High Lumbar Spinal Fusion Rates Using Cellular Bone Allograft Irrespective of Surgical Approach.

BACKGROUND: Mounting evidence demonstrates a promising safety and efficacy profile for spinal fusion procedures using cellular bone allograft (CBA). However, limited data exists on fusion outcomes stratified by surgical approach. The current study investigates the effectiveness of CBA in lumbar spinal fusion by surgical approach (ie, anterior, lateral, and posterior approaches). METHODS: Patients undergoing lumbar spinal fusion with CBA (Trinity Elite) were enrolled into a prospective, multi-center, open-label clinical study (NCT02969616). Fusion status was assessed by an independent review of dynamic radiographs and computed tomography images. Clinical outcome measures included quality of life (QoL; EQ5D), disability (Oswestry Disability Index [ODI]), and pain (visual analog scale [VAS]) for back pain and leg pain). Patient data extending to 24 months were analyzed in a post-hoc analysis. RESULTS: A total of 252 patients underwent interbody fusion (159 women; 93 men). Patients had a mean age of 58.3 years (SD 12.5), height of 168.3 cm (SD 10.2), and weight of 87.3 kg (SD 20.0) with a body mass index of 30.8 kg/m2 (SD 6.5). At 12 months, the overall fusion success rate for bridging bone was 98.5%; fusion success was 98.1%, 100.0%, and 97.9% for anterior, lateral, and posterior approaches, respectively. At 24 months, the overall fusion success rate for bridging bone was 98.9%; fusion success was 97.9%, 100.0%, and 98.8% for anterior, lateral, and posterior approaches, respectively. The surgical approach did not significantly impact fusion success. A significant (P < 0.0001) improvement in QoL, pain, and disability scores was also observed. Significant differences in the ODI, VAS, and EQ5D were observed between the treatment groups (P < 0.05). CONCLUSIONS: CBA represents an attractive alternative to autograft alone, reporting a high rate of successful fusion and clinical outcomes across various surgical approaches. CLINICAL RELEVANCE: The use of CBA for spinal fusion procedures, regardless of surgical approach, provides high rates of fusion with a favorable safety profile and improved patient outcomes. TRIAL REGISTRATION: NCT02969616.

The effect of classical optimizers and Ansatz depth on QAOA performance in noisy devices.

The Quantum Approximate Optimization Algorithm (QAOA) is a variational quantum algorithm for Near-term Intermediate-Scale Quantum computers (NISQ) providing approximate solutions for combinatorial optimization problems. The QAOA utilizes a quantum-classical loop, consisting of a quantum ansatz and a classical optimizer, to minimize some cost function, computed on the quantum device. This paper presents an investigation into the impact of realistic noise on the classical optimizer and the determination of optimal circuit depth for the Quantum Approximate Optimization Algorithm (QAOA) in the presence of noise. We find that, while there is no significant difference in the performance of classical optimizers in a state vector simulation, the Adam and AMSGrad optimizers perform best in the presence of shot noise. Under the conditions of real noise, the SPSA optimizer, along with ADAM and AMSGrad, emerge as the top performers. The study also reveals that the quality of solutions to some 5 qubit minimum vertex cover problems increases for up to around six layers in the QAOA circuit, after which it begins to decline. This analysis shows that increasing the number of layers in the QAOA in an attempt to increase accuracy may not work well in a noisy device.

Impact of surgical risk factors for non-union on lumbar spinal fusion outcomes using cellular bone allograft at 24-months follow-up.

BACKGROUND: The current report investigates fusion rates and patient-reported outcomes following lumbar spinal surgery using cellular bone allograft (CBA) in patients with risk factors for non-union. METHODS: A prospective, open label study was conducted in subjects undergoing lumbar spinal fusion with CBA (NCT02969616) to assess fusion success rates and patient-reported outcomes in subjects with risk factors for non-union. Subjects were categorized into low-risk (≤ 1 risk factors) and high-risk (> 1 risk factors) groups. Radiographic fusion status was evaluated by an independent review of dynamic radiographs and CT scans. Patient-reported outcome measures included quality of life (EQ-5D), Oswestry Disability Index (ODI) and Visual Analog Scales (VAS) for back and leg pain. Adverse event reporting was conducted throughout 24-months of follow-up. RESULTS: A total of 274 subjects were enrolled: 140 subjects (51.1%) were categorized into the high-risk group (> 1 risk factor) and 134 subjects (48.9%) into the low-risk group (≤ 1 risk factors). The overall mean age at screening was 58.8 years (SD 12.5) with a higher distribution of females (63.1%) than males (36.9%). No statistical difference in fusion rates were observed between the low-risk (90.0%) and high-risk (93.9%) groups (p > 0.05). A statistically significant improvement in patient-reported outcomes (EQ-5D, ODI and VAS) was observed at all time points (p < 0.05) in both low and high-risk groups. The low-risk group showed enhanced improvement at multiple timepoints in EQ-5D, ODI, VAS-Back pain and VAS-Leg pain scores compared to the high-risk group (p < 0.05). The number of AEs were similar among risk groups. CONCLUSIONS: This study demonstrates high fusion rates following lumbar spinal surgery using CBA, regardless of associated risk factors. Patient reported outcomes and fusion rates were not adversely affected by risk factor profiles. TRIAL REGISTRATION: NCT02969616 (21/11/2016).

