Influence of alendronate and endplate degeneration to single level posterior lumbar spinal interbody fusion

Anti-osteoporosis medication in patients with posterior spine fusion: a systematic review and meta-analysis

BACKGROUND CONTEXT

Osteoporosis and osteopenia are common among patients undergoing posterior spine fusion surgery, presenting challenges such as pseudarthrosis, screw loosening, and poor patient outcomes. While pharmacological interventions are available, no consensus exists regarding the optimal perioperative treatment for these patients. Furthermore, the effectiveness of various treatment options in improving fusion rates and minimizing complications remains uncertain.

PURPOSE

To compare the effects of teriparatide, bisphosphonates, denosumab, and romosozumab in patients with posterior spine fusion with low bone mineral density (BMD).

STUDY DESIGN

Systematic review and meta-analysis PATIENT SAMPLE: Adult patients with low BMD receiving osteoporosis medications and undergoing posterior spine fusion surgery OUTCOME MEASURES: Fusion rate, subsequent vertebral fracture (VF), screw loosening, cage subsidence, proximal junctional kyphosis(PJK), and patient-reported outcomes (PROs), particularly the Visual Analogue Scale (VAS) and Oswestry Disability Index (ODI).

METHODS

A systematic search was conducted using PubMed, EMBASE, and Cochrane Library. Two reviewers independently selected and assessed relevant studies. Four groups were analyzed to evaluate the comparative effectiveness of antiosteoporosis medication on the outcome measures: Bisphosphonate versus Control; Teriparatide versus Control; Teriparatide versus Bisphosphonate; and Denosumab versus Control.

RESULTS

Bisphosphonate showed reduced subsequent VFs (odds ratio [OR]=0.27, 95% confidence interval [CI]=0.09-0.81) and cage subsidence (OR=0.29, 95% CI=0.11-0.75) and improved ODI scores at 12 months (standardized mean difference [SMD] [95% CI]=-0.75 [-1.42, -0.08]) compared to the control. Teriparatide showed a higher fusion rate (OR=3.52, 95% CI=1.84-6.75), lower screw loosening (OR=0.23, 95% CI=0.09-0.60), and improved ODI scores at 24 months (SMD [95% CI]=-0.57 [-0.99, -0.15]) compared to the control. Moreover, teriparatide showed a higher fusion rate (OR=2.28, 95% CI=1.67-3.11), lower subsequent VF (OR=0.22, 95% CI=0.09-0.51), and improved VAS score for back pain (VASB) (mean difference [MD] [95% CI]=-0.30 [-0.54, -0.07]) and ODI (SMD [95% CI]=-0.38[-0.64, -0.12]) scores at 12 months compared to bisphosphonate. Denosumab showed no significant difference in fusion rate or other complications compared to control.

CONCLUSION

Our results indicated that teriparatide should be used as the first-line perioperative treatment for patients with poor bone quality scheduled for posterior spine fusion. Teriparatide exhibited better fusion rates and reduced complications than controls and bisphosphonates, resulting in improved PROs. Moreover, bisphosphonates can be utilized in patients with contraindications to teriparatide since the former prevents osteoporosis-related complications compared to controls, resulting in improved PROs. Further studies are warranted to evaluate the potential effects of denosumab and romosozumab.

Personalized Approaches to Spine Surgery

Patient-centric decision-making has imbued all aspects of health care, including spine surgery. This review describes how spine surgeons can use evolving technologies and knowledge of disease and pain states to tailor their surgical approach to the individual patient. This includes preoperative screening for and optimization of low bone mineral density, intraoperative selection of implant material and customization of interbody cages and screws, and postoperative personalization of pain regimens and rehabilitation courses. By working in a multidisciplinary fashion, spine surgeons can avail themselves of these advances to provide individualized care.

Assessment of factors implicated in bone fusion after percutaneous endoscopic lumbar intervertebral fusion

Objective

Lumbar spinal fusion is a common procedure for treating spinal degenerative diseases. Percutaneous endoscopic lumbar interbody fusion (PELIF) is a minimally invasive technique that has gained popularity. However, the factors influencing fusion success rates after PELIF have not been well-studied.

