, which may have implications for stability. Changes in anteversion are most closely related to changes in pelvic tilt in an almost one-to-one ratio. Level of Evidence Therapeutic Level IV . See Instructions for Authors for a complete description of levels of evidence.
Anterior lumbar interbody fusion (ALIF) and lateral lumbar interbody fusion (LLIF) with percutaneous posterior screw fixation are two techniques used to address degenerative lumbar pathologies. ...Traditionally, these anterior-posterior (AP) surgeries involve repositioning the patient from the supine or lateral decubitus position to prone for posterior fixation. To reduce operative time (OpTime) and subsequent complications of prolonged anesthesia, single-position lumbar surgery (SPLS) is a novel, minimally invasive alternative performed entirely from the lateral decubitus position.
Assess the perioperative safety and efficacy of single position AP lumbar fusion surgery (SPLS).
Multicenter retrospective cohort study.
Three hundred and ninety patients undergoing AP surgery were included, of which 237 underwent SPLS and 153 were in the Flip group.
Outcome measures included levels fused, percentage of cases including L5-S1 fusion, fluoroscopy radiation dosage, OpTime, estimated blood loss (EBL), length of stay (LOS), and perioperative complications. Radiographic analysis included lumbar lordosis (LL), pelvic incidence, pelvic tilt, and segmental LL.
Patients undergoing primary ALIF and/or LLIF surgery with bilateral percutaneous pedicle screw fixation between L2-S1 were included over a 4-year period. Patients were classified as either traditional repositioned “Flip” surgery or SPLS. Outcome measures included levels fused, percentage of cases including L5-S1 fusion, fluoroscopy radiation dosage, OpTime, EBL, LOS, perioperative complications. Radiographic analysis included LL, pelvic incidence, pelvic tilt, and segmental LL. All measures were compared using independent samples t-tests and chi-squared analyses as appropriate with significance set at p < .05. Propensity matching was completed where demographic differences were found.
Three hundred and ninety patients undergoing AP surgery were included, of which 237 underwent SPLS and 153 were in the Flip group. Age, gender, BMI, and CCI were similar between groups. Levels fused (1.47 SPLS vs 1.52 Flip, p = .468) and percent cases including L5-S1 (31% SPLS, 35% Flip, p = .405) were similar between cohorts. SPLS significantly reduced OpTime (103 min vs 306 min, p < .001), EBL (97 vs 313 mL, p < .001), LOS (1.71 vs 4.12 days, p < .001), and fluoroscopy radiation dosage (32 vs 88 mGy, p < .001) compared to Flip. Perioperative complications were similar between cohorts with the exception of postoperative ileus, which was significantly lower in the SPLS group (0% vs 5%, p < .001). There was no significant difference in wound, vascular injury, neurological complications, or Venous Thrombotic Event. There was no significant difference found in 90-day return to operating room (OR).
SPLS improves operative efficiency in addition to reducing blood loss, LOS and ileus in this large cohort study, while maintaining safety.
The important relationship between sagittal spinal alignment and total hip arthroplasty (THA) is becoming well recognized. Prior research has shown a significant relationship between sagittal spinal ...deformity (SSD) and THA instability. This study aims at determining the prevalence of SSD among preoperative THA patients.
A multicenter database of preoperative THA patients was analyzed. Radiographic parameters measured from standing radiographs included anterior pelvic plane tilt, spinopelvic tilt, and lumbar lordosis (LL); pelvic incidence (PI) was measured from computed tomography scans. Lumbar flatback was defined as PI-LL mismatch >10°, balanced as PI-LL of −10° to 10°, and hyperlordosis as PI-LL <−10°.
A total of 1088 patients were analyzed (mean, 64 years; 48% female). And 59% (n = 644) of patients had balanced alignment, 16% (n = 174) had a PI-LL > 10°, and 4% (n = 46) had a PI-LL > 20° (severe flatback deformity). The prevalence of hyperlordosis was 25% (n = 270). Flatback patients tended to be older than balanced and hyperlordotic patients (69.5 vs 64.0 vs 60.8 years, P < .001). Spinopelvic tilt was more posterior in flatback compared to balanced and hyperlordotic patients (24.7° vs 15.4° vs 7.0°) as was anterior pelvic plane tilt (−7.1° vs −2.0° vs 2.5°) and PI (64.1° vs 56.8° vs 49.0°), all P < .001.
