Clinical effectiveness of reduction and fusion versus in situ fusion in the management of degenerative lumbar spondylolisthesis: a systematic review and meta-analysis.

PURPOSE: To compare the clinical effectiveness of reduction and fusion with in situ fusion in the management of patients with degenerative lumbar spondylolisthesis (DLS). METHODS: The systematic review was conducted following the PRISMA guidelines. Relevant studies were identified from PubMed, Embase, Scopus, Cochrane Library, ClinicalTrials.gov, and Google Scholar. The inclusion criteria were: (1) comparative studies of reduction and fusion versus in situ fusion for DLS patients, (2) outcomes reported as VAS/NRS, ODI, JOA score, operating time, blood loss, complication rate, fusion rate, or reoperation rate, (3) randomized controlled trials and observational studies published in English from the inception of the databases to January 2023. The exclusion criteria included: (1) reviews, case series, case reports, letters, and conference reports, (2) in vitro biomechanical studies and computational modeling studies, (3) no report on study outcomes. The risk of bias 2 (RoB2) tool and the Newcastle-Ottawa scale was conducted to assess the risk of bias of RCTs and observational studies, respectively. RESULTS: Five studies with a total of 704 patients were included (375 reduction and fusion, 329 in situ fusion). Operating time was significantly longer in the reduction and fusion group compared to in situ fusion group (weighted mean difference 7.20; 95% confidence interval 0.19, 14.21; P = 0.04). No additional significant intergroup differences were noted in terms of other outcomes analyzed. CONCLUSION: While the reduction and fusion group demonstrated a statistically longer operating time compared to the in situ fusion group, the clinical significance of this difference was minimal. The findings suggest no substantial superiority of lumbar fusion with reduction over without reduction for the management of DLS.

Good 5-year postoperative outcomes after facet fusion using a percutaneous pedicle screw system for degenerative lumbar spondylolisthesis.

Many authors have reported no significant differences in clinical outcomes between posterolateral fusion (PLF) and interbody fusion, as well as satisfactory long-term outcomes after PLF. Facet fusion (FF), a minimally invasive evolution of PLF, has also resulted in good clinical outcomes. This study aimed to assess the clinical outcomes 5 years after FF for degenerative lumbar spondylolisthesis (DLS) and determine whether good clinical outcomes were maintained after FF. Records of 115 patients who underwent FF for single-level DLS with at least 5 years of follow-up were retrospectively studied. The therapeutic effectiveness of FF was assessed as a clinical outcome using the Japanese Orthopaedic Association Back Pain Evaluation Questionnaire (JOABPEQ), the Roland-Morris Disability Questionnaire (RMDQ), and the visual analogue scale (VAS) preoperatively and at 1 and 5 years postoperatively. Computed tomography was performed for fusion confirmation. The revision surgery rate was also evaluated. The JOABPEQ category scores demonstrated therapeutic effectiveness in 81.7% of patients at 1 year postoperatively and 81.4% of patients at 5 years postoperatively for low back pain; the corresponding proportions for walking ability were 93.8% and 86.6%, respectively. There were no significant differences in therapeutic effectiveness at 1 and 5 years postoperatively for any category, including the RMDQ and VAS scores. The fusion rate was 90.4% at the final follow-up. Four patients required revision surgery for adjacent segment disease 1-5 years after the first surgery (revision surgery rate, 3.5%). Good clinical outcomes were maintained 5 years after FF, and FF had an extremely low revision surgery rate.

Hollow modular anchorage (HMA) screws for anterior transvertebral fixation in high-grade spondylolisthesis cases requiring 360 degrees in-situ fusion.

