Retrospective radiological outcome analysis following teriparatide use in elderly patients undergoing multilevel instrumented lumbar fusion surgery

Intraoperative Surgeon Assessment of Bone: Correlation to Bone Mineral Density, CT Hounsfield Units, and Vertebral Bone Quality

STUDY DESIGN

Retrospective observational study of consecutive patients.

OBJECTIVE

The purpose of the study is to determine if a surgeon's qualitative assessment of bone intraoperatively correlates with radiologic parameters of bone strength.

SUMMARY OF BACKGROUND DATA

Preoperative radiologic assessment of bone can include modalities such as computed tomography (CT) Hounsfield units (HUs), dual-energy x-ray absorptiometry (DXA) bone mineral density with trabecular bone score (TBS) and magnetic resonance imaging vertebral bone quality (VBQ). Quantitative analysis of bone with screw insertional torque and pull-out strength measurement has been performed in cadaveric models and has been correlated to these radiologic parameters. However, these quantitative measurements are not routinely available for use in surgery. Surgeons anecdotally judge bone strength, but the fidelity of the intraoperative judgment has not been investigated.

METHODS

All adult patients undergoing instrumented posterior thoracolumbar spine fusion by one of seven surgeons at a single center over a 3-month period were included. Surgeons evaluated the strength of bone based on intraoperative feedback and graded each patient's bone on a 5-point Likert scale. Two independent reviewers measured preoperative CT HUs and magnetic resonance imaging VBQ. Bone mineral density, lowest T-score, and TBS were extracted from DXA within 2 years of surgery.

RESULTS

Eighty-nine patients were enrolled and 16, 28, 31, 13, and 1 patients had Likert grade 1 (strongest bone), 2, 3, 4, and 5 (weakest bone), respectively. The surgeon assessment of bone correlated with VBQ (τ=0.15, P =0.07), CT HU (τ=-0.31, P <0.01), lowest DXA T-score (τ=-0.47, P <0.01), and TBS (τ=-0.23, P =0.06).

CONCLUSION

Spine surgeons' qualitative intraoperative assessment of bone correlates with preoperative radiologic parameters, particularly in posterior thoracolumbar surgeries. This information is valuable to surgeons as this supports the idea that decisions based on feel in surgery have a statistical foundation.

Preoperative Optimization for Adult Spinal Deformity Surgery: A Systematic Review

STUDY DESIGN

Systematic review.

OBJECTIVE

The purpose of this review is to identify modifiable risk factors in patients undergoing adult spinal deformity surgery and compile literature recommendations for the preoperative optimization of these risk factors.

SUMMARY OF BACKGROUND DATA

Optimization of modifiable risk factors not only benefits the patient but also lessens resource and cost burdens on the health care system, allowing for better quality and value-based care. There is limited but applicable literature discussing preoperative optimization in adult spinal deformity surgery patients specifically.

METHODS

We searched PubMed for studies that looked at one of the variables of interest (eg, osteoporosis, prehabilitation and functional status, multidisciplinary preoperative screening, infection, obesity, nutrition, smoking, diabetes, blood loss, chronic opioid use, and psychosocial factors) in adult patients with spinal deformity according to Preferred Reporting Items for Systematic Reviews and Meta-Analyse guidelines.

RESULTS

Seventy studies were included in the final review and synthesis of information. Guidelines and recommendations from these studies were compared and compiled into evidence-based action items for preoperative optimization of modifiable risk factors before adult spinal deformity surgery.

CONCLUSIONS

While the approach of preoperative optimization of modifiable risk factors may incur additional planning efforts and patient care time, it has the potential to significantly reduce perioperative complications and reduce morbidity and mortality during surgery, thus allowing for improved outcomes, increased quality of life, and satisfaction from this patient population.

LEVEL OF EVIDENCE

3.

The Significance of Combined OSTA, HU Value and VBQ Score in Osteoporosis Screening Before Spinal Surgery

OBJECTIVE

This study aimed to assess the utility of a combined assessment using the Osteoporosis Self-Assessment Tool for Asians (OSTA), Hounsfield unit (HU) value, and vertebral bone quality (VBQ) score for preoperative osteoporosis (OP) screening in patients scheduled for spinal surgery.

METHODS

This study encompassed 288 participants, including 128 males and 160 females. Patients were stratified into 2 groups: the OP group (T-score ≤ -2.5) and the non-OP group (T-score > -2.5), determined by dual-energy X-ray absorptiometry (DEXA). Binary logistic regression was used to construct a combined diagnostic model, and the receiver operating characteristic (ROC) curve evaluated the sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) of these metrics individually or in combination to screen for OP.

