Invited Review

Can Individualized Lumbar Pseudarthrosis Prevention Strategies be Cost-Effective?

Kamila J. Oster, BA

Orthopaedic Spine Institute

Hinsdale, IL

Vivek Mohan, MD, FAAOS

Orthopaedic Spine Institute

Hinsdale, IL

Introduction

Lumbar spine surgery is a common intervention for patients with disc herniations, spinal stenosis, spondylolisthesis, and traumatic spinal pathology.1 Among these procedures, lumbar fusion is frequently performed to stabilize the spine and decompress neural elements in order to relieve pain and improve function.1 Despite its widespread use, lumbar fusion carries a risk of long-term complications, most notably lumbar nonunion, or pseudarthrosis, in which the intended osseous fusion between vertebral segments fails to occur.2,3

Lumbar pseudarthrosis is associated with persistent pain, mechanical instability, neurological symptoms, and functional decline, often necessitating revision surgery.2 These revisions are technically demanding and resource-intensive and are associated with prolonged recovery and increased complication rates.3 Consequently, lumbar pseudarthrosis imposes a substantial economic burden on patients and healthcare systems alike.⁴ This article examines the financial impact of lumbar pseudarthrosis and explores whether investment in biologics, higher-cost implants, or surgical strategies aimed at preventing pseudarthrosis may represent a cost-effective approach in the long term.

Understanding Lumbar Pseudarthrosis

Lumbar pseudarthrosis occurs when adequate bony fusion fails to develop following spinal arthrodesis.2,5 Diagnosing lumbar pseudarthrosis requires a willingness to investigate persistent or new symptoms with a thorough postoperative assessment. Although no universally accepted diagnostic criteria exist, pseudarthrosis is most commonly identified using radiographic imaging, including dynamic plain radiographs and computed tomography. Diagnostic features of pseudarthrosis frequently cited in the literature include a lack of bridging bony trabeculation across the fusion segment, peri-implant radiolucency, and abnormal motion on dynamic flexion-extension radiographs.5

Despite not being an across-the-board directive, the US Food and Drug Administration’s (FDA) criteria are commonly cited thresholds used in assessments and trials. The (FDA) radiographic criteria for successful lumbar fusion is defined as less than 3 mm of translational motion and less than 5° of angular motion on flexion-extension radiographs.5 Additionally, delayed hardware failure, such as screw or rod fractures occurring more than 3 months postoperatively, is widely regarded as indicative of pseudarthrosis.

The etiology of lumbar pseudarthrosis is multifactorial and may include infection, suboptimal biological healing, inadequate mechanical stability, patient-related risk factors, or technical issues related to surgical approach or implant selection.3,6 Clinically, patients with pseudarthrosis may experience persistent axial pain, segmental instability, or reduced mobility and in some cases, progressive neurological symptoms.6 As pseudarthrosis undermines the primary goals of lumbar fusion, to relieve pain and restore function, affected patients frequently require additional intervention, including revision surgery, prolonged rehabilitation, and chronic pain management.2,7

The Cost of Lumbar Pseudarthrosis

The economic burden of lumbar pseudarthrosis arises from both direct and indirect costs. Direct costs include surgical revision, extended hospitalizations, postoperative rehabilitation and long-term pain management. Revision surgery is often necessary when pseudarthrosis is identified. These surgeries tend to be more complex than index surgeries, often requiring longer operative times, specialized instrumentation, and advanced surgical expertise.3,4 As a result, revision procedures carry higher complication rates and substantially increased costs. Reported estimates suggest that revision lumbar fusion may cost between $50,000 and $150,000, depending on procedural complexity and regional variation.3

Hospitalization costs further compound this burden. Patients undergoing revision surgery frequently experience longer inpatient stays, with a single prolonged hospitalization adding an estimated $10,000 to $50,000 or more to the total healthcare expenditures.4 Following discharge, many patients require extensive physical therapy, pharmacologic pain management, and in some cases, durable medical equipment, contributing several thousand additional dollars per patient.4

Indirect costs are also significant. Lumbar pseudarthrosis often results in prolonged work absence or permanent disability, leading to lost wages, reduced productivity, and increased reliance on social support systems.7 These losses are particularly pronounced among patients in physically demanding occupations. Furthermore, chronic pain and functional impairment can negatively affect quality of life and contribute to mental health disorders such as depression and anxiety, increasing long-term healthcare utilization.7

Collectively, when both direct and indirect costs are considered, the economic impact of lumbar pseudarthrosis is substantial. Estimates suggest that pseudarthrosis-related expenditures contribute billions of dollars annually to the healthcare costs in the United States alone.3,4

Is the use of expensive implants and biologics to prevent pseudarthrosis a long-term cost-effective approach?

