Freedman, Brett A.

OBJECTIVE The goal of this study was to compare different recognized definitions of osteoporosis in patients with degenerative lumbar spine pathology undergoing elective spinal fusion surgery to determine which patient population should be considered for preoperative optimization. METHODS A retrospective review of patients in whom lumbar spine surgery was planned at 2 academic medical centers was performed, and the rate of osteoporosis was compared based on different recognized definitions. Assessments were made based on dual-energy x-ray absorptiometry (DXA), CT Hounsfield units (HU), trabecular bone score (TBS), and fracture risk assessment tool (FRAX). The rate of osteoporosis was compared based on different definitions: 1) the WHO definition (T-score ≤ −2.5) at total hip or spine; 2) CT HU of < 110; 3) National Bone Health Alliance (NBHA) guidelines; and 4) “expanded spine” criteria, which includes patients meeting NBHA criteria and/or HU < 110, and/or “degraded” TBS in the setting of an osteopenic T-score. Inclusion criteria were adult patients with a DXA scan of the total hip and/or spine performed within 1 year and a lumbar spine CT scan within 6 months of the physician visit. RESULTS Two hundred forty-four patients were included. The mean age was 68.3 years, with 70.5% female, 96.7% Caucasian, and the mean BMI was 28.8. Fracture history was reported in 53.8% of patients. The proportion of patients identified with osteoporosis on DXA, HUs, NBHA guidelines, and the authors’ proposed “expanded spine” criteria was 25.4%, 36.5%, 75%, and 81.9%, respectively. Of the patients not identified with osteoporosis on DXA, 31.3% had osteoporosis based on HU, 55.1% had osteoporosis with NBHA, and 70.4% had osteoporosis with expanded spine criteria (p < 0.05), with poor correlations among the different assessment tools. CONCLUSIONS Limitations in the use of DXA T-scores alone to diagnose osteoporosis in patients with lumbar spondylosis has prompted interest in additional methods of evaluating bone health in the spine, such as CT HU, TBS, and FRAX, to inform guidelines that aim to reduce fracture risk. However, no current osteoporosis assessment was developed with a focus on improving outcomes in spinal surgery. Therefore, the authors propose an expanded spine definition for osteoporosis to identify a more comprehensive cohort of patients with potential poor bone health who could be considered for preoperative optimization, although further study is needed to validate these results in terms of clinical outcomes.

OBJECTIVE Opportunistic Hounsfield unit (HU) determination from CT imaging has been increasingly used to estimate bone mineral density (BMD) in conjunction with assessments from dual energy x-ray absorptiometry (DXA). The authors sought to compare the effect of teriparatide on HUs across different regions in the pelvis, sacrum, and lumbar spine, as a surrogate measure for the effects of teriparatide on lumbosacropelvic instrumentation. METHODS A single-institution retrospective review of patients who had been treated with at least 6 months of teriparatide was performed. All patients had at least baseline DXA as well as pre- and post-teriparatide CT imaging. HUs were measured in the pedicle, lamina, and vertebral body of the lumbar spine, in the sciatic notch, and at the S1 and S2 levels at three different points (ilium, sacral body, and sacral ala). RESULTS Forty patients with an average age of 67 years underwent a mean of 20 months of teriparatide therapy. Mean HUs of the lumbar lamina, pedicles, and vertebral body were significantly different from each other before teriparatide treatment: 343 ± 114, 219 ± 89.2, and 111 ± 48.1, respectively (p < 0.001). Mean HUs at the S1 level for the ilium, sacral ala, and sacral body were also significantly different from each other: 124 ± 90.1, −10.7 ± 61.9, and 99.1 ± 72.1, respectively (p < 0.001). The mean HUs at the S2 level for the ilium and sacral body were not significantly different from each other, although the mean HU at the sacral ala (−11.9 ± 52.6) was significantly lower than those at the ilium and sacral body (p = 0.003 and 0.006, respectively). HU improvement occurred in most regions following teriparatide treatment. In the lumbar spine, the mean lamina HU increased from 343 to 400 (p < 0.001), the mean pedicle HU increased from 219 to 242 (p = 0.04), and the mean vertebral body HU increased from 111 to 134 (p < 0.001). There were also significant increases in the S1 sacral body (99.1 to 130, p < 0.05), S1 ilium (124 vs 165, p = 0.01), S1 sacral ala (−10.7 vs 3.68, p = 0.04), and S2 sacral body (168 vs 189, p < 0.05). CONCLUSIONS There was significant regional variation in lumbar and sacropelvic HUs, with most regions significantly increasing following teriparatide treatment. The sacropelvic area had lower HU values than the lumbar spine, more regional variation, and a higher degree of correlation with BMD as measured on DXA. While teriparatide treatment resulted in HUs > 110 in the majority of the lumbosacral spine, the HUs in the sacral ala remained suggestive of severe osteoporosis, which may limit the effectiveness of fixation in this region.

