Postoperative C5 Palsy after Anterior or Posterior Decompression for Degenerative Cervical Myelopathy: A Subgroup Analysis of the Multicenter, Prospective, Randomized, Phase III, CSM-Protect Clinical Trial

STUDY DESIGN

Retrospective cohort study of prospectively accrued data.

OBJECTIVE

To evaluate a large, prospective, multicentre dataset of surgically-treated DCM cases on the contemporary risk of C5 palsy with surgical approach.

SUMMARY OF BACKGROUND DATA

The influence of surgical technique on postoperative C5 palsy after decompression for degenerative cervical myelopathy (DCM) is intensely debated. Comprehensive analyses are needed using contemporary data and accounting for covariates.

METHODS

Patients with moderate to severe DCM were prospectively enrolled in the multicenter, randomized CSM-Protect clinical trial and underwent either anterior or posterior decompression between Jan 31, 2012, to May 16, 2017. The primary outcome was the incidence of postoperative C5 palsy, defined as onset of muscle weakness by at least one grade in manual muscle test at the C5 myotome with slight or absent sensory disruption after cervical surgery. Two comparative cohorts were made based on anterior or posterior surgical approach. Multivariate hierarchical mixed-effects logistic regression was used to estimate odds ratios (OR) with 95% confidence intervals (CI) for C5 palsy.

RESULTS

A total of 283 patients were included, and 53.4% underwent posterior decompression. The total incidence of postoperative C5 palsy was 7.4% and was significantly higher in patients that underwent posterior decompression compared to anterior decompression (11.26% vs. 3.03%, P=0.008). After multivariable regression, posterior approach was independently associated with greater than four times the likelihood of postoperative C5 palsy (P=0.017). Rates of C5 palsy recovery were comparable between the two surgical approaches.

CONCLUSION

The odds of postoperative C5 palsy are significantly higher after posterior decompression compared to anterior decompression for DCM. This may influence surgical decision-making when there is equipoise in deciding between anterior and posterior treatment options for DCM.

LEVEL OF EVIDENCE

Therapeutic Level II.

Laminoplasty versus laminectomy with fusion for treating multilevel degenerative cervical myelopathy

Background

Laminectomy with fusion (LF) and laminoplasty (LP) are common posterior decompression procedures used to treat multilevel degenerative cervical myelopathy (DCM). There is debate on their relative efficacy and safety for treatment of DCM. The goal of this study is to examine outcomes and costs of LF and LP procedures for DCM.

Methods

This is a retrospective review of adult patients (<18) at a single center who underwent elective LP and LF of at least 3 levels from C3-C7. Outcome measures included operative characteristics, inpatient mobility status, length of stay, complications, revision surgery, VAS neck pain scores, and changes in radiographic alignment. Oral opioid analgesic needs and hospital cost comparison were also assessed.

Results

LP cohort (n=76) and LF cohort (n=59) reported no difference in neck pain at baseline, 1, 6, 12, and 24 months postoperatively (p>.05). Patients were successfully weaned off opioids at similar rates (LF: 88%, LP: 86%). Fixed and variable costs respectively with LF cases hospital were higher, 15.7% and 25.7% compared to LP cases (p=.03 and p<.001). LF has a longer length of stay (4.2 vs. 3.1 days, p=.001). Wound-related complications were 5 times more likely after LF (13.6% vs. 5.9%, RR: 5.15) and C5 palsy rates were similar across the groups (LF: 11.9% LP: 5.6% RR: 1.8). Ground-level falls requiring an emergency department visit were more likely after LF (11.9% vs. 2.6%, p=.04).

Conclusions

When treating multilevel DCM, LP has similar rates of new or increasing axial neck pain compared to LF. LF was associated with greater hospital costs, length of stay, and complications compared to LP. LP may in fact be a less morbid and more cost-effective alternative to LF for patients without cervical deformity.

Intraoperative neuromonitoring in spine surgery: large database analysis of cost-effectiveness

BACKGROUND

Given the increased attention to functional improvement in spine surgery as it relates to activities of daily living and cost, it is critical to fully understand the health care economic impact of enabling technologies. The use of intraoperative neuromonitoring (IOM) during spine surgery has long been controversial. Questions pertaining to utility, medico-legal considerations, and cost-effectiveness continue to be unresolved. The purpose of this study is to determine the cost-effectiveness by assessing quality-of-life due to adverse events averted, decreased postoperative pain, decreased revision rates, and improved patient reported outcomes (PROs).

METHODS

The study patient population was extracted from a large multicenter database collected by a single, national IOM provider. Over 50,000 patient charts were abstracted and included in this analysis. The analysis was conducted in accordance with the second panel on cost-effectiveness health and medicine. Health-related utility was derived from questionnaire answers and expressed in quality-adjusted life years (QALYs). Both cost and QALY outcomes were discounted at a yearly rate of 3% to reflect their present value. Cost-effectiveness was calculated as the incremental cost-effectiveness ratio (ICER) for IOM. A value under the commonly accepted United States-based willingness-to-pay (WTP) threshold of $100,000 per QALY was considered cost-effective. Scenario (including litigation), probabilistic (PSA), and threshold sensitivity analyses were conducted to determine model discrimination and calibration.

RESULTS

The primary time horizon used to estimate cost and health utility was 2-years following index surgery. On average, index surgery for patients with IOM costs are approximately $1,547 greater than non-IOM cases. The base case assumed an inpatient Medicare population however multiple outpatient and payer scenarios were assessed in the sensitivity analysis. From a health system perspective IOM is cost-effective, yielding better utilities but at a higher cost than the non-IOM strategy (ICER $60,734 per QALY). From a societal perspective the IOM strategy was dominant, suggesting that better outcomes were achieved at less cost. Except for an entirely privately insured population, alternative scenarios such as, outpatient and a 50:50 Medicare/privately insured population sample also demonstrated cost-effectiveness. Notably, IOM benefits were unable to overcome the sheer costs associated many litigation scenarios, but the data was severely limited. In the 5,000 iteration PSA, at a WTP of $100,000, 74% of simulations using IOM were cost-effective.

CONCLUSIONS

The use of IOM in spine surgery is cost-effective in most scenarios examined. In the emerging and rapidly expanding field of value-based medicine, there will be an increased demand for these analyses, ensuring surgeons are empowered to make the best, most sustainable solutions for their patients and the health care system.

A real-world analysis of hybrid CDA and ACDF compared to multilevel ACDF

BACKGROUND

Multilevel anterior cervical discectomy and fusion (mACDF) is the gold standard for multilevel spinal disease; although safe and effective, mACDF can limit regular spinal motion and contribute to adjacent segment disease (ASD). Hybrid surgery, composed of ACDF and cervical disc arthroplasty, has the potential to reduce ASD by retaining spinal mobility. This study examined the safety of hybrid surgery by utilizing administrative claims data to compare real-world rates of subsequent surgery and post-procedural hospitalization within populations of patients undergoing hybrid surgery versus mACDF for multilevel spinal disease.

METHODS

This observational, retrospective analysis used the MarketScan Commercial and Medicare Database from July 2013 through June 2020. Propensity score matched cohorts of patients who received hybrid surgery or mACDF were established based on the presence of spinal surgery procedure codes in the claims data and followed over a variable post-period. Rates of subsequent surgery and post-procedural hospitalization (30- and 90-day) were compared between hybrid surgery and mACDF cohorts.

RESULTS

A total of 430 hybrid surgery patients and 2,136 mACDF patients qualified for the study; average follow-up was approximately 2 years. Similar rates of subsequent surgery (Hybrid: 1.9 surgeries/100 patient-years; mACDF: 1.8 surgeries/100 patient-years) were observed for the two cohorts. Hospitalization rates were also similar across cohorts at 30 days post-procedure (Hybrid: 0.67% hospitalized/patient-year; mACDF: 0.87% hospitalized/patient-year). At 90 days post-procedure, hybrid surgery patients had slightly lower rates of hospitalization compared to mACDF patients (0.23% versus 0.42% hospitalized/patient-year; p < 0.05).

CONCLUSIONS

Findings of this real-world, retrospective cohort study confirm prior reports indicating that hybrid surgery is a safe and effective intervention for multilevel spinal disease which demonstrates non-inferiority in relation to the current gold standard mACDF. The use of administrative claims data in this analysis provides a unique perspective allowing the inclusion of a larger, more generalizable population has historically been reported on in small cohort studies.

Acute Implantation of a Bioresorbable Polymer Scaffold in Patients With Complete Thoracic Spinal Cord Injury: 24-Month Follow-up From the INSPIRE Study

BACKGROUND

Based on 6-month data from the InVivo Study of Probable Benefit of the Neuro-Spinal Scaffold for Safety and Neurological Recovery in Patients with Complete Thoracic Spinal Cord Injury (INSPIRE) study (NCT02138110), acute implantation of an investigational bioresorbable polymer device (Neuro-Spinal Scaffold [NSS]) appeared to be safe in patients with complete thoracic spinal cord injury (SCI) and was associated with an ASIA Impairment Scale (AIS) conversion rate that exceeded historical controls.

