Abstract
Image guidance (IG) and robotics systems are becoming more widespread in their utilization and can be invaluable intraoperative adjuncts during spine surgery. Both are highly reliant upon ...stereotaxy and either pre- or intraoperative radiographic imaging. While user-operated IG systems have been commercially available longer and subsequently are more widely utilized across centers, robotics systems provide unique theoretical advantages over freehand and IG techniques for placing instrumentation within the spine. While there is a growing plethora of data showing that IG and robotic systems decrease the incidence of malpositioned screws, less is known about their impact on clinical outcomes. Both robotics and IG may be of particular value in cases of substantial deformity or complex anatomy. Indications for the use of these systems continue to expand with an increasing body of literature justifying their use in not only guiding thoracolumbar pedicle screw placement, but also in cases of cervical and pelvic instrumentation as well as spinal tumor resection. Both techniques also offer the potential benefit of reducing occupational exposures to ionizing radiation for the operating room staff, the surgeon, and the patient. As the use of IG and robotics in spine surgery continues to expand, these systems’ value in improving surgical accuracy and clinical outcomes must be weighed against concerns over cost and workflow. As newer systems incorporating both real-time IG and robotics become more utilized, further research is necessary to better elucidate situations where these systems may be particularly beneficial in spine surgery.
Retrospective, propensity-matched observational study.
To assess the impact of cell saver homologous transfusion on perioperative medical complications in adult patients undergoing spinal deformity ...surgery.
Despite many endorsing its use, many analyses still refute the efficacy of CS on decreasing total perioperative allogenic RBC transfusions, cost efficiency, and its effect on perioperative complications.
Adult patients that underwent spinal deformity surgery at a single center between 2015-2021 were retrospectively reviewed. Patient-specific, operative, radiographic, and 30-day complications/readmission data were collected for further analysis. Two methods were utilized to test our hypothesis: 1) absolute threshold model: two cohorts created among patients who received ≥550 mL of CS intraoperatively and those who received less; 2) adjusted ratio model: two cohorts created dependent on the ratio of CS to EBL. Propensity-score matching (PSM) and various statistical tests were utilized to test the association between CS and perioperative medical complications.
278 patients were included in this analysis with a mean age of 61.3±15.7yrs and 67.6% being female. Using the first method, 73 patients received ≥550 mL of CS and 205 received less. PSM resulted in 28 pairs of patients. 39.3% of patients with ≥550 mL CS required readmission within 30 days compared to 3.57% patients in the <550 mL cohort (P=0.016) despite a nearly identical proportion of patients requiring intraoperative blood transfusions (P>0.9999). Using the second method, 155 patients had CS/EBL< 0.33 and 123 with CS/EBL ≥0.33. 5.16% and 21.9% among patients with CS/EBL<0.33 and CS/EBL≥0.33 respectively, were readmitted by the 30 day marker (P<0.0001).
Our findings indicate that greater CS volumes transfused are associated with higher rates of 30-day readmissions. Thus, surgeons should consider limiting CS volume intraoperatively to 550 mL and when greater volumes are required or preferred, ensuring that the ratio of CS:EBL remains under 0.33.
Surgery for adult spinal deformity (ASD) poses substantial risks, including the development of symptomatic pseudarthrosis, which is twice as prevalent among patients with osteoporosis compared with ...those with normal bone mineral density (BMD). Limited data exist on the impact of teriparatide, an osteoanabolic compound, in limiting the rates of reoperation and pseudarthrosis after treatment of spinal deformity in patients with osteoporosis.
Osteoporotic patients on teriparatide (OP-T group) were compared with patients with osteopenia (OPE group) and those with normal BMD. OP-T patients were matched with OPE patients and patients with normal BMD at a 1:2:2 ratio. All patients had a minimum 2-year follow-up and underwent posterior spinal fusion (PSF) involving >7 instrumented levels. The primary outcome was the 2-year reoperation rate. Secondary outcomes included pseudarthrosis with or without implant failure, proximal junctional kyphosis (PJK), and changes in patient-reported outcomes (PROs). Clinical outcomes were analyzed using conditional logistic regression. Changes in PROs were analyzed using a mixed-effects model.
