Establishing benchmarks for the volume-outcome relationship for common lumbar spine surgical procedures

Establishing case volume benchmarks for ACGME-accredited orthopedic surgery of the spine fellowship training

BACKGROUND CONTEXT

There has been increasing scrutiny on the standardization of surgical training in the US.

PURPOSE

This study provides case volume benchmarks for Accreditation Council for Graduate Medical Education (ACGME)-accredited orthopedic spine surgery fellowship training.

STUDY DESIGN/SETTING

This was a retrospective cross-sectional study of fellows at ACGME-accredited orthopedic spine surgery fellowships (2017-2022).

PATIENT SAMPLE

N/A.

OUTCOME MEASURES

Reported case volume during fellowship training.

METHODS

Case volume percentiles were calculated across ACGME-defined case categories and temporal changes assessed via linear regression. Variability between the highest and lowest deciles by case volume was calculated as fold-differences (90th percentile/10th percentile). Sensitivity analyses were performed to identify potential targets for case minimum requirements.

RESULTS

A total of 163 spine surgery fellows were included in this study. Total mean reported spine surgery case volume increased from 313.2±122 in 2017 to 382.0±164 in 2022 (p=.19). Most cases were classified as adult (range, 97.2%-98.0%) over pediatric cases (range, 2.0%-2.8%). An average of 322.0 cases were reported and most were classified as laminectomy (32%), posterior arthrodesis (29%), and anterior arthrodesis (20%). Overall variability in total case volume was 2.4 and the greatest variability existed for posterior instrumentation (38.1), application of cage (34.6), anterior instrumentation (20.8), and fractures and dislocations (17.3). If case minimum requirements for total reported cases was assumed at 200 cases, then all spine fellows included in this study would achieve this requirement. However, if case minimum requirements were assumed at 250 total cases, then approximately thirty percent of fellows (n=49) would not achieve this requirement for graduation.

CONCLUSIONS

Increasingly, national societies and accrediting bodies for surgical education recognize the need for standardized training. This study provides benchmarks to inform potential case minimum requirements and help reduce variability during spine fellowship training. Future studies are needed to establish case minimum requirements for spine surgery fellowship training across comprehensive and granular case categories that cover the full gamut of orthopedic spine surgery.

How Much Experience is Required to Acquire the Skills to Independently Perform Spine Surgery? What Milestones are Needed for Successful Surgery?

Purpose

To assess the number of surgeries needed to acquire the necessary skills to perform spine surgery independently.

Patients and Methods

A questionnaire on 12 different spinal procedures was sent to orthopedic surgeons affiliated with the spine teams of orthopedic departments at either the Akita University or Sapporo Medical University. Participants were asked to identify whether they (A) could independently perform each procedure, (B) could perform each procedure with the assistance of a senior doctor, or (C) were unable to perform each procedure. Those whose response was (A) were asked how many surgeries were required to acquire the necessary skills. Those who responded to (B) or (C) were asked how many surgeries they believed were required to acquire the skills necessary to operate independently. Participants also responded to 10 questions on surgical training techniques and rated the usefulness of each method.

Results

A total of 55 spine surgeons responded to the questionnaire. Group A required significantly fewer surgeries in the following categories to become independent than required Group C: upper cervical spine surgery (7.3/19.3), anterior cervical decompression/fusion (6.7/28.8), posterior cervical decompression/fusion (9.5/27.3), lumbar discectomy (12.6/26.7), endoscopic lumbar discectomy (10.2/24.2), spinal tumor resection (6.5/37.2), and spinal kyphosis surgery (10.3/32.3). Over 80% of participants responded that the following were effective methods: "surgeries where a senior doctor is the main surgeon, and the respondent is the assistant and observer"; "surgeries where the respondent is the main surgeon, and a senior doctor is an assistant"; "self-study using surgery manuals, articles, and textbooks"; and "training through video surgery sessions".

Conclusion

Surgeons who do not perform specific procedures independently require more surgical experience than those who operate independently. Our results may help develop more efficient training methods for spine surgeons.

Increased Surgeon-specific Experience and Volume is Correlated With Improved Clinical Outcomes in Lumbar Fusion Patients

STUDY DESIGN

The present study design was that of a single center, retrospective cohort study to evaluate the influence of surgeon-specific factors on patient functional outcomes at 6 months following lumbar fusion. Retrospective review of a prospectively maintained database of patients who underwent neurosurgical lumbar instrumented arthrodesis identified the present study population.

OBJECTIVE

This study seeks to evaluate surgeon-specific variable effects on patient-reported outcomes such as Oswestry Disability Index (ODI) and the effect of North American Spine Society (NASS) concordance on outcomes in the setting of variable surgeon characteristics.

SUMMARY OF BACKGROUND DATA

Lumbar fusion is one of the fastest growing procedures performed in the United States. Although the impact of surgeon-specific factors on patient-reported outcomes has been contested, studies examining these effects are limited.

