The relationship between serum vitamin D levels and spinal fusion success: a quantitative analysis

Complete neurological recovery of spinal tuberculosis after spinal surgery and vitamin D supplementary: A case series

INTRODUCTION AND IMPORTANCE

Deaths from tuberculosis (TB) in Indonesia are nearly 200,000 per year and higher than those from COVID-19. The problems associated with spinal TB are vitamin D deficiency, neurological deficit, disruption of daily living activities and long-term anti-TB treatment (24 months). Vitamin D acts as an anti-inflammatory, maintains vascular health, and increases calcium levels.

CASE PRESENTATION

We reported 130 cases series spinal TB, neurological problems, vitamin D deficiencies; after surgery, anti-TB drugs and vitamin D adjuvant for 12 months. A TB diagnosis was confirmed by radiology, microbial and histopathology investigations.

CLINICAL DISCUSSION

After the treatment is shorter than standard conventional, patients had 100 % normal motor function, 3 % stiffness, 97.4 % fusion rate, 98.5 % normal vitamin D, minimal disability based on Oswestry Disability Index (ODI) scores, and normal function based on Japanese Orthopaedic Association (JOA) scores.

CONCLUSION

Vitamin D should be considered an adjuvant in spinal TB treatment, although further research is still needed to determine its efficacy and safety. Surgery and the administration of anti-TB drugs are still the standard procedures.

Bone Health Optimization in Adult Spinal Deformity Patients: A Narrative Review

Osteoporosis and low bone mineral density (BMD) pose significant challenges in adult spinal deformity surgery, increasing the risks of complications such as vertebral compression fractures, hardware failure, proximal junctional kyphosis/failure, and pseudoarthrosis. This narrative review examines the current evidence on bone health optimization strategies for spinal deformity patients. Preoperative screening and medical optimization are crucial, with vitamin D supplementation showing particular benefit. Among the pharmacologic agents, bisphosphonates demonstrate efficacy in improving fusion rates and reducing hardware-related complications, though the effects may be delayed. Teriparatide, a parathyroid hormone analog, shows promise in accelerating fusion and enhancing pedicle screw fixation. Newer anabolic agents like abaloparatide and romosozumab require further study but show potential. Romosozumab, in particular, has demonstrated significant improvements in lumbar spine BMD over a shorter duration compared to other treatments. Surgical techniques like cement augmentation and the use of larger interbody cages can mitigate the risks in osteoporotic patients. Overall, a multifaceted approach incorporating medical optimization, appropriate pharmacologic treatment, and tailored surgical techniques is recommended to improve outcomes in adult spinal deformity patients with compromised bone quality. Future research should focus on optimizing the treatment protocols, assessing the long-term outcomes of newer agents in the spine surgery population, and developing cost-effective strategies to improve access to these promising therapies.

Exercise improves load bearing bone structural properties in female secreted protein acidic and rich in cysteine (SPARC) null mice but not in males

Secreted protein acidic and rich in cysteine (SPARC) is the most abundant glycoprotein in bone and is thought to play a critical role in bone remodeling and homeostasis. However, the effect of SPARC in relation to gender and exercise on bone quality is not well understood. The purpose of this study was to quantify differences in the structural and biomechanical properties between calvarial and femoral bone from male and female wild-type (WT) and SPARC null (SPARC(-/-)) mice as well as the ability of exercise to rescue bone health. Male and female WT and transgenic SPARC(-/-) mice were given either a fixed or rotating running wheel for exercise. Bone structural, biomechanical, and morphological parameters were quantified using micro computed tomography, push out testing for the calvaria, three-point flexural testing for the femurs, histological and immunofluorescent staining. Similar reductions in structural and biomechanical strength were observed in both male and female SPARC(-/-) calvaria, most of which were not significantly affected by exercise. In femurs, SPARC(-/-) had a significant effect on structural parameters in both sexes, but was more pronounced in females with some properties being rescued with running. Interestingly, the effect of SPARC(-/-) on bone mineral density was only detected in female SPARC(-/-) mice, not males, and was subsequently rescued with exercise. This study emphasizes the differences between sexes in WT and SPARC(-/-) mice in regard to structural parameters and biomechanical properties. Research into gender differences can help inform and personalize treatment options to more accurately meet patient needs.

Do Adolescent Idiopathic Scoliosis Patients With Vitamin D Deficiency Have Worse Spine Fusion Outcomes?

BACKGROUND

Prior research has shown that patients with adolescent idiopathic scoliosis (AIS) have a higher prevalence of vitamin D deficiency compared with healthy peers. In adult orthopaedic populations, vitamin D deficiency has been shown to be a risk factor for higher reported pain and lower function. We investigated whether there was an association between vitamin D levels and AIS patient-reported outcomes, as measured by the Scoliosis Research Society (SRS-30) questionnaire.

METHODS

This was a single-center, cross-sectional study. Postoperative AIS patients were prospectively recruited during routine follow-up visits, 2 to 10 years after spine fusion. Vitamin D levels were measured by serum 25-hydroxyvitamin D (ng/mL). Patients were categorized based on vitamin D level: deficient (<20 ng/mL), insufficient (20 to 29 ng/mL), or sufficient (≥30 ng/mL). The correlation between vitamin D levels and SRS-30 scores was analyzed using multivariable analysis and pair-wise comparisons using Tukey method.