Five hundred and forty patients (52.6% normal BMD, 32.9% OPE, 14.4% OP-T) were included. In the unmatched cohort, 2-year reoperation rates (odds ratio OR = 0.45 95% confidence interval (CI): 0.20 to 0.91) and pseudarthrosis rates (OR = 0.25 95% CI: 0.08 to 0.61) were significantly lower in the OP-T group than the OPE group. Seventy-eight patients in the OP-T group were matched to 156 patients in the OPE group. Among these matched patients, at 2 years, 23.1% (36) in the OPE group versus 11.5% (9) in the OP-T group had a reoperation (OR = 0.45, p = 0.0188), 21.8% (34) versus 6.4% (5) had pseudarthrosis with or without implant failure (OR = 0.25, p = 0.0048), and 6.4% (10) versus 7.7% (6) had PJK (OR = 1.18, p = 0.7547), respectively. At 2 years postoperatively, PROs were better among OP-T patients than OPE patients. Subsequently, 78 patients in the OP-T group were matched to 156 patients in the normal BMD group. Among these matched patients, there was no significant difference in 2-year reoperation (OR = 0.85 95% CI: 0.37 to 1.98), pseudarthrosis (OR = 0.51 95% CI: 0.181 to 1.44), and PJK rates (OR = 0.77 95% CI: 0.28 to 2.06).
Osteoporotic patients on teriparatide demonstrated lower reoperation and symptomatic pseudarthrosis rates 2 years postoperatively compared with osteopenic patients. Moreover, patient-reported and clinical outcomes for osteoporotic patients on teriparatide were not different from those for patients with normal BMD.
Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.
Cervical spinal deformity (CSD) in adult patients is a relatively uncommon yet debilitating condition with diverse etiologies and clinical manifestations. Similar to thoracolumbar deformity, CSD can ...be broadly divided into scoliosis and kyphosis. Severe forms of CSD can lead to pain; neurologic deterioration, including myelopathy; and cervical spine–specific symptoms such as difficulty with horizontal gaze, dysphagia, and dyspnea. Recently, an increased interest is shown in systematically studying CSD with introduction of classification schemes and treatment algorithms. Both major and minor complications after surgical intervention have been analyzed and juxtaposed to patient-reported outcomes. An ongoing effort exists to better understand the relationship between cervical and thoracolumbar spinal alignment, most importantly in the sagittal plane.
STUDY DESIGN.Retrospective matched cohort analysis.
OBJECTIVE.To compare the accuracy of S2 alar-iliac (S2AI) screw placement by robotic guidance versus free hand technique.
SUMMARY OF BACKGROUND ...DATA.Spinopelvic fixation utilizing S2AI screws provides optimal fixation across the lumbosacral junction allowing for solid fusion, especially in long segment fusion constructs. Traditionally, S2AI screw placement has required fluoroscopic guidance for accurate screw placement. Herein, we present the first series comparing a free hand and robotic-guided technique for S2AI screw placement.
METHODS.Sixty-eight consecutive patients who underwent S2AI screw placement by either a free hand or robotic technique between 2015 and 2016 were reviewed. Propensity score-matching was utilized to control for preoperative characteristic imbalances. Screw position and accuracy were evaluated using three-dimensional manipulation of computed tomography scan reconstructions from intraoperative O-arm imaging.
RESULTS.A total of 51 patients (105 screws) were matched, 28 (59 screws) in the free hand group (FHG) and 23 (46 screws) in the robot group (RG). The mean age in the FHG and RG were 57.9 ± 14.6 years and 61.6 ± 12.0 years (P = 0.342), respectively. The average caudal angle in the sagittal plane was significantly larger in the RG (31.0 ± 10.0° vs. 25.7 ± 8.8°, P = 0.005). There was no difference between the FHG and RG in the horizontal angle, measured in the axial plane using the posterior superior iliac spine (PSIS) as a reference (41.1 ± 8.1° vs. 42.8 ± 6.6°, P = 0.225), or the S2AI to S1 screw angle (9.4 ± 7.0° vs. 11.3 ± 9.9°, P = 0.256), respectively. There was no difference in the overall accuracy between FHG and RG (94.9% vs. 97.8%, P = 0.630). Additionally, there were no significant intraoperative neurovascular or visceral complications associated with S2AI screw placement.