RESULTS

Osteoporosis patients exhibited significantly lower OSTA and HU values in comparison to non-OP patients, while their VBQ scores were significantly higher (P < 0.001). The ROC curve analysis results indicated that within the male group, the combined diagnosis had a sensitivity of 93.8%, specificity of 82.3%, accuracy of 85.2%, PPV of 63.8%, and NPV of 97.5%. In the female group, the combined diagnosis had a sensitivity of 93.9%, specificity of 87.4%, accuracy of 90.0%, PPV of 83.6%, and NPV of 95.4%.

CONCLUSIONS

The combined use of OSTA, HU values, and VBQ scores in preoperative OP screening for spinal surgery demonstrates significantly higher accuracy and superior screening value compared to individual assessments. These results establish a robust scientific foundation for conducting preoperative OP screening in patients undergoing spinal surgery.

Effectiveness of Teriparatide for Spine Fusion in Osteoporotic Patient: A Systematic Review and Meta-Analysis of Comparative Studies

OBJECTIVE

Our goal was to assess teriparatide's (TP) effectiveness in improving radiographic and functional outcomes after spinal fusion surgery. This meta-analysis included randomized controlled trials (RCTs) and comparative cohort studies. The findings provide valuable insights and guidance for surgeons treating osteoporotic patients undergoing spinal fusion surgery.

METHODS

We conducted a systematic review to assess TP's efficacy in spinal fusion surgery for osteoporosis. Through thorough selection, data extraction, and quality assessment, we employed network meta-analysis to evaluate radiographic outcomes (fusion rate, screw loosening, vertebral fracture) and changes in bone mineral density measured by Hounsfield units. Functional outcomes were assessed using the Oswestry Disability Index scales. Our study aims to comprehensively understand TP's impact and effectiveness in spinal fusion surgery.

RESULTS

A total of 868 patients were included in the analysis. All patients underwent thoracolumbar internal fixation fusion surgery and were divided into following 2 groups: the TP treatment group and the control group. The results revealed significant differences in radiological outcomes. The fusion rate showed a significant difference, as well as screw loosening, and bone mineral density measured in Hounsfield units. However, there was no significant difference in vertebral fracture. The TP group demonstrated favorable effects with statistical significance. In terms of functional outcomes, there was no significant difference in the assessment of Oswestry Disability Index scores between the 2 treatment groups.

CONCLUSIONS

The meta-analysis demonstrated that the TP group exhibited significantly better outcomes, particularly in radiological measures, when compared to the control group. The use of TP in spinal fusion surgery shows promise in reducing postoperative complications and providing overall benefits.

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.

Effects of local single dose administration of parathormone on the early stages of osseointegration: A pre-clinical study

The present study aimed to evaluate the effect of parathormone (PTH) administered directly to the implant's surface prior to insertion, using a large translational animal model. Sixty titanium implants were divided into four groups: (i) Collagen, control group, where implants were coated with Type-I Bovine-collagen, and three experimental groups, where implants received varying doses of PTH: (ii) 12.5, (iii) 25, and (iv) 50 μg, prior to placement. Fifteen female sheep (~2 years old, weighing ~65 kg) received four implants in an interpolated fashion in C3, C4 or C5 vertebral bodies. After 3-, 6- and 12-weeks, samples were harvested, histologically processed, qualitatively and quantitatively assessed for bone-to-implant contact (BIC) and bone area fraction occupancy (BAFO). BIC yielded lower values at 6-weeks for 50 μg relative to the control group, with no significant differences, when compared to the 12.5- and 25-μg. No significant differences were detected at 6-weeks between collagen, 12.5- and 25-μg groups. At 3- and 12-weeks, no differences were detected for BIC among PTH groups. With respect to BAFO, no significant differences were observed between the control and experimental groups independent of PTH concentration and time in vivo. Qualitative observations at 3-weeks indicated the presence of a more mature bone near the implant's surface with the application of PTH, however, no significant differences in new bone formation or healing patterns were observed at 6- and 12-weeks. Single local application of different concentrations of PTH on titanium implant's surface did not influence the osseointegration at any time-point evaluation in low-density bone.

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.