Given the high financial and personal costs associated with lumbar pseudarthrosis, increasing attention has been directed toward preventative strategies, even when these involve higher upfront expenditures. Such strategies include the use of advanced biologics, custom or bioactive implants, and more extensive or combined surgical approaches designed to maximize fusion rates.6

Biologics

Traditional lumbar fusion techniques rely on metallic instrumentation combined with autograft or allograft bone. Commonly, lumbar fusions are performed using a mixture of allograft and local autograft. Multiple biological properties of allograft influence fusion rate. These include, osteoconductivity, osteoinductivity, osteogenicity, mechanical strength and vascularity.8,9 Iliac crest autograft has traditionally been the gold standard for grafting as it participates in all three processes of bone healing: osteoconduction, osteoinduction, and osteogenesis.10 However, due to the morbidity and pain stemming from iliac crest bone harvest, various allograft options have been developed for use in spinal fusions.11 Thus, allograft for fusions include structural and non-structural options. Cortical rings have been used extensively for interbody cages for decades. Non-structural grafts include demineralized bone matrix (DBM), cortical fibers, and cancellous chips or sponges. These bone grafts are often used as extenders in combination with the local autograft from the fusion level and used in posterior or posterolateral fusions as well as filler for the remaining interbody space. These forms of allograft do not contain live cells but provide the osteoconductive matrix for which new bone can form.

DBMs not only have osteoconductive properties but also have growth factors that participate in the osteoinductive process of new bone formation.12 Grafton gel was the first commercially available DBM in 1991 and since then many different vendors have developed their own proprietary version of DBMs.12 Variations in formulation and manufacturing processes have shown different outcomes among DBMs. Several important factors were noted: the higher amounts of BMP and the absence of carriers improved fusion rates.12 As recent as 2020, a meta-analysis by Han et al comparing DBM to autograft in lumbar fusion cases saw no significant difference in fusion rates in posterolateral fusion (risk ratio [RR], 1.03; 95% CI, 0.90–1.17; P = 0.66) and interbody fusion (RR, 1.13; 95% CI, 0.91–1.39; P = 0.27). DBMs remain as cost-effective as a bone graft option in lumbar fusion with comparable outcomes to iliac crest autograft, without the comorbidities of the harvest procedure.13

In cases where bone graft is unavailable or undesirable, osteoinductive biologics, particularly bone morphogenetic proteins (BMPs), have been introduced to enhance fusion by stimulating bone formation.14,15 Multiple studies have demonstrated that BMP use can significantly improve fusion rates, particularly in high-risk patients, thereby reducing the incidence of pseudarthrosis and the need for revision surgery.14,15,16 Although BMPs carry higher initial costs and specific risk profiles, improved fusion success may translate into long-term cost savings by avoiding revision procedures and associated indirect costs.17,18,19

Advanced and Custom Implants

Advances in implant technology have similarly aimed to improve fusion outcomes. Titanium interbody devices with nano-modulated or acid-etched bioactive surfaces have been shown to facilitate osseointegration using allograft and local autologous bone alone, potentially obviating the need for biologics.20 More recently, patient-specific 3D-printed titanium cages have demonstrated promising short-term clinical and radiographic outcomes. A prospective trial by Seex et al reported favorable fusion and functional results using patient-specific implants, suggesting potential long-term benefits as longer follow-up data become available.21

3D-printing technology has enabled a paradigm shift from standardized implants to anatomically precise, biomechanically optimized devices tailored to individual patients. Using advanced additive manufacturing techniques such as selective laser melting and electron beam melting, manufacturers can create titanium interbody cages with controlled porosity, lattice architectures, and surface roughness that closely mimic cancellous bone.22 This structural biomimicry enhances osteoconductive and osteoinductive potential while allowing customization of footprint, lordotic angle, and endplate conformity to match patient-specific anatomy.22,23 Such precision is particularly relevant in complex deformity correction, revision surgery, or cases with significant endplate compromise, where achieving optimal load distribution and primary stability is critical to successful arthrodesis.22

While these customized implants are more costly than standard cages, their ability to enhance fusion biology and biomechanics may reduce revision rates and associated expenditures over time.24,25 See Figure 1 below.

