Peri-operative optimization in adult spinal deformity surgery

The population aged 65 and over is projected to double by the year 2050. As the population continues to age, the incidence of adult spinal deformity (ASD) will continue to rise. It is estimated that 30–50% of patients older than 65-years develop a degenerative scoliosis. Many of these patients have little to no symptoms as a result of their deformity and continue to lead active and healthy lives. A smaller subset of patients with degenerative scoliosis develops pain and disability as a result of their underlying deformity. The outcomes of surgery in this group are generally favorable but there is significant risk and potential morbidity associated with deformity correction surgery. The pre-operative planning and technical aspects of surgery are important but the peri-operative optimization of modifiable factors to minimize the risk of complications is even more important to achieve optimal outcomes. This paper will review the most up-to-date literature on the peri-operative optimization of patients undergoing adult spinal deformity surgery.     

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.     

Age-adjusted alignment goals in adult spinal deformity surgery

Adult spinal deformity causes pain, disability, and alterations in the quality of life of patients. Sagittal alignment and spinopelvic parameters have been established to provide surgeons with correction goals based upon normative population values. Recently, much research has been done to optimize patient outcomes regarding these parameters and at the same time reduce complications such as proximal junction kyphosis. Recently, there has been growing interest in tailoring these alignment goals based on patient age, with an overall intention of achieving a less substantial correction in older patients compared to traditional alignment goals used for younger populations. This review paper will provide a framework of understanding how advanced age impacts the sagittal alignment of the spine, the evidence supporting age-adjusted alignment goals, and also shortcomings and areas for future investigation.     

Revision surgery for non-union in adult spinal deformity

As adult spinal deformity surgery is performed more and more, the spine surgeon is faced with the challenge to treat pseudoarthrosis. The presentation may vary, from asymptomatic patients, who should be observed in most of the cases, to patients with acute episode of broken rods, and or chronic pain with often trunk imbalance. In some instances, patients will present with neurologic symptoms. The evaluation of such patients must start with a good understanding of why the surgery failed first place. Poor host, smoking, lack of anterior column support, poor sagittal balance, lack of fusion, poor construct. Often a combination of all of the above is encountered. The workup for such cases consists of imaging studies (with often a CT myelogram as the excessive metal artifact will render the MRI imaging useless), nutrition labs, DEXA scan, EOS films and internal medicine or cardiology consult for risk stratification as this may represent major surgery. Indication of surgery is mostly based on pain and imbalance and/or poor function. The surgeon planning a revision adult deformity surgery has many tasks to perform: Identify and avoid the reasons that lead to failure of the previous surgeries. Plan the anterior column reconstruction either through posterior or anterior interbody fusion. Restore the global alignment through anterior or posterior osteotomies to achieve sagittal and coronal balance. Obtain a solid fixation with sufficient levels above and below the osteotomies sites with in some cases the use of pelvic screws and four rods (Quad-Rod) techniques. The use of bone graft (either autologous, allograft, bone graft enhancers and inducer) agents. The requirement of decompression either through a virgin spine or a previous laminectomy bed. Despite the extent of these surgeries and the potential for immediate postoperative complications, the outcome is in most cases satisfactory if these goals are achieved. In this review, the authors explore different scenarios for pseudoarthrosis in the adult spine deformity patient and the preferred treatment method to obtain the best outcome for every individual patient. These slides can be retrieved under Electronic Supplementary Material.     

Proximal junctional kyphosis following adult spinal deformity surgery

Purpose

Proximal junctional kyphosis (PJK) is a common radiographic finding following long spinal fusions. Whether PJK leads to negative clinical outcome is currently debatable. A systematic review was performed to assess the prevalence, risk factors, and treatments of PJK.

Methods

Literature search was conducted on PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials using the terms ‘proximal junctional kyphosis’ and ‘proximal junctional failure’. Excluding reviews, commentaries, and case reports, we analyzed 33 studies that reported the prevalence rate, risk factors, and discussions on PJK following spinal deformity surgery.

Results

The prevalence rates varied widely from 6 to 61.7 %. Numerous studies reported that clinical outcomes for patients with PJK were not significantly different from those without, except in one recent study in which adult patients with PJK experienced more pain. Risk factors for PJK included age at operation, low bone mineral density, shorter fusion constructs, upper instrumented vertebrae below L2, and inadequate restoration of global sagittal balance.

