Bone union after spinal fusion surgery using local bone in long-term bisphosphonate users: a prospective comparative study

Surgical outcomes of anterior column reconstruction for spinal fractures caused by minor trauma-preoperative examination of the number of intervertebral bone bridges is key to obtaining good bone fusion

BACKGROUND

To achieve good bone fusion in anterior column reconstruction for vertebral fractures, not only bone mineral density (BMD) and bone metabolism markers but also lever arms due to bone bridging between vertebral bodies should be evaluated. However, until now, no lever arm index has been devised. Therefore, we believe that the maximum number of vertebral bodies that are bony and cross-linked with the contiguous adjacent vertebrae (maxVB) can be used as a measure for lever arms. The purpose of this study is to investigate the surgical outcomes of anterior column reconstruction for spinal fractures and to determine the effect of bone bridging between vertebral bodies on the rate of bone fusion using the maxVB as an indicator of the length of the lever arm.

METHODS

The clinical data of 81 patients who underwent anterior column reconstruction for spinal fracture between 2014 and 2022 were evaluated. The bone fusion rate, back pain score, between the maxVB = 0 and the maxVB ≥ 2 patients were adjusted for confounding factors (age, smoking history, diabetes mellitus history, BMD, osteoporosis drugs, surgical technique, number of fixed vertebrae, materials used for the anterior props, etc.) and analysed with multivariate or multiple regression analyses. The bone healing rate and incidence of postoperative back pain were compared among the three groups (maxVB = 0, 2≦maxVB≦8, maxVB ≧ 9) and divided by the maxVB after adjusting for confounding factors.

RESULTS

Patients with a maxVB ≥ 2 had a significantly higher bone fusion rate (p < 0.01) and postoperative back pain score (p < 0.01) than those with a maxVB = 0. Among the three groups, the bone fusion rate and back pain score were significantly higher in the 2≦maxVB≦8 group (p = 0.01, p < 0.01).

CONCLUSIONS

Examination of the maxVB as an indicator of the use of a lever arm is beneficial for anterior column reconstruction for vertebral fractures. Patients with no intervertebral bone bridging or a high number of bone bridges are in more need of measures to promote bone fusion than patients with a moderate number of bone bridges are.

Efficacy and safety of different anti-osteoporotic drugs for the spinal fusion surgery: A network meta-analysis

BACKGROUND

Administering anti-osteoporotic agents to patients perioperatively is a widely accepted approach for improving bone fusion rates and reducing the risk of complications. The best anti-osteoporotic agents for spinal fusion surgery remain unclear.

AIM

To investigate the efficacy and safety of different anti-osteoporotic agents in spinal fusion surgery via network meta-analysis.

METHODS

Searches were conducted in four electronic databases (PubMed, EMBASE, Web of Science, the Cochrane Library and China National Knowledge Infrastructure (CNKI) from inception to November 2022. Any studies that compared anti-osteoporotic agents vs placebo for spinal fusion surgery were included in this network meta-analysis. Outcomes included fusion rate, Oswestry disability index (ODI), and adverse events. Network meta-analysis was performed by R software with the gemtc package.

RESULTS

In total, 13 randomized controlled trials were included in this network meta-analysis. Only teriparatide (OR 3.2, 95%CI: 1.4 to 7.8) was more effective than placebo in increasing the fusion rate. The surface under the cumulative ranking curve (SUCRA) of teriparatide combined with denosumab was the highest (SUCRA, 90.9%), followed by teriparatide (SUCRA, 74.0%), zoledronic acid (SUCRA, 43.7%), alendronate (SUCRA, 41.1%) and risedronate (SUCRA, 35.0%). Teriparatide (MD -15, 95%CI: -28 to -2.7) and teriparatide combined with denosumab (MD -20, 95%CI: -40 to -0.43) were more effective than placebo in decreasing the ODI. The SUCRA of teriparatide combined with denosumab was highest (SUCRA, 90.8%), followed by teriparatide (SUCRA, 74.5%), alendronate (SURCA, 52.7), risedronate (SURCA, 52.1%), zoledronic acid (SURCA, 24.2%) and placebo (SURCA, 5.6%) for ODI. The adverse events were not different between groups.

