Evaluation of bone mineral density after instrumented lumbar fusion with computed tomography.

BACKGROUND CONTEXT: Computed tomography (CT) measurement of Hounsfield Units (HU) has been described as a tool for assessing BMD. For surgeons considering a revision lumbar fusion, knowledge of the BMD of the UIV is of value for surgical planning. However, the presence of metal artifact from instrumentation presents a potential confounder, and prior studies have not validated measurements of HU in this setting. PURPOSE: To determine if HU can be measured reliably at the supra-adjacent and upper instrumented levels of a lumbar fusion. STUDY DESIGN: Retrospective observational cohort PATIENT SAMPLE: Consecutive series of patients who had lumbar CT scans after an instrumented posterior lumbar fusion. OUTCOME MEASURES: Hounsfield Units at the upper instrumented vertebra and levels proximal. METHODS: We analysed pre- and postoperative CT scans of 50 patients who underwent L2 and distal instrumented lumbar fusion whose scans were no greater than 1 year apart, obtaining HU measurements of analogous axial cuts at the upper instrumented level (immediately caudal to the halo of the pedicle screw), as well as additional control levels above the construct. RESULTS: The HU at the pre-and postoperative UIV exhibited a strong correlation (r=0.917, p<.001), as did one (r=0.887, p<.001) and two (r=0.853, p<.001) levels above the UIV. There were significant but predictable reductions in the postoperative HU compared to preoperative at one (-9.0±26.2) and two (-12.2±30.2) levels above the UIV, as well as T12 (-13.9±42.2). There was no significant difference in HU at the UIV (4.6±34.1). CONCLUSIONS: Postoperative HU at the UIV was strongly correlated with and not significantly different from the preoperative HU. Although the HU in the vertebrae proximal to the UIV were slightly lower postoperatively, this change was predictable using a correction factor.

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.

Opportunistic Computed Tomography and Spine Surgery: A Narrative Review.

STUDY DESIGN: Narrative review. OBJECTIVE: This article seeks to provide a narrative review regarding the ability of opportunistic information available from computed tomography (CT) scans to guide decisions in spine surgery related to patient bone quality. METHODS: A review of the literature (limited to human and English language) was performed via PubMed and Google Scholar using the search terms; "osteoporosis" AND "opportunistic" AND "computed tomography" AND "spine surgery." The titles and then abstracts of all identified citations were reviewed for inclusion by 2 of the authors (MS, BAF). Relevant articles were then studied in full text. RESULTS: A review of the literature found 25 articles that were selected for inclusion in this narrative review. These articles were broadly divided into 4 subcategories: (1) opportunistic CT (oCT) and osteoporosis detection, (2) oCT data and the quality of screw fixation, (3) utilization of Hounsfield units to assess clinical and/or radiographic outcomes following spine fusion, and (4) virtual stress testing in spine surgery. CONCLUSION: The literature on oCT, as well as associated virtual stress-testing techniques, demonstrate the potential to enhance spine surgery outcomes by preoperatively identifying at-risk patients in need of bone health optimization and informing best techniques for performing spinal fusion surgery on patients with diminished bone quality. While our narrative summary of the limited literature to date suggests a promising future for oCT data, significant additional research and/or radiographic workflow standardization is needed to validate these methods for clinical use.

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.

Osteoporosis-related Vertebral Fragility Fractures: A Review and Analysis of the American Orthopaedic Association's Own the Bone Database.

STUDY DESIGN: Retrospective cohort study of the Own the Bone database which is a fracture liaison service designed to improve recognition and treatment of osteoporosis. OBJECTIVE: To use the Own the Bone (OTB) database to 1) examine the specific demographics of patients presenting with a low-energy clinical vertebral fracture (VFX) and 2) compare demographic and fracture-specific risk factors between patients with clinical VFX versus patients with nonvertebral low-energy fracture (NVFX). SUMMARY OF BACKGROUND DATA: Large database studies have described risk factors for developing VFX. It is well described that a history of previous VFX portends an increased risk of future VFX. Few studies have reported cohorts from a fracture liaison service such as the OTB initiative. METHODS: 35,039 unique cases of fragility fracture occurred between 2009 and 2016 and were included in analysis. VFX accounted for 3395 (9.9%) of the presenting fractures at OTB enrollment. The demographics, lifestyle factors, medication use, and fracture-specific data for patients in the OTB registry with vertebral fractures were summarized and then statistically compared to those with nonvertebral fragility fractures. RESULTS: The majority of VFX patients were Caucasian, postmenopausal women (74.4%). There was an increased likelihood of presenting with a vertebral fracture in patients who sustained a previous VFX after the age of 50, while patients who sustained a prior nonvertebral fracture (NVFX) were more likely to present with a subsequent NVFX. After controlling for patients with a history of fracture after the age of 50, VFX patients (vs. NVFX) were more likely to be age 70-79, class 1 obesity, with a history of taking anti-osteoporotic prescription medications. CONCLUSIONS: Multiple factors were associated with a significantly increased risk of VFX compared with NVFX. Understanding the risk factors unique to fragility VFX is a critical component for targeting "at-risk" patients and preventing future osteoporosis-related fractures and their consequences. LEVEL OF EVIDENCE: 4.