Radiographic Fusion Outcomes for Trinity Cellular Based Allograft versus Local Bone in Posterolateral Lumbar Fusion.

INTRODUCTION: Cellular-based autograft (CBA) is being used in posterolateral lumbar arthrodesis as a fusion supplementation alternative. OBJECTIVE: To assess radiographic fusion in patients undergoing posterolateral lumbar fusion with unilateral Trinity CBA compared with contralateral local bone autograft as an internal control. METHODS: A single surgeon's practice database was interrogated for consecutive patients undergoing primary posterolateral lumbar fusion with Trinity from 2018 to 2021. Patients had Trinity applied unilaterally, with local bone autograft applied contralaterally. Fusion was assessed postoperatively by using CT after 9 months. Demographics and patient-reported outcome measures were collected preoperatively and up to 12 months postoperatively. RESULTS: Thirty-nine patients were included. There were 81 attempted fusion levels. Overall fusion rate, defined as bony bridging on at least one side of a given level for all levels fused, was 85.2% of patients. No statistically significant difference was observed in fusion rates between CBA versus local bone (79.0% versus 76.54% of levels attempted, respectively, P = 0.3527). Oswestry Disability Index improved by 3 months (P = 0.0152) and was maintained. Two patients required revision for symptomatic nonunion. CONCLUSIONS: Similar radiographic fusion rates were achieved with Trinity and local bone. Trinity is a viable alternative to local bone in posterolateral lumbar fusion.

A Comparison of 2 Cage Sizes in Biportal Endoscopic Transforaminal Lumbar Interbody Fusion.

STUDY DESIGN: Retrospective study. OBJECTIVE: This study compared the fusion and subsidence rate and clinical outcomes when using different-sized static PEEK cages in BE-TLIF. SUMMARY OF BACKGROUND DATA: Biportal endoscopic techniques for transforaminal lumbar interbody fusion (BE-TLIF) have been shown to have similar clinical and fusion outcomes with faster clinical recovery in comparison to tubular surgery. Subsidence of the interbody, however, could be a complication. METHODS: Patients who underwent 1 or 2 level BE-TLIF for degenerative and isthmic spondylolisthesis between January 2019 and January 2022 were included. A 32×10 mm cage (group A) and a 40×15 mm cage (group B) were compared. The visual analog scale (VAS) for back and leg symptoms, and Oswestry disability index (ODI) were collected. Plain radiographs and computed tomography assessed fusion and subsidence at a minimum of 12 months. RESULTS: Of the 69 enrolled patients, 39 group A patients (51 levels) and 30 group B patients (32 levels) were compared. The operation time per level was 123 ± 15.8 and 138 ± 10.5 minutes per fusion level in groups A and B, respectively (P < 0.05). ODI improved from 64.8 ± 6.2 to 15.7 ± 7.1 in group A and from 65.3 ± 5.6 to 15.1 ± 6.3 in group B at the final follow-up (P < 0.05). VAS leg and back score improvement between the groups did not differ; however, the 3-month postoperative VAS back improvement was significantly higher in group B. The final fusion rate at the final follow-up did not significantly differ; however, the fusion ratio at 1 year was higher in group B (P < 0.05). Subsidence occurred in 5 cases (9.8%) in group A and none in group B (P < 0.05). CONCLUSION: BE-TLIF using a larger cage can be performed safely with similar patient-reported outcome measures with a faster fusion rate with less subsidence risk. LEVEL OF STUDY: III.

Growing utilization of ambulatory spine surgery in Medicare patients from 2010-2021.