CONCLUSION

This network meta-analysis suggests that teriparatide combined with denosumab and teriparatide alone significantly increase the fusion rate and decrease the ODI without increasing adverse events. Based on current evidence, teriparatide combined with denosumab or teriparatide alone is recommended to increase the fusion rate and to reduce ODI in spinal fusion patients.

Number of contiguous vertebral cross-links in the spine indicates bone formation: a cross-sectional study

BACKGROUND

As an indicator to evaluate the risk of fracture in diffuse idiopathic skeletal hyperostosis, the maximum number of vertebral bodies' bone cross-linked with contiguous adjacent vertebrae (max VB) was developed. This study retrospectively investigates the relationship between max VB, bone mineral density (BMD), and bone metabolic markers (BMM).

METHODS

In this cross-sectional study (from April 2010 to January 2022), males (n = 114) with various max VB from the thoracic vertebra to the sacrum, measured using computed tomography scans, were selected to assess femur BMD and BMM. The association of max VB with the total type I procollagen N-terminal propeptide (P1NP), tartrate-resistant acid phosphatase 5b (TRACP-5b), and bone turnover ratio (BTR = TRACP-5b/P1NP) as well as its relationship with femur BMD with P1NP and TRACP-5b, were investigated. Furthermore, the relationship between P1NP and TRACP-5b was investigated.

RESULTS

P1NP increased in proportion to max VB and TRACP-5b increased in proportion to P1NP. Moreover, BTR was inversely proportional to max VB. Finally, femur BMD was inversely proportional to P1NP and TRACP-5b.

CONCLUSION

As max VB increased with P1NP-a potential osteogenesis indicator-and BTR was inversely proportional to max VB with compensatory TRACP-5b increase, max VB can be considered as a possible predictor of bone fusion.

Multi-modulation of immune-inflammatory response using bioactive molecule-integrated PLGA composite for spinal fusion

Despite current developments in bone substitute technology for spinal fusion, there is a lack of adequate materials for bone regeneration in clinical applications. Recombinant human bone morphogenetic protein-2 (rhBMP-2) is commercially available, but a severe inflammatory response is a known side effect. Bone graft substitutes that enhance osteogenesis without adverse effects are needed. We developed a bioactive molecule-laden PLGA composite with multi-modulation for bone fusion. This bioresorbable composite scaffold was considered for bone tissue engineering. Among the main components, magnesium hydroxide (MH) aids in reduction of acute inflammation affecting disruption of new bone formation. Decellularized bone extracellular matrix (bECM) and demineralized bone matrix (DBM) composites were used for osteoconductive and osteoinductive activities. A bioactive molecule, polydeoxyribonucleotide (PDRN, PN), derived from trout was used for angiogenesis during bone regeneration. A nano-emulsion method that included Span 80 was used to fabricate bioactive PLGA-MH-bECM/DBM-PDRN (PME2/PN) composite to obtain a highly effective and safe scaffold. The synergistic effect provided by PME2/PN improved not only osteogenic and angiogenic gene expression for bone fusion but also improved immunosuppression and polarization of macrophages that were important for bone tissue repair, using a rat model of posterolateral spinal fusion (PLF). It thus had sufficient biocompatibility and bioactivity for spinal fusion.

Effect of Teriparatide Versus Zoledronate on Posterior Lumbar Interbody Fusion in Postmenopausal Women with Osteoporosis

OBJECTIVE

We evaluated the efficacy of teriparatide versus zoledronate on spinal fusion in osteoporotic patients after posterior lumbar interbody fusion (PLIF).

METHODS

Postmenopausal women with osteoporosis undergoing PLIF for degenerative spondylolisthesis were randomly assigned to receive either zoledronate or teriparatide. During the 2-year follow-up period, serial radiographs were used to determine fusion status and instrumentation-related sequelae (a composite of adjacent vertebral compressive fracture, instrumentation failure, and fusion failure). The bone mineral density (BMD) and Oswestry disability index (ODI) were also serially measured.