METHODS

This is a single center, retrospective cohort study analyzing a prospectively maintained database of patients who underwent neurosurgical lumbar instrumented arthrodesis by 1 of 5 neurosurgery fellowship trained spine surgeons. The primary outcome was improvement of ODI at 6 months postoperative follow-up compared with preoperative ODI.

RESULTS

A total of 307 patients were identified for analysis. Overall, 62% of the study population achieved minimum clinically important difference (MCID) in ODI score at 6 months. Years in practice and volume of lumbar fusions were statistically significant independent predictors of MCID ODI on multivariable logistic regression ( P =0.0340 and P =0.0343, respectively). Concordance with evidence-based criteria conferred a 3.16 (95% CI: 1.03, 9.65) times greater odds of achieving MCID.

CONCLUSION

This study demonstrates that traditional surgeon-specific variables predicting surgical morbidity such as experience and procedural volume are also predictors of achieving MCID 6 months postoperatively from lumbar fusion. Independent of surgeon factors, however, adhering to evidence-based guidelines can lead to improved outcomes.

Comparison of cost and complication rates for profiling hospital performance in lumbar fusion for spondylolisthesis

BACKGROUND CONTEXT

There is growing interest among payers in profiling hospital value and quality-of-care, including both the cost and safety of common surgeries, such as lumbar fusion. Nonetheless, there is sparse evidence describing the statistical reliability of such measures when applied to lumbar fusion for spondylolisthesis.

PURPOSE

To evaluate the reliability of 90-day inpatient hospital costs, overall complications, and rates of serious complications for profiling hospital performance in lumbar fusion surgery for spondylolisthesis.

STUDY DESIGN/SETTING

Data for this analysis came from State Inpatient Databases from nine states made available through the Healthcare Cost and Utilization Project.

PATIENT SAMPLE

Patients undergoing elective lumbar spine fusion for spondylolisthesis from 2010 to 2017 in participating states.

OUTCOME MEASURES

Statistical reliability, defined as the ability to distinguish true performance differences across hospitals relative to statistical noise. Reliability was assessed separately for 90-day inpatient costs (standardized across years to 2019 dollars), overall complications, and serious complication rates.

METHODS

Statistical reliability was measured as the amount of variation between hospitals relative to the total amount of variation for each measure. Total variation includes both between-hospital variation ("signal") and within-hospital variation ("statistical noise"). Thus, reliability equals signal over (signal plus noise) and ranges from 0 to 1. To adjust for differences in patient-level risk and procedural characteristics, hierarchical linear and logistic regression models were created for the cost and complication outcomes. Random hospital intercepts were used to assess between-hospital variation. We evaluated the reliability of each measure by study year and examined the number of hospitals meeting different thresholds of reliability by year.

RESULTS

We included a total of 66,571 elective lumbar fusion surgeries for spondylolisthesis performed at 244 hospitals during the study period. The mean 90-day hospital cost was $30,827 (2019 dollars). 12.0% of patients experienced a complication within 90 days of surgery, including 7.8% who had a serious complication. The median reliability of 90-day cost ranged from 0.97to 0.99 across study years, and there was a narrow distribution of reliability values. By comparison, the median reliability for the overall complication metric ranged from 0.22 to 0.44, and the reliability of the serious complication measure ranged from 0.30 to 0.49 across the study years. At least 96% of hospitals had high (> 0.7) reliability for cost in any year, whereas only 0-9% and 0-11% of hospitals reached this cutoff for the overall and serious complication rate in any year, respectively. By comparison, 10%-69% of hospitals per year achieved a more moderate threshold of 0.4 reliability for overall complications, compared to 21%-80% of hospitals who achieved this lower reliability threshold for serious complications.

CONCLUSIONS

90-day inpatient costs are highly reliable for assessing variation across hospitals, whereas overall and serious complications are only moderately reliable for profiling performance. These results support the viability of emerging bundled payment programs that assume true differences in costs of care exist across hospitals.

An Employer-Provider Direct Payment Program Is Associated With Lower Episode Costs

Bundled payment has shown promise in reducing medical spending while maintaining quality. However, its impact among commercially insured populations has not been well studied. We examined the impacts on episode cost and patient cost sharing of a program that applies bundled payments for orthopedic and surgical procedures in a commercially insured population. The program we studied negotiates preferred prices for selected providers that cover the procedure and all related care within a thirty-day period after the procedure and waives cost sharing for patients who receive care from these providers. After implementation, episode prices for three selected surgical procedures declined by $4,229, a 10.7 percent relative reduction. Employers captured approximately 85 percent of the savings, or $3,582 per episode (a 9.5 percent relative decrease), and patient cost-sharing payments decreased by $498 per episode (a 27.7 percent relative decrease).