CONCLUSION.Free hand and robotic-guided S2AI screw placement both prove to be safe, accurate, and reliable techniques for achieving spinopelvic fixation.Level of Evidence3
Purpose
This study aimed to evaluate whether adult spinal deformity patients undergoing revision for symptomatic pseudarthrosis have comparable two-year outcomes as patients who do not experience ...pseudarthrosis.
Methods
Patients whose indexed procedure was revision for pseudarthrosis (pseudo) were compared with patients who underwent a primary procedure and did not have pseudarthrosis by 2Y post-op (non-pseudo). Patients were propensity-matched (PSM) based on baseline (BL) sagittal alignment, specifically C7SVA and CrSVA-Hip. Key outcomes were 2Y PROs (SRS and ODI) and reoperation. All patients had a minimum follow-up period of two years.
Results
A total of 224 patients with min 2-year FU were included (pseudo = 42, non-pseudo = 182). Compared to non-pseudo, pseudo-patients were more often female (
P
= 0.0018) and had worse BL sagittal alignment, including T1PA (
P
= 0.02, C2-C7 SVA
P
= 0.0002, and CrSVA-Hip
P
= 0.004. After 37 PSM pairs were generated, there was no significant difference in demographics, BL and 2Y alignment, or operative/procedural variables. PSM pairs did not report any significantly different PROs at BL. Consistently, at 2Y, there were no significant differences in PROs, including SRS function 3.9(0.2) vs 3.7(0.2),
P
= 0.44, pain 4.0 (0.2) vs. 3.57 (0.2),
P
= 0.12, and ODI 25.7 (5.2) vs 27.7 (3.7),
P
= 0.76. There were no differences in 1Y (10.8% vs 10.8%,
P
> 0.99) and 2Y (13.2% vs 15.8%,
P
= 0.64) reoperation, PJK rate (2.6% vs 10.5%,
P
= 0.62), or implant failure (2.6% vs 10.5%,
P
= 0.37). Notably, only 2 patients (5.4%) had recurrent pseudarthrosis following revision. Kaplan–Meier curves indicated that patients undergoing intervention for pseudarthrosis had comparable overall reoperation-free survival (log-rank test,
χ
2 = 0.1975 and
P
= 0.66).
Conclusions
Patients undergoing revision for pseudarthrosis have comparable PROs and clinical outcomes as patients who never experienced pseudarthrosis. Recurrence of symptomatic pseudarthrosis was infrequent.
Understanding the scope of the volume and costs of lumbar fusions and discectomy procedures, as well as identifying significant trends within the Medicare system, may be beneficial in enhancing ...cost-efficiency and care delivery. However, there is a paucity of studies which analyze recent trends in lumbar fusion volume, utilization, and reimbursements.
This study seeks to define the costs of lumbar fusions and discectomy procedures and identify trends and variations in volume, utilization, and surgeon and hospital reimbursement rates in the Medicare system between 2012 and 2017.
Retrospective database study.
Medicare Part A and Part B claims submitted for lumbar spine procedures from 2012 to 2017, as documented in the Centers for Medicare & Medicaid Services Physician and Other Supplier Public Use Files.
Procedure numbers and payments per episode.
This cross-sectional study tracked annual Medicare claims and payments to spine surgeons using publicly-available databases and aggregated data at the county level. Descriptive statistics and multivariate regression models were used to evaluate trends in procedure volume, utilization rates (per 10,000 Medicare beneficiaries), and reimbursement rates, and to examine associations between county-specific and lumbar spine procedure utilization and reimbursements.