Objectives: Anterior cruciate ligament reconstruction (ACLR) remains one of the most readiness-impairing surgical conditions treated in the US Military. Greater time from the index injury to surgical management (ACLR) unnecessarily prolongs the total time of limited duty. Additionally, prolonged wait times from the index injury to ACLR may increase the patient’s likelihood of sustaining concomitant or secondary intraarticular pathologies (e.g., cartilage and meniscus damage). The optimal timing for surgical reconstruction following ACL injury is debated. The purpose of this study was to determine the impact of prolonged time from injury to surgery on medical separation within five years of primary ACLR. We hypothesized that longer durations from injury to primary ACLR would be associated with greater medical separation risk within five years following surgery. Methods: We conducted a retrospective database review using data from the Military Health System Data Repository (MDR) of primary ACLR without and with concomitant procedures (meniscus [M] and/or cartilage [C]) performed within Military Treatment Facilities (MTF) from fiscal year 2009 to and/or cartilage [C]) performed within Military Treatment Facilities (MTF) from fiscal year 2009 to 2011. At the time of the ACLR, ADSMs had to be continuously enrolled for two years prior to the surgery with no history of knee surgeries in direct care (i.e., MTFs) or purchased care to ensure a higher likelihood of the index event being a primary ACLR and not an ACLR revision. A total 2,809 active duty service members were included with primary ACLR. The MDR was queried for baseline demographic, military service, and surgical information at the time of ACLR. Duty status at the time of the ACLR and cause of separation up to five years after primary ACLR were abstracted. The time from the index injury diagnosis to the primary ACLR was calculated and grouped as follows: Acute = 0-42 days, Subacute = 43-91 days, Delayed = 92-179 days, Chronic ≥ 180 days. Kaplan-Meier survivability curves were estimated and evaluated with Log-rank. Cox Proportional Hazard Models calculated Hazard Ratios (HR) with 95% confidence intervals (95% CI) to identify time from injury to surgery, demographic, and military status factors that influenced medical separation risk for patients with primary ACLR (ACLR, ACLR+M, ACLR+C, ACLR+M+C). Results: The index surgical events were categorized by isolated ACLR (48%), ACLR+M (42%), ACLR+C (5%), and ACLR+M+C (4%). Overall, the time from diagnosis to ACLR was approximately equivalent across all time categories: Acute (19%), Subacute (31%), Delayed (23%), and Chronic (25%). The probability of medical separation 5 years following primary ACLR (ACLR, ACLR+M, ACLR+C, ACLR+M+C) was highest for the delayed [92-179 days] group (17%) and lowest for the acute [0-42 days] group (12%). Patients in the delayed group were over 51% more likely to medically separate in the 5 years following the primary ACLR than those who were treated within 42 days from injury (acute group). The difference between the acute group and subacute or chronic was not statistically significant. Those in infantry and combat support related military occupation classifications were 27% more likely to medically separate. Service members in the Army were more than 4.5 times more likely to medically separate compared to those in the Air Force. Smoking and BMI over 29 also increased the risk of medical separation within 5 years by 42% and 91%, respectively. The type of injury at the index event (ACLR, ACLR+M, ACLR+C, ACLR+M+C) did not significantly influence the likelihood of medical separation risk. Conclusion: Delay in treatment from injury to primary ACLR increases the number of limited duty days, effects medical readiness of ADSM, and military retention rates post ACLR. Specifically, when primary ACLR is delayed 3 to 6 months from injury, ADSM have a 51% increased likelihood of military medical separation risk in the 5 years following the ACLR than if they would have been treated within 41 days of injury. Early recognition of ACL tears as well as availability of surgeons and Operative Rooms (ORs) should be evaluated to determine their contribution to the delay in ACLR in the MHS.