OBJECTIVE

To evaluate outcomes through 24 months postimplantation.

METHODS

INSPIRE was a prospective, open-label, multicenter, single-arm study. Eligible patients had traumatic nonpenetrating SCI with a visible contusion on MRI, AIS A classification, neurological level of injury at T2-T12, and requirement for open spine surgery ≤96 hours postinjury.

RESULTS

Nineteen patients underwent NSS implantation. Three patients had early death determined by investigators to be unrelated to the NSS or its implantation procedure. Seven of 16 evaluable patients (44%) had improvement of ≥1 AIS grade at 6 months (primary end point) to AIS B (n = 5) or AIS C (n = 2). Three patients with AIS B at 6 months had further neurological improvement to AIS C by 12 (n = 2) and 24 (n = 1) months, respectively; none have deteriorated per latest available follow-up. No unanticipated or serious adverse device effects were reported.

CONCLUSION

In this small group of patients with complete thoracic SCI, acute NSS implantation within the spinal cord appeared to be safe with no long-term neurological issues identified during the 24-month follow-up. Patients remain stable, with additional AIS conversions observed in some patients at 12 months and beyond. These data further support the safety and probable benefit of NSS implantation in this patient population.

A Prospective Study of Lumbar Facet Arthroplasty in the Treatment of Degenerative Spondylolisthesis and Stenosis: Early Cost-effective Assessment from the Total Posterior Spine System (TOPS™) IDE Study

Background: Given the increased attention to functional improvement in spine surgery as it relates to motion preservation, activities of daily living, and cost, it is critical to fully understand the healthcare economic impact of new devices being tested in large FDA randomized controlled trials (RCT). The purpose of this analysis was to comprehensively evaluate the cost-effectiveness of the novel Total Posterior Spine (TOPS™) System investigational device compared with the trial control group, standard transforaminal lumbar interbody fusion (TLIF). Objective: To evaluate the cost-effectiveness of TOPS™ compared with TLIF. Methods: The study patient population was extracted from a multicenter RCT with current enrollment at n=121 with complete 1-year follow-up. The primary outcome was cost-effectiveness, expressed as the incremental cost-effectiveness ratio. Secondary outcomes were health-related utility, presented as quality-adjusted life-years (QALYs), and cost, calculated in US dollars. Analysis was conducted following Second Panel on Cost-Effectiveness Health and Medicine recommendations. The base case analysis utilized SF-36 survey data from the RCT. Both cost and QALY outcomes were discounted at a yearly rate of 3% to reflect their present value. A cohort Markov model was constructed to analyze perioperative and postoperative costs and QALYs for both TOPS™ and control groups. Scenario, probabilistic, and threshold sensitivity analyses were conducted to determine model discrimination and calibration. Results: The primary time horizon used to estimate cost and health utility was 2 years after index surgery. From a health system perspective, assuming a 50/50 split between Medicare and private payers, the TOPS™ cohort is cost-effective 2 years postoperatively ($6158/QALY) compared with control. At 6 years and beyond, TOPS™ becomes dominant, irrespective of payer mix and surgical setting. At willingness-to-pay thresholds of $100 000/QALY, 63% of all 5000 input parameter simulations favor TOPS, even with a $4000 upcharge vs TLIF. Discussion: The novel TOPS™ device is cost-effective compared with TLIF and becomes the dominant economic strategy over time. Conclusions: In the emerging, rapidly expanding field of value-based medicine, there will be an increased demand for these analyses, ensuring surgeons are empowered to make the best, most sustainable solutions for their patients and society.

2-Level Anterior Cervical Arthrodesis With Integrated Spacer and Plate vs Traditional Anterior Spacer and Plate System

BACKGROUND

Anterior cervical discectomy and fusion (ACDF) is a common surgery to treat cervical degenerative disc disease. Use of an anterior spacer and plate system (ASPS) results in increased disc height, higher fusion rate, lower subsidence rate, and lower complication rate than a spacer alone.1,2 However, anterior cervical plating is associated with complications, such as dysphagia, plate-screw dislodgment, soft tissue injury, neural injury, and esophageal perforation.3-9 To potentially reduce these drawbacks, integrated spacer and plate (ISP) systems have gained popularity.

METHODS

From November 2009 to October 2013, a total of 84 consecutive patients who underwent 2-level ACDF using ISP or ASPS were reviewed for clinical and radiographic outcomes. Patient-reported visual analog scale (VAS) and Neck Disability Index (NDI) scores, fusion rates, and hardware failure were determined at 1, 3, 6, 12, and 24 months after surgery.

RESULTS

Forty-three patients received ISP and 41 patients received ASPS. There were no significant differences in patient demographics between the 2 groups. Perioperative characteristics were similar, except for operative time. Postoperatively, no significant differences in VAS or NDI scores or fusion status were found. At the proximal surgical level only, there was a trend toward an earlier observed radiographic fusion rate in ASPS vs ISP, but this finding was not statistically significant (P = 0.092). One case of long-term dysphagia was reported in each group. Neither group had implant failures up to 2 years.

CONCLUSIONS

The ISP system for 2-level ACDF compared to traditional ASPS has comparable clinical and radiographic outcomes up to 2 years postoperatively. There may be a trend toward an earlier observed radiographic fusion in the ASPS group, but there was no difference in long-term dysphagia rate.

CLINICAL RELAVANCE

Integrated spacer and traditional anterior spacer for 2-level ACDF has similar clinical and radiographical outcome.

LEVEL OF EVIDENCE: 4

Efficacy of Human Adipose-Derived Stem Cells in Spinal Fusion in a Rat Ovariectomy Osteoporosis Model

AIM

To evaluate the efficacy of human adipose-derived stem cells (h-ADSCs) in spinal fusion in an osteoporotic rat model.

MATERIAL AND METHODS

Female Sprague-Dawley rats (n=40) underwent ovariectomy and were then randomly assigned into two groups: ovariectomy (OVX) (OVX + fusion) and h-ADSCs (OVX + fusion + h-ADSCs). Six weeks after OVX, we performed bilateral lumbar spinal fusion using the autologous iliac bone with or without administration of h-ADSCs. The efficacy of the spinal fusion was then assessed using manual palpation, lateral ending, morphogenic examinations, and histology six weeks the after fusion procedure.

RESULTS

Fusion bed volume was different between the two groups but not significantly. However, the fusion bed density was higher in the h-ADSC group than in the OVX group. Manual palpation (70% vs. 40%, p=0.112) and lateral bending (95% vs. 55%, p=0.011) produced higher fusion rates in the h-ADSC group than in the OVX group. Additionally, a histologic examination revealed new bone formation at the fusion bed between the lamina and implanted iliac crest bone in the h-ADSC group, whereas, in the OVX group, the fusion masses were composed of fibroblastic proliferation.

CONCLUSION

Our study demonstrates that the administration of h-ADSCs may have advantages in bone formation and consolidation but does not lead to bone overgrowth. These findings indicate that the administration of h-ADSCs is an alternative and efficient method for spinal fusion.

A Randomized Controlled Trial of Local Delivery of a Rho Inhibitor (VX-210) in Patients with Acute Traumatic Cervical Spinal Cord Injury

Acute traumatic spinal cord injury (SCI) can result in severe, lifelong neurological deficits. After SCI, Rho activation contributes to collapse of axonal growth cones, failure of axonal regeneration, and neuronal loss. This randomized, double-blind, placebo-controlled phase 2b/3 study evaluated the efficacy and safety of Rho inhibitor VX-210 (9 mg) in patients after acute traumatic cervical SCI. The study enrolled patients 14-75 years of age with acute traumatic cervical SCIs, C4-C7 (motor level) on each side, and American Spinal Injury Association Impairment Scale (AIS) Grade A or B who had spinal decompression/stabilization surgery commencing within 72 h after injury. Patients were randomized 1:1 with stratification by age (<30 vs. ≥30 years) and AIS grade (A vs. B with sacral pinprick preservation vs. B without sacral pinprick preservation). A single dose of VX-210 or placebo in fibrin sealant was administered topically onto the dura over the site of injury during decompression/stabilization surgery. Patients were evaluated for medical, neurological, and functional changes, and serum was collected for pharmacokinetics and immunological analyses. Patients were followed up for up to 12 months after treatment. A planned interim efficacy-based futility analysis was conducted after ∼33% of patients were enrolled. The pre-defined futility stopping rule was met, and the study was therefore ended prematurely. In the final analysis, the primary efficacy end-point was not met, with no statistically significant difference in change from baseline in upper-extremity motor score at 6 months after treatment between the VX-210 (9-mg) and placebo groups. This work opens the door to further improvements in the design and conduct of clinical trials in acute SCI.

