Optimal imaging follow-up strategies for conservatively managed cerebral cavernous malformations: a cost-effectiveness analysis

J Neurosurg 143:1555–1566, 2025

This study evaluates cost-effectiveness of MRI surveillance intervals for conservatively managed cerebral cavernous malformations (CCMs) using a Markov model and Monte Carlo simulations. It compares 0.5-, 1-, 2-, and 3-year follow-up strategies for brainstem versus nonbrainstem CCMs, calculating lifetime costs, QALYs, and net monetary benefit from a US societal perspective.

Results indicate annual MRI is most cost-effective for brainstem CCMs, while a 3-year MRI interval is preferred for nonbrainstem CCMs, with findings robust to sensitivity analyses that varied hemorrhage rates, mortality, and MRI costs. The authors emphasize individualized follow-up based on symptoms, Zabramski grade, family history, and lesion multiplicity, and note model limitations and US-centric cost data.

Optimal MRI Follow-up for Brainstem CCM: Annual MRI follow-up (every 1 year) is the most cost-effective strategy for conservatively managed, unruptured brainstem cerebral cavernous malformations (CCM), balancing cost and quality-adjusted life years (QALYs).

Optimal MRI Follow-up for Nonbrainstem CCM: MRI follow-up every 3 years is the most cost-effective approach for nonbrainstem CCM, with less frequent imaging justified by lower rupture and rehemorrhage rates.

Markov Model and Monte Carlo Simulation: A decision-analytic Markov model with Monte Carlo simulations was used to compare different MRI follow-up intervals (0.5, 1, 2, and 3 years) for both brainstem and nonbrainstem CCM, incorporating costs, effectiveness (QALYs), and net monetary benefit (NMB).

Key Drivers of Cost-effectiveness: The cost-effectiveness of follow-up strategies is highly sensitive to annual rates of CCM rupture, mortality after rupture, and the cost of MRI; higher hemorrhage or mortality rates favor more frequent imaging.

Individualization of Follow-up: Follow-up intervals should be tailored based on lesion location, symptoms, prior hemorrhage, Zabramski grade, family history, and multiplicity, as higher-risk patients may benefit from closer surveillance.

Brainstem Lesion Risks: Brainstem CCMs have higher annual rupture (2.8%) and rehemorrhage rates (32.3%) compared to nonbrainstem lesions, resulting in greater disability and loss of quality of life, justifying more vigilant follow-up.

MRI Cost Thresholds: As the annual MRI cost increases above $6,581 for brainstem CCM and $8,995 for nonbrainstem CCM, less frequent MRI follow-up (every 2 years) becomes more cost-effective than the previously optimal intervals.

Limitations: The model does not distinguish between cerebellar and supratentorial nonbrainstem lesions, does not account for comorbidities or detailed imaging findings (e.g., Zabramski grade), and uses US-based cost data, which may limit generalizability to other healthcare settings.

Cost-effectiveness of posterior lumbar interbody fusion and/or transforaminal lumbar interbody fusion for grade 1 lumbar spondylolisthesis: a 5-year Quality Outcomes Database study

J Neurosurg Spine 41:596–603, 2024

Posterior lumbar interbody fusion (PLIF) and/or transforaminal lumbar interbody fusion (TLIF), referred to as “PLIF/TLIF,” is a commonly performed operation for lumbar spondylolisthesis. Its long-term cost-effectiveness has not been well described. The aim of this study was to determine the 5-year cost-effectiveness of PLIF/TLIF for grade 1 degenerative lumbar spondylolisthesis using prospective data collected from the multicenter Quality Outcomes Database (QOD).

METHODS Patients enrolled in the prospective, multicenter QOD grade 1 lumbar spondylolisthesis module were included if they underwent single-stage PLIF/TLIF. EQ-5D scores at baseline, 3 months, 12 months, 24 months, 36 months, and 60 months were used to calculate gains in quality-adjusted life years (QALYs) associated with surgery relative to preoperative baseline. Healthcare-related costs associated with the index surgery and related reoperations were calculated using Medicare reimbursement–based cost estimates and validated using price transparency diagnosis-related group (DRG) charges and Medicare charge-to-cost ratios (CCRs). Cost per QALY gained over 60 months postoperatively was assessed.