Reverse shoulder arthroplasty for patients with glenohumeral osteoarthritis secondary to glenoid dysplasia.

The purpose is to report the clinical and radiographic outcomes, complications and reoperations of reverse shoulder arthroplasty (RSA) for glenoid dysplasia. All patients who had undergone RSA for osteoarthritis secondary to underlying glenoid dysplasia were retrospectively identified. The study included twelve shoulders (11 patients), with a mean (SD) patient age of 62.2 (13.2) years and median (range) clinical follow-up of 28 (24-34) months. RSA resulted in substantial improvements in pain and function. At most recent follow-up, there was a significant improvement in forward flexion range of motion (ROM), a non-significant improvement in internal rotation ROM, and no changes in external rotation ROM. The mean (SD) SST and ASES scores were 7.8 (3.7) and 73.5 (20.4), respectively. There were no reoperations or radiographic loosening. The results were excellent in 1 case, satisfactory in 8, and unsatisfactory in 3. RSA provides acceptable function and good pain relief, though patients should be advised that shoulder rotation may be somewhat limited.

Outcomes and Direct Costs of Needle Aponeurotomy, Collagenase Injection, and Fasciectomy in the Treatment of Dupuytren Contracture.

PURPOSE: The aims of our study were to evaluate the rates and predictors of reinterventions and direct costs of 3 common treatments of Dupuytren contractures-needle aponeurotomy, collagenase injection, and surgical fasciectomy. METHODS: A retrospective review identified 848 interventions for Dupuytren contracture in 350 patients treated by a single surgeon from 2005 to 2016. The treatments included needle aponeurotomy (NA) (n = 444), collagenase injection (n = 272), and open fasciectomy (n = 132). We collected information on demographics, contracture details, and comorbidities. Outcomes included reintervention rates, time to reintervention, and direct cost of treatments. Standardized costs were calculated by applying 2017 Medicare reimbursement to professional services and cost-to-charge ratios to hospital charges. RESULTS: Demographics were similar among the 3 treatment groups. The fifth finger was the most commonly affected digit including 43% of the NA, 60% of the collagenase, and 45% of the fasciectomy groups. The 2-year rates of reintervention following NA, collagenase, and fasciectomy were 24%, 41%, and 4%, respectively, and the 5-year rates were 61%, 55%, and 4%, respectively. Younger age and severity of preintervention proximal interphalangeal (PIP) joint contracture were predictive of reintervention in the NA and collagenase groups. The standardized direct costs for NA, collagenase, and fasciectomy were $624, $4,189, and $5,291, respectively. Including all reinterventions, the cumulative costs per digit following NA, collagenase, and surgery at 5 years were $1,540, $5,952, and $5,507, respectively. CONCLUSIONS: Treatment with collagenase resulted in the highest rate of reintervention at 2 years, comparable reintervention rates to NA at 5 years, and the highest cumulative costs. The NA was the least expensive and resulted in longer duration before reintervention compared with collagenase. More severe PIP joint contractures and younger age at time of initial intervention were predictive of reintervention after collagenase and NA. Fasciectomy has a high initial cost but the lowest reintervention rate. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

A Review and Clinical Perspective of the Impact of Osteoporosis on the Spine.

