An economic model of one-level lumbar arthroplasty versus fusion

Comparison of value per operative time between anterior lumbar interbody fusion and lumbar disc arthroplasty: A propensity score-matched analysis

Context

Despite the growing evidence demonstrating its effectiveness, lumbar disc arthroplasty (LDA) rates have not increased significantly in recent years. A likely contributing factor is uncertainties related to reimbursement and insurers' denial of coverage due to fear of late complications, reoperations, and unknown secondary costs. However, no prior study has compared the physician reimbursement rates of lumbar fusion and LDA.

Aim

The aim of this study was to compare the relative value units (RVUs) per min as well as 30-day readmission, reoperation, and morbidity rates between anterior lumbar interbody fusion (ALIF) and LDA.

Settings and Design

This was a retrospective cohort study.

Subjects and Methods

The current study utilizes data obtained from the National Surgical Quality Improvement Program database. Patients who underwent ALIF or LDA between 2011 and 2019 were included in the study.

Statistical Analysis Used

Propensity score matching analysis was performed according to demographic characteristics and comorbidities. Matched groups were compared through Fisher's exact test and independent t-test for categorical and continuous variables, respectively.

Results

Five hundred and two patients who underwent ALIF were matched with 591 patients who underwent LDA. Mean RVUs per min was significantly higher for ALIF compared to LDA. ALIF was associated with a significantly higher 30-day morbidity rate compared to LDA, while readmission and reoperation rates were statistically similar. ALIF was also associated with higher frequencies of deep venous thrombosis (DVT) and blood transfusions.

Conclusions

ALIF is associated with significantly higher RVUs per min compared to LDA. ALIF is also associated with higher rates of 30-day morbidity, DVT, and blood transfusions, while readmission and reoperation rates were statistically similar.

Comparison of therapies in lumbar degenerative disc disease: a network meta-analysis of randomized controlled trials

Aim: To compare the efficacy and safety of total disc replacement, lumbar fusion, and conservative care in the treatment of single-level lumbar degenerative disc disease (DDD). Materials & methods: A network meta-analysis was conducted to determine the relative impact of lumbar DDD therapies on Oswestry Disability Index (ODI) success, back pain score, patient satisfaction, employment status, and reoperation. Odds ratios or mean differences and 95% credible intervals were reported. Results: Six studies were included (1417 participants). Overall, the activL total disc replacement device had the most favorable results for ODI success, back pain, and patient satisfaction. Results for employment status and reoperation were similar across therapies. Conclusion: activL substantially improves ODI success, back pain, and patient satisfaction compared with other therapies for single-level lumbar DDD.

The Impact of High-Frequency Chest Wall Oscillation on Healthcare Use in Patients with Neuromuscular Diseases

RATIONALE

People with neuromuscular disease frequently have difficulty clearing pulmonary secretions, which leads to pneumonia and respiratory failure. High-frequency chest wall oscillation (HFCWO) is one intervention used to facilitate secretion clearance.

OBJECTIVES

The objective of this study was to determine if HFCWO therapy leads to improved outcomes as measured by lower healthcare use for patients who have a chronic neuromuscular disease.

METHODS

We performed a cohort study comparing healthcare claims before and after initiation of HFCWO. Data were obtained from two large databases of commercial insurance claims. Study subjects were commercial insurance members with an International Classification of Diseases, Ninth Revision, code for a neuromuscular disease and a claim for HFCWO between 2007 and 2011. The study included both children and adults.

MEASUREMENTS AND MAIN RESULTS

There were 426 patients in this study. Their mean age was 29.9 ± 22 years. Total medical costs per member per month decreased by $1,949 (18.6%) after initiation of HFCWO (P = 0.002). Inpatient admission costs decreased by $2,392 (41.7%) (P = 0.001), and pneumonia costs decreased by $514 (18.1%) (P = 0.015). To account for the possibilities of misclassification based on diagnosis and bias due to loss to follow-up, we compared outcomes between those lost to follow-up and those not, and we found similar results.

CONCLUSIONS

Total medical costs, hospitalizations, and pneumonia claims were less after than before initiation of HFCWO in a broad group of patients with neuromuscular disease. Subject to the limitations that administrative data did not capture how HFCWO was used and that HFCWO may be a marker of generally better care, our findings lend support to the routine use of this intervention in the care of patients with neuromuscular diseases.

Barriers to and Budget Impact of Lumbar Total Disc Replacement Utilization

: Evidence on the favorable efficacy, safety, and cost effectiveness of lumbar total disc replacement (TDR) compared with fusion for lumbar degenerative disc disease is mounting; however, a key barrier identified for TDR utilization is lack of coverage by US health insurers. Although economic considerations in a fee-for-service model should not be a determining factor in patient access, concerns regarding the budget impact of lumbar TDR surgery may unfortunately underlie coverage decisions. On the basis of the data available and economic modeling, the panel agreed that there is no indication that there would be a dramatic increase in patients seeking lumbar TDR. Considering several possible scenarios on potential growth in TDR utilization with coverage, as well as growth in the overall surgical pool of patients, economic modeling demonstrated that adoption of lumbar TDR would result in minimal or no budget impact for commercial insurance plans. Considering these model results and the economic literature, the panel concluded that adopting lumbar TDR within a coverage policy is expected to remain cost neutral for the insurer.