RESULTS

Eighty-seven AIS patients (83% female) were enrolled who presented at median 3 years (interquartile range: 2 to 5 y; range: 2 to 10 y) after spine fusion. Age at time of surgery was mean 15 (SD±2) years. Major coronal curves were a mean of 57 (SD±8) degrees preoperatively and 18 (SD±7) degrees postoperatively. It was found that 30 (34%) of patients were vitamin D sufficient, 33 (38%) were insufficient, and 24 (28%) were deficient. Although there was no correlation between vitamin D level and Pain, Mental Health, or Satisfaction domains ( P >0.05), vitamin D-deficient patients were found to be younger ( P <0.001) and had lower SRS-30 function ( P =0.002), Self-image ( P <0.001), and total scores ( P =0.003).

CONCLUSIONS

AIS patients with vitamin D deficiency (<20 ng/mL) are more likely to be younger age at time of surgery, and report lower Function, Self-image, and Total SRS-30 scores postoperatively. Further work is needed to determine whether vitamin D supplementation alters curve progression and patient outcomes.

LEVEL OF EVIDENCE

Level II-prognostic study.

The efficacy of oral vitamin D supplements on fusion outcome in patients receiving elective lumbar spinal fusion—a randomized control trial

Background

Previous studies have reported that vitamin D supplement could improve fracture healing, but evidence regarding the role of vitamin D supplements in spinal fusion was limited. Thus, this study aimed to evaluate the effectiveness of oral vitamin D supplements on fusion outcomes in patients undergoing lumbar spinal fusion.

Methods

This randomized, double-blind, parallel-designed, active-control trial included the patients who planned for elective lumbar spinal fusion. Eligible patients were randomly assigned to receive either daily vitamin D3 (cholecalciferol) 800 IU and daily calcium citrate 600 mg (experimental group) or only daily calcium citrate 600 mg (control group). All supplements were given from postoperative day 1 and lasted for 3 months. Primary outcome was postoperative 1-year fusion rate, and secondary outcomes included time to fusion, Oswestry Disability Index (ODI), and visual analogue scale (VAS) for pain.

Results

Among the included 34 patients (21 in the experimental group and 13 in the control group), baseline 25-hydroxyvitamin D (25[OHVitD) level was 26.7 (10.4) ng/ml. Preoperative prevalence of vitamin D deficiency and insufficiency were 23.5% and 47.1%, respectively. Postoperative 1-year fusion rate was not significantly different between the two groups (95.2% vs. 84.6%, P = 0.544). The experimental group had significantly shorter time to fusion (Kaplan–Meier estimated: 169 days vs. 185 days [interquartile range: 88–182 days vs. 176–324 days], log-rank test: P = 0.028), lower postoperative 6-month ODI (P < 0.001), and lower postoperative 6-month VAS (P < 0.001) than the control group. Time to fusion was significantly and negatively correlated with preoperative, postoperative 3-month, and 6-month 25(OH)VitD levels (all P < 0.01).

Conclusion

The patient with vitamin D supplements had shorter time to fusion, better spinal function and less pain after elective spinal fusion. Further research is warranted to identify the patients who can benefit the most from vitamin D supplements and the appropriate dose of vitamin D supplements.

Trial registration

ClinicalTrials.gov, NCT05023122. Registered 20 August 2021. Retrospectively registered, http://clinicaltrials.gov/ct2/show/NCT03793530.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-022-05948-9.

A Pre-clinical Standard Operating Procedure for Evaluating Orthobiologics in an In Vivo Rat Spinal Fusion Model

The rat animal model is a cost effective and reliable model used in spinal pre-clinical research. Complications from various surgical procedures in humans often arise that were based on these pre-clinical animal models. Therefore safe and efficacious pre-clinical animal models are needed to establish continuity into clinical trials. A Standard Operating Procedure (SOP) is a validated method that allows researchers to safely and carefully replicate previously successful surgical techniques. Thus, the aim of this study is to describe in detail the procedures involved in a common rat bilateral posterolateral intertransverse spinal fusion SOP used to test the efficacy and safety different orthobiologics using a collagen-soaked sponge as an orthobiologic carrier. Only two orthobiologics are currently FDA approved for spinal fusion surgery which include recombinant bone morphogenetic protein 2 (rhBMP-2), and I-FACTOR. While there are many additional orthobiologics currently being tested, one way to show their safety profile and gain FDA approval, is to use well established pre-clinical animal models. A preoperative, intraoperative, and postoperative surgical setup including specific anesthesia and euthanasia protocols are outlined. Furthermore, we describe different postoperative methods used to validate the spinal fusion SOP, which include μCT analysis, histopathology, biomechanical testing, and blood analysis. This SOP can help increase validity, transparency, efficacy, and reproducibly in future rat spinal fusion surgery procedures.

Concurrent Treatment with Vitamin K2 and D3 on Spine Fusion in Patients with Osteoporosis-Associated Lumbar Degenerative Disorders

STUDY DESIGN

A prospective and nonrandomized concurrent controlled trial.

OBJECTIVE

To address the early effects of concurrent treatment with vitamin K2 and vitamin D3 on fusion rates in patients who have undergone spinal surgery.

