Revision Rate After Adult Deformity Surgery

Immediate Postoperative Change in the Upper Instrumented Screw-Vertebra Angle is a Predictor for Proximal Junctional Kyphosis and Failure

STUDY DESIGN

Retrospective review.

OBJECTIVES

To determine if change in position of upper instrumented vertebral (UIV) screw between intraoperative prone and immediate postoperative standing radiographs is a predictor for proximal junctional kyphosis or failure (PJK/PJF).

SUMMARY OF BACKGROUND DATA

Cranially directed UIV screws on postoperative radiographs have been found to be associated with PJK. Change in the screw position between intraoperative and immediate postoperative radiographs has not been studied.

MATERIALS AND METHODS

Patients with posterior fusion greater than or equal to three levels and UIV at or distal to T8, and minimum two-year follow-up were identified from a single-center database. Primary outcomes were radiographic PJK/PJF or revision for PJK/PJF. Demographic, surgical, and radiographic variables, including intraoperative screw-vertebra (S-V) angle, change in S-V angle, direction of UIV screw (cranial-neutral-caudal), and rod-vertebra (R-V) angle were collected.

RESULTS

Totally, 143 cases from 110 patients were included with a mean age of 62.9 years and a follow-up of 3.5 years. Fifty-four (38%) cases developed PJK/PJF, of whom 30 required a revision. Mean S-V angle was -0.9°±5.5° intraoperative and -2.8°±5.5° postoperative. The group with PJK/PJF had a mean S-V angle change of -2.5°±2.4 while the rest had a change of -1.0°±1.6 ( P =0.010). When the change in S-V angle was <5°, 33% developed PJK, this increased to 80% when it was ≥5° ( P =0.001). Revision for PJK/PJF increased from 16% to 60% when S-V angle changed ≥5° ( P =0.001). Regression analysis showed S-V angle change as a significant risk factor for PJK/PJF ( P =0.047, OR=1.58) and for revision due to PJK/PJF ( P =0.009, OR=2.21).

CONCLUSIONS

Change in the S-V angle from intraoperative prone to immediate postoperative standing radiograph is a strong predictor for PJK/PJF and for revision. For each degree of S-V angle change, odds of revision for PJK/PJF increases by x2.2. A change of 5° should alert the surgeon to the likely development of PJK/PJF requiring revision.

LEVEL OF EVIDENCE

Level II.

The Impact of Unplanned Reoperation Following Adult Spinal Deformity Surgery: A Prospective Longitudinal Cohort Study with 5-Year Follow-up

BACKGROUND

The long-term impact of reoperations following adult spinal deformity (ASD) surgery is still poorly understood. Our aim was to identify the relationship between unplanned reoperation and health-related quality of life (HRQoL) gain at 2 and 5 years of follow-up.

METHODS

We included patients enrolled in a prospective ASD database who underwent surgery ≥5 years prior to the start of the study and who had 2 years of follow-up data. Adverse events (AEs) leading to an unplanned reoperation, the time of reoperation occurrence, invasiveness (blood loss, surgical time, hospital stay), and AE resolution were assessed. HRQoL was measured with use of the Oswestry Disability Index, Scoliosis Research Society-22, and Short Form-36. Linear models controlling for baseline data and index surgery characteristics were utilized to assess the relationships between HRQoL gain at 2 and 5-year follow-up and the number and invasiveness of reoperations. The association between 5-year HRQoL gain and the time of occurrence of the unplanned reoperation and that between 5-year HRQoL gain and AE resolution were also investigated.

RESULTS

Of 361 eligible patients, 316 (87.5%) with 2-year follow-up data met the inclusion criteria and 258 (71.5%) had 5-year follow-up data. At the 2-year follow-up, 96 patients (30.4%) had a total of 165 unplanned reoperations (1.72 per patient). At the 5-year follow-up, 73 patients (28.3%) had a total of 117 unplanned reoperations (1.60 per patient). The most common cause of reoperations was mechanical complications (64.9%), followed by surgical site infections (15.7%). At the 5-year follow-up, the AE that led to reoperation was resolved in 67 patients (91.8%). Reoperation invasiveness was not associated with 5-year HRQoL scores. The number of reoperations was associated with lesser HRQoL gain at 5 years for all HRQoL measures. The mean associated reduction in HRQoL gain per unplanned reoperation was 41% (range, 19% to 66%). Reoperations resulting in no resolution of the AE or resolution with sequelae had a greater impact on 5-year follow-up HRQoL scores than reoperations resulting in resolution of the AE.

CONCLUSIONS

A postoperative, unplanned reoperation following ASD surgery was associated with lesser gain in HRQoL at 5 years of follow-up. The association did not diminish over time and was affected by the number, but not the magnitude, of reoperations. Resolution of the associated AE reduced the impact of the unplanned reoperation.

LEVEL OF EVIDENCE

Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.

Does the interfacing angle between pedicle screws and support rods affect clinical outcomes after posterior thoracolumbar fusion? A retrospective clinical study

BACKGROUND CONTEXT

Proper alignment and tightening of the pedicle screw/rod assembly after instrumented posterior fusion of the lower spine is known to be crucial in order to achieve satisfactory clinical results. Such interfacing angle mismatches indicate stress overloading of the implant system.

PURPOSE

The objective of this study is to investigate the incidence of postoperative screw/rod interfacing angle mismatch and to analyze the impact of mismatches on clinical outcome in terms of (1) revision surgery, (2) adjacent segment degeneration (ASD), and (3) pain.

STUDY DESIGN

This is a monocentric retrospective observational study.

PATIENT SAMPLE

Patients underwent fusion surgery with pedicle screw/rod systems for predominantly degenerative pathologies.

OUTCOME MEASURES

Pedicle screw/rod interfacing angle mismatch (mismatch is the angular deviation from 90° formed by the rod axis and the pedicle screw head axis as an indicator for missing form-fit) revision rate, ASD at the immediately adjacent cranial segment and VAS pain.

METHODS

Revision refers to subsequent procedures in which all or part of the original implant configuration is changed or removed. Radiographic parameters are evaluated using a/p and lateral radiographs at final follow-up. The interfacing angle mismatch between pedicle screw and rod is measured as the angle between two parallel lines on either side of each pedicle screw head and a line laterally along the associated rod. Multiple comparisons are counteracted by Bonferroni correction, adjusted significance level is at *p<.01.

RESULTS

Pedicle screw and rod interfacing angle mismatch was found in 171/406 (42.1%) of patients undergoing fusion surgery, affecting 613/3016 (20.3%) screws. The overall revision incidence was 11.8% (48/406), and a new ASD occurred in 12.1% of all patients (49/406) with an average follow-up of 5 years. Mean VAS pain score at final follow-up was 2.0. Comparison of the two groups with and without mismatches revealed statistically significantly higher (1) numbers of revision procedures performed (26.9% vs 0.9%), (2) numbers of new ASD developed (27.5% vs 3.8%), and (3) higher VAS pain scores (2.8/10 vs 1.4/10) for cases with mismatch. When comparing patients who underwent intraoperative correction and/or reduction with those who did not, statistically significant more screw mismatches (63.4% vs 39.7%) and revision surgeries (29.3% vs 9.9%) were noted in patients who had these forceful maneuvers.

CONCLUSIONS

Pedicle screw/rod interfacing angle mismatch is a frequent occurrence after fusion surgery. Mismatches indicate that the construct was assembled under mechanical stress. All preventable mechanical stresses, for example, unintentional uncontrolled forces on the instrumentation, should be avoided as much as possible, as they can negatively influence the clinical outcome.