Defining the Ideal Lumbar Total Disc Replacement Patient and Standard of Care

: Lumbar total disc replacement, now in use since 2004, was determined by the panel to be a standard of care for the treatment of symptomatic single-level lumbar degenerative disc disease in the active patient subpopulation as outlined by the investigational device exemption study criteria. The large body of evidence supporting this statement, including surgeons' experiences, was presented and discussed. Consensus statements focusing on decision-making criteria reflected that efficacy, long-term safety, clinical outcomes with validated measures, and cost-effectiveness should form the basis of decision-making by payers. Diagnostic challenges with lumbar degenerative disc disease patients were discussed among the panel, and it was concluded that although variably used among surgeons, reliable tools exist to appropriately diagnose discogenic back pain.

A cost-utility analysis of Dynesys dynamic stabilization versus instrumented fusion for the treatment of degenerative lumbar spine diseases

BACKGROUND

Symptomatic chronic low back and leg pain resulting from lumbar spine degenerative disorders is highly prevalent in China, and for some patients, surgery is the final option for improvement. Several techniques for spinal non-fusion have been introduced to reduce the side-effects of fusion methods and hasten postoperative recovery. In this study, the authors have evaluated the cost-effectiveness of Dynesys posterior dynamic stabilization system (DY) compared with lumbar fusion techniques in the treatment of single-level degenerative lumbar spinal conditions.

METHODS

A total of 221 patients undergoing single-level elective primary surgery for degenerative lumbar pathology were included. 2-Year postoperative health outcomes of Visual Analogue Scale (VAS) for back and leg pain, Oswestry Disability Index (ODI), 36-Item Short Form Health Survey (SF-36) and EuroQol-5 Dimensions (EQ-5D) questionnaires were recorded. 2-Year back-related medical resource use, missed work, and health-state values (Quality-adjusted life-year [QALY]) were assessed. Cost-effectiveness was determined by the incremental cost per QALY gained.

RESULTS

At each follow-up point, both cohorts were associated with significant improvements in VAS scores, ODI, SF-36 scores and EQ-5D QALY scores, which persisted at the 2-year evaluation. The 2-year total mean cost per patient were significantly lower for Dynesys system ($20,150) compared to fusion techniques ($25,581, $27,862 and $27,314, respectively) (P < 0.001). Using EQ-5D, the mean cumulative 2-year QALYs gained were statistically equivalent between the four groups (0.28, 0.27, 0.30 and 0.30 units, respectively) (P = 0.74). Results indicate that patients implanted with the DY system derive lower total costs and more utility, on average, than those treated with fusion.

CONCLUSIONS

The Dynesys dynamic stabilization system is cost effective compared to instrumented lumbar fusion for treatment of single-level degenerative lumbar disorders. It is not possible to state whether DY or lumbar fusion is more cost-effective after 2 years.

Evaluation of Aesculap Implant Systems activl Artificial Disc for the treatment of degenerative disc disease

INTRODUCTION

A primary cause of chronic low back pain and disability is lumbar degenerative disc disease (DDD). Surgical treatments are available for DDD including fusion or lumbar total disc replacement (TDR). Lumbar TDR is performed as a motion-preserving alternative to lumbar fusion. There are several marketed lumbar TDR devices including the Aesculap Implant Systems activL Artificial Disc, Charité Artificial Disc and the ProDisc-L Total Disc Replacement. Areas covered: Considering the various surgical options by which lumbar DDD can be managed, here we evaluate the biologic and biomechanical benefits and concerns of the Aesculap activL Artificial Disc. We review the use of the activL Artificial Disc compared to other lumbar TDRs and an alternative to fusion for skeletally mature patients diagnosed with isolated, symptomatic DDD. Expert commentary: Short-term follow-up studies suggest that under the right circumstances and precise patient selection, lumbar TDR with the Aesculap activL Artificial Disc is a safe and effective alternative to lumbar fusion. Long-term clinical data will provide information about the potential for adjacent level disease, effects of implant wear, and indications for revision surgery. Future clinical and biomechanical studies, as well as device-specific long-term outcome and comparison studies, will assist surgical decision making.

A systematic review and meta-analysis of outcomes in hybrid constructs for multi-level lumbar degenerative disc disease

A systematic review and meta-analysis was performed to assess the effect of hybrid constructs which involve a total disc arthroplasty (TDA) with stand-alone anterior lumbar interbody fusion (ALIF) versus non-hybrid constructs including multi-level TDA, multi-level transforaminal lumbar interbody fusion (TLIF) with posterior transpedicular fixation or multi-level stand-alone ALIF as a surgical intervention for degenerative disc disease (DDD) in the lumbar spine. Primary outcomes analysed included the Oswestry Disability Index (ODI) and the Visual Analogue Scale (VAS) for back pain. A systematic search of Medline, Embase, Pubmed, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews and Google Scholar was undertaken by two separate reviewers and a meta-analysis of the outcomes was performed. Three studies met our search criteria. When comparing hybrid constructs to multi-level TDA or lumbar fusion (LF) improvements in back pain were found with a VAS back pain score reduction of 1.38 (P<0.00001) postoperatively and a VAS back pain score reduction of 0.99 points (P=0.0006) at 2-years follow-up. Results so far slightly favour clinically significant improved VAS back pain score outcomes postoperatively and at 2-years follow-up for hybrid constructs in multi-level lumbar DDD of the spine when compared with non-hybrid multi-level LF or TDA. It cannot however be concluded that a hybrid construct is superior to multi-level LF or TDA based on this meta-analysis. The results highlight the need for further prospective studies to delineate best practice in the management of degenerative disc disease of the lumbar spine.