Figure 1. Custom 3D printed titanium ALIF implant along with MIS posterior instrumentation and fusion for degenerative spondylolisthesis in a very active 62yo male.

Surgical Approach and Fusion Strategy

Surgical approach also plays a critical role in fusion success. More extensive fusion constructs, such as transforaminal lumbar interbody fusion (TLIF) combined with posterior facet fusion, or circumferential approaches combining anterior lumbar interbody fusion techniques (including ALIF, OLIF, LLIF) with posterior instrumentation, may increase initial costs but offer improved mechanical stability and fusion potential.26,27

Figure 2. Adding facet fusion along with the MIS TLIF increases fusion mass area. The facet joint is the shortest distance between the vertebral levels, decreasing potential time to fusion.

Figure 3. MIS Bilateral TLIF performed in a 36 yo male with isthmic spondylolisthesis, to avoid the ALIF approach but provide ample surface area for interbody fusion.

Anterior lumbar fusion techniques include several newer exposures of the anterior spine, including oblique and lateral approaches, but still fall under the category of approaches anterior to the transverse processes. The result of placing a cage via an anterior approach, as opposed to the posterior or transforaminal approaches, allows for placement of larger interbody grafts and biologics, and thus provides a larger fusion surface area.28 A meta-analysis reported fusion rates of 88% for stand-alone ALIF and 94% when supplemental posterior fixation was used.29 Comparative studies have demonstrated similar long-term clinical outcomes between anterior and posterior approaches, although ALIF has been associated with shorter hospital stays and reduced intraoperative blood loss in some series.26,27 Often the limiting factor, the standard anterior approach may not be available at certain institutions lacking an exposure surgeon.

While fusion rates across ALIF, PLIF, TLIF, and posterolateral fusion are generally comparable, certain pathologies, such as L5–S1 isthmic spondylolisthesis, may be more amenable to anterior or combined approaches due to anatomical and biomechanical considerations.29 Ultimately, the choice of surgical strategy should be individualized, balancing patient-specific risk factors, alignment goals, and fusion potential to minimize the likelihood of pseudarthrosis and subsequent revision.

To date, no randomized controlled trial has directly compared fusion rates among different lumbar fusion techniques. However, valuable insight can be drawn from recent high-quality evidence in the cervical spine. The landmark FUSE randomized controlled trial evaluated 3-level anterior cervical discectomy and fusion (ACDF) versus combined anterior–posterior fusion. At 24 months, 67% of patients treated with anterior-only fusion demonstrated radiographic evidence of pseudarthrosis at one or more levels, with 23% requiring revision surgery. In contrast, patients treated with combined anterior–posterior fusion exhibited a markedly lower pseudarthrosis rate of 25%, and only 2% required revision surgery.30 These findings underscore several critical considerations: fusion failure may be substantially underrecognized, combined anterior–posterior constructs should be more strongly considered in multilevel or high-risk cases, and appropriate use of implants and biologics is often necessary to achieve durable arthrodesis (Figure 4).

Figure 4. C4-C7 anterior and posterior cervical fusion in a 55 yo smoker, 9 month postop

While analogous randomized data are lacking in the lumbar spine, similar principles likely apply. In complex lumbar pathology, multilevel disease, or biologically compromised patients, more robust fusion strategies, such as TLIF with supplemental posterior fusion or circumferential constructs combining ALIF with posterior instrumentation, may provide enhanced biomechanical stability and a larger fusion surface area to increase the fusion rate. While these approaches increase operative complexity and initial cost, they may reduce the likelihood of pseudarthrosis and the need for costly revision surgery.

Cost-Effectiveness Analysis

Revision lumbar fusion for symptomatic nonunion represents a substantial economic burden. A 2-year cost analysis of patients undergoing revision lumbar fusion demonstrated mean direct health care expenditures of US$32,915 ± $8,344, with a wide variability influenced by medical comorbidities, complications, and the need for further interventions, based on cost data published in 2018.4 Given that revision procedures account for a disproportionately high share of resource utilization, even modest reductions in pseudarthrosis rates yield meaningful downstream savings when these costs are modeled within a decision-analytic framework.

