Pseudarthrosis risk factors in lumbar fusion: a systematic review and meta-analysis.

This study presents a systematic literature review and meta-analysis of pseudarthrosis risk factors following lumbar fusion procedures. The odds ratio (OR) and 95% confidence interval (95% CI) were used for outcome measurements. The objective of this study was to identify the independent risk factors for pseudarthrosis after lumbar spinal fusion, which is crucial for mitigating morbidity and reoperation. Systematic searches in PubMed, Embase, and Scopus (1990-July 2021) were conducted using specific terms. The inclusion criteria included prospective and retrospective cohorts and case‒control series reporting ORs with 95% CIs from multivariate analysis. The quality assessment utilized the Newcastle-Ottawa scale. Meta-analysis, employing OR and 95% CI, assessed pseudarthrosis risk factors in lumbar fusion surgery, depicted in a forest plot. Of the 568 abstracts identified, 12 met the inclusion criteria (9 retrospective, 2006-2021). The 17 risk factors were categorized into clinical, radiographic, surgical, and bone turnover marker factors. The meta-analysis highlighted two significant clinical risk factors: age (95% CI 1.02-1.11; p = 0.005) and smoking (95% CI 1.68-5.44; p = 0.0002). The sole significant surgical risk factor was the number of fused levels (pooled OR 1.35; 95% CI 1.17-1.55; p < 0.0001). This study identified 17 risk factors for pseudarthrosis after lumbar fusion surgery, emphasizing age, smoking status, and the number of fusion levels. Prospective studies are warranted to explore additional risk factors and assess the impact of surgery and graft type.

Unilateral biportal endoscopic versus microscopic transforaminal lumbar interbody fusion for lumbar degenerative disease: a retrospective study.

BACKGROUND: In the past decade, Minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) with a microscopic tubular technique has become a surgical procedure that reduces surgical-related morbidity, shortens hospital stays, and expedites early rehabilitation in the treatment of lumbar degenerative diseases (LDD). Unilateral biportal endoscopic transforaminal lumbar interbody fusion (Endo-TLIF) has emerged as a novel surgical technique. The present study aims to compare the clinical outcomes and postoperative complications of MIS-TLIF and Endo-TLIF for treating LDD. METHODS: A retrospective analysis of LLD patients undergoing either Endo-TLIF or MIS-TLIF was performed. Patient demographics, operative data (operation time, estimated blood loss, length of hospitalization), and complications were recorded. The visual analog scale (VAS) score for leg and back pain and the Oswestry Disability Index (ODI) score were used to evaluate the clinical outcomes. RESULTS: This study involved 80 patients, 56 in the MIS-TLIF group and 34 in the Endo-TLIF group. The Endo-TLIF group showed a more substantial improvement in the VAS for back pain at 3 weeks post-surgery compared to the MIS-TLIF group. However, at the 1-year mark after surgery, there were no significant differences between the groups in the mean VAS for back pain and VAS for leg pain. Interestingly, the ODI at one year demonstrated a significant improvement in the Endo-TLIF group compared to the MIS-TLIF group. Additionally, the MIS-TLIF group exhibited a shorter operative time than the Endo-TLIF group, with no notable differences in estimated blood loss, length of hospitalization, and complications between the two groups. CONCLUSION: Endo-TLIF and MIS-TLIF are both safe and effective for LDD. In surgical decision-making, clinicians may consider nuances revealed in this study, such as lower early postoperative back pain with Endo-TLIF and shorter operative time with MIS-TLIF.

Spine Surgery in a Geriatric Population. Is it Really Different?

OBJECTIVES: Spinal degenerative disorders are a major cause of morbidity in the elderly resulting in high dependency. Most of them have a trend to be managed conservatively considering age, comorbidities, and apprehensions of surgical complications. Surgical intervention at early stage with appropriate indications can have better outcomes rather than conservative management in fit patients. The objective of the study is to evaluate the functional outcome in geriatric patients > 60 years who have undergone various spinal procedures for degenerative spine. METHODS: The study is retrospective, which includes all cases of spinal degenerative disease operated between 2014 and 2016. They were divided into geriatric (>60 years) and non-geriatric cohorts. These include all patients undergoing spinal decompression and/or instrumentation for degenerative disorders of the spine. Patients were interviewed for their functional outcomes in the follow-up period. RESULTS: A total of 184 spine cases were operated upon by a single surgeon, out of which a total of 139 cases were operated for the spinal degenerative condition. Forty-eight patients underwent lumbar spinal fusion procedures, 67 underwent non-instrumented lumbar decompression, and 24 patients underwent cervical procedures. These were further divided into 65 geriatric cases and 74 non-geriatric cases. The outcome was assessed with improvement and functional outcomes for spinal disability. Statistical analysis was performed using SPSS 20. CONCLUSION: It is concluded that surgical intervention for spinal problems in geriatric patients is not different from the general population. The outcome is also satisfactory provided, the choice of surgical procedure as per its indication is appropriate. The usual preoperative evaluation for the geriatric age group is very important. The performance status before surgery and the comorbidities have a direct bearing on the outcome in these patients.

