Acute Glaucoma Following Internal Carotid Artery Stenting: A Rare But Serious Complication of Ocular Ischemic Syndrome.

Acute glaucoma following carotid artery recanalization is a rare but severe complication of underlying ocular ischemic syndrome. We present a case of a 71-year-old woman with ocular ischemic syndrome and severe stenosis of the right internal and external carotid artery undergoing carotid artery stenting. Immediate postprocedural angiography showed pronounced reperfusion of the ophthalmic artery. Subsequently, the patient developed vision-threatening acute glaucoma despite treatment with acetazolamide. Monitoring of intraocular pressure is important in patients who are at risk of developing ocular ischemic syndrome because of internal carotid artery stenosis. Interventionalists should also assess the degree of vascular collateralization from the external carotid artery.

Safety and efficacy of long-term emicizumab prophylaxis in hemophilia A with factor VIII inhibitors: A phase 3b, multicenter, single-arm study (STASEY).

Background: The bispecific monoclonal antibody emicizumab bridges activated factor IX and factor X, mimicking the cofactor function of activated factor VIII (FVIII), restoring hemostasis. Objectives: The Phase 3b STASEY study was designed to assess the safety of emicizumab prophylaxis in people with hemophilia A (HA) with FVIII inhibitors. Methods: People with HA received 3 mg/kg emicizumab once weekly (QW) for 4 weeks followed by 1.5 mg/kg QW for 2 years. The primary objective was the safety of emicizumab prophylaxis, including incidence and severity of adverse events (AEs) and AEs of special interest (thrombotic events [TEs] and thrombotic microangiopathies). Secondary objectives included efficacy (annualized bleed rates [ABRs]). Results: Overall, 195 participants were enrolled; 193 received emicizumab. The median (range) duration of exposure was 103.1 (1.1-108.3) weeks. Seven (3.6%) participants discontinued emicizumab. The most common AEs were arthralgia (n = 33, 17.1%) and nasopharyngitis (n = 30, 15.5%). The most common treatment-related AE was injection-site reaction (n = 19, 9.8%). Two fatalities were reported (polytrauma with fatal head injuries and abdominal compartment syndrome); both were deemed unrelated to emicizumab by study investigators. Two TEs occurred (myocardial infarction and localized clot following tooth extraction), also deemed unrelated to emicizumab. The negative binomial regression model-based ABR (95% confidence interval) for treated bleeds was 0.5 (0.27-0.89). Overall, 161 participants (82.6%) had zero treated bleeds. Conclusions: The safety profile of emicizumab prophylaxis was confirmed in a large population of people with HA with FVIII inhibitors and no new safety signals occurred. The majority of participants had zero treated bleeds.

Dynamic stabilization for degenerative diseases in the lumbar spine: 2 years results.

Following lumbar fusion, adjacent segment degeneration has been frequently reported. Dynamic systems are believed to reduce main fusion drawbacks. We conducted a retrospective study on patients with degenerative lumbar disease treated with posterior dynamic stabilization with monoaxial hinged pedicular screws and lumbar decompression. VAS and ODI were used to compare clinical outcomes. As radiological outcomes, LL and SVA were used. 51 patients were included with an average follow-up of 24 months. 13 patients were revised because of postoperative radiculopathy (n=4), subcutaneous hematoma (n=2), L5 screw malposition (n=1) and adjacent segment disease (n=6). The mean ODI score 41 preoperatively compared to 36 postoperatively. The mean VAS scores for back and leg pain were 5.3 and 4.2, respectively compared to 4.5 and 4.0 postoperatively. The mean SVA was 5.3 cm preoperatively, and 5.7 cm postoperatively. The mean LL was 47.5° preoperatively and 45.5° postoperatively. From our data, which fail to show significant improvements and reflect a high revision rate, we cannot generally recommend dynamic stabilization as an alternative to fusion. Comparative trials with longer follow-ups are required.

The influence of isolated thoracoplasty on the evolution of pulmonary function after treatment of severe thoracic scoliosis.

INTRODUCTION AND PURPOSE: Isolated thoracoplasty (iTP) on the convex side is performed long time after scoliosis surgery has been performed. ITP is thought to cause a further decline in pulmonary function (PF); however, the amount of decline is ill defined. The objectives of this study were to examine the influence of iTP on the postoperative evolution of PF and rib hump reduction in patients that previously undergone scoliosis surgery. METHODS: Over an 11-year period, 75 patients underwent iTP. The authors performed a retrospective case series review. Patients with data from PF tests performed preoperatively and at the last follow-up were included. Minimum follow-up was 12 months. The PF value reported was predicted FVC (FVC%). According to the American Thoracic Society, pulmonary impairment was classified as no impairment (FVC: >80-100%), mild (FVC: >65 ≤80%), moderate (FVC: >50 ≤65), and severe (FVC ≤50%). The outcome was studied using validated measures (SRS-24 score, COMI, and the COPD Assessment Test (CAT)). The CAT is stratified into mild impairment (<10 pts), moderate impairment (10-20 pts), severe impairment (>20-30 pts), and disabled (>30 pts). RESULTS: Twenty-six patients fulfilled the inclusion criteria. The patients' average age was 28 years at surgery with iTP, and 22 were females; the average BMI was 23, and the average follow-up was 76 months. Twenty of the patients had AIS, and six had congenital scoliosis. The time between scoliosis correction and iTP averaged 39 months. The mean number of resected rib segments was 7, and the mean blood loss was 834 ml. FVC% was 66% preoperatively and 57% at follow-up, with a significant change of 9% (p < .02). Fourteen patients had a FVC% change between preoperation and follow-up that was ≥5%; this change was not dependent on the preoperative FVC%. PF showed a slight but non-significant improvement with longer follow-up. At the time of iTP, the thoracic curve averaged 67°, and thoracic kyphosis averaged 46°. Rib hump height was 34 mm before iTP and 15 mm at follow-up (p < .03). At follow-up, the SRS-24 score was 81, the COMI score was 4 points, and the CAT score was 8 points. Eight patients had a CAT >10. Two patients had a major complication. A comparison of patients with pulmonary impairment preoperation vs. follow-up found 4 vs. 1 patients had no PF impairment, 8 vs. 4 patients had mild impairment, 10 vs. 13 patients had moderate impairment, and 4 vs. 8 patients had severe impairment. CONCLUSIONS: Isolated TP was shown an effective technique for rib hump resection. Six years after iTP, the FVC% declined by an average of 9%. Several patients had long-lasting effects in terms of %FVC decline. iTP should be reserved for patients with significant rib hump deformity.