Conclusions

Prevalence of PJK following long spinal fusion for adult spinal deformity was high but not clinically significant. Careful and detailed preoperative planning and surgical execution may reduce PJK in adult spinal deformity patients.     

Outcomes and cost-effectiveness of adult spinal deformity surgery

Adult spinal deformity is a debilitating disease affecting multiple aspects of patients’ lives including mental and physical well-being and functional ability. Advances in our understanding of the deformities and operative techniques have led to large improvements in patient reported outcomes, even with the associated high rate of complications. As we transition into the era of value-based care, the relatively high cost of deformity surgery has come under increasing scrutiny. Additional investigation of the costs of deformity surgery are required in order to employ effective cost-control measures while continuing to provide high-level care.     

Revision strategies for failed adult spinal deformity surgery

The aim of this study is to analyse the results of revision surgery for failed adult spinal deformity patients and to describe the surgical strategy selection process, based on the identification of the main clinical diagnosis responsible for failure. We retrospectively reviewed the clinical and radiological data of 77 consecutive patients treated in a 3-year time (2016–2019) for surgical revision of long fusion (more than five levels fused) for adult spinal deformity in a high-volume spine centre, divided into four groups based on the diagnosis: rod breakage (RB) group, proximal junctional failure (PJF) group, distal junctional failure (DJF) group and loss of correction (LOC) group with symptomatic sagittal or coronal malalignment (including iatrogenic flatback). Seventy-seven patients met our inclusion criteria, with a female prevalence (66 F vs. 11 M). The mean age at revision surgery was 63. Fused levels before surgery were averagely 12, and revision added averagely two levels to the preexisting fusion area. Clinical status was apparently improved in ODI scores and VAS scores, while it was slightly worsened in SF36 scores. Different diagnosis groups have been addressed with different surgical strategies, according to the different surgical goals: interbody cages and multi-rod construct to improve stiffness and favour bony fusion, “kickstand” rod and “tie” rod to correct coronal and sagittal malalignment, specific rod contouring and proximal hooks in “claw” configuration to reduce mechanical stress at the proximal junctional area. Intraoperative complications occurred in 18% of patients and perioperative complications in 39%. Revision surgery in long fusions for adult spinal deformity is a challenging field. Surgical strategy should always be planned carefully. A successful treatment is a direct consequence of a correct preoperative diagnosis, and surgery should address the primary cause of failure. All the above-mentioned surgical techniques and clinical skills should be part of surgeon’s expertise when managing these patients. These slides can be retrieved under Electronic Supplementary Material.     

Risk factors for nonroutine discharge in adult spinal deformity surgery

BACKGROUND CONTEXTSurgery for adult spinal deformity (ASD) is increasingly common. Although outcomes of ASD surgery have been studied extensively, to our knowledge, no data exist regarding factors predicting nonroutine discharge in this population. Nonroutine discharge is defined as discharge to a health care facility after surgery rather than to home.PURPOSETo determine which patient and surgical factors predict nonroutine discharge after ASD surgery.DESIGNThis is a retrospective study.PATIENTS SAMPLEWe conducted a retrospective single-center study of 303 patients who underwent arthrodesis of five or more spinal levels to treat ASD between 2009 and 2014.OUTCOME MEASURESPatients were stratified into two groups according to discharge disposition: home or nonroutine.METHODSObjective preoperative characteristics, intraoperative course, and postoperative recovery were analyzed to identify pre- and perioperative factors associated with nonroutine discharge. Univariate analysis was performed first. All factors with P values < .2 on univariate analysis were included in a logistic regression model. Additionally, to understand the relationship between subjective patient-reported outcome measures and nonroutine discharge, we compared the two groups with respect to mean Oswestry Disability Index and Scoliosis Research Society-22r domains using Student t-tests.RESULTSOn univariate analysis, objective measures that differed significantly (P < .05) between the two cohorts were age (≥65 years), osteoporosis, Charlson Comorbidity Index score of ≥2, prolonged hospital stay (>8 days), and blood transfusion. Given the above logistic regression inclusion criteria, we controlled for the performance, and type, of osteotomy (P = .055). On multivariate analysis, older age, osteoporosis, prolonged hospital stay, blood transfusion, and 3-column osteotomy were independently associated with nonroutine discharge. Subjective patient-reported outcome measures, including Oswestry Disability Index and Scoliosis Research Society-22r physical function and pain domain scores, were significantly worse in the nonroutine discharge cohort (P < .05).CONCLUSIONTo our knowledge, this is the first study to evaluate pre- and perioperative factors associated with nonroutine discharge after ASD surgery. Elderly patients who undergo complex surgery and receive blood transfusions are at particularly high risk of nonroutine discharge. Surgeons should consider these factors during surgical planning and preoperative patient counseling.     