Methods

This single-center retrospective study reviewed the medical records of 96 patients who underwent single-level PELIF for degenerative pathologies between 2018 and 2020. Fusion was evaluated using thin-slice computed tomography scans at 12 months by 2 independent radiologists and defined as no detectable lucency between bone and graft. Patients were categorized into fusion and non-fusion groups. Data on age, operative time, blood loss, drainage, hospital stay, surgical level, osteoporosis, endplateitis, body mass index, lumbar curvature, and bone morphogenetic protein (BMP) use were collected. Univariate tests (chi-square, Student’s t-test, and analysis of variance) were employed to compare factors between groups. Significant factors were included in a multivariate logistic regression model with fusion as the dependent variable.

Results

The overall fusion success rate was 85.6% (86 fusion and 10 non-fusion). Univariate analysis revealed significant di!erences in age, osteoporosis, hypertension, diabetes, endplateitis, and BMP use between groups. Multivariate analysis identified osteoporosis (odds ratio (OR)=5.44, 95% CI, P < .05) and end-plate osteochondritis (OR=10.449, 95% CI, P < .05) as independent risk factors for non-fusion.

Conclusion

The use of BMP and endplateitis are significant factors that a!ect bone fusion outcomes after the PELIF procedure. These factors should be taken into account in order to improve postoperative bone fusion.

Level of Evidence

Level IV, Therapeutic Study

Evaluating osteoporosis and bone quality in the aging spine: modern considerations for surgical management in the geriatric population

Surgical management paradigms of spinal pathologies in the aging population carry inherent substantial risks, with surgical complications being more prevalent among patients with osteoporosis compared to those with normal bone mineral density. In this narrative review, we aim to highlight important clinical understanding and considerations in perioperative evaluation and management of patients elected to undergo spinal surgery. Osteoporosis is a well-defined risk factor for mechanical complications following spinal surgery, and as such, perioperative optimization of bone health in the setting of surgery for geriatric patients remains a critical research area alongside intraoperative surgical augmentation techniques. Surgical techniques to circumvent challenges with instrumentation of poor bone mineral density have included augmentation of pedicle screw fixation, including segmental bicortical screw fixation techniques, cement augmentation with fenestrated screws, or use of expandable pedicle screws to improve bone-implant interface. Judicious selection of treatment modalities and subsequent perioperative optimization is paramount to minimize surgical complications. Contemporary guidelines and evolving paradigms in perioperative evaluation, optimization, and management of the aging spine include the advent of quantitatively evaluating computed tomography (CT) via assessment of the magnitude of Hounsfield units. Prescribing pharmacotherapeutic agents and monitoring bone health requires a multidisciplinary team approach, including endocrinologists and geriatricians to coordinate high-quality care for advanced-age patients who require surgical management of their spinal disorders.

Do modic changes affect the fusion rate in spinal interbody fusion surgery? A systematic review and network meta-analysis

OBJECTIVE

To compare the fusion rates of spinal interbody fusion in patients with modic changes (MCs).

METHODS

This meta-analysis was registered at PROSPERO, and the project number was CRD42024538023. This network meta-analysis was conducted according to the PRISMA 2020 statement. The PubMed, Embase, Web of Science Core Collection, ClinicalTrials.gov and Cochrane Library databases were searched from inception to March 28, 2024 for potential studies. STATA 13.0 and Review Manager 5.3 were used to perform the meta-analysis.

RESULTS

Seven studies with a total of 1162 patients or segments assigned to four groups according to MCs grade were identified. The fusion rate in the non-modic changes (NMCs) was significantly greater than that in the MCs at the 3-month (p = 0.0001) and 6-month (p = 0.002) follow-ups. No significant difference was detected in the fusion rate at 12-month (p = 0.34) and final follow-ups (p = 0.41). No significant difference was found in cervical fusion (p = 0.88) or transforaminal lumbar interbody fusion (TLIF) (p = 0.51). The fusion rate of NMCs was significantly greater than that of MCs in posterior lumbar interbody fusion (PLIF) (p < 0.00001). No significant differences were identified among the four groups in the overall comparison, cervical fusion or TLIF subgroups. The fusion rate in the NMCs was significantly greater than that in the MCs-2 and MCs-3 in the PLIF.