Selecting caudal fusion levels: 2 year functional and stiffness outcomes with matched pairs analysis in multilevel fusion to L5 versus S1.

PURPOSE: Controversy persists as to whether to end multilevel thoracolumbar fusions caudally at L5 or S1. Some argue that stopping at L5 may preserve greater function, but there are few data comparing functional limitations due to lumbar stiffness in patients with fusion to L5 versus S1. The aim of this study was to evaluate whether patients undergoing multilevel thoracolumbar fusions with an L5 caudal endpoint have a better lumbosacral function than patients with an S1 caudal endpoint. METHODS: Patients undergoing successful thoracolumbar fusion of 5 or more levels to L5 or S1, with solid fusion at 2 year follow-up, were examined from a single European center in addition to a multi-center North American database of 237 patients. In total, 40 patients with a distal stopping point of L5 were matched with a subset of 40 patients with a distal endpoint of S1 ± pelvic fixation. The L5 and S1 groups were matched for the final Oswestry Disability Index (ODI), Sagittal Vertical Axis (SVA C7-S1), number of fusion levels, and age. Impacts of lumbar stiffness on function as measured by the Lumbar Stiffness Disability Index (LSDI) were compared using the conditional logistic regression. RESULTS: After matching, there was no significant difference between the S1 and L5 groups for the final ODI (29.22 ± 21.6 for S1 versus 29.21 ± 21.7 for L5; p = 0.98), SVA (29.5 ± 40.3 mm for S1 versus 33.7 ± 37.1 mm for L5; p = 0.97), mean age (61.6 ± 11.0 years for S1 versus 58.3 ± 12.6 years for L5; p = 0.23), and number of fusion levels (9.7 ± 3.3 levels for S1 versus 9.0 ± 3 levels for L5; p = 0.34). The final 2-year postoperative LSDI scores were not significantly different between the S1 group (28.08 ± 21.47) and L5 group (29.21 ± 21.66) (hazard ratio 0.99, 95 % CI 0.97-1.03, p = 0.81). CONCLUSION: The analysis of patients with multilevel thoracolumbar fusions demonstrated that after minimum 2 year follow-up, self-reported functional impacts of lumbar stiffness were not significantly different between the patients with distal endpoints of L5 versus S1. The choice of distal fusion level of L5 does not appear to retain sufficient spinal flexibility to substantially affect postoperative function. LEVEL OF EVIDENCE: Level III.

Factors influencing radiographic and clinical outcomes in adult scoliosis surgery: a study of 448 European patients.

INTRODUCTION/PURPOSE: In adult scoliosis surgery (AS) delineation of risk factors contributing to failure is important to improve patient care. Treatment goals include deformity correction resulting in a balanced spine and horizontal lowest instrumented vertebra (LIV) in fusions not ending at S1. Therefore, the study objectives were to determine predictors for deformity correction, complications, revision surgery, and outcomes as well as to determine predictors of postoperative evolution of the LIV-take-off angle (LIV-TO) and symptomatic adjacent segment disease (ASD). METHODS: The authors performed a retrospective analysis of 448 patients who had AS surgery. Patients' age averaged 51 years, BMI 26, and follow-up of 40 months. According to the SRS adult scoliosis classification, 51 % of patients had major lumbar curves, 24 % each with single thoracic or double major curves. 54 % of patients had stable vertebra at L5 and 34 % of patients had fusion to S1. The mean number of posterior fusion levels was eight and implant density 73 %. Among standard radiographic measures of deformity the LIV-TO was assessed on neutral and bending/traction-films (bLIV-TO). Clinical outcomes were assessed in 145 patients with degenerative-type AS using validated measures (ODI, COMI and SF-36). Prediction analysis was conducted with stepwise multiple regression analyses. RESULTS: Preoperative thoracic curve (TC) was 53° and 33° at follow-up. Preoperative lumbar curve (LC) was 43° and 24° at follow-up. Curve flexibility was low (TC 34 %/LC 38 %). TC-correction (38 %) was predicted by preoperative TC (r = 0.9) and TC-flexibility (r = 0.8). LC-correction (50 %) was predicted by preoperative LC (r = 0.8), LC-flexibility (r = 0.8) and screw density (r = 0.7). Preoperative LIV-TO was 18.2° and at follow-up 9.4° (p < 0.01). 20 % of patients had a non-union (18 % at L5-S1). The risk for non-union at L5-S1 increased with age (p = 0.04), low screw density (p = 0.03), and postoperative sagittal imbalance [(T9-tilt (p = 0.01), C7-SVA (p = 0.01), LL (p = 0.01) and PI-LL mismatch (p = 0.01)]. 32 % of patients had revision surgery. Risk for revision was increased in fusions to S1 (p < 0.01), increased BMI (p < 0.01), sagittal imbalance (C7-SVA, p < 0.01), age (p = 0.02), and disc wedging distal to the LIV (p < 0.01). To a varying extent, clinical outcomes negatively correlated (p < 0.05) with revision, ASD, perioperative complications, age, low postoperative TC- and LC-correction, and sagittal and coronal imbalance at follow-up (C7-SVA, PT, and C7-CSVL). 59 patients had ASD, which correlated with preoperative and postoperative sagittal and coronal parameters of deformity. In a multivariate model, preoperative bLIV-TO (p < 0.01) and preoperative LIV-TO (p < 0.01) demonstrated the highest predictive strength for follow-up LIV-TO. CONCLUSION: In the current study, the magnitude of deformity correction in the sagittal and coronal planes was shown to have significant impact on radiographic and clinical outcomes as well as revision rates. Findings indicate that risks for complications might be reduced by restoration of sagittal balance, appropriate deformity correction and advanced lumbosacral fixation. The use of preoperative LIV-TO and LIV-TO on bending/traction-films were shown to be useful for surgical planning, selection of the LIV and prediction of follow-up-TO, respectively. Parameters of sagittal balance rather than coronal deformity predicted ASD.