Lumbar Total Disc Replacement for Discogenic Low Back Pain: Two-year Outcomes of the activL Multicenter Randomized Controlled IDE Clinical Trial

STUDY DESIGN

A prospective, multicenter, randomized, controlled, investigational device exemption (IDE) noninferiority trial.

OBJECTIVE

The aim of this study was to evaluate the comparative safety and effectiveness of lumbar total disc replacement (TDR) in the treatment of patients with symptomatic degenerative disc disease (DDD) who are unresponsive to nonsurgical therapy.

SUMMARY OF BACKGROUND DATA

Lumbar TDR has been used to alleviate discogenic pain and dysfunction while preserving segmental range of motion and restoring stability. There is a paucity of data available regarding the comparative performance of lumbar TDR.

METHODS

Patients presenting with symptomatic single-level lumbar DDD who failed at least 6 months of nonsurgical management were randomly allocated (2:1) to treatment with an investigational TDR device (activL, n = 218) or FDA-approved control TDR devices (ProDisc-L or Charité, n = 106). The hypothesis of this study was that a composite effectiveness outcome at 2 years in patients treated with activL would be noninferior (15% delta) to that in controls.

RESULTS

The primary composite endpoint of this study was met, which demonstrated that the activL TDR was noninferior to control TDR (P < 0.001). A protocol-defined analysis of the primary composite endpoint also confirmed that activL was superior to controls (P = 0.02). Radiographic success was higher with activL versus controls (59% vs. 43%; P < 0.01). Mean back pain severity improved by 74% with activL and 68% with controls. Oswestry Disability Index scores decreased by 67% and 61% with activL and controls, respectively. Patient satisfaction with treatment was over 90% in both groups at 2 years. Return to work was approximately 1 month shorter (P = 0.08) with activL versus controls. The rate of device-related serious adverse events was lower in patients treated with activL versus controls (12% vs. 19%; P = 0.13). Surgical reintervention rates at the index level were comparable (activL 2.3%, control 1.9%).

CONCLUSION

The single-level activL TDR is safe and effective for the treatment of symptomatic lumbar DDD through 2 years.

LEVEL OF EVIDENCE

2.

Viscoelastic Disc Arthroplasty Provides Superior Back and Leg Pain Relief in Patients with Lumbar Disc Degeneration Compared to Anterior Lumbar Interbody Fusion

BACKGROUND

Lumbar disc degeneration (LDD) is one of the most frequently diagnosed spinal diseases. The symptoms these disorders cause are anticipated to increase as the population in Western countries ages.

PURPOSE

Compare back and leg pain alleviation in patients with LDD and a viscoelastic disc prosthesis documented in the SWISSspine registry versus patients with anterior lumbar interbody fusion documented in the Spine Tango registry.

STUDY DESIGN

Prospectively collected clinical and outcome data in two independent spine registries. Outcome Measures were back and leg pain relief on 0 to 10 numerical rating scales.

MATERIALS AND METHODS

The analysis included a single surgeon series of 48 patients with viscoelastic total disc replacement (VTDR) from the SWISSspine registry which were compared to 131 patients with anterior lumbar interbody fusion (ALIF) from the Spine Tango registry. Two linear multivariate regression models were built to assess the associations of patient characteristics with back and leg pain relief. The following covariates were included in the models: patient age and sex, disc herniation as additional diagnosis, number of treated segments, level of treated segment, treatment type (VTDR, ALIF), preoperative back and leg pain levels and follow-up interval.

RESULTS

Both models showed VTDR to be associated with significantly higher back (2.76 points; 95% confidence interval (CI) 1.78 - 3.73; p < 0.001) and leg pain (2.12 points; 95% CI 1.12 to 3.13; p < 0.001) relief than ALIF. Other influential factors for higher back pain relief were female sex compared with male sex (1.03 additional points; 95% CI 0.27 to 1.78; p = 0.008), monosegmental surgery compared with bisegmental surgery (1.02 additional points; 95% CI 0.21 to 1.83; p = 0.014), and higher back pain at baseline (0.87 points additional pain relief per level of preoperative back pain; 95% CI 0.70 to 1.03; p < 0.001). Other influential factors for leg pain relief were monosegmental surgery (0.93 additional points; 95% CI 0.10 to 1.77; p = 0.029) and higher leg pain at baseline (0.83 points additional pain relief per level of preoperative leg pain; 95% CI 0.70 to 0.96). In both models the L3/4 segment showed 2.36 points (95% CI -4.27 to -0.45; p = 0.016) and 3.69 points (95% CI -5.66 to -1.71; p < 0.001) less pain relief than L5/S1.