Only 59% of patients undergoing THA have normally aligned lumbar spines. Flatback SSD was observed in 16% (4% with severe flatback deformity) and there was a 25% prevalence of hyperlordosis. Lumbar flatback was associated with increasing age, posterior pelvic tilt, and larger PI. The relatively high prevalence of spinal deformity in this population reinforces the importance of considering spinopelvic alignment in THA planning and risk stratification.
Academic orthopedic journals and specialty societies emphasize the importance of two-year follow-up for patient-reported outcome measures (PROMS) after spine surgery, but there are limited data ...evaluating the appropriate length of follow-up.
To determine whether PROMs, as measured by the Oswestry Disability Index (ODI), would change significantly after 2-months postoperatively after lumbar decompression surgery for disc herniation or spinal stenosis.
Retrospective analysis of prospectively and consecutively enrolled patients undergoing lumbar decompression surgery between 2020 and 2021 from a single surgeon spine registry.
One hundred sixty-nine patients.
ODI, achievement of minimum clinically important difference (MCID), revisions.
Patients without a preoperative baseline score were excluded. Completion of the ODI questionnaire was assessed at the follow-up points. The median ODI was compared at time baseline, 2-month, 1-year and 2-year follow-up. Risk of reoperation was assessed with receiver operating characteristic (ROC) analysis to identify at-risk ODI thresholds of requiring reoperation.
Median ODI significantly improved at all time points compared to baseline (median baseline ODI: 40; 2-month ODI: 16, p=.001; 1-year ODI: 11.1, p=.001; 2-year ODI: 8, p=.001). Posthoc analysis demonstrated no difference between 2-months, 1-year and 2-year postoperative ODI (p=.9, p=.468, p=.606). The MCID was met in 87.9% of patients at 2 months, 80.7% at 1 year, and 87.3% at 2 years postoperatively. Twelve patients (7.7%) underwent revision surgery between 2 months and 2 years after the index surgery (median time to revision: 5.6 months). ROC curve analysis demonstrated that an ODI score ≥24 points at 2-months yielded a sensitivity of 85.7% and a specificity of 71.8% for predicting revision after lumbar decompression (AUC=0.758; 95% CI: 0.613–0.903). The Youden optimal threshold value of ≥24 points at 2-month postop ODI yielded an odd ratio (OR) for revision of 15.3 (CI: 1.8–131.8; p=.004). The positive predictive value (PPV) and negative predictive value (NPV) were 15.4% and 98.8%, respectively.
Two-year clinical follow-up may not be necessary for future peer-reviewed lumbar decompression surgery studies given that ODI plateaus at 8 weeks. Patients with a score ≥24 points at 2-months postoperatively have a higher risk of requiring a second surgery within the first 2 years and warrant continued follow-up.
Academic orthopedic journals and specialty societies emphasize the importance of two-year follow-up for patient-reported outcome measures (PROMS) after spine surgery, but there are limited data ...evaluating the appropriate length of follow-up.
To determine whether PROMs, as measured by the Oswestry Disability Index (ODI), would change significantly after 2-months postoperatively after lumbar decompression surgery for disc herniation or spinal stenosis.
Retrospective analysis of prospectively and consecutively enrolled patients undergoing lumbar decompression surgery between 2020 and 2021 from a single surgeon spine registry.
One hundred sixty-nine patients.
ODI, achievement of minimum clinically important difference (MCID), revisions.
Patients without a preoperative baseline score were excluded. Completion of the ODI questionnaire was assessed at the follow-up points. The median ODI was compared at time baseline, 2-month, 1-year and 2-year follow-up. Risk of reoperation was assessed with receiver operating characteristic (ROC) analysis to identify at-risk ODI thresholds of requiring reoperation.
Median ODI significantly improved at all time points compared to baseline (median baseline ODI: 40; 2-month ODI: 16, p=.001; 1-year ODI: 11.1, p=.001; 2-year ODI: 8, p=.001). Post-hoc analysis demonstrated no difference between 2-months, 1-year and 2-year postoperative ODI (p=.9, p=.468, p=.606). The MCID was met in 87.9% of patients at 2 months, 80.7% at 1 year, and 87.3% at 2 years postoperatively. Twelve patients (7.7%) underwent revision surgery between 2 months and 2 years after the index surgery (median time to revision: 5.6 months). ROC curve analysis demonstrated that an ODI score ≥24 points at 2-months yielded a sensitivity of 85.7% and a specificity of 71.8% for predicting revision after lumbar decompression (AUC=0.758; 95% CI: 0.613-0.903). The Youden optimal threshold value of ≥24 points at 2-month postop ODI yielded an odd ratio (OR) for revision of 15.3 (CI: 1.8-131.8; p=.004). The positive predictive value (PPV) and negative predictive value (NPV) were 15.4% and 98.8%, respectively.