INTRODUCTION: Osteopenia and osteoporosis are common conditions in the United States. The health consequences of low bone density can be dire, from poor surgical outcomes to increased mortality rates following a fracture. SIGNIFICANCE: This article highlights the impact low bone density has on spine health in terms of vertebral fragility fractures and its adverse effects on elective spine surgery. It also reviews the clinical importance of bone health assessment and optimization. RESULTS: Vertebral fractures are the most common fragility fractures with significant consequences related to patient morbidity and mortality. Additionally, a vertebral fracture is the best predictor of a subsequent fracture. These fractures constitute sentinel events in osteoporosis that require further evaluation and treatment of the patient's underlying bone disease. In addition to fractures, osteopenia and osteoporosis have deleterious effects on elective spine surgery from screw pullout to fusion rates. Adequate evaluation and treatment of a patient's underlying bone disease in these situations have been shown to improve patient outcomes. CONCLUSION: With an increased understanding of the prevalence of low bone mass and its consequences as well an understanding of how to identify these patients and appropriately intervene, spine surgeons can effectively decrease the rates of adverse health outcomes related to low bone mass.

Tranexamic Acid in Thoracic and Lumbar Fusions and Perioperative Blood Loss.

STUDY DESIGN: This study was a retrospective cohort design. OBJECTIVE: The objective of this study was to examine the impact of tranexamic acid (TXA) on total perioperative wound output following thoracic and lumbar spinal fusions. SUMMARY OF BACKGROUND DATA: TXA has been extensively studied with regard to intraoperative blood loss and transfusion rates. Few studies have looked specifically at the effect of TXA on postoperative drain output. MATERIALS AND METHODS: We examined blood loss patterns in 617 consecutive adult patients undergoing lumbar and/or thoracic fusions at a single institution from January 2009 to 2016. These patients were divided into TXA and non-TXA, as well as high-dose and low-dose TXA, groups and analyzed using a propensity score to account for differences between cohorts. RESULTS: The TXA and non-TXA groups were demographically similar. The mean number of levels fused was higher in the TXA group (4.8 vs. 3.1 levels, P<0.01). There was a significant reduction in both intraoperative blood loss (77.7 mL per level, P=0.020) and postoperative drain output (83.3 mL per level, P=0.002) in the TXA group when examined on a per level fused basis, but no significant difference without controlling for a number of levels. Postoperative blood loss tended to be higher in the TXA group for surgeries involving >5 levels fused. There was a significantly less blood loss in the high-dose TKA group both intraoperatively (296.4 mL per level fused, P<0.001) and postoperatively (133.4 mL per level fused, P<0.001). CONCLUSIONS: TXA significantly reduced both intraoperative and postoperative blood loss in lumbar and thoracic fusions when examined on a per level basis. However, with surgeries involving fusions >5 levels, TXA may increase postoperative drain output, with those losses offset by reduced intraoperative blood loss. High-dose TXA further reduced both intraoperative and postoperative blood loss as compared with low-dose TXA.

Prospective Evaluation of Radiculitis following Bone Morphogenetic Protein-2 Use for Transforaminal Interbody Arthrodesis in Spine Surgery.

Study Design: Prospective observational cohort study. Purpose: This study aims to evaluate the safety and efficacy of bone morphogenetic protein-2 (BMP-2) in transforaminal lumbar interbody fusion (TLIF) with regard to postoperative radiculitis. Overview of Literature: Bone morphogenetic protein (BMP) is being used increasingly as an alternative to iliac crest autograft in spinal arthrodesis. Recently, the use of BMP in TLIF has been examined, but concerns exist that the placement of BMP close to the nerve roots may cause postoperative radiculitis. Furthermore, prospective studies regarding the use of BMP in TLIF are lacking. Methods: This prospective study included 77 patients. The use of BMP-2 was determined individually, and demographic and operative characteristics were recorded. Leg pain was assessed using the Visual Analog Scale (VAS) for pain and the Sciatica Bothersome Index (SBI) with several secondary outcome measures. The outcome data were collected at each follow-up visit. Results: Among the 77 patients, 29 were administered with BMP. Postoperative leg pain significantly improved according to VAS leg and SBI scores for the entire cohort, and no clinically significant differences were observed between the BMP and control groups. The VAS back, Oswestry Disability Index, and Short-Form 36 scores also significantly improved. A significantly increased 6-month fusion rate was noted in the BMP group (82.8% vs. 55.3%), but no significant differences in fusion rate were observed at the 12- and 24-month follow-up. Heterotopic ossification was observed in seven patients: six patients and one patient in the BMP and control groups, respectively (20.7% vs. 2.1%). However, no clinical effect was observed. Conclusions: In this prospective observational trial, the use of BMP in TLIF did not lead to significant postoperative radiculitis, as measured by VAS leg and SBI scores. Back pain and other functional outcome scores also improved, and no differences existed between the BMP and control groups. The careful use of BMP in TLIF appears to be both safe and effective.

