Changes in lumbar lordosis and predicted minimum 5-year surgical outcomes after short-segment transforaminal lumbar interbody fusion.

Although most patients who undergo transforaminal lumbar interbody fusion (TLIF) show favorable surgical results, some still have unfavorable results for various reasons. This study aimed to investigate the influence of differences in lumbar lordosis (LL) between the standing and supine positions (DiLL: supine LL-standing LL) on minimum 5-year surgical outcomes after short-segment TLIF. Ninety-one patients with lumbar degenerative disease who underwent short-segment TLIF (1-2 levels) were categorized based on preoperative differences in LL as DiLL (+) and DiLL (-). Comparison and correlation analyses were performed. The incidence of adjacent segment disease (ASD) by radiology (R-ASD) and symptomatic ASD (S-ASD), bony fusion rates, and pre- and postoperative clinical scores (visual analog scale [VAS]; Japanese Orthopaedic Association [JOA] score; Oswestry disability index (ODI); and Nakai's score) were evaluated. Postoperatively, VAS for low back pain (LBP) in the sitting position, JOA scores for LBP, lower leg pain, intermittent claudication, ODI, and Nakai's score were significantly worse in the DiLL (+) group than in the DiLL (-) group. DiLL values were significantly correlated with VAS for LBP, ODI, and Nakai's score, postoperatively. Positive DiLL values were associated with poorer postoperative outcomes. DiLL is a simple and useful method for predicting mid-term outcomes after TLIF.

Biomechanical Evaluation of Stand-Alone Oblique Lateral Lumbar Interbody Fusion Under 3 Different Bone Mineral Density Conditions: A Finite Element Analysis.

OBJECTIVE: To evaluate the biomechanical stability of stand-alone (SA) oblique lateral interbody fusion (OLIF) under different bone mineral density conditions. METHODS: The finite element model of L2-L5 was reconstructed and verified via computed tomography scan images (M0). The L4-L5 segment of SA OLIF was created based on the validation model. By changing bone mineral density, SA OLIF was established in the normal bone mineral density group (M1), osteopenia group (M2), and osteoporosis group (M3). A 500 N vertical axial preload was imposed on the superior surface of L2, and a 10 N-m moment was applied on the L2 superior surface along the radial direction to simulate 6 different physiological motions: flexion, extension, left and right lateral bending, left and right rotation. RESULTS: Compared with M0, the range of motion of the fusion segment was significantly reduced, and the maximum stress of the upper and lower end plates was significantly increased in all motion modes. Compared with M1, the maximum relative increases of range of motion, cephalic end-plate stress and tail end-plate stress of M2 in the L4-L5 segment were 39.1%, 9.9%, and 10.7%, and the maximum increases of the above parameters in M3 were 100%, 28.9%, and 31.6%. The maximum stress of the tail end plate of the M3 model during flexion was 54.617 MPa, which was very close to the yield stress of the lamellar bone (60 MPa). CONCLUSIONS: With the increase of the degree of osteoporosis, the maximum stress on the upper and lower end plates of the fusion segment increased significantly, thus increasing the potential risk of implant subsidence. SA OLIF could not provide sufficient stability for patients with osteoporosis.

Cervical spine alignment and clinical outcomes after multilevel anterior cervical decompression and fusion with or without plate: A minimal 5-year follow-up of a CONSORT-compliant article.

ABSTRACT: It was reported imperative on cervical sagittal alignment reconstruction after anterior multilevel procedures with self-locked stand-alone cage (SSC) or anterior cage-with-plate (ACP) system multilevel while there was little knowledge about the relationship on cervical alignment and clinical outcomes.To identify the importance of cervical sagittal alignment after 3-level anterior cervical discectomy and fusion on cervical spondylotic myelopathy with SSC and ACP system.Seventy-seven patients with SSC system (SSC group) and 52 cases with ACP system (ACP group) from February 2007 to September 2013 were enrolled with well-matched demographics. Cervical alignment included C2-7 lordosis (CL), operated-segment cervical lordosis (OPCL), upper and lower adjacent-segment cervical lordosis, range of motion of upper and lower adjacent segment at preoperation, immediate postoperation, and the final follow-up. Clinical outcomes contained the neck disability index (NDI), the Japanese Orthopaedic Association (JOA) score, visual analogous scale (VAS) of arm and neck and adjacent segment degeneration (ASD). Patients were then divided into CL improved subgroup (IM subgroup) and non-improved subgroup (NIM subgroup).There were improvements on CL and OPCL in both groups. The change of CL and OPCL larger in ACP group (P < .05) but upper adjacent-segment cervical lordosis/lower adjacent-segment cervical lordosis and range of motion of upper adjacent segment/range of motion of lower adjacent segment were of no significance. NDI, JOA, and VAS got improvement in both groups at immediate postoperation and the final follow-up while ASD was in no difference between SSC and ACP group. A total of 80 patients (39 vs 41) acquired CL improvement with a larger population in ACP group. There were no differences on the rate of ASD, NDI, JOA, VAS, and their change between IM and NIM subgroup. The changes of CL were not correlated to NDI, JOA, VAS, and their change.SSC and ACP group both provide improved OPCL and efficacy on 3-level cervical spondylotic myelopathy with little impact on adjacent segment. The change of CL is not correlated to clinical outcomes.