RESULTS

Of the 77 patients, 36 were in the teriparatide group and 41 in the zoledronate group and had completed the 2-year follow-up assessments. Bony union had been achieved more frequently in the teriparatide group than in the zoledronate group at 6 months postoperatively (P < 0.05), although the overall rate of bone union was comparable between the 2 groups. The incidence of instrumentation-related sequelae was also comparable between the 2 groups (teriparatide vs. zoledronate group, 13.9% vs. 22.0%). Regarding antiosteoporosis, the BMD values had significantly improved in both groups at the last follow-up. The teriparatide group had attained more BMD increments at 12 months postoperatively than had the zoledronate group. Furthermore, the ODI had consistently decreased in both groups with a lower ODI in the teriparatide group than in the zoledronate group at 12 months postoperatively.

CONCLUSIONS

Among postmenopausal women with osteoporosis, teriparatide showed superior bone union at 6 months and greater BMD improvement at 12 months after PLIF compared with zoledronate administration, although both resulted in similar overall effects on spinal fusion.

Best Practice Guidelines for Assessment and Management of Osteoporosis in Adult Patients Undergoing Elective Spinal Reconstruction

STUDY DESIGN

Expert consensus study.

OBJECTIVE

This expert panel was created to establish best practice guidelines to identify and treat patients with poor bone health prior to elective spinal reconstruction.

SUMMARY OF BACKGROUND DATA

Currently, no guidelines exist for the management of osteoporosis and osteopenia in patients undergoing spinal reconstructive surgery. Untreated osteoporosis in spine reconstruction surgery is associated with higher complications and worse outcomes.

METHODS

A multidisciplinary panel with 18 experts was assembled including orthopedic and neurological surgeons, endocrinologists, and rheumatologists. Surveys and discussions regarding the current literature were held according to Delphi method until a final set of guidelines was created with over 70% consensus.

RESULTS

Panelists agreed that bone health should be considered in every patient prior to elective spinal reconstruction. All patients above 65 and those under 65 with particular risk factors (chronic glucocorticoid use, high fracture risk or previous fracture, limited mobility, and eight other key factors) should have a formal bone health evaluation prior to undergoing surgery. DXA scans of the hip are preferable due to their wide availability. Opportunistic CT Hounsfield Units of the vertebrae can be useful in identifying poor bone health. In the absence of contraindications, anabolic agents are considered first line therapy due to their bone building properties as compared with antiresorptive medications. Medications should be administered preoperatively for at least 2 months and postoperatively for minimum 8 months.

CONCLUSION

Based on the consensus of a multidisciplinary panel of experts, we propose best practice guidelines for assessment and treatment of poor bone health prior to elective spinal reconstructive surgery. Patients above age 65 and those with particular risk factors under 65 should undergo formal bone health evaluation. We also established guidelines on perioperative optimization, utility of various diagnostic modalities, and the optimal medical management of bone health in this population.Level of Evidence: 5.

Therapeutics for enhancement of spinal fusion: A mini review

Objective

With the advances in biological technologies over the past 20 years, a number of new therapies to promote bone healing have been introduced. Particularly in the spinal surgery field, more unprecedented biological therapeutics become available to enhance spinal fusion success rate along with advanced instrumentation approaches. Yet surgeons may not have been well informed about their safety and efficacy profiles in order to improve clinical practices. Therefore there is a need to summarize the evidence and bring the latest progress to surgeons for better clinical services for patients.

Methods

We comprehensively reviewed the literatures in regard to the biological therapeutics for enhancement of spinal fusion published in the last two decades.

Results

Autograft bone is still the gold standard for bone grafting in spinal fusion surgery due to its good osteoconductive, osteoinductive, and osteogenic abilities. Accumulating evidence suggests that adding rhBMPs in combination with autograft effectively promotes the fusion rate and improves surgical outcomes. However, the stimulating effect on spinal fusion of other growth factors, including PDGF, VEGF, TGF-beta, and FGF, is not convincing, while Nell-1 and activin A exhibited preliminary efficacy. In terms of systemic therapeutic approaches, the osteoporosis drug Teriparatide has played a positive role in promoting bone healing after spinal surgery, while new medications such as denosumab and sclerostin antibodies still need further validation. Currently, other treatment, such as controlled-release formulations and carriers, are being studied for better releasing profile and the administration convenience of the active ingredients.

