Relationship between iliac screw loosening and proximal junctional kyphosis after long thoracolumbar instrumented fusion for adult spinal deformity

European Spine Journal - Authors assumed that the stability of iliac screw (IS) fixation could affect the development of proximal junctional kyphosis (PJK). The purpose of this study was to analyze...     

Osteoporosis increases the likelihood of revision surgery following a long spinal fusion for adult spinal deformity

BACKGROUNDAdult spinal deformity (ASD) can be a debilitating condition that requires surgical intervention. ASD patients often present with osteoporosis, predisposing them to increased rates of instrumentation failure and postoperative fractures, frequent reasons for revision surgery. We hypothesized that the rate and timing of revision surgery are different in osteoporotic and nonosteoporotic patients undergoing long fusions for ASD. To our knowledge, the timing of revision surgeries, in particular, have not previously been explored.PURPOSETo determine the rate and timing of revision surgery in osteoporotic and nonosteoporotic patients following a long fusion for ASD.STUDY DESIGNRetrospective comparative study.PATIENT SAMPLEASD patients who underwent a long spinal fusion surgery at two large academic medical centers from 2010 to 2019.OUTCOME MEASURESOccurrence of revision surgery.METHODSInclusion criteria were patient age of least 40 years and spinal fusion spanning at least seven levels for ASD. Patient records were reviewed for a diagnosis of osteoporosis as per ICD codes and revision surgery within 2 years of the index procedure. Revision surgery was defined as an unplanned procedure related to the index surgery for the treatment of a spine-related complication. Chi-squared tests comparing demographic data, revision rates, and multiple revisions were conducted. The incidence and prevalence of revision surgeries as a function of time and osteoporotic status were evaluated for significant differences via the Mann-Whitney U and Mantel-Haenszel log rank tests. Finally, a logistic regression analysis was utilized to determine the predictive value of osteoporosis, age, and gender on the likelihood for complications.RESULTSThree hundred ninety-nine patients matched the study criteria. In the osteoporotic group, 40.5% of patients underwent a revision surgery compared to 28.0% in the nonosteoporotic group (p=.01). The occurrence of multiple revision surgeries following the index procedure was similar in both groups: 8.4% in osteoporotic patients and 8.6% in nonosteoporotic patients. Age and gender were not statistically correlated with the incidence of revision surgery.CONCLUSIONSASD patients with osteoporosis have an increased risk of undergoing revision for a surgery-related complication within 2 years of the index procedure. These complications included failure of hardware, pseudoarthrosis, proximal junction failure, and infection, among other issues that required surgical intervention. As others have also highlighted the importance of poor bone density on construct failure, our data further underscore the importance of preoperative osteoporosis surveillance. Though intuitive, further study is needed to demonstrate that improving patients’ bone density can decrease the incidence of related complications and the need or revision surgery.     

Treatment of adult spinal deformity with fusion to the sacrum using CD instrumentation.

The effectiveness of Cotrel-Dubousset (CD) instrumentation in long fusions to the sacrum for adult spinal deformity was evaluated in 27 consecutive patients. The CD system provided acceptable correction of kyphosis and scoliosis while restoring or maintaining lumbar lordosis. However, the standard CD pelvic fixation using sacral pedicle and alar screws was problematic. Instrumentation-related complications were frequent (70%). Sagittal and frontal plane balance was difficult to achieve and not consistently maintained. The CD system using sacral pedicle and alar screws in the adult patient does not appear to offer advantages over alternative techniques for achieving arthrodesis to the sacrum for adult deformity.     

后路全脊柱截骨与重建矫正胸腰椎骨折手术失败后后凸畸形

胸腰椎骨折临床多见且呈上升趋势,其中有神经症状和脊柱不稳者需要手术治疗,绝大多数手术效果良好,但仍然有部分手术失败造成脊柱后突畸形,甚至严重畸形.     

Significance of long corrective fusion to the ilium for physical function in patients with adult spinal deformity