Sagittal balance of the cervical spine: an analysis of occipitocervical and spinopelvic interdependence, with C-7 slope as a marker of cervical and spinopelvic alignment.

OBJECT: Sagittal malalignment of the cervical spine has been associated with worsened postsurgical outcomes. For better operative planning of fusion and alignment restoration, improved knowledge of ideal fusion angles and interdependences between upper and lower cervical spine alignment is needed. Because spinal and spinopelvic parameters might play a role in cervical sagittal alignment, their associations should be studied in depth. METHODS: The authors retrospectively analyzed digital lateral standing cervical radiographs of 145 patients (34 asymptomatic, 74 symptomatic; 37 surgically treated), including full-standing radiographs obtained in 45 of these patients. Sagittal measurements were as follows: C2-7, occiput (Oc)-C2, C1-2 Cobb angles, and C-7 slope (the angle between the horizontal line and the superior endplate of C-7), as well as T4-12 and L1-S1 Cobb angles, sacral slope, pelvic incidence, and C-7 sagittal vertical axis (SVA). A correlation analysis was performed, and linear regression models were developed. RESULTS: Statistical analyses revealed significant correlations between C2-7 and Oc-C2 (r = -0.4, p < 0.01), Oc-C2 (r = -0.3, p < 0.01), and C1-2 angle (r = -0.3, p < 0.01). C-7 slope was significantly correlated with C2-7 (r = -0.5, p < 0.01) and with Oc-C2 angle (r = 0.2, p = 0.02). Total cervical (Oc-C7) lordosis was 30.2° and did not differ significantly among asymptomatic, symptomatic, and surgically treated patients. Correlations between C2-7 and Oc-C2 alignment were stronger in asymptomatic patients (r = -0.5, p < 0.01) and surgically treated patients (r = -0.5, p < 0.01) than in symptomatic patients (r = -0.3, p = 0.01), but the between-group difference was not significant (p > 0.1). Comparing cervical and spinopelvic alignment revealed a significant correlation between sacral slope and C-7 slope (r = -0.3, p = 0.04) and C2-7 (r = 0.4, p < 0.01). The C-7 SVA correlated significantly with the C-7 slope (r = -0.4, p < 0.01). The interdependences were stronger within the occipitocervical parameters than between the cervical and remaining spinal parameters. CONCLUSIONS: Significant correlations between the upper and lower cervical spine exist, confirming the existence of inherent compensatory mechanisms to maintain overall balance; no significant differences were found among asymptomatic, symptomatic, and surgically treated patients. The C-7 slope is a useful marker of overall sagittal alignment, acting as a link between the occipitocervical and thoracolumbar spine.

Parameters leading to a successful radiographic outcome following surgical treatment for Lenke 2 curves.