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.

An empiric analysis of 5 counter measures against surgical site infections following spine surgery-a pragmatic approach and review of the literature.

BACKGROUND CONTEXT: Surgical site infections (SSI) following spine surgery are debilitating complications to patients and costly to the healthcare system. PURPOSE: Review the impact and cost effectiveness of 5 SSI prevention interventions on SSI rates in an orthopedic spine surgery practice at a major quaternary healthcare system over a 10-year period. STUDY DESIGN: Retrospective observational study. PATIENT SAMPLE: All of the surgical patients of the 5 spine surgeons in our department over a 10-year period were included in this study. OUTCOME MEASURES: SSI rates per year, standardized infection ratios (SIR) for laminectomies and fusions during the most recent 3-year period, year of implementation, and frequency of use of the different interventions, cost of the techniques. METHODS: The SSI prevention techniques described in this paper include application of intrawound vancomycin powder, wound irrigation with dilute betadine solution, preoperative chlorhexidine gluconate scrubs, preoperative screening with nasal swabbing, and decolonization of S. aureus, and perioperative antibiotic administration. Our institution's infection prevention and control data were analyzed for the yearly SSI rates for the orthopedic spine surgery department from 2006 to 2016. In addition, our orthopedic spine surgeons were polled to determine with what frequency and duration they have been using the different SSI prevention interventions. RESULTS: SSI rates decreased from almost 6% per year the first year of observation to less than 2% per year in the final 6 years of this study. A SIR of less than 1.0 for each year was observed for laminectomies and fusions for the period from 2013 to 2016. All surgeons polled at our institution uniformly used perioperative antibiotics, Hibiclens scrub, and the nasal swab protocol since the implementation of these techniques. Some variability existed in the frequency and duration of betadine irrigation and application of vancomycin powder. A cost analysis demonstrated these methods to be nominal compared with the cost of treating a single SSI. CONCLUSIONS: It is possible to reduce SSI rates in spine surgery with easy, safe, and cost-effective protocols, when implemented in a standardized manner.

Enterobacter Infection after Spine Surgery: An Institutional Experience.

BACKGROUND: Gram-negative surgical site infections (SSI) following spine surgery are becoming increasingly more common owing to a broad perioperative antibiotic usage targeting gram-positive organisms. Enterobacter species have been reported to be the most common gram-negative bacteria following spine surgery. METHODS: We queried our institutional database for Enterobacter SSIs after spine surgery at a single institution from 2009-2016. Relevant demographic, clinical, and operative variables were collected. We compared this cohort to patients who had non-Enterobacter SSI during the same period. RESULTS: Enterobacter species were isolated in 16 patients (9 males) diagnosed with SSI after undergoing spine surgery. This group represented 0.2% of all spine cases and 14.5% of all spinal SSIs. Seven patients (43.8%) required multiple irrigations and debridements (I&Ds) (range: 2-8), whereas only 17 of 94 patients (18.1%) with non-Enterobacter SSI required multiple I&Ds (range: 2-5, P = 0.043). Those infected with Enterobacter were associated with higher BMI (37.6 ± 12.7 vs. 31.7 ± 8, P = 0.036), earlier wound dehiscence (14.8 vs. 24.6 days, P = 0.01), polymicrobial infections (37.5% vs. 10.6%, P = 0.012), and longer length of stay (18 days [9.5-31.5] vs. 5 days [3-8], P = 0.01) when compared to non-Enterobacter SSI cohort. At an average of 24.2 months follow-up, all 15 surviving patients were infection free with no further revision surgeries needed. CONCLUSIONS: Enterobacter SSI cases were associated with higher BMI, earlier wound breakdown, polymicrobial infection and longer length of stay. Nevertheless, with vigilant surveillance and timely I&Ds, these challenging infections can be treated successfully with original implant retention in almost all cases.

Effect of teriparatide use on bone mineral density and spinal fusion: a narrative review of animal models.

Purpose of the study: Teriparatide (Human recombinant Parathyroid Hormone 1-34) is an anabolic agent that is frequently used in patients with osteoporosis and has been extensively investigated with animal model and clinical studies in current literature. The purpose of the study was to evaluate the impact of teriparatide on bone mineral density and fusion. Materials and methods: The findings from preclinical studies that have investigated the role of teriparatide in animal models are summarized in presented review. Results: Overall, the studies show an improvement in bone mineral density and increased fusion rates for osteoporotic animals undergoing spine fusion with teriparatide use. Conclusion: Further studies should be conducted for unanswered questions, such as teriparatide use before surgery, the effect on cervical fusion and surgery related complications.