Background: There is growing interest in transitioning various surgical procedures to the outpatient care setting. However, for Medicare patients, the site of service for surgical procedures is influenced by regulations within the Inpatient and Outpatient Prospective Payment Systems. The purpose of this study is to quantify changes in utilization of outpatient spine surgery within the Medicare population, as well as to determine changes in outpatient volume after removal of a procedure from the "inpatient-only" list. Methods: This is a cross-sectional study of Medicare billing database information for selected spine procedures included in the Medicare Physician/Supplier Procedure Summary (PSPS) public use files from 2010-2021. These files include aggregated data from Medicare Part B fee-for-service claims, published yearly. Procedures from Healthcare Common Procedural Coding System (HCPCS) code ranges 22010-22899 and 62380-63103 were selected for analysis, limited to surgical services delivered in the inpatient, hospital outpatient department (HOPD), and ambulatory surgical center (ASC) settings. For each HCPCS code included, estimates of the total number of services and corresponding changes in volume were calculated. Results: Within the range of codes included in the study, the total number of outpatient spine procedures rose approximately 193% from 2010 to 2021, with compound annual growth rate (CAGR) for outpatient procedures per year of 9.9% for HOPDs and 15.7% for ASCs (-2.2% for inpatient procedures). Within this period, the ASC list grew from 12 procedures to 58 procedures. In 2021, the highest volume ASC procedure was HCPCS 63047, at approximately 4970 procedures. Conclusions: This study demonstrates a trend of increasing utilization of HOPDs and ASCs for spine procedures among Medicare beneficiaries from 2010 to 2021. Though HOPDs are currently more widely utilized, the ongoing additions of spine procedures to the ASC covered procedures list may shift this balance.

Cervical disc arthroplasty versus anterior cervical discectomy and fusion: an analysis of the Michigan Spine Surgery Improvement Collaborative Database.

BACKGROUND CONTEXT: Anterior cervical discectomy and fusion (ACDF) and cervical disc arthroplasty (CDA) are established surgical options for the treatment of cervical radiculopathy, myelopathy, and cervical degenerative disc disease. However, current literature does not demonstrate a clear superiority between ACDF and CDA. PURPOSE: To investigate procedural and patient-reported outcomes of ACDF and CDA among patients included in the Michigan Spine Surgery Improvement Collaborative (MSSIC) database. DESIGN: Retrospective study of prospectively collected outcomes registry data. PATIENT SAMPLE: Individuals within the MSSIC database presenting with radiculopathy, myelopathy, or cervical spondylosis refractory to typical conservative care undergoing primary ACDF or CDA from January 4, 2016, to November 5, 2021. OUTCOME MEASURES: Perioperative measures (including surgery length, length of stay, return to OR, any complications), patient-reported functional outcomes at 2-year follow-up (including return to work, patient satisfaction, PROMIS, EQ-5D, mJOA). METHODS: Patients undergoing ACDF were matched 4:1 with those undergoing CDA; propensity analysis performed on operative levels (1- and 2- level procedures), presenting condition, demographics, and comorbidities. Initial comparisons performed with univariate testing and multivariate analysis performed with Poisson generalized estimating equation models clustering on hospital. RESULTS: A total of 2,208 patients with ACDF and 552 patients with CDA were included. Baseline demographics were similar, with younger patients undergoing CDA (45.6 vs 48.6 years; p<.001). Myelopathy was more frequent in ACDF patients (30% vs 25%; p=.015). CDA was more frequently planned as an outpatient procedure. Length of stay was increased in ACDF (1.3 vs 1.0 days; p<.001). Functional outcomes were similar, with comparable proportions of patients meeting minimal clinically important difference thresholds in neck pain, arm pain, PROMIS, EQ-5D, and mJOA score. After multivariate regression, no significant differences were seen in surgical or functional outcomes. CONCLUSIONS: This study demonstrates similar outcomes for those undergoing ACDF and CDA at 2 years. Previous meta-analyses of CDA clinical trial data adhere to strict inclusion and exclusion criteria required by clinical studies; this registry data provides "real world" clinical outcomes reflecting current practices for ACDF and CDA patient selection.

Twenty-four-month interim results from a prospective, single-arm clinical trial evaluating the performance and safety of cellular bone allograft in patients undergoing lumbar spinal fusion.