SUMMARY OF BACKGROUND DATA

Intervertebral pseudarthrosis has been reported after transforaminal lumbar interbody fusion (TLIF) or posterior lumbar interbody fusion (PLIF), especially in patients with osteopenia or osteoporosis. No study has assessed the early effects of concurrent treatment with vitamin K2 and vitamin D3 on fusion rates.

METHODS

Patients with osteopenia or osteoporosis who underwent TLIF or PLIF in our department were included. Patients in the VK2+VD3 group received vitamin K2, vitamin D3, and calcium treatment, whereas subjects in the control group only received calcium and vitamin D3. Spine fusion was evaluated by computed tomography. The Japanese Orthopedic Association Back Pain Evaluation Questionnaire (JOA-BPEQ) and visual analog scale (VAS) were used to assess the clinical and neurological symptoms. Bone mineral density (BMD) and bone metabolism markers were measured for osteoporotic evaluation.

RESULTS

Seventy-eight patients were included, and nine patients subsequently discontinued because of 2019-nCoV. At six months postoperatively, complete fusion rates were significantly higher in the VK2+VD3 group than that in the control group (91.18% vs 71.43%, P = 0.036). At six months postoperatively, BMD was increased in the VK2+VD3 group and was higher than that in the control group, although there was no significant difference. At three months postoperatively, a significant increase in procollagen type I amino terminal propeptide (91.81%) and a slight decrease in C-terminal end peptide (8.06%) were observed in the VK2+VD3 group. In both groups, the JOA-BPEQ and VAS scores were significantly improved after spine surgery.

CONCLUSION

Administration of vitamin K2 and vitamin D3 can increase lumbar interbody fusion rates, improve clinical symptoms, promote bone information, and avoid further decline in BMD within six months after TLIF or PLIF.Level of Evidence: 3.

Association of Pre-Operative Vitamin D Levels and Severity of Fracture among Orthopedic Trauma Patients in A Single, Tertiary-Level Hospital

Background/Purpose

The high prevalence of hypovitaminosis D among trauma patients have been related to risk of fractures, falls, non-union and poor operative outcomes. There is limited evidence that ties up Vitamin D levels with fracture severity. The objective of this study is to determine the association of pre-operative Vitamin D levels and fracture severity.

Methods

This was a retrospective, cross-sectional study of patients with extremity fractures classified according to the AO Trauma classification system with baseline pre-operative vitamin D levels. The association between vitamin D levels and fracture severity of surgically treated trauma patients were analyzed. Sub-group analysis was performed on patients without osteoporosis and those patients who suffered from low-energy trauma.

Results

Ninety-six (96) patients were included. Those with severe fractures (AO -C fractures, 31B1.3/B2.3 and 31A3) were associated with lower Vitamin D levels (µ  =  17.87 µg/mL) (p < 0.001). There was a strong, positive significant correlation ( rs (4)  =  .426, p  =  < 0.001) between hypovitaminosis D and increasing fracture severity. This significant association of hypovitaminosis D with worse fracture patterns remains in the patient sub-group without osteoporosis ( p  =  0.030), and in those who sustained low-mechanism injuries (­ p­ < 0.001).

Conclusion

We present initial evidence that low pre-operative Vitamin D level is associated with increasing fracture severity at the time of injury. Early detection, surveillance and management of low vitamin D levels can lead to drastic changes in the holistic approach to fracture prevention and treatment.

Osteoporosis and Spine Surgery: A Critical Analysis Review

Despite being part of the aging process, early and adequate management of osteoporosis mitigates adverse outcomes associated with low bone mineral density. Although the health-care burden of osteoporosis is on the rise, screening and management of osteoporosis are not yet an integral part of preoperative patient evaluation in spine surgery. Patients with osteoporosis should undergo multidisciplinary evaluation and management, including lifestyle modifications and initiation of multiple therapeutic modalities. Integrating osteoporosis in preoperative optimization and surgical planning for patients undergoing spine surgery has the potential to mitigate osteoporosis-related postoperative complications.

Recombinant Human Bone Morphogenetic Protein-2 Improves Spine Fusion in a Vitamin D-Deficient Rat Model

BACKGROUND

The effects of vitamin D deficiency on spinal fusion are not well studied, nor are approaches to overcoming deficiency-related detrimental effects. The purpose of this study was to (1) evaluate the effects of vitamin D deficiency on spine fusion in a rat model, and (2) determine whether recombinant human bone morphogenetic protein-2 (rhBMP-2) can improve outcomes in deficient rats.

METHODS

Sprague-Dawley rats were assigned to a vitamin D group: vitamin D sufficient (14), vitamin D deficient (16), vitamin D postoperative rescue (15). Posterolateral fusion was performed at L3-4 and L5-6, with one level receiving rhBMP-2 and the other allograft. Following 6 weeks, the spines were harvested for micro-computed tomography (micro-CT) and histological analyses. Fusion was assessed via manual palpation and micro-CT assessment. Micro-CT images were analyzed for bone microarchitecture in intact L5 vertebral bodies and within fused bone masses treated with rhBMP-2.