RESULTS Across 12 surgical centers, 385 patients were identified. The mean patient age was 60.2 (95% CI 59.1–61.3) years, and 38% of patients were male. The reoperation rate was 5.7%. DRG 460 cost estimates were stable between our Medicare reimbursement–based models and the CCR-based model, validating the focus on Medicare reimbursement. Across the entire cohort, the mean QALY gain at 60 months postoperatively was 1.07 (95% CI 0.97–1.18), and the mean cost of PLIF/TLIF was $31,634. PLIF/TLIF was associated with a mean 60-month cost per QALY gained of $29,511. Among patients who did not undergo reoperation (n = 363), the mean 60-month QALY gain was 1.10 (95% CI 0.99–1.20), and cost per QALY gained was $27,591. Among those who underwent reoperation (n = 22), the mean 60-month QALY gain was 0.68 (95% CI 0.21–1.15), and the cost per QALY gained was $80,580.

CONCLUSIONS PLIF/TLIF for degenerative grade 1 lumbar spondylolisthesis was associated with a mean 60-month cost per QALY gained of $29,511 with Medicare fees. This is far below the well-established societal willingness-to-pay threshold of $100,000, suggesting long-term cost-effectiveness. PLIF/TLIF remains cost-effective for patients who undergo reoperation.

 

Comparing Retreatments and Expenditures in Flow Diversion Versus Coiling for Unruptured Intracranial Aneurysm Treatment

Neurosurgery 87:63–70, 2020

Flow diverters (FDs) have marked the beginning of innovations in the endovascular treatment of large unruptured intracranial aneurysms, but no multiinstitutional studies have been conducted on these devices from both the clinical and economic perspectives.

OBJECTIVE: To compare retreatment rates and healthcare expenditures between FDs and conventional coiling-based treatments in all eligible cases in Japan.

METHODS: We identified patients who had undergone endovascular treatments during the study period (October 2015-March 2018) from a national-level claims database. The outcome measures were retreatment rates and 1-yr total healthcare expenditures, which were compared among patientswho had undergone FD, coiling, and stent-assisted coiling (SAC) treatments. The coiling and SAC groups were further categorized according to the number of coils used. Retreatment rates were analyzed using Cox proportional hazards models, and total expenditures were analyzed using multilevel mixed-effects generalized linear models.

RESULTS: The study sample comprised 512 FD patients, 1499 coiling patients, and 711 SAC patients. The coiling groups with ≥10 coils and ≥9 coils had significantly higher retreatment rates than the FD group with hazard ratios of 2.75 (1.30-5.82) and 2.52 (1.24-5.09), respectively. In addition, the coiling group with≥10 coils and SAC group with≥10 coils had significantly higher 1-year expenditures than the FD group with cost ratios (95% CI) of 1.30 (1.13-1.49) and 1.31 (1.15-1.50), respectively.

CONCLUSION: In this national-level study, FDs demonstrated significantly lower retreatment rates and total expenditures than conventional coiling with ≥ 9 coils.

Greening the Operating Room: Results of a Scalable Initiative to Reduce Waste and Recover Supply Costs

Neurosurgery 85:432–437, 2019

Operating rooms generate 42% of a hospital’s revenue and 30% of hospital waste. Supply costs are 56% of a total operating room (OR) budget. US academic medical centers use 2 million pounds ($15 million) of recoverable medical supplies annually. Forming a multidisciplinary leadership team, we analyzed sources of waste focusing on our Department of Neurosurgery. We developed an 8-wk pilot project to recycle “blue wrap,” the number 5 plastic polypropylene material that is ubiquitously used in ORs across the country to wrap instrument pans and implant trays for sterilization. Blue wrap can be baled and sold to recyclers where the material is pelletized and transformed into plastic products.

During the 39 d of the pilot, we collected 1247 pounds of blue wrap (32 lbs collected daily). The cost of the pilot was $14987 that includes a new baler ($11200) and 5 transport carts ($3697). The revenue received from baled blue wrap was 8 cents per pound. Cost avoidance yielded $31680.00 in savings. Implementation of this pilot across our main hospital would yield $5000 in revenue annually and $174.240 in cost avoidance.