Conclusion

As the world's population continues to grow older, the number of spinal fusion cases grows substantially due to increased surgical needs for spinal degenerative disease (SDD). Critical advancements in biological therapeutics that promote spinal fusion have brought better clinical outcomes to patients lately. With the accumulation of higher-level evidence, the safety and efficacy of present and emerging products are becoming more evident. These emerging therapeutics will shift the landscape of perioperative therapy for the enhancement of spinal fusion.

Congress of Neurological Surgeons Systematic Review and Evidence-Based Guidelines for Perioperative Spine: Preoperative Osteoporosis Assessment

BACKGROUND

Osteoporosis is a metabolic bone disease that commonly affects the elderly. Degenerative spinal disease that may require surgical intervention is also prevalent in this susceptible population. If undiagnosed or untreated before spine surgery, osteoporosis may result in an increased risk of postoperative adverse events. Nontreatment of osteoporosis preoperatively may be related to a poor understanding of bone physiology, a lack of standardized treatment algorithms, limited cost-effective interventions, and reluctance by spine surgeons to be the primary provider of osteoporosis management.

OBJECTIVE

The objective of this evidence-based review is to develop guidelines for the preoperative assessment and treatment of osteoporosis in patients undergoing spine surgery.

METHODS

A systematic review of the literature was performed using the National Library of Medicine/PubMed database and Embase for studies relevant to preoperative diagnostic studies that predict increased risk of osteoporosis-related postoperative adverse events and whether the preoperative treatment of low bone mineral density (BMD) in patients with osteoporosis improves outcome.

RESULTS

Out of 281 studies, 17 met the inclusion criteria and were included for systematic review. The task force affirmed a Grade B recommendation that preoperative osteoporosis testing with a dual-energy X-ray absorptiometry scan (T-score < -2.5), a computed tomography scan (Hounsfield units <97.9), and serum vitamin D3 level (<20 ng/mL) predict an increased risk of osteoporosis-related adverse events after spine surgery. The task force determined a Grade B recommendation that preoperative osteoporosis treatment with teriparatide increases BMD, induces earlier and more robust fusion, and may improve select patient outcomes. There is insufficient evidence regarding preoperative treatment with bisphosphonates alone and postoperative outcome.

CONCLUSION

This evidence-based clinical guideline provides a recommendation that patients with suspected osteoporosis undergo preoperative assessment and be appropriately counseled about the risk of postoperative adverse events if osteoporosis is confirmed. In addition, preoperative optimization of BMD with select treatments improves certain patient outcomes.The full guidelines can be accessed at https://www.cns.org/guidelines/browse-guidelines-detail/3-preoperative-osteoporosis-assessment.

Long-Term Outcome After Midline Lumbar Fusion for the Treatment of Lumbar Spine Instability Due to Degenerative Disease

BACKGROUND

Midline lumbar fusion (MIDLF) is one promising new surgical technique that has been developed to minimize perioperative damage to the paravertebral stabilizing musculotendinous system. The aim of this study was to assess long-term clinical and radiological effects of MIDLF.

METHODS

This prospective cohort study evaluated patients who underwent MIDLF for degenerative spinal instability. Clinical and radiological examinations were performed before and after surgery. Perioperative and postoperative complications were recorded. Follow-up was 2 years. P ≤ 0.05 was considered statistically significant.

RESULTS

The study included 64 patients (mean age 58.9 ± 10.7 years; 41 women [64.1%]). The most frequent indication for MIDLF was degenerative spondylolisthesis grade I (28 cases [43.8%]); the prevalent spinal segment to be fused was L4-L5 (35 cases [54.7%]). Mean duration of surgery was 148.2 ± 28.9 minutes. Relief of low back pain and leg pain was significant and stable in the postoperative period as assessed by visual analog scale (P < 0.001). Of patients, 86.9% reported fair, good, or excellent outcomes in terms of pain relief based on MacNab score 2 years after surgery. Patients' level of function in activities of daily living improved significantly based on Oswestry Disability Index score: from 66.8 ± 9.8 before surgery to 33.9 ± 16.5 2 years after surgery (P < 0.001). X-rays and computed tomography at 12 months showed interbody fusion in 46 cases (73.4%), inconclusive results in 13 cases (20.3%), and no fusion in 4 cases (6.3%). No damage to neural or vascular structures and no failure of hardware or screw loosening were recorded.