CONCLUSION

MCs decreased the fusion rate at the 3- and 6-month follow-ups. MCs-2 and MCs-3 decrease the fusion rate in PLIF.

Effects of anti-osteoporosis treatment in elderly patients with osteoporosis and lumbar discectomy and fusion

BACKGROUND

The effect of anti-osteoporosis treatment in elderly patients with osteoporosis and lumbar discectomy and fusion (LIF) for lumbar degenerative diseases is not well known.

OBJECTIVE

This study aimed to evaluate the effect of perioperative anti-osteoporosis treatment in the patients with osteoporosis and LIF.

METHODS

From January to December 2022, patients were divided into three groups according to the inclusive criteria: the normal group (Group A), the osteopenia group (Group B) and the osteoporosis group (Group C). Quantitative computed tomography (QCT), height of the intervertebral space (HIS), segmental sagittal angle (SSA), visual analogue scale (VAS) score and Oswestry Disability Index (ODI) were compared between the groups at the follow-up time. The serum Ca2 + , osteocalcin (OC), propeptide of type I procollagen (PINP) C-terminal cross-linking telopeptide of type I collagen (β-CTX) and 25-OH vitamin D (25-OH VD) levels were compared between the groups at the time of follow-up. Interbody fusion was graded on the X-ray and CT images at the follow-up time.

RESULTS

There were 165 patients in this study. There were significant differences in the mean age, mean score, HIS and SSA between the groups at the different follow-up times. There were significant differences in the concentrations of serum Ca2 + , OC, β-CTX, 25-OH VD and PINP at the sixth month after surgery between the groups. There were significant differences in the concentrations of serum Ca2 + , β-CTX and 25-OH VD between the pre-surgery and at six months after surgery in Group B and β-CTX and 25-OH VD in Group C. There was a significant difference in the degree of fusion between Group B and C (χ2= 5.6243, P< 0.05).

CONCLUSION

In elderly patients with LIF and osteoporosis, anti-osteoporosis therapy could reduce bone resorption and thus facilitate fusion. Anti-osteoporosis medication tends to enhance radiological, functional, and fusion short-term outcomes.

Patient Optimization for the Prevention of Proximal Junctional Kyphosis

Proximal junctional kyphosis (PJK) and proximal junctional failure (PJF) are well-recognized challenges of surgery for adult spinal deformity (ASD). Multiple risk factors have been identified for PJK/PJF, including osteoporosis, frailty, neurodegenerative disease, obesity, and smoking. Several surgical techniques to mitigate risk of PJK/PJF have been identified; however, patient optimization is also critical. This review summarizes the data behind these 5 risk factors (osteoporosis, frailty, neurodegenerative disease, obesity, and smoking) and details the related recommendations for patients undergoing surgery for ASD.

Does Preoperative Modic Changes Influence the Short-term Fusion Rate of Single Level Transforaminal Lumbar Interbody Fusion?-a Matched-pair Case Control Study

OBJECTIVE

At present, the influence of Modic changes (MCs) on postoperative fusion rate of lumbar interbody fusion (LIF) is mainly focused on the medium- and long-term fusion rate, while the short-term fusion rate has not been reported. The aim of this study was to compare the short-term fusion rate of lumbar degenerative disease patients with and without MCs after single level transforaminal lumbar interbody fusion (TLIF).

METHODS

In this retrospective and matched-pair case control study, we included 100 patients who underwent TLIF from January 2017 to January 2020 and had at least two follow-up visits over a two-year period. Fifty patients with MCs (MCs group) were matched with 50 patients without MCs (non MCs group) for age, sex, surgical level, diagnosis, operative time, and intraoperative blood loss. We collected the X-ray and computed tomography (CT) data of patients from 3 months to 2 years after the operation to assess bony fusion and the cage union ratio. According to the type of cage, the MCs group was further divided into the nano-hydroxyapatite/polyamide 66 (n-HA/PA66) group and polyetheretherketone (PEEK) group, and the fusion performance between the two groups was compared. Finally, age, sex, body mass index (BMI), smoking and cage type were included in the logistic regression model for risk factor analysis.