BackgroundWe aimed to investigate the impact of long corrective fusion to the ilium on the physical function in elderly patients with adult spinal deformity and its correlation with spinopelvic parameters and health-related quality of life outcomes.MethodsWe included 60 female patients who underwent long corrective fusion from T9 or T10 to the pelvis for adult spinal deformities (mean age of 69.8 years, range 55–78 years). The radiographic parameters, health-related quality of life outcomes using the Scoliosis Research Society Outcome Instrument-22 and physical function assessments were reviewed preoperatively and at 1-year postoperatively.ResultsAll spinopelvic parameters, except for thoracolumbar kyphosis, and all domains of the Scoliosis Research Society Outcome Instrument-22 significantly improved at 1-year postoperatively (p < 0.0001). Physical function results, including those for one-leg standing time, timed up-and-go test, and 6-min walk tests, significantly improved at 1-year postoperatively (p < 0.005). Based on forward stepwise multivariate logistic regression, the predicted timed up-and-go test and 6-min walk test outcomes at 1-year postoperatively were as follows: timed up-and-go test, 7.8 + 0.47 × preoperative timed up-and-go test – 0.21 × 1-year postoperative grasping power +0.015 × 1-year postoperative C1 sagittal vertical axis (R2 = 0.6209, p < 0.0001); 6-min walk test, 309.2–9.1 × body mass index + 11.6 × 1-year postoperative grasping power + 3.3 × 1-year postoperative thoracolumbar kyphosis – 0.59 × 1-year postoperative C1 sagittal vertical axis (R2 = 0.4409, p < 0.0001).ConclusionsCorrective long fusion surgery for adult spinal deformity in normalizing sagittal alignment improves trunk balance and gait performance. Postoperative physical function depends on the preoperative physical performance status and skeletal muscle status; thus, preoperative interventions for improved physical function are recommended.     

成人脊柱畸形远端融合椎的选择问题

<正>成人脊柱畸形(adult spinal deformity,ASD)治疗目标是缓解腰背痛、去除神经压迫、恢复脊柱平衡和改善生活质量。手术方式中融合节段尤其是远端融合椎的选择,由于涉及到术后近、远期疗效问题,引起了学者们的广泛关注。ASD远端融合椎终止于L5、S1还是髂骨,既有共识,亦存有争议,结合文献和自身经验,浅谈一些体会与思考。     

Treatment of scoliosis in the adult thoracolumbar spine with special reference to fusion to the sacrum

The major indication for operative intervention in adults with lumbar and thoracolumbar curves is pain. A careful analysis of the pain, including a careful history and the use of discography and facet blocks, has greatly enhanced the success rate both in terms of correction and relief of symptoms postoperatively. Zielke instrumentation is the preferred surgical technique for thoracolumbar curves that do not require extension of the fusion to the sacrum. Cotrel-Dubousset fixation is particularly advocated in those cases that show evidence of spinal stenosis and require posterior decompression or in cases of rigid kyphoscoliosis following an anterior release. Fusions of the sacrum require a combined anterior and posterior approach. Iatrogenic loss of lumbar lordosis can be prevented by careful attention to detail and posterior instrumentation with preservation of lumbar lordosis, contouring of rods, and hyperextension of spine and hips at the time of surgery. Loss of lumbar lordosis, which may result in marked fatigue and pain as well as a deformity often worse than the initial one, can be corrected, preferably by a combined anterior and posterior approach (Fig. 5).     

后路长节段固定治疗成人退行性脊柱畸形的疗效及其远端并发症

目的 :探讨后路长节段固定治疗成人退行性脊柱畸形的效果以及远端并发症的发生率。方法 :回顾性分析2010年1月~2015年1月在我院接受一期后路长节段椎弓根螺钉固定矫形治疗的成人脊柱畸形患者,病例入选标准:(1)诊断为成人退行性脊柱畸形;(2)年龄超过50岁;(3)影像学满足冠状面Cobb角度20°,或者矢状面平衡(SVA)5cm;(4)后方腰椎固定融合在4个节段以上;(5)随访时间在12个月以上。分析患者的人口学特点、影像学参数、健康相关生活质量评分和远端并发症等资料。结果:共纳入74例患者,其中远端固定椎在L5的患者43例(L5组),固定在S1的患者22例(S1组),固定到髂骨的患者9例(髂骨组)。随访12~64个月,平均28.8个月,三组患者术后冠状面Cobb角、冠状面平衡(CSVL)、矢状面平衡(SVA)、PI-LL、PT角度与术前比较均有显著性改善(P0.05)。术后健康相关生活质量评分(ODI和SF-12 PCS)与术前相比均得到明显改善(P0.05)。远端并发症总的发生率为29.7%(22/74),保留L5/S1椎间盘患者远端并发症的发生率显著性高于L5/S1融合的患者(39.5%vs 16.1%),保留L5/S1椎间盘是远端并发症的独立危险因素(P=0.03)。结论:长节段固定融合治疗成人退行性脊柱畸形能够改善患者的健康相关生活质量评分,获得满意的临床效果;保留L5/S1椎间盘发生远端并发症的风险更高。     

Obesity negatively affects cost efficiency and outcomes following adult spinal deformity surgery