DISCUSSION

Significantly higher back and leg pain relief were observed after viscoelastic total disc replacement in comparison with anterior lumbar interbody fusion. The new less rigid materials used in the second generation total disc replacements (TDRs) may make artificial disc replacement an increasingly attractive option for patients with degenerative lumbar disc disease. Further controlled and long-term follow-up studies are required for more detailed comparisons of the outcomes of these types of disc implants. The Freedom Lumbar Disc is limited by U.S. federal law to investigational use only.

ISASS Policy Statement - Lumbar Artificial Disc

PURPOSE

The primary goal of this Policy Statement is to educate patients, physicians, medical providers, reviewers, adjustors, case managers, insurers, and all others involved or affected by insurance coverage decisions regarding lumbar disc replacement surgery.

PROCEDURES

This Policy Statement was developed by a panel of physicians selected by the Board of Directors of ISASS for their expertise and experience with lumbar TDR. The panel's recommendation was entirely based on the best evidence-based scientific research available regarding the safety and effectiveness of lumbar TDR.

Clinical applications of naturally derived biopolymer-based scaffolds for regenerative medicine

Naturally derived polymeric biomaterials, such as collagens, silks, elastins, alginates, and fibrins are utilized in tissue engineering due to their biocompatibility, bioactivity, and tunable mechanical and degradation kinetics. The use of these natural biopolymers in biomedical applications is advantageous because they do not release cytotoxic degradation products, are often processed using environmentally-friendly aqueous-based methods, and their degradation rates within biological systems can be manipulated by modifying the starting formulation or processing conditions. For these reasons, many recent in vivo investigations and FDA-approval of new biomaterials for clinical use have utilized natural biopolymers as matrices for cell delivery and as scaffolds for cell-free support of native tissues. This review highlights biopolymer-based scaffolds used in clinical applications for the regeneration and repair of native tissues, with a focus on bone, skeletal muscle, peripheral nerve, cardiac muscle, and cornea substitutes.

Five-year results of lumbar disc prostheses in the SWISSspine registry

PURPOSE

The Swiss Federal Office of Public Health demanded a nationwide HTA registry for lumbar total disc arthroplasty (TDA), to decide about its reimbursement. The goal of the SWISS spine registry is to generate evidence about the safety and efficiency of lumbar TDA.

METHODS

Two hundred forty-eight cases treated between 3-2005 and 6-2006, who were eligible for the 5-year follow-up were included in the study. Follow-up rates for 3-6 months, 1, 2 and 5 years were 85.9, 77.0, 44.0 and 51.2 %, respectively. Outcome measures were back and leg pain, medication consumption, quality of life, intraoperative and postoperative complication and revision rates. Additionally, segmental mobility, ossification, adjacent and distant segment degeneration were analysed at the 5-year follow-up.

RESULTS

There was a significant, clinically relevant and lasting reduction of back (preop/postop 73/29 VAS points) and leg pain (preop/postop VAS 55/22) and a consequently decreased analgesics consumption and quality of life improvement (preop/postop 0.30/0.76 EQ-5D score points) until 5 years after surgery. The rates for intraoperative and early postoperative complications were 4.4 and 3.2 %, respectively. The overall complication rate during five postoperative years was 23.4 %, and the adjacent segment degeneration rate was 10.7 %. In 4.4 % of patients, a revision surgery was performed. Cumulative survivorship probability for a revision/re-intervention-free 5-year postoperative course was 90.4 %. At the 5-year follow-up, the average range of motion of the mobile segments (86.8 %) was 9.7°. In 43.9 % of patients, osteophytes at least potentially affecting the range of motion were seen.

CONCLUSIONS

Lumbar TDA appeared as efficient in long-term pain alleviation, consequent reduction of pain medication consumption and improvement of quality of life. The procedure also appeared sufficiently safe, but surgeons have to be aware of a list of potential adverse events. The outcome is stable over the 5-year postoperative period. The vast majority of treated segments remained mobile after 5 years, although almost half of patients showed osteophytes.

Current status of bone graft options for anterior interbody fusion of the cervical and lumbar spine

Anterior cervical discectomy and fusion (ACDF) and anterior lumbar interbody fusion (ALIF) are common surgical procedures for degenerative disc disease of the cervical and lumbar spine. Over the years, many bone graft options have been developed and investigated aimed at complimenting or substituting autograft bone, the traditional fusion substrate. Here, we summarise the historical context, biological basis and current best evidence for these bone graft options in ACDF and ALIF.

Cost-effectiveness of lumbar artificial intervertebral disc replacement: driven by the choice of comparator

BACKGROUND

Lower back pain is a common and costly condition in Australia. This paper aims to conduct an economic evaluation of lumbar artificial intervertebral disc replacement (AIDR) compared with lumbar fusion for the treatment of patients suffering from significant axial back pain and/or radicular (nerve root) pain, secondary to disc degeneration or prolapse, who have failed conservative treatment.

METHODS

A cost-effectiveness approach was used to compare costs and benefits of AIDR to five fusion approaches. Resource use was based on Medicare Benefits Schedule claims data and expert opinion. Effectiveness and re-operation rates were based on published randomized controlled trials. The key clinical outcomes considered were narcotic medication discontinuation, achievement of overall clinical success, achievement of Oswestry Disability Index success and quality-adjusted life-years gained.