Vertebral Bone Quality Score Independently Predicts Proximal Junctional Kyphosis and/or Failure After Adult Spinal Deformity Surgery

BACKGROUND

Proximal junctional kyphosis (PJK) and proximal junctional failure (PJF) can be catastrophic complications associated with adult spinal deformity (ASD) surgery. These complications are markedly influenced by osteoporosis, leading to additional vertebral fracture and pedicle screw loosening. The MRI-based vertebral bone quality score (VBQ) is a newly developed tool that can be used to assess bone quality.

OBJECTIVE

To investigate the utility of the VBQ score in predicting PJK and/or PJF (PJF/PJK) after ASD correction.

METHODS

We conducted a retrospective chart review to identify patients age ≥50 years who had received ASD surgery of 5 or more thoracolumbar levels. Demographic, spinopelvic parameters, and procedure-related variables were collected. Each patient's VBQ score was calculated using preoperative T1-weighted MRI. Univariate analysis and multivariate logistic regression were performed to determine potential risk factors of PJK/PJF. Receiver operating characteristic analysis and area-under-the-curve values were generated for prediction of PJK/PJF.

RESULTS

A total of 116 patients were included (mean age, 64.1 ± 6.8 years). Among them, 34 patients (29.3%) developed PJK/PJF. Mean VBQ scores were 3.13 ± 0.46 for patients with PJK/PJF and 2.46 ± 0.49 for patients without, which was significantly different between the 2 groups ( P < .001). On multivariate analysis, VBQ score was the only significant predictor of PJK/PJF (odds ratio = 1.745, 95% CI = 1.558-1.953, P < .001), with a predictive accuracy of 94.3%.

CONCLUSION

In patients undergoing ASD correction, higher VBQ was independently associated with PJK/PJF occurrence. Measurement of VBQ score on preoperative MRI may be a useful adjunct to ASD surgery planning.

Risk factors for unplanned reoperation after corrective surgery for adult spinal deformity

To determine the major risk factors for unplanned reoperations (UROs) following corrective surgery for adult spinal deformity (ASD) and their interactions, using machine learning-based prediction algorithms and game theory. Patients who underwent surgery for ASD, with a minimum of two-year follow-up, were retrospectively reviewed. In total, 210 patients were included and randomly allocated into training (70% of the sample size) and test (the remaining 30%) sets to develop the machine learning algorithm. Risk factors were included in the analysis, along with clinical characteristics and parameters acquired through diagnostic radiology. Overall, 152 patients without and 58 with a history of surgical revision following surgery for ASD were observed; the mean age was 68.9 years (SD 8.7) and 66.9 years (SD 6.6), respectively. On implementing a random forest model, the classification of URO events resulted in a balanced accuracy of 86.8%. Among machine learning-extracted risk factors, URO, proximal junction failure (PJF), and postoperative distance from the posterosuperior corner of C7 and the vertical axis from the centroid of C2 (SVA) were significant upon Kaplan-Meier survival analysis. The major risk factors for URO following surgery for ASD, i.e. postoperative SVA and PJF, and their interactions were identified using a machine learning algorithm and game theory. Clinical benefits will depend on patient risk profiles.

Improvements in Outcomes and Cost After Adult Spinal Deformity Corrective Surgery Between 2008 and 2019

STUDY DESIGN

A retrospective cohort study.

OBJECTIVE

To assess whether patient outcomes and cost-effectiveness of adult spinal deformity (ASD) surgery have improved over the past decade.

BACKGROUND

Surgery for ASD is an effective intervention, but one that is also associated with large initial healthcare expenditures. Changes in the cost profile for ASD surgery over the last decade has not been evaluated previously.

MATERIALS AND METHODS

ASD patients who received surgery between 2008 and 2019 were included. Analysis of covariance was used to establish estimated marginal means for outcome measures [complication rates, reoperations, health-related quality of life, total cost, utility gained, quality adjusted life years (QALYs), cost-efficiency (cost per QALY)] by year of initial surgery. Cost was calculated using the PearlDiver database and represented national averages of Medicare reimbursement for services within a 30-day window including length of stay and death differentiated by complication/comorbidity, revision, and surgical approach. Internal cost data was based on individual patient diagnosis-related group codes, limiting revisions to those within two years (2Y) of the initial surgery. Cost per QALY over the course of 2008-2019 were then calculated.

RESULTS

There were 1236 patients included. There was an overall decrease in rates of any complication (0.78 vs . 0.61), any reoperation (0.25 vs . 0.10), and minor complication (0.54 vs . 0.37) between 2009 and 2018 (all P <0.05). National average 2Y cost decreased at an annual rate of $3194 ( R2 =0.6602), 2Y utility gained increased at an annual rate of 0.0041 ( R2 =0.57), 2Y QALYs gained increased annually by 0.008 ( R2 =0.57), and 2Y cost per QALY decreased per year by $39,953 ( R2 =0.6778).

CONCLUSION

Between 2008 and 2019, rates of complications have decreased concurrently with improvements in patient reported outcomes, resulting in improved cost effectiveness according to national Medicare average and individual patient cost data. The value of ASD surgery has improved substantially over the course of the last decade.

Risk Factors for Revision Surgery After Primary Adult Thoracolumbar Deformity Surgery

STUDY DESIGN

This is a retrospective cohort study.

OBJECTIVE

The aim was to identify the risk factors for revision surgery within 2 years of patients undergoing primary adult spinal deformity (ASD) surgery.

SUMMARY OF BACKGROUND DATA

Previous literature reports estimate 20% of patients undergoing thoracolumbar ASD correction undergo reoperation within 2 years. There is limited published data regarding specific risk factors for reoperation in ASD surgery in the short term and long term.

METHODS

The authors queried the MarketScan database in order to identify patients who were diagnosed with a spinal deformity and underwent ASD surgery from 2007 to 2015. Patient-level factors and revision risk were investigated during 2 years after primary ASD surgery. Patients under the age of 18 years and those with any prior history of trauma or tumor were excluded from this study.

RESULTS

A total 7422 patients underwent ASD surgery during 2007-2015 in the data set. Revision rates were 13.1% at 90 days, 14.5% at 6 months, 16.7% at 1 year, and 19.3% at 2 years. In multivariate multiple logistic regression analysis, obesity [adjusted odds ratio (OR): 1.58, P<0.001] and tobacco use (adjusted OR: 1.38, P=0.0011) were associated with increased odds of reoperation within 2 years. Patients with a combined anterior-posterior approach had lower odds of reoperation compared with those with posterior only approach (adjusted OR: 0.66, P=0.0117).

CONCLUSIONS

Obesity and tobacco are associated with increased odds of revision surgery within 2 years of index ASD surgery. Male sex and combined surgical approach are associated with decreased odds of revision surgery.

Degenerative scoliosis of the spine: diagnosis, classification and surgical approach in older patients

Adult scoliosis is a deformity of the spine with an angle of more than 10 (according to Cobb) in people with a fully formed bone system. Due to the aging of the population, improvement of surgical techniques, creation of new implants and progress in anesthetic aids, the problem of degenerative scoliosis has been more and more frequently considered from the viewpoint of a surgical approach. There are many theories about the factors that contribute to the formation of degenerative scoliosis. The conservative therapy of degenerative scoliosis includes non-steroidal anti-inflammatory drugs, bracing, epidural and paravertebral injections with glucocorticosteroids and physical therapy. In case the conservative therapy is ineffective and there is a significant decrease in the quality of life, the issue of the surgical intervention is raised individually for each patient. Currently, the role and the volume of the surgical intervention in individuals with this pathology remains debatable. The choice of a surgical technique depends on a thorough assessment of clinical symptoms, neurological status, data of instrumental methods and a mandatory estimation of the parameters of the global vertebral-pelvic balance. Therefore, in this article, we pay special attention to the surgical algorithms based on the choice of the decompression type and the fusion length. We describe the generally accepted criteria for selecting the level of spondylosynthesis. Special attention is paid to the risk factors of the surgical treatment, as well as associated complications.