Two-year clinical follow-up may not be necessary for future peer-reviewed lumbar decompression surgery studies given that ODI plateaus at 8 weeks. Patients with a score ≥24 points at 2-months postoperatively have a higher risk of requiring a second surgery within the first two years and warrant continued follow-up.
Recent research has demonstrated that patients with reduced pelvic mobility from standing to sitting have higher rates of dislocation after total hip arthroplasty (THA). This study evaluates the ...effect of sagittal spinal deformity, defined by pelvic incidence–lumbar lordosis mismatch (PI-LL), on postural changes in pelvic tilt (PT).
A multicenter database of 1100 preoperative THA patients was queried. Anterior-pelvic-plane tilt (APPt), spinopelvic tilt (SPT), and LL were measured from radiographs of patients in supine, standing, flexed-seated, and stepping-up postures; PI was measured from computed tomography. Patients were separated into 3 groups based on PI-LL (<−10°, −10° to 10°, >10°) and propensity-score matched by PI. Lumbar flatback-deformity was defined as PI-LL > 10°, hyperlordosis: PI-LL < −10°. SPT/APPt, including changes between each posture were compared across PI-LL groups using analysis of variance, with post-hoc Tukey tests. Pearson correlations were reported when testing associations between SPT/APPt change and PI-LL.
After propensity-score matching, 288 patients were analyzed (mean 65 y; 49% F). SPT and APPt change differed across all PI-LL categories from standing to seated, supine, and stepping-up with less SPT/APPt recruitment among hyperlordotic vs flatback patients (all P < .001). Greater PI-LL correlated with greater SPT recruitment from standing to seated (R = 0.294), supine (R = 0.292), and stepping-up (R = 0.207) (all P < .001). Smaller LL changes from standing to seated were associated with greater SPT recruitment (R = 0.372, P < .001).
Postural changes in SPT/APPt are associated with spinopelvic measures in THA candidates. Hyperlordotic patients tend to utilize their spines more compared with flatback patients who were more likely to recruit PT. Increased focus on patients with lumbar flatback and hyperlordosis may help in reducing prosthetic dislocation prevalence following THA.
STUDY DESIGN.Retrospective analysis.
OBJECTIVE.Determine whether deformity corrections should vary by pelvic incidence (PI).
SUMMARY OF BACKGROUND DATA.Alignment targets for deformity correction have ...been reported for various radiographic parameters. The T1 pelvic-angle (TPA) has gained in applications for adult spinal deformity (ASD) surgical-planning since it directly measures spinal alignment separate from pelvic- and lower-extremity compensation. Recent studies have demonstrated that ASD corrections should be age specific.
METHODS.A prospective database of consecutive ASD patients was analyzed in conjunction with a normative spine database. Clinical measures of disability included the Oswestry Disability Index (ODI) and Short Form 36 Survey (SF-36) Physical Component Score (PCS). Baseline relationships between TPA, age, PI, and ODI/SF-36 PCS scores were analyzed in the ASD and asymptomatic patients. Linear regression modeling was used to determine alignment targets based on PI and age-specific normative SF-36-PCS values.
RESULTS.Nine hundred three ASD patients (mean 53.7 yr) and 111 normative subjects (mean 50.7 yr) were included. Patients were subanalyzed by PIlow, medium, high (<40, 40–75, >75); and ageelderly (>65 yr, n = 375), middle age (45–65 yr, n = 387), and young (18–45 yr, n = 141). TPA and SRS-Schwab parameters correlated with age and PI in ASD and normative subjects (r = 0.42, P < 0.0001). ODI correlated with PCS (r = 0.71, P < 0.0001). Linear regression analysis using age-normative SF-36-PCS values demonstrated that ideal spinopelvic alignment is less strict with increasing PI and age.
CONCLUSION.Targets for ASD correction should vary by age and PI. This is demonstrated in both asymptomatic and ASD subjects. Using age-normative SF-36 PCS values, alignment targets are described for different age and PI categories. High-PI patients do not require as rigorous realignments to attain age-specific normative levels of health status. As such, sagittal spinal alignment targets increase with increasing age as well as PI.Level of Evidence3