This project can be replicated at other centers and not only reduces the environmental footprint, but also helps generate additional revenue by recycling a necessary packing material that would otherwise require payment for disposal.

 

Assessment of costs in open surgery and stereotactic radiosurgery for vestibular schwannomas

J Neurosurg 131:561–568, 2019

Microsurgical resection and radiosurgery remain the most widely used interventions in the treatment of vestibular schwannomas. There is a growing demand for cost-effectiveness analyses to evaluate these two treatment modalities and delineate the factors that drive their total costs. Here, the authors evaluated specific cost drivers for mi- crosurgical and radiosurgical management of vestibular schwannoma by using the Value Driven Outcomes system avail- able at the University of Utah.

METHODS The authors retrospectively reviewed all cases involving microsurgical and radiosurgical treatment of ves- tibular schwannomas at their institution between November 2011 and September 2017. Patient and tumor characteristics, subcategory costs, and potential cost drivers were analyzed.

RESULTS The authors identified 163 vestibular schwannoma cases, including 116 managed microsurgically and 47 ad- dressed with stereotactic radiosurgery (SRS). There were significant differences between the two groups in age, tumor size, and preoperative Koos grade (p < 0.05), suggesting that indications for treatment were markedly different. Length of stay (LOS) and length of follow-up were also significantly different. Facility costs were the most significant contributor to both microsurgical and SRS groups (58.3% and 99.4%, respectively); however, physician professional fees were not spe- cifically analyzed. As expected, microsurgical treatment resulted in an average 4-fold greater overall cost of treatment than for SRS cases (p < 0.05), and there was a greater variation in costs for open cases as well. Costs remained stable over time for both open resection and SRS. Multivariable analysis showed that LOS (b = 0.7, p = 0.0001), discharge dis- position (b = 0.2, p = 0.004), nonserviceable hearing (b = 0.1, p = 0.02), and complications (b = 0.2, p = 0.005) affected cost for open surgery, whereas no specifically examined factor could be identified as driving costs for SRS.

CONCLUSIONS This analysis identified the fact that facility utilization constitutes the majority of total costs for both microsurgery and SRS treatment modalities of vestibular schwannomas. LOS, discharge disposition, nonserviceable hearing, and complications contributed significantly to the total costs for the microsurgical group, whereas none of the factors could be identified as driving total costs for the SRS group. This information may be used to establish policies and protocols to reduce facility costs, with the goal of decreasing the total costs without jeopardizing patient care.

Cost-Effectiveness in Adult Spinal Deformity Surgery

Neurosurgery 83:597–601, 2018

The complexity and heterogeneity of adult spinal deformity (ASD) creates significant difficulties in performing high-quality, complete economic analyses. For the same reasons, however, such studies are immensely valuable to clinicians and health policy experts. There has been a paradigm shift towards value-based healthcare provision and as such, there is an increasing focus on demonstrating not just the value ASD surgery, but the provision of care at large. Health-related quality of life measures are an important tool for assessing value of an intervention and its effect on a quality-adjusted life year (QALY). Currently, there are no definitive criteria in regard to assigning the appropriate value to a QALY. A general accepted threshold discussed in literature is $100 000 per QALY gained. However, this figure may be variable across populations, and may not necessarily be applicable in today’s economy, or in all healthcare economies. Fundamentally, an effective treatment method may be associated with a high upfront cost, however, if durable, will be costeffective over time. The emphasis on carotid endarterectomy and CUA in the field of adult spine deformity is relatively recent; therefore, there is a limited amount of data on cost-effectiveness analyses. Continued efforts with emphasis on value-based outcomes are needed with long-term follow-up studies.

Cost Utility Analysis of the Cervical Artificial Disc vs Fusion for the Treatment of 2-Level Symptomatic Degenerative Disc Disease: 5-Year Follow-up

mobi-c

Neurosurgery 79:135–145, 2016

The cervical total disc replacement (cTDR) was developed to treat cervical degenerative disc disease while preserving motion.