Enhancing spinal bone anchor pull-out resistance with an L-shaped anchor.

The success rate of spinal fusion surgery is mainly determined by the fixation strength of the spinal bone anchors. This study explores the use of an L-shaped spinal bone anchor that is intended to establish a macro-shape lock with the posterior cortical layer of the vertebral body, thereby increasing the pull-out resistance of the anchor. The performance of this L-shaped anchor was evaluated in lumbar vertebra phantoms (L1-L5) across four distinct perpendicular orientations (lateral, medial, superior, and inferior). During the pull-out experiments, the pull-out force, and the displacement of the anchor with respect to the vertebra was measured which allowed the determination of the maximal pull-out force (mean: 123 N ± 25 N) and the initial pull-out force, the initial force required to start motion of the anchor (mean: 23 N ± 16 N). Notably, the maximum pull-out force was observed when the anchor engaged the cortical bone layer. The results demonstrate the potential benefits of utilising a spinal bone anchor featuring a macro-shape lock with the cortical bone layer to increase the pull-out force. Combining the macro shape-lock fixation method with the conventional pedicle screw shows the potential to significantly enhance the fixation strength of spinal bone anchors.

Long-term efficacy of Waveflex semi-rigid-dynamic-internal-fixation system in delaying intervertebral disc degeneration at adjacent segments and improving spinal sagittal imbalance.

The Waveflex semi-rigid-dynamic-internal-fixation system shows good short-term effects in the treatment of lumbar degenerative diseases, but there are few long-term follow-up studies, especially for recovery of sagittal balance. Fifty patients with lumbar degenerative diseases treated from January 2016 to October 2017 were retrospectively analysed: 25 patients treated with Waveflex semi-rigid-dynamic-internal-fixation system (Waveflex group) and 25 patients treated with double-segment PLIF (PLIF group). Clinical efficacy was evaluated by Visual Analogue Scale (VAS) and Oswestry Disability Index (ODI). Imaging data before surgery and at 3 months, 1 year, and 5 years postoperatively was used for imaging indicator assessment. Local disc degeneration of the cephalic adjacent segment (including disc height index (DHI), intervertebral foramen height (IFH), and range of motion (ROM)) and overall spinal motor function (including lumbar lordosis (LL), pelvic incidence (PI), sacral slope (SS), pelvic tilt (PT), and |PI-LL|) were analysed. Regarding clinical efficacy, comparison of VAS and ODI scores between the Waveflex and PLIF groups showed no significant preoperative or postoperative differences. The comparison of the objective imaging indicators showed no significant differences in the DHI, IFH, LL, |PI-LL|, and SS values between the Waveflex and PLIF groups preoperatively and 3 months postoperatively (P > 0.05). These values were significantly different at 1 and 5 years postoperatively (P < 0.05), and the Waveflex group showed better ROM values than those of the PLIF group (P < 0.05). PI values were not significantly different between the groups, but PT showed a significant improvement in the Waveflex group 5 years postoperatively (P < 0.05). The Waveflex semi-rigid dynamic fixation system can effectively reduce the probability of intervertebral disc degeneration in upper adjacent segments. Simultaneously, patients in the Waveflex group showed postoperative improvements in LL, spinal sagittal imbalance, and quality of life.

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).

Precise execution of personalized surgical planning using three-dimensional printed guide template in severe and complex adult spinal deformity patients requiring three-column osteotomy: a retrospective, comparative matched-cohort study.