RESULTS

There were no significant effects of vitamin D status on fusion assessments. However, the microarchitecture of native bone in the intact L5 vertebral bodies of vitamin D-sufficient rats showed significantly greater trabecular thickness (P < .001) and bone volume fraction (P < .001), with decreased trabecular spacing (P < .001), than that of vitamin D-deficient rats. Fusion masses of rhBMP-2 levels also showed significant effects of vitamin D supplementation on both bone volume fraction and trabecular thickness. Histological analysis confirmed that robust bone formation was observed in rhBMP-2-treated fusions, but not in fusion levels treated with allograft.

CONCLUSIONS

Overall, vitamin D deficiency decreased trabecular bone microarchitecture, and treatment with rhBMP-2 improved outcomes across all vitamin D groups.

CLINICAL RELEVANCE

Given the prevalence of vitamin D deficiency in spine surgery patients, vitamin D supplementation may be a cost-effective method for reducing the risk of pseudoarthrosis.

Preoperative vitamin D status and its effects on short-term clinical outcomes in lumbar spine surgery

BACKGROUND

Many studies have found that vitamin D deficiency has a high incidence rate worldwide, but we found few studies on the role of vitamin D in spinal degenerative diseases. We investigated the determinants of preoperative vitamin D deficiency and its effects on postoperative outcomes among patients undergoing elective lumbar spine surgery.

METHODS

360 patients treated from July 2017 to July 2018 were retrospectively identified for inclusion. The patients' fasting serum levels of 25(OH)D, N-terminal midfragment of osteocalcin (N-MID), and β typeⅠcollagen carboxyl terminal peptide (β-CTX) were measured by electrochemiluminescence before the operation. The visual analogue scale (VAS), Japanese Orthopaedic Association (JOA) and Oswestry Disability Index scores (ODI) were used to evaluate the clinical outcomes. Standard demographic data and all perioperative complications occurring within 3 months follow-up after operation were recorded.

RESULTS

The mean serum level of 25(OH)D was 20.81 ± 8.55 ng/mL, the rates of deficiency (<20 ng/ml) was 53.6%. The abnormal proportion of N-MID and β-CTX were 8.61% and 34.44%, bone turnover markers serum level was higher in older age groups (p < 0.05). Female sex (p < 0.001), a high body mass index (BMI) (p = 0.012), lack of vitamin D supplementation (p = 0.018), smoking (p = 0.033), moderate (p < 0.001) to severe pain (p = 0.005) were significant predictors of vitamin D deficiency after the multivariate analysis. The VAS, JOA and ODI scores showed significantly better outcomes compared to deficient group at post-operative and final follow-up (p < 0.05).

CONCLUSION

Vitamin D deficiency was common in patients undergoing elective lumbar spine surgery. Female sex, high BMI, lack of vitamin D supplementation, smoking and moderate to severe pain were risk factors for vitamin D deficiency. Moreover, preoperative hypovitaminosis D (<20 ng/ml) was correlated with worse surgical outcomes in short-term.

A Review of Vitamin D in Spinal Surgery: Deficiency Screening, Treatment, and Outcomes

In this review, we discuss the demonstrated value of vitamin D in bone maintenance, fracture resistance, spinal health, and spine surgery outcomes. Despite this, the effect of vitamin D levels in spine surgery has not been well described. Through this review of literature, several conclusions were drawn. First, despite the fact that a high number of spine surgery patients are vitamin D deficient, screening is not commonly performed. Second, adequate vitamin D levels will not be achieved in a majority of these patients without supplementation. Last, inadequate vitamin D levels may increase the risk of pseudarthrosis. Given these findings, we suggest that many patients undergoing spinal surgery could be treated with vitamin D supplementation prior to surgery without the need for confirmatory testing for vitamin D deficiency. This is a more cost-effective method than screening all patients. However, future randomized trials and cost-effectiveness analyses are needed to determine the ultimate effects of vitamin D supplementation on clinical morbidity and surgical outcomes.

Electrospun, synthetic bone void filler promotes human MSC function and BMP-2 mediated spinal fusion

INTRODUCTION

Synthetic bone grafts are often used to achieve a well-consolidated fusion mass in spinal fusion procedures. These bone grafts function as scaffolds, and ideally support cell function and facilitate protein binding.

OBJECTIVE

The aim was to characterize an electrospun, synthetic bone void filler (Reb) for its bone morphogenetic protein (BMP)-2 release properties and support of human mesenchymal stem cell (hMSC) function in vitro, and its efficacy in promoting BMP-2-/bone marrow aspirate-(BMA)-mediated posterolateral spinal fusion (PLF) in vivo.

METHODS

BMP-2 release kinetics from Reb versus standard absorbable collagen sponge (ACS) was determined. hMSC adhesion and proliferation on Reb was tested using cell counting, fluorescence microscopy and MTS. Cell osteogenic differentiation was quantified via cellular alkaline phosphatase (ALP) activity. For in vivo analysis, 18 Lewis rats were treated during PLF surgery with the following groups: (I) Reb + BMA, (II) Reb + BMA + BMP-2 and (III) BMA. A safe, minimally effective dose of BMP-2 was used. Fusion consolidation was followed for 3 months using radiography and micro-CT. After sacrifice, fusion rate and biomechanical stiffness was determined using manual palpation, biomechanical tests and histology.