Lateral migration resistance of screw is essential in evaluating bone screw stability of plate fixation.

Conventional evaluation of the stability of bone screws focuses on pullout strength, while neglecting lateral migration resistance. We measured pullout strength and lateral migration resistance of bone screws and determined how these characteristics relate to screw stability of locking plate (LP) and dynamic compression plate (DCP) fixation. Pullout strength and lateral migration resistance of individual bone screws with buttress, square, and triangular thread designs were evaluated in polyurethane foam blocks. The screw types with superior performance in each of these characteristics were selected. LP and DCP fixations were constructed using the selected screws and tested under cyclic craniocaudal and torsional loadings. Subsequently, the association between individual screws' biomechanical characteristics and fixation stability when applied to plates was established. Screws with triangular threads had superior pullout strength, while screws with square threads demonstrated the highest lateral migration resistance; they were selected for LP and DCP fixations. LPs with square-threaded screws required a larger force and more cycles to trigger the same amount of displacement under both craniocaudal and torsional loadings. Screws with triangular and square threads showed no difference in DCP fixation stability under craniocaudal loading. However, under torsional loading, DCP fixation with triangular-threaded screws demonstrated superior fixation stability. Lateral migration resistance is the primary contributor to locking screw fixation stability when applied to an LP in resisting both craniocaudal and torsional loading. For compression screws applied to a DCP, lateral migration resistance and pullout strength work together to resist craniocaudal loading, while pullout strength is the primary contributor to the ability to resist torsional loading.

Analytical Problems with Preparation of Paraspinal Tissues from Patients with Spinal Fusion for Analysis of Titanium.

Preparation of paraspinal tissue of patients with implants for elemental analysis is a challenge because it contains titanium in the ionic form, as well as metallic debris. Most literature reports focus on dissolving the tissue, but the impact of digestion conditions on metallic debris of Ti has not been investigated. In our work, various digestion conditions, including systems, compositions of oxidising mixture, and time, were tested aiming (i) to digest the tissue without digestion of metallic titanium to quantify soluble Ti and (ii) to digest metallic titanium debris to asses total Ti content in tissue. The experiments were performed in a closed mode using a microwave-assisted system and a carbon heating block. Our study revealed that total digestion of titanium was impossible in the tested conditions and the maximal level of digested titanium was below 70%. The mineralisation with the use of concentrated nitric acid was optimal to prepare paraspinal samples to analyse the soluble titanium form because metallic titanium passivated and did not migrate to the solution. The elaborated conditions were applied to determine titanium ion in the periimplant tissue of patients with three different titanium-based surgical systems, including traditional growing rod (TGR), guided growth systems (GGS), and vertical expandable prosthesis titanium rib (VEPTR).

Artificial Intelligence-enabled, Real-time Intraoperative Ultrasound Imaging of Neural Structures Within the Psoas: Validation in a Porcine Spine Model.

STUDY DESIGN: Experimental in-vivo animal study. OBJECTIVE: The aim of this study was to evaluate an Artificial Intelligence (AI)-enabled ultrasound imaging system's ability to detect, segment, classify, and display neural and other structures during trans-psoas spine surgery. SUMMARY OF BACKGROUND DATA: Current methodologies for intraoperatively localizing and visualizing neural structures within the psoas are limited and can impact the safety of lateral lumbar interbody fusion (LLIF). Ultrasound technology, enhanced with AI-derived neural detection algorithms, could prove useful for this task. METHODS: The study was conducted using an in vivo porcine model (50 subjects). Image processing and machine learning algorithms were developed to detect neural and other anatomic structures within and adjacent to the psoas muscle while using an ultrasound imaging system during lateral lumbar spine surgery (SonoVision,™ Tissue Differentiation Intelligence, USA). The imaging system's ability to detect and classify the anatomic structures was assessed with subsequent tissue dissection. Dice coefficients were calculated to quantify the performance of the image segmentation. RESULTS: The AI-trained ultrasound system detected, segmented, classified, and displayed nerve, psoas muscle, and vertebral body surface with high sensitivity and specificity. The mean Dice coefficient score for each tissue type was >80%, indicating that the detected region and ground truth were >80% similar to each other. The mean specificity of nerve detection was 92%; for bone and muscle, it was >95%. The accuracy of nerve detection was >95%. CONCLUSION: This study demonstrates that a combination of AI-derived image processing and machine learning algorithms can be developed to enable real-time ultrasonic detection, segmentation, classification, and display of critical anatomic structures, including neural tissue, during spine surgery. AI-enhanced ultrasound imaging can provide a visual map of important anatomy in and adjacent to the psoas, thereby providing the surgeon with critical information intended to increase the safety of LLIF surgery.Level of Evidence: N/A.