Importance of achieving Scoliosis Research Society-22r minimal clinically important difference for improving patient satisfaction after adult spinal deformity surgery

OBJECTIVE

Achievement of minimal clinically important differences (MCIDs) in the Scoliosis Research Society-22r (SRS-22r) subdomains represents surgical efficacy. However, whether achievements of MCIDs in SRS-22r domains are associated with long-term satisfaction in patients with adult spinal deformity (ASD) is unclear. This study aimed to elucidate factors affecting patient satisfaction after thoracopelvic corrective fusion surgery in patients with ASD.

METHODS

Data obtained in 187 patients with ASD who underwent extensive corrective fusion surgery from the thoracic spine to the pelvis between 2010 and 2017 and underwent follow-up for 2 years were retrospectively reviewed. The authors investigated the likelihood of achieving MCIDs in the function, pain, self-image, mental health, and subtotal domains 2 years after surgery. The following MCID values were used: function, 0.90; pain, 0.85; self-image, 1.05; mental health, 0.70; and subtotal, 1.05. Multivariate analysis was performed to evaluate factors associated with patient satisfaction 2 years after surgery.

RESULTS

The average satisfaction scores in the group that achieved MCID and the group that did not were as follows: 3.97 and 3.37 for function (p < 0.001), 3.66 and 3.51 for pain (p = 0.221), 3.84 and 3.06 for self-image (p < 0.001), 3.82 and 3.28 for mental health (p < 0.001), and 3.96 and 3.30 for subtotal (p < 0.001), respectively. Except for the pain domain, the group that achieved MCIDs showed greater satisfaction than the group that did not achieve MCIDs. On multivariate analysis, factors related to postoperative satisfaction were achievement of SRS-22r self-image (standardization coefficient 0.322, p < 0.001) and function (standardization coefficient 0.179, p = 0.026) MCIDs. Perioperative complications and revision surgery were not related to patient satisfaction.

CONCLUSIONS

Multivariate analysis demonstrated that achievement of MCIDs in SRS-22r self-image and function domains was significantly associated with postoperative satisfaction. Given that patients with poor preoperative health-related quality of life are more likely to achieve MCIDs in SRS-22r domains, surgeons should carefully consider whether to operate on patients with relatively good baseline health-related quality of life when making surgical decisions.

Predicting Reciprocal Thoracic Change, Proximal Junctional Kyphosis, and Revision Surgery in Adult Spinal Deformity

BACKGROUND

Compensatory mechanisms in patients with adult spinal deformity (ASD) that lead to poor quality of life include positive sagittal balance and pelvic retroversion. The objective of this retrospective review was to identify demographic and radiographic parameters of sagittal alignment that are correlated with thoracic kyphosis (TK), PJK, and reoperation in patients undergoing surgical correction for ASD.

METHODS

A single-center database of 155 patients with ASD undergoing surgery from 2008 to 2015 was reviewed. Patients >18 years old who underwent multilevel thoracolumbar fusion or fusion of thoracic vertebrae to the pelvis were included. Demographics and radiographic measurements of sagittal alignment were collected preoperatively, 6 weeks postoperatively, and 1 year postoperatively. Statistical analysis was performed to compare groups that did or did not develop change in thoracic kyphosis or PJK at early or late follow-up. Additionally, patients requiring reoperation were evaluated.

RESULTS

Increased thoracic kyphosis was associated with older age, hypolordosis, and comorbid PJK. Early PJK was associated with older age, hypolordosis, and increased T1 pelvic angle. Reoperation was associated with older age, higher positive sagittal balance, hypolordosis, and pelvic retroversion; PJK and thoracic kyphosis did not increase risk for reoperation.

CONCLUSIONS

Thoracic reciprocal change following surgical correction of ASD is highly associated with PJK, although neither increased risk of reoperation. PJK may be predicted by older age, hypolordosis, and increased T1 pelvic angle. Reoperation in patients with ASD is more likely in older patients with positive sagittal balance, a compensatory flat lower back, and compensatory pelvic retroversion.

Factors Associated with Improved Quality of Life Outcomes in Patients Undergoing Surgery for Adult Spinal Deformity

STUDY DESIGN

Retrospective longitudinal cohort study.

OBJECTIVE

This study aimed to elucidate factors affecting the likelihood of achieving minimum clinically important difference (MCID) to patient-reported outcomes defined by the Scoliosis Research Society-22r (SRS-22r) among patients with adult spinal deformity (ASD) who underwent extensive corrective fusion surgery from the thoracic spine to the pelvis.

SUMMARY OF BACKGROUND DATA

Achieving MCID for SRS-22r parameters was a measure of surgical efficacy. Patient characteristics and surgical and radiographic factors that affect the likelihood of achieving MCID for SRS-22r parameters are unknown.

METHODS

Data from patients with ASD who underwent extensive corrective fusion surgery from the thoracic spine to the pelvis during 2010 to 2016 were retrospectively reviewed. Data from a total of 167 patients with ≥2 years of follow-up were included. Multivariate analysis was used to investigate factors associated with the likelihood of achieving MCID for each of the SRS-22r domains (Function, Pain, Subtotal) 2 years after surgery. The following MCID values were used: 0.90 for Function, 0.85 for Pain, and 1.05 for the Subtotal.

RESULTS

MCID achievement rate was 36.5% for Function, 46.1% for Pain, and 44.3% for the Subtotal domain. In multivariate analysis, preoperative SRS-22r Function (odds ratio [OR] = 0.204, 95% confidence interval [CI] 0.105-0.396) increased the likelihood of achieving MCID for SRS-22r Function. Preoperative SRS-22r Subtotal (OR = 0.211, 95% CI, 0.107-0.413), preoperative pelvic tilt (OR = 1.072, 95% CI, 1.012-1.136), preoperative pelvic incidence minus lumbar lordosis (OR = 0.965, 95% CI, 0.934-0.997), and postoperative sagittal vertical axis (OR = 0.985, 95% CI, 0.974-0.995) affected the likelihood of achieving MCID for the SRS-22r Subtotal.

CONCLUSION

Patients with poor preoperative health-related quality of life were more likely to achieve improvement in SRS-22r parameters after extensive corrective fusion surgery for ASD. Achieving postoperative sagittal alignment increased the likelihood of achieving MCID for the SRS-22r Subtotal domain.Level of Evidence: 3.

Understanding Health Economics in Spine Surgery

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The United States has faced substantial increases in health-care expenditure, with specifically large increases in spine surgery costs.

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Many different formulas are utilized to determine value in spine surgery, including cost- benefit analyses, cost-effectiveness analyses, and cost-utility analyses, with the overall determination of value being quality/cost.

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Quality often is calculated indirectly using either process measures or outcome measures and represents the potential benefit of a given intervention, usually over a specific time period to yield quality-adjusted life years.

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Costs are particularly difficult to calculate given the interhospital, regional, national, and global variability, as well as indirect costs of an intervention, and many different methods are utilized to estimate costs.

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Spine surgeons should be familiar with the elements that compose cost-effectiveness and their potential shortcomings in order for providers and health-care policy makers to identify the highest-quality studies and interventions that provide the greatest benefit to patients.