RESULTS

AIDR was estimated to be cost-saving compared with fusion overall ($1600/patient); however, anterior lumbar interbody fusion and posterolateral fusion were less costly by $2155 and $807, respectively. The incremental cost-effectiveness depends on the outcome considered and the comparator.

CONCLUSIONS

AIDR is potentially a cost-saving treatment for lumbar disc degeneration, although longer-term follow-up data are required to substantiate this claim. The incremental cost-effectiveness depends on the outcome considered and the comparator, and further research is required before any firm conclusions can be drawn.

Is anterior cervical fusion with a porous tantalum implant a cost-effective method to treat cervical disc disease with radiculopathy?

STUDY DESIGN

Retrospective cost-effectiveness analysis.

OBJECTIVE

To determine the relative cost-effectiveness of anterior cervical discectomy with fusion (ACDF) using a porous tantalum implant compared with autograft with plating, for single-level cervical disc disease with radiculopathy.

SUMMARY OF BACKGROUND DATA

ACDF with autograft as an interbody spacer is a generally accepted method to treat degenerated cervical discs with radiculopathy. Concerns about donor site morbidity and the structural characteristics of autograft stimulated investigations of alternative materials. Techniques may differ in their operative risks, complications, outcomes, and resource use.

METHODS

A retrospective review of clinical outcomes and total cost of illness for 5 years postsurgery was performed for 61 consecutive patients enrolled for this study. Twenty-eight patients were treated with single-level ACDF using either a stand-alone, porous tantalum implant, without graft inside the implant, and 33 patients received autograft and plating. A cost-effectiveness analysis comparing the 2 ACDF treatment methods was conducted. This article reports clinical assessments, quality adjusted life years gained, and an incremental cost-effectiveness ratio analysis.

RESULTS

Patients in both cohorts reported improved clinical outcomes, including neck disability index, visual analogue scale, Short-Form 36, Odom's clinical assessment, and patient satisfaction at 5 years postindex surgery. The mean cost of illness for the study period, including preoperative through 5 years postoperative assessments, was 6806 per patient treated with tantalum and 10,143 per patient receiving autograft and plate. Quality-adjusted life years (QALY) gained were 9.41 and 7.14 for the tantalum and control cohorts, respectively. The cost per QALY for the tantalum group was 723 and 1420 for the control group. The incremental cost-effectiveness ratio of ACDF with a porous tantalum implant compared with ACDF with autograft and plate was -1473 per patient per year for the duration of this study.

CONCLUSION

This cost-effectiveness analysis reports favorable results for ACDF procedures utilizing a tantalum implant. The data reported suggest that using porous tantalum as a stand-alone device is less costly and more effective than autograft and plate in ACDF procedures.

Lumbar disc arthroplasty with Maverick disc versus stand-alone interbody fusion: a prospective, randomized, controlled, multicenter investigational device exemption trial

STUDY DESIGN

Randomized, controlled, multicenter, investigational device exemption trial.

OBJECTIVE

To investigate the safety and effectiveness of the first two-piece, metal-on-metal lumbar disc prosthesis for treating patients with single-level degenerative disc disease.

SUMMARY OF BACKGROUND DATA

For patients with degenerative disc disease unresponsive to conservative measures, lumbar disc arthroplasty provides an alternative to fusion designed to relieve persistent discogenic pain and maintain motion.

METHODS

After 2:1 randomization, 577 patients were treated in either the investigational group (405), receiving lumbar disc arthroplasty, or the control group (172), receiving anterior lumbar interbody fusion. Patients were evaluated preoperatively, at surgery/discharge, and at 1.5, 3, 6, 12, and 24 months after surgery. The primary study endpoint was overall success, a composite measure of safety and effectiveness as recommended by the Food and Drug Administration and defined in the protocol.

RESULTS

Both treatment groups demonstrated significant improvements compared with preoperative status. The investigational group had statistically superior outcomes (P < 0.05) at all postoperative evaluations in Oswestry Disability Index, back pain, and Short Form-36 Physical Component Summary scores as well as patient satisfaction. Investigational patients had longer surgical times (P < 0.001) and greater blood loss (P < 0.001) than did control patients; however, hospitalization stays were similar for both groups. Investigational patients had fewer implant or implant/surgical procedure-related adverse events (P < 0.001). Return-to-work intervals were reduced for investigational patients. Disc height and segmental angular motion were maintained throughout the study in the investigational group. In the investigational group, overall success superiority was found when compared to the control group as defined by the Food and Drug Administration Investigational Device Exemption protocol.

CONCLUSION

The investigational group consistently demonstrated statistical superiority versus fusion on key clinical outcomes including improved physical function, reduced pain, and earlier return to work.

Prosthetic total disk replacement--can we learn from total hip replacement?

Total lumbar disk replacement has become a routine procedure in many countries. However, discussions regarding its use are ongoing. Issues focus on patient selection, technical limitations, and avoidance or management of complications or long-term outcomes. A review of the development of this technology, since the development of the first successful implantation of a total lumbar disk prosthesis in 1984, shows an amazing analogy to the history of total hip replacement. This article is a one-to-one comparison of the evolution of total hip and total lumbar disk replacement from "skunk works" to scientific evidence.