The Association of "U.S. News & World Report" Hospital Rankings and Outcomes Following Anterior Cervical Fusions: Do Rankings Even Matter?

STUDY DESIGN: Retrospective observational study. OBJECTIVE: The aim of this study was to evaluate whether there are any differences in outcomes and costs for elective one- to three-level anterior cervical fusions (ACFs) performed at US News and World Report (USNWR) ranked and unranked hospitals. SUMMARY OF BACKGROUND DATA: Although the USNWR rankings are advertised by media and are routinely used by patients as a guide in seeking care, evidence regarding whether these rankings are reflective of actual clinical outcome remains limited. METHODS: The 2010-2014 USNWR hospital rankings were used to identify ranked hospitals in "Neurosurgery" and "Orthopedics." The 2010-2014 100% Medicare Standard Analytical Files (SAF100) were used to identify patients undergoing elective ACFs at ranked and unranked hospitals. Multivariable logistic regression and generalized linear regression analyses were used to assess for differences in 90-day outcomes and costs between ranked and unranked hospitals. RESULTS: A total of 110,520 patients undergoing elective one- to three-level ACFs were included in the study, of which 10,289 (9.3%) underwent surgery in one of the 100 ranked hospitals. Following multivariate analysis, there were no significant differences between ranked versus unranked hospitals with regards to wound complications (1.2% vs. 1.1%; P = 0.907), cardiac complications (12.9% vs. 11.9%; P = 0.055), pulmonary complications (3.7% vs. 6.7%; P = 0.654), urinary tract infections (7.3% vs. 5.8%; P = 0.120), sepsis (9.3% vs. 7.9%; P = 0.847), deep venous thrombosis (1.9% vs. 1.3%; P = 0.077), revision surgery (0.3% vs. 0.3%; P = 0.617), and all-cause readmissions (4.7% vs. 4.4%; P = 0.266). Ranked hospitals, as compared to unranked hospitals, had a slightly lower odds of experiencing renal complications (7.0% vs. 4.9%; P = 0.047), but had significantly higher risk-adjusted 90-day charges (+$17,053; P < 0.001) and costs (+ $1695; P < 0.001). CONCLUSION: Despite the higher charges and costs of care at ranked hospitals, these facilities appear to have similar outcomes as compared to unranked hospitals following elective ACFs.Level of Evidence: 3.

Use of Intraoperative CT Improves Accuracy of Spinal Navigation During Screw Fixation in Cervico-thoracic Region.

STUDY DESIGN: A retrospective analysis of a single-center consecutive series of patients. OBJECTIVE: To test the hypothesis that using a mobile intraoperative computed tomography in combination with spinal navigation would result in better accuracy of lateral mass and pedicle screws between C3 and T5 levels, compared to cone-beam computed tomography and traditional 2D fluoroscopy. SUMMARY OF BACKGROUND DATA: Use of spinal navigation associated with 3D imaging has been shown to improve accuracy of screw positioning in the cervico-thoracic region. However, use of iCT imaging compared to a cone-beam CT has not been fully investigated in these types of surgical interventions. METHODS: We retrospectively analyzed a series of patients who underwent posterior cervico-thoracic fixations using different intraoperative imaging systems in a single hospital. We identified three different groups of patients: Group A, operated under 2D-fluoroscopic guidance without navigation; Group B: O-arm guidance with navigation; Group C: iCT AIRO guidance with navigation. Primary outcome was the rate of accurately placed screws, measured on intra or postoperative CT scan with Neo et al. classification for cervical pedicles screws and Gertzbein et al. for thoracic pedicle screws. Screws in cervical lateral masses were evaluated according to a new classification created by the authors. RESULTS: Data on 67 patients and 495 screws were available. Overall screw accuracy was 92.8% (95.6% for lateral mass screws, 81.6% for cervical pedicle screws, and 90% for thoracic pedicle screws). Patients operated with iCT AIRO navigation had significantly fewer misplaced screws (2.4%) compared to 2D-fluoroscopic guidance (9.1%) and O-arm navigation (9.7%) (P = 0.0152). Accuracy rate of iCT navigation versus O-arm navigation was significantly higher (P = 0.0042), and there was no statistically significant difference in surgical time between the three Groups (P = 0.5390). CONCLUSION: Use of high-quality CT associated with spinal navigation significantly improved accuracy of screw positioning in the cervico-thoracic region.Level of Evidence: 3.