BACKGROUND: Autologous bone grafts are the gold standard for spinal fusion; however, harvesting autologous bone can result in donor site infection, hematomas, increased operative time, and prolonged pain. Cellular bone allografts (CBAs) are a viable alternative that avoids the need for bone harvesting and may increase fusion success alone or when used as an adjunct material. The present study examined the efficacy and safety of CBA when used as an adjunct graft material to lumbar arthrodesis. METHODS: A prospective, single-arm, multicenter clinical trial (NCT02969616) was conducted in adult subjects (> 18 years of age) undergoing lumbar spinal fusion with CBA graft (CBA used as primary (≥ 50% by volume), with augmentation up to 50%). Radiographic fusion status was assessed by an independent review of dynamic radiographs and CT scans. Clinical outcomes were assessed with the Oswestry Disability Index (ODI), and Visual Analog Scales (VAS) score for back and leg pain. Adverse events were assessed through the 24-month follow-up period. The presented data represents an analysis of available subjects (n = 86) who completed 24 months of postoperative follow-up at the time the data was locked for analysis. RESULTS: Postoperative 24-month fusion success was achieved in 95.3% of subjects (n = 82/86) undergoing lumbar spinal surgery. Clinical outcomes showed statistically significant improvements in ODI (46.3% improvement), VAS-Back pain (75.5% improvement), and VAS-Leg pain (85.5% improvement) (p < 0.01) scores at Month 24. No subject characteristics or surgical factors were associated with pseudoarthrosis. A favorable safety profile with a limited number of adverse events was observed. CONCLUSIONS: The use of CBA as an adjunct graft material showed high rates of successful lumbar arthrodesis and significant improvements in pain and disability scores. CBA provides an alternative to autograft with comparable fusion success rates and clinical benefits. TRIAL REGISTRATION: NCT02969616.

Effect of Instrumented Spine Surgery on Length of Stay.

INTRODUCTION: Total joint arthroplasty studies have identified that surgeries that take place later in the week have a longer length of stay compared with those earlier in the week. This has not been demonstrated in studies focused on anterior cervical diskectomy and fusions or minimally invasive lumbar laminectomies. All-inclusive instrumented spine surgeries, however, have not been analyzed. The purpose of this study was to determine whether day of surgery affects length of stay and whether there are predictive patient characteristics that affect length of stay in instrumented spine surgery. METHODS: All instrumented spine surgeries in 2019 at a single academic tertiary center were retrospectively reviewed. Patients were categorized for surgical day and discharge disposition to home or a rehabilitation facility. Differences by patient characteristics in length of stay and discharge disposition were compared using Kruskal-Wallis and chi square tests along with multiple comparisons. RESULTS: Seven hundred six patients were included in the analysis. Excluding Saturday, there were no differences in length of stay based on the day of surgery. Age older than 75 years, female, American Society of Anesthesiology (ASA) classification of 3 or 4, and an increased Charlson Comorbidity Index were all associated with a notable increase in length of stay. While most of the patients were discharged home, discharge to a rehabilitation facility stayed, on average, 4.7 days longer (6.8 days compared with 2.1 days, on average) and were associated with an age older than 66 years old, an ASA classification of 3 or 4, and a Charlson Comorbidity Index of 1 to 3. CONCLUSIONS: Day of surgery does not affect length of stay in instrumented spine surgeries. Discharge to a rehabilitation facility, however, did increase the length of stay as did age older than 75 years, higher ASA classification, and increased Charlson Comorbidity Index classification.

Variational quantum approximate support vector machine with inference transfer.

A kernel-based quantum classifier is the most practical and influential quantum machine learning technique for the hyper-linear classification of complex data. We propose a Variational Quantum Approximate Support Vector Machine (VQASVM) algorithm that demonstrates empirical sub-quadratic run-time complexity with quantum operations feasible even in NISQ computers. We experimented our algorithm with toy example dataset on cloud-based NISQ machines as a proof of concept. We also numerically investigated its performance on the standard Iris flower and MNIST datasets to confirm the practicality and scalability.

Clinical Significance of Lateral Pedicle Screw Malposition in Lumbar Spine Fusion.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: Our objective was to determine whether lateral pedicle screw breach affects fusion rates and patient-reported outcomes in lumbar fusion surgery. SUMMARY OF BACKGROUND DATA: Although lateral pedicle screw malposition is considered relatively benign, few studies have focused specifically on clinical outcomes or fusion rates associated with lateral screw malposition. METHODS: Twelve-month postoperative computed tomography scans were reviewed for lateral breach, severity of breach, and fusion status. Patients with lateral breach were compared with patients with no breach. Outcome measures included Numerical Pain Rating Scale for back and leg pain, Oswestry Disability Index, and SF-36 physical function (SF-36 PF). Multivariable linear and logistic regression and were adjusted for age, procedure, level, and/or baseline pain score. RESULTS: Forty-five patients (31%) demonstrated 1 or more lateral breaches as compared with 99 patients without breach. After adjusting for baseline scores and fusion level, patients with 2 or more screw breaches experienced SF-36 PF score improvements that were 3.43 points less ( P =0.016) than patients with no lateral breach. After adjusting for baseline Numerical Pain Rating Scale, there was also a significant decrease in the odds of achieving minimally clinical important difference in back pain relief in these patients. There was no observed effect of lateral breach on the odds of successful fusion. CONCLUSIONS: The current study did not observe an association between laterally malpositioned pedicle screws and nonunion. However, results are consistent with a negative effect on SF-36 PF scores and self-reported back pain at 12 months.