OBJECTIVE: 360 degrees in-situ fusion for high-grade spondylolisthesis showed satisfying clinical long-term results. Combining anterior with posterior surgery increases fusion rates. Anteriorly inserted transvertebral HMA screws could be an alternative to strut graft constructs or cages, avoiding donor site complications. In addition, complete posterior muscle detachment is avoided and the injury risk of neural structures is minimized. This study investigates the use of HMA screws in this context. MATERIAL AND METHODS: Five consecutive patients requiring L4-S1 in-situ fusion for isthmic spondylolisthesis (four Grade 3 and one Grade 4) were included. The L5/S1 level was fused with an HMA screw filled with local bone and bone morphogenic protein (BMP2), inserted via the L4/5 disc space level. An L4/5 stand-alone interbody fusion with additional minimal invasive posterior screw fixation was added. RESULTS: Transvertebral insertion of the HMA device was accomplished via a retroperitoneal approach to L4/L5 in all cases without exposure of L5/S1. Blood loss ranged from 150 ml-350 ml. No intraoperative complication occurred. One patient developed posterior wound infection requiring debridement. Solid fusion was confirmed with a CT scan after 6 months in all patients. All patients improved to unrestricted activities of daily living with two being limited by occasional back pain. CONCLUSIONS: HMA screws allow for effective lumbosacral fusion via a limited anterior exposure. This is technically easier than posterior exposure of the lumbosacral junction in high-grade spondylolisthesis requiring 360 degrees fusion.

Philosophies and Surgical Techniques for High-Grade Spondylolisthesis Treatment with Literature Review.

Introduction: High-grade spondylolisthesis is defined as cases with more than 50% displacement and spondylolisthesis with Meyerding grade III and higher. The surgical management of high-grade spondylolisthesis is highly controversial. Many surgical methods have been reported such as posterior in situ fusion, instrumented posterior fusion with or without reduction, combined anterior and posterior procedures, spondylectomy with reduction of L4 to the sacrum (for spondyloptosis), and posterior interbody fusion with trans-sacral fixation. The literature has recently mentioned minimally invasive transforaminal lumbar interbody fusion for high-grade spondylolisthesis. This study aimed to review the recent literature that describes the surgical outcomes associated with various surgical techniques used for high-grade spondylolisthesis. Materials and Methods: Recent articles were searched on search engines such as PubMed and Google Scholar using keywords such as "high-grade spondylolisthesis," "surgical techniques," and "complications." Discussion: The surgical management of high-grade spondylolisthesis is an area of significant controversy. The literature is replete with regards to the need for reduction, decompression, levels of fusion, the nature of instrumentation, surgical approaches including open, minimally invasive, and "mini-open" procedures, and various techniques for reducing the slip and fusion strategy. The three basic options of high-grade spondylolisthesis include in-situ fusion, partial reduction and fusion, and complete reduction. Conclusion: Various techniques have been described for high-grade spondylolisthesis. Spine deformity study group classification gives guidelines about balanced and unbalanced pelvis and advises reduction and fusion in case of unbalanced pelvis for correction of biomechanical and global sagittal alignment. Each of the surgical techniques has its advantages and disadvantages. However, individual authors' experience, skill levels, and anatomic reduction with fusion techniques have yielded encouraging results.

Comparison of facet fusion rates and clinical outcomes between cortical bone trajectory screw and percutaneous pedicle screw fixation for degenerative lumbar spondylolisthesis.

BACKGROUND CONTEXT: Cortical bone trajectory (CBT) screws have been introduced as an alternative technique for pedicle screw (PS) insertion because they have greater contact with the cortex and a greater uniaxial pullout load than traditional PS. CBT screwing can also minimize muscle dissection. However, CBT screws and traditional PSs have not yet been compared in terms of fusion rates and clinical outcomes for particular operative procedures. PURPOSE: This study aimed to assess the fusion rate and clinical outcomes of facet fusion (FF) fixed with CBT screws (CBT-FF) and to compare them with those of FF fixed with percutaneous PS (PPS-FF). STUDY DESIGN: Retrospective study. PATIENT SAMPLE: Records of 68 patients who underwent CBT-FF for single-level degenerative lumbar spondylolisthesis (DLS) with at least 1 year of follow-up were retrospectively reviewed. The control group comprised 143 patients who underwent PPS-FF under the same conditions. OUTCOME MEASURES: Computed tomography was performed to confirm fusion. Therapeutic effectiveness was assessed as a clinical outcome using the Japanese Orthopaedic Association Back Pain Evaluation Questionnaire (JOABPEQ), Roland-Morris Disability Questionnaire (RMDQ), and visual analog scale (VAS) preoperatively and 1 year postoperatively. The rate of revision surgery was also calculated. Intraoperative blood loss was measured. METHODS: Fusion rate, clinical outcomes, revision surgery rate, and intraoperative blood loss of CBT-FF and PPS-FF were compared. RESULTS: The CBT-FF and PPS-FF fusion rates were 91.2% and 90.1%, respectively. The JOABPEQ category scores demonstrated therapeutic effectiveness in 74.5% and 77.1% of the patients for low back pain; the corresponding proportions for walking ability were 84.7% and 89.3%, respectively. No significant differences in therapeutic effectiveness were observed for any category, including the RMDQ and VAS scores for buttock and lower limb pain. Three patients required revision surgery for adjacent segment disease between 6 months and 3.5 years after CBT-FF (revision surgery rate, 4.4%), whereas the revision surgery rate for PPS-FF was 6.3% (9/143 cases). Average intraoperative blood loss was significantly less in the CBT-FF group than in the PPS-FF group. CONCLUSIONS: Both procedures were equally useful in terms of fusion rate and clinical outcomes for DLS management.