Biomechanical Evaluation of a Dynamic Stabilization System for the Prevention of Proximal Junctional Failure in Adult Deformity Surgery.

STUDY DESIGN: Biomechanical spine model. Comparison of stress in the implant and the adjacent cranial segment was done with conventional rigid versus dynamic stabilization system (DS) fixation. OBJECTIVE: The aim of this study was to study stress at the proximal end of spinal fixation with a novel DS. SUMMARY OF BACKGROUND DATA: High stress at the implant bone junction may cause proximal junctional failure (PJF) in adult deformity surgery. METHODS: Five life-size spine models were instrumented with pedicle screws and a 5.5-mm Titanium rod from T8-S1. The same models were subsequently instrumented with a similar rod and DS between T8-9 pedicle screws. The spine model was loaded with 25 Nm static load cranial to the proximal fixation in six directions. Strains were measured from the proximal screws. Disc pressure was measured from the proximal instrumented segment (T8-9) and cranial adjacent segment (T7-8). RESULTS: Rigid fixation produced highest strain at T8, followed by T10 then T9. In contrast, DS fixation produced highest strain at T10, followed by T9 then T8. Strain at T8 was significantly less with DS fixation than rigid fixation (P = 0.019). The T10 screw strain was not significantly higher with DS stabilization compared to rigid fixation (P = 0.091). Rigid fixation allowed no load-sharing or pressure rise at T8-9 but an abrupt rise at T7-8. DS system permitted load-sharing and pressure rise in T8-9; the difference compared to rigid fixation was significant in flexion loading (P = 0.04) and similar trend but not significant in extension (P = 0.09). DS system produced a rise in the adjacent segment disc pressure (T7-8), which was smaller than rigid fixation but not significant. CONCLUSION: Long spinal fixation using rigid rods produces maximum stress at the proximal end screw and increases adjacent disc pressure, possibly leading to PJF. Dynamic stabilization at the cranial end segment may prevent PJF by reducing these factors.Level of Evidence: N/A.

Load Sharing and Endplate Pressure Distribution in Anterior Interbody Fusion Influenced by Graft Choice.

BACKGROUND: Cage subsidence is a known complication of spinal fusion. Various aspects of cage design have been investigated for their influence on cage subsidence, whereas the potential contribution of graft material to load sharing is often overlooked. We aimed to determine whether graft in the aperture affects endplate pressure distribution. METHODS: The pressure distributions of a polyetheretherketone interbody cage with 3 different aperture graft conditions were evaluated: empty, demineralized bone matrix, and supercritical CO2-treated allograft bone crunch (SCCO2). RESULTS: Graft materials contributed as much as half the load transmission for SCCO2, whereas demineralized bone matrix contributed one third. Endplate areas in contact with the cage demonstrated decreased areas within the highest-pressure spectrum with SCCO2 graft materials compared with empty cages. CONCLUSIONS: Graft choice plays a role in reducing peak endplate pressures. This finding is relevant to implant subsidence, as well as graft loading and remodeling.

Sacroiliac joint fusion VS conservative management for chronic low back pain attributed to the sacroiliac joint: A protocol for systematic review and meta analysis.

INTRODUCTION: Low back pain (LBP) is high prevalent and it is the leading cause of years lived with disability in both developed and developing countries. The sacroiliac joint (SIJ) is a common reason that caused LBP. At present, the treatment of chronic LBP attributed to SIJ is mainly conservative treatment and surgical treatment. However, there are still controversies between the 2 treating methods, and there is no recognized standard of treatment or surgical indications. Recent publications indicated that minimally invasive sacroiliac joint arthrodesis was safe and more effective improving pain, disability, and quality of life compared with conservative management in 2 years follow-up, which re-raise the focus of sacroiliac joints fusion. This paper will systematically review the available evidence, comparing the effectiveness of sacroiliac joint fusion and conservative therapy for the treatment of gait retraining for patients suffered from LBP attributed to the sacroiliac joint. METHOD AND ANALYSIS: A systematic review and meta-analysis of relevant studies in Pubmed, Embase, SCOPUS, and Cochrane Library will be synthesized. Inclusion criteria will be studies evaluating clinical outcomes (i.e., changes to pain and/or function) comparing sacroiliac joint fusion and conservative therapy in populations sacroiliac join related LBP; studies with less than 10 participants in total will be excluded. The primary outcomes measured will be pain score, Oswestry Disability Index (ODI), and adverse events during treatment. Review Manager (Revman; Version 5.3) software will be used for data synthesis, sensitivity analysis, meta-regression, subgroup analysis, and risk of bias assessment. A funnel plot will be developed to evaluate reporting bias and Begg and Egger tests will be used to assess funnel plot symmetries. We will use the Grading of Recommendations Assessment, Development and Evaluation system to assess the quality of evidence. ETHICS AND DISSEMINATION: Our aim is to publish this systematic review and meta-analysis in a peer-reviewed journal. Our findings will provide information comparing the efficacy and safety comparing sacroiliac joint fusion and non-surgical treatment for patients with LBP attributed to the sacroiliac joint. This review will not require ethical approval as there are no issues about participant privacy.