INTRODUCTION: In Lenke 2 curves, there are conflicting data when to include the PTC into the fusion. Studies focusing on Lenke 2 curves are scant. The number of patients with significant postoperative shoulder height difference (SHD) or trunk shift (TS) is as high as 30 % indicating further research. Therefore, the purpose of the current study was to improve understanding of curve resolution and shoulder balance following surgical correction of Lenke 2 curves as well as the identification of radiographic parameters predicting postoperative curve resolution, shoulder and trunk balance in perspective of inclusion/exclusion of the proximal thoracic curve (PTC). METHODS: This is a retrospective study of a 158 Lenke 2 curves. Serial radiographs were analyzed for the main thoracic curve (MTC), PTC, and lumbar curve (LC), SHD, clavicle angle (CA), T-1 tilt, deviation of the central sacral vertical line (CSVL) off the C7 plumb line.Patients were stratified whether the PTC was included in the fusion (+PTC group, n = 60) or not (-PTC group, n = 98). Intergroup results were studied. Compensatory mechanisms for SHD were studied in detail. Adding-on distally was defined as an increase of the lowest instrumented vertebra adjacent disc angle (LIVDA) >3°. Stepwise regression analyses were performed to establish predictive radiographic parameters. RESULTS: At follow-up averaging 24 months significant differences between the +PTC and -PTC group existed for the PTC (24° vs 28°, p < .01), PTC correction (42 vs 29 %, p < .01), rate of MTC-loss >5° (27 vs 53 %, p < .01), and spontaneous LC correction in patients with a selective thoracic fusion (STF) (80/93 %, p = .04). The number of patients with a new trunk shift (CSVL > 2 cm) was 9 (6 %): 7 in the -PTC vs 2 in the +PTC group (p = .03). Utilization of compensatory mechanisms (99 vs 83 %, p < .01) and adding-on (35 vs 20 %, p < .05) occurred more often in the +PTC vs the -PTC groups. Statistics showed postoperative SHD improvement in both the +PTC and -PTC groups. There were no significant differences regarding SHD, CA and T1-Tilt between groups. However, only in the -PTC group, a significant change between postoperative and follow-up SHD existed (p = .02). Statistics identified a preoperative 'left shoulder up' (p < .01) and CSVL (p = .03) predictive for follow-up SHD ≥1.5 cm. A statistical model only for the -PTC group showed 9 parameters highly predictive for a follow-up SHD ≥1.5 cm with highest prediction strength for a PTC >40° (p = .01), a preoperative 'left shoulder up' (p < .01) and anterior fusion (p = .02). To account for baseline differences between the +PTC and -PTC groups, 49 matched-pairs were studied. Postoperative differences remained significant between the +PTC and -PTC groups for the PTC (p < .01), MTC (p = .03) and the rate of loss of MTC >5° (p < .01). CONCLUSION: Prediction of a successful surgical outcome for Lenke 2 curves depends on multiple variables, in particular a preoperative left shoulder up, preoperative PTC >40°, MTC correction, and surgical approach. Shoulder balance is not significantly different whether the PTC is included in the fusion or not. But, powerful compensation mechanisms utilized to balance shoulder in the -PTC group can impose changes of trunk alignment, main and compensatory lumbar curves.

Comparison of Anteroposterior to Posterior-Only Correction of Scheuermann's Kyphosis: A Matched-Pair Radiographic Analysis of 92 Patients.

STUDY DESIGN: Retrospective radiographic benchmark study. OBJECTIVE: To evaluate the amount of instrumented correction obtained from a combined anterior/posterior (A/P) versus posterior-only (post-only) approach for Scheuermann's kyphosis. SUMMARY OF BACKGROUND DATA: An A/P approach was thought to optimize correction; however, instrumentation advances using pedicle screws allow treatment through an all-posterior approach. METHODS: A total of 166 Scheuermann's kyphosis patients were treated between 2 centers: 90 by combined A/P approach at 1 center and 76 by post-only at the second center. From the 166 patients, a matched cohort of 92 (46 from each) was established according to preoperative sagittal (±10°) and hyperextension (HE) Cobb (±10°) measurements and matched for age and gender. RESULTS: In the matched-pair group, average preoperative sagittal Cobb angles were 75.9° for the A/P group versus 78.8° for the post-only group (p = .2). The HE Cobb angles were similar (52.4° vs. 51.1°; p = .6). They showed similar corrections (33.7° vs. 30.6°; p = .3) and postoperative Cobb measurements (43.4° vs. 47.1°; p = .2) as well. The number of fusion levels was 9 in the A/P group and 12 in the post-only group; the difference yielded significance (p = .02). CONCLUSIONS: The A/P and post-only approaches averaged similar degrees of correction. The A/P patients were likely to correct more than their preoperative HE sagittal Cobb measurement, whereas the post-only group corrected close to their preoperative HE measurement. The number of fusion levels was larger with the post-only group.

Cervical laminectomy and instrumented lateral mass fusion: techniques, pearls and pitfalls.

INTRODUCTION: Cervical laminectomy is a reliable tool for posterior decompression in various cervical spine pathologies. Although there is increasing evidence of superior clinical, neurological and radiological outcomes when using anterior cervical decompression, laminectomy can be a valuable tool when combined with instrumented lateral mass fusion for carefully selected indications. METHODS: Literature review. RESULTS: This review article will provide decision-making guidance, technical advice and pitfalls. The technical advice for laminectomy and instrumented lateral mass fusion is illustrated. The authors review the literature on outcomes and complications and suggest indications for the safe and successful application of cervical laminectomy and lateral mass fusion.

Scoliosis and chest cage deformity measures predicting impairments in pulmonary function: a cross-sectional study of 492 patients with scoliosis to improve the early identification of patients at risk.

STUDY DESIGN: This study examines the correlations between pulmonary function tests (PFTs) and radiographical measures of spinal deformities in patients with scoliosis. OBJECTIVE: To define the parameters that enable more accurate predictions of restricted pulmonary function (PF) in patients with scoliosis. SUMMARY OF BACKGROUND DATA: The early identification of patients with scoliosis who are at risk of developing severe curve progression and restricted PF is critical to improving patient care. METHODS: A total of 492 patients with a thoracic/thoracolumbar curve (TC) and preoperative PFTs as well as radiographical analysis of the TC and thoracic kyphosis (TK) were assessed. The forced vital capacity (FVC) was expressed as a percentage of the predicted value (FVC%). According to guidelines for the severity of pulmonary impairments, classifications were used: no impairment (FVC > 80%), mild (65 < FVC ≤ 80%), moderate (50 < FVC ≤ 65), and severe impairment (FVC ≤ 50%). Main radiographical parameters were included and statistical analyses were used to identify radiographical predictors and to develop prediction models. RESULTS: The average age was 17 years, 94% of the patients had adolescent idiopathic scoliosis, 20% had lordoscoliosis (TK <10°). The average FVC% was 75% ± 17%, their average TC was 57° ± 21°, and TK was 26° ± 25°. A total of 38% had no impairment, 37% exhibited mild impairment, 15% had moderate impairments, and 10% were severely impaired. Spinal deformities identified by radiographical analysis (TC, TC-flexibility, apical vertebral rotation, TK, and rib hump) significantly influenced FVC% (P < 0.01). TK logistic regression analysis revealed that 2 factors are predictive for an FVC 50% or less: increased scoliosis with a low TK less than 0° (odds ratio = 7.3) or a high TK more than 60° (odds ratio = 20). A model for predicting FVC values more than 50% was established and shown to achieve a correct classification rate of 94%. CONCLUSION: Patients with increasing coronal and sagittal plane deformities with a high thoracic scoliosis apex are at the highest risk for reduced FVC%. The models developed provided improved estimations of actual PF based on the magnitude of the radiographical deformity.