BACKGROUND: The surgical treatment of severe and complex adult spinal deformity (ASD) commonly required three-column osteotomy (3-CO), which was technically demanding with high risk of neurological deficit. Personalized three dimensional (3D)-printed guide template based on preoperative planning has been gradually applied in 3-CO procedure. The purpose of this study was to compare the efficacy, safety, and precision of 3D-printed osteotomy guide template and free-hand technique in the treatment of severe and complex ASD patients requiring 3-CO. METHODS: This was a single-centre retrospective comparative cohort study of patients with severe and complex ASD (Cobb angle of scoliosis > 80° with flexibility < 25% or focal kyphosis > 90°) who underwent posterior spinal fusion and 3-CO between January 2020 to January 2023, with a minimum 12 months follow-up. Personalized computer-assisted three-dimensional osteotomy simulation was performed for all recruited patients, who were further divided into template and non-template groups based on the application of 3D-printed osteotomy guide template according to the surgical planning. Patients in the two groups were age- and gender- propensity-matched. The radiographic parameters, postoperative neurological deficit, and precision of osteotomy execution were compared between groups. RESULTS: A total of 40 patients (age 36.53 ± 11.98 years) were retrospectively recruited, with 20 patients in each group. The preoperative focal kyphosis (FK) was 92.72° ± 36.77° in the template group and 93.47° ± 33.91° in the non-template group, with a main curve Cobb angle of 63.35° (15.00°, 92.25°) and 64.00° (20.25°, 99.20°), respectively. Following the correction surgery, there were no significant differences in postoperative FK, postoperative main curve Cobb angle, correction rate of FK (54.20% vs. 51.94%, P = 0.738), and correction rate of main curve Cobb angle (72.41% vs. 61.33%, P = 0.101) between the groups. However, the match ratio of execution to simulation osteotomy angle was significantly greater in the template group than the non-template group (coronal: 89.90% vs. 74.50%, P < 0.001; sagittal: 90.45% vs. 80.35%, P < 0.001). The operating time (ORT) was significantly shorter (359.25 ± 57.79 min vs. 398.90 ± 59.48 min, P = 0.039) and the incidence of postoperative neurological deficit (5.0% vs. 35.0%, P = 0.018) was significantly lower in the template group than the non-template group. CONCLUSION: Performing 3-CO with the assistance of personalized 3D-printed guide template could increase the precision of execution, decrease the risk of postoperative neurological deficit, and shorten the ORT in the correction surgery for severe and complex ASD. The personalized osteotomy guide had the advantages of 3D insight of the case-specific anatomy, identification of osteotomy location, and translation of the surgical planning or simulation to the real surgical site.

Transiliac-Shortening Osteotomy to Treat Ischial Pressure Injury due to Fixed Pelvic Obliquity: A Case Report.

CASE: A 17-year-old adolescent boy with Gross Motor Function Classification System 5 cerebral palsy and neuromuscular scoliosis underwent posterior spinal fusion and segmental spinal instrumentation from T3 to the pelvis. He developed a right ischial pressure injury a few months postoperatively, which persisted despite nonoperative measures. He subsequently underwent an ipsilateral transiliac-shortening osteotomy 16 months after spinal surgery to treat his residual pelvic obliquity and the ischial pressure injury, which healed completely. At the 1-year follow-up visit, there were no further signs of pressure injury. CONCLUSION: This case report describes transiliac-shortening osteotomy as a viable treatment option for non-healing ischial pressure injuries secondary to fixed pelvic obliquity.

Comparison of minimally invasive transforaminal lumbar interbody fusion and midline lumbar interbody fusion in patients with spondylolisthesis.

BACKGROUND: This study aimed to compare surgical outcomes, clinical outcomes, and complications between minimally invasive transforaminal lumbar interbody fusion (MIS TLIF) and midline lumbar interbody fusion (MIDLIF) in patients with spondylolisthesis. METHODS: This study retrospectively compared the patients who underwent MIS TLIF (n = 37) or MIDLIF (n = 50) for spinal spondylolisthesis. Data of surgical outcomes (postoperative one-year fusion rate and time to bony fusion), clinical outcomes (visual analog scale [VAS] for pain and Oswestry Disability Index [ODI] for spine function), and complications were collected and analyzed. RESULTS: There was more 2-level fusion in MIDLIF (46% vs. 24.3%, p = 0.038). The MIS TLIF and MIDLIF groups had similar one-year fusion rate and time to fusion. The MIDLIF group had significantly lower VAS at postoperative 3-months (2.2 vs. 3.1, p = 0.002) and postoperative 1-year (1.1 vs. 2.1, p = < 0.001). ODI was not significantly different. The operation time was shorter in MIDLIF (166.1 min vs. 196.2 min, p = 0.014). The facet joint violation is higher in MIS TLIF (21.6% vs. 2%, p = 0.009). The other complications were not significantly different including rate of implant removal, revision, and adjacent segment disease. CONCLUSION: In this study, postoperative VAS, operation time, and the rate of facet joint violation were significantly higher in the MIS TLIF group. Comparable outcomes were observed between MIDLIF and MIS TLIF in terms of fusion rate, time to fusion, and postoperative ODI score.

Mesenchymal Stem Cell Exosomes Enhance Posterolateral Spinal Fusion in a Rat Model.