Medicoeconomic evaluation of total disc replacement based on French National Health Care System data

INTRODUCTION

Total disc replacement (TDR) has existed since 1984 but is not covered by the French national healthcare system (Sécurité Sociale). The present study assessed clinical outcomes, and also pre-, peri- and postoperative treatment costs.

HYPOTHESIS

Surgical management of low back pain (LBP) provides medical and economic benefit.

MATERIALS AND METHODS

A prospective study recruited 19 patients in the Nice University Hospital Center (France); mean age, 41 years; 15 female. Inclusion criteria were: age less than 60 years; chronic low back pain (LBP) with single-segment discopathy; work related injuries and patients not covered under the General provision of the Sécurité Sociale were excluded. VAS, Oswestry and SF36 scores and return to work capability were analyzed. The local national health insurance branch office (Caisse Primaire d'Assurance Maladie [CPAM]) provided detailed coverage data for a 39-month period around the operation.

RESULTS

Revision surgery was required for one instance of vertebral fracture. Preoperative follow-up was 14 months, postoperative FU 21 months and the perioperative period 4 months. LBP and quality of life showed improvement. Seventy-nine percent of patients reported satisfaction, 59% returned to work, and 84% had leisure activity. Total CPAM payout (reimbursement) was €399,082. Daily sickness benefit and disability compensation were the main cost items. Mean TDR cost per patient was €6833. Mean reimbursements were 19% lower post- than preoperatively. Pre- and postoperative clinical results did not correlate, while pre- and postoperative reimbursement costs did, as did cost and postoperative clinical status (r=-0.72). Preoperative cost was a predictive factor for postoperative clinical result.

DISCUSSION

TDR achieves favorable medicoeconomic results.

LEVEL OF EVIDENCE

III: case-control study.

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

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.

Anterior interbody arthrodesis with percutaneous posterior pedicle fixation for degenerative conditions of the lumbar spine

This is a retrospective case series to evaluate clinical variables, complications and outcome of 50 patients who underwent anterior lumbar interbody fusion (ALIF) supplemented with posterior percutaneous pedicle screw fixation for degenerative conditions of the lumbar spine. Twenty-four patients underwent single-level fusion and 26 patients had a two-level fusion for a total of 76 levels fused. The mean lengths of the anterior and posterior (including repositioning) portions of the procedure were 131 and 102 min, respectively. The mean estimated blood loss for the entire procedure was 288 ml. The overall adverse event rate was 12%. The mean VAS score for leg pain, VAS score for back pain and mean ODI all improved postoperatively. This study found that ALIF using allograft bone and rhBMP-2 combined with percutaneous pedicle screw fixation had a high fusion rate and a low incidence of perioperative complications. Patient outcomes showed significant improvements in back and leg pain and physical functioning.

On total disc replacement

Low back pain consumes a large part of the community's resources dedicated to health care and sick leave. Back disorders also negatively affect the individual leading to pain suffering, decreased quality-of-life and disability. Chronic low back pain (CLBP) due to degenerative disc disease (DDD) is today often treated with fusion when conservative treatment has failed and symptoms are severe. This treatment is as successful as arthroplasty is for hip arthritis in restoring the patient's quality of life and reducing disability. Even so, there are some problems with this treatment, one of these being recurrent CLBP from an adjacent segment (ASD) after primarily successful surgery. This has led to the development of alternative surgical treatments and devices that maintain or restore mobility, in order to reduce the risk for ASD. Of these new devices, the most frequently used are the disc prostheses used in Total Disc Replacement (TDR). This thesis is based on four studies comparing total disc replacement with posterior fusion. The studies are all based on a material of 152 patients with DDD in one or two segments, aged 20-55 years that were randomly treated with either posterior fusion or TDR. The first study concerned clinical outcome and complications. Follow-up was 100% at both one and two years. It revealed that both treatment groups had a clear benefit from treatment and that patients with TDR were better in almost all outcome scores at one-year follow-up. Fusion patients continued to improve during the second year. At two-year follow-up there was a remaining difference in favour of TDR for back pain. 73% in the TDR group and 63% in the fusion group were much better or totally pain-free (n.s.), while twice as many patients in the TDR group were totally pain free (30%) compared to the fusion group (15%). Time of surgery and total time in hospital were shorter in the TDR group. There was no difference in complications and reoperations, except that seventeen of the patients in the fusion group were re-operated for removal of their implants. The second study concerned sex life and sexual function. TDR is performed via an anterior approach, an approach that has been used for a long time for various procedures on the lumbar spine. A frequent complication reported in males when this approach is used is persistent retrograde ejaculation. The TDR group in this material was operated via an extra-peritoneal approach to the retroperitoneal space, and there were no cases of persistent retrograde ejaculation. There was a surprisingly high frequency of men in the fusion group reporting deterioration in ability to have an orgasm postoperatively. Preoperative sex life was severely hampered in the majority of patients in the entire material, but sex life underwent a marked improvement in both treatment groups by the two-year follow-up that correlated with reduction in back pain. The third study was on mobility in the lumbar spinal segments, where X-rays were taken in full extension and flexion prior to surgery and at two-year follow-up. Analysis of the films showed that 78% of the patients in the fusion group reached the surgical goal (non-mobility) and that 89% of the TDR patients maintained mobility. Preoperative disc height was lower than in a normative database in both groups, and remained lower in the fusion group, while it became higher in the TDR group. Mobility in the operated segment increased in the TDR group postoperatively. Mobility at the rest of the lumbar spine increased in both treatment groups. Mobility in adjacent segments was within the norm postoperatively, but slightly larger in the fusion group. In the fourth study the health economics of TDR vs Fusion was analysed. The hospital costs for the procedure were higher for patients in the fusion group compared to the TDR group, and the TDR patients were on sick-leave two months less. In all, these studies showed that the results in the TDR group were as good as in the fusion group. Patients are more likely to be totally pain-free when treated with TDR compared to fusion. Treatment with this new procedure seems justified in selected patients at least in the short-term perspective. Long-term follow-up is underway and results will be published in due course.