Criteria for successful correction of thoracolumbar/lumbar curves in AIS patients: results of risk model calculations using target outcomes and failure analysis.

INTRODUCTION: Failure to select the appropriate lowest instrumented vertebra (LIV) in selective lumbar fusion (SLF) for thoracolumbar/lumbar curves (LC) can result in adding-on in the lumbar curve (LC) or the need for fusion extension due to a decompensating thoracic curve (TC). The selection criteria that predict optimal outcomes still need to be refined. The objectives of the current study were to identify risk factors for failure of anterior scoliosis correction and fusion (ASF) as well as predictors of optimal outcomes and ASF efficacy for SLF. MATERIALS AND METHODS: A retrospective review of all patients (n = 245) with AIS who had anterior SLF at one institution was conducted. Optimal outcomes were defined as a target LC ≤ 20° and a target TC ≤ 30°. The distance from the LIV to the SV was recorded. An increase in the LIV adjacent level disc angulation (LIVDA) ≥ 5° was defined as adding-on. An increase in the TC at follow-up was defined as TC-progression. Stepwise univariate and multivariate linear and logistic regression analyses were performed to identify criteria predicting the target LC and TC. A total of 68 % of the patients had the LIV at SV-2 (=2 levels above stable vertebra). RESULTS: The patients' average age was 17 years, the average fusion length was 4.6 levels, and the average follow-up time was 32 months. The preoperative LC was 49 ± 14°, the LC-bending was 22 ± 13° (57 ± 18 %), and the follow-up LC was 25 ± 10°. LC correction was 59 ± 17% (p < 0.01). The preoperative TC was 39 ± 13°, the TC-bending was 21 ± 12°, and the follow-up TC was 29 ± 13°. The TC-correction was 32 ± 19% (p < 0.01). At follow-up, 85 patients (35%) had an LC ≤ 20°, 110 patients (45 %) had a TC ≤ 30°. The follow-up LC and an LC ≤ 20° were predicted by LC-bending (p < 0.01, r = 0.6), preoperative LC (p < 0.01, r = 0.6). The logistic regression models could define patients at risk for failing the target LC ≤ 20° or TC ≤ 30°. At follow-up, TC ≤ 30° was best predicted by the preoperative TC (p < 0.01, r = 0.8; OR 1.2) and TC-bending (p < 0.01, r = 0.8; OR 1.06), with the logistic regression model revealing a correct prediction in 84 % of all cases. Among the patients, 8 % required late posterior surgery. Patients achieving the target LC ≤ 20° had a significantly reduced risk for failure (p = 0.01). Selecting an LIV at SV-1 vs. SV-2 significantly increased the chance of achieving a target LC ≤ 20° (p = 0.01) and reduced the risk of adding-on (p < 0.01). Predictors for failure also included a high preoperative LC (p = 0.02; OR 0.97), TC-bending (p < 0.01), and preoperative TC (p = 0.01). A cut-off in the failure risk analysis was established at a TC of 38°. Additionally, a significant cut-off for risk of adding-on was established at LIVDA <3.5°. CONCLUSION: A high chance of achieving a target LC ≤ 20° and a low risk of revision was dependent on LC-bending, preoperative LC and TC, and a LIV at SV-1 with non-parallel LIVDA. Our risk model analysis may support the selection of a safe LIV to achieve the target LC.

Selective thoracic fusion in AIS curves: the definition of target outcomes improves the prediction of spontaneous lumbar curve correction (SLCC).