State-of-the-art: outcome assessment in adult spinal deformity

Adult spinal deformity (ASD) is a diagnosis that encompasses heterogeneous disorders with an increasing prevalence. This increasing prevalence may be due to greater patient longevity or greater awareness of available treatments. Outcome assessment in ASD has evolved over the last 3 decades from physician-based assessments to a patient-centered perception of improvement. Outcome assessment that is reliable, accurate and responsive to change is especially important in ASD, as surgical treatment is known to carry a high cost and complication rate Glassman (Spine Deform 3:199-203, 2015); Glassman (Spine (Phila Pa 1976) 32: 2764-2770, 2007); Smith (J Neurosurg Spine 25:1-14, 2016). In an era of value-based care, diagnosis associated with such heterogeneity and high cost must provide sound evidence to support the cost versus outcome ratio. Numerous general health and disease specific patient-reported outcome measures (PROMs) have been utilized in ASD. We discuss these instruments in detail in the following state-of-the-art review.

Cost-effectiveness of adult lumbar scoliosis surgery: an as-treated analysis from the adult symptomatic scoliosis surgery trial with 5-year follow-up

STUDY DESIGN

Longitudinal comparative cohort.

OBJECTIVE

The purpose of this study is to report on the cost-effectiveness of surgical versus non-surgical treatment for Adult Symptomatic Lumbar Scoliosis (ASLS) using the as-treated data and provide a comparison to previously reported intent-to-treat (ITT) analysis. Adult spinal deformity is a relatively prevalent condition for which surgical treatment has become increasingly common but concerns surrounding complications, revision rates and cost-effectiveness remain unresolved. Of these issues, cost-effectiveness is perhaps the most difficult to quantify as the requisite data is difficult to obtain. The purpose of this study is to report on the cost-effectiveness of surgical versus non-surgical treatment for ASLS using the as-treated data and provide a comparison to previously reported ITT analysis.

METHODS

Patients with at least 5-year follow-up data within the same treatment arm were included. Data collected every 3 months included use of nonoperative modalities, medications and employment status. Costs for surgeries and non-operative modalities were determined using Medicare Allowable rates. Medication costs were determined using the RedBook and indirect costs were calculated based on the reported employment status and income. Quality-Adjusted Life Years (QALY) was determined using the SF-6D.

RESULTS

Of 226 patients, 195 patients (73 Non-op, 122 Op) met inclusion criteria. At 5 years, 29 (24%) patients in the Op group had a revision surgery of whom two had two revisions and one had three revisions. The cumulative cost for the Op group was $111,451 with a cumulative QALY gain of 2.3. The cumulative cost for the Non-Op group was $29,124 with a cumulative QALY gain of 0.4. This results in an ICER of $44,033 in favor of Op treatment.

CONCLUSION

This as-treated cost-effectiveness analysis demonstrates that surgical treatment for adult lumbar scoliosis becomes favorable at year-three, 1 year earlier than suggested by a previous intent-to-treat analysis.

LEVEL OF EVIDENCE

II.

State of the art advances in minimally invasive surgery for adult spinal deformity

Adult spinal deformity (ASD) can be associated with substantial suffering due to pain and disability. Surgical intervention for achieving neural decompression and restoring physiological spinal alignment has shown to result in significant improvement in pain and disability through patient-reported outcomes. Traditional open approaches involving posterior osteotomy techniques and instrumentation are effective based on clinical outcomes but associated with high complication rates, even in the hands of the most experienced surgeons. Minimally invasive techniques may offer benefit while decreasing associated morbidity. Minimally invasive surgery (MIS) for ASD has evolved over the past 20 years, driven by improved understanding of open procedures along with novel technique development and technologic advancements. Early efforts were hindered due to suboptimal outcomes resulting from high pseudarthrosis, inadequate correction, and fixation failure rates. To address this, multi-center collaborative groups have been established to study large numbers of ASD patients which have been vital to understanding optimal patient selection and individualized management strategies. Different MIS decision-making algorithms have been described to better define appropriate candidates and interbody selection approaches in ASD. The purpose of this state of the review is to describe the evolution of MIS surgery for adult deformity with emphasis on landmark papers, and to discuss specific MIS technology for ASD, including percutaneous pedicle screw instrumentation, hyperlordotic grafts, three-dimensional navigation, and robotics.

Predictors of 2-year reoperation in Medicare patients undergoing primary thoracolumbar deformity surgery

OBJECTIVE

This was a retrospective cohort study in which the authors used a nationally representative administrative database. Their goal was to identify the risk factors for reoperation in Medicare patients undergoing primary thoracolumbar adult spinal deformity (ASD) surgery. Previous literature reports estimate that 20% of patients undergoing thoracolumbar ASD correction undergo revision surgery within 2 years. Most published data discuss risk factors for revision surgery in the general population, but these have not been explored specifically in the Medicare population.

METHODS

Using the MarketScan Medicare Supplemental database, the authors identified patients who were diagnosed with a spinal deformity and underwent ASD surgery between 2007 and 2015. The interactions of patient demographics, surgical factors, and medical factors with revision surgery were investigated during the 2 years following primary ASD surgery. The authors excluded patients without Medicare insurance and those with any prior history of trauma or tumor.

RESULTS

Included in the data set were 2564 patients enrolled in Medicare who underwent ASD surgery between 2007 and 2015. The mean age at diagnosis with spinal deformity was 71.5 years. A majority of patients (68.5%) were female. Within 2 years of follow-up, 661 (25.8%) patients underwent reoperation. Preoperative osteoporosis (OR 1.58, p < 0.0001), congestive heart failure (OR 1.35, p = 0.0161), and paraplegia (OR 2.41, p < 0.0001) independently increased odds of revision surgery. The use of intraoperative bone morphogenetic protein was protective against reoperation (OR 0.71, p = 0.0371). Among 90-day postoperative complications, a wound complication was the strongest predictor of undergoing repeat surgery (OR 2.85, p = 0.0061). The development of a pulmonary embolism also increased the odds of repeat surgery (OR 1.84, p = 0.0435).

CONCLUSIONS

Approximately one-quarter of Medicare patients with ASD who underwent surgery required an additional spinal surgery within 2 years. Baseline comorbidities such as osteoporosis, congestive heart failure, and paraplegia, as well as short-term complications such as pulmonary embolism and wound complications significantly increased the odds of repeat surgery.

Cost-effectiveness of Operative versus Nonoperative Treatment of Adult Symptomatic Lumbar Scoliosis an Intent-to-treat Analysis at 5-year Follow-up

STUDY DESIGN

Secondary analysis using data from the NIH-sponsored study on adult symptomatic lumbar scoliosis (ASLS) that included randomized and observational arms.

OBJECTIVE

The aim of this study was to perform an intent-to-treat cost-effectiveness study comparing operative (Op) versus nonoperative (NonOp) care for ASLS.

SUMMARY OF BACKGROUND DATA

The appropriate treatment approach for ASLS continues to be ill-defined. NonOp care has not been shown to improve outcomes. Surgical treatment has been shown to improve outcomes, but is costly with high revision rates.

METHODS

Patients with at least 5-year follow-up data were included. Data collected every 3 months included use of NonOp modalities, medications, and employment status. Costs for index and revision surgeries and NonOp modalities were determined using Medicare Allowable rates. Medication costs were determined using the RedBook and indirect costs were calculated based on reported employment status and income. Qualityadjusted life year (QALY) was determined using the SF6D.

RESULTS

There were 81 of 95 cases in the Op and 81 of 95 in the NonOp group with complete 5-year follow-up data. Not all patients were eligible 5-year follow-up at the time of the analysis. All patients in the Op and 24 (30%) in the NonOp group had surgery by 5 years. At 5 years, the cumulative cost for Op was $96,000 with a QALY gain of 2.44 and for NonOp the cumulative cost was $49,546 with a QALY gain of 0.75 with an incremental cost-effectiveness ratio (ICER) of $27,480 per QALY gain.