A total of 772,532 lumbar spine procedures were performed in the Medicare population from 2012 to 2017, including 634,335 lumbar fusion surgeries and 138,197 primary lumbar discectomy and microdiscectomy single-level surgeries. There was a 26.0% increase in annual lumbar fusion procedure volume during the study period, with a compound annual growth rate (CAGR) of 4.7%. Lumbar discectomy/microdiscectomy experienced a 23.5% decrease in annual procedure volume (CAGR, −5.2%). Mean Medicare surgeon reimbursements for lumbar fusions nominally decreased by 3.7% from $767 in 2012 to $738 in 2017, equivalent to an inflation-adjusted decrease of 11.4% (CAGR, −0.7%). Mean Medicare payments for lumbar discectomy and microdiscectomy procedures nominally increased by 16.3% from $517 in 2012 to $601 in 2017, equivalent to an inflation-adjusted increase of 6.9% (CAGR, 3.1%).
This present study found the volume and utilization of lumbar fusions have increased since 2012, while lumbar discectomy and microdiscectomy volume and utilization have fallen. Medicare payments to hospitals and surgeons for lumbar fusions have either declined or not kept pace with inflation, and reimbursements for lumbar discectomy and microdiscectomy to hospitals have risen at a disproportionate rate compared to surgeon payments. These trends in Medicare payments, especially seen in decreasing allocation of reimbursements for surgeons, may be the effect of value-based cost reduction measures, especially for high-cost orthopedic and spine surgeries.
Anterior cervical discectomy and fusion (ACDF) has been considered the gold standard for treating various cervical spine pathologies stemming from cervical degenerative disorders. While cervical ...artificial disc replacement has emerged as an alternative in select cases, ACDF still remains a commonly performed procedure.
This study seeks to define the costs of ACDF and identify trends and variations in ACDF volume, utilization, and surgeon and hospital reimbursement rates.
Retrospective analysis of patients undergoing ACDF
Medicare patients undergoing ACDF between 2012 and 2017
ACDF volume, utilization rates, and surgeon/hospital reimbursement rates
This study tracked annual Medicare claims and payments to ACDF surgeons using publicly-available databases and aggregated data at the county level. Descriptive statistics and multivariate regression models were used to evaluate trends in procedure volume, utilization rates (per 10,000 Medicare beneficiaries), and reimbursement rates, and to examine associations between county-specific variables (ie, urban or rural, average household income, poverty rate, percent Medicare population, race/ethnicity demographics), and ACDF utilization and reimbursement rates.
A total of 264,673 ACDF surgeries were performed in the Medicare population from 2012 to 2017, with a 24.2% increase in annual procedure volume. Utilization also increased by 6.5% from 8.0 surgeries per 10,000 Medicare beneficiaries in 2012 to 8.5 in 2017. Hospital reimbursements for cervical spine fusion surgeries without complications or co-morbidities experienced nominal and inflation-adjusted increases of 9.5% and 0.7%, respectively, from $12,030.11 in 2012 to $13,167.64 in 2017. Surgeon reimbursements for single-level and multilevel ACDF each nominally decreased from $958.11 and $1,173.01, respectively, in 2012 to $950.34 and $1,138.41 in 2017 (a 0.8% and 2.9% decrease, respectively), but after adjusting for inflation, reimbursements per case fell by an average of 8.7% and 10.7%, respectively. In contrast, mean reimbursements per case for hospitals rose by 7.1% (1.5% inflation-adjusted decrease). A significant upward yearly trend in ambulatory surgical centers volume, resulted in a net increase of 184.5% between 2015 and 2017 (p<.001).
While ACDF volume and utilization has continued to increase since 2012, Medicare payments to hospitals and surgeons have struggled to keep up with inflation. Our study confirms that Medicare reimbursement per case continues to decrease at a disproportionate rate for surgeons, compared to hospitals. The increasing trend in procedures performed at ambulatory surgical centers shows promise for a future model of cost-efficient and value-based care.
Study Design.
Asymptomatic Multi-Ethnic Alignment Normative Study (MEANS) cohort: cross-sectional, multi-center. Symptomatic cohort: retrospective, multi-surgeon, single-center.
Objective.
To assess ...the association of odontoid-coronal vertical axis (OD-CVA) and orbital-coronal vertical axis (ORB-CVA) with radiographic parameters, patient-reported outcomes (PROs), and clinical outcomes.
Summary of Background Data.