Fusion with and without lever reduction in degenerative lumbar spondylolisthesis: a retrospective study.

BACKGROUND: The reduction of slipped vertebra is often performed during surgery for degenerative lumbar spondylolisthesis (DLS). This approach, while potentially improving clinical and radiological outcomes, also carries a risk of increased complications due to the reduction process. To address this, we introduced an innovative lever reduction technique for DLS treatment. This study aims to investigate the clinical efficacy, radiological outcomes, and complications of fusion with or without lever reduction. METHODS: We conducted a retrospective review of prospectively collected data from a registry of patients who underwent lumbar fusion surgery for DLS, with a follow-up of at least 24 months. Self-reported measures included visual analog scale (VAS) for back or leg pain, Oswestry Disability Index (ODI), and the achievement of minimal clinically important difference (MCID). Radiological assessments encompassed spondylolisthesis percentage (SP), focal lordosis (FL), and lumbar lordosis (LL). Complications were categorized using the modified Clavien-Dindo classification (MCDC) scheme. Patients were assigned to the reduction group (RG) and non-reduction group (NRG) based on the application of the lever reduction technique. Clinical and radiological outcomes at baseline, immediately after surgery, and at the last follow-up were compared. RESULTS: A total of 281 patients were analyzed (123 NRG, 158 RG). Baseline patient demographics, comorbidities, and surgical characteristics were similarly distributed between groups except for operating time (NRG 129.25 min, RG 138.04 min, P = .009). Both groups exhibited significant clinical improvement after surgery (all, P = .000), with no substantial difference between groups (VAS, ODI, or the ability to reach MCID). Patients in RG showed statistically lower SP and higher FL during follow-up (all, P = .000). LL was comparable at different time points within each group or at the same time point between the two groups (all, P > .050). The overall complication rate (NRG 38.2%, RG 27.2%, P = .050) or specific complication rates per MCDC were similar between groups (all, P > .050). Patients in RG were predisposed to a lower risk of adjacent segment degeneration (ASDeg) (NRG 9.8%, RG 6.3%, P = .035). CONCLUSIONS: There were no significant differences in postoperative measures such as VAS scores for back and leg pain, ODI, the ability to reach MCID, overall complication rate, or specific complication rates per MCDC between surgical approaches. However, fusion with lever reduction demonstrated a notable advantage in restoring segmental spinal sagittal alignment and reducing the occurrence of ASDeg compared to in situ fusion.

Various FDM Mechanisms Used in the Fabrication of Continuous-Fiber Reinforced Composites: A Review.

Fused Deposition Modeling (FDM) is an additive manufacturing technology that has emerged as a promising technique for fabricating 3D printed polymers. It has gained attention recently due to its ease of use, efficiency, low cost, and safety. However, 3D-printed FDM components lack sufficient strength compared to those made using conventional manufacturing methods. This low strength can be mainly attributed to high porosity and low sinterability of layers and then to the characteristics of the polymer used in the FDM process or the FDM process itself. Regarding polymer characteristics, there are two main types of reinforcing fibers: discontinuous (short) and continuous. Continuous-fiber reinforced composites are becoming popular in various industries due to their excellent mechanical properties. Since continuous reinforcing fibers have a more positive effect on increasing the strength of printed parts, this article focuses primarily on continuous long fibers. In addition to polymer characteristics, different mechanisms have been developed and introduced to address the issue of insufficient strength in 3D-printed FDM parts. This article comprehensively explains two main FDM mechanisms: in-situ fusion and ex-situ prepreg. It also provides relevant examples of these mechanisms using different reinforcing elements. Additionally, some other less frequently utilized mechanisms are discussed. Each mechanism has its own advantages and disadvantages, indicating that further development and modification are needed to increase the strength of 3D-printed FDM parts to be comparable to those produced using traditional methods.