OBJECTIVEThe National Surgical Quality Improvement Program (NSQIP) and National Readmissions Database (NRD) are two widely used databases for research studies. However, they may not provide generalizable information in regard to individual institutions. Therefore, the objective of the present study was to evaluate 30-day readmissions following anterior cervical discectomy and fusion (ACDF) and posterior lumbar fusion (PLF) procedures by using these two national databases and an institutional cohort.METHODSThe NSQIP and NRD were queried for patients undergoing elective ACDF and PLF, with the addition of an institutional cohort. The outcome of interest was 30-day readmissions following ACDF and PLF, which were unplanned and related to the index procedure. Subsequently, univariable and multivariable analyses were conducted to determine the predictors of 30-day readmissions by using both databases and the institutional cohort.RESULTSAmong all identified risk factors, only hypertension was found to be a common risk factor between NRD and the institutional cohort following ACDF. NSQIP and the institutional cohort both showed length of hospital stay to be a significant predictor for 30-day related readmission following PLF. There were no overlapping variables among all 3 cohorts for either ACDF or PLF. Additionally, the national databases identified a greater number of risk factors for 30-day related readmissions than did the institutional cohort for both procedures.CONCLUSIONSOverall, significant differences were seen among all 3 cohorts with regard to top predictors of 30-day unplanned readmissions following ACDF and PLF. The higher quantity of significant predictors found in the national databases may suggest that looking at single-institution series for such analyses may result in underestimation of important variables affecting patient outcomes, and that big data may be helpful in addressing this concern.

Case: We report a case of implant failure after primary 2-level M6-cervical disc replacement (M6-C; Spinal Kinetics) at C4-5 and C5-6. At revision surgery, a full-thickness tear was identified in the sheath of the C5-6 implant. Histology from periprosthetic tissue demonstrated polyethylene particles without acute inflammation. Tissue cultures were positive for Propionibacterium acnes , but ultrasonicate cultures were negative for both prostheses. An independent laboratory test confirmed mechanical failure of the C5-6 prosthesis. Conclusion: This is the first report of mechanical failure associated with wear-debris osteolysis after M6-C disc arthroplasty. Therefore, continued surveillance after CTDR is necessary.

Study Design: Retrospective cohort study. Objectives: Studies in the lumbar spine suggest a correlation between sarcopenia and worse patient outcomes. The purpose of this study was to determine whether paraspinal Goutalier grade of fat degeneration is associated with patient-reported outcomes in patients undergoing anterior cervical discectomy and fusion (ACDF). Methods: We performed a retrospective review of a prospective cohort of patients undergoing 1- to 3-level ACDF at a single institution between the years 2011-2014. We utilized preoperative magnetic resonance images to classify patients into Goutalier grades. Patient-reported outcomes, including Neck Disability Index (NDI), RAND score, and EQ-5D score were collected and analyzed according to patients’ Goutalier grade. Results: We identified 69 patients for inclusion. A total of 29 patients were classified as Goutalier 0-1 (group 1), 29 were Goutalier 1.5-2 (group 2), and 11 were Goutalier 2.5-4.0 (group 3). All Goutalier groups experienced significant improvement in all 3 outcome scores. Average postoperative NDI scores were 25.3 in group 1, 13.9 in group 2, and 25.1 in group 3 ( P = .02). The percentage of patients in each group reporting worse disability after surgery was 17.2%, 3.3%, and 9.1%, respectively ( P = .05). No statistically significant difference was seen between groups in postoperative EQ-5D ( P = .07) or RAND scores ( P > .05). Conclusions: The present study is the first to assess the association between cervical paraspinal muscle Goutalier grade and patient-reported outcomes following ACDF. Based on our study, patients with worse cervical paraspinal degeneration may benefit from improved symptom relief in comparison to patients with a lesser degree of degeneration undergoing ACDF.