Previous literature studied the OD-CVA in an asymptomatic cohort and ORB-CVA in a symptomatic cohort, demonstrating their correlations with radiographic parameters and ORB-CVA with outcomes.
Methods.
468 asymptomatic adult participants were prospectively enrolled in the MEANS cohort. 174 symptomatic ASD patients with 6 fused levels and 2-year follow-ups were retrospectively enrolled in the symptomatic cohort. The association between OD-CVA and ORB-CVA, and radiographic parameters, perioperative variables, PROs, and outcomes were analyzed. Pearson’s correlation was used to assess correlation and logistic regression odds of outcomes.
Results.
In the MEANS cohort, the ORB-CVA correlated with C7-CVA (r=0.58) and OD-CVA (r=0.74). In the symptomatic cohort, preoperative ORB-CVA correlated better with leg length discrepancy (LLD) (r=0.17,
P
=0.029) while preoperative OD-CVA correlated better with C7-CVA (r=0.90,
P
<0.001). Postoperative ORB-CVA correlated with postoperative C7-CVA (r=0.66,
P
<0.001) and postoperative OD-CVA correlated stronger with postoperative C7-CVA (r=0.81,
P
<0.001). Both preoperative OD-CVA (r=0.199) and ORB-CVA (r=0.208) correlated with preoperative Oswestry Disability Index (ODI). ORB-CVA correlated better than OD-CVA in the preoperative SRS-22r pain category but worse in total and other subcategories. Preoperative ORB-CVA was associated with increased odds of intraoperative complication (OR=1.28, 1.01-1.22), like OD-CVA (OR=1.30, 1.12-1.53). Neither preoperative ORB-CVA nor OD-CVA was associated with reoperations and readmissions after multivariate analysis. Preoperative OD-ORB mismatch >1.5 cm was not associated with increased odds of intraoperative and postoperative complications, reoperations, or readmissions.
Conclusion.
ORB-CVA and OD-CVA correlated with radiographic parameters, PROs, and intraoperative complications. ORB-CVA and OD-CVA can be used interchangeably as cranial coronal parameters in ASD surgery.
Multi-Ethnic Alignment Normative Study (MEANS) cohort: prospective, cross-sectional, multi-center.
To analyze the distribution of GAP scores in the MEANS cohort and compare the spinal shape via ...stratification by GAP alignment category, age, and country.
The GAP score has been used to categorize spinal morphology and prognosticate adult spinal deformity surgical outcomes and mechanical complications. We analyzed a large, multiethnic, asymptomatic cohort to assess the distribution of GAP scores.
467 healthy volunteers without spinal disorders were recruited in 5 countries. Sagittal radiographic parameters were measured via the EOS imaging system. The GAP total and constituent factor scores were calculated for each patient. Kruskal-Wallis rank sum test was performed to compare variables across groups, followed by post hoc Games Howell test. Fisher's exact test was used to compare categorical variables. The significance level was set to P<0.05.
In the MEANS cohort, 13.7% (64/467) of volunteers were≥60 years old, and 86.3% (403/467) were<60 years old. 76.9% (359/467) was proportioned, 19.5% (91/467) was moderately disproportioned, and 3.6% (17/467) was severely disproportioned. There was no significant difference in the frequency of proportioned, moderately, or severely disproportioned GAP between subjects from different countries (P=0.060). Those with severely disproportioned GAP alignment were on average 14.5 years older (P=0.016), had 23.1° lower magnitude lumbar lordosis (LL) (P<0.001), 14.2° higher pelvic tilt (P<0.001), 13.3° lower sacral slope (P<0.001), 24.1° higher pelvic-incidence (PI)-LL mismatch (P<0.001), 18.2° higher global tilt (P<0.001) than those with proportioned GAP; thoracic kyphosis and PI were not significantly different (P>0.05).
The GAP system applies to a large, multi-ethnic, asymptomatic cohort. Spinal alignment should be considered on a spectrum, as 19.5% of the asymptomatic volunteers were classified as moderately disproportioned and 3.6% severely disproportioned. Radiographic malalignment does not always indicate symptoms or pathology.
3.
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