INTRODUCTION: The decision of when to use selective thoracic fusion (STF) and the prediction of spontaneous lumbar curve correction (SLCC) remain difficult. Using a novel methodological approach, the authors yielded for a better prediction of SLCC and analyzed the efficacy of anterior scoliosis correction and fusion (ASF). METHODS: A retrospective analysis of 273 patients treated with ASF for STF was performed. In total, 87 % of the patients showed a Lenke 1 curve pattern. The lumbar curve modifier was classified as A in 66 % of the patients, B in 21 % of the patients and C in 13 % of the patients. The fusion length averaged 6.7 levels. The analysis included an assessment of radiographic deformity and correction, surgery characteristics, complications and revisions and clinical outcomes to improve the prediction of SLCC. Patients with a Type A-L, Type B or Type C modifier were stratified into a target follow-up lumbar curve (LC) category of ≤20° or >20°. Linear regression analyses were performed to assess the accuracy of predicting LC magnitude, and a multivariate logistic regression model was built using the following preoperative (preop) predictors: main thoracic curve (MTC), LC, MTC-bending and LC-bending. The output variable indicated whether a patient had an LC >20° at follow-up. A variable selection algorithm was applied to identify significant predictors. Two thresholds (cut-offs) were applied to the test sample to create high positive and negative prediction values. The data from 33 additional patients were gathered prospectively to create an independent test sample to learn how the model performed with independent data as a test of the generalizability of the model. RESULTS: The average patient age was 17 years, and the average follow-up period was 33 months. The MTC was 53.1° ± 10.2° preoperatively, 29.8° ± 10.5° with bending and was 25.4° ± 9.7° at follow-up (p < 0.01). The LC was 35.7° ± 7.5° preoperatively, 8.9° ± 5.8° with bending, and 21.8° ± 7.0° at follow-up (p < 0.01). After applying a variable selection algorithm, the preop LC [p < 0.02, odds ratio (OR) = 1.09] and preop LC-bending (p < 0.009, OR = 1.14) remained in the model as significant predictors. The performance of the linear regression model was tested in an independent test sample, and the difference between the observed and predicted values was only 1° ± 4.5°. Based on the test sample, the lower threshold was set to 25 %, and the upper threshold was set to 75 %. Patients with prediction values of 25-75 % were identified by the model, but by definition of the model, no prediction was made. In the test sample, 87 % of the patients were correctly classified as having an LC ≤20° at follow-up, and 84 % of the patients were correctly classified as having an LC >20°. The model test in the independent test sample revealed that 100 % of the patients were correctly classified as having an LC ≤20°, and 86 % of the patients were correctly classified as having an LC >20°. CONCLUSION: After analyzing a sufficiently large sample of 273 patients who underwent ASF for STF, significant predictors for SLCC were established and reported according to the surgical outcomes. Application of the prediction models can aid surgeons in the decision-making process regarding when to perform STF. Our results indicate that with stratification of outcomes into target curves (e.g., an LC <20°), future benchmarks for STF might be more conclusive.

Surgical outcomes of scoliosis surgery in Marfan syndrome.

STUDY DESIGN: Retrospective review of a case series. OBJECTIVE: To present the radiologic and surgical characteristics of scoliosis treatment in patients with Marfan syndrome (MFS). SUMMARY OF BACKGROUND DATA: The treatment of scoliosis in MFS has been reported to pose unique challenges. However, the information on surgical outcomes is sparse. In clinical practice, surgery for scoliosis in MFS is reported to confer higher perioperative risks and instrumentation-related complications compared with adolescent idiopathic scoliosis because of atypical and rigid curve patterns and the underlying desmogenic disorder. METHODS: Database research identified 26 MFS patients treated surgically during 7 years at a single spine center. Three patients presented with previous failed surgeries and were excluded. The medical records, charts, and radiographs of 23 patients were analyzed focusing on curve characteristics, surgical outcomes including complications, and curve correction using modern third-generation hybrid or pedicle screw systems, and the behavior of junctional segments and compensatory curves. RESULTS: The sample included 18 female and 5 male patients with an average age of 18.2±9.2 years (13-52 y) at index surgery and 21.2±9.2 years (14-53 y) at follow-up, averaging 35.8±23.5 months (6-95 mo). According to the Lenke classification, 30% presented as type 1, 9% as type 2, 22% as type 3, 9% as type 4, 17% as type 5, and 13% of patients as type 6. Seventy-four percent of patients had a type C lumbar modifier. In total, 48% of patients underwent a posterior spinal fusion (PSF). Thirty percent had instrumented anterior spinal fusion (AISF), whereas 22% had a combined anterior release and staged PSF. Ninety-one percent of patients achieved solid fusion; there was 1 asymptomatic nonunion and 1 recalcitrant nonunion. Add-on phenomena were identified in 13% of patients (n=3) treated with AISF, indicating staged PSF once. In total, complications were encountered in 30% of patients, indicating redo surgery in 17% of patients. The cause for revision included nonunion (2x), liquor leakage (1x), and wound infection at the iliac crest (1x). We judged the outcome as excellent/good if the patient had no major redo surgery and was very satisfied/satisfied. Overall, excellent/good outcome was noted in 78% of the patients. Blood loss averaged 659 mL in AISF and 1748 mL in PSF. The surgical time was 193 minutes in AISF and 229 minutes in PSF. Preoperative, postoperative, and follow-up Cobb T4-T12 was 13, 13, and 16 degrees, respectively; the mean thoracic curves measured 66 (23-106), 36 (0-58), and 38 degrees (0-58), respectively. Lumbar curves measured 63 (23-110), 27 (0-80), and 24 degrees (0-68), respectively. Coronal plumb line measured 2.2, 2.6, and 1.2 cm, respectively, indicating good trunk balance in most patients. The flexibility rates of thoracic curves and lumbar curves were 38% and 47%, respectively. Thoracic curve correction in PSF and combined anterior release/PSF was 44%, and in AISF, it reached 57%. CONCLUSIONS: The current study highlights the potential pitfalls in scoliosis surgery for patients with MFS. Surgery was performed using third-generation pedicle screw-based and hook-based systems for PSF and second-generation and third-generation implants for AISF. We illustrated that the treatment of scoliosis in MFS, taking into account the individual challenges of the underlying desmogenic disorder, can be performed with a moderately increased risk for surgical complications compared with adolescent idiopathic scoliosis.

Surgical treatment of Scheuermann's kyphosis using a combined antero-posterior strategy and pedicle screw constructs: efficacy, radiographic and clinical outcomes in 111 cases.