Endoscopic Spine Surgery: Advertisement or Game Changer?

Endoscopic spine surgery is a rapidly developing technique. Initially used for diskectomies, endoscopic spine surgery is now considered for bony decompressions and fusions. Endoscopic spine surgery uses one or two small incisions so a camera can be inserted for visualization under high magnification while a working window is provided through the camera apparatus or through a separate incision. The suggested benefits of endoscopic spine surgery include less muscle trauma, decreased need for anesthesia, reduced blood loss, and faster recovery. The typical complications associated with spinal surgery such as bleeding, infection, nerve injury, and durotomy still exist. Although the disadvantages may have historical claims, recent literature suggests endoscopic spine surgery may outperform traditional techniques for certain pathologies. However, the learning curve of endoscopic spine surgery may present challenges with adoption by practicing spinal surgeons. The outcomes of appropriately applied endoscopic techniques provide support that endoscopic spine surgery has the potential to revolutionize spine surgery.

Unilateral Biportal Endoscopy for Lumbar Spinal Stenosis and Lumbar Disc Herniation.

Background: Unilateral biportal endoscopy (UBE) is a novel minimally invasive technique for the treatment of lumbar spinal stenosis and lumbar disc herniations. Uniportal endoscopy was utilized prior to the advent of UBE and has been considered the workhorse of endoscopic spine surgery (ESS) for lumbar discectomy and decompressive laminectomy. However, there are theoretical advantages to UBE compared with traditional uniportal endoscopy, including that the procedure utilizes typical spinal equipment that should be readily available, requires less capital cost and optical instrumentation, and provides greater operative flexibility as a result of utilizing both a working and a viewing portal7,8. Description: A 0-degree arthroscope is typically utilized for discectomy and lumbar laminectomies. The use of a radiofrequency ablator is critical to help coagulate osseous and muscle bleeders. For irrigation, gravity or a low-pressure pump, typically <40 mm Hg, can be utilized9,10. Further details regarding irrigation pressure are provided in "Important Tips." The use of a standard powered burr is typical to help osseous decompression, and Kerrison ronguers, pituitaries, osteotomes, and probes utilized in open or tubular cases suffice. Two incisions are made approximately 1 cm lateral to the midline. If working from the left side for a right-handed surgeon, the working portal is typically made at the lower laminar margin of the target level. The camera portal is then made typically 2 to 3 cm cephalad. A lateral radiograph is then utilized to confirm the portal placements. From the right side, the working portal is cephalad and the camera portal is caudal. Because of the switch, the portals may be shifted more distally.The first step is creating a working space because there is no true joint space in the spine. With use of radiofrequency ablation, a working space is created in the interlaminar space. Next, with use of a powered burr or a chiseled osteotomy, the base of the cephalad spinous process is thinned until the insertion of the ligamentum flavum is found. Next, the ipsilateral and contralateral laminae are thinned in a similar fashion. Once the osseous elements are removed, the ligamentum flavum is removed en bloc. The traversing nerve roots are checked under direct high-magnification visualization to ensure that they are decompressed. If a discectomy is necessary, standard nerve-root retractors can be utilized to retract the neural elements. With use of a blunt-tip elevator, the anular defect can be incised and the herniated disc can be removed under direct high-power visualization. In addition, a small curet can be utilized to create a defect in the weakened anulus or membrane covering the extruded disc material in order to help deliver the herniated disc material. Epidural veins are coagulated typically with use of a fine-point bipolar radiofrequency device. Alternatives: Nonoperative treatments include oral anti-inflammatory drugs, physical therapy, and epidural injections; if these fail, alternative surgical treatments include open lumbar laminectomy and/or discectomy, tubular lumbar laminectomy and/or discectomy, and other minimally invasive techniques, such as microendoscopy, uniportal endoscopy, and microscopy-assisted decompression. Rationale: UBE is a minimally invasive surgical procedure that better preserves osseous and muscular structure compared with open and tubular techniques. Conventional lumbar laminectomy involves dissection and retraction of the multifidus muscle from the spinous process to the facet joint. This exposure can damage the delicate posterior dorsal rami. Long retraction time can also lead to pressure-induced muscle atrophy and potentially increased chronic low back pain. Alternatively, smaller incisions and shorter hospital stays are possible with UBE.Similar to UBE, tubular surgery can minimize soft-tissue damage compared with open techniques; however, in a randomized trial assessing techniques for spinal stenosis surgery, Kang et al. found that UBE and tubular surgery had similarly favorable clinical outcomes at 6 months