RESULTS

In vitro, BMP-2 release kinetics were similar between Reb versus ACS. MSC proliferation and differentiation were increased in the presence of Reb. At 3 months post-surgery, fusion rates were 29% (group I), 100% (group II), and 0% (group III). Biomechanical stiffness was higher in group II versus I. Micro-CT showed an increased bone volume and connectivity density in group II. Trabecular thickness was increased in group I versus II. H&E staining showed newly formed bone in group II only.

CONCLUSIONS

Reb possesses a high protein binding affinity and promotes hMSC function. Combination with BMA and minimal dose BMP-2 allowed for 100% bone fusion in vivo. This data suggests that a minimally effective dose of BMP-2 can be used when combined with Reb.

The effect of insulin dependent diabetes on bone metabolism and growth after spinal fusion

STUDY DESIGN

Experimental animal model.

OBJECTIVE

The purpose of this study was to evaluate the hypothesis that insulin dependent diabetes mellitus (IDDM) will inhibit the formation of a solid bony union after spinal fusion surgery via an alteration of the microenvironment at the fusion site in a rat model.

SUMMARY OF BACKGROUND DATA

Previous studies report diabetes mellitus (DM) and specifically IDDM as a risk factor for complications and poor surgical outcomes following spinal fusion.

METHODS

Twenty control and 22 diabetic rats were obtained at 5 weeks of age. At 20 weeks of age, all animals underwent posterolateral lumbar fusion surgery using a tailbone autograft with diabetic rats receiving an implantable time release insulin pellet. A subset of rats was sacrificed 1-week postsurgery for growth factor (PDGF, IGF-I, TGF-β, and VEGF) and proinflammatory cytokine ELISA analysis. All other rats were sacrificed 3-months postsurgery for fusion evaluation via manual palpation and micro CT. Glycated hemoglobin (HbA1c) was measured at surgery and sacrifice on all animals.

RESULTS

Compared with healthy rats undergoing spinal fusion, rats with IDDM demonstrated a significant reduction in manual palpation fusion rates (16.7% vs. 43%, p<.05). Average bone mineral density, bone volume, and bone volume fraction were also significantly reduced and negatively correlated to blood glucose levels. IL-1B, IL-5, IL-10, TNF-α, and KC/GRO were significantly elevated in fusion beds of IDDM rats.

CONCLUSIONS

This study demonstrates that rats with IDDM demonstrate a reduced rate and quality of spinal fusion with increased local levels of inflammatory cytokines. Targeted modalities are required to improve bone healing in this growing, high-risk population.

CLINICAL SIGNIFICANCE

This is the first translational animal model of IDDM to evaluate the rate and quality of spinal fusion while controlling for other surgical and patient-related risk factors. Our findings demonstrate the complex nature by which IDDM impairs bone healing and highlight the need for additional basic science research to further elucidate this mechanism in order to develop more effective therapeutic interventions.

Vitamin D in the Foot and Ankle: A Review of the Literature

BACKGROUND

Vitamin D is an essential vitamin that targets several tissues and organs and plays an important role in calcium homeostasis. Vitamin D deficiency is common, particularly at higher latitudes, where there is reduced exposure to ultraviolet B radiation. We reviewed the role of vitamin D and its deficiency in foot and ankle pathology.

METHODS

The effects of vitamin D deficiency have been extensively studied, but only a small portion of the literature has focused on the foot and ankle. Most evidence regarding the foot and ankle consists of retrospective studies, which cannot determine whether vitamin D deficiency is, in fact, the cause of the pathologies being investigated.

RESULTS

The available evidence suggests that insufficient vitamin D levels may result in an increased incidence of foot and ankle fractures. The effects of vitamin D deficiency on fracture healing, bone marrow edema syndrome, osteochondral lesions of the talus, strength around the foot and ankle, tendon disorders, elective foot and ankle surgery, and other foot and ankle conditions are less clear.

CONCLUSIONS

Based on the available evidence, we cannot recommend routine testing or supplementation of vitamin D in patients with foot and ankle pathology. However, supplementation is cheap, safe, and may be of benefit in patients at high risk for deficiency. When vitamin D is supplemented, the evidence suggests that calcium should be co-supplemented. Further high-quality research is needed into the effect of vitamin D in the foot and ankle. Cost-benefit analyses of routine testing and supplementation of vitamin D for foot and ankle pathology are also required.

The effects of varenicline on lumbar spinal fusion in a rat model

BACKGROUND CONTEXT

Smoking is detrimental to obtaining a solid spinal fusion mass with previous studies demonstrating its association with pseudoarthrosis in patients undergoing spinal fusion. Varenicline is a pharmacologic adjunct used in smoking cessation which acts as a partial agonist of the same nicotinic receptors activated during tobacco use. However, no clinical or basic science studies to date have characterized if varenicline has negative effects on spinal fusion and bone healing by itself.

PURPOSE

Our study's aim was to elucidate whether varenicline affects the frequency or quality of posterolateral spinal fusion in a rodent model at an endpoint of 12 weeks.

STUDY DESIGN

Randomized control trial.

PATIENT SAMPLE

Fourteen male Lewis rats randomly separated into two experimental groups.

OUTCOME MEASURES

Manual palpation of fusion segment, radiography, μCT imaging, and four-point bend.