Cost comparison of patients with 3-level artificial total lumbar disc replacements versus 360° fusion at 3 contiguous lumbar vertebral levels: an analysis of compassionate use at 1 site of the US investigational device exemption clinical trial

Background

We sought to evaluate the difference between hospital service costs of 2 treatment options for patients diagnosed with 3-level degenerative disc disease (DDD) in the lumbar spine. In this retrospective analysis, itemized billing records of hospital stay for patients with 3-level DDD treated with artificial disc replacement (ADR) were compared with those treated with circumferential fusion (standard of care).

Methods

Sequential 3-level DDD patients treated with either ADR (ProDisc-L; Synthes, West Chester, Pennsylvania) or circumferential fusion during the period from January 2004 to October 2005 were included. Surgeries were performed at the same hospital for all patients. The ADR-treated patients were participating in the investigational device exemption clinical trial as part of the compassionate-use arm. Patients treated with fusion at the same institution during this same time interval were evaluated. Itemized billing records were collected at least 1 year after the index surgery. Costs according to hospital service categories were compared between ADR-treated and fusion-treated patients by use of analysis of variance and multivariate statistical techniques.

Results

There were 43 consecutive patients treated for 3-level DDD between January 2004 and October 2005. Of these, 21 underwent 3-level ADR and 22 had a 3-level fusion procedure. There was a mean of 3 fewer hospital days for patients treated with ADR (4.77 ± 1.11 days) than for those treated with fusion (8.00 ± 1.82 days) (P < .0001). The cost of hospital services for ADR-treated patients was 49% less excluding instrumentation costs and 54% less when accounting for instrumentation. The pattern of cost was similar when workers’ compensation patients were analyzed separately.

Conclusions

ADR-treated 3-level patients benefited from significantly lower costs from their in-hospital stay compared with those treated by fusion. Hospital service costs were 49% (54% when instrumentation was included in the costs) less for ADR patients than for fusion patients.

L5-S1 disc replacement after two previous fusion surgeries for scoliosis

Following scoliosis surgery, lumbar motion segment degeneration below the level of fusion is not uncommon. Especially long fusions extending to the mid and lower lumbar spine increase the likelihood of degeneration of the remaining motion segments. The management for these patients is controversial and depends on the clinical presentation and level of degeneration. The increasing confidence in motion-preserving technology leads to a dilemma on whether to fuse the remaining lumbar levels or risk utilising disc arthroplasty to preserve the remaining motion segments and facilitate coronal balance in patients with previous long fusion for scoliosis. We present an interesting case of a 44-year-old lady, who underwent two-stage corrective surgery for progressive idiopathic scoliosis at the age of 22 years. In the first stage, she had T11-L3 anterior fusion, whilst in the second stage posterior fusion was done from T5 to L3. At 22 years after the initial surgery, she presented with worsening low back pain and bilateral L4 radicular symptoms. MRI scan confirmed severe disc degeneration at L3-4 and L5-S1 levels with preserved L4-5 disc. She initially underwent L3-L4 decompression and posterolateral fusion at that level, which relieved her radicular symptoms. However, she had persistent pain at the lumbosacral junction with Modic I changes. The options of an anterior L5-S1 fusion or disc replacement were considered and discussed with the patient. The disc replacement option was decided upon with the patient, as anterior fusion was judged to increase the risk of coronal imbalance. At the 1-year follow-up, she reported significant improvement in the back pain. The radiographs at 1 year showed satisfactory position and function of the artificial disc replacement. The disc was flexed laterally, accommodating the coronal balance of the spine. We conclude that L5-S1 motion segment can be preserved with artificial disc replacement in patients with previous long fusion for scoliosis surgery. The real difficulty arises when choosing between disc replacement and extension of fusion. In our patient, the disc replacement has worked well so far. However, the disc is clearly at a mechanical disadvantage, and loss of function in the mid- or long term would not be surprising.

Fusion versus disk replacement for degenerative conditions of the lumbar and cervical spine: quid est testimonium?

This article compares the outcomes following spinal fusion and disk replacement for degenerative conditions of the lumbar and cervical spine. The short-term outcomes of lumbar and cervical total disk replacement are equivalent to that following spinal fusion. Long-term follow-up studies of total disk replacement are necessary to confirm its potential benefit in reducing or preventing adjacent level degeneration. Also discussed is the philosophy of the surgical management of degenerative conditions of the lumbar and cervical spine.

National revision burden for lumbar total disc replacement in the United States: epidemiologic and economic perspectives

STUDY DESIGN

Retrospective cohort study using a nationally representative inpatient database.