Periprosthetic Osteolysis in Cervical Total Disc Arthroplasty: A Single Institutional Experience

BACKGROUND

Cervical disc arthroplasty (CDA) affords an excellent alternative to cervical fusion for the treatment of symptomatic patients with degenerative disc disease. As more surgeons perform CDAs, an understanding of the complications associated with this technique is crucial. Periprosthetic osteolysis (PO) is a rare potential complication associated with CDA.

OBJECTIVE

To highlight potential complications associated with CDA.

METHODS

A retrospective chart review of patients who underwent CDA at our institution was performed. Patient outcomes and relevant clinical and radiographical data were analyzed in addition to associated complications. Explanted devices were subjected to macroscopic and microscopic analyses.

RESULTS

A total of 88 patients were included: 68 patients underwent 1-level CDA and 20 patients had 2-level CDA. Implants used in this series included Mobi-C (Zimmer Biomet), Prestige LP (Medtronic), Secure C (Globus), Advent (Orthofix), and ProDisc C (DePuy). One patient demonstrated symptoms of myeloradiculopathy that correlated with radiographical periprosthetic osteolysis and required surgical intervention in the form of disc explantation, corpectomy, and cervical instrumented fusion. Device retrieval analysis demonstrated evidence of elevated oxidation levels and increased wear in the presence of high concentrations of metal ions and debris in the surrounding tissue. The tissue did not exhibit any immune response, infection, or acute inflammation.

CONCLUSION

PO is a potential complication of CDA that occurs irrespective of the type of implant used. We describe its occurrence and management and highlight the importance of being aware of this understated phenomenon.

A study of probable benefit of a bioresorbable polymer scaffold for safety and neurological recovery in patients with complete thoracic spinal cord injury: 6-month results from the INSPIRE study

OBJECTIVE

The aim of this study was to evaluate whether the investigational Neuro-Spinal Scaffold (NSS), a highly porous bioresorbable polymer device, demonstrates probable benefit for safety and neurological recovery in patients with complete (AIS grade A) T2-12 spinal cord injury (SCI) when implanted ≤ 96 hours postinjury.

METHODS

This was a prospective, open-label, multicenter, single-arm study in patients with a visible contusion on MRI. The NSS was implanted into the epicenter of the postirrigation intramedullary spinal cord contusion cavity with the intention of providing structural support to the injured spinal cord parenchyma. The primary efficacy endpoint was the proportion of patients who had an improvement of ≥ 1 AIS grade (i.e., conversion from complete paraplegia to incomplete paraplegia) at the 6-month follow-up visit. A preset objective performance criterion established for the study was defined as an AIS grade conversion rate of ≥ 25%. Secondary endpoints included change in neurological level of injury (NLI). This analysis reports on data through 6-month follow-up assessments.

RESULTS

Nineteen patients underwent NSS implantation. There were 3 early withdrawals due to death, which were all determined by investigators to be unrelated to the NSS or the implantation procedure. Seven of 16 patients (43.8%) who completed the 6-month follow-up visit had conversion of neurological status (AIS grade A to grade B [n = 5] or C [n = 2]). Five patients showed improvement in NLI of 1 to 2 levels compared with preimplantation assessment, 3 patients showed no change, and 8 patients showed deterioration of 1 to 4 levels. There were no unanticipated or serious adverse device effects or serious adverse events related to the NSS or the implantation procedure as determined by investigators.

CONCLUSIONS

In this first-in-human study, implantation of the NSS within the spinal cord appeared to be safe in the setting of surgical decompression and stabilization for complete (AIS grade A) thoracic SCI. It was associated with a 6-month AIS grade conversion rate that exceeded historical controls. The INSPIRE study data demonstrate that the potential benefits of the NSS outweigh the risks in this patient population and support further clinical investigation in a randomized controlled trial.Clinical trial registration no.: NCT02138110 (clinicaltrials.gov).

Effects of pre-contoured and in situ contoured rods on the mechanical strength and durability of posterior cervical instrumentation: a finite-element analysis and scanning electron microscopy investigation

STUDY DESIGN

Finite-element analysis.

OBJECTIVES

Intraoperative contouring of rods is a common procedure for spine surgeons to match the native curvature of the spine, but it may lead to premature weakening of the rod. This study investigated the effect of different bending methods on rod fatigue performance. Rod failure in the cervical spine is of clinical concern, particularly when spanning the cervicothoracic region and when considering corrective osteotomies for deformity correction and global spinal alignment.

METHODS

Finite-element models were developed to simulate rod bending (3.5 mm D, 40 mm L) to achieve a 23° angle with 3 different bending methods: French single, multiple bending, and in situ bending. Simulations were conducted in 4 steps: rod bending, rod spring back, residual stress relaxation, and F1717 mechanical test simulation.

RESULTS

French single bending resulted in the highest residual stress concentrations for both titanium (TiAlV) and cobalt chrome (CoCr) at 783 MPa and 507 MPa, respectively. During F1717 test simulation, the French single bent rod had its highest tensile stress in the middle, with 917 MPa and 623 MPa, respectively, for TiAlV and CoCr, compared to in situ (580 MPa and 586 MPa for TiAlV and CoCr) and the French multiple bent rod (765 MPa and 619 MPa for TiAlV and CoCr). The computational model found that CoCr rods made the construct least prone to deformation.

CONCLUSIONS

French single bend with TiAlV rods put the construct at highest risk of failure. CoCr rods led to minimal physical changes in microstructure while showing evidence of flattening.

Headache Relief Is Maintained 7 Years After Anterior Cervical Spine Surgery: Post Hoc Analysis From a Multicenter Randomized Clinical Trial and Cervicogenic Headache Hypothesis

OBJECTIVE

To evaluate whether anterior cervical spine surgery offers sustained (7 years) relief in patients with cervicogenic headaches (CGHs), and evaluate the difference between cervical disc arthroplasty (CDA) and anterior cervical discectomy and fusion (ACDF) for 1 and 2-level surgeries from a multicenter randomized clinical trial.

METHODS

A post hoc analysis was performed of 575 patients who underwent one or 2-level CDA or ACDF for symptomatic cervical spondylosis as part of a prospective randomized clinical trial. Assessment of pain and functional outcome was done with the Neck Disability Index (NDI) in the trial. We used the NDI headache component to assess headache outcome.

RESULTS

For both 1- and 2-level CDA and ACDF groups, there was significant headache improvement from preoperative baseline out to 7 years (p < 0.0001). For 1-level surgeries, headache improvement was similar for both groups at the 7-year point. For 2-level treatment, CDA patients had significantly improved headache scores versus ACDF patients at the 7-year point (p = 0.016).

CONCLUSION

The headache improvement noted at early follow-up was sustained over the long-term period with ACDF and CDA populations. In the case of 2-level operations, CDA patients demonstrated significantly greater benefit compared to ACDF patients over the long-term. Sinuvertebral nerve irritation at the unco-vasculo-radicular junction and anterior dura may be the cause of CGH. Therefore, it is possible that improved cervical kinematics and preservation of range of motion at adjacent uncovertebral joints in CDA may contribute to the observed difference between the groups.

Remote Virtual Spinal Evaluation in the Era of COVID-19

Background

With the COVID-19 pandemic disrupting many facets of our society, physicians and patients have begun using telemedicine as a platform for the delivery of health care. One of the challenges in implementing telemedicine for the spine care provider is completing a comprehensive spinal examination. Currently, there is no standardized methodology to complete a full spinal examination through telemedicine.

Methods

We propose a novel, remote spinal examination methodology that is easily implemented through telemedicine, where the patient is an active participant in the successful completion of his or her examination. This type of examination has been validated in a neurology setting. To facilitate the telemedicine visit, we propose that video instruction be shared with the patient prior to the telemedicine visit to increase the efficacy of the examination.

Results

Since the issuance of stay-at-home order across the states, many spine practices around the country have rapidly adopted and increased their telemedicine program to continue provide care for patients during COVID-19 pandemic. At a tertiary academic center in a busy metropolitan area, nearly 700 telemedicine visits were successfully conducted during a 4-week period. There were no remote visits being done prior to the shutdown.

Conclusions

Implementation of our proposed remote spinal examination has the potential to serve as a guideline for the spine care provider to efficiently assess patients with spine disease using telemedicine. Because these are only suggestions, providers should tailor examination to each individual patient's needs.

Level of Evidence

V.

Clinical Relevance

It is likely that physicians will incorporate telemedicine into health care delivery services even after the COVID-19 pandemic subsides because of telemedicine's efficiency in meeting patient needs. Using the standard maneuvers provided in our study, spine care providers can perform a nearly comprehensive spine examination through telemedicine. Further studies will be needed to validate the reproducibility and reliability of our methodology.

The Optimal Surgical Approach to Intradural Spinal Tumors: Laminectomy or Hemilaminectomy?