Complication Events After Spinal Surgery Performed by American Board of Orthopaedic Surgery (ABOS) Part II Candidates (2008-2017)

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

To evaluate complications following spine surgery using American Board of Orthopaedic Surgeons (ABOS) Part II examination data from 2008 to 2017.

SUMMARY OF BACKGROUND DATA

Recent research has demonstrated the importance of surgical experience and clinical volume in minimizing complications after spine surgery. This may be challenging for orthopedic spine surgeons who are just starting their practice.

METHODS

We performed a retrospective review of surgical cases submitted to the ABOS by candidates taking the Part II Spine examination between 2008 and 2017. Complications, including peri-operative mortality as reported by candidates to the ABOS, were tracked over time. Complications were classified as surgical or medical using a predefined algorithm. Multivariable Poisson regression analyses adjusting for confounders were used to assess rates of complications and mortality over time. All analyses controlled for biologic sex, age, surgical diagnosis, and surgical location.

RESULTS

A total of 37,539 spine surgical patients were analyzed, with an average of 3754 cases performed each year. Following adjusted Poisson analysis, we determined that cases in 2017 had an increased likelihood of complications when compared to those treated in 2008 (IRR 1.20; 95% CI 1.09, 1.32). Similar findings were encountered for surgical complications (IRR 1.20; 95% CI 1.07, 1.34). In contrast, spine surgical cases reported to the ABOS in 2017 had a 55% lower likelihood of mortality when compared to procedures performed in 2008 (IRR 0.45; 95% CI 0.24, 0.84; P = 0.01).

CONCLUSIONS

Our analysis of ABOS Part II candidates demonstrates that reported complication rates may be increasing while mortality is decreasing. The etiologies behind these findings are likely multifactorial. Encouragingly, we believe that observed reductions in mortality suggest overall improvements in patient safety following spine surgery. At a minimum, our data provide benchmarks through which spine surgeons, hospitals, and residency or fellowship programs can evaluate performance.Level of Evidence: 4.

Low Surgeon and Hospital Volume Increase Risk of Early Conversion to Total Knee Arthroplasty After Tibial Plateau Fixation

BACKGROUND

Some orthopaedic procedures exhibit volume-outcome relationships that suggest benefits associated with a triage and treatment by higher volume surgeons and hospitals. The purpose of this study was to determine whether this association is present for open reduction internal fixation (ORIF) of tibial plateau fractures regarding the outcome of conversion to total knee arthroplasty (TKA).

METHODS

The Florida State Inpatient Database was queried to identify patients who underwent ORIF of a tibial plateau fracture between 2006 and 2009. The annual volumes of surgeons and hospitals were determined. The outcome of interest was any subsequent hospitalization for TKA within 5 years. Comparing the rates of this outcome, cut points were established to define high and low volume. Survival analysis, including Cox proportional hazards modeling, was used to estimate the effect of volume on rates of TKA while controlling for patient factors and injury characteristics.

RESULTS

In this cohort of 3,921 patients, 172 patients (4.4%) underwent TKA within 5 years of ORIF of the tibial plateau. This included 5.0% of patients treated by low-volume surgeons versus 2.1% treated by high-volume surgeons and 4.8% treated at low-volume hospitals versus 2.0% treated at high-volume hospitals. High-volume surgeons and hospitals were defined by annual volumes greater than or equal to 7 and 29, respectively. After adjustment, treatment at a low-volume hospital was associated with a larger hazard of conversion to TKA (hazard ratio = 2.05; 95% confidence interval = 1.11 to 3.80). Treatment by a low-volume surgeon was also associated with a larger hazard of conversion to TKA (hazard ratio = 2.17; 95% confidence interval = 1.31 to 3.59).

DISCUSSION

High-volume treatment of tibial plateau fractures is associated with a lower rate of conversion to TKA, suggesting that the regionalization of care for these injuries may improve outcomes.

LEVEL OF EVIDENCE

Level III.

Comparison of Navigated versus Fluoroscopic-Guided Pedicle Screw Placement Accuracy and Complication Rate

OBJECTIVES

Accurate placement of the pedicle screw is requisite for any successful spinal instrumentation procedure. Screw insertion can be achieved using free-hand and fluoroscopic- or navigation-guided techniques. We sought to assess the variation in accuracy between fluoroscopic- and navigation-guided techniques, which are both used in Sheffield Teaching Hospitals National Health Service Trust, a tertiary spine referral center.

METHODS

Using a retrospective study design, we assessed all the pedicle screws placed between 2013 and 2018. Radiographic and clinical assessment of all cases was performed.