CONCLUSIONS

MIDLF is a safe, efficient method for surgical treatment of lumbar spine instability. Its limited invasiveness contributes to better preservation of paravertebral muscles and enhanced postoperative spinal stability.

Negative pharmacological effect on spine fusion: A narrative review of the literature of evidence-based treatment

Spine fusion surgery is commonly performed for diverse indications, the most frequent one being degenerative spine diseases. Despite the growing importance of this surgery, there is limited evidence concerning the effects of drugs on the process of spine fusion and healing. While asymptomatic sometimes, nonunion of the spine can have tremendous repercussions on the patients' quality of life and the healthcare system rendering it an "expensive complication". This literature review identifies the role of some perioperative drugs in spine fusion and reveals their potential role in pseudarthrosis of the spine. This review also benefits spine surgeons looking for current evidence-based practices. We reviewed the data related to nonsteroidal anti-inflammatory drugs (NSAIDs), corticosteroids, vancomycin, bisphosphonates, proton pump inhibitors (PPIs), pregabalin, and opioids. From the available experimental and clinical studies, we conclude that bisphosphonates might positively influence the process of spine fusion, while steroids and vancomycin have shown variable effects, and the remaining medications likely disturb healing and union of the spine. We recommend spine surgeons be cautious about the drugs they resort to in the critical perioperative period until further clinical studies prove which drugs are safe to be used.

Antiresorptive and anabolic medications used in the perioperative period of patients with osteoporosis undergoing spine surgery: their impact on the biology of fusion and systematic review of the literature

OBJECTIVE

Osteoporosis represents the most common metabolic disease of the bone, with an estimated 10% of adults aged 50 years or older affected in the United States. This patient population is at increased risk for spine fracture and instrumentation-related complications after spine surgery. Surgeon knowledge of the available treatments for patients with low bone mineral density (BMD) and how they impact biology of fusion may help mitigate negative effects in the postoperative period. Recombinant parathyroid hormone, which is sold under the name teriparatide, is the most extensively studied bone-protecting agent in humans. Additionally, the success of the monoclonal antibody denosumab has led to further clinical investigations of human patients undergoing spine surgery. Another monoclonal antibody, romosozumab, was recently approved by the US FDA for human use in patients with osteoporosis. Although studies of romosozumab in patients undergoing spine surgery have not been conducted, this is a promising potential therapeutic agent based on its early success in preclinical and clinical trials. Here, the authors aimed to review the mechanisms of action and evidence of use of antiresorptive and anabolic agents in patients with osteoporosis undergoing spine surgery.

METHODS

In accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, a systematic review was conducted to explore the antiresorptive and anabolic agents used in the perioperative period in patients with osteoporosis undergoing spinal surgery. The search was performed by using the PubMed, Embase, and Cochrane Library databases. Titles and abstracts were screened and subsequently selected for full review.

RESULTS

The initial search returned 330 articles. Of these articles, 23 final articles were included and reviewed. Many of these articles reported that use of adjuvant agents in the perioperative period improved radiographic evidence of bony fusion and bone fusion rates. These agents tended to improve BMD postoperatively.

CONCLUSIONS

Although antiosteoporosis agents are effective to varying degrees as treatments of patients with low BMD, teriparatide and bisphosphonates have been the most extensively studied with respect to spinal instrumentation. The advent of newer agents represents an area for further exploration, especially due to the current paucity of controlled investigations. It is imperative for spine surgeons to understand the mechanisms of action of these drugs and their effects on biology of fusion.