Objective Traditionally, laminectomy has been the preferred surgical approach for the resection of intradural spinal tumors. Recent trends towards minimally invasive techniques have generated interest in hemilaminectomy as an effective alternative surgical approach to resect spinal tumors. However, it remains unclear if the potential benefits of hemilaminectomies, used in other routine spinal procedures, apply to intradural spinal tumors. This report presents a six-year single institutional analysis of open resection of intradural tumors using laminectomies as compared to hemilaminectomies. Methods A single institution, multisurgeon, retrospective review of 52 patients undergoing resection of intradural spinal tumors over a six-year period was performed. Estimated blood loss, operative time, post-operative complications, length of stay, and post-operative clinical spinal instability were analyzed and compared between the two surgical techniques. Results The mean follow-up was 34 and 20 months for the laminectomy and hemilaminectomy groups, respectively. There was no statistically significant difference in operative times between the two groups (hemilaminectomy: 250.13±76.44 minutes, laminectomy: 244.49±92.85 minutes; p=0.43). Similarly, there was no difference in overall estimated blood loss (hemilaminectomy: 125±74 cc, laminectomy: 256.05±320.8 cc; p=0.27) or mean hospital length of stay (hemilaminectomy: 4.00±2.12 days, laminectomy: 5.26±3.0 days; p=0.60). No patient in either surgical group had post-operative evidence of clinical spinal instability. Conclusion Hemilaminectomy is a viable approach for the resection of intradural spinal tumors, with similar rates of post-operative complications to laminectomy when using an open surgical approach. The laminectomy allows for bilateral exposure of the entire spinal canal and neural foramina; and continues to be the preferred method for resection of large tumors with complex morphology.

Surgical management of symptomatic Tarlov cysts: cyst fenestration and nerve root imbrication-a single institutional experience

BACKGROUND

Tarlov cyst disease is a collection of cerebrospinal fluid between the endoneurium and perineurium of spinal, usually sacral, nerve roots. These cysts can become symptomatic in 20% of patients, causing lower back pain, radiculopathy, bladder and bowel dysfunction necessitating medical or surgical intervention. Different surgical and non-surgical modalities have been described for the treatment of symptomatic Tarlov cysts. However, there has been no published study that examined types of surgical techniques side by side. Our study presents a preliminary experience in the surgical management of symptomatic Tarlov cysts using two surgical techniques: cyst fenestration and nerve root imbrication.

METHODS

Retrospective chart review and analysis was done for all patients who underwent surgical intervention for symptomatic Tarlov cyst(s) in the period 2007-2013. Operative reports, preoperative and postoperative clinic visit reports were reviewed. The surgical techniques of cyst fenestration and nerve root imbrication were each described in terms of intraoperative parameters, hospital course and outcome. Modified MacNab criteria were used for evaluation of the final clinical outcome.

RESULTS

Thirty-six surgical patients were identified. Three had repeat surgery (total of 39 operations). The median age was 51 years (range, 26-84 years). Eighty-six percent were females. The presenting symptoms were low back pain (94%), sensory radiculopathy (69%), bladder and bowel dysfunction (61%), sexual dysfunction (17%) and motor dysfunction (8%). Cyst fenestration was performed in 12 patients (31%) and nerve root imbrication was done in 27 (69%). All patients in the fenestration group but only 67% in the imbrication group had fibrin glue injection into the cyst or around the reconstructed nerve root. The overall surgery-related complication rate was 28%. The complication rate was 5/12 (42%) in the fenestration group and 6/27 (22%) in the imbrication group. At the time of the last clinic visit, improved clinical outcome was noted in 9/11 (82%) and 20/25 (80%) in the fenestration and the imbrication group, respectively.

CONCLUSIONS

Cyst fenestration and nerve root imbrication are both surgical techniques to treat symptomatic Tarlov cyst(s), and both can result in clinical improvement.

Risk Factors of Secondary Lumbar Discectomy of a Herniated Lumbar Disc after Lumbar Discectomy

Objective

To study risk factors of secondary lumbar discectomy (LD) for recurrent herniated lumbar disc (HLD) and identify methods to lower the rate of recurrence.

Methods

Data from 160 patients who underwent primary LD were collected retrospectively. Demographic features, radiologic findings including Pfirrmann disc degeneration, and surgical information were analyzed to compare risks between revision and non-revision patients.

Results

The revision rate was 15% (24 patients), and the mean follow-up was 28.3 months. HLD recurrence was not related to any demographic characteristics. Primary and secondary LD were most common at the L4–5 level, but the level of operation was not significantly associated with revision. Primary LD most commonly had a Pfirrmann disc degeneration grade of 3, followed by 4. For recurrent HLD, Pfirrmann grade 4 was most common and was statistically significant (p<0.05). A body mass index (BMI) over 30 was considered obese and was significantly related with HLD revision (p<0.05).

Conclusion

Patients with high BMI or severe disc degeneration should be informed of HLD revision.

Stem and progenitor cell microenvironment for bone regeneration and repair

Stem cells reside in their native microenvironment, which provides dynamic physical and chemical cues essential to their survival, proliferation and function. A typical cell-based therapeutic approach requires the mesenchymal stem cells (MSC) to depart their native microenvironment, transplant to in-vivo environment, differentiate toward multiple lineages and participate in bone formation. The long-term survival, function and fate of MSC are dependent on the microenvironment in which they are transplanted. Transplantation of morselized autologous bone, which contains both stem cells and their native microenvironment, results in a good clinical outcome. However, implantation of bone graft substitutes does not provide the complete and dynamic microenvironment for MSC. Current bone graft therapeutics may need to be improved further to provide an optimal engineered MSC microenvironment.

Hyper-Crosslinked Carbohydrate Polymer for Repair of Critical-Sized Bone Defects

This study evaluated the safety and efficacy of a novel hyper-crosslinked carbohydrate polymer (HCCP) for the repair of critical-sized bone defects in comparison to two alternative treatments: autologous bone and poly(lactide-co-glycolide) with hyaluronic acid (PLGA/HA). Bilateral critical-sized defects were created in the lateral femoral condyles of skeletally mature New Zealand White rabbits, and they were subsequently implanted with HCCP, PLGA/HA, or autologous bone in a randomized manner. Clinical and behavioral observations were made daily, and radiological and histopathological evaluations were performed at 4, 10, and 16 weeks postimplantation. Defects implanted with HCCP showed progressive bone regeneration and bridging of the defect without adverse histological events. No signs of infection or inflammation associated with the implant material were observed in all animals that received HCCP implantation. A radiographic assessment performed at 16 weeks post-implantation showed significantly higher bone density and volume in defects implanted with HCCP compared to PLGA/HA. No statistically significant difference was observed in bone density and volume between HCCP and autologous bone. These findings demonstrate that HCCP is biocompatible, osteoconductive, and capable of promoting bone regeneration in vivo; therefore, it is suitable for both tissue engineering and the repair of critical-sized bone defects.

A novel technique for sacropelvic fixation using image-guided sacroiliac screws: a case series and biomechanical study

In this study, we sought to assess the safety and accuracy of sacropelvic fixation performed with image-guided sacroiliac screw placement using postoperative computed tomography and X-rays. The sacroiliac screws were placed with navigation in five patients. Intact specimens were mounted onto a six-degrees-of-freedom spine motion simulator. Long lumbosacral constructs using bilateral sacroiliac screws and bilateral S1 pedicle and iliac screws were tested in seven cadaveric spines. Nine sacroiliac screws were well-placed under an image guidance system (IGS); one was placed poorly without IGS with no symptoms. Both fixation techniques significantly reduced range of motion (P<0.05) at L5–S1. The research concluded that rigid lumbosacral fixation can be achieved with sacroiliac screws, and image guidance improves its safety and accuracy. This new technique of image-guided sacroiliac screw insertion should prove useful in many types of fusion to the sacrum, particularly for patients with poor bone quality, complicated anatomy, infection, previous failed fusion and iliac harvesting.

DuraSeal Exact Is a Safe Adjunctive Treatment for Durotomy in Spine: Postapproval Study

STUDY DESIGN

A nonrandomized, two-armed prospective study.

OBJECTIVE

Water-tight dural closure is paramount to the prevention of cerebrospinal fluid (CSF) leakage and associated complications. Synthetic polyethylene glycol (PEG) hydrogel has been used as an adjunct to sutured dural repair; however, its expansion postoperatively is a concern for neurological complications. A low-swell formulation of PEG sealant was introduced as DuraSeal Exact Spine Sealant System (DESS). A Post-Approval Study was performed primarily to evaluate the safety and efficacy of DESS for spinal dural repair compared to current alternatives, in a large patient population, reflecting a real-world practice.

METHODS

A total of 36 sites in the United States enrolled 429 patients treated with DESS as an adjunct to dural repair in the spinal sealant group and 406 patients treated with all other modalities in the control arm, from October 2011 to June 2016. The primary endpoint was the incidence of CSF leak within 90 days of operation. The secondary endpoints evaluated were deep surgical site infection and neurological serious adverse events.