RESULTS

The bony fusion rates in the MCs group at 3 months, 6 months, 1 year and 2 years after surgery were significantly lower than those in the non MCs group (P < 0.05) (23.8% vs 62.5%, 52.6% vs 78.9%, 61.1% vs 83.3%, 74.0% vs 90.0%). The average coronal cage union ratios of the upper and lower endplates in the MCs group were significantly lower than those in the non MCs group (54.3% ± 17.5% vs 75.0% ± 17.2%, P < 0.05; 73.3% ± 12.0% vs 84.9% ± 8.0%, P < 0.05). Similarly, analogous results were obtained by comparing the MCs and non MCs groups' three-dimensional CT sagittal plane images (62.5% ± 16.5% vs 76.1% ± 12.4%, P < 0.05; 67.0% ± 13.9% vs 79.8% ± 11.5%, P < 0.05).

CONCLUSION

Short-term fusion rates were lower in the MCs group than in the non MCs group. The coronal and sagittal cage union ratio in the MCs group was lower than that in the non MCs group. The fusion performance of n-HA/PA66 and PEEK cages in the MCs group was comparable.

Medical optimization of osteoporosis for adult spinal deformity surgery: a state-of-the-art evidence-based review of current pharmacotherapy

PURPOSE

Osteoporosis is a common, but challenging phenomenon to overcome in adult spinal deformity (ASD) surgery. Several pharmacological agents are at the surgeon's disposal to optimize the osteoporotic patient prior to undergoing extensive reconstruction. Familiarity with these medications will allow the surgeon to make informed decisions on selecting the most appropriate adjuncts for each individual patient.

METHODS

A comprehensive literature review was conducted in PubMed from September 2021 to April 2022. Studies were selected that contained combinations of various terms including osteoporosis, specific medications, spine surgery, fusion, cage subsidence, screw loosening, pull-out, junctional kyphosis/failure.

RESULTS

Bisphosphonates, denosumab, selective estrogen receptor modulators, teriparatide, abaloparatide and romosozumab are all pharmacological agents currently available for adjunctive use. While these medications have been shown to have beneficial effects on improving bone mineral density in the osteoporotic patient, varying evidence is available on their specific effects in the context of extensive spine surgery. There is still a lack of human studies with use of the newer agents.

CONCLUSION

Bisphosphonates are first-line agents due to their low cost and robust evidence behind their utility. However, in the absence of contraindications, optimizing bone quality with anabolic medications should be strongly considered in preparation for spinal deformity surgeries due to their beneficial and favorable effects on fusion and hardware compared to the anti-resorptive medications.

Timing of osteoporosis therapies following fracture: the current status

In most patients, osteoporosis is diagnosed only after the occurrence of the first fragility fracture. It is of utmost importance to start osteoporosis medications immediately in these patients to prevent future fractures and also to reduce associated mortality and morbidity. There remains a hesitancy over initiating osteoporotic medications, specifically for antiresorptive agents like bisphosphonates following an acute fracture due to concern over their effect on fracture healing. The purpose of this review is to study the effect of the timing of initiation of different osteoporosis medications on healing after an acute fracture. Most of the human studies, including randomized control trials (RCTs), did not find any significant negative effect on fracture healing with early use of bisphosphonate after an acute fracture. Anabolic agents like teriparatide have shown either neutral or beneficial effects on fracture healing and thus can be started very early following any osteoporotic fracture. Although human studies on the early use of other osteoporosis medications like denosumab or strontium ranelate are very sparse in the literature, none of these medications have shown any evidence of delay in fracture healing. To summarize, among the commonly used anti-osteoporosis agents, both bisphosphonates and teriparatide are safe to be initiated in the early acute post-fracture period. Moreover, teriparatide has shown some evidence in favor of reducing fracture healing time.

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.

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.

Clinical and radiographic outcomes of hybrid graft in patients with Modic changes undergoing transforaminal lumbar interbody fusion

Background

This retrospective study aimed to analyze the influence of Modic changes (MCs) on the clinical and radiographic outcomes of transforaminal lumbar interbody fusion with hybrid graft.