Measuring outcomes in spinal deformity

The development of validated health-related quality-of-life instruments that are generic (Short Form-36) or disease-specific (Scoliosis Research Society [SRS]-22) allows physicians and researchers to measure the qualitative impact of spinal deformity and its treatment on their patients quantitatively. Although some further research may be needed in the area of the responsiveness of the SRS-22r, it should be considered a validated instrument that is useful in the research and treatment of pediatric and adult patients with spinal deformity.     

Do 1-year outcomes predict 2-year outcomes for adult deformity surgery?

Background ContextHealth-related quality-of-life (HRQOL) measures are being used more frequently in the evaluation of the adult deformity patient. This is due in part to the validation of the deformity-specific Scolios Research Society-22 (SRS-22). Hence, relationships between HRQOL outcomes and traditional measures of success such as deformity correction, fusion healing, and complications are being established.PurposeTo examine the pattern of HRQOL outcome responses after adult deformity surgery.Study designAnalysis of prospective multicenter cohort.Patient sampleTwo hundred and eighty-three adult deformity patients with preoperative, 1-, and 2-year postoperative outcome measures.Outcome measuresSRS-22, Short Form-12 (SF-12), Oswestry Disability Index (ODI), and back and leg pain numeric rating scale scores.MethodsPreoperative versus postoperative health status measures were evaluated by matched-pairs sample t test statistics and post hoc analysis of variance (ANOVA) findings.ResultsSRS-22 improved from a mean 3.03 points at baseline to 3.21 points at 6 months, 3.71 points at 1 year, and 3.70 points at 2 years post-op. Mean ODI score was 37.0 points pre-op and improved to 27.0 points at 6 months, and 22.8 points at 1 and 2 years post-op. Mean SF-12 physical component score was 33.7 points at baseline, improving to 36.9 points at 6 months, 40.6 points at 1 year, and 40.5 points at 2 years post-op. Paired samples analysis comparing 6-month and 1-year post-op scores showed deterioration for numeric rating scale leg pain (p=0.05). There was a trend for improvement in SF-12 physical component score (p=0.06). Significant improvement between 6 months and 1 year post-op was noted for ODI (p=0.02) and SRS total score (p<0.0001). Comparison of 1- versus 2-year postoperative scores revealed no statistically significant differences for any of the HRQOL parameters.ConclusionsThis study supports the application of HRQOL measures, including the deformity-specific SRS-22, as a valuable tool in the assessment of adult deformity patients. Change in outcome score stabilized after the 1-year postoperative interval, for most patients.     

成人脊柱畸形术后近端交界区失败的研究进展

正近端交界区失败(proximal junctional failure,PJF)是发生在脊柱畸形矫形术后的一种特定的近端交界区病变,是一种伴有临床症状的严重的近端交界性后凸(proximal junctional kyphosis,PJK),也是成人脊柱畸形(adult spinal deformity,ASD)矫形手术的严重并发症。近年,国内外学者对脊柱畸形术后近端交界区病变做了大量的研究,笔者通过文献回顾,从PJF的定义、发生率、危险因素、预防和治疗等方面,对目前PJF的相关研究进展加以综述。     

AM-PAC mobility scores predict non-home discharge following adult spinal deformity surgery