INTRODUCTION: There is sparse literature on how best to correct Scheuermann's kyphosis (SK). The efficacy of a combined strategy with anterior release and posterior fusion (AR/PSF) with regard to correction rate and outcome is yet to be determined. MATERIALS AND METHODS: A review of a consecutive series of SK patients treated with AR/PSF using pedicle screw-rod systems was performed. Assessment of demographics, complications, surgical parameters and radiographs including flexibility and correction measures, proximal junctional kyphosis angle (JKA + 1) and spino-pelvic parameters was performed, focusing on the impact of curve flexibility on correction and clinical outcomes. RESULTS: 111 patients were eligible with a mean age of 23 years, follow-up of 24 months and an average of eight levels fused. Cobb angle at fusion level was 68° preoperatively and 37° postoperatively. Flexibility on traction films was 34 % and correction rate 47 %. Postoperative and follow-up Cobb angles were highly correlated with preoperative bending films (r = 0.7, p < 0.05). Screw density rate was 87 %, with increased correction with higher screw density (p < 0.001, r = 0.4). Patients with an increased junctional kyphosis angle (JKA + 1) were at higher risk of revision surgery (p = 0.049). 22 patients sustained complication, and 21 patients had revision surgery. 42 patients with ≥24 months follow-up were assessed for clinical outcomes (follow-up rate for clinical measures was 38 %). This subgroup showed no significant differences regarding baseline parameters as compared to the whole group. Median approach-related morbidity (ArM) was 8.0 %, SRS-sum score was 4.0, and ODI was 4 %. There was a significant negative correlation between the SRS-24 self-image scores and the number of segments fused (r = -0.5, p < 0.05). Patients with additional surgery had decreased clinical outcomes (SRS-24 scores, p = 0.004, ArM, p = 0.0008, and ODI, p = 0.0004). CONCLUSION: The study highlighted that AR/PSF is an efficient strategy providing reliable results in a large single-center series. Results confirmed that flexibility was the decisive measure when comparing surgical outcomes with different treatment strategies. Findings indicated that changes at the proximal junctional level were impacted by individual spino-pelvic morphology and determined by the individually predetermined thoracolumbar curvature and sagittal balance. Results stressed that in SK correction, reconstruction of a physiologic alignment is decisive to achieving good clinical outcomes and avoiding complications.

Morphological differences in adolescent idiopathic scoliosis: a histological and ultrastructural investigation.

STUDY DESIGN: Histological and ultrastructural evaluation of cell morphologies at the concave and convex side of apical intervertebral discs (IVD) of adolescent idiopathic scoliosis (AIS). OBJECTIVE: To determine changes in cell morphology, viability, and cell death after asymmetric disc loading in AIS and to compare the findings with the tilt angles. SUMMARY OF BACKGROUND DATA: The reaction of cells to loading stimuli in the IVD seems to be specific. Although dynamic loads are more beneficial to the disc cells and maintain the matrix biosynthesis, static compressive loads suppress gene expression. METHODS: Apical IVDs (Th8-Th9 to L1-L2) from 10 patients with AIS were studied histologically (including TUNEL [TdT-mediated dUTP-biotin nick end labeling] staining to identify disc cell death by apoptosis) and ultrastructurally for matrix evaluations and to quantify healthy, balloon, chondroptotic, apoptotic, and necrotic cells on the concave and convex sides. Patients' spines were classified according to the Lenke classification. Degeneration was assessed according to the Pfirrmann grading system. Two groups were established; group 1 (G1) with a tilt of 5° to 9° and group 2 (G2) with a tilt of 10° to 19°. RESULTS: Balloon cells were found in significantly higher numbers at the concave side (G1-annulus fibrosus [AF]: mean 16%), with almost none found at the convex side. Mean numbers of healthy cells did not show differences comparing both sides. Significantly higher numbers of healthy cells were found with increasing tilt angle at the concave side. Necrosis (mean, 47%) increased toward the center of the disc but did not differ between the sides of the IVDs. The fibrils found in the outer AF on the convex side were 30% thinner. CONCLUSION: This study was able to show significant differences in cell morphologies in the AF on both sides and in correlation to the different tilt angles. The type and magnitude of load seem to influence disc cells. Further studies are required to provide more information on disc and cell changes in scoliosis.

The impact of a distal expansion mechanism added to a standard pedicle screw on pullout resistance. A biomechanical study.

BACKGROUND CONTEXT: Spinal deformity surgery in elderly patients is associated with an increased risk of implant loosening due to failure at the screw-bone interface. Several techniques can be used to increase the screw anchorage characteristics. Cement-augmented screw fixation was shown to be the most efficient method; however, this technique is associated with a risk of complications related to vertebral cement deposition and leakage. Hence, there is a need to further elaborate the alternative screw augmenting techniques to reduce the indications for bone cement. PURPOSE: To analyze surgical alternatives to cement augmentation, the present study sought to quantify the impact of a distal expansion mechanism added to a standard pedicle screw on an axial pullout resistance. STUDY DESIGN: A biomechanical laboratory study on the uniaxial pullout resistance of a standard pedicle screw versus a customized pedicle screw with a distal expansion mechanism. METHODS: A total of 40 vertebrae from seven fresh-frozen human specimens were harvested and subjected to a computed tomography scanning and an analysis of the bone mineral density (BMD). The vertebrae were instrumented with a standard 6.0-mm pedicle screw and a modified 6.0-mm pedicle screw with a distal expansion mechanism added. The actual working length of both screws inside the vertebrae was identical. The distal expansion mechanism made up one-fifth of the shaft length. The accuracy of the screw insertion was assessed using biplanar radiographs and by inspection. Analysis of resistance to pullout was performed by a coaxial alignment of the pedicle screws and attachment to an electromechanical testing machine. The pullout rate was 5 mm/min, and the load-displacement curve was recorded until the force of the pullout resistance peaked. The peak load-to-failure was measured in Newtons and reported as the ultimate failure load. With each test, the mode of failure was noted and analyzed descriptively. RESULTS: A total of 17 vertebrae with matched pairs of standard and expansion pedicle screws were eligible for the final statistical analysis. The BMD of the vertebrae tested was 0.67±0.19 g/cm³. The screw length was 50 mm, and the actual working length of both screws was 40.3±4.2 mm. The ultimate failure load of the standard screw was 773.8±529.4 N and that of the expansion screw was 910.3±488.3 N. Statistical analysis revealed a strong trend toward an increased failure load with the expansion screw (p=.06). The mean increase of the ultimate failure load was 136.5±350.4 N. Abrupt vertebral fracture at the vertebral body-pedicle junction and the pedicle occurred seven times with the expansion screw and only five times with the standard screw (p=.16). CONCLUSIONS: Our study indicates that adding a distal expansion mechanism to a standard pedicle screw increases the failure load by one-fifth. Modern expansion screws might offer an intermediate solution for the augmentation of screw-rod constructs in osteoporotic bone while reducing the need for cement-augmented screws and avoiding the related risks.