RESULTS

The CSF leakage in the DESS group (6.6%) was not significantly different from the control group (6.5%) (p = .83), and there was no significant difference in the time to first leak. The two groups had no significant differences in deep surgical site infection (1.6% versus control 2.1%, p = .61) or proportion of subjects with neurological serious adverse events (2.9% versus control 1.6%, p = .516).

CONCLUSIONS

DuraSeal Exact Spinal Sealant is safe when compared to current alternatives for spinal dural repair.

Atlantoaxial fixation using C1 posterior arch screws: feasibility study, morphometric data, and biomechanical analysis

OBJECTIVE

C1–2 is a highly mobile complex that presents unique surgical challenges to achieving biomechanical rigidity and fusion. Posterior wiring methods have been largely replaced with segmental constructs using the C1 lateral mass, C1 pedicle, C2 pars, and C2 pedicle. Modifications to reduce surgical morbidity led to the development of C2 laminar screws. The C1 posterior arch has been utilized mostly as a salvage technique, but recent data indicate that this method provides significant rigidity in flexion-extension and axial rotation. The authors performed biomechanical testing of a C1 posterior arch screw (PAS)/C2 pars screw construct, collected morphometric data from a population of 150 CT scans, and performed a feasibility study of a freehand C1 PAS technique in 45 cadaveric specimens.

METHODS

Cervical spine CT scans from 150 patients were analyzed to determine the average C1 posterior tubercle thickness and size of C1 posterior arches. Eight cadavers were used to compare biomechanical stability of intact specimens, C1 lateral mass/C2 pars screw, and C1 PAS/C2 pars screw constructs. Paired comparisons were made using repeated-measures ANOVA and Holm-Sidak tests. Forty-five cadaveric specimens were used to demonstrate the feasibility and safety of the C1 PAS freehand technique.

RESULTS

Morphometric data showed the average craniocaudal thickness of the C1 posterior tubercle was 12.3 ± 1.94 mm. Eight percent (12/150) of cases showed thin posterior tubercles or midline defects. Average posterior arch thickness was 6.1 ± 1.1 mm and right and left average posterior arch length was 28.7 mm ± 2.53 mm and 28.9 ± 2.29 mm, respectively. Biomechanical testing demonstrated C1 lateral mass/C2 pars and C1 PAS/C2 pars constructs significantly reduced motion in flexion-extension and axial rotation compared with intact specimens (p < 0.05). The C1 lateral mass/C2 pars screw construct provided significant rigidity in lateral bending (p < 0.05). There was no statistically significant difference between the two constructs in flexion-extension, lateral bending, or axial rotation. Of the C1 posterior arches, 91.3% were successfully cannulated using a freehand technique with a low incidence of cortical breach (4.4%).

CONCLUSIONS

This biomechanical analysis indicates equivalent stability of the C1 PAS/C2 pars screw construct compared with a traditional C1 lateral mass/C2 pars screw construct. Both provide significant rigidity in flexion-extension and axial rotation. Feasibility testing in 45 cadaveric specimens indicates a high degree of accuracy with low incidence of cortical breach. These findings are supported by a separate radiographic morphometric analysis.

Reduction of direct costs in high-risk lumbar discectomy patients during the 90-day post-operative period through annular closure

Purpose

Despite being an extremely successful procedure, recurrent disc herniation is one of the most common post-discectomy complications in the lumbar spine and contributes significant health care and socioeconomic costs. Patients with large annular defects are at a high risk for reherniation, but an annular closure device (ACD) has been designed to reduce reherniation risk in this population and may, in turn, help control direct health care costs after discectomy.

Patients and methods

This analysis examined the 90-day post-discectomy cost estimates among ACD-treated (n=272) and control (discectomy alone; n=278) patients in a randomized controlled trial (RCT). Direct medical costs were estimated based on 2017 Humana and Medicare claims. Index discectomies were assumed to occur in an outpatient (OP) setting, whereas repeat discectomies were assumed to be 60% in OP and 40% in inpatient (IP). A sensitivity analysis was performed on this assumption. The device cost was not included in the analysis in order to focus on costs in the 90-day post-operative period.

Results

Within 90 days of follow-up, post-operative complications occurred in 3.3% of the ACD patients and 8.6% of the control patients (P=0.01). The average 90-day cost to treat an ACD patient was $10,257 compared to $11,299 per control patient for a 80:20 distribution of Commercial:Medicare coverage ($1,042 difference). This difference varied from $687 with 100% Medicare to $1,132 with 100% Commercial coverage. Varying the IP vs OP distribution resulted in a cost difference range of $968 to $1,156 with the ACD.

Conclusion

Augmenting discectomy with an ACD in high-risk patients with a large annular defect reduced reherniation and reoperation rates, which translated to a reduction of direct health care costs between $687 and $1,156 per patient during the 90-day post-operative period. Large annular defect patients are an easily identifiable high-risk population. Operative strategies that reduce complication risks in these patients, such as the ACD, could be advantageous from both patient care and economic perspectives.

Cost-effectiveness of a Bone-anchored Annular Closure Device Versus Conventional Lumbar Discectomy in Treating Lumbar Disc Herniations

STUDY DESIGN

Cost-utility analysis of an annular closure device (ACD) based on data from a prospective, multicenter randomized controlled trial (RCT) OBJECTIVE.: The aim of this study was to determine the cost-effectiveness of a novel ACD in a patient population at high risk for recurrent herniation following discectomy.

SUMMARY OF BACKGROUND DATA

Lumbar disc herniation patients with annular defect widths ≥6 mm are at high risk for recurrent herniation following limited discectomy. Recurrent herniation is associated with worse clinical outcomes and greater healthcare costs. A novel ACD may reduce the incidence of recurrent herniation and the associated burdens.

METHODS

A decision analytical modeling approach with a Markov method was used to evaluate the cost-effectiveness of the ACD versus conventional discectomy. Health states were created by projecting visual analogue scale (VAS) onto Oswestry Disability Index (ODI). Direct costs were calculated based on Humana and Medicare 2014 claims to represent private and public payer data, respectively. Indirect costs were calculated for lost work days using 2016 US average annual wages. The incremental cost-effectiveness ratio (ICER) in dollars per quality-adjusted life year (QALY) was compared to willingness-to-pay thresholds. Sensitivity analyses were also conducted.

RESULTS

Patients with the ACD had less symptomatic reherniations, reoperations, and complications and gained 0.0328 QALYs within the first 2 years. Total direct medical costs for the ACD group were similar to control. When productivity loss was considered, using the ACD became $2076 cheaper, per patient, than conventional discectomy. Based on direct costs alone, the ICER comparing ACD to control equaled $6030 per QALY. When indirect costs are included, the ICER became negative, which indicates that superior quality of life was attained at less cost.

CONCLUSION

For lumbar disc herniations patients with annular defects ≥6 mm, the ACD was, at 2 years, a highly cost-effective surgical modality compared to conventional lumbar discectomy.

LEVEL OF EVIDENCE

1.

Medial Branch Block Versus Vertebroplasty for 1-Level Osteoporotic Vertebral Compression Fracture: 2-Year Retrospective Study

OBJECTIVE

Percutaneous vertebroplasty (VP) and medial branch block (MBB) are used to treat osteoporotic vertebral compression fractures (VCF). We compared the clinical outcomes, radiologic changes, and economic results of MBB with those of VP in treating osteoporotic VCFs.

METHODS

A total of 164 patients with 1-level osteoporotic VCF were reviewed retrospectively. The clinical outcomes were measured with a visual analogue scale (VAS) and the Oswestry Disability Index (ODI). To compare economic costs between groups, total hospital costs at the last follow-up day were calculated.

RESULTS

The patients were divided into 2 groups: 72 patients in the conservative group treated by MBB (MBB group) and 92 patients in the group who underwent VP (VP group). The VAS and ODI scores improved significantly within postoperative week 1 in the VP group compared with the MBB group. However, the VAS and ODI scores did not differ between the groups after 1 postoperative year. After 2 years of follow-up, 14 new fractures occurred in the VP group and 3 in the MBB group. The improvement in compression ratio was statistically greater in the VP group than in the MBB group. However, after 2 years the radiologic changes between groups did not differ statistically. After the final follow-up visits, the hospital costs were significantly lower in the MBB group.

CONCLUSIONS

After 2 years of follow-up, VP and MBB both had similar efficacy in terms of pain relief and radiologic changes. MBB was more cost effective than VP. Thus, MBB alone can be a possible alternative to VP in patients with 1-level osteoporotic VCFs.

Treatment of cervical radiculopathy: A review of the evolution and economics

Background:

The surgical treatment of cervical radiculopathy has centered around anterior cervical discectomy and fusion (ACDF). Alternatively, the posterior cervical laminoforaminotomy/microdiscectomy (PCF/PCM), which results in comparable outcomes and is more cost-effective, has been underutilized.

Methods:

Here, we compared the direct/indirect costs, reoperation rates, and outcome for ACDF and PCF vs. PCM using PubMed, Medline, and Embase databases.