RESULTS

We studied 176 spinal instrumented cases, with a total of 831 screws implanted, out of which 296 (35.6%) were navigated and 535 (64.4%) were fluoroscopic guided. Pathology treated included spinal stenosis, spondylolisthesis, tumors, and trauma. Suboptimal screw position was identified in 2.03% (n = 6) of the navigation-guided series and 4.11% (n = 22) of the fluoroscopic-guided series with an overall screw misplacement rate of 3.4%. Evaluating surgeons' individual accuracy rates revealed that suboptimal screw placement registered a higher variation for the fluoroscopy-guided technique, and the misplacement rate was higher for surgeons with a lower volume of cases.

CONCLUSIONS

Use of navigation during spinal instrumentation helps lower the rate of screw misplacement for spinal surgeons who are at the beginning of their learning curve or do not frequently perform this kind of procedure. Navigation-guided spinal instrumentation is more accurate compared with fluoroscopic-guided techniques and appears to have a lower complication rate.

Is Treatment at a High-volume Center Associated with an Improved Survival for Primary Malignant Bone Tumors?

BACKGROUND

Centralization of cancer care to high-volume facilities has been shown to improve the overall survival of patients with soft-tissue sarcomas. Current evidence regarding the impact of increased hospital volume on treatment patterns and survival rates for patients with primary malignant bone tumors remains limited. Understanding the facility volume-outcome relationship for primary malignant bone tumors will further discussion on ways to promote delivery of quality cancer care across the nation.

QUESTIONS/PURPOSES

(1) Is there a difference in overall survival for patients with primary malignant bone tumors undergoing treatment at a high-volume facility (at least 20 patients per year) versus those treated at a low-volume facility (less than 20 patients per year)? (2) Do surgical treatment patterns (limb-salvage versus amputation) and margin status (positive versus negative) vary between high-volume and low-volume facilities?

METHODS

The 2004 to 2015 National Cancer Database was queried using International Classification of Disease for Oncology topographical codes to identify patients undergoing treatment (surgery, chemotherapy, and/or radiation therapy) for primary malignant bone tumors of the extremities (C40.0-C40.3, C40.8, and C40.9) or pelvis (C41.4). Histologic codes were used to group the tumors into the following categories: osteosarcomas, Ewing's sarcomas, chondrosarcomas, chordomas, and other or unspecified. Patients who did not receive any treatment (surgery, chemotherapy, and/or radiotherapy) at the reporting facility were excluded from the study. Facility volume was calculated based on the average number of patients per year for the entire study period. A preliminary stratified Cox regression model was used to identify evidence-based thresholds or cutoffs for high-volume and low-volume facilities, while adjusting for differences in patient, tumor, and treatment characteristics. We identified high-volume facilities as those treating at least 20 patients per year and low-volume facilities as those treating fewer than 20 patients per year. A Kaplan-Meier survival analysis was used to report overall unadjusted 5-year survival rates at high-volume and low-volume facilities. Multivariate Cox regression analyses were used to assess whether undergoing treatment at a high-volume facility was associated with a lower risk of overall mortality, after controlling for differences in baseline demographics, tumor presentation, and treatment characteristics. For patients undergoing surgery, multivariate regression models were used to evaluate whether patients receiving care in a high-volume facility were more likely to receive resections with limb salvage surgery than to receive amputation and whether facility volume was associated with a patient's likelihood of having a positive or negative surgical margin.

RESULTS

A total of 14,039 patients were included, 15% (2115) of whom underwent treatment in a high-volume facility. Patients undergoing treatment at a high-volume facility were more likely to be white, have tumors involving the pelvis, have larger tumor sizes, and have a higher tumor grade at presentation than those undergoing treatment at a low-volume facility. Unadjusted 5-year overall survival rates were greater for high-volume facilities than for low-volume facilities (65% versus 61%; p = 0.003). After controlling for differences in patient demographics, tumor characteristics (including histologic type, grade, stage, size, and location) and treatment factors, we found that patients treated at high-volume facilities had a slightly lower overall mortality risk than those treated at low-volume facilities (hazard ratio 0.85 [95% CI 0.77 to 0.93]; p < 0.001). Patients treated at high-volume facilities were also slightly more likely to undergo resection with limb-salvage surgery to than to undergo amputation (odds ratio 1.34 [95% CI 1.14 to 1.59]; p = 0.001). Patients undergoing surgical treatment at high-volume facilities also had a lower odds of having positive resection margins than those undergoing treatment at low-volume facilities (OR 0.56 [95% CI 0.44 to 0.72]; p < 0.001).

CONCLUSIONS

Patients undergoing treatment for primary malignant bone tumors at high-volume facilities experience a slightly better overall survival than those receiving treatment at low-volume facilities. Further research questioning the value of care at high-volume facilities is required before sweeping changes in regionalization can be considered.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Effect of Surgeon and Hospital Volume on Complications After Operative Tarsal Fracture Repair

OBJECTIVE

To determine whether increased surgeon and hospital volume is associated with lower rates of complications after tarsal fractures.