PEEK versus titanium cages in lateral lumbar interbody fusion: a comparative analysis of subsidence.

OBJECTIVE: The authors have provided a review of radiographic subsidence after lateral lumbar interbody fusion (LLIF) as a comparative analysis between titanium and polyetheretherketone (PEEK) cages. Many authors describe a reluctance to use titanium cages in spinal fusion secondary to subsidence concerns due to the increased modulus of elasticity of metal cages. The authors intend for this report to provide observational data regarding the juxtaposition of these two materials in the LLIF domain. METHODS: A retrospective review of a prospectively maintained database identified 113 consecutive patients undergoing lateral fusion for degenerative indications from January to December 2017. The surgeons performing the cage implantations were two orthopedic spine surgeons and two neurosurgeons. Plain standing radiographs were obtained at 1-2 weeks, 8-12 weeks, and 12 months postoperatively. Using a validated grading system, interbody subsidence into the endplates was graded at these time points on a scale of 0 to III. The primary outcome measure was subsidence between the two groups. Secondary outcomes were analyzed as well. RESULTS: Of the 113 patients in the sample, groups receiving PEEK and titanium implants were closely matched at 57 and 56 patients, respectively. Cumulatively, 156 cages were inserted and recombinant human bone morphogenetic protein-2 (rhBMP-2) was used in 38.1%. The average patient age was 60.4 years and average follow-up was 75.1 weeks. Subsidence in the titanium group in this study was less common than in the PEEK cage group. At early follow-up, groups had similar subsidence outcomes. Statistical significance was reached at the 8- to 12-week and 52-week follow-ups, demonstrating more subsidence in the PEEK cage group than the titanium cage group. rhBMP-2 usage was also highly correlated with higher subsidence rates at all 3 follow-up time points. Age was correlated with higher subsidence rates in univariate and multivariate analysis. CONCLUSIONS: Titanium cages were associated with lower subsidence rates than PEEK cages in this investigation. Usage of rhBMP-2 was also robustly associated with higher endplate subsidence. Each additional year of age correlated with an increased subsidence risk. Subsidence in LLIF is likely a response to a myriad of factors that include but are certainly not limited to cage material. Hence, the avoidance of titanium interbody implants secondary solely to concerns over a modulus of elasticity likely overlooks other variables of equal or greater importance.

Comparision of biportal endoscopic and microscopic decompression in treatment of lumbar spinal stenosis: A comparative study protocol.

BACKGROUND: Microscopic bilateral decompression (MBD) has been suggested as an alternative to open laminectomy and fusion. Recently, percutaneous biportal endoscopic decompression (PBED) has begun to attract attention. The purpose of this retrospective study was to evaluate postoperative pain, functional disability, symptom reduction and satisfaction, and specific surgical parameters between the MBD and PBED techniques in patients with lumbar spinal stenosis (LSS). METHODS: A retrospective review of LSS patients performed with MBD or PBED technique between May 2015 and June 2018 was conducted. Institutional review board approval in People's Hospital of Ningxia Hui Nationality Autonomous Region was obtained prior to conducting chart review and analysis. We received informed consent from all patients before surgery. The primary outcomes assessed were the preoperative to postoperative changes in leg/back pain and disability/function, patient satisfaction with the procedure, and postoperative quality of life. The secondary outcomes including duration of postoperative hospital stay, time to mobilization, postoperative analgesic use, complication rates, and baseline patient characteristics were prospectively collected. RESULTS: The hypothesis was that the PBED technique would achieve better clinical outcomes as compared to the MBD technique in LSS.

Robot-Assisted Percutaneous Pedicle Screw Placement: Evaluation of Accuracy of the First 100 Screws and Comparison with Cohort of Fluoroscopy-guided Screws.