Clinical appearance and reliability in visual assessment after in situ fusion for high-grade isthmic spondylolisthesis.

PURPOSE: The current literature on clinical appearance after surgery for high-grade spondylolisthesis is inconclusive. The few long-term comparative studies on surgical reduction versus in situ fusion report contradictory findings concerning appearance-related issues. The purpose of the current study was to evaluate and quantify clinical appearance three decades after in situ fusion for high-grade isthmic spondylolisthesis. METHODS: The Scoliosis Research Society (SRS)-22r questionnaire, digital photographs and standing lateral radiographs were used to evaluate clinical appearance for 22 patients three decades after in situ fusion for high-grade spondylolisthesis. The appearance was assessed by two spine surgeons, by the patient themselves, and by quantification of cosmesis relevant radiographic variables including pelvic parameters and sagittal balance. RESULTS: The surgeon inter- and intraobserver reliability of the photographic evaluation of the trunk deformity was at most moderate (Cohen's kappa 0.5). Correlation analysis revealed at most medium correlation between radiographic outcome and self-rated (SRS-22r) self-image (Spearman's rank correlation coefficient 0.3). The agreement between patient and surgeon-rated trunk appearance was poor (Cohen's kappa 0.2). CONCLUSIONS: Photographic evaluation of the trunk deformity in high-grade spondylolisthesis is unreliable. There were only weak correlations between patient self-assessed trunk appearance and radiographic parameters. The results reflect the pronounced subjectivity of cosmesis, and that the trunk deformity in high-grade spondylolisthesis is not easily observed. LEVEL OF EVIDENCE: IV.

Reduction versus In Situ Fusion for Adult High-Grade Spondylolisthesis: A Systematic Review and Meta-Analysis.

BACKGROUND: Surgical management of high-grade spondylolisthesis is controversial. Both reduction and in situ fusion are available options, but it remains unclear which approach provides better outcomes. We conducted a systematic review and meta-analysis of studies reporting outcomes following reduction or in situ fusion for adult high-grade spondylolisthesis. METHODS: PubMed, Embase, Web of Science, and Cochrane databases were last searched on June 24, 2019. We identified 1236 studies after excluding duplicates. After screening, 15 studies were included in the meta-analysis. Random-effects models were used to pool effect estimates. RESULTS: A total of 188 patients were analyzed. Compared with reduction, in situ fusion had a higher mean estimated blood loss (584 mL vs. 451 mL) and a clinically higher incidence of neurologic (48% vs. 15%), pseudarthrosis (13% vs. 8%), and infectious (20% vs. 10%) complications; however, these differences were not statistically significant. Reduction was associated with a clinically higher incidence of overall complications (32% vs. 25%) and dural tears (22% vs. 7%). Reduction provided better pain relief (mean difference [MD] = 5.24 vs. 4.77) and greater change in pelvic tilt (MD = 5.33 vs. 2.60); however, these differences were not statistically significant. Patients who underwent reduction had significantly greater decline in Oswestry Disability Index scores (MD = 55.7 vs. 11.5; Pinteraction < 0.01) and greater change in slip angle (MD = 25.0 vs. 11.4; Pinteraction = 0.01). CONCLUSIONS: In management of adult high-grade spondylolisthesis, both approaches appeared to be safe and effective. Reduction appeared to offer better disability relief and spinopelvic parameter correction than in situ fusion.

Rollback Imaging as a Useful Tool in the Preoperative Evaluation of Osteoporotic Vertebral Fractures.