CONCLUSION

In an intent-to-treat analysis, neither treatment was dominant, as the greater gains in QALY in the surgery group come at a greater cost. The ICER for Op compared to NonOp treatment was above the threshold generally considered cost-effective in the first 3 years of the study but improved over time and was highly cost-effective at 4 and 5 years.

LEVEL OF EVIDENCE

2.

Revision Risk After Primary Adult Spinal Deformity Surgery: A Nationwide Study With Two-Year Follow-up

STUDY DESIGN

Cohort study.

OBJECTIVES

To report the two-year revision risk following primary adult spinal deformity (ASD) surgery, describe reasons for revisions, and assess risk factors for revision surgery.

SUMMARY OF BACKGROUND DATA

Revision risk following primary ASD surgery has been reported to vary between 7% and 26%, but with loss to follow-up as a considerable challenge.

METHODS

Patients ≥18 years of age undergoing primary instrumented surgery for ASD in Denmark during 2006-2014 were identified by procedure and diagnosis codes in the Danish National Patient Registry (DNPR). Complete two-year follow-up on revision surgery for each patient was achieved. Medical records were reviewed to determine reasons for revisions. Overall comorbidity was summarized using the Charlson Comorbidity Index (CCI) based on DNPR data; low comorbidity (CCI 0); medium comorbidity (CCI 1-2); and high comorbidity (CCI ≥3). Risk factors for revision were assessed in a Cox regression model.

RESULTS

A total of 553 patients were identified. Of these, 19.9% were revised within the two-year follow-up and 7.2% of patients were revised more than once. Median time to revision was 308 days (interquartile range 105-508). The most common reason for revision was implant failure (38.2%) followed by infection (11.8%). Increased age (hazard ratio [HR] = 1.13, 95% confidence interval [CI] 1.01-1.26, per 10 years increment) and high comorbidity burden (HR = 2.10, 95% CI 1.16-3.79) were associated with increased revision risk. Risk of revision increased from 2006 to 2014; hence, year of primary surgery (with 2006 as reference) was associated with increased revision risk (HR = 1.09, 95% CI 1.01-1.18).

CONCLUSIONS

The revision risk within 2 years after primary ASD surgery was 19.9% nationwide in Denmark, and implant failure was the most common reason for revision. Increased comorbidity and age were separately associated with increased risk of revision.

LEVEL OF EVIDENCE

Level II.

Preoperative Assessment of Bone Quality in Spine Deformity Surgery: Correlation With Clinical Practice and Published Recommendations

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

The goals of this study were to (A) evaluate preoperative bone quality assessment and intervention practice over time and (B) review the current evidence for bone evaluation in spine fusion surgery.

SUMMARY OF BACKGROUND DATA

Deformity spine surgery has demonstrated improved quality of life in patients; however, its cost has made it controversial. If preoperative bone quality can be optimized then potentially these treatments could be more durable; however, at present, no clinical practice guidelines have been published by professional spine surgical organizations.

METHODS

A retrospective cohort review was performed on patients who underwent a minimum five-level primary or revision fusion. Preoperative bone quality metrics were evaluated over time from 2012 to 2017 to find potential trends. Subgroup analysis was conducted based on age, sex, preoperative diagnosis, and spine fusion region.

RESULTS

Patient characteristics including preoperative rates of pseudarthrosis and junctional failure did not change. An increasing trend of physician bone health documentation was noted (P = 0.045) but changes in other metrics were not significant. A sex bias favored females who had higher rates of preoperative DXA studies (P = 0.001), Vitamin D 25-OH serum labs (P = 0.005), Vitamin D supplementation (P = 0.022), calcium supplementation (P < 0.001), antiresorptive therapy (P = 0.016), and surgeon clinical documentation of bone health (P = 0.008) compared with men.

CONCLUSION

Our spine surgeons have increased documentation of bone health discussions but this has not affected bone quality interventions. A discrepancy exists favoring females over males in nearly all preoperative bone quality assessment metrics. Preoperative vitamin D level and BMD assessment should be considered in patients undergoing long fusion constructs; however, the data for bone anabolic and resorptive agents have less support. Clinical practice guidelines on preoperative bone quality assessment spine patients should be defined.

LEVEL OF EVIDENCE

4.

Stopping at Sacrum Versus Nonsacral Vertebra in Long Fusion Surgery for Adult Spinal Deformity: Meta-Analysis of Revision with Minimum 2-Year Follow-Up

OBJECTIVE

A pooled comparison was conducted on a revision to the sacrum (S) versus a nonsacral (NS) surgical strategy in adult spinal deformity (ASD).

METHODS

Strictly following the PRISMA 2009 guidelines, the MEDLINE, EMBASE, and Cochrane Library databases were used to search for studies published in English up to March 2018 that addressed the S versus NS surgical approach for a long fusion to treat ASD. Data on total revisions and revision reasons were extracted from the included studies and were pooled analyzed.

RESULTS

Eight retrospective studies with a total of 1846 ASD patients (528 S and 1318 NS) were included. The total revision rate was 11.38% (S: 17.80% and NS: 8.80%), and implant failure, pseudarthrosis, adjacent segment degeneration, and proximal junctional kyphosis (PJK) were common reasons for revision. The pooled results indicated that the NS group had decreased incident rates of total revision (95% confidence interval [CI] 1.20-2.32, P = 0.002; I2 = 0%) and pseudarthrosis (95% CI 2.16-15.44, P = 0.0005; I2 = 0%) compared with the S group. No significant differences were observed in implant failure (95% CI 0.86-3.90, P = 0.12; I2 = 0%), adjacent segment degeneration (95% CI 0.08-1.25, P = 0.10; I2 = 0%), and PJK (95% CI 0.54-6.88, P = 0.35; I2 = 0%) between the 2 groups.

CONCLUSIONS

Revision in ASD patients is a serious problem with a total rate of 11.38%, and implant failure, pseudarthrosis, adjacent segment degeneration, and PJK are common reasons for revision. Stopping at the sacrum vertebra in long fusion surgery on ASD patients seems to increase the incidence rates of total revision and pseudarthrosis.

Neurologic Comorbidities Predict Proximal Junctional Failure in Adult Spinal Deformity

STUDY DESIGN

Retrospective case-control matched cohort from a single institution.

OBJECTIVE

To examine the contribution of nonmechanical factors to the incidence of proximal junctional failure (PJF) after adult spinal deformity (ASD) surgery.

SUMMARY OF BACKGROUND DATA

Multiple studies have reported on the prevalence of PJF following surgery for ASD. However, little is known about the contribution of nonmechanical factors to the incidence of PJF.

METHODS

We identified a consecutive series of ASD patients who required revision surgery for PJF between 2013 and 2015. A matched cohort of ASD patients who did not develop PJF after surgical correction was identified based on age, gender, preoperative deformity type, number of fusion levels, and the lower instrumented vertebra level. We compared medical and surgical histories in the matched cohorts, with particular attention to the prevalence of preoperative neurologic comorbidities that might affect standing balance. Preoperative, immediate postoperative, and follow-up radiographs were reviewed to document specific characteristics of mechanical failure that resulted in PJF and required revision surgery.

RESULTS

Twenty-eight cases of PJF requiring revision surgery were identified. The prevalence rates of preoperative neurologic comorbidities in PJF cohort were significantly higher than in non-PJF cohort (75% vs. 32%, p < .001). Neurologic comorbidities included prior stroke (4), metabolic encephalopathy (2), Parkinson disease (1), seizure disorder (1), cervical and thoracic myelopathy (7), diabetic neuropathy (4), and other neuropathy (4). The mean preoperative sagittal vertical axis in PJF cohort was more positive compared with the non-PJF cohort (144 mm vs. 65 mm, p = .009) There were no significant differences in immediate postoperative or follow-up radiographic parameters between cohorts.