METHODS

Fourteen male Lewis rats were randomly separated into two experimental groups undergoing L4-L5 posterior spinal fusion procedure followed by daily subcutaneous injections of human dose varenicline or saline (control) for 12 weeks postsurgery. Spine samples were explanted, and fusion was determined via manual palpation of segments by two independent observers. High-resolution radiographs were obtained to evaluate bridging fusion mass. μCT imaging was performed to characterize fusion mass and consolidation. Lumbar spinal fusion units were tested in four-point bending to evaluate stiffness and peak load. Study funding sources include $5000 OREF Grant. There were no applicable financial relationships or conflicts of interest.

RESULTS

At 3 months postsurgery, 12 out of 14 rats demonstrated lumbar spine fusion (86% fused) with no difference in fusion frequency between the varenicline and control groups as detected by manual palpation. High-resolution radiography revealed six out of seven rats (86%) having complete fusion in both groups. μCT showed no significant difference in bone mineral density or bone fraction volume between groups in the region of interest. Biomechanical testing demonstrated no significant different in the average stiffness or peak loads at the fusion site of the varenicline and control groups.

CONCLUSION

Based on the results of our rat study, there is no indication that varenicline itself has a detrimental effect on the frequency and quality of spinal fusion.

Effect of local zoledronic acid administration in a rat model of posterolateral spinal fusion

Study design

Randomized animal model study.

Purpose

Posterolateral spinal fusion represents a common surgical procedure in the United States. The effect of bisphosphonate administration in these patients is poorly understood. The purpose of this study is to determine whether local administration of bisphosphonate by soaking bone autograft would affect the apparent bone density or structural properties of the fusion mass in a rat model of posterolateral spinal fusion.

Methods

36 Spring Dawley rats underwent L4-5 posterolateral spinal fusion with bone autograft. These rats were divided into three groups, two experimental groups and one control group. Each of the experimental groups underwent spinal fusion with morselized vertebral cortical and cancellous autograft soaked in zoledronic acid solution; one group 20 mcg/mL, another 200 mcg/mL. The control group underwent L4-5 spinal fusion with cancellous allograft soaked with saline. At 8 weeks, the rats were euthanized for analysis. Evaluations consisted of micro-CT scanning, four-point bending biomechanical testing, histology, and radiographs.

Results

Both of the experimental groups showed statistically significant increase in apparent bone density and bone volume fraction at the fusion mass. Biomechanical measures revealed a trend for improvement in the experimental groups, but these did not reach statistical significance.

Conclusions

This data suggest that locally administered bisphosphonate medications result in increased apparent bone density and bone volume fraction at the fusion mass in posterolateral spinal fusion, and that there appear to be no deleterious consequences with regards to the stiffness or maximum load to failure of the fusion mass under flexion bending evaluation.

The impact of type 2 diabetes on bone metabolism and growth after spinal fusion

BACKGROUND CONTEXT

Some clinical reports suggest diabetes may have a negative effect on spinal fusion outcomes, although no conclusive experimental research has been conducted to investigate the causality, impact, and inherent risks of this growing patient population.

PURPOSE

To analyze the hypothesis that type 2 diabetes (T2DM) inhibits the formation of a solid bony union after spinal fusion surgery by altering the local microenvironment at the fusion site through a reduction in growth factors critical for bone formation.

STUDY DESIGN/SETTING

In vivo rodent model of type 2 diabetes.

METHODS

Twenty control (Sprague Dawley, SD) and 30 diabetic (Zucker Diabetic Sprague Dawley, ZDSD) rats underwent posterolateral and laminar fusion surgery using a tailbone autograft implanted onto the L4/L5 transverse processes. A subset of animals was sacrificed 1-week postsurgery for growth factor analysis. Remaining rats were sacrificed 3-month postsurgery for fusion evaluation via manual palpation, micro-CT, and histology.

RESULTS

There was no significant difference in the manual palpation fusion rate between ZDSD rats and SD control rats. Growth factor assay of fusion site explants at early sacrifice demonstrated PDGF was upregulated in the ZDSD rats. TGFB, IGF, and VEGF were not statistically different between groups. Bone mineral density as determined by micro-CT was significantly lower in ZDSD rats compared to SD controls and was a significant function of HbA1c.

CONCLUSIONS

Data generated in this in vivo rat model of T2DM demonstrate that the metabolic dysregulation associated with the diabetic condition negatively impacts the quality and density of the formed fusion mass. Increased measures of diabetic status, as determined by blood glucose and HbA1c, were correlated with decreased quality of formed fusion, highlighting the importance of diabetic status monitoring and regulation to bone health, particularly during bone healing.

CLINICAL RELEVANCE

T2DM rats demonstrated increased rates of infection, metabolic dysregulation, and a reduction in spinal fusion consolidation. Clinicians should consider these negative effects during preoperative care and treatment of this growing patient population.

Vitamin D levels in 577 consecutive elective foot & ankle surgery patients

BACKGROUND

Vitamin D deficiency is a global concern impacting upon large communities and certain disease populations. It can adversely affect the outcome of orthopaedic operations. We aimed to perform an audit of the Vitamin D status of patients in two centres in the United Kingdom undergoing elective foot and ankle surgery.