OBJECTIVE: Cost-effectiveness of this intervention was established by looking at 2-year follow-up, and this update reevaluates our analysis over 5 years.

METHODS: Data were derived from a randomized trial of 330 patients. Data from the 12- Item Short Form Health Survey were transformed into utilities by using the SF-6D algorithm. Costs were calculated by extracting diagnosis-related group codes and then applying 2014 Medicare reimbursement rates. A Markov model evaluated qualityadjusted life years (QALYs) for both treatment groups. Univariate and multivariate sensitivity analyses were conducted to test the stability of the model. The model adopted both societal and health system perspectives and applied a 3% annual discount rate.

RESULTS: The cTDR costs $1687 more than anterior cervical discectomy and fusion (ACDF) over 5 years. In contrast, cTDR had $34 377 less productivity loss compared with ACDF. There was a significant difference in the return-to-work rate (81.6% compared with 65.4% for cTDR and ACDF, respectively; P = .029). From a societal perspective, the incremental cost-effective ratio (ICER) for cTDR was 2$165 103 per QALY. From a health system perspective, the ICER for cTDR was $8518 per QALY. In the sensitivity analysis, the ICER for cTDR remained below the US willingness-to-pay threshold of $50 000 per QALY in all scenarios (2$225 816 per QALY to $22 071 per QALY).

CONCLUSION: This study is the first to report the comparative cost-effectiveness of cTDR vs ACDF for 2-level degenerative disc disease at 5 years. The authors conclude that, because of the negative ICER, cTDR is the dominant modality.

A Pilot Cost-Effectiveness Analysis of Treatments in Newly Diagnosed High-Grade Gliomas: The Example of 5-Aminolevulinic Acid Compared With White-Light Surgery

5-ALA-induced fluorescence behavior of reactive tissue changes following glioblastoma treatment with radiation and chemotherapy

Neurosurgery 76:552–562, 2015

High-grade gliomas are aggressive, incurable tumors characterized by extensive diffuse invasion of the normal brain parenchyma. Novel therapies at best prolong survival; their costs are formidable and benefit is marginal. Economic restrictions thus require knowledge of the cost-effectiveness of treatments. Here, we show the cost-effectiveness of enhanced resections in malignant glioma surgery using a well-characterized tool for intraoperative tumor visualization, 5-aminolevulinic acid (5-ALA).

OBJECTIVE: To evaluate the cost-effectiveness of 5-ALA fluorescence-guided neurosurgery compared with white-light surgery in adult patients with newly diagnosed high-grade glioma, adopting the perspective of the Portuguese National Health Service.

METHODS: We used a Markov model (cohort simulation). Transition probabilities were estimated with the use of data from 1 randomized clinical trial and 1 noninterventional prospective study. Utility values and resource use were obtained from published literature and expert opinion. Unit costs were taken from official Portuguese reimbursement lists (2012 values). The health outcomes considered were quality-adjusted life-years, lifeyears, and progression-free life-years. Extensive 1-way and probabilistic sensitivity analyses were performed.

RESULTS: The incremental cost-effectiveness ratios are below €10 000 in all evaluated outcomes, being around €9100 per quality-adjusted life-year gained, €6700 per life-year gained, and €8800 per progression-free life-year gained. The probability of 5-ALA fluorescence-guided surgery cost-effectiveness at a threshold of €20000 is 96.0% for quality-adjusted life-year, 99.6% for life-year, and 98.8% for progression-free life-year.

CONCLUSION: 5-ALA fluorescence-guided surgery appears to be cost-effective in newly diagnosed high-grade gliomas compared with white-light surgery. This example demonstrates cost-effectiveness analyses for malignant glioma surgery to be feasible on the basis of existing data.

Surgical Management of Trigeminal Neuralgia: Use and Cost-Effectiveness From an Analysis of the Medicare Claims Database

SnapShotPNGOID_38_20121112T070408_110023

Neurosurgery 75:220–226, 2014

Trigeminal neuralgia is a relatively common neurosurgical pathology with multiple management options. Microvascular decompression (MVD) is nonablative and is considered the gold standard. However, stereotaxic radiosurgery (SRS) and percutaneous stereotaxic rhizotomy (PSR) are 2 noninvasive but ablative options that have rapidly gained support.