OBJECTIVEPlatelet-rich plasma (PRP) is a biological agent obtained by centrifuging a sample of blood and retrieving a high concentration of platelets and plasma components. The concentrate is then stimulated for platelet secretion of various growth factors and cytokines. Although it is not widely used in clinical practice, its role in augmenting bony union among patients undergoing spinal fusion has been assessed in several clinical studies. The objective of this study was to perform a systematic review and meta-analysis of the existing literature to determine the efficacy of PRP use in spinal fusion procedures.METHODSA comprehensive literature search was conducted using PubMed, Scopus, and EMBASE for studies from all available dates. From eligible studies, data regarding the fusion rate and method of assessing fusion, estimated blood loss (EBL), and baseline and final visual analog scale (VAS) scores were collected as the primary outcomes of interest. Patients were grouped by those undergoing spinal fusion with PRP and bone graft (PRP group) and those only with bone graft (graft-only group).RESULTSThe literature search resulted in 207 articles. Forty-five full-text articles were screened, of which 11 studies were included, resulting in a meta-analysis including 741 patients. Patients without PRP were more likely to have a successful fusion at the last follow-up compared with those with PRP in their bone grafts (OR 0.53, 95% CI 0.34–0.84; p = 0.006). There was no statistically significant difference with regard to change in VAS scores (OR 0.00, 95% CI −2.84 to 2.84; p > 0.99) or change in EBL (OR 3.67, 95% CI −67.13–74.48; p = 0.92) between the groups.CONCLUSIONSThis study found that the additional use of PRP was not associated with any significant improvement in patient-reported outcomes and was actually found to be associated with lower fusion rates compared with standard grafting techniques. Thus, PRP may have a limited role in augmenting spinal fusion.

Study Design: This was a retrospective cohort study. Objectives: When anterior cervical osteophytes become large enough, they may cause dysphagia. There is a paucity of work examining outcomes and complications of anterior cervical osteophyte resection for dysphagia. Methods: Retrospective review identified 19 patients who underwent anterior cervical osteophyte resection for a diagnosis of dysphagia. The mean age was 71 years and follow-up, 4.7 years. The most common level operated on was C3-C4 (13, 69%). Results: Following anterior cervical osteophyte resection, 79% of patients had improvement in dysphagia. Five patients underwent cervical fusion; there were no episodes of delayed or iatrogenic instability requiring fusion. Fusion patients were younger (64 vs 71 years, P = .05) and had longer operative times (315 vs 121 minutes, P = .01). Age of 75 years or less trended toward improvement in dysphagia ( P = .09; OR = 18.8; 95% CI 0.7-478.0), whereas severe dysphagia trended toward increased complications ( P = .07; OR = 11.3; 95% CI = 0.8-158.5). Body mass index, use of an exposure surgeon, diffuse idiopathic skeletal hyperostosis diagnosis, surgery at 3 or more levels, prior neck surgery, and fusion were not predictive of improvement or complication. Conclusions: Anterior cervical osteophyte resection improves swallowing function in the majority of patients with symptomatic osteophytes. Spinal fusion can be added to address stenosis and other underlying cervical disease and help prevent osteophyte recurrence, whereas intraoperative navigation can be used to ensure complete osteophyte resection without breaching the cortex or entering the disc space. Because of the relatively high complication rate, patients should undergo thorough multidisciplinary workup with swallow evaluation to confirm that anterior cervical osteophytes are the primary cause of dysphagia prior to surgery.

Study Design. Review. Objective. To provide practicing spine surgeons a primer with key insights for reading, interpreting, and clinically integrating systematic reviews and meta-analyses. Summary of Background Data. Evidence-based medicine (EBM) refers to a family of standardized techniques for critical appraisal of clinical research. Within the contemporary spine literature, EBM is most commonly encountered in the form of systematic reviews and meta-analyses. Although these analytic techniques are potentially useful when appropriately applied to well-formulated questions with adequate primary data in the literature, the rapid and somewhat indiscriminate increase in volume of systematic reviews and meta-analyses published may be associated with an overall dilution in their quality, as well as misperceptions regarding the applicability of particular EBM studies to spine surgery in general. Methods. The collective experience of spine specialists with vested interests in advancing EBM and its utility was summarized into a primer. Results. We emphasize components that are pertinent methodologically (search strategy, study number, meta-analysis, bias, and certainty), and pertinent clinically (outcomes) to interpreting, and clinically integrating systematic reviews and meta-analyses into spine surgery practice. Conclusions. Armed with these insights into these five perspectives, we anticipate that practicing spine surgeons will be better equipped to interpret systematic reviews and meta-analyses in a fashion that will meaningfully impact their patient care. Level of Evidence: 2

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.