CONCLUSIONS

In this study, risk factors identified for the development of PJF included nonmechanical neurologic comorbidities, emphasizing the need to look beyond radiographic alignment in order to reduce the incidence of PJF.

LEVEL OF EVIDENCE

Level 3.

COMPARISON OF SURGICAL INTERVENTIONS FOR DEGENERATIVE DEFORMITIES AND INSTABILITY OF THE SPINE AMONG ELDERLY PATIENTS

ABSTRACT Objective: To evaluate the surgical results among elderly patients with degenerative deformities and instability of the spine. Methods: A retrospective study of 437 patients (337 women, 100 men) with a mean age 60. The mean follow-up time was five years. The inclusion criteria were diseases and complications following spinal trauma associated with deformities, degenerative processes, acute pain syndrome, and spinal stenosis with neurological deficit. Four study groups (A, B, C and D) were created and defined by type of surgical intervention. Group A patients (the reference group) - decompression of neural structures on both sides without fixation. Group B - decompression and transpedicular fixation performed without correction of the deformity. Group C - patients operated up to the lower-thoracic region with transpedicular screws, correction of the deformity and decompression of spinal stenosis. Group D - transpedicular fixation up to higher-thoracic region; correction of the deformity and decompression of neurological structures. The mean follow-up time was five years. Results: Group D patients achieved the best outcome. The results observed were good in 57.2% of cases (60 patients); satisfactory in 40% of cases (42 patients); and unsatisfactory in 2.8% of cases (three patients). The worst findings were observed in Group A: satisfactory in 13.4% of cases (15 patients); and, unsatisfactory in 86.6% of cases (97 patients). No good results were observed in this group. Conclusion: The results suggest that performing full deformity correction with transpedicular fixation up to the higher-thoracic region gives the best outcomes for elderly patients, and helps to prevent long-term complications. Evidence level III; Retrospective Comparative Study.

Impact of early unanticipated revision surgery on health-related quality of life after adult spinal deformity surgery

BACKGROUND CONTEXT

Revision surgery represents a major event for patients undergoing adult spinal deformity (ASD) surgery. Previous reports suggest that ASD surgery has minimal or no impact on health-related-quality of life (HRQOL) outcomes.

PURPOSE

The present study aims to investigate the impact of early reoperations within the first year on HRQOL and on the likelihood of reaching the minimally clinically important difference (MCID) after ASD surgery.

DESIGN

This is a retrospective analysis of prospectively collected data from consecutive surgically treated adult deformity surgery patients included in a multicenter, international database.

PATIENT SAMPLE

The present study included 280 patients from a multicenter international prospective database.

OUTCOME MEASURE

Oswestry Disability Index (ODI), Short Form-36 (SF-36), Scoliosis Research Society-22 (SRS-22), MCID were evaluated in this work.

METHODS

Consecutive surgical patients with ASD recruited prospectively in six different centers from four countries with a minimum 2-year follow-up were stratified into two groups: R (revision surgery within the first year) and NR (no revision). Health-related-quality of life (ODI, SF-36, SRS-22) was assessed and compared at 6-month, 1-year, and 2-year follow-up stages. Statistical analysis included chi-square tests, Student t tests, and linear mixed models.

RESULTS

Forty-three patients (R Group) received 46 revision surgeries. Nineteen patients (41.3%) had implant-related complications, 9 patients (19.6%) had deep surgical site infections, 9 patients (19.6%) had proximal junctional kyphosis, 3 patients (6.5%) had hematoma, and 6 patients (13%) had other complications. Baseline characteristics differed between groups. At 6 months, all HRQOL scores improved in both groups, except in the SF-36 Mental Component Summary and SRS-22 mental health domain in the R Group. At 1 year, ODI and SRS-22 improvement was significantly greater in the NR Group, exceeding the reported MCID. At the 2-year follow-up, ODI, SRS-22, SF-36 MCS, and SF-36 PCS improvement was similar in both groups. However, postoperative change was only above the MCID for SF-36 PCS, ODI, and SRS-22 in the NR Group.

CONCLUSIONS

Early unanticipated revision surgery has a negative impact on mental health at 6 months and reduces the chances of reaching an MCID improvement in SRS-22, SF-36 PCS, and ODI at the 2-year follow-up.

Differences in primary and revision deformity surgeries: following 1,063 primary thoracolumbar adult spinal deformity fusions over time

Background

This study aims to describe properties of adult spinal deformity (ASD) revisions relative to primary surgeries and determine clinical variables that can predict revision. ASD is a common pathology that can lead to decreased quality of life, pain, physical limitations, and dissatisfaction with self-image. Durability of interventions for deformity treatment is of paramount concern to surgeons, as revision rates remain high.

Methods

Patients undergoing thoracolumbar fusion, five or more levels, for scoliosis (primary diagnosis ICD-9 737.x) were identified on a state-wide database. Primary and revision (returning for re-fusion procedure) surgeries were compared based on demographic, hospital stay, and clinical characteristics. Differences between primary and revision surgeries, and predictors of primary surgeries requiring revision, utilized binary logistic regression controlling for age, comorbidity burden, and levels fused.

Results

A total of 1,063 patients (average 7.4 levels fused, mean age: 47.6 years, 69.0% female) undergoing operative treatment for ASD were identified, of which 123 (average 7.1 levels fused, 11.6%, mean age 61.43, 80.5% female) had surgical revision. Primary surgeries were ~0.3 levels longer (P=0.013), used interbody ~11% more frequently (P=0.020), and used BMP ~12% less frequently (P=0.008). Revisions occurred 176.4 days after the primary on average. The most frequent causes of revisions were: 43.09% implant failure, 24.39% acquired kyphosis, and 14.63% enduring scoliosis. After controlling for age, comorbidities, and levels fused older, more comorbid, female, and white-race patients were more likely to be revised. Upon multivariate regression, after controlling for age and levels fused, overall complications remained non-different (OR: 0.8, 95% CI: 0.6-1.2). However, revision remained an independent predictor for infection (OR: 5.5, 95% CI: 2.8-10.5).

Conclusions

In a statewide database with individual patient follow up of up to 4 years 10% of ASD patients undergoing scoliosis correction required revision. Revision surgeries had higher infection incidence.

Osteotomies in ankylosing spondylitis: where, how many, and how much?

INTRODUCTION

This article presents the current concepts of correction of spinal deformity in ankylosing spondylitis (AS) patients. Untreated AS can be a debilitating disease. In a few patients, disease progression results in severe spinal deformity affecting not only the thoracolumbar, but also the cervical spine. Surgery for correction in AS patients has a long history. With the advent of modern instrumentation, standardization of surgical and anesthesiologic techniques, surgical safety and corrective results could be improved and experiences from lumbar osteotomies could be transferred to the cervical spine.

METHODS

This article presents the current concepts of correction of spinal deformity in AS patients. In particular, questions regarding the localization and number of osteotomies, the optimal surgical target angle as well as planning and prediction of postoperative alignment are discussed.

RESULTS

Insight into recent technical developments, current challenges with correction and geometric analysis of center of rotation (COR) in cervical 3-column osteotomies (3CO) will be presented.

CONCLUSION

The article should encourage readers to improve surgical correction efficacy and provide a better understanding of correction geometry in 3CO for thoracolumbar and cervical spinal deformities.