The Effect of Daily Teriparatide versus One-Time Annually Zoledronic Acid Administration After Transforaminal Lumbar Interbody Fusion in Osteoporotic Patients

Purpose

The research aimed to compare the therapeutic effect of teriparatide (TPTD) and zoledronic acid (ZOL) therapy on bone formation and spinal fusion in patients with osteoporosis (OP) who underwent transforaminal lumbar interbody fusion (TLIF).

Methods

On the basis of different anti-OP treatment options, the TPTD group was treated daily with TPTD (20 μg. ih. qd) for at least 6 months, while the ZOL group was treated with a single dose of ZOL (5 mg. ivgtt. st) postoperatively. The visual analogue scale (VAS), Oswestry Disability Index (ODI), bone mineral density (BMD), and concentration of bone turnover markers before, 6, and 12 months after surgery were evaluated. X-ray and three-dimensional computed tomography scans were performed at 6 and 12 months postoperatively to assess interbody fusion.

Results

The number of patients in the TPTD and ZOL groups was 29 and 38 patients, respectively. The VAS and ODI scores in both groups were significantly reduced at 6 and 12 months after TLIF. Compared with that of baseline, the lumbar spine BMD of TPTD patients increased significantly from 0.716±0.137 g/cm² to 0.745±0.124 g/cm² and 0.795±0.123 g/cm² at 6 and 12 months, respectively, and was significantly higher than that of the ZOL group at 12 months (0.720±0.128 g/cm²). The bone formation marker, P1NP, in the TPTD group increased significantly (145.48±66.64 ng/mL and 119.55±88.27 ng/mL) compared with baseline (44.67±25.15 ng/mL) and in the ZOL group (28.82±19.76 ng/mL and 29.94±20.67 ng/mL) at 6 and 12 months, respectively. The fusion rates in the TPTD and ZOL groups were 57% and 45% at 6 months, without statistical significance. However, TPTD had a more statistically significant positive influence on fusion rate than ZOL at 12 months (86% vs 70%).

Conclusion

TPTD was more efficient than ZOL in bone formation and spinal fusion in OP patients who underwent TLIF.

Teriparatide Treatment Increases Hounsfield Units in the Thoracic Spine, Lumbar Spine, Sacrum, and Ilium Out of Proportion to the Cervical Spine

STUDY DESIGN

This was a retrospective chart review.

OBJECTIVE

The objective of this study was to compare the effect of teriparatide on Hounsfield Units (HU) in the cervical spine, thoracic spine, lumbar spine, sacrum, and pelvis. Second, to correlate HU changes at each spinal level with bone mineral density (BMD) on dual-energy x-ray absorptiometry (DXA).

SUMMARY OF BACKGROUND DATA

HU represent a method to estimate BMD and can be used either separately or in conjunction with BMD from DXA.

MATERIALS AND METHODS

A retrospective chart review included patients who had been treated with at least 6 months of teriparatide. HU were measured in the vertebral bodies of the cervical, thoracic, and lumbosacral spine and iliac crests. Lumbar and femoral neck BMD as measured on DXA was collected when available.

RESULTS

One hundred twenty-five patients were identified for analysis with an average age of 67 years who underwent a mean (±SD) of 22±8 months of teriparatide therapy. HU improvement in the cervical spine was 11% (P=0.19), 25% in the thoracic spine (P=0.002), 23% in the lumbar spine (P=0.027), 17% in the sacrum (P=0.11), and 29% in the iliac crests (P=0.09). Lumbar HU correlated better than cervical HU with BMD as measured on DXA.

CONCLUSIONS

Teriparatide increased average HU in the thoracolumbar spine to a proportionally greater extent than the cervical spine. The cervical spine had a higher baseline starting HU than the thoracolumbar spine. Lumbar HU correlated better than cervical and thoracic HU with BMD as measured on DXA.

Therapeutic Effect of Teriparatide for Osteoporotic Thoracolumbar Burst Fracture in Elderly Female Patients

Objective

Teriparatide is known as an effective anabolic agent not only for severe osteoporosis but also for bone healing and union. We explored the possibility of teriparatide as an alternative treatment option for osteoporotic thoracolumbar (TL) burst fracture.

Methods

This retrospective study enrolled 35 female patients with mean age of 73.77±6.71 years (61–88) diagnosed as osteoporotic TL burst fracture with ≥4 of thoracolumbar injury classification and severity (TLICS) score and no neurological deficits. All patients were treated by teriparatide only (12 of group A), teriparatide plus vertebroplasty (12 of group B), or surgical fixation with fusion (11 of group C), and followed up for 12 months. Radiological outcomes were evaluated using radiological parameters including kyphotic angle (KA), segmental vertebral kyphotic angle (SVKA), compression ratio (CR), and vertebral body height (anterior [AH], middle [MH], posterior [PH]). Functional outcomes were evaluated using visual analog scale (VAS) and Macnab classification (MC).