OBJECTIVE: To use Medicare claims data in conjunction with a literature review to assess the usage, effectiveness, and cost-effectiveness of the 3 different invasive treatments for trigeminal neuralgia.

METHODS: All of the claims of trigeminal neuralgia treatment were extracted from the 2011 5% Inpatient and Outpatient Limited Data Set. Current Procedural Terminology, 4th Edition/International Classification of Diseases, Ninth Revision codes for the 3 different surgical treatment modalities were used to further classify these claims. Kaplan-Meier survival curves in key articles were used to calculate quality-adjusted life years and costeffectiveness for each procedure.

RESULTS: A total of 1582 claims of trigeminal neuralgia were collected. Ninety-four (6%) patients underwent surgical intervention. Forty-eight (51.1%) surgical patients underwent MVD, 39 (41.5%) underwent SRS, and 7 (7.4%) underwent PSR. The average weighted costs for MVD, SRS, and PSR were $40 434.95, $38 062.27, and $3910.64, respectively. The qualityadjusted life yearswere 8.2 forMVD, 4.9 for SRS, and 6.5 for PSR. The cost per quality-adjusted life year was calculated as $4931.1, $7767.8, and $601.64 for MVD, SRS, and PSR, respectively.

CONCLUSION: This study shows that the most frequently used surgical management of trigeminal neuralgia is MVD, followed closely by SRS. PSR, despite being the most cost-effective, is by far the least utilized treatment modality.

Cost-effectiveness analysis: comparing single-level cervical disc replacement and single-level anterior cervical discectomy and fusion

CDR

J Neurosurg Spine 19:546–554, 2013

In recent years, there has been increased interest in the use of cervical disc replacement (CDR) as an alternative to anterior cervical discectomy and fusion (ACDF). While ACDF is a proven intervention for patients with myelopathy or radiculopathy, it does have inherent limitations. Cervical disc replacement was designed to preserve motion, avoid the limitations of fusion, and theoretically allow for a quicker return to activity. A number of recently published systematic reviews and randomized controlled trials have demonstrated positive clinical results for CDR, but no studies have revealed which of the 2 treatment strategies is more cost-effective. The purpose of this study was to evaluate the cost-effectiveness of CDR and ACDF by using the power of decision analysis. Additionally, the authors aimed to identify the most critical factors affecting procedural cost and effectiveness and to define thresholds for durability and function to focus and guide future research.

Methods. The authors created a surgical decision model for the treatment of single-level cervical disc disease with associated radiculopathy. The literature was reviewed to identify possible outcomes and their likelihood following CDR and ACDF. Health state utility factors were determined from the literature and assigned to each possible outcome, and procedural effectiveness was expressed in units of quality-adjusted life years (QALYs). Using ICD-9 procedure codes and data from the Nationwide Inpatient Sample, the authors calculated the median cost of hospitalization by multiplying hospital charges by the hospital-specific cost-to-charge ratio. Gross physician costs were determined from the mean Medicare reimbursement for each current procedural terminology (CPT) code. Uncertainty as regards both cost and effectiveness numbers was assessed using sensitivity analysis.

Results. In the reference case, the model assumed a 20-year duration for the CDR prosthesis. Cervical disc replacement led to higher average QALYs gained at a lower cost to society if both strategies survived for 20 years ($3042/QALY for CDR vs $8760/QALY for ACDF). Sensitivity analysis revealed that CDR needed to survive at least 9.75 years to be considered a more cost-effective strategy than ACDF. Cervical disc replacement becomes an acceptable societal strategy as the prosthesis survival time approaches 11 years and the $50,000/QALY gained willingness-to-pay threshold is crossed. Sensitivity analysis also indicated that CDR must provide a utility state of at least 0.796 to be cost-effective.

Conclusions. Both CDR and ACDF were shown to be cost-effective procedures in the reference case. Results of the sensitivity analysis indicated that CDR must remain functional for at least 14 years to establish greater costeffectiveness than ACDF. Since the current literature has yet to demonstrate with certainty the actual durability and long-term functionality of CDR, future long-term studies are required to validate the present analysis.