Methods

Clinical data of 89 patients with Modic changes who underwent single-segment transforaminal lumbar interbody fusion between January 2015 and January 2019 at our institution were analyzed. Patients were divided into three groups: the MCs-0 group (no endplate changes; used as the control group), the MCs-1 group, and the MCs-2 group. Clinical and radiological parameters were compared between the three groups.

Results

There were no significant between-group differences in age (P = 0.216), sex (P = 0.903), body mass index (P = 0.805), smoking (P = 0.722), diagnosis (P = 0.758), surgical level (P = 0.760), blood loss (P = 0.172), operative time (P = 0.236), or follow-up (P = 0.372). Serum C-reactive protein level and erythrocyte sedimentation rate in the MCs-1 and MCs-2 groups were significantly higher than those in the MCs-0 group on the third and seventh days (P < 0.05). Postoperative radiographic parameters were significantly higher than preoperative parameters in all 3 groups (P < 0.05). Visual analog scale scores for low back pain in the MCs-0 and MCs-2 groups were significantly different from those in the MCs-1 group (P < 0.05). However, there were no significant between-group differences with respect to Oswestry Disability Index scores or visual analog scale scores for leg pain.

Conclusion

In this study, Modic changes had no impact on fusion rates and clinical outcomes of transforaminal lumbar interbody fusion with hybrid graft (autologous local bone graft plus allogeneic freeze-dried bone graft). However, MCs-1 increased the risk of cage subsidence and showed superior outcomes in terms of visual analog scale scores for low back pain.

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.

Influence of Modic Changes on Cage Subsidence and Intervertebral Fusion after Single-Level Anterior Cervical Corpectomy and Fusion

OBJECTIVES

This retrospective study aimed to determine the impact of Modic changes (MCs) on cage subsidence (CS) and intervertebral fusion after anterior cervical corpectomy and fusion (ACCF).

METHODS

This study enrolled 61 patients with MCs who underwent single-level ACCF between January 2010 and December 2015 at our institution. The control group included 63 age-matched patients without MCs treated during the same period. The results from clinical and radiological assessments were reviewed, and radiographic CS was defined by an intervertebral height at the final follow-up that was less than the postoperative intervertebral height.

RESULTS

No significant differences in gender, age, operative time, blood loss, or follow-up results were observed between the MCs and control groups. Significantly more patients experienced CS in the MCs group than in the control group (41.0% vs. 15.9%; p = 0.003). The frequencies of CS among patients with type I MCs (40.0%, 8/20) and type II MCs (41.5%, 17/41) were significantly higher than that in the control group (15.9%, 10/63; p < 0.05). Both groups showed significant improvements in clinical assessment scores after surgery and at final follow-up compared with preoperative values (p < 0.05).

CONCLUSION

In summary, all 61 patients with MCs who underwent ACCF achieved good fusion results. MCs in the surgical segment had no significant effect on intervertebral fusion, but both type 1 and type 2 MCs may increase the risk of CS.

Teriparatide and bisphosphonate use in osteoporotic spinal fusion patients: a systematic review and meta-analysis

PURPOSE

Osteoporosis is one of the most common conditions among adults worldwide. It also presents a challenge among patients undergoing spinal surgery. Use of Teriparatide and bisphosphonates in such patients has been shown to improve outcomes after fusion surgery, including successful fusion, decreased risk of instrumentation failure, and patient-reported outcomes. Herein, we performed a systematic review and indirect meta-analysis of available literature on outcomes of fusion surgery after use of bisphosphonates or Teriparatide.

METHODS

We conducted a comprehensive search of all databases (Ovid MEDLINE(R) and Epub Ahead of Print, In-Process & Other Non-Indexed Citations, Ovid Embase, Ovid Cochrane Central Register of Controlled Trials, Ovid Cochrane Database of Systematic Reviews, and Scopus) to identify studies assessing outcomes of spinal fusion among osteoporotic patients after use of Teriparatide or bisphosphonate. Four authors independently screened electronic search results, and all four authors independently performed study selection. Two authors performed independent data extraction and assessed the studies' risk of bias assessment using standardized forms of Revised Cochrane risk-of-bias tool for randomized trials (RoB 2) and Risk Of Bias In Non-randomized Studies of Interventions (ROBINS-I).