BACKGROUND CONTEXTObesity has risen to epidemic proportions within the United States. As the rates of obesity have increased, so has its prevalence among patients undergoing adult spinal deformity (ASD) surgery. The effect of obesity on the cost efficiency of corrective procedures for ASD has not been effectively evaluated.PURPOSETo investigate differences in cost efficiency of ASD surgery for patients stratified by body mass index (BMI).STUDY DESIGN/SETTINGRetrospective review of a single-center ASD database.PATIENT SAMPLEFive hundred five ASD patients.OUTCOME MEASURESComplications, revisions, costs, EuroQol-5D (EQ5D), quality-adjusted life years (QALYs), cost per QALY.METHODSASD patients (scoliosis≥20°, SVA≥5 cm, PT≥25°, or TK ≥60°) ≥18, undergoing ≥4 level fusions were included. Patients were stratified into NIH-defined obesity groups based on their preoperative BMI: underweight 18.5< (U), normal 18.5 to 24.9 (N), overweight 25.0 to 29.9 (O), obese I 30.0 to 34.9 (OI), obese II 35.0 to 39.9 (OII), and obesity class III 40.0+ (OIII). Total surgery costs for each ASD obesity group were calculated. Costs were calculated using the PearlDiver database, which reflects both private insurance and Medicare reimbursement claims. Overall complications and major complications were assessed according to CMS definitions. QALYs and cost per QALY for obesity groups were calculated using an annual 3% discount up to life expectancy (78.7 years).RESULTSIn all, 505 patients met inclusion criteria. Baseline demographics and surgical details were: age 60.8±14.8, 67.6% female, BMI 28.8±7.30, 81.0% posterior approach, 18% combined approach, 10.1±4.2 levels fused, op time 441.2±146.1 minutes, EBL 1903.8±1594.7 cc, and LOS 8.7±10.7 days. There were 17 U, 154 N patients, 151 O patients, 100 OI, 51 OII, and 32 OIII patients. Revision rates by obesity group were: 0% U, 3% N patients, 3% O patients, 5% OI, 4% OII, and 6% for OIII patients. The total surgery costs by obesity group were: $48,757.86 U, $49,688.52 N, $47,219.93 O, $50,467.66 OI, $51,189.47 OII, and $53,855.79 OIII. In an analysis of patients with baseline and 1 Y EQ5D follow-up, the cost per QALY by obesity group was: $153,737.78 U, $229,222.37 N, $290,361.68 O, $493,588.47 OI, $327,876.21 OII, and $171,680.00 OIII. If that benefit was sustained to life expectancy, the cost per QALY was $8,588.70 U, $12,805.72 N, $16,221.32 O, $27,574.77 OI, $18,317.11 OII, and $9,591.06 for OIII.CONCLUSIONSAmong adult spinal deformity patients, those with BMIs in the obesity I, obesity II, or obesity class III range had more expensive total surgery costs. When assessing 1 year cost per QALY, obese patients had costs 32% higher than nonobese patients ($224,440.61 vs. $331,048.23). Further research is warranted on the utility of optimizing modifiable preoperative health factors for patients undergoing corrective adult spinal deformity surgery.     

Long fusions to the sacrum in elderly patients with spinal deformity

Purpose

Long spinal deformity fusions in elderly patients continue to be controversial. However, there is a growing population of elderly patients with spinal deformities that may be optimally treated by reconstructive surgery requiring a long fusion to the sacrum. This study evaluated clinical outcomes in elderly (>65) adult deformity patients who underwent posterior instrumented reconstruction consisting of fusion from the thoracic spine to the sacrum with iliac fixation.

Methods

Patients in a prospective database for adult spinal deformity who had a posterior reconstruction with an instrumented fusion from the thoracic spine to the sacrum that included iliac fixation with minimum 2-year follow-up were identified. Two cohorts were compared: patients 65 years and older and patients 55 years and younger. Student’s t test for independent groups was used to determine any significant differences between continuous variables. Chi-square was used to compare categorical demographic variables between the two groups.

Results

The 65 and older group consisted of 15 patients with an average age of 71 years (range 65–78 years). The 55 and younger group consisted of 25 patients with an average age of 45 years (range 30–55 years). The older group had a worse mean co-morbidity score (4.6 vs. 2.1). Baseline SRS scores were similar between groups. Baseline SF-12 data showed worse PCS (22.1 vs. 32.0, p = 0.009) yet better MCS (63.6 vs. 48.4, p < 0.0001) in the older group. Although major curve magnitude was similar (47.1° vs. 42.6°), the older group had more positive sagittal imbalance at baseline (115.7 vs. 54.2 mm, p = 0.02). Number of levels fused, operative time, blood loss, and incidence of complications were similar between groups. Two-year improvements in SRS subscores, SF-12 PCS, and MCS were not significantly different between groups.