DESIGN

Retrospective cohort study of the State Inpatient Databases.

SETTING

Two hundred ninety-nine hospitals in Florida (2005-2012) and New York (2006-2008).

PATIENTS/PARTICIPANTS

Four thousand one hundred thirty-two tarsal fractures that underwent fixation by 1223 surgeons.

INTERVENTION

Surgical repair of tarsal fractures.

MAIN OUTCOME MEASUREMENTS

Composite of readmission for infection requiring operative treatment, wound dehiscence, nonunion, avascular necrosis, or amputation within 2 years of the index procedure.

RESULTS

The mean age was 44 (±15) years, a majority were men (70%) and white (69%), and the mean number of Charlson comorbidities was 0.21 (±0.58). Multivariable logistic regression demonstrated a reduction in the likelihood of complications by 9% for each 5 additional surgeries performed by the operating surgeon [odds ratio (OR), 0.91 per 5 surgeries; 95% confidence interval (CI), 0.82-0.99]. Other factors associated with complications included increased age (OR, 1.23 per 10 years; 95% CI, 1.10-1.36), male sex (OR, 1.56; 95% CI, 1.12-2.17), open fractures (OR, 2.84; 95% CI, 1.92-4.19), number of Charlson comorbidities (OR, 1.23; 95% CI, 1.02-1.48), income quartile (OR, 1.48; 95% CI, 1.00-2.17), uninsured (OR, 2.47; 95% CI, 1.39-4.39), and other government program insurance (OR, 1.52; 95% CI, 1.06-2.18).

CONCLUSIONS

We observed a significant inverse relationship between surgeon volume and complication rates when controlling for patient and injury characteristics. In contrast to previous research, a volume-outcome relationship was not observed at the hospital level. These results suggest that such complex injuries should be triaged to the most experienced providers.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Does Hospital Volume Affect Outcomes in Spine Surgeries? A Systematic Review

STUDY DESIGN

Systematic review.

OBJECTIVE

To assess the impact of hospital volume on postoperative outcomes in spine surgery.

SUMMARY OF BACKGROUND DATA

Several strategies have recently been proposed to optimize provider outcomes, such as regionalization to higher volume centers and setting volume benchmarks.

MATERIALS AND METHODS

We performed a systematic review examining the association between hospital volume and spine surgery outcomes. To be included in the review, the study population had to include patients undergoing a primary or revision spinal procedure. These included anterior/posterior cervical fusions, anterior/posterior lumbar fusions, laminectomies, discectomies, spinal deformity surgeries, and surgery for spinal malignancies. We searched the Pubmed, OVID MEDLINE (1966-2018), Google Scholar, and Web of Science (1900-2018) databases in January 2018 using the search criteria ("Hospital volume" OR "volume" OR "volume-outcome" OR "volume outcome") AND ("spine" OR "spine surgery" OR "lumbar" OR "cervical" OR "decompression" OR "deformity" OR "fusions"). There were no restrictions placed on study design, publication date, or language. The studies were evaluated with respect to the quality of methodology as outlined by the Grading of Recommendations Assessment, Development, and Evaluation system.

RESULTS

Twelve studies were included in the review. Studies were variable in defining hospital volume thresholds. Higher hospital volume was associated with statistically significant lower risks of postoperative complications, a shorter length of stay, lower cost of hospital stay, and a lower risk of readmissions and reoperations/revisions.

CONCLUSIONS

Our findings suggest a trend toward better outcomes for higher volume hospitals; however, further study needs to be carried out to define objective volume thresholds for specific spine surgeries for hospitals to use as a marker of proficiency.

The impact of anesthesia and surgical provider characteristics on outcomes after spine surgery

PURPOSE

Information regarding the impact of provider characteristics on perioperative outcomes in the spine surgery setting is limited. Existing studies primarily consider the impact of surgical provider volume. This analysis sought to identify the impact of anesthesiologist and surgeon volume and experience as well as anesthesia care team composition on adverse outcomes following anterior cervical discectomy and fusions (ACDF) and posterior lumbar fusions (PLF).

METHODS

We identified 5900 patients who underwent ACDF or PLF procedures at a high-volume orthopedic institution from 2005 to 2014. Provider characteristics of interest were anesthesiologist and surgeon volume and experience along with anesthesia care team composition. Multivariable logistic regression models were used to evaluate the outcomes of any complication, cardiopulmonary complication, and prolonged length of stay (> 7 days). Intraclass correlation coefficients were calculated to determine how much variation in outcomes could be explained by provider characteristics.

RESULTS

There were no significant relationships between provider characteristics and perioperative outcomes among ACDF patients. Within the PLF cohort, surgeon annual case volume > 25 was associated with decreased odds of prolonged length of stay, while anesthesia resident involvement was associated with increased odds of prolonged length of stay. Surgeon characteristics explained the greatest proportion of variation in outcomes while anesthesiologist characteristics explained the least.