Cost-effectiveness of transforaminal lumbar interbody fusion for Grade I degenerative spondylolisthesis

J Neurosurg Spine 15:138–143, 2011. DOI: 10.3171/2011.3.SPINE10562

Transforaminal lumbar interbody fusion (TLIF) for spondylolisthesis-associated back and leg pain is associated with improvement in pain, disability, and quality of life. However, given the rising health care costs associated with spinal fusion procedures and varying results of recent cost-utility studies, the cost-effectiveness of TLIF remains unclear. The authors set out to assess the comprehensive costs of TLIF at their institution and to determine its cost-effectiveness in the treatment of degenerative spondylolisthesis.

Methods. Forty-five patients undergoing TLIF for Grade I degenerative spondylolisthesis–associated back and leg pain after 6–12 months of conservative therapy were included. The authors assessed the 2-year back pain visual analog scale (VAS) score, leg pain VAS score, Oswestry Disability Index, and total back-related medical resource utilization, missed work, and health-state values (quality-adjusted life years [QALYs], calculated from EQ-5D with US valuation). Two-year resource use was multiplied by unit costs based on Medicare national allowable payment amounts (direct cost), and patient and caregiver workday losses were multiplied by the self-reported gross-of-tax wage rate (indirect cost). The mean total 2-year cost per QALY gained after TLIF was assessed.

Results. Compared with preoperative health states reported after at least 6 months of medical management, a significant improvement in back pain VAS score, leg pain VAS score, and Oswestry Disability Index was observed 2 years after TLIF, with a mean 2-year gain of 0.86 QALYs. The mean ± SD total 2-year cost of TLIF was $36,836 ± $11,800 (surgery cost, $21,311 ± $2800; outpatient resource utilization cost, $3940 ± $2720; indirect cost, $11,584 ± $11,363). Transforaminal lumbar interbody fusion was associated with a mean 2-year cost per QALY gained of $42,854.

Conclusions. Transforaminal lumbar interbody fusion improved pain, disability, and quality of life in patients with degenerative spondylolisthesis–associated back and leg pain. The total cost per QALY gained for TLIF was $42,854 when evaluated 2 years after surgery with Medicare fees, suggesting that TLIF is a cost-effective treatment of lumbar spondylolisthesis.

Cost effectiveness of disc prosthesis versus lumbar fusion in patients with chronic low back pain: randomized controlled trial with 2-year follow-up

Eur Spine J (2011) 20:1001–1011. DOI 10.1007/s00586-010-1607-3

This  randomized  controlled  health  economic study assesses the cost-effectiveness of the concept of total disc replacement (TDR) (Charité/Prodisc/Maverick) when compared with the concept of instrumented lumbar fusion (FUS) [posterior lumbar fusion (PLF) /posterior lumbar interbody fusion (PLIF)]. Social and healthcare perspectives after 2 years are reported.

In all, 152 patients were randomized  to  either  TDR  (n = 80)  or  lumbar  FUS (n = 72). Cost to society (total mean cost/patient, Swedish kronor = SEK,  standard  deviation)  for  TDR  was  SEK 599,560  (400,272),  and  for  lumbar  FUS  SEK  685,919 (422,903) (ns). The difference was not significant: SEK 86,359 (-45,605  to 214,332). TDR was significantly less costly from a healthcare perspective, SEK 22,996 (1,202 to 43,055). Number of days on sick leave among those who returned to work was 185 (146) in the TDR group, and 252 (189) in the FUS group (ns). Using EQ-5D, the total gain in quality adjusted life years (QALYs) over 2 years was 0.41 units for TDR and 0.40 units for FUS (ns). Based on EQ- 5D,  the  incremental  cost-effectiveness  ratio  (ICER)  of using TDR instead of FUS was difficult to analyze due to the ‘‘non-difference’’ in treatment outcome, which is why cost/QALY  was  not  meaningful  to  define. Using  cost- effectiveness probabilistic analysis, the net benefit (with CI) was found to be SEK 91,359 (-73,643  to 249,114) (ns). We used the currency of 2006 where 1 EURO = 9.26 SEK and 1 USD = 7.38 SEK.