RESULTS

Nineteen studies were included in the final analysis. A total of 13 studies evaluated the difference in fusion rate between bisphosphonates and Teriparatide or control group. Fusion rate was higher for bisphosphonates (effect size (ES) 83%, 95% CI 77-89%) compared with Teriparatide (ES 71%, 95% CI 57-85%), with the p value for heterogeneity between groups without statistical significance (p = 0.123). Five studies assessed the impact of using bisphosphonate or Teriparatide on screw loosening. The rate of screw loosening was higher for bisphosphonates (ES 19%, 95% CI 13-25%) compared with Teriparatide (ES 13%, 95% CI 9-16%) without statistical significance (p = 0.52).

CONCLUSION

Our results indicate that while both agents may be associated with positive outcomes, bisphosphonates may be associated with a higher fusion rate, while Teriparatide may be associated with lower screw loosening. The decision to treat with either agent should be tailored individually for each patient keeping in consideration the adverse effect and pharmacokinetic profiles.

Does the use of preoperative bisphosphonates in patients with osteopenia and osteoporosis affect lumbar fusion rates? Analysis from a national spine registry

OBJECTIVE

Bisphosphonates are used to increase bone strength in treating osteopenia and osteoporosis, but their use for increasing lumbar fusion rates has been controversial. The objective of this study was to determine if preoperative treatment with bisphosphonates affects the reoperation rates for nonunions (operative nonunion rates) following lumbar fusions in patients with osteopenia or osteoporosis.

METHODS

The authors conducted a cohort study using data from the Kaiser Permanente Spine Registry. Patients (aged ≥ 50 years) with a diagnosis of osteopenia or osteoporosis who underwent primary elective lumbar fusions for degenerative disc disease, deformity, or spondylolisthesis were included in the cohort. Repeated spinal procedures at the index lumbar levels were noted through chart review. Reoperations for symptomatic nonunions (operative nonunions), time to nonunion, and the nonunion spine level(s) were also identified. The crude 2-year cumulative incidence of operative nonunions was calculated as 1 minus the Kaplan-Meier estimator. Cox proportional hazard regression was used to evaluate the association between preoperative bisphosphonate use and operative nonunion after adjustment for covariates. Analysis was stratified by osteopenia and osteoporosis diagnosis.

RESULTS

The cohort comprised 1040 primary elective lumbar fusion patients, 408 with osteopenia and 632 with osteoporosis. Ninety-seven (23.8%) patients with osteopenia and 370 (58.5%) patients with osteoporosis were preoperative bisphosphonate users. For the osteopenia group, no operative nonunions were observed in patients with preoperative bisphosphonate, while the crude 2-year incidence was 2.44% (95% CI 0.63–4.22) in the nonuser group. For the osteoporotic group, after adjustment for covariates, no difference was observed in risk for operative nonunions between the preoperative bisphosphonate users and nonusers (HR 0.96, 95% CI 0.20–4.55, p = 0.964).

CONCLUSIONS

To the authors’ knowledge, this study presents one of the largest series of patients with the diagnosis of osteopenia or osteoporosis in whom the effects of preoperative bisphosphonates on lumbar fusions were evaluated using operative nonunion rates as an outcome measure. The results indicate that preoperative bisphosphonate use had no effect on the operative nonunion rates for patients with osteoporosis. Similar indications were not confirmed in osteopenia patients because of the low nonunion frequency. Further studies are warranted to the determine if preoperative and postoperative timing of bisphosphonate use has any effect on lumbar fusion rates.

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.