Conclusions

Properly selected patients 65 years of age and older who have substantial sagittal imbalance, a considerable disease burden, and a lesser degree of mental distress can obtain as much clinical benefit as their younger counterparts (≤55 years of age) 2 years following spinal deformity surgery that requires fusion from the thoracic spine to the sacrum with segmental instrumentation and iliac fixation.     

Rod fracture after long construct fusion in adult spinal deformity surgery: A retrospective case-control study

BackgroundVery few studies have focused on the complication of rod fracture after posterior long construct fusion in adults with spinal deformity. Therefore, this retrospective study aimed to investigate the incidence and risk factors of this complication.MethodsThe study reviewed 213 adult patients with spinal deformity treated by long construct fusion between January 2009 and January 2017. Ten patients (4.6%) with rod fracture were included in the case study group. For each case of rod fracture, we selected two age-matched and gender-matched controls. Independent two-sample t test and Chi-square test were used to compare the differences between variables. Binary logistic regression analysis was performed to identify independent risk factors of rod fracture.ResultsStatistically significant differences were observed between the groups, in terms of additional bone grafts volume (P = 0.015), osteotomy (P = 0.017), skipped screw in sagittal apex region (P = 0.012), TK change (P = 0.023), and preoperative TLK (P = 0.036). However, there were no differences in terms of age (P = 0.933), follow-up time (P = 0.513), gender distribution (P = 0.650), fusion segments (P = 0.085), the number of screws (P = 0.131), density of screws (P = 0.088), preoperative MC (P = 0.120), postoperative MC (P = 0.430), MC change (P = 0.126), preoperative TK (P = 0.590), postoperative TLK (P = 0.074), TLK change (P = 0.064), preoperative LL (P = 0.084), postoperative LL (P = 0.065), and LL change (P = 0.914). Binary logistic regression analysis revealed that osteotomy (P = 0.023) and skipped screw strategy in sagittal apex region (P = 0.046) were the primary factors included in the equation [Odds Ratio (OR) = 11.669 and 7.659, respectively].ConclusionIn our study, the prevalence of rod fracture in adult patients with spinal deformity after long construct fusion was 4.6%; osteotomy was the main risk factor of rod fracture these patients. The skipped screws in sagittal apex region could increase the risk of rod fracture because the stress on the rods failed to be distributed to different segments.     

Morbidity following isolated fractures of the sacrum

There is little information in the orthopaedic literature on the long-term results following isolated fractures of the sacrum. The present study traced patients with these fractures, and attempted to identify the incidence of long-term symptoms. The study revealed that isolated fractures of the sacrum are not always benign, and may result in chronic discomfort (sacrodynia) or persistent neurological symptoms.     

胸腰椎骨折三点加压固定中哈灵顿棒危险断面及其载荷影响的研究

本文采用二维光弹模型研究哈灵顿分离棒（ＨＤＲ）的应力分布。实验载荷包括作用于两端钩部的垂直力及作用于棒中点的水平力。实验发现棒棘齿区应力高于光滑区，ＨＤＲ光滑区—棘齿区交界处应力居棒同侧最高，是棒强度的危险断面，其应力值与载荷呈正直线相关．本文亦初步讨论了减少危险断面应力、避免ＨＤＲ疲劳断裂的途径。     