Does Recombinant Human Bone Morphogenic Protein 2 Affect Perioperative Blood Loss after Lumbar and Thoracic Spinal Fusion?

STUDY DESIGN: Retrospective cohort design. PURPOSE: This study aimed to determine whether recombinant human bone morphogenic protein 2 (rhBMP-2) reduces total perioperative blood loss during lumbar and thoracic fusion. OVERVIEW OF LITERATURE: Previous studies on rhBMP-2 versus iliac crest bone grafting in thoracic and lumbar fusions have yielded mixed results regarding reductions in blood loss and have largely neglected the postoperative period when analyzing total blood loss. Additionally, these studies have been limited by heterogeneity and sample size. METHODS: We analyzed the blood loss patterns of 617 consecutive adult patients undergoing lumbar and/or thoracic fusions requiring subfascial drain placement at a single institution from January 2009 to December 2016. Patients were divided into BMP and non-BMP cohorts, and a propensity score analysis was conducted to account for the differences between cohorts. RESULTS: At a per-level fused basis, the BMP group exhibited a significant reduction in the intraoperative (66.1 mL per-level fused basis; 95% confidence interval [CI], 127.9 to 4.25 mL; p =0.036) and total perioperative blood loss (100.7 mL per-level fused basis; 95% CI, 200.9 to 0.5 mL; p =0.049). However, no significant differences were observed in an analysis when not controlling for the number of levels or when examining the postoperative drain output. CONCLUSIONS: RhBMP-2 appears to reduce both intraoperative and total blood loss during lumbar and thoracic fusions on a per-level fused basis. This total reduction in blood loss was achieved via intraoperative effects because RhBMP-2 had no significant effect on the postoperative drain output.

Postoperative Seroma Formation After Posterior Cervical Fusion with Use of RhBMP-2: A Report of Two Cases.

CASE: We present 2 cases of postoperative seroma formation following posterior cervical fusion with the use of recombinant human bone morphogenetic protein-2 (rhBMP-2). CONCLUSION: Although some who advocate for the off-label use of rhBMP-2 in patients undergoing posterior cervical spine fusion believe it to be safe, relatively little has been published regarding complication rates. We believe that rhBMP-2 carries a risk of seroma formation in patients who undergo posterior cervical fusion, which necessitates the use of a postoperative drain. Surgeons should have a low threshold for obtaining postoperative magnetic resonance imaging in a symptomatic patient.

Revision anatomic shoulder arthroplasty with posterior capsular plication for correction of posterior instability.

BACKGROUND: Revision of failed anatomic total shoulder arthroplasty or hemiarthroplasty is a challenging procedure. Restoring adequate soft tissue balance in the revision setting can be particularly problematic. When persistent posterior instability is encountered in the revision setting, options include changing component position or size, posterior capsular plication (PCP), or conversion to a reverse arthroplasty. The purpose of this study was to report the clinical and radiographic outcomes, complications, and reoperations of PCP performed in the setting of revision anatomic shoulder arthroplasty. PATIENTS AND METHODS: Between 1975 and 2013, 15 patients (16 shoulders) had PCP during revision anatomic shoulder arthroplasty. Indications for revision arthroplasty included posterior instability in 15, glenoid loosening in 3, polyethylene wear in 2, and glenoid erosion in 1 shoulder. The mean (standard deviation (SD)) age was 60.1 (12.6) years, and the median (range) follow-up was 68 (2-228) months. A retrospective chart review was conducted to obtain all data. RESULTS: At the last follow-up, nine shoulders (56%) had absence of posterior radiographic subluxation. Five (31%) cases underwent reoperation due to persistent posterior instability. Complications were observed in seven (44%) cases. Complete pain relief was achieved in four (25%) shoulders. The mean (SD) postoperative forward flexion, external rotation, and the American Shoulder and Elbow Surgeons score were 110° (41°), 40° (29°), and 62.1 (21.9), respectively. Results were excellent in two (13%), satisfactory in seven (44%), and unsatisfactory in seven (44%) shoulders. CONCLUSIONS: PCP to correct posterior instability during revision anatomic shoulder arthroplasty had an unacceptably high failure rate. In these circumstances, consideration should instead be given to conversion to a reverse shoulder arthroplasty.