OBJECTIVE: Percutaneous pedicle screws (PPS) are used to stabilize the spine after interbody fusion in minimally invasive approaches. Recently, robotic assistance has been developed to improve the accuracy of PPS. We report our initial experience with ExcelsiusGPS and compare its accuracy with our historical cohort of fluoroscopy-guided PPS. METHODS: We reviewed prospectively collected data from our first 100 robot-assisted PPS. We graded accuracy of screws on computed tomography imaging and compared it with a previous cohort of 90 PPS placed using fluoroscopy. We also analyzed the effect of various demographic and perioperative metrics on accuracy. RESULTS: We placed 103 PPS in the first 20 consecutive patients with postoperative computed tomography imaging using ExcelsiusGPS. All screws were placed at L2 to S1. Our robot-assisted cohort had 6 breaches, with only 2 breaches >2 mm, yielding an overall breach rate of 5.8% and a significant breach rate of 1.9%. In comparison, our fluoroscopy-guided cohort had a breach rate of 3.3% and a significant breach rate of 1.1%, which was not significantly different. More breaches occurred in the first half of cases, suggesting a learning curve with robotic assistance. No demographic or perioperative metrics had a significant effect on accuracy. CONCLUSIONS: Our breach rates with ExcelsiusGPS were low and consistent with others reported in the literature, as well as with other robotic systems. Our series shows equivalent accuracy of placement of PPS with this robotic platform compared with fluoroscopic guidance and suggests a relatively short learning curve.

Comparison of Cranial Facet Joint Violation Rate and Four Other Clinical Indexes Between Robot-assisted and Freehand Pedicle Screw Placement in Spine Surgery: A Meta-analysis.

STUDY DESIGN: A meta-analysis. OBJECTIVE: Through meta-analysis, whether RA techniques are superior to conventional freehand (FH) techniques was determined in terms of cranial facet joint protection and four other clinical indexes, namely, the accuracy of pedicle screw placement, the number of surgical revision due to malposition, intraoperative radiation dose, and operative time. SUMMARY OF BACKGROUND DATA: Cranial facet joint violation (FJV) is an important risk factor for adjacent segment degeneration. Some studies recommended the use of robot-assisted (RA) pedicle screw placement in reducing the rate of cranial FJV instead of conventional FH pedicle screw placement. However, the superiority of RA techniques to FH techniques remains controversial. METHODS: A comprehensive search on PubMed, EMBASE, Cochrane, Web of Science, CNKI, and WanFang was conducted for the selection of potential eligible literature. The outcomes were evaluated in terms of odds ratio (OR) or standardized mean difference and corresponding 95% confidence interval (CI). The meta-analysis was conducted using RevMan 5.3. The subgroup analyses of the violation of the cranial facet joint and the accuracy of pedicle screw placement were performed on the basis of robot type. RESULT: Three randomized controlled trials, two prospective cohort study, and one retrospective cohort study consisting of 783 patients and 2694 cranial pedicle screws were included in the meta-analysis. RA pedicle screw placement was associated with significantly fewer cranial FJVs than FH screw placement. Subgroup analyses showed that the Renaissance (OR = 0.19, 95% CI = 0.07-0.56) and TINAVI (OR = 0.19, 95% CI = 0.09-0.38) robots under RA techniques were associated with significantly fewer cranial FJVs than FH techniques. Furthermore, the RA techniques showed more accurate pedicle screw placement and lower intraoperative radiation dose, equivalent number of surgical revision due to malposition, but longer operative time than the FH techniques. CONCLUSION: The RA (Renaissance and TINAVI) techniques are superior to conventional FH techniques in terms of protecting the cranial facet joint. RA techniques are accurate and safe in clinical application. LEVEL OF EVIDENCE: 2.

Outpatient Versus Inpatient Posterior Lumbar Fusion for Low-Risk Patients: An Analysis of Thirty-Day Outcomes From the National Surgical Quality Improvement Program.

BACKGROUND: Outpatient spine surgery has been increasingly used recently owing to its perceived cost benefits and its ability to offset the volume from the inpatient setting. However, the 30-day outcomes of outpatient posterior lumbar fusion (PLF) for low-risk patients have not been extensively studied. In the present study, we assessed the 30-day outcomes of outpatient PLF surgery for low-risk patients using a national surgical quality registry. METHODS: For the present study, we queried the American College of Surgeons National Surgical Quality Improvement Program for patients who had undergone PLF from 2009 to 2016. Only patients with an American Society of Anesthesiologists grade of 1-2 were included. The 30-day outcomes, including any complications, readmissions, and reoperations, were studied using multivariable logistic regression after adjustment for an array of patient-specific factors. RESULTS: A total of 29,830 cases were identified. Of these 29,830 cases, 1016 (3.4%) had been performed as outpatient cases and 28,814 (96.6%) as inpatient. After adjusting for an array of patient-specific factors, we did not find any significant association between the procedure setting and complication rate (odds ratio [OR], 0.8; 95% confidence interval [CI], 0.6-1.1; P = 0.15) or 30-day readmission rate (OR, 0.9; 95% CI, 0.6-1.4; P = 0.76). Patients undergoing outpatient PLF were more likely to have required a 30-day reoperation (OR, 1.6; 95% CI, 1.1-2.4; P = 0.02). CONCLUSION: Our results have demonstrated that the 30-day outcomes of patients who have undergone outpatient PLF might be comparable to those of patients who have undergone PLF in an inpatient setting. However, outpatient surgery might be associated with a greater overall reoperation rate.