OBJECTIVE

To quantify the national revision burden for lumbar total disc replacements (TDRs) in the United States following Food and Drug Administration approval, for comparison with lumbar fusion and other common orthopedic procedures, including hip and knee replacement.

SUMMARY OF BACKGROUND DATA

Previous studies of revision lumbar TDR surgery have been based on IDE studies. The epidemiology and costs of TDR revision surgery from a national perspective have not yet been reported.

METHODS

The Nationwide Inpatient Sample was used to identify primary and revision TDR and anterior fusion procedures in 2005 and 2006. Surgeries were identified in the Nationwide Inpatient Sample using ICD9-CM codes. The prevalence of TDR and fusion surgery was calculated as a function of age, gender, race, census region, primary payer class, and type of hospital. Average length of stay and total hospitalization costs were also computed for each type of procedure.

RESULTS

During the study period, there was a national total of 7172 TDR and 62,731 anterior fusion surgeries, including both primary and revisions. Overall, TDR patients were younger and had less comorbidity than fusion surgery patients. The average revision burden for lumbar TDR and anterior fusion was 11.2% and 5.8%, respectively. The average length of stay for primary lumbar TDR was significantly shorter compared to revision TDR, primary anterior fusion, and revision anterior fusion (P < 0.0001). Both the primary and the revision surgery using the TDR surgery involved significantly lower total hospital costs relative to anterior fusion surgery (P < 0.0001). Including revision, the average costs per TDR procedure were lower than anterior and posterior lumbar fusion.

CONCLUSION

Although the revision burden for TDR was significantly higher than fusion surgery, the TDR revision burden fell within the revision burden range of hip and knee replacement, which are generally considered successful and cost-effective procedures. Economically, the higher revision burden for TDRs was offset by lower costs for both the primary as well as the revision procedures relative to fusion.

Biomechanical analysis of a disc prosthesis distal to a scoliosis model

STUDY DESIGN

Biomechanical study of bovine spines.

OBJECTIVE

The purpose of this study was to perform a biomechanical test to analyze intervertebral deflections following placement of both 1 and 2 semiconstrained TDRs in the subjacent segments of a long fusion.

SUMMARY OF BACKGROUND DATA

Long-term sequela of long lumbar fusion for scoliosis include adjacent segment disease and flatback syndrome. Total disc replacement (TDR) is a viable option for the treatment of these conditions. Little data has been published regarding the placement of a TDR distal to a scoliosis fusion.

METHODS

Six thoracolumbar bovine spines (T12-S1) were instrumented from T12 to L5, with bilateral pedicle screw fixation at each level. L5-L6 and L6-S1 served as the test levels. One TDR (FlexiCore, Stryker Spine, Allendale, NJ) was initially performed adjacent to the fusion, followed by a subsequent TDR insertion at the last spinal segment. The applied load, total specimen deflection, and local transducer deflections were recorded before and after a TDR at both levels. The results were expressed as a percentage of the intact specimen. Flexion, extension, lateral bending, and torsional deflections were recorded.

RESULTS

There were no significant differences (P > 0.05) in sensor deflection observed at the L5-L6 and L6-S1 levels in the anterior and lateral transducers when compared to intact spines specimens. A similar effect was observed at the L5-L6 and L6-S1 levels in the anterior and lateral transducers when compared to intact or prior L5-L6 and intact L6-S1 constructs.

CONCLUSION

This study has shown that using the FlexiCore system at 1 and/or 2 intervertebral disc spaces caudal to a scoliosis fusion model did not significantly change the sensor deflection at the 2 segments adjacent to a scoliosis fusion construct. Future research will continue to define the clinical setting and patients best suited for management by TDR systems.

The impact of economic evaluation on quality management in spine surgery

Health care expenditures are substantially increasing within the last two decades prompting the imperative need for economic evaluations in health care. Historically, economic evaluations in health care have been carried out by four approaches: (1) the human-capital approach (HCA), (2) cost-effectiveness analysis (CEA), (3) cost-utility analysis (CUA) and (4) cost-benefit analysis (CBA). While the HCA cannot be recommended because of methodological shortcomings, CEA and CUA have been used frequently in healthcare. In CEA, costs are measured in monetary terms and health effects are measured in a non-monetary unit, e.g. number of successfully treated patients. In an attempt to develop an effectiveness measure that incorporates effects on both quantity and quality of life, so-called Quality Adjusted Life Years (QUALYs) were introduced. Contingent valuation surveys are used in cost-benefit analyses (CBA) to elicit the consumer's monetary valuations for program benefits by applying the willingness-to-pay approach. A distinguished feature of CBA is that costs and benefits are expressed in the same units of value, i.e. money. Only recently, economic evaluations have started to explore various spinal interventions particularly the very expensive fusion operations. While most of the studies used CEA or CUA approaches, CBAs are still rare. Most studies fail to show that sophisticated spinal interventions are more cost-effective than conventional treatments. In spite of the lack of therapeutic or cost-effectiveness for most spinal surgeries, there is rapidly growing spinal implant market demonstrating market imperfection and information asymmetry. A change can only be anticipated when physicians start to focus on the improvement of health care quality as documented by outcome research and economic evaluations of cost-effectiveness and net benefits.