METHODS

Serum 25-hydroxyvitamin-D (vitamin D) levels were obtained prospectively in 577 consecutive elective patients undergoing elective foot and ankle surgery between October 2014 and March 2017 (29 months). Variables including age, gender, ethnicity, location, season, month and procedure type were recorded.

RESULTS

577 patients were included over the study period. 62.0% were female. Mean age was 53.2 (median 54.5, range 16.7-86.6). 300 patients were treated in Northampton and 277 in Leicester. The serum 25-hydroxyvitamin-D levels for the patient group were normally distributed. The mean was 52.3nmol/L (SD 28.0; range 7.5-175) and the median 47.5nmol/L. 21.7% were grossly deficient, 31.9% deficient, 28.9% insufficient and 17.5% within normal range. Age, gender and procedure type did not statistically affect vitamin D levels (p=0.5, t-test). Ethnicity, location and Winter season did affect Vitamin D levels (p<0.05). August was the most significant month with levels significantly higher than January, February, March, April, June, November and December (p<0.05, one-way ANOVA).

CONCLUSIONS

Only 1 in 5.7 patients had a normal Vitamin D level and 1 in 4.6 were grossly deficient. Ethnicity and patient location significantly affected Vitamin D results. Summer months were noted to demonstrate significantly the highest levels and August the highest. We did not find that age or gender affected Vitamin D levels in our cohort.

The Preoperative Supplementation With Vitamin D Attenuated Pain Intensity and Reduced the Level of Pro-inflammatory Markers in Patients After Posterior Lumbar Interbody Fusion

The aim of this experimental study was to assess whether 5 weeks of preoperative supplementation with vitamin D affects the intensity of pain and the level of inflammatory markers in patients undergoing posterior lumbar interbody fusion (PLIF) followed by rehabilitation. 42 patients were divided, by double-blind randomization, into two groups: supplemented (SUPL) vitamin D (3200 IU dose of vitamin D/day for 5 weeks) and placebo group (PL) treated with vegetable oil. The 10-week program of early rehabilitation (3 times a week) was initiated 4 weeks following PLIF. Measurements of serum 25(OH)D3 and CRP, IL-6, TNF-α, and IL-10 were performed. Pain intensity was measured using VAS. After supplementation with vitamin D serum, the concentration of 25(OH)D3 significantly increased in the SUPL group (∗ p < 0.005) and was significantly higher as compared to the PL group (∗ p < 0.001). A significant reduction in pain intensity was observed 4 weeks after surgery and after rehabilitation in both groups. In the SUPL group, serum CRP and IL-6 concentration significantly decreased after rehabilitation, compared with the postsurgical level (a p < 0.04). The level of TNF-α was significantly lower after rehabilitation only in the supplemented group (∗ p < 0.02). There were no significant changes in the IL-10 level in both groups during the study. Our data indicate that supplementation with vitamin D may reduce systemic inflammation and when combined with surgery and early postsurgical rehabilitation, it may decrease the intensity of pain in LBP patients undergoing PLIF. Data indicate that LBP patients undergoing spine surgery should use vitamin D perioperatively as a supplement.

Effect of modulating dietary vitamin D on the general bone health of rats during posterolateral spinal fusion

Vitamin D plays a significant role in musculoskeletal health by regulating calcium, phosphate, and promoting new bone mineralization. The purpose of this study was to understand the effect of dietary vitamin D on general bone health during peri-operative bone healing via an in vivo dosing study of vitamin D in a rat posterolateral fusion model using autograft. Vitamin D Deficient (DD), vitamin D Insufficient (ID), Control vitamin D (CD), and Hyper-vitamin D (HD) groups were studied. Increasing dietary vitamin D improved quantitative measures of femoral geometry, including femoral strength, stiffness, and density. Femoral biomechanics, cortical thickness, moment of inertia, cross-sectional area, and measures from bone ashing were all greater in the HD group versus the CD. This suggests that additional dietary vitamin D above normal levels during spinal fusion may lead to improvement in bone health. Serum vitamin D levels were also observed to decrease during fusion healing. These results demonstrate that dietary vitamin D improves general bone health in the femur of a rat model during posterolateral spinal fusion. This suggests a role for further clinical evaluation of vitamin D dietary intake during the peri-operative period, with the possibility of avoiding adverse consequences to general bone health. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1435-1443, 2018.

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.

Distraction arthrodesis of the sacroiliac joint: 2-year results of a descriptive prospective multi-center cohort study in 171 patients

PURPOSE

The aim of the given study was to evaluate the long-term outcomes of patients undergoing sacroiliac joint (SIJ) distraction arthrodesis to treat SIJ-related pain.

METHODS

Descriptive prospective multi-center cohort study involving 20 hospitals in Germany. Between January 2011 and June 2012, 171 patients with chronic SIJ pain underwent indirect arthrodesis of the SIJ using a distraction implant. The patients were questioned prior to surgery, 6-weeks, and 3-, 6-, 12- and 24-months postoperatively. Overall patient satisfaction was surveyed along with pain medication intake, the Million Visual Analogue Scale (MVAS), Oswestry Disability Index (ODI), Short-form McGill Pain Questionnaire (SF-MPQ), 12-Item Short-Form Health Survey (SF-12), Visual Analogue Scale (VAS) and a pain drawing. Bony fusion of the SIJ was evaluated using X-ray and computed tomography (CT).