Results

There were no statistical significant differences in age, bone mineral density (-3.36±0.73), and TLICS score (4.34±0.48) among the three groups (p>0.05). Teriparatide was administered during 8.63±2.32 months in group A and B. In 12-month radiological outcomes, there were significant restoration in SVKA, CR, AH, and MH of group B and KA, SVKA, CR, AH, and MH of group C compared to group A with no radiological changes (p<0.05). All groups showed similar significant improvements in 12-month functional outcomes, although group B and C showed a better 1-month VAS, 1-month MC, 3-month MC compared to group A (p<0.05).

Conclusion

Non-surgical treatment with teriparatide showed similar 12-month functional outcomes compared to surgical fixation with fusion. The additional vertebroplasty to teriparatide and surgical fixation with fusion were more helpful to improve short-term functional outcomes with structural restoration compared to teriparatide only.

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.

Use of teriparatide prior to lumbar fusion surgery lowers two-year complications for patients with poor bone health

INTRODUCTION

Poor bone health can create challenges in management which are amplified for patients undergoing spinal fusion. Although previously shown to improve outcomes postoperatively, the impact of preoperative teriparatide use on long-term complications remains unclear. In this study, we investigated the complication rates within two years of surgery for osteoporotic and osteopenic patients using teriparatide prior to lumbar fusion procedures.

METHODS

Patients with poor bone health undergoing any lumbar fusion surgery at a single institution between 2008 and 2018 were identified and subsequently divided into two groups as teriparatide and non-teriparatide group. Baseline demographics, patient and surgery related factors, and two-year complications were collected through a retrospective chart review. Multivariable logistic regression was performed to evaluate the association between teriparatide usage and development of any related postoperative complication.

RESULTS

A total of 42 and 114 patients were identified for the teriparatide and non-teriparatide groups, respectively. The median age (IQR) for the teriparatide group was 62 years (55.8-68.8), while the non-teriparatide group had a median (IQR) age of 70 years (64-75.8). Overall, there were no statistically significant differences in terms of individual complications between the groups. However, on adjusted regression analysis, teriparatide use was associated with significantly lower odds of related complications for lumbar fusion patients (p = 0.049).

CONCLUSION

Teriparatide use prior to lumbar fusion procedures resulted in reduced rate of osteoporosis-related complications within two years postoperatively. Results suggest improved outcomes might be seen in patients with osteopenia and osteoporosis when pre-treating with teriparatide.

Assessment of the efficacy of teriparatide treatment for osteoporosis on lumbar fusion surgery outcomes: a systematic review and meta-analysis

Treatment of osteoporosis with medications like teriparatide, a parathyroid hormone, is known to improve bone density and reduce the risk of osteoporotic vertebral fractures. Anecdotal and limited surgical series have described the utility of this treatment for osteoporotic patients prior to spinal fusion surgery, but there is variability in adoption of this strategy as well as consensus regarding optimal treatment duration before and after surgery. In this study, the clinical results of the use of teriparatide for this application are reviewed and critically examined. We conducted a systematic review of electronic databases using different MeSH terms from 1980 to 2020. Pooled and subgroup analyses were performed using fixed and random effect models based upon the heterogeneity (I²). The results were reported as either mean difference (MD) or odds ratio (OR) with 95% confidence interval (CI). A total of 771 patients from 12 studies were identified. Three hundred seventy-seven patients (90.8% females) were treated with teriparatide. Lumbar spinal fusion rates were significantly higher among patients who received teriparatide compared to the non-teriparatide group (OR 2.15, 95%CI 1.56-2.97, p < 0.00001). Subgroup analysis revealed that patients receiving teriparatide demonstrated 2.12-fold and 2.23-fold higher likelihood of fusion compared to those in the bisphosphonate (OR 2.12, 95%CI 1.45-3.11, p = 0.0001) and placebo (OR 2.23, 95%CI 1.22-4.08, p = 0.009) cohorts, respectively. The treatment effect of teriparatide was associated with significantly reduced subsequent vertebral fractures (OR 0.16, 95%CI 0.06-0.41, p = 0.0002), sagittal malalignment (MD - 3.85, 95%CI: -6.49 to - 1.21, p = 0.004), limb visual analogue score (VAS) (MD - 0.36, 95%CI - 0.64 to - 0.09, p = 0.008), and spinal VAS (MD - 0.24, 95%CI - 0.44 to - 0.04, p = 0.02) compared to the non-teriparatide group. Patients using teriparatide had 30% less likelihood of screw loosening at last follow-up compared to the non-teriparatide group; however, this was not statistically significant (OR 0.70, 95%CI 0.43-1.14, p = 0.15). There did not exist any statistically significant difference between the two comparative groups in terms of pseudoarthrosis (OR 0.54, 95%CI 0.24-1.21, p = 0.13), cage subsidence (OR 1.30, 95%CI 0.38-4.52, p = 0.68), and bone mineral density (MD 0.04, 95%CI - 0.19-0.29, p = 0.74) at last follow-up examination. This meta-analysis corroborates the effectiveness of teriparatide resulting in higher fusion rates. Further study is required to determine the optimal duration of treatment and timing of surgery.