CONCLUSIONS

Anesthesia provider volume and experience did not significantly impact the odds of adverse outcome for ACDF and PLF patients. Higher surgeon volume was exclusively associated with decreased odds of prolonged length of stay following PLF. Further study is necessary to determine if these relationships persist in a less-specialized setting. These slides can be retrieved under Electronic Supplementary Material.

Optimizing the Volume-Value Relationship in Laminectomy: An Evidence-Based Analysis of Outcomes and Economies of Scale

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

The objective of the present study was to establish evidence-based volume thresholds for surgeons and hospitals predictive of enhanced value in the setting of laminectomy.

SUMMARY OF BACKGROUND DATA

Previous studies have attempted to characterize the relationship between volume and value; however, none to the authors' knowledge has employed an evidence-based approach to identify thresholds yielding enhanced value.

METHODS

In total, 67,758 patients from the New York Statewide Planning and Research Cooperative System database undergoing laminectomy in the period 2009 to 2015 were included. We used stratum-specific likelihood ratio analysis of receiver operating characteristic curves to establish volume thresholds predictive of increased length of stay (LOS) and cost for surgeons and hospitals.

RESULTS

Analysis of LOS by surgeon volume produced strata at: <17 (low), 17 to 40 (medium), 41 to 71 (high), and >71 (very high). Analysis of cost by surgeon volume produced strata at: <17 (low), 17 to 33 (medium), 34 to 86 (high), and >86 (very high). Analysis of LOS by hospital volume produced strata at: <43 (very low), 43 to 96 (low), 97 to 147 (medium), 148 to 172 (high), and >172 (very high). Analysis of cost by hospital volume produced strata at: <43 (very low), 43 to 82 (low), 83 to 115 (medium), 116 to 169 (high), and >169 (very high). LOS and cost decreased significantly (P < 0.05) in progressively higher volume categories for both surgeons and hospitals. For LOS, medium-volume surgeons handle the largest proportion of laminectomies (36%), whereas very high-volume hospitals handle the largest proportion (48%).

CONCLUSION

This study supports a direct volume-value relationship for surgeons and hospitals in the setting of laminectomy. These findings provide target-estimated thresholds for which hospitals and surgeons may receive meaningful return on investment in our increasingly value-based system. Further value-based optimization is possible in the finding that while the highest volume hospitals handle the largest proportion of laminectomies, the highest volume surgeons do not.

LEVEL OF EVIDENCE

3.

Evolution in Surgical Approach, Complications, and Outcomes in an Adult Spinal Deformity Surgery Multicenter Study Group Patient Population

STUDY DESIGN

Retrospective review of a prospectively collected multicenter database.

OBJECTIVES

To evaluate the evolution of surgical treatment strategies, complications, and patient-reported outcomes for adult spinal deformity (ASD) patients.

SUMMARY OF BACKGROUND DATA

ASD surgery is associated with high complication rates. Evolving treatment strategies may reduce these risks.

METHODS

Adult patients undergoing ASD surgery from 2009 to 2016 were analyzed (n = 905). Preoperative and surgical parameters were compared across years. Subgroup analysis of 436 patients with minimum two-year follow-up was also performed.

RESULTS

From 2009 to 2016, there was a significant increase in the mean preoperative age (52 to 63.1, p < .001), body mass index (26.3 to 32.2, p = .003), Charlson Comorbidity index (1.4 to 2.2, p < .001), rate of previous spine surgery (39.8% to 53.1%, p = .01), and baseline disability (visual analog scale [VAS] back and leg pain) scores (p < .01), Oswestry Disability Index, and 22-item Scoliosis Research Society Questionnaire scores (p < .001). Preoperative Schwab sagittal alignment modifiers and overall surgical invasiveness index were similar across time. Three-column osteotomy utilization decreased from 36% in 2011 to 16.7% in 2016. Lateral lumbar interbody fusion increased from 6.4% to 24.1% (p = .004), anterior lumbar interbody fusion decreased from 22.9% to 16.7% (p = .043), and transforaminal lumbar interbody fusion/posterior lumbar interbody fusion utilization remained similar (p = .448). Use of recombinant human bone morphogenetic protein-2 (rhBMP-2) in 2012 was 84.6%, declined to 58% in 2013, and rebounded to 76.3% in 2016 (p = .006). Tranexamic acid use increased rapidly from 2009 to 2016 (13.3% to 48.6%, p < .001). Two-year follow-up sagittal vertical axis, pelvic tilt, pelvic incidence-lumbar lordosis, and maximum Cobb angles were similar across years. Intraoperative complications decreased from 33% in 2010 to 9.3% in 2016 (p < .001). Perioperative (<30 days, <90 days) complications peaked in 2010 (42.7%, 46%) and decreased by 2016 (24.1%, p < .001; 29.6%, p = .007). The overall complication rate decreased from 73.2% in 2008-2014 patients to 62.6% in 2015-2016 patients (p = .03). Two-year health-related quality of life outcomes did not significantly differ across the years (p > .05).