Results:

There were no significant differences between the re-operative rates of PCF/PCM (2% to 9.8%) versus ACDF (2% to 8%). Direct costs of ACDF were also significantly higher; the 1-year cost-utility analysis demonstrated that ACDF had $131,951/QALY while PCM had $79,856/QALY.

Conclusion:

PCF/PCM for radiculopathy are safe and more cost-effective vs. ACDF, and have similar clinical outcomes.

Rho Inhibitor VX-210 in Acute Traumatic Subaxial Cervical Spinal Cord Injury: Design of the SPinal Cord Injury Rho INhibition InvestiGation (SPRING) Clinical Trial

Traumatic spinal cord injury (SCI) is associated with a lifetime of disability stemming from loss of motor, sensory, and autonomic functions; these losses, along with increased comorbid sequelae, negatively impact health outcomes and quality of life. Early decompression surgery post-SCI can enhance patient outcomes, but does not directly facilitate neural repair and regeneration. Currently, there are no U.S. Food and Drug Administration-approved pharmacological therapies to augment motor function and functional recovery in individuals with traumatic SCI. After an SCI, the enzyme, Rho, is activated by growth-inhibitory factors and regulates events that culminate in collapse of the neuronal growth cone, failure of axonal regeneration, and, ultimately, failure of motor and functional recovery. Inhibition of Rho activation is a potential treatment for injuries such as traumatic SCI. VX-210, an investigational agent, inhibits Rho. When administered extradurally after decompression (corpectomy or laminectomy) and stabilization surgery in a phase 1/2a study, VX-210 was well tolerated. Here, we describe the design of the SPRING trial, a multicenter, phase 2b/3, randomized, double-blind, placebo-controlled clinical trial to evaluate the efficacy and safety of VX-210 (NCT02669849). A subset of patients with acute traumatic cervical SCI is currently being enrolled in the United States and Canada. Medical, neurological, and functional changes are evaluated at 6 weeks and at 3, 6, and 12 months after VX-210 administration. Efficacy will be assessed by the primary outcome measure, change in upper extremity motor score at 6 months post-treatment, and by secondary outcomes that include question-based and task-based evaluations of functional recovery.

Cervical spine fractures in osteopetrosis: a case report and review of the literature

While management of appendicular fractures has been well described in the setting of osteopetrosis, there is limited information on managing fractures of the axial spine. Here we present an osteopetrotic patient with multiple traumatic multiple, comminuted, unstable cervical spinal fractures managed with non-operative stabilization, and provide a review of the pathophysiology, genetic characteristics, and special considerations that must be explored when determining operative versus non-operative management of spinal injury in osteopetrosis. A PubMed query was performed for English articles in the literature published up to June 2016, and used the following search terms alone and in combination: "osteopetrosis", "spine", "fractures", "osteoclasts", and "operative management". Within four months after initial injury, treatment with halo vest allowed for adequate healing. The patient was asymptomatic with cervical spine dynamic radiographs confirming stability at four months. On four-year follow up examination, the patient remained without neck pain, and CT scan demonstrated partially sclerotic fracture lines with appropriate anatomical alignment. In conclusion, external halo stabilization may be an effective option for treatment of multiple unstable acute traumatic cervical spine fractures in patients with osteopetrosis. Given the challenge of surgical stabilization in osteopetrosis, further research is necessary to elucidate the optimal form of treatment in this select patient population.

Understanding United States Investigational Device Exemption Studies-Clinical Relevance and Importance for Healthcare Economics

INTRODUCTION

The US Food and Drug Administration allows a previously unapproved device to be used clinically to collect safety and effectiveness data under their Investigational Device Exemption (IDE) category. The process usually falls under 3 different trial categories: noninferiority, equivalency, and superiority. To confidently inform our patients, understanding the basic concepts of these trials is paramount. The purpose of this manuscript was to provide a comprehensive review of these topics using recently published IDE trials and economic analyses of cervical total disc replacement as illustrative examples.

CASE STUDY MOBI-C ARTIFICIAL CERVICAL DISC

In 2006, an IDE was initiated to study the safety and effectiveness of total disc replacement controlled against the standard of care, anterior cervical discectomy, and fusion. Under the IDE, randomized controlled trials comparing both 1 and 2 level cervical disease were completed. The sponsor designed the initial trial as noninferiority; however, using adaptive methodology, superiority could be claimed in the 2-level investigation.

REVIEWING HEALTHCARE ECONOMICS

Healthcare economics are critical in medical decision making and reimbursement practices. Once both cost- and quality-adjusted life-year (QALY) are known for each patient, the incremental cost-effectiveness ratio is calculated. Willingness-to-pay is controversial, but a commonly cited guideline considers interventions costing below 20 000 $/QALY strongly cost effective and more than 100 000 $/QALY as not cost effective.

CONCLUSION

While large Food and Drug Administration IDE studies are often besieged by complex statistical considerations and calculations, it is fundamentally important that clinicians understand at least the terminology and basic concepts on a practical level.

Global transcriptome analysis identifies weight regain-induced activation of adaptive immune responses in white adipose tissue of mice

Objective:

Studies have indicated that weight regain following weight loss predisposes obese individuals to metabolic disorders; however, the molecular mechanism of this potential adverse effect of weight regain is not fully understood. Here we investigated global transcriptome changes and the immune response in mouse white adipose tissue caused by weight regain.

Design:

We established a diet switch protocol to compare the effects of weight regain with those of weight gain without precedent weight loss, weight loss maintenance and chow diet. We conducted a time course analysis of global transcriptome changes in gonadal white adipose tissue (gWAT) during the weight fluctuation. Co-expression network analysis was used to identify functional modules associated with the weigh regain phenotype. Immune cell populations in gWAT were characterized by flow-cytometric immunophenotyping. Metabolic phenotypes were monitored by histological analysis of adipose tissue and liver, and blood-chemistry and body weight/composition analyses.

Results:

In total, 952 genes were differentially expressed in the gWAT in the weight regain vs the weight gain group. Upregulated genes were associated with immune response and leukocyte activation. Co-expression network analysis showed that genes involved in major histocompatibility complex I and II-mediated antigen presentation and T-cell activation function were upregulated. Consistent with the transcriptome analysis results, flow cytometry demonstrated significant increases in subsets of T cells and proinflammatory M1 macrophages in the gWAT in the weight regain as compared to the weight gain group. In addition, upregulation of adaptive immune responses was associated with high incidence of adipocyte death and upregulation of high mobility group box 1, a well-known component of damage-associated molecular patterns.

Conclusions:

Our global transcriptome analysis identified weight regain-induced activation of adaptive immune responses in mouse white adipose tissue. Results suggest that activation of adipocyte death-associated adaptive immunity in adipose tissue may contribute to unfavorable metabolic effects of weight regain following weight loss.

Cost Utility Analysis of the Cervical Artificial Disc vs Fusion for the Treatment of 2-Level Symptomatic Degenerative Disc Disease: 5-Year Follow-up

Supplemental Digital Content is Available in the Text.

BACKGROUND:

The cervical total disc replacement (cTDR) was developed to treat cervical degenerative disc disease while preserving motion.

OBJECTIVE:

Cost-effectiveness of this intervention was established by looking at 2-year follow-up, and this update reevaluates our analysis over 5 years.

METHODS:

Data were derived from a randomized trial of 330 patients. Data from the 12-Item Short Form Health Survey were transformed into utilities by using the SF-6D algorithm. Costs were calculated by extracting diagnosis-related group codes and then applying 2014 Medicare reimbursement rates. A Markov model evaluated quality-adjusted life years (QALYs) for both treatment groups. Univariate and multivariate sensitivity analyses were conducted to test the stability of the model. The model adopted both societal and health system perspectives and applied a 3% annual discount rate.

RESULTS:

The cTDR costs $1687 more than anterior cervical discectomy and fusion (ACDF) over 5 years. In contrast, cTDR had $34 377 less productivity loss compared with ACDF. There was a significant difference in the return-to-work rate (81.6% compared with 65.4% for cTDR and ACDF, respectively; P = .029). From a societal perspective, the incremental cost-effective ratio (ICER) for cTDR was −$165 103 per QALY. From a health system perspective, the ICER for cTDR was $8518 per QALY. In the sensitivity analysis, the ICER for cTDR remained below the US willingness-to-pay threshold of $50 000 per QALY in all scenarios (−$225 816 per QALY to $22 071 per QALY).

CONCLUSION:

This study is the first to report the comparative cost-effectiveness of cTDR vs ACDF for 2-level degenerative disc disease at 5 years. The authors conclude that, because of the negative ICER, cTDR is the dominant modality.