Several economic evaluations have assessed the value of biological augmentation and advanced implant technology in mitigating pseudarthrosis risk. One study reported that recombinant bone morphogenetic protein (BMP-2) reduced nonunion rates by roughly 40%, ultimately generating net cost savings when the high cost of revision operations, readmissions, and indirect societal burdens were included.15 However, in a 2021 study by McGrath et al, approximate costs to the hospital for the product per-dose expense were up to US $5,569, with subsequent charges to the insurer up to $25,617.31 A large retrospective analysis of commercial insurance claims found a reduced repeat-fusion rate when BMP was used—2.3% vs 3.4% at 1 year, corresponding to an odds ratio of ~0.66.16. Although the upfront procedural cost is higher, the long-term return on investment (ROI) becomes favorable in contexts where pseudarthrosis risk is meaningfully reduced: ie, multilevel fusions, smokers, diabetics, and patients with osteoporosis or over 60 years old.18

Implant innovations offer an alternative mechanism for improving fusion rates while minimizing reliance on high-cost biologics. A study of lateral lumbar interbody fusions (LLIFs) using 3D‑printed porous titanium interbody implants packed only with inexpensive ceramic bone graft substitute (β‑tricalcium phosphate/hydroxyapatite) achieved ~99% fusion rates.25 Likewise, titanium interbody devices engineered with nanosurface-modulated or acid-etched bioactive surfaces have demonstrated robust fusion performance using only allograft chips and local autologous bone/blood, suggesting implicit cost savings when biologics are omitted.20

Based on these meta-analyses, it is clear that in higher risk patients, reducing the rate of revisions is the key, as cost savings are achieved at a much lower threshold. In low to moderate risk patients, ie, a 1-level lumbar fusion in a healthy 45-year-old male, adding costly bone grafts, such as rBMP-2, along with additional hardware on all these patients, may not produce a significant reduction in cost savings at scale, with the intent to avoid pseudarthrosis formation. Therefore, it is critical to evaluate each patient’s risk factors in detail before proceeding and knowing how to categorize their individual risk for pseudarthrosis. As the cost data listed here are likely already outdated, we can only assume that the costs are much higher today for both primary and revision surgery. Data from 2022 showed the average cost of 2-year total health care spending due to a lumbar pseudarthrosis to be $78,928, clearly indicating the burden of lumbar pseudarthrosis.33

Reducing revision procedures also alleviates systemic strain—lower utilization of operating room time, fewer hospital admissions, and diminished cumulative risk exposure for patients. Emerging technologies such as facet-fusion implants for TLIF procedures may further enhance fusion rates, though comparative cost-effectiveness data remain limited. Similarly, for combined ALIF and PLIF approaches, existing literature that compares 360° fusions with posterolateral-only constructs suggests potential clinical benefit, but economic outcomes require more rigorous study.26

Conclusion

From an economic perspective, the burden of lumbar pseudarthrosis is substantial and extends beyond direct surgical costs. With ongoing inflation and rising healthcare expenditures, the true cost of revision surgery likely exceeds historical estimates and will easily surpass $50,000 per case. As medical costs continue to rise, the financial penalty associated with fusion failure becomes increasingly difficult to justify. In high-risk populations, including patients with obesity, diabetes, frailty, osteoporosis and smokers, it may be prudent to delay elective surgery when feasible to optimize all modifiable risk factors, while concurrently developing an unique individualized surgical strategy that can reduce their risk of pseudarthroses.

Importantly, the costs presented here do not thoroughly account for indirect economic consequences, such as lost productivity, time away from work, caregiver burden, or prolonged postoperative rehabilitation. Inclusion of these factors would further lower the threshold at which preventative strategies become cost-effective and further strengthen the economic argument for pseudarthrosis prevention.

In summary, lumbar pseudarthrosis imposes a significant clinical and financial burden on patients and healthcare systems. While advanced implants, biologics, and combined surgical approaches entail higher upfront costs, their potential to reduce revision rates, shorten recovery, and improve long-term outcomes suggests that prevention may ultimately represent the more economical strategy. A patient-specific, risk-stratified approach—balancing surgical complexity, biological and structural augmentation, and anticipated downstream costs—appears essential to optimizing both clinical outcomes and health care resource utilization in lumbar spine fusions.

References

Author Disclosures

K Oster: Nothing to disclose

V Mohan: Consulting: Carelon (B), Innosys (Future Compensation Expected), Sanara Medical Technologies (B); Speaking and/or Teaching Arrangements: Baxter (B, Outside 24-Month Requirement).