Hidden blood loss in extreme lateral interbody fusion for adult spinal deformity

BackgroundExtreme lateral interbody fusion (XLIF) is often used with posterior spinal fixation (PSF) to treat adult spinal deformity (ASD). However, the amount of intraoperative blood loss (IBL) reported for XLIF may underestimate the total blood loss (TBL). The objective of this study was to determine the total perioperative blood loss in XLIF for ASD.MethodsWe assessed 30 consecutive ASD patients with Schwab-SRS type L (mean age: 68.7 ± 8.2 years; mean follow-up 2.0 ± 1.3 years) who were treated by multilevel XLIF (mean, 2.5 ± 0.6 levels) followed by PSF after 3–5 days. We calculated the TBL after XLIF by the Gross equation, by hemoglobin (Hb) balance, and by the Orthopedic Surgery Transfusion Hemoglobin European Overview (OSTHEO) formula. We defined hidden blood loss (HBL) as the difference between the TBL and IBL. Pearson correlation, Spearman correlation, and multiple logistic regression analysis were performed to investigate the risk factors related to HBL.ResultsPost-XLIF blood tests showed a significant decrease in the Hb (from 11.8 ± 1.1 mg/dl to 10.6 ± 1.1 mg/dl) and hematocrit (from 36.0 ± 3.2% to 32.5 ± 3.2%). Although the mean IBL was relatively small (33 ± 52 mL), we calculated the TBL as 291 ± 171 mL (Gross equation) and the HBL as 258 ± 168 mL by Gross equation, which was 8 times greater than the IBL on average. There was no difference in the results obtained using the three methods. Multiple logistic regression analysis indicated preoperative lumber lordosis was the risk factor of high HBL (Odds ratio = 1.085, 95%CI: 1.006–1.170, p = 0.035).ConclusionsThe HBL in XLIF was 8 times greater than the IBL. During the perioperative course of correction and fusion surgery for ASD with XLIF, surgeons need to pay attention not to underestimate the TBL.     

Complications and results of long adult deformity fusions down to l4, l5, and the sacrum

STUDY DESIGN: This is a consecutive study of patients having undergone surgical treatment of adult lumbar scoliosis. Follow-up ranged from 2 to 13 years (average 5 years). OBJECTIVES: To assess the complications and outcomes of patients with long fusions to L4 (n=23), L5 (n=21), or the sacrum (n=15) and determine if a "deeply seated" L5 segment is protective. SUMMARY OF BACKGROUND DATA: Few studies assess outcomes and complications in adults fused from the thoracic spine to L4, L5, or the sacrum with minimum 2-year follow-up. METHODS: Fifty-eight patients (59 cases; average age 43 years; range 21 to 60) with minimum 2-year follow-up were analyzed for subsequent spinal degeneration and complications. Outcomes were assessed from questionnaires administered at latest follow-up. RESULTS: Sixteen percent of cases (7 of 44) fused short of the sacrum displayed subsequent postoperative distal spinal degeneration, although only three patients were symptomatic. Compared with the group with no subsequent degeneration, this group had a lower improvement in function and pain relief. Other complications for patients fused short of the sacrum included two cases with crosslink breakage, one with neurologic deficit, three with pseudarthroses, one with hook pullout, and one with L5 screw pullout. For cases fused to the sacrum, two cases with deep wound infections and one with loose iliac screw requiring removal were observed. Because two of four cases fused to L5 with subsequent degeneration at L5-S1 were observed to have "deeply seated" L5 segments and two of the four did not, the authors could conclude only that "deep seating" of L5 is not absolute protection. CONCLUSIONS: Fusions short of the sacrum did not have predictable long-term results. Those fused short of the sacrum who developed distal spinal degeneration had worse outcomes. Patients fused to the sacrum did not have a higher complication rate. A "deeply seated" L5 segment does not necessarily protect the L5-S1 disc.     

Preoperative gait comparisons between adults undergoing long spinal deformity fusion surgery (thoracic to L4, L5, or sacrum) and controls

STUDY DESIGN: This investigation compared the gait of revision and primary spinal deformity patients about to undergo surgical reconstruction with that of a group of able-bodied controls. OBJECTIVES: The hypothesis of the study was that both patient groups would have significantly compromised gait, spine motion, and gait endurance compared with the able-bodied group. SUMMARY OF BACKGROUND DATA: There is a population of adults with degenerative changes superimposed on idiopathic scoliosis who present for reconstructive spinal surgery (primary patients). There is another group of adults who have already had spinal deformity surgery and present for revision surgery (revision patients). METHODS: Twenty-seven women were recruited (8 primary, 13 revision, 6 able-bodied controls). A typical gait analysis was performed. Walking endurance was estimated from a submaximal graded treadmill exercise test. Three motion variables describing the orientation of the shoulders with respect to the pelvis in the three principal planes of the body were determined. Also, gait speed, stride length, cadence, and step width were calculated. The variable for the endurance test was the length of time walked on the treadmill. RESULTS: Results for the revision group indicated a slower walking speed, greater sagittal plane trunk flexion, reduced range of motion in the coronal and transverse planes, and poorer endurance relative to age-matched controls. The primary group demonstrated a slower walking speed relative to age-matched controls. The revision group had poorer endurance scores relative to the primary group. CONCLUSION: This investigation is an objective report describing the compromised gait and walking endurance of adult patients with spinal deformity before spinal fusion surgery. Results supported subjective observations regarding the preoperative gait of these patients and presented results difficult to observe in a clinical setting. The techniques appear useful in providing objective information regarding the gait abilities of these patients.