It was not possible to state whether TDR or FUS is more cost-effective after 2 years. Since  disc replacement and lumbar fusion are based on different conceptual approaches, it is important to follow these results over time.

Economic impact of improving outcomes of lumbar discectomy

The Spine Journal 10 (2010) 108–116.doi:10.1016/j.spinee.2009.08.453

BACKGROUND: Lumbar discectomy is usually a successful operation with a relatively low cost. Potential adjunctive procedures, such as repairing the anulus fibrosus or nucleus replacements, necessitate a cost-benefit analysis.

PURPOSE: This economic analysis was performed to understand the potential value of advanced implantable technologies designed to improve outcomes after discectomy.

STUDY DESIGN/SETTING: Using an insurance claims–based database, the economics of lessthan- favorable outcomes after lumbar discectomy were studied. Estimates of improved clinical outcomes because of adjunctive surgical procedural items were modeled.

PATIENT SAMPLE: Using Current Procedural Terminology (CPT-4) codes and International Classification of Diseases, Clinical Modification procedure codes (ICD-9 CM), all lumbar discectomy patients were identified in a 6-month period from a large, 2002, commercially available claims-based data set representing 3.1 million insured lives.

OUTCOME MEASURES: Not applicable.

METHODS: Longitudinal data analysis from 3 years (2002–2004) of the database was performed for evidence of claims after the insured’s discectomy (up to 18 months post) as a utilization estimate of surgical and medical treatment resultant of less-than-favorable outcomes. Incidence and cost of secondary operations, medical management, and complications were determined. Using these inputs, an economic model was generated to estimate the effect of improvement in discectomy outcomes.

RESULTS: Of the 494 patients who had a discectomy within a 6-month period, 137 (28%) had subsequent claims that suggested the outcome was less than favorable within 18 months. Patients whose insurance claims included codes for a second operation (n552 patients with 56 operations; 11%) and patients being medically/nonsurgically managed (n585, 17%) were studied. Average reimbursed charges incurred (2006 dollars) of repeated discectomy (80% of cases) was $6,907 and for arthrodesis (20% of cases) was $24,375. Average additional medical treatment cost to diagnose or manage poor outcome requiring another surgery was $3,365. Procedure-related complications within 40 days of surgery were evident in 15% of the group; with additional average cost to manage of $3,939.

CONCLUSIONS: Substantial cost associated with poor discectomy outcomes is often overlooked or underappreciated. Surgical technologies that can improve outcomes of discectomy by 50% to 70% thus improving patient quality of life can be overall cost-neutral between $971 and $1,655 additionally per patient.

Understanding inconsistencies in patient-reported outcomes after spine treatment: response shift phenomena

Not uncommonly, spine surgeons and physiatrists note a mismatch between patient-reported outcome measures, where one measure might indicate a good outcome and another indicates an inferior outcome after spine treatment. This may be the result of patient characteristics that lead to changes in internal standards, values, and conceptualization of their own health-related quality of life. This can result in a ‘‘moving goal post’’ when a self-report outcome measure is used for prepost comparisons. These ‘‘response shifts’’ may obfuscate relevant changes of interest to clinicians and are meaningful and worthy of study in and of themselves.

PURPOSE: To provide a background on response shift with an emphasis on distinctions relevant to spinal interventions, both surgical and nonsurgical. To describe current methods for detecting and investigating response shift phenomena, and to propose specific hypotheses that can be tested in collaborative research. METHODS AND RESULTS: Two types of methods will be briefly described: methods that require new data collection; and methods that use recent statistical and technical advances to implement secondary analysis of existing data. Two specific testable hypotheses for spinal disorders are suggested along with suggested methods for testing these hypotheses. CONCLUSIONS: A response shift will cause the patient to use the same functional outcome report measure differently pre- and posttreatment. Response shift phenomena are likely to affect the measurement properties of standard spine outcome measures and to obfuscate differences between treatments in clinical trials and cost-effectiveness studies. They point to a need for developing strategies in clinical practice to manage response shifts so that they enhance patient well-being.