TREATMENT OUTCOMES IN ELDERLY AND SENILE PATIENTS WITH DEGENERATIVE DEFORMATIONS AND INSTABILITY OF THE SPINAL COLUMN

Degenerative  scoliosis  is  a  prevalent  issue  among  the  aging  population.  Controversy  remains   over  the  role of surgical intervention in patients with such disease. The authors  present  the results of 14-year experience in treatment of this pathology.  Various approaches  to the surgical treatment depending  on the stage of the disease and the degree of deformation, including  decompression, instrumental posterior spinal fusion, anterior spinal fusion, and osteotomy were examined. Above treatment options are based on the analysis of clinical aspects, mechanical  stability of deformation, the degree of imbalance in the body and causes of pain or neurological  deficit.The  risk of postoperative complications is extremely  high and seems to be outweighed by the  possible successful outcomes of surgical treatment. The results presented in the treatment of degenerative scoliosis mainly provide positive outcomes and can assist in the selection of treatment for this group of patients.The purpose of the  study  is to  evaluate  the  treatment outcomes  of elderly  and  senile patients with  degenerative deformations and instability of the spinal column using various surgical techniques.Material and methods. During  the present  retrospective study the authors  analyzed 437 patients (337 (77%) women and  100  (23%)  men)  aged  60 years  and  older  who  underwent surgical  treatment at  Russian  Research  institute of traumatology and orthopaedics named  after  R.R.Vreden between  2000 and 2016. The  study  group  included  patients with  diseases and consequences  of injuries  in the  spine, leading  to its deformation and following spinal stenosis  with development of neurological  deficit in some cases.The  patients were subdivided into  four  groups  depending  on surgical  procedure.  Patients in group  I underwent decompression  of neural  structures at affected levels on both  sides without implants  for fixation. This group was used as the  comparison  group.  Patients in group  II  underwent fixation  the  affected  spinal  motion  segments  locally  with transpedicular system without correction of deformity  and with decompression  of neural structures at the level of spine stenosis.  Patients of group  III  underwent surgery  for fixation  of affected  PDS  up to lower thoracic  spine using short transpedicular system along with decompression  of the neural  structures and correction of spine deformity.  Patients in group IV underwent surgery  for fixation  of affected PDS  up to upper thoracic  spine using transpedicular system, bone cement, decompression  of neural structures and correction of spine deformity.The average postoperative follow up was 5 years (from 3 months  to 15 years), 266 patients were followed for more than three years.Results.  The  best  results   were  obtained  in  group  IV:  good  results   – 57,2%  (60  patients),  satisfactory  40% (42 patients), poor 2,8% (3 patients).The  worst  results  were  obtained in group  I: after  5 years  follow up satisfactory results  were  observed  in 13,4% (15 patients), poor in 86,6% (97 patients) and no good results were reported.Conclusion. Thus, the performed  study  and observed outcomes indicate  the rationale for performing a full deformity correction by transpedicular fixation and bone cement, applying all the required  methods  and techniques of osteotomy. This approach  allows to maximally  quickly  achieve  the  desired  treatment outcomes  in mid-and long-term follow up period and to avoid complications and revisions.

Posterior Versus Three-Column Osteotomy for Late Correction of Residual Coronal Deformity in Patients With Previous Fusions for Idiopathic Scoliosis

STUDY DESIGN

Retrospective case series.

OBJECTIVE

To compare the early results of posterior column (PCO) and three-column (3CO) osteotomies performed in patients with previously fused idiopathic scoliosis and review their abilities to achieve coronal correction of residual deformities.

SUMMARY OF BACKGROUND DATA

Residual deformity of previously fused AIS can accelerate adjacent segment degeneration secondary to lowest instrumented vertebra (LIV) tilt and rotation. Many of these patients are not satisfied with their cosmetic appearance and would choose revising the deformity when future surgery is indicated.

METHODS

The data from 29 consecutive patients who underwent PCOs or 3COs for late revisions of idiopathic scoliosis were reviewed. Measurements included Cobb angle, focal osteotomy angle, and coronal balance. Perioperative data, complications, and patient-reported outcomes were also reviewed.

RESULTS

Fourteen patients were treated with PCOs and 15 with 3COs. Global coronal correction was equal between the two groups. In the PCO group, where patients underwent a mean of 2.4 osteotomies, 20.2° of correction was obtained compared to 19.5° in the 3CO group (p = .33), which all underwent single osteotomies. The average coronal correction was 9.2°/osteotomy for the PCO group and 14.1°/osteotomy for the 3CO group (p < .01). Estimated blood loss was 1,417.5 mL in the PCO group compared to 3,199.3 in the 3CO group (p < .01). Five patients (36%) had intraoperative complications in the PCO group compared to 12 (80%) in the 3CO group (p < .05). There were no differences in operative times, length of stay, or patient-reported outcomes between groups.

CONCLUSION

PCOs and 3COs performed in patients with previously fused spines for idiopathic scoliosis are effective in achieving residual deformity correction. In cases of posterior fusions, where the patient has a mobile anterior column, PCOs should be considered over 3COs because of their decreased risk of blood loss and complications.

Increase in spinal deformity surgery in patients age 60 and older is not associated with increased complications

BACKGROUND CONTEXT

Surgical treatment for adult spinal deformity improves patient quality of life; however, trends in surgical utilization in the elderly, who may be at higher risk for complications, remain unclear.

PURPOSE

To identify trends in the utilization of adult deformity and determine complication rates among older patients.

STUDY DESIGN

This is a retrospective database analysis.

PATIENT SAMPLE

The Nationwide Inpatient Sample database was queried from 2004 to 2011 to identify adult patients who underwent spinal fusion of eight or more levels using International Classification of Diseases, Ninth Revision (ICD-9) coding.

OUTCOME MEASURES

Incidence of surgery, complication rates, length of stay, and total hospital charges.

METHODS

The incidence of surgery was normalized to United States census data by age group. Trends in complications, length of stay, and inflation-adjusted hospital charges were determined using linear regression and Cochran-Armitage trend testing.

RESULTS

An estimated 29,237 patients underwent adult spinal deformity surgery with an increase from 2,137 to 5,030 cases per year from 2004 to 2011. Surgical incidence among patients 60 years and older increased from 1.9 to 6.5 cases per 100,000 people from 2004 to 2011 (p<.001), whereas utilization in patients younger than 60 increased from 0.59 to 0.93. Linear regression revealed that the largest increase in surgical utilization was for patients aged 65-69 years with an increase of 0.68 patients per 100,000 people per year (p<.001), followed by patients aged 70-74 years with a rate of 0.56 patients per 100,000 people per year (p=.001). Overall complication rates were 22.5% in 2004 and 26.7% in 2011. Although complication risk increased with age (≥60 vs. <60: relative risk 1.91 [1.83, 1.99], p<.001), within-age group rates were stable over time. Mean length of stay was 9.6 days in 2004 and 9.0 days in 2011. Inflation-adjusted mean hospital charges increased from $171,517 in 2004 to $303,479 in 2011 (p<.001).

CONCLUSIONS

Operative management of adult spinal deformity increased 3.4-fold among patients ≥60 years from 2004 to 2011, with an associated 1.8-fold increase in hospital charges. Although the exact reasons for the striking increase in hospital charges remain unclear, some of the increase is likely related to decreasing reimbursement of charges by payors over the same period of time. The large majority of cases were performed in large academic centers, and growth in deformity trained spine specialists in these centers may have contributed to this trend. Despite the increased utilization of surgery for adult spinal deformity, in-hospital complications remained stable across all ages.

Impact of cost valuation on cost-effectiveness in adult spine deformity surgery

BACKGROUND CONTEXT

Over the past decade, the number of adult spinal deformity (ASD) surgeries has more than doubled in the United States. The complex surgeries needed to manage ASD are associated with significant resource utilization and high cost, making them a primary target for increased scrutiny. Accordingly, it is important to not only demonstrate value in ASD surgery as clinical effectiveness but also to translate outcome assessment to cost-effectiveness.