postoperatively but UBE resulted in decreased operative time, drain output, opiate use, and length of hospital stay5.Furthermore, the use of an endoscope in the biportal technique allows ultra-high magnification of the spinal pathology, decreased capital costs, and the ability to use 2 hands with freedom of movement. UBE provides clear visualization of the neural elements while keeping maximal ergonomic efficiency with the surgeon's head looking straight forward, the shoulders relaxed, and the elbows bent to 90°. Continuous irrigation through the endoscope also helps with bleeding and decreasing the risk of infection. Expected Outcomes: Long-term outcomes do not differ substantially between discectomies performed with use of the presently described technique and procedures done with more traditional minimally invasive (i.e., tubular) techniques; however, visual analogue scale scores for back pain may be better in the short term, and there is evidence of a shorter hospital stay with UBE2. Complication rates did not differ from other minimally invasive techniques. When comparing UBE and stenosis, Aygun and Abdulshafi found that UBE was associated with decreased hospital stays, operative time, and blood loss and better clinical outcomes up to 2 years postoperatively compared with tubular laminectomy12. Important Tips: The optimal hydrostatic pressure is 30 to 50 mm Hg. Pressure is determined by the distance between the fluid source and the working space. Because the working space does not change, the height of the bag decides pressure. A simple formula for pressure is calculated by dividing the distance from the working field to the irrigation source by 1.36. A rule of thumb is that if the bag is 50 to 70 cm above the patient's back, the pressure should be adequate. The advantages of using gravity rather than a pressure pump are that excessive fluid solution pressure in the epidural space can cause neurological issues such as nuchal pain, headache, and seizure11. Additionally, if the intertransverse membrane or the lateral margins of the disc are violated, hydroperitoneum can occur unknowingly due to the high-pressure system.Gravity or pump pressure of >40 mm Hg may elevate epidural pressure and mask operative bleeding. When the pump is turned off at the end of the surgical procedure, a postoperative epidural hematoma may occur because the bleeding source may not have been recognized while the pump pressure was on.Excessive pump pressure may lead to an increase in intracranial pressure, causing headache or delayed recovery from general anesthesia with stiff posture and hyperventilation.Make sure fluid is emerging from the working portal and the muscle area is not swelling to prevent soft-tissue fluid extravasation.Epidural veins are coagulated typically with a fine-point bipolar radiofrequency device.Osseous bleeding can be controlled with bone wax or a high-speed burr. Acronyms and Abbreviations: MRI = magnetic resonance imagingRF = radiofrequencyAP = anteroposterior.

Better Functional Recovery After Single-Level Compared With Two-Level Posterolateral Lumbar Fusion.

Background Multiple studies describe the outcomes of patients undergoing single-level and multilevel posterolateral lumbar fusion (PLF). However, a comparison of outcomes between single-level and two-level PLF is lacking. The aim of this prospective cohort study was to compare outcomes between single-level and two-level instrumented PLF. Methods A total of 42 patients were enrolled at nine US centers between October 2015 and June 2017. Data included radiologic outcomes, visual analog scale (VAS) Back and Leg Pain, disability per the Oswestry Disability Index (ODI), and health-related quality of life (QoL) per 36-Item Short Form Survey version 2.0 (SF-36v2) at six weeks and three, six, 12, and 24 months. Results Twelve-month and 24-month follow-ups were completed by 38 (90.5%) and 32 (76.2%) subjects, respectively. The average age was 67 years, and 54.8% were female. Twenty-six received single-level PLF, and 16 received two-level PLF. In the single-level group, there was one reoperation, two postoperative infections, and one dural tear. In the two-level group, there was one postoperative infection. The surgeon computed tomography (CT)-based evaluation of fusion rate was 67.6% (25/37) at 12-month follow-up and 94.1% (32/34) at 24-month follow-up. The third-party evaluation of fusion rate was 52.8% (19/36) at six months, 81.1% (30/37) at 12 months, and 86.5% (32/37) at 24 months. There was a tendency toward a higher fusion rate in single-level compared with two-level PLF. The ODI, SF-36v2 Mental Component Score (MCS), and VAS Back Pain and Leg Pain outcomes improved by the first follow-up visit in both the single-level and two-level groups. Improvement in the ODI was 5.86 (95% confidence interval (CI): 0.03-11.69) points greater in the single-level group compared with the two-level group. Conclusions Compared with the two-level PLF subjects, single-level PLF subjects had better functional outcomes and reported higher satisfaction with the outcome of surgery but showed similar fusion, pain, and generic health-related quality of life outcomes. Both single-level and two-level PLF subjects demonstrated high fusion rates in association with improvements in pain, functional, and quality of life outcomes, as well as high satisfaction levels.