Osteoporosis treatment in patients undergoing spinal fusion: a systematic review and meta-analysis

OBJECTIVE

Bisphosphonates and teriparatide are the most common therapies used in the treatment of osteoporosis. Their impact on fusion rates in osteoporotic patients following spinal fusion has yet to be concretely defined, with previous systematic reviews focusing heavily on bisphosphonates and lacking clinical insight on the utility of teriparatide. Herein the authors present an updated meta-analysis of the utility of both bisphosphonates and teriparatide in improving spinal fusion outcomes in osteoporotic patients.

METHODS

After a comprehensive search of the English-language literature in the PubMed and Embase databases, 11 clinical studies were included in the final qualitative and quantitative analyses. Of these studies, 9 investigated bisphosphonates, 7 investigated teriparatide, and 1 investigated a combination of teriparatide and denosumab. Odds ratios and 95% confidence intervals were calculated where appropriate.

RESULTS

A meta-analysis of the postoperative use of bisphosphonate demonstrated better odds of successful fusion as compared to that in controls during short-term monitoring (OR 3.33, 95% CI 1.72-6.42, p = 0.0003) but not long-term monitoring (p > 0.05). Bisphosphonate use was also shown to significantly reduce the likelihood of postoperative vertebral compression fracture (VCF; OR 0.07, 95% CI 0.01-0.59, p = 0.01) and significantly reduce Oswestry Disability Index scores (mean difference [MD] = -2.19, 95% CI -2.94 to -1.44, p < 0.00001) and visual analog scale pain scores (MD = -0.58, 95% CI -0.79 to -0.38, p < 0.00001). Teriparatide was found to significantly increase fusion rates at long-term postoperative periods as compared to rates after bisphosphonate therapy, with patients who received postoperative teriparatide therapy 2.05 times more likely to experience successful fusion (OR 2.05, 95% CI 1.17-3.59, p = 0.01).

CONCLUSIONS

The authors demonstrate the benefits of bisphosphonate and teriparatide therapy independently in accelerating fusion during the first 6 months after spinal fusion surgery in osteoporotic patients. In addition, they show that teriparatide may have superior benefits in spinal fusion during long-term monitoring as compared to those with bisphosphonates. Bisphosphonates may be better suited in preventing VCFs postoperatively in addition to minimizing postoperative disability and pain.

Postoperative bisphosphonate do not significantly alter the fusion rate after lumbar spinal fusion: a meta-analysis

Background

To evaluate the effect of postoperative BP treatment on improving the fusion rate after lumbar spinal fusion surgery by performing a meta-analysis of randomized controlled trials (RCTs) and other comparative cohort studies.

Methods

A comprehensive search of PubMed, EMBASE, the Web of Science, and the Cochrane Central Register of Controlled Trials was performed for RCTs and other comparative cohort studies on the effect of BP treatment on improving the fusion rate after lumbar spinal fusion surgery. The primary outcome measures were the number of patients with bone formation grades A, B, and C at 12 months of follow-up; fusion rates at 12 and 24 months of follow-up; vertebral compression fracture (VCF) at 12 and 24 months of follow-up; pedicle screw loosening at 24 months of follow-up; and cage subsidence, the Oswestry disability index (ODI), and the visual analogue score (VAS) at 12 months of follow-up. The final search was performed in July 2020.

Results

Seven studies with 401 patients were included. Compared with the placebo, BP treatment did not significantly alter the number of patients with bone formation grades A, B, and C, or the VAS at the 12-month follow-up or the fusion rates at the 12- and 24-month follow-ups. In addition, compared with the placebo, BPs significantly reduced the risks of VCF at the 12- and 24-month follow-ups, pedicle screw loosening at the 24-month follow-up, and cage subsidence and the ODI at the 12-month follow-up.

Conclusions

Postoperative BPs do not clearly improve bone formation and the fusion rate, but they reduce VCF, cage subsidence, and loosening of pedicle screws after lumbar fusion surgery compared with the control treatment.