In vitro comparison of personalized 3D printed versus standard expandable titanium vertebral body replacement implants in the mid-thoracic spine using entire rib cage specimens.

BACKGROUND: Expandable titanium implants have proven their suitability as vertebral body replacement device in several clinical and biomechanical studies. Potential stabilizing features of personalized 3D printed titanium devices, however, have never been explored. This in vitro study aimed to prove their equivalence regarding primary stability and three-dimensional motion behavior in the mid-thoracic spine including the entire rib cage. METHODS: Six fresh frozen human thoracic spine specimens with intact rib cages were loaded with pure moments of 5 Nm while performing optical motion tracking of all vertebrae. Following testing in intact condition (1), the specimens were tested after inserting personalized 3D printed titanium vertebral body replacement implants (2) and the two standard expandable titanium implants Obelisc™ (3) and Synex™ (4), each at T6 level combined with posterior pedicle screw-rod fixation from T4 to T8. FINDINGS: No significant differences (P < .05) in primary and secondary T1-T12 ranges of motion were found between the three implant types. Compared to the intact condition, slight decreases of the range of motion were found, which were significant for Synex™ in primary flexion/extension (-17%), specifically at T3-T4 level (-46%), primary lateral bending (-18%), and secondary lateral bending during primary axial rotation (-53%). Range of motion solely increased at T8-T9 level, while being significant only for Obelisc™ (+35%). INTERPRETATION: Personalized 3D printed vertebral body replacement implants provide a promising alternative to standard expandable devices regarding primary stability and three-dimensional motion behavior in the mid-thoracic spine due to the stabilizing effect of the rib cage.

[Comparison of the effectiveness of oblique lumbar interbody fusion and posterior lumbar interbody fusion for treatment of Cage dislodgement after lumbar surgery].

OBJECTIVE: To compare the clinical and radiological effectiveness of oblique lumbar interbody fusion (OLIF) and posterior lumbar interbody fusion (PLIF) in the treatment of Cage dislodgement after lumbar surgery. METHODS: The clinical data of 40 patients who underwent revision surgery due to Cage dislodgement after lumbar surgery betweem April 2013 and March 2017 were retrospectively analyzed. Among them, 18 patients underwent OLIF (OLIF group) and 22 patients underwent PLIF (PLIF group) for revision. There was no significant difference between the two groups in age, gender, body mass index, intervals between primary surgery and revision surgery, number of primary fused levels, disc spaces of Cage dislodgement, and visual analogue scale (VAS) scores of low back pain and leg pain, Oswestry disability index (ODI), the segmental lordosis (SL) and disc height (DH) of the disc space of Cage dislodgement, and the lumbar lordosis (LL) before revision ( P>0.05). The operation time, intraoperative blood loss, hospital stay, and complications of the two groups were recorded and compared. The VAS scores of low back pain and leg pain were evaluated at 3 days, 3, 6, and 12 months after operation, and the ODI scores were evaluated at 3, 6, and 12 months after operation. The SL and DH of the disc space of Cage dislodgement and LL were measured at 12 months after operation and compared with those before operation. CT examination was performed at 12 months after operation, and the fusion of the disc space implanted with new Cage was judged by Bridwell grading standard. RESULTS: The intraoperative blood loss in the OLIF group was significantly less than that in the PLIF group ( t=-12.425, P=0.000); there was no significant difference between the two groups in the operation time and hospital stay ( P>0.05). Both groups were followed up 12-30 months, with an average of 18 months. In the OLIF group, 2 patients (11.1%) had thigh numbness and 1 patient (5.6%) had hip flexor weakness after operation; 2 patients (9.1%) in the PLIF group had intraoperative dural sac tear. The other patients' incisions healed by first intention without early postoperative complications. There was no significant difference in the incidence of complications between the two groups ( χ 2=0.519, P=0.642). The VAS scores of low back pain and leg pain, and the ODI score of the two groups at each time point after operation were significantly improved when compared with those before operation ( P<0.05); there was no significant difference between the two groups at each time point after operation ( P>0.05). At 12 months after operation, SL, LL, and DH in the two groups were significantly increased when compared with preoperative ones ( P<0.05); SL and DH in the OLIF group were significantly improved when compared with those in the PLIF group ( P<0.05), and there was no significant difference in LL between the two groups ( P>0.05). CT examination at 12 months after operation showed that all the operated disc spaces achieved bony fusion. According to the Bridwell grading standard, 12 cases were grade Ⅰ and 6 cases were grade Ⅱ in the OLIF group, and 13 cases were grade Ⅰ and 9 cases were grade Ⅱ in the PLIF group; there was no significant difference between the two groups ( Z=-0.486, P=0.627). During follow-up, neither re-displacement or sinking of Cage, nor loosening or fracture of internal fixation occurred. CONCLUSION: OLIF and PLIF can achieve similar effectiveness in the treatment of Cage dislodgement after lumbar surgery. OLIF can further reduce intraoperative blood loss and restore the SL and DH of the disc space of Cage dislodgement better.