Effects of menopausal state on lumbar decompression and fusion surgery

Menopause leads to fluctuations in androgenic hormones which directly affect bone metabolism. Bone resorption, mineralization, and remodeling at fusion sites are essential in order to obtain a solid and biomechanically stable fusion mass. Bone metabolic imbalance seen in the postmenopausal state may predispose to fusion related complications. The aim of this study was to investigate fusion outcomes in lumbar spinal fusion surgery in women based on menopausal status. A retrospective analysis of all female patients who underwent posterior lumbar decompression and fusion at a single institution from 2013 to 2017 was performed. A total of 112 patients were identified and stratified into premenopausal (n = 25) and postmenopausal (n = 87) groups. Clinical and radiographic data was assessed at 1 year follow up. Postmenopausal patients had a higher rates of pseudarthrosis (11.63% vs 0%, p = 0.08), PJK (15.1% vs 4%, p = 0.14), and revision surgery (3.5% vs 0%, p = 0.35). The number of levels fused was associated with increased risk of pseudarthrosis (OR 1.4, p = 0.02); however, there was no association between age, hormonal use, prior tobacco use, or T-score. Age was associated with increased risk of developing PJK (OR = 1.11, p = 0.01); however, PJK was not associated with menopause, hormonal use, prior tobacco use, or T-score. Revision surgery was not associated with age, hormonal use, prior tobacco use, or T-score. This study suggests that postmenopausal women may be prone to have higher rates of pseudarthrosis, PJK and revision surgery, although our results were not statistically significant. Larger studies with longer follow up will help elucidate the true effects of menopause in spine surgery.

The effects of bisphosphonates on osteoporotic patients after lumbar fusion: a meta-analysis

Purpose

We conducted a meta-analysis of controlled clinical trials to evaluate the efficacy of bisphosphonates in lumbar fusion.

Introduction

Bisphosphonates reduce bone resorption and remodeling by osteoclast activity inhibition, inactivation, and apoptosis. However, it remains controversial whether bisphosphonate therapy affects spinal fusion.

Methods

We searched MEDLINE, Cochrane CENTRAL, ScienceDirect, EMBASE, and Google Scholar to identify studies reporting the effects of bisphosphonates on osteoporotic patients after lumbar fusion. Secondary sources were identified from the references of the included literature. Pooled data were analyzed using RevMan 5.1.

Results

Seven studies met the inclusion criteria. There were significant differences in solid intervertebral fusion (RD=0.07, 95% CI: −0.00 to 0.15, P=0.05), subsequent VCFs (RD=−0.21, 95% CI: −0.30 to −0.12, P<0.00001), pedicle screw loosening (RD=−0.17, 95% CI: −0.28 to −0.05, P=0.006), and cage subsidence (RD=−0.25, 95% CI: −0.42 to −0.07, P=0.005) between two groups. No significant differences between two groups were found regarding implant fixation failure (RD=−0.06, 95% CI: −0.22 to 0.10, P=0.48).

Conclusion

This meta-analysis showed that bisphosphonates may increase solid intervertebral fusion and decrease subsequent VCFs, pedicle screw loosening, and cage subsidence.

Medical optimization of lumbar fusion in the osteoporotic patient

PURPOSE

In patients undergoing lumbar fusion, osteoporosis has been shown to lead to poorer outcomes and greater incidence of fusion-related complications. Given the undesirable effect of osteoporosis on lumbar fusion surgery, a number of medications have been proposed for use in the peri- and postoperative period to mitigate risks and enhance outcomes. The purpose of this review was to summarize and synthesize the current literature regarding medical management of osteoporosis in the context of lumbar fusion surgery.

METHODS

A literature search of PubMed, Embase, and Web of Science was conducted in October 2016, using permutations of various search terms related to osteoporosis, medications, and lumbar fusion.

RESULTS

Teriparatide injections may lead to faster, more successful fusion, and may reduce fusion-related complications. Bisphosphonate therapy likely does not hinder fusion outcomes and may be useful in reducing certain complications of fusion in osteoporotic patients. Calcitonin and selective estrogen receptor modulator therapy show mixed results, but more research is necessary to make a recommendation. Vitamin D deficiency is associated with poor fusion outcomes, but evidence for supplementation in patients with normal serum levels is weak.

CONCLUSIONS

Overall, the current body of research appears to support the use of teriparatide therapy to enhance lumbar fusion outcomes in the osteoporotic patient, although the extent of research on this topic is limited. Additionally, very little evidence exists to cease any of the mentioned osteoporosis treatments prior to lumbar fusion.