In vivo analysis of cervical kinematics after implantation of a minimally constrained cervical artificial disc replacement.

INTRODUCTION: To better understand cervical kinematics following cervical disc replacement (CDR), the in vivo behavior of a minimally constrained CDR was assessed. METHODS: Radiographic analysis of 19 patients undergoing a 1-level CDR from C4-5 to C6-7 (DISCOVER, Depuy-Spine, USA) was performed. Neutral-lateral and flexion-extension radiographs obtained at preop, postop and late follow-up were analyzed for segmental angle and global angle (GA C2-7). Flexion-extension range of motion was analyzed using validated quantitative motion analysis software (QMA®, Medical Metrics, USA). The FSU motion parameters measured at the index and adjacent levels were angular range of motion (ROM), translation and center of rotation (COR). Translation and COR were normalized to the AP dimension of the inferior endplate of the caudal vertebra. All motion parameters, including COR, were compared with normative reference data. RESULTS: The average patient age was 43.5 ± 7.3 years. The mean follow-up was 15.3 ± 7.2 months. C2-7 ROM was 35.9° ± 15.7° at preop and 45.4° ± 13.6° at follow-up (∆p < .01). Based on the QMA at follow-up, angular ROM at the CDR level measured 9.8° ± 5.9° and translation was 10.1 ± 7.8 %. Individuals with higher ROM at the CDR level had increased translation at that level (p < .001, r = 0.97), increased translation and ROM at the supra-adjacent level (p < .001, r = .8; p = .005, r = .6). There was a strong interrelation between angular ROM and translation at the supra-adjacent level (p < .001, r = .9) and caudal-adjacent level (p < .001, r = .9). The location of the COR at the CDR- and supra-adjacent levels was significantly different for the COR-X (p < .001). Notably, the COR-Y at the CDR level was significantly correlated with the extent of CDR-level translation (p = .02, r = .6). Shell angle, which may be influenced by implant size and positioning had no impact on angular ROM but was correlated with COR-X (p = .05, r = -.6) and COR-Y (p = .04, r = -.5). CONCLUSION: The COR is an important parameter for assessing the ability of non-constrained CDRs to replicate the normal kinematics of a FSU. CDR size and location, both of which can impact shell angle, may influence the amount of translation by affecting the location of the COR. Future research is needed to show how much translation is beneficial concerning clinical outcomes and facet loading.

Non-instrumented correction of cervicothoracic kyphosis in ankylosing spondylitis: a critical analysis on the results of open-wedge osteotomy C7-T1 with gradual Halo-Thoracic-Cast based correction.

INTRODUCTION: With progression of cervicothoracic kyphosis (CTK), ankylosing spondylitis (AS) patients suffer functional disability. Surgical correction still poses neurologic risks, while evidence of an ideal technique preventing its complications is weak. MATERIALS AND METHODS: We report our results with non-instrumented correction in perspective of a review of literature, serving as an important historical control. Database review identified 18 AS patients with CTK correction. After application of a Halo-Thoracic-Cast (HTC) patients underwent posterior non-instrumented open-wedge osteotomy at C7/T1 and osteotomy closure by threaded HTC-rod adjustments. Postoperative gradual HTC correction was continued for 2-4 weeks. Patients were invited for follow-up and medical charts were reviewed for demographics, surgical details, complications and outcomes. The patients' preoperative, postoperative, before HTC removal and follow-up photographs were analyzed for the Chin-Brow-Vertical-Angle (CBVA), radiographs for the CTK angle. RESULTS: Patients' age was 50 ± 11 years, follow-up was 37 ± 47 months and CBVA correction was 25° ± 9° (p < 0.000001). The final radiographic correction at follow-up was 20° ± 11° (p = 0.00002). At the latest follow-up, three patients judged their outcome as excellent, nine good, three moderate and one poor. Upon invitation, seven patients appeared with follow-up averaging 87 months. Neck-pain disability index was 8 ± 14 %. Two patients died, three were lost, one had revision elsewhere and five just had a routine follow-up. Six patients sustained a minor and ten a major complication. Revisions were indicated in five patients including infection, C8-radiculopathy and neurologic events by translation at the osteotomy. A total of 44 % of patients showed translation at the osteotomy indicating acute surgery with instrumentation twice after osteotomy closure, three patients had a revision posterior decompression and instrumented fusion for sequels related to translation. CONCLUSION: With the non-instrumented HTC-based technique, average CBVA correction of 25° was achieved and all patients were ambulatory at follow-up. However, regarding translation at the osteotomy, loss of correction, morbidity of the HTC and lack of control at the osteotomy instrumentation-based correction and instrumented fusion seem to be preferable.