BACKGROUND CONTEXTAdult spinal deformity (ASD) surgery requires an extended recovery period and often non-routine discharge. The Activity Measure for Post-Acute Care (AM-PAC) Basic Mobility Inpatient Short Form (6-Clicks) is a prediction tool, validated for other orthopedic procedures, to assess a patient's ability to mobilize after surgery.PURPOSETo assess the thresholds of AM-PAC scores that determine non-home discharge disposition in patients who have undergone ASD surgery.STUDY DESIGNRetrospective reviewPATIENT SAMPLENinety consecutive ASD patients with ≥5 levels fused who underwent surgery from 2015 to 2018, with postoperative AM-PAC scores measured before discharge, were included.OUTCOME MEASURESNon-home discharge dispositionMETHODSPatients with routine home discharge were compared to those with non-home discharge. Bivariate analysis was first conducted to compare these groups by preoperative demographics, comorbidities, radiographic alignment, surgical characteristics, HRQOLs, and AM-PAC measurements. Threshold linear regression with Bayesian information criteria was utilized to identify the optimal cutoffs for AM-PAC scores associated with increased likelihood of non-home discharge. Finally, multivariable analysis controlling for age, sex, comorbidities, levels fused, perioperative complication, and home support was conducted to assess each threshold.RESULTSThirty-six (40%) of 90 patients analyzed had non-home discharge. On bivariate analysis, first AM-PAC score (13.5 vs. 17), last AM-PAC score (17 vs. 20), and AM-PAC change per day (+.387 vs. +1) were all significantly associated with non-home discharge. Threshold regression identified that cutoffs of ≤15 for first AM-PAC score, <17 for last AM-PAC score, and <+0.625 for daily AM-PAC change were associated with non-home discharge. On multivariable analysis, first AM-PAC score ≤15 (odds ratio [OR] 11.28; confidence interval [CI] 2.96-42.99; p<.001), last AM-PAC score <17 (OR 33.57; CI 5.85-192.82; p<.001), and AM-PAC change per day <+0.625 (OR 6.24; CI 2.01-19.43; p<.001) were all associated with increased odds of non-home discharge.CONCLUSIONSFirst AM-PAC score of 15 or less can help predict non-home discharge. A goal of daily AM-PAC increases of 0.625 points toward a final AM-PAC score of 17 can aid in achieving home discharge. The early AM-PAC mobility threshold of ≤15 may help prepare for non-home discharge, while AM-PAC daily changes per day <0.625 and final AM-PAC <17 may provide goals for mobility improvement during the early postoperative period in order to prevent non-home discharge.     

Impact of body mass index on surgical outcomes and complications in adult spinal deformity

BackgroundSeveral studies have reported that overweightness and obesity are associated with higher complication rates in lumbar spine surgery. However, little is known about the effect of obesity on postoperative complications in adult spinal deformity (ASD) surgery, especially in the elderly. This study aimed to examine the effect of body mass index (BMI) on surgical outcomes and postoperative complications in elderly ASD patients undergoing surgical correction in Japan.MethodsWe conducted a retrospective, multicenter, observational study of 234 consecutive patients diagnosed with ASD who underwent corrective surgery. Patients were divided into two groups according to BMI, BMI <25 (153 patients, mean age 71.9 years) and BMI ≥ 25 (overweight/obese, 81 patients, mean age 73.3 years). Radiographic results and perioperative complications were compared between the two groups.ResultsSurgical complications occurred in approximately 20% of patients in each group; complications did not significantly differ between the two groups. A greater proportion of patients in the BMI ≥ 25 group experienced mechanical failure and DJK, although the difference was not significant. Preoperative mean lumbar lordosis (LL), pelvic incidence (PI) minus LL, sacral slope (SS) and sagittal vertical axis (SVA) were similar in the BMI < 25 and BMI ≥ 25 groups. However, the BMI ≥25 group had lower mean LL (p = 0.015) and higher PI minus LL (p = 0.09) postoperatively. The BMI ≥25 groups also had significantly smaller LL (p = 0.026), smaller SS (p = 0.049) and higher SVA (p = 0.041) at the final follow-up, compared to the BMI < 25 group.ConclusionsIn the present study, no difference in medical or surgical complications after ASD surgery was found between overweight/obese patients (BMI ≥ 25) and those with BMI < 25. However, correction of LL and SVA was smaller in patients with overweight/obese patients.