Bisphosphonate's and Intermittent Parathyroid Hormone's Effect on Human Spinal Fusion: A Systematic Review of the Literature

There has been a conscious effort to address osteoporosis in the aging population. As bisphosphonate and intermittent parathyroid hormone (PTH) therapy become more widely prescribed to treat osteoporosis, it is important to understand their effects on other physiologic processes, particularly the impact on spinal fusion. Despite early animal model studies and more recent clinical studies, the impact of these medications on spinal fusion is not fully understood. Previous animal studies suggest that bisphosphonate therapy resulted in inhibition of fusion mass with impeded maturity and an unknown effect on biomechanical strength. Prior animal studies demonstrate an improved fusion rate and fusion mass microstructure with the use of intermittent PTH. The purpose of this study was to determine if bisphosphonates and intermittent PTH treatment have impact on human spinal fusion. A systematic review of the literature published between 1980 and 2015 was conducted using major electronic databases. Studies reporting outcomes of human subjects undergoing 1, 2, or 3-level spinal fusion while receiving bisphosphonates and/or intermittent PTH treatment were included. The results of relevant human studies were analyzed for consensus on the effects of these medications in regards to spinal fusion. There were nine human studies evaluating the impact of these medications on spinal fusion. Improved fusion rates were noted in patients receiving bisphosphonates compared to control groups, and greater fusion rates in patients receiving PTH compared to control groups. Prior studies involving animal models found an improved fusion rate and fusion mass microstructure with the use of intermittent PTH. No significant complications were demonstrated in any study included in the analysis. Bisphosphonate use in humans may not be a deterrent to spinal fusion. Intermittent parathyroid use has shown early promise to increase fusion mass in both animal and human studies but further studies are needed to support routine use.

Atypical Complete Femoral Fractures Associated with Bisphosphonate Use or Not Associated with Bisphosphonate Use: Is There a Difference?

The purpose of this study is to compare clinical characteristics and surgical outcome of atypical complete femoral fractures associated with bisphosphonates (BPs) use and those of fractures not associated with BPs use. Seventy-six consecutive patients (81 fractures) who had been operatively treated for a complete atypical femoral fracture were recruited. Of the 81 fractures, 73 occurred after BPs medication of at least 3 years (BP group) while 8 occurred without a history of BP medication (non-BP group). There were no differences in demographic data and fracture- and surgery-associated factors between the two groups. Of 76 patients (81 fractures), 54 (66.7%) fractures showed bony union within 6 months after the index surgery and 23 (28.4%) showed delayed union at a mean of 11.2 months (range, 8–18 months). The remaining 4 fractures were not healed, even 18 months after the index surgery. There was no difference in healing rate between the BP group and the non-BP group. There were strong correlations between the fracture height and the degree of bowing regardless of BPs medication. All fractures except 1 occurred at the diaphyseal region of the femur when not associated with BP medication.

A Systematic Review of Treatment Strategies for Degenerative Lumbar Spine Fusion Surgery in Patients With Osteoporosis

Purpose:

To evaluate the current evidence in the literature on treatment strategies for degenerative lumbar spine fusion in patients with osteoporosis.

Methods:

A systematic review of the literature from 1950 to 2015.

Results:

The review of the literature yielded 15 studies on the effect of treatment options for osteoporosis on lumbar fusion rates. This study evaluated only degenerative lumbar spine conditions and excluded deformity patients. One study demonstrated an association between low bone mass as measured by Hounsfield units and lower fusion rates. Six studies evaluated perioperative medical treatment of osteoporosis and showed higher fusion rates in patients treated with alendronate and teriparatide. The strongest evidence was for perioperative teriparatide. Eight studies evaluated surgical treatment strategies in patients with osteoporosis and showed that cement augmentation of pedicle screws and expandable pedicle screws demonstrated improved fusion rates than traditional pedicle screws. The strongest evidence was for expandable pedicle screws.

Conclusion:

There are 15 articles evaluating osteoporosis in patients undergoing lumbar fusion and the highest level of evidence is for perioperative use of teriparatide.