Expandable vs Static Interbody Devices for Lateral Lumbar Interbody Fusion.

Lateral lumbar interbody fusion (LLIF) has paved a way for minimally invasive surgical treatment of a wide variety of spine pathologies. Interbody devices are used to stabilize painful disc levels, provide indirect decompression of neural elements, correct deformity, restore lordosis, and provide a sound durable fusion. Through the years, new static and expandable interbody devices have been developed in an attempt to improve radiographic and clinical outcomes in lumbar spine surgery. The purpose of this article is to explore the advantages and disadvantages between static and expandable interbody devices when used in LLIF. Specifically, this article addresses the differences in subsidence, indirect decompression, restoration of lumbar lordosis, complications, patient-reported outcomes, and cost between static and expandable interbody devices.

Index Surgery Cost of Fluoroscopic Freehand Versus Robotic-Assisted Pedicle Screw Placement in Lumbar Instrumentation: An Age, Sex, and Approach-Matched Cohort Comparison.

BACKGROUND: Spine surgery costs are notoriously high, and there are already criticisms and concerns over the economic effects. There is no consensus on cost variation with robot-assisted spine fusion (rLF) compared with a manual fluoroscopic freehand (fLF) approach. This study looks to compare the early costs between the robotic method and the freehand method in lumbar spine fusion. METHODS: rLFs by one spine surgeon were age, sex, and approach-matched to fLF procedures by another spine surgeon. Variable direct costs, readmissions, and revision surgeries within 90 days were reviewed and compared. RESULTS: Thirty-nine rLFs were matched to 39 fLF procedures. No significant differences were observed in clinical outcomes. rLF had higher total encounter costs (P < 0.001) and day-of-surgery costs (P = 0.005). Increased costs were mostly because of increased supply cost (0.0183) and operating room time cost (P < 0.001). Linear regression showed a positive relationship with operating room time and cost in rLF (P < 0.001). CONCLUSION: rLF is associated with a higher index surgery cost. The main factor driving increased cost is supply costs, with other variables too small in difference to make a notable financial effect. rLF will become more common, and other institutions may need to take a closer financial look at this more novel instrumentation before adoption.

A divide-and-conquer algorithm for quantum state preparation.

Advantages in several fields of research and industry are expected with the rise of quantum computers. However, the computational cost to load classical data in quantum computers can impose restrictions on possible quantum speedups. Known algorithms to create arbitrary quantum states require quantum circuits with depth O(N) to load an N-dimensional vector. Here, we show that it is possible to load an N-dimensional vector with exponential time advantage using a quantum circuit with polylogarithmic depth and entangled information in ancillary qubits. Results show that we can efficiently load data in quantum devices using a divide-and-conquer strategy to exchange computational time for space. We demonstrate a proof of concept on a real quantum device and present two applications for quantum machine learning. We expect that this new loading strategy allows the quantum speedup of tasks that require to load a significant volume of information to quantum devices.

Intradiscal Delivery of Anabolic Growth Factors and a Metalloproteinase Inhibitor in a Rabbit Acute Lumbar Disc Injury Model.