Enhanced Recovery after Lumbar Spine Fusion: A Randomized Controlled Trial to Assess the Quality of Patient Recovery.

BACKGROUND: Prospective trials of enhanced recovery after spine surgery are lacking. We tested the hypothesis that an enhanced recovery pathway improves quality of recovery after one- to two-level lumbar fusion. METHODS: A patient- and assessor-blinded trial of 56 patients randomized to enhanced recovery (17 evidence-based pre-, intra-, and postoperative care elements) or usual care was performed. The primary outcome was Quality of Recovery-40 score (40 to 200 points) at postoperative day 3. Twelve points defined the clinically important difference. Secondary outcomes included Quality of Recovery-40 at days 0 to 2, 14, and 56; time to oral intake and discharge from physical therapy; length of stay; numeric pain scores (0 to 10); opioid consumption (morphine equivalents); duration of intravenous patient-controlled analgesia use; complications; and markers of surgical stress (interleukin 6, cortisol, and C-reactive protein). RESULTS: The analysis included 25 enhanced recovery patients and 26 usual care patients. Significantly higher Quality of Recovery-40 scores were found in the enhanced recovery group at postoperative day 3 (179 ± 14 vs. 170 ± 16; P = 0.041) without reaching the clinically important difference. There were no significant differences in recovery scores at days 0 (175 ± 16 vs. 162 ± 22; P = 0.059), 1 (174 ± 18 vs. 164 ± 15; P = 0.050), 2 (174 ± 18 vs. 167 ± 17; P = 0.289), 14 (184 ± 13 vs. 180 ± 12; P = 0.500), and 56 (187 ± 14 vs. 190 ± 8; P = 0.801). In the enhanced recovery group, subscores on the Quality of Recovery-40 comfort dimension were higher (longitudinal mean score difference, 4; 95% CI, 1, 7; P = 0.008); time to oral intake (-3 h; 95% CI, -6, -0.5; P = 0.010); and duration of intravenous patient-controlled analgesia (-11 h; 95% CI, -19, -6; P < 0.001) were shorter; opioid consumption was lower at day 1 (-57 mg; 95% CI, -130, -5; P = 0.030) without adversely affecting pain scores (-2; 95% CI, -3, 0; P = 0.005); and C-reactive protein was lower at day 3 (6.1; 95% CI, 3.8, 15.7 vs. 15.9; 95% CI, 6.6, 19.7; P = 0.037). CONCLUSIONS: Statistically significant gains in early recovery were achieved by an enhanced recovery pathway. However, significant clinical impact was not demonstrated.

3-Dimensional printing templates guiding versus free hand technique for cervical lateral mass screw fixation: A prospective study.

OBJECTIVE: In this randomized, single blind and controlled study, the feasibility and precision of 3-dimensional printing templates for cervical lateral mass screw insertion was evaluated. METHODS: A total of 6 patients (72 screws), who were diagnosed with cervical spondylotic myelopathy (CSM) and developmental cervical spinal stenosis, were randomly divided into A and B two groups. All subjects underwent modified posterior surgery with using cervical lateral mass screws insertion (C4-C6). Group A underwent surgeries with screw insertion assisted by the guidance of 3-dimensional printing templates and Group B underwent surgeries with screw insertion by freehand. The criteria of the accuracy of screw placement were set as the main evaluation indicators. RESULTS: There was no significant difference between the 2 groups in age, improvement rate of JOA, operation time and blood loss. According to Bayard's criteria, 32 screws (88.9%) were described as "acceptable" in group A and 22 screws (61.1%) were described as "acceptable" in Group B (P < 0.05). Based on our criteria, the "excellent and good" rate of screws was 83.3% in group A and 47.2% in Group B, respectively (P < 0.05). The precision of screws' location in Group A was superior to that in Group B. CONCLUSIONS: 3-Dimensional printing screw insertion templates may achieve (1) comprehensive visualization of the cervical vertebrae and lateral mass and the individual surgical planning using the 3-dimensional model preoperatively. (2) increasing the accuracy of cervical lateral mass screw insertion.