PURPOSE

To compare the difference between Medicare allowable rates and the actual, direct hospital costs for ASD surgeries.

STUDY DESIGN

Longitudinal cohort.

PATIENT SAMPLE

Consecutive patients enrolled in an ASD database from a single institution.

OUTCOME MEASURES

Short Form (SF)-6D.

METHODS

Consecutive patients enrolled in an ASD database from a single institution from 2008 to 2013 were identified. Direct hospital costs were collected from hospital administrative records for the entire inpatient episode of surgical care. Medicare allowable rates were calculated for the same inpatient stays using the year-appropriate Center for Medicare-Medicaid Services Inpatient Pricer Payment System Tool. The SF-6D, a utility index derived from the SF-36v1, was used to determine quality-adjusted life years (QALY). Costs and QALYs were discounted at 3.5% annually.

RESULTS

Of 580 surgical ASD patients eligible for 2-year follow up, 346 (60%) had complete baseline and 2-year data, and 60 were Medicare beneficiaries comprising the cohort for the present study. Mean SF-6D gained is 0.10 during year 1 after surgery and 0.02 at year 2, resulting in a cumulative SF-6D gain of 0.12 over 2 years. Mean Medicare allowable rate over the 2 years is $82,050 (range $42,383 to $220,749) and mean direct cost is $99,114 (range $28,447 to $217,717). Mean cost per QALY over 2 years is $683,750 using Medicare allowable rates and $825,950 using direct costs. This difference of $17,181 between the 2 cost calculation represents a 17% difference, which was statistically significant (p<.001).

CONCLUSIONS

There is a significant difference in direct hospital costs versus Medicare allowable rates in ASD surgery and in turn, there is a similar difference in the cost per QALY calculation. Utilizing Medicare allowable rates not only underestimates (17%) the cost of ASD surgery, but it also creates inaccurate and unrealistic expectations for researchers and policymakers.

Increasing Rates of Surgical Management of Multilevel Spinal Curvature in Elderly Patients

STUDY DESIGN

Retrospective analysis of Nationwide Inpatient Sample (NIS) database.

OBJECTIVE

To analyze trends in utilization and hospital charges for multilevel spinal curvature surgery in patients over 60 from 2004 to 2011.

SUMMARY OF BACKGROUND DATA

Multilevel spinal curvature has been increasingly recognized as a major source of morbidity in patients over sixty years of age. The economic burden of non-operative management for spinal curvature is elusive and likely underestimated. Though patient reported outcomes suggest that surgical treatment of spinal curvature may be superior to non-operative treatment in selected patients, surgical utilization trends remain unclear.

METHODS

Data were obtained from the NIS between 2004 and 2011. The NIS is the largest all-payer inpatient care database with approximately eight million annual patient discharges throughout the United States. Analysis included patients over age 60 with a spinal curvature diagnosis treated with a multi-level spinal fusion (≥3 levels fused) determined by ICD-9-CM diagnosis and procedure codes. Population-based utilization rates were calculated from US census data.

RESULTS

A total of 84,302 adult patients underwent multilevel spinal curvature surgery from 2004 to 2011. The annual number of ≥3 level spinal curvature fusions in patients over age 60 increased from 6,571 to 16,526, representing a 107.8% increase from 13.4 cases per 100,000 people in 2004 to 27.9 in 2011 (p < .001). Utilization rates in patients 65-69 years old experienced the greatest growth, increasing by 122% from 15.8 cases per 100,000 people to 35.1. Average hospital charges increased 108% from $90,557 in 2007 to $188,727 in 2011 (p < .001).

CONCLUSIONS

Rates of surgical management of multilevel spinal curvature increased from 2004 to 2011, exceeding growth of the 60+ age demographic during the same period. Growth was observed in all age demographics, and hospital charges consistently increased from 2004 to 2011 reflecting a per-user increase in expenditure.

LEVEL OF EVIDENCE

III.

Osteoporosis in Cervical Spine Surgery

STUDY DESIGN

Retrospective administrative database analysis.

OBJECTIVE

To investigate the effect of osteoporosis (OS) on complications and outcomes in patients undergoing cervical spine surgery.

SUMMARY OF BACKGROUND DATA

OS is the most prevalent degenerative human bone disease, and spine surgeons will inevitably perform procedures on patients with OS. These patients might present a difficult patient cohort because many fixation techniques depend on bone quality and adequate bone healing--both of which are compromised in OS.

METHODS

The nationwide inpatient sample was queried using the Ninth Revision, Clinical Modification procedural codes for cervical spine procedures and diagnosis codes for degenerative conditions of cervical spine from 2002 to 2011. Patients were separated into two cohorts, those patients with OS and those without OS. Demographics, hospital characteristics, and adjusted complication likelihood were analyzed. Multivariate regression analysis was performed to determine odds of revision surgery in patients with OS.

RESULTS

Of all patients undergoing degenerative cervical spine surgery, 2% were identified as having OS (32,557 of a sample of 1,602,129 patients). Osteoporotic patients were more likely to undergo posterior cervical spine fusion when compared with those patients without OS (11.3% vs. 5.4%, P < 0.0001). Moreover, circumferential fusion was performed 3 times more frequently in the osteoporotic cohort. Adjusted complications showed increased odds for postoperative hemorrhage (odds ratio = 1.70, 95% confidence interval = 1.46-1.98, P < 0.0001). Patients with OS stayed in the hospital longer (3.5 vs. 2.5 days, P < 0.0001) and had 30% costlier hospitalizations. Multivariate for revision surgery indicated that osteoporotic patients had significantly increased odds of revision surgery (odds ratio = 1.54, P ≤ 0.0001) when referenced to non-osteoporotic patients undergoing cervical spine surgery.

CONCLUSION

Osteoporotic patients were more likely to undergo revision surgery, have longer hospitalizations, and have higher hospitalization costs, than their non-osteoporotic counterparts.

LEVEL OF EVIDENCE

3.

Sagittal balance is more than just alignment: why PJK remains an unresolved problem

BACKGROUND

The durability of adult spinal deformity surgery remains problematic. Revision rates above 20 % have been reported, with a range of causes including wound infection, nonunion and adjacent level pathology. While some of these complications have been amenable to changes in patient selection or surgical technique, Proximal Junctional Kyphosis (PJK) remains an unresolved challenge. This study examines the contributions of non-mechanical factors to the incidence of postoperative sagittal imbalance and PJK after adult deformity surgery.

METHODS

We reviewed a consecutive series of adult spinal deformity patients who required revision for PJK from 2013 to 2015 and examined in their medical records in detail.

RESULTS

Neurologic disorders were identified in 22 (76 %) of the 29 PJK cases reviewed in this series. Neurologic disorders included Parkinson's disease (1), prior stroke (5), metabolic encephalopathy (2), seizure disorder (1), cervical myelopathy (7), thoracic myelopathy (1), diabetic neuropathy (5) and other neuropathy (4). Other potential comorbidities affecting standing balance included untreated cataracts (9), glaucoma (1) and polymyositis (1). Eight patients were documented to have frequent falls, with twelve cases having a fall right before symptoms related to the PJK were noted.

CONCLUSION

PJK is an important contributing factor to the substantial and unsustainable rate of revision surgery following adult deformity correction. Multiple efforts to avoid PJK via alterations in surgical technique have been largely unsuccessful. This study suggests that non-mechanical neuromuscular co-morbidities play an important role in post-operative sagittal imbalance and PJK. Recognizing the multi-factorial etiology of PJK may lead to more successful strategies to avoid PJK and improve surgical outcomes.