ABBREVIATIONS:

ACDF, anterior cervical discectomy and fusion

AWP, average wholesale price

CE, cost-effectiveness

CEA, cost-effectiveness analysis

CPT, Current Procedural Terminology

cTDR, cervical total disc replacement

CUA, cost-utility analysis

DDD, degenerative disc disease

DRG, diagnosis-related group

FDA, US Food and Drug Administration

ICER, incremental cost-effectiveness ratio

IDE, Investigational Device Exemption

NDI, neck disability index

QALY, quality-adjusted life years

RCT, randomized controlled trial

RTW, return-to-work

SF-12, 12-Item Short Form Health Survey

VAS, visual analog scale

WTP, willingness-to-pay

A Clinical Comparison of Anterior Cervical Plates Versus Stand-Alone Intervertebral Fusion Devices for Single-Level Anterior Cervical Discectomy and Fusion Procedures

OBJECTIVE

To compare radiologic and clinical outcomes, including rates of dysphagia and dysphonia, using a no-profile stand-alone intervertebral spacer with integrated screw fixation versus an anterior cervical plate and spacer construct for single-level anterior cervical discectomy and fusion (ACDF) procedures.

METHODS

This multicenter, randomized, prospective study included 54 patients with degenerative disc disease requiring ACDF at a single level at C3-C7. Twenty-six patients underwent single-level ACDF with stand-alone spacers, and 28 with plate fixation and spacers. Analyses were based on comparison of perioperative outcomes, radiologic and clinical metrics, and incidence of dysphagia and/or dysphonia.

RESULTS

Mean patient age was 48.8 ± 10.1years (53.7% female). No significant differences were observed between groups in operative time (101.8 ± 34.4 minutes, 114.4 ± 31.5 minutes), estimated blood loss (44.8 ± 76.5 mL, 82.5 ± 195.1 mL), or length of hospital stay (1.2 ± 0.6 days, 1.3 ± 0.6 days). Mean visual analog scale pain scores and Neck Disability Index scores improved significantly from preoperative to last follow-up (10.8 ± 2.6 months) in both groups (P < 0.05). Mean Voice Handicap Index and Eating Assessment Tool scores improved significantly from discharge to last follow-up in both groups (P < 0.05). From discharge to 6 months, the stand-alone spacers group consistently demonstrated greater improvement in Voice Handicap Index. Preoperative intervertebral disc and neuroforaminal heights increased significantly across treatment groups (P < 0.01), and no cases required surgical revision at index or adjacent levels.

CONCLUSIONS

Anterior cervical discectomy and fusion with stand-alone spacers resulted in similar clinical and radiologic outcomes as compared with plate and spacers and may help minimize postoperative dysphonia.

Relief of Cervicogenic Headaches after Single-Level and Multilevel Anterior Cervical Diskectomy: A 5-Year Post Hoc Analysis

STUDY DESIGN

Prospective study.

OBJECTIVE

Because single-level disk arthroplasty or arthrodesis in the lower subaxial spine improves headaches after surgery, we studied whether this effect may be better appreciated after two-level arthroplasty.

METHODS

We performed an independent post hoc analysis of two concurrent prospective randomized investigational device exemption trials for cervical spondylosis, one for single-level treatment and the other for two adjacent-level treatments.

RESULTS

For the one-level study, baseline mean headache scores significantly improved at 60 months for both the cervical disk arthroplasty (CDA) and anterior cervical diskectomy and fusion (ACDF) groups (p < 0.0001). However, mean improvement in headache scores was not statistically different between the investigational and control groups from 6 months through 60 months. For the two-level study, baseline mean headache scores significantly improved at 60 months for both the CDA and ACDF groups (p < 0.0001). The CDA group demonstrated greater improvement from baseline at all points; this difference was statistically significant at 6, 12, 24, 36, and 48 months but not at 18 and 60 months.

CONCLUSION

Both CDA and ACDF at either one or two levels are associated with sustained headache relief from baseline. Patients undergoing two-level arthroplasty had significantly greater improvement in headache at all points except for at 18 and 60 months. This difference in improvement was not observed in patients undergoing single-level arthroplasty. The mechanism of greater headache relief after two-level arthroplasty remains unclear.

Prospective, Randomized Comparison of One-level Mobi-C Cervical Total Disc Replacement vs. Anterior Cervical Discectomy and Fusion: Results at 5-year Follow-up

INTRODUCTION

There is increasing interest in the role of cervical total disc replacement (TDR) as an alternative to anterior cervical discectomy and fusion (ACDF). Multiple prospective randomized studies with minimum 2 year follow-up have shown TDR to be at least as safe and effective as ACDF in treating symptomatic degenerative disc disease at a single level. The purpose of this study was to compare outcomes of cervical TDR using the Mobi-C(®) with ACDF at 5-year follow-up.

METHODS

This prospective, randomized, controlled trial was conducted as a Food and Drug Administration regulated Investigational Device Exemption trial across 23 centers with 245 patients randomized (2:1) to receive TDR with Mobi-C(®) Cervical Disc Prosthesis or ACDF with anterior plate and allograft. Outcome assessments included a composite overall success score, Neck Disability Index (NDI), visual analog scales (VAS) assessing neck and arm pain, Short Form-12 (SF-12) health survey, patient satisfaction, major complications, subsequent surgery, segmental range of motion, and adjacent segment degeneration.

RESULTS

The 60-month follow-up rate was 85.5% for the TDR group and 78.9% for the ACDF group. The composite overall success was 61.9% with TDR vs. 52.2% with ACDF, demonstrating statistical non-inferiority. Improvements in NDI, VAS neck and arm pain, and SF-12 scores were similar between groups and were maintained from earlier follow-up through 60 months. There was no significant difference between TDR and ACDF in adverse events or major complications. Range of motion was maintained with TDR through 60 months. Device-related subsequent surgeries (TDR: 3.0%, ACDF: 11.1%, p<0.02) and adjacent segment degeneration at the superior level (TDR: 37.1%, ACDF: 54.7%, p<0.03) were significantly lower for TDR patients.

CONCLUSIONS

Five-year results demonstrate the safety and efficacy of TDR with the Mobi-C as a viable alternative to ACDF with the potential advantage of lower rates of reoperation and adjacent segment degeneration, in the treatment of one-level symptomatic cervical degenerative disc disease.

CLINICAL RELEVANCE

This prospective, randomized study with 5-year follow-up adds to the existing literature indicating that cervical TDR is a viable alternative to ACDF in appropriately selected patients.

LEVEL OF EVIDENCE

This is a Level I study.

Subsequent surgery rates after cervical total disc replacement using a Mobi-C Cervical Disc Prosthesis versus anterior cervical discectomy and fusion: a prospective randomized clinical trial with 5-year follow-up

OBJECTIVE Cervical total disc replacement (TDR) has been shown in a number of prospective clinical studies to be a viable treatment alternative to anterior cervical discectomy and fusion (ACDF) for the treatment of symptomatic degenerative disc disease. In addition to preserving motion, evidence suggests that cervical TDR may result in a lower incidence of subsequent surgical intervention than treatment with fusion. The goal of this study was to evaluate subsequent surgery rates up to 5 years in patients treated with TDR or ACDF at 1 or 2 contiguous levels between C-3 and C-7. METHODS This was a prospective, multicenter, randomized, unblinded clinical trial. Patients with symptomatic degenerative disc disease were enrolled to receive 1- or 2-level treatment with either TDR as the investigational device or ACDF as the control treatment. There were 260 patients in the 1-level study (179 TDR and 81 ACDF patients) and 339 patients in the 2-level study (234 TDR and 105 ACDF patients). RESULTS At 5 years, the occurrence of subsequent surgical intervention was significantly higher among ACDF patients for 1-level (TDR, 4.5% [8/179]; ACDF, 17.3% [14/81]; p = 0.0012) and 2-level (TDR, 7.3% [17/234]; ACDF, 21.0% [22/105], p = 0.0007) treatment. The TDR group demonstrated significantly fewer index- and adjacent-level subsequent surgeries in both the 1- and 2-level cohorts. CONCLUSIONS Five-year results showed treatment with cervical TDR to result in a significantly lower rate of subsequent surgical intervention than treatment with ACDF for both 1 and 2 levels of treatment. Clinical trial registration no.: NCT00389597 ( clinicaltrials.gov ).

Stereotactic guidance for navigated percutaneous sacroiliac joint fusion

Arthrodesis of the sacroiliac joint (SIJ) for surgical treatment of SIJ dysfunction has regained interest among spine specialists. Current techniques described in the literature most often utilize intraoperative fluoroscopy to aid in implant placement; however, image guidance for SIJ fusion may allow for minimally invasive percutaneous instrumentation with more precise implant placement. In the following cases, we performed percutaneous stereotactic navigated sacroiliac instrumentation using O-arm^® multidimensional surgical imaging with StealthStation^® navigation (Medtronic, Inc. Minneapolis, MN). Patients were positioned prone and an image-guidance reference frame was placed contralateral to the surgical site. O-arm® integrated with StealthStation® allowed immediate auto-registration. The skin incision was planned with an image-guidance probe. An image-guided awl, drill and tap were utilized to choose a starting point and trajectory. Threaded titanium cage(s) packed with autograft and/or allograft were then placed. O-arm® image-guidance allowed for implant placement in the SIJ with a small skin incision. However, we could not track the cage depth position with our current system, and in one patient, the SIJ cage had to be revised secondary to the anterior breach of sacrum.