CONCLUSIONS

From 2009 to 2016, despite an increasingly elderly, medically compromised, and obese patient population, complication rates decreased. Evolving strategies may result in improved treatment of ASD patients.

LEVEL OF EVIDENCE

Level IV.

Alterations in 90-day morbidity, mortality, and readmission rates following spine surgery in Medicare Accountable Care Organizations (2009-2014)

BACKGROUND CONTEXT

The impact of Accountable Care Organizations (ACOs) on healthcare quality and outcomes, including morbidity, mortality, and readmissions, has not been substantially investigated, especially following spine surgery.

PURPOSE

To evaluate the impact of ACO formation on postoperative outcomes in the 90-day period following spine surgery.

STUDY DESIGN

Retrospective review of national Medicare claims data (2009-2014).

PATIENT SAMPLE

Patients who underwent one of four lumbar spine surgical procedures in an ACO or non-ACO.

OUTCOME MEASURES

The development of in-hospital mortality, complications or hospital readmission within 90 days of the surgical procedure.

METHODS

The primary outcome measures included postsurgical complications and readmissions at 90 days following surgery. In-hospital mortality and 30-day outcomes were considered secondarily. The primary predictor variable consisted of ACO enrollment designation. Multivariable logistic regression analysis was utilized to adjust for confounders and determine the independent effect of ACO enrollment on postsurgical outcomes. The multivariable model included a propensity score adjustment that accounted for factors associated with the preferential enrollment of patients in ACOs, namely, sociodemographic characteristics, medical co-morbidities, hospital teaching status, bed size, and location.

RESULTS

In all, there were 344,813 patients identified for inclusion in this analysis with 97% (n = 332,890) treated in non-ACOs and 3% (n = 11,923) in an ACO. Although modest changes were apparent across both ACOs and non-ACOs over the time-period studied, improvements were slightly more dramatic in non-ACOs leading to statistically significant differences in both 90-day complications and readmissions. Specifically, in the period 2012-2014, ACOs demonstrated an 18% increase in the odds of 90-day complications and a 14% elevation in the odds of 90-day readmissions when compared to non-ACOs. There was no difference in hospital mortality between ACOs and non-ACOs.

CONCLUSIONS

Our study of Medicare data from 2009 to 2014 failed to demonstrate superior reductions in postoperative morbidity, mortality, and readmissions for beneficiaries treated in ACOs as compared to non-ACOs. These results indicate that meaningful changes in postoperative outcomes should not be anticipated based on organizational participation in ACOs at present.

Relationship between surgeon volume and outcomes in spine surgery: a dose-response meta-analysis

Background

The relationship between surgeon volume and outcomes in spine surgery is unclear and published studies report inconsistent results. Therefore, a dose-response meta-analysis was conducted to clarify the influence of surgeon volume on outcomes in spine surgery.

Methods

PubMed, Embase, and The Cochrane Library were systematically searched without language limitation for observational studies which investigated the relationship between surgeon volume and outcomes in spine surgery. The primary outcome was postoperative morbidity and the secondary outcomes consisted of mortality, length of hospital stay, readmission, and hospital costs. For binary variable and continuous variable, odds ratios (ORs) with 95% CIs and weighted mean differences (WMDs) with 95% CIs were pooled respectively. Additionally, a dose-response meta-analysis was performed for the primary outcome.

Results

Eleven studies with 1,986,545 patients were included in the current meta-analysis. Pooled estimate indicated that a higher surgeon volume was associated with lower postoperative morbidity (OR, 0.62; 95% CI: 0.52-0.75; I²=93.9%), lower mortality (OR, 0.76; 95% CI: 0.66-0.87; I²=0), shorter length of hospital stay (WMD, -7.07; 95% CI: -7.08 to -7.06; I²=100%), less readmission (OR, 0.78; 95% CI: 0.72-0.85; I²=93.1%), and lower hospital costs (WMD, -25,497.47; 95% CI: -25,528.43 to -25,466.51; I²=100%). Dose-response analysis suggested a nonlinear relationship between surgeon volume and postoperative morbidity (P for nonlinearity less than 0.00001).

Conclusions

The current evidence indicate that higher surgeon volume is associated with lower morbidity and mortality, shorter length of hospital stay, less readmission, and lower hospital costs in spine surgery.

Perioperative Safety: Keeping Our Children Safe in the Operating Room

The entire operating room team is responsible for the safety of children in the operating room. As a leader in the operating room, the surgeon is impactful in ensuring that all team members are committed to providing this safe environment. This is achieved by the use of perioperative huddles or briefings, the use of appropriate surgical checklists, operating room standardization, surgeons proficient in the care they provide, and team members that embrace Just Culture.