INTRODUCTION: When surgery is performed for osteoporotic vertebral fractures, the extent to which kyphosis can be corrected by the intraoperative position of the body is often determined by preoperative radiography in the extension position. However, patients have difficulty adopting an adequate extension position due to the pain associated with their vertebral fracture. We place a pillow beneath the fractured vertebral body before surgery and take radiographs in the supine position to evaluate the extent to which the kyphosis can be corrected. This study aimed to examine the usefulness of this imaging method by comparing postoperative radiographs with preoperative radiographs taken with a pillow placed beneath the fractured vertebral body. METHODS: Lateral preoperative radiographs were taken of the patients in seated flexion and extension positions and the supine position. Lateral radiographs (rollback) were also taken 5 min after placing a firm pillow 20 cm in diameter beneath the fractured vertebral body. The kyphotic angle was compared between preoperative lateral radiographs of patients in the flexion, extension, and supine positions, rollback, and postoperative lateral radiographs in the supine position. RESULTS: The mean kyphotic angle was 33.3° in the flexion position, 28.3° in the extension position, 14.8° in the supine position, and 5.6° in rollback preoperatively and 6.4° postoperatively. The preoperative kyphotic angle differed from the postoperative kyphotic angle by ≥11° in 91% and 83% of participants in the flexion and extension positions, respectively; the difference was ≤ 5° in 30% and 61% of participants in the supine position and rollback, respectively. Differences in the postoperative angle were small in the order of rollback, supine position, extension position, and flexion position. CONCLUSIONS: Compared with radiographs taken in the flexion, extension, and supine positions, rollback showed little difference from postoperative radiographs, which showed almost the same angle as the intraoperative kyphotic angle.

The impact of surgical reduction of high-grade lumbosacral spondylolisthesis on proximal femoral angle and quality of life.

BACKGOUND CONTEXT: Abnormal proximal femoral angle (PFA) was recently found to be associated with deteriorating sagittal balance and quality of life (QoL) in high-grade spondylolisthesis (HGS). However, the influence of PFA on the QoL of patients undergoing surgery remains unknown. PURPOSE: This study compares the pre- and postoperative measurements of sagittal balance including PFA in patients with lumbosacral HGS after surgery. It also determines if PFA is a radiographic parameter that is associated with QoL in patients undergoing surgery. STUDY DESIGN: Retrospective cohort study. PATIENT SAMPLE: Thirty-three patients (mean age 15.6 ± 3.0 years) operated for L5-S1 HGS between July 2002 and April 2015. Thirteen had in situ fusion and 20 had reduction to a low-grade slip. OUTCOME MEASURES: The outcome measures included PFA and QoL scores measured from the Scoliosis Research Society SRS-30 QoL questionnaire. METHODS: The minimum follow-up was 2 years. PFA and QoL were compared pre- and postoperatively. Statistical analysis used nonparametric Mann-Whitney and Wilcoxon Signed Rank tests, Chi-square tests to compare proportions, and bivariate correlations with Spearman's coefficients. RESULTS: A decreasing PFA correlated with less pain (r = -0.56, p = .010), improved function (r = -0.51, p = .022) and better self-image (r = -0.46, p = .044) postreduction. Reduction decreased PFA by 5.1° (p = .002), whereas in situ fusion did not alter PFA significantly. Patients with normal preoperative PFA had similar postoperative QoL regardless of the type of surgery, except for self-image, which improved further with reduction (3.73 ± 0.49 to 4.26 ± 0.58, p = .015). Patients with abnormal preoperative PFA tended to have a higher QoL in all domains after reduction. CONCLUSION: Decreasing PFA correlates with less pain, better function and self-image. Reduction of HGS decreases PFA. Reduction also relates to a better postoperative QoL when the preoperative PFA is abnormal. When the preoperative PFA is normal, in situ fusion is equivalent to reduction except for self-image, which is better improved after reduction.

[Spondylolysis and spondylolisthesis in children and adolescents]. / Espondilolisis y espondilolistesis en niños y adolescentes.

Low back pain is a common cause of lost playing time in young athletes, and spondylolysis is its most common identifiable cause. Despite technological advances in radiology, which can lead to an early diagnosis with better prognosis, progression to spondylolisthesis is sometimes asymptomatic and may not be detected until late stages. There are wide variations, suggesting lack of consensus as regards the objective of treatment, which consists of clinical, radiological, biomechanical or functional improvement. There is also a lack of agreement regarding the ideal conservative treatment, surgical indications and need of slip reduction, and most of the established recommendations are not evidence based. We present a review of literature, which summarizes the current knowledge of spondylolysis and spondylolisthesis in children and adolescents.