Radiculopathy as Delayed Presentations of Retained Spinal Bullet

Bullet injuries to the spine may cause injury to the anatomical structures with or without neurologic deterioration. Most bullet injuries are acute, resulting from direct injury. However, in rare cases, delayed injury may occur, resulting in claudication. We report a case of intradural bullet at the L3-4 level with radiculopathy in a 30-year-old male. After surgical removal, radicular and claudicating pain were improved significantly, and motor power of the right leg also improved. We report the case of intradural bullet, which resulted in delayed radiculopathy.

Is lateral stabilization enough in thoracolumbar burst fracture reconstruction? A biomechanical investigation

BACKGROUND CONTEXT

Traditional reconstruction for burst fractures involves columnar support with posterior fixation at one or two levels cephalad/caudad; however, some surgeons choose to only stabilize the vertebral column.

PURPOSE

The aim was to distinguish biomechanical differences in stability between a burst fracture stabilized through a lateral approach using corpectomy spacers of different end plate sizes with and without integrated screws and with and without posterior fixation.

STUDY DESIGN/SETTING

This was an in vitro biomechanical study assessing thoracolumbar burst fracture stabilization.

METHODS

Six human spines (T11-L3) were tested on a six-degrees-of-freedom simulator enabling unconstrained range of motion (ROM) at ±6 N·m in flexion-extension (FE), lateral bending (LB), and axial rotation (AR) after a simulated burst fracture at L1. Expandable corpectomy spacers with/without integrated screws (Fi/F; FORTIFY Integrated/FORTIFY; Globus Medical, Inc., Audubon, PA, USA) were tested with different end plate sizes (21×23 mm, 22×40-50 mm). Posterior instrumentation (PI) via bilateral pedicle screws and rods was used one level above and one level below the burst fracture. Lateral plate (LP) fixation was tested. Devices were tested in the following order: intact; Fi21×23; Fi21×23+PI; F21×23+PI+LP; F21×23+LP; F22×40-50+LP; F22×40-50+PI+LP; Fi22×40-50+PI; Fi22×40-50.

RESULTS

In FE and AR, constructs without PI showed no significant difference (p<.05) in stability compared with intact. In LB, F22×40-50+LP showed a significant increase in stability relative to intact, but no other construct without PI reached significance. In FE and LB, circumferential constructs were significantly more stable than intact. In AR, no construct showed significant differences in motion when compared with the intact condition.

CONCLUSIONS

Constructs without posterior fixation were the least stable of all tested constructs. Circumferential fixation provided greater stability in FE and LB than lateral fixation and intact. Axial rotation showed no significant differences in any construct compared with the intact state.

Dysphagia Secondary to Anterior Osteophytes of the Cervical Spine

Study Design Retrospective case series. Objective Diffuse idiopathic skeletal hyperostosis (DISH) or Forestier disease involves hyperostosis of the spinal column. Hyperostosis involving the anterior margin of the cervical vertebrae can cause dysphonia, dyspnea, and/or dysphagia. However, the natural history pertaining to the risk factors remain unknown. We present the surgical management of two cases of dysphagia secondary to cervical hyperostosis and discuss the etiology and management of DISH based on the literature review. Methods This is a retrospective review of two patients with DISH and anterior cervical osteophytes. We reviewed the preoperative and postoperative images and clinical history. Results Two patients underwent anterior cervical osteophytectomies due to severe dysphagia. At more than a year follow-up, both patients noted improvement in swallowing as well as their associated pain. Conclusion The surgical removal of cervical osteophytes can be highly successful in treating dysphagia if refractory to prolonged conservative therapy.

Intradural extramedullary capillary hemangioma of the cauda equina: Case report and literature review

Background:

Capillary hemangiomas are benign vascular tumors that rarely occur in the neuraxis. When encountered in the spine, prompt diagnosis and complete resection is crucial. On rare instances, these lesions can acutely hemorrhage, leading to sudden neurological decline. To date, there are only 16 reported cases of intradural capillary hemangiomas in the cauda equina.

Case Description:

We report a case of an intradural extramedullary cauda equina capillary hemangioma that resulted in back pain and lower extremity motor deficit. Initial magnetic resonance (MR) imaging demonstrated a bilobular intradural L3-4 cauda equina lesion. The lesion was isointense on T1-weighted imaging, mildly hyperintense on T2-weighted images and avidly enhancing after gadolinium administration. Pathology confirmed the diagnosis of capillary hemangioma.

Conclusion:

Early diagnosis and treatment of this patient resulted in complete resection of the tumor and return of lower extremity motor function. Capillary hemangiomas should be considered in the differential diagnosis of cauda equina lesions. En bloc resection of these lesions is the mainstay of treatment.

Two-level total disc replacement with Mobi-C cervical artificial disc versus anterior discectomy and fusion: a prospective, randomized, controlled multicenter clinical trial with 4-year follow-up results

OBJECT

The purpose of this study was to evaluate the safety and effectiveness of 2-level total disc replacement (TDR) using a Mobi-C cervical artificial disc at 48 months' follow-up.

METHODS

A prospective randomized, US FDA investigational device exemption pivotal trial of the Mobi-C cervical artificial disc was conducted at 24 centers in the US. Three hundred thirty patients with degenerative disc disease were randomized and treated with cervical total disc replacement (225 patients) or the control treatment, anterior cervical discectomy and fusion (ACDF) (105 patients). Patients were followed up at regular intervals for 4 years after surgery.

RESULTS

At 48 months, both groups demonstrated improvement in clinical outcome measures and a comparable safety profile. Data were available for 202 TDR patients and 89 ACDF patients in calculation of the primary endpoint. TDR patients had statistically significantly greater improvement than ACDF patients for the following outcome measures compared with baseline: Neck Disability Index scores, 12-Item Short Form Health Survey Physical Component Summary scores, patient satisfaction, and overall success. ACDF patients experienced higher subsequent surgery rates and displayed a higher rate of adjacent-segment degeneration as seen on radiographs. Overall, TDR patients maintained segmental range of motion through 48 months with no device failure.

CONCLUSIONS

Four-year results from this study continue to support TDR as a safe, effective, and statistically superior alternative to ACDF for the treatment of degenerative disc disease at 2 contiguous cervical levels.

Clinical trial registration no.: NCT00389597 (clinicaltrials.gov)

Sequential Changes of Plasma C-Reactive Protein, Erythrocyte Sedimentation Rate and White Blood Cell Count in Spine Surgery : Comparison between Lumbar Open Discectomy and Posterior Lumbar Interbody Fusion

Objective

C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) are often utilized to evaluate for postoperative infection. Abnormal values may be detected after surgery even in case of non-infection because of muscle injury, transfusion, which disturbed prompt perioperative management. The purpose of this study was to evaluate and compare the perioperative CRP, ESR, and white blood cell (WBC) counts after spine surgery, which was proved to be non-infection.

Methods

Twenty patients of lumbar open discectomy (LOD) and 20 patients of posterior lumbar interbody fusion (PLIF) were enrolled in this study. Preoperative and postoperative prophylactic antibiotics were administered routinely for 7 days. Blood samples were obtained one day before surgery and postoperative day (POD) 1, POD3, and POD7. Using repeated measures ANOVA, changes in effect measures over time and between groups over time were assessed. All data analysis was conducted using SAS v.9.1.

Results

Changes in CRP, within treatment groups over time and between treatment groups over time were both statistically significant F(3,120)=5.05, p=0.003 and F(1,39)=7.46, p=0.01, respectively. Most dramatic changes were decreases in the LOD group on POD3 and POD7. Changes in ESR, within treatment groups over time and between treatment groups over time were also found to be statistically significant, F(3,120)=6.67, p=0.0003 and F(1,39)=3.99, p=0.01, respectively. Changes in WBC values also were be statistically significant within groups over time, F(3,120)=40.52, p<0.001, however, no significant difference was found in between groups WBC levels over time, F(1,39)=0.02, p=0.89.

Conclusion

We found that, dramatic decrease of CRP was detected on POD3 and POD7 in LOD group of non-infection and dramatic increase of ESR on POD3 and POD7 in PLIF group of non-infection. We also assumed that CRP would be more effective and sensitive parameter especially in LOD than PLIF for early detection of infectious complications. Awareness of the typical pattern of CRP, ESR, and WBC may help to evaluate the early postoperative course.

Unintended complication of intracranial subdural hematoma after percutaneous epidural neuroplasty

Percutaneous epidural neuroplasty (PEN) is a known interventional technique for the management of spinal pain. As with any procedures, PEN is associated with complications ranging from mild to more serious ones. We present a case of intracranial subdural hematoma after PEN requiring surgical evacuation. We review the relevant literature and discuss possible complications of PEN and patholophysiology of intracranial subdural hematoma after PEN.