Osteoporosis increases the likelihood of revision surgery following a long spinal fusion for adult spinal deformity

BACKGROUND

Adult spinal deformity (ASD) can be a debilitating condition that requires surgical intervention. ASD patients often present with osteoporosis, predisposing them to increased rates of instrumentation failure and postoperative fractures, frequent reasons for revision surgery. We hypothesized that the rate and timing of revision surgery are different in osteoporotic and nonosteoporotic patients undergoing long fusions for ASD. To our knowledge, the timing of revision surgeries, in particular, have not previously been explored.

PURPOSE

To determine the rate and timing of revision surgery in osteoporotic and nonosteoporotic patients following a long fusion for ASD.

STUDY DESIGN

Retrospective comparative study.

PATIENT SAMPLE

ASD patients who underwent a long spinal fusion surgery at two large academic medical centers from 2010 to 2019.

OUTCOME MEASURES

Occurrence of revision surgery.

METHODS

Inclusion criteria were patient age of least 40 years and spinal fusion spanning at least seven levels for ASD. Patient records were reviewed for a diagnosis of osteoporosis as per ICD codes and revision surgery within 2 years of the index procedure. Revision surgery was defined as an unplanned procedure related to the index surgery for the treatment of a spine-related complication. Chi-squared tests comparing demographic data, revision rates, and multiple revisions were conducted. The incidence and prevalence of revision surgeries as a function of time and osteoporotic status were evaluated for significant differences via the Mann-Whitney U and Mantel-Haenszel log rank tests. Finally, a logistic regression analysis was utilized to determine the predictive value of osteoporosis, age, and gender on the likelihood for complications.

RESULTS

Three hundred ninety-nine patients matched the study criteria. In the osteoporotic group, 40.5% of patients underwent a revision surgery compared to 28.0% in the nonosteoporotic group (p=.01). The occurrence of multiple revision surgeries following the index procedure was similar in both groups: 8.4% in osteoporotic patients and 8.6% in nonosteoporotic patients. Age and gender were not statistically correlated with the incidence of revision surgery.

CONCLUSIONS

ASD patients with osteoporosis have an increased risk of undergoing revision for a surgery-related complication within 2 years of the index procedure. These complications included failure of hardware, pseudoarthrosis, proximal junction failure, and infection, among other issues that required surgical intervention. As others have also highlighted the importance of poor bone density on construct failure, our data further underscore the importance of preoperative osteoporosis surveillance. Though intuitive, further study is needed to demonstrate that improving patients' bone density can decrease the incidence of related complications and the need or revision surgery.

Pharmacologic considerations in patients with osteoporosis undergoing lumbar interbody fusion: A systematic review

OBJECTIVE

As the ageing population continues to grow, the incidence of osteoporosis continues to rise. Patients with osteoporosis are often managed pharmacologically. It is unclear the impact of these medications on osteoporotic patients requiring lumbar interbody fusion, and whether differences exist with respect to patient outcomes among the different medication classes that are often employed. In this systematic review, the authors examine studies evaluating the impact of pharmacologic therapy on osteoporotic patients undergoing lumbar interbody fusion.

METHODS

Using PubMed and MEDLINE databases, the authors conducted a systematic literature review for studies published between 1986 and 2020 following PRISMA guidelines.

RESULTS

A total of 12 articles were ultimately selected. Studies assessing bisphosphonate usage, parathyroid hormone analogues, vitamin D, or combination therapies and their impact on lumbar interbody fusion were included.

CONCLUSIONS

The evidence regarding bisphosphonate therapy and improved fusion rates with reduced incidence of complications is inconsistent. While some studies suggest bisphosphonates to confer added benefit, other studies suggest no such improvements despite reduction in bone turnover biomarkers. Teriparatide, on the other hand, consistently demonstrated improved fusion rates and may reduce screw loosening events. In comparison studies against bisphosphonates, teriparatide demonstrates greater potential. A single study reported vitamin D3 to increase fusion rates, although more studies are needed to validate this finding. It is important to note that these benefits are only demonstrated in single-level fusion, with multi-level fusions not being significantly enhanced by teriparatide therapy. Combination therapy with denosumab further augment fusion rates. Further prospective randomized controlled trials are necessary before standardized recommendations regarding pharmacological intervention in patients undergoing LIF can be made.