Abaloparatide and the Spine: A Narrative Review

Osteoporosis is a common and debilitating condition characterized by diminished bone mass and architecture leading to bone fragility. Antiresorptive medicines like bisphosphonates (and less commonly denosumab) are the typical first-line agents for the medical treatment of osteoporosis. However, newer anabolic agents have been shown to improve bone mass and architecture, as well as reduce fracture risk, to a greater degree than traditional antiresorptive therapies. Teriparatide (human recombinant parathyroid hormone (PTH) 1–34, Forteo, Ely Lilly, Indianapolis, IN), which was the first in class to be approved in the United States, is the most widely used anabolic osteoporosis medicine and has shown significant benefit over traditional antiresorptive therapies. However, abaloparatide (synthetic parathyroid-related peptide (PTHrP), Tymlos, Radius Health, Waltham, MA), the second drug in this family, has recently become available for use. In this narrative review, we review the mechanism, effects, and benefits of abaloparatide compared to alternative treatments as well as discuss the current literature in regard to its effect on osteoporosis-related complications in the spine.

Is Teriparatide Beneficial to Spinal Fusion Surgery in the Older Patient?: A Narrative Review

Since FDA approval in 2002, teriparatide has gained popularity as an anabolic therapy for the treatment of osteoporosis. Animal studies have suggested a role for teriparatide in spine surgery. Several recent studies have demonstrated adjunctive use of teriparatide in osteoporotic patients undergoing spine fusions improves fusion rates, decreases time to union, and decreases osteoporosis-related complications such as proximal junctional kyphosis. On the basis of the available literature, we outline an algorithm for the use of teriparatide in spine surgery.

Anabolic agents: what is beyond osteoporosis?

Osteoporosis is a common skeletal disorder characterized by low bone mass, which leads to reduced bone strength and an increased risk of fractures. Anabolic agents have been shown to improve bone mass and decrease fracture risk in osteoporosis patients by directly stimulating osteoblasts to produce new bone. Currently, two anabolic agents are available in the USA: recombinantly produced teriparatide (TPTD), which is the fully active (1-34) amino active sequence of human parathyroid hormone (PTH), and abaloparatide (APTD), a synthetic analog of parathyroid hormone-related peptide (PTHrP). At present, both agents are approved only for treatment of patients with osteoporosis at high risk of fracture. Nonetheless, their anabolic properties have led to off-label application in additional settings which include spine fusion, osteonecrosis of the jaw, arthroplasty, and fracture healing. In this article, we summarize available scientific literature regarding the efficacy, effectiveness, and safety of TPTD in these off-label settings.

Limitations and complications of minimally invasive spinal surgery in adult deformity

Minimally invasive spine (MIS) surgery has rapidly progressed from simple short segment fusions to large adult deformity corrections, with radiographic and clinical outcomes as good as those of open surgery. Anterior longitudinal ligament release (ALLR) and anterior column realignment (ACR) have been key advancements in the ability to correct deformity using MIS techniques. However, patient selection and appropriate preoperative workup is critical to obtain good outcomes and for complication avoidance. Despite favorable outcomes in spinal deformity surgery, MIS techniques are limited in (I) pronounced cervical or thoracic deformity; (II) patients with prior fusion mass; and (III) severe sagittal imbalance necessitating Schwab 5 osteotomy or higher. Guidelines for proper patient selection are needed to guide MIS spine surgeons in choosing the right candidate.