Fixed and Variable Relationship Models to Define the Volume-Value Relationship in Spinal Fusion Surgery: A Macroeconomic Analysis Using Evidence-Based Thresholds

Objective

Increased surgical volume has been associated with improved patient outcomes at the surgeon and hospital level. To date, clinically meaningful stratified volume benchmarks have yet to be defined for surgeons or hospitals in the context of spinal fusion surgery. The objective of this study was to establish evidence-based thresholds using outcomes and cost to stratify surgeons and hospitals performing spinal fusion surgery by volume.

Methods

Using 155,788 patients undergoing spinal fusion surgery, we created and applied 4 models using stratum-specific likelihood ratio (SSLR) analysis of a receiver operating characteristic (ROC) curve. This statistical approach was used to generate 4 sets of volume thresholds predictive of increased length of stay (LOS) and increased cost for surgeons and hospitals.

Results

SSLR analysis of the 2 ROC curves by annual surgical volume produced 3 or 4 distinct volume categories. Analysis of LOS by annual surgeon spinal fusion volume produced 4 strata: low, medium, high, and very high. Analysis of LOS by annual hospital spinal fusion volume produced 3 strata: low, medium, and high. No relationship between volume and cost could be clearly defined based on the generation of ROC curves for surgeons or hospitals offering spinal fusion.

Conclusion

This study used evidence-based thresholds to identify a direct, variable relationship model between volume and outcomes of spinal fusion surgery, using LOS as a surrogate, for both surgeons and hospitals. A fixed relationship model was identified between surgeon and hospital volume and cost, as no statistically meaningful relationship could be established.

Sexual activity after spine surgery: a systematic review

INTRODUCTION

Sexual function is an important determinant of quality of life, and factors such as surgical approach, performance of fusion, neurological function and residual pain can affect it after spine surgery. Our aim was to perform a systematic review to collate evidence regarding the impact of spine surgery on sexual function.

METHODS

A systematic review of studies reporting measures of sexual function, and incidence of adverse sexual outcomes (retrograde ejaculation) after major spine surgery was done, regardless of spinal location. Pubmed (MEDLINE) and Google Scholar databases were queried using the following search words "Sex", "Sex life", "Sexual function", "Sexual activity", "retrograde ejaculation", "Spine", "Spine surgery", "Lumbar surgery", "Lumbar fusion", "cervical spine", "cervical fusion", "Spinal deformity", "scoliosis" and "Decompression". All articles published between 1997 and 2017 were retrieved from the database. A total of 81 studies were included in the final review.

RESULTS

Majority of the studies were retrospective case series and were low quality (Level IV) in evidence. Anterior lumbar approaches were associated with a higher incidence of retrograde ejaculation, especially with the utilization of transperitoneal laparoscopic approach. There is inconclusive evidence on the preferred sexual position following fusion, and also on the impact of BMP-2 usage on retrograde ejaculation/sexual dysfunction.

CONCLUSION

Despite limited evidence from high-quality articles, there is a general trend towards improvement of sexual activity and function after spine surgery. Future studies incorporating specific assessments of sexual activity will be required to address this important determinant of quality of life so that appropriate pre-operative counselling can be done by providers. These slides can be retrieved under Electronic Supplementary Material.

Setting the Benchmark for the Ground and Air Medical Quality in Transport International Quality Improvement Collaborative

OBJECTIVE

Critical care transport (CCT) supports regionalization of medical care. Focus on the quality of CCT care prompted the development of the Ground and Air Medical qUality in Transport (GAMUT) Quality Improvement collaborative database which tracks consensus quality metrics. The Institute of Medicine recommends benchmarking of comparative data to accelerate improvement. Herein, we report the strategies and rationale for GAMUT QI Collaborative benchmarking.

METHODS

The GAMUT database includes >350 programs internationally with >200,000 annual patient contacts. Evidence-based literature review performed in May 2016 and October 2017 identified benchmarking strategies were evaluated and summarized, specific to the GAMUT metrics. Statistical analyses include simple statistics and weighted expectation calculations for benchmark examples (Pearson chi-square with Bonferroni adjusted post-hoc z tests).

RESULTS

Evidence-based literature search yielded 70 articles, and 31 were selected for inclusion in our evidence table. 5 evidence-based benchmark strategies were considered: average (mean), average (median), adjusted benchmark (based on expected outcome), Achievable Benchmark of Care (ABC), and Delphi. ABC threshold establishes a higher target (90th percentile) forcing more programs to achieve higher performance.

CONCLUSION

Benchmarking is not well-suited for a single strategy and requires customized consideration based on each metric, though adjusted benchmark and ABC generally set higher performance benchmarks.