RESULTS

A majority of patients (73%) reported to feel better or much better 24 months post-surgery, 49% of the patients reduced their pain medication intake. The MVAS dropped from 63 to 36%, the ODI improved from 51 to 33%, the SF-MPQ decreased from 50 to 31%, the SF-12 physical component summary rose from 22 to 41%, the mental component summary increased from 40 to 55%, and pain as measured by the VAS decreased from 74 to 37 points (all comparisons p < 0.001). In the follow-up CT scans 31% of the patients showed SIJ fusion.

CONCLUSIONS

SIJ distraction arthrodesis has shown satisfactory outcomes in patients with SIJ-related pain for all scores reported in the surveys, accompanied by increased functionality.

Do 25-Hydroxyvitamin D Levels Correlate With Fracture Complications?

OBJECTIVES

To determine the relationship between serum 25-hydroxyvitamin D [25(OH)D] levels and the likelihood of postoperative complications and fracture reoperation rate in orthopaedic trauma patients receiving vitamin D and calcium supplementation.

DESIGN

Retrospective case series.

SETTING

Level I trauma center, Midwestern United States.

PATIENTS

All orthopaedic trauma patients-18 years or older-over a 20-month period were included with available initial and repeat 25(OH)D serum levels. In total, 201 patients met inclusion criteria.

INTERVENTION

All patients received 1000 IU of vitamin D3 and 1500 mg of calcium daily. Vitamin D deficient and insufficient patients also received 50,000 IU of ergocalciferol (vitamin D2) weekly until 25(OH)D levels normalized or fractures healed.

MAIN OUTCOME MEASUREMENTS

fracture complications and 25(OH)D levels.

RESULTS

Fifteen patients experienced postoperative healing complications. There was no significant difference between initial (P = 0.92) or repeat (P = 0.91) 25(OH)D levels between patients with and without fracture healing complications. Twenty-eight patients required repeat orthopaedic surgery. There was no significant difference between initial (P = 0.62) or repeat (P = 0.18) 25(OH)D levels between patients who did or did not require repeat orthopaedic surgery. There was no significant difference between initial (P = 0.66) or repeat (P = 0.89) 25(OH)D levels between patients who did or did not require nonorthopaedic surgery.

CONCLUSIONS

Serum 25(OH)D levels did not significantly affect the likelihood of fracture healing complications requiring surgery or any nonorthopaedic injury-related surgery.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Association Between Vitamin D Deficiency and Outcomes Following Spinal Fusion Surgery: A Systematic Review

BACKGROUND

Vitamin D deficiency is a relatively common occurrence in patients presenting for spinal surgery; however, whether this abnormality has any effect on spinal fusion outcomes remains unclear. We performed a systematic review of the available literature relevant to the association between vitamin D deficiency and spinal fusion outcomes.

METHODS

We conducted a systematic and critical review of recent literature following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The following databases were searched: MEDLINE/PubMed, Google Scholar, Cochrane, Web of Science, and Scopus. Key search terms were "vitamin D," "spinal surgery outcomes," "spinal fusion," and "pseudarthrosis." Papers included in the review were original research articles in peer-reviewed journals. The articles were thoroughly examined and compared on the basis of study design, outcomes, and results.

RESULTS

A total of 5 studies were included in the qualitative analysis. In these studies, patients presenting with vitamin D deficiency achieved lower fusion rates and suffered higher rates of recurrent-persistent low back pain compared with patients with normal vitamin D levels. Studies examining the effect of postoperative vitamin D supplementation in deficient patients reported significant improvements in low back pain intensity, patient-reported outcomes scores, and fusion rates compared with baseline as well as with control groups.

CONCLUSIONS

The literature suggests that patients presenting for spinal fusion may benefit from correction of vitamin D deficiency to maximize the chance of a successful arthrodesis and to achieve optimal surgical outcomes. Future prospective studies are needed to determine whether routine preoperative treatment of this metabolic derangement is warranted.

Medical Management of Osteoporosis for Elective Spine Surgery

Over 50 million Americans have low bone mass. Poor bone quality is known to complicate spinal fusion surgery, which relies on strong bony purchase to be effective. Unfortunately, many spine surgeons do not perform routine workups for either osteoporosis or osteomalacia. Effective screening and risk factor assessment can allow for appropriate medical management of osteoporosis in the perioperative setting, improving outcomes. Medical management can be grouped into several different categories: vitamins and minerals, bisphosphonates, recombinant parathyroid hormone, estrogen replacement or modification, inhibitors of receptor activator of nuclear factor κ-B ligand (RANKL), and calcitonin. Calcium and vitamin D supplements are the least expensive to prescribe, with minimal side effects and promising animal studies, and thus should be provided to most osteoporotic patients. Recombinant parathyroid hormone can also be considered, as clinical studies have demonstrated impressive results in spine fusion patients. Bisphosphonates, estrogen therapy or selective estrogen receptor modulators, and calcitonin should all be avoided in this patient population given unproven benefit and potentially harmful side-effect profiles. Denosumab is potentially an option, but may not be first line given the general lack of supporting data for its use in perioperative management of spine surgery patients.