BACKGROUND: The purpose of our study was to examine the effect of controlled delivery of TGF-ß3, BMP-4, and TIMP-2 with a biocompatible biopolymer, chitosan, on an acutely injured intervertebral disc (IVD) in a rabbit model. METHODS: After conducting an in vitro analysis of the chondrogenic capacity of the biomolecule cocktail use (ie, TGF-ß3, BMP-4, and TIMP-2) and confirming stem cell viability in chitosan hydrogel, 15 New Zealand white rabbits underwent a lateral approach of the L1 to L4 IVDs. In each rabbit, the L2 to L3 IVD was left pristine, whereas the L1 to L2 and the L3 to L4 IVDs in each rabbit underwent nucleotomy via a 25-G needle, and the animal was subsequently randomized to no further treatment (defect only), chitosan alone, Chitosan + TGF-ß3 + BMP-4, or chitosan + TGF-ß3 + BMP-4 + TIMP-2. At 6 weeks after injury and intervention, the rabbits were killed and spines harvested to undergo quantitative T2 magnetic resonance imaging (MRI) and subsequent histologic analysis. RESULTS: In the in vitro analysis, cells treated with experimental media containing TGF-ß3, BMP-4, and TIMP-2 exhibited staining indicative of GAG production and began to exhibit a chondrocytic morphology. Quantitative T2 MRI mapping demonstrates that discs treated with chitosan, chitosan containing TGF-ß3 and BMP-4, or chitosan containing TGF-ß3, BMP-4, and TIMP-2 had consistently higher T2 relaxation times compared with defect-only discs. When the T2 relaxation times of each treatment group and defect-only discs were normalized to the healthy control disc, it was found that the T2 relaxation time of discs treated with chitosan containing TGF-ß3 and BMP-4 and discs treated with chitosan containing TGF-ß3, BMP-4, and TIMP-2 were significantly greater compared with defect-only discs (P = .048 and P = .013, respectively). Histologically, animals that received chitosan only, or chitosan with TGF-ß3 and BMP-4, showed a significantly higher intensity of Safranin-O staining (P = .016 and P = .02, respectively) compared with control discs, whereas the difference in staining intensity in animals that received chitosan loaded with TGF-ß3, BMP-4, and TIMP-2 failed to achieve significance (P = .161). CONCLUSIONS: A combination of chitosan, TGF-ß3, and BMP-4 was effective at promoting regeneration in an acute disc injury rabbit model, whereas TIMP-2 did not have a significant effect.

Radiographic Fusion Rates Following a Stand-alone Interbody Cage Versus an Anterior Plate Construct for Adjacent Segment Disease After Anterior Cervical Discectomy and Fusion.

STUDY DESIGN: Case-control. OBJECTIVES: The aim of this study was to evaluate fusion rates and compare a stand-alone cage construct with an anterior-plate construct in the setting revision anterior cervical discectomy and fusion (ACDF) for adjacent segment disease. SUMMARY OF BACKGROUND DATA: Anterior cervical discectomy and fusion are considered the criterion standard of surgical treatment for cervical myelopathy and radiculopathy. One common consequence is adjacent segment disease. Treatment of adjacent segment disease is complicated by the previous surgical implants, which may make application of an additional anterior cervical plate difficult. Stand-alone cage constructs obviate the need for removal or revision of prior implants in the setting of adjacent segment disease. METHODS: All patients undergoing surgery for adjacent segment disease in a 2-year period were identified and separated into groups based on implant construct. A control group of patients undergoing primary, single-level ACDF were selected from during the same 2-year period. Demographic variables, fusion rate, and reoperation rate were compared between groups. Continuous variables were compared using Student t test, fusion, and revision rates were compared using Pearson χ test. RESULTS: Patients undergoing primary ACDF had lower age and American Society of Anesthesia score as well as shorter operative time. Fusion rate was higher for primary ACDF compared to all patients who underwent ACDF for adjacent segment disease (95% vs. 74%). When compared to primary ACDF, patients with a stand-alone cage construct had significantly lower fusion rate (69% vs. 95%) and higher reoperation rate (14% vs. 0%). There were no significant differences in anterior plate construct versus stand-alone cage construct in terms of fusion and reoperation. CONCLUSION: Symptomatic adjacent segment disease can be managed surgically with either revision anterior plating or a stand-alone cage constructs, although our results raise questions regarding a difference in fusion rates that requires further investigation. LEVEL OF EVIDENCE: 3.

Nanometer-Scale Water Dynamics in Nafion Polymer Electrolyte Membranes: Influence of Molecular Hydrophobicity and Water Content Revisited.

The ionic conductivity of polymer electrolyte membranes (PEMs) is an essential parameter for their device applications. In water-swollen PEMs, protons and other ions are transferred through hydrophilic channels of a few nanometers in diameter at most. Thus, optimizing the chemical and physical properties of the channels can enhance the conductivity of PEMs. However, the factors controlling the conductivity have not been completely clarified. Here, we report that measurements taken near the channel walls by a special nuclear magnetic resonance technique with ≤1 nm spatial resolution showed the largest water diffusivity when ∼80% of hydrophilic sulfonic acid groups were blocked, but the proton conductivity was low. The water diffusivity was much less affected by differences in water content. Our results provide a concept for changing the properties of PEMs and a challenge to implement the improved diffusivity in a way that enhances net ion conductivity.