Spinal fusion, a common surgery performed for degenerative lumbar conditions, often uses recombinant human bone morphogenetic protein 2 (rhBMP-2) that is associated with adverse effects. Mesenchymal stromal/stem cells (MSCs) and their extracellular vesicles (EVs), particularly exosomes, have demonstrated efficacy in bone and cartilage repair. However, the efficacy of MSC exosomes in spinal fusion remains to be ascertained. This study investigates the fusion efficacy of MSC exosomes delivered via an absorbable collagen sponge packed in a poly Ɛ-caprolactone tricalcium phosphate (PCL-TCP) scaffold in a rat posterolateral spinal fusion model. Herein, it is shown that a single implantation of exosome-supplemented collagen sponge packed in PCL-TCP scaffold enhanced spinal fusion and improved mechanical stability by inducing bone formation and bridging between the transverse processes, as evidenced by significant improvements in fusion score and rate, bone structural parameters, histology, stiffness, and range of motion. This study demonstrates for the first time that MSC exosomes promote bone formation to enhance spinal fusion and mechanical stability in a rat model, supporting its translational potential for application in spinal fusion.

The effect of preoperative use of anticoagulants on the hemostatic effect of intravenous application of tranexamic acid in PLIF: a case control study.

Intravenous application of tranexamic acid (TXA) in posterior lumbar interbody fusion (PLIF) can effectively reduce blood loss without affecting coagulation function. However, it has not been reported whether preoperative use of anticoagulants may affect the efficacy of TXA in PLIF. The purpose of this study is to observe the effect of preoperative use of anticoagulants on coagulation indicators and blood loss after PLIF receiving intravenous unit dose TXA. A retrospective analysis was conducted on data from 53 patients with PLIF between 2020.11 and 2022.9, who received intravenous application of a unit dose of TXA (1 g/100 mL) 15 min before the skin incision after general anesthesia. Those who used anticoagulants within one week before surgery were recorded as the observation group, while those who did not use anticoagulants were recorded as the control group. The main observation indicators include surgical time, intraoperative blood loss, postoperative drainage volume, blood transfusion, and red blood cell (RBC), hemoglobin (HB), and hematocrit (HCT) measured on the 1st, 4th, 7th, and last-test postoperative days. Secondary observation indicators included postoperative incision healing, deep vein thrombosis of lower limbs, postoperative hospital stay, and activated partial thrombin time (APTT), prothrombin time (PT), thrombin time (TT), fibrinogen (FIB), and platelets (PLT) on the 1st and 4th days after surgery. The operation was successfully completed in both groups, the incision healed well after operation, and no lower limb deep vein thrombosis occurred. There was no significant difference in surgical time, intraoperative blood loss, postoperative drainage volume, and blood transfusion between the two groups (p > 0.05). There was no significant difference in the RBC, HB, and HCT measured on the 1st, 4th, 7th, and last-test postoperative days between the two groups (p > 0.05). There was no statistically significant difference in APTT, PT, TT, FIB and PLT between the two groups on the 1st and 4th postoperative days (p > 0.05). There was no significant difference in postoperative hospital stay between the two groups (p > 0.05). The use of anticoagulants within one week before surgery does not affect the hemostatic effect of intravenous unit dose TXA in PLIF.

[Prospective comparative study of unilateral biportal endoscopic transforaminal lumbar interbody fusion and endoscopic transforaminal lumbar interbody fusion for treatment of single-segment degenerative lumbar spinal stenosis with lumbar spondylolisthesis].

Objective: To compare the effectiveness of unilateral biportal endoscopic transforaminal lumbar interbody fusion (UBE-TLIF) and endoscopic transforaminal lumbar interbody fusion (Endo-TLIF) in the treatment of single-segment degenerative lumbar spinal stenosis with lumbar spondylolisthesis. Methods: Between November 2019 and May 2023, a total of 81 patients with single-segment degenerative lumbar spinal stenosis with lumbar spondylolisthesis who met the selection criteria were enrolled. They were randomly divided into UBE-TLIF group (39 cases) and Endo-TLIF group (42 cases). There was no significant difference in baseline data between the two groups ( P>0.05), including gender, age, body mass index, surgical segment, and preoperative visual analogue scale (VAS) scores for low back and leg pain, Oswestry Disability Index (ODI), and serum markers including creatine kinase (CK) and C reactive protein (CRP). Total blood loss (TBL), intraoperative blood loss, hidden blood loss (HBL), postoperative drainage volume, and operation time were recorded and compared between the two groups. Serum markers (CK, CRP) levels were compared between the two groups at 1 day before operation and 1, 3, and 5 days after operation. Furthermore, the VAS scores for low back and leg pain, and ODI at 1 day before operation and 1 day, 3 months, 6 months, and 12 months after operation, and intervertebral fusion rate at 12 months after operation were compared between the two groups. Results: All surgeries were completed successfully without occurrence of incision infection, vascular or nerve injury, epidural hematoma, dural tear, or postoperative paraplegia. The operation time in UBE-TLIF group was significantly shorter than that in Endo-TLIF group, but the intraoperative blood loss, TBL, and HBL in UBE-TLIF group were significantly more than those in Endo-TLIF group ( P<0.05). There was no significant difference in postoperative drainage volume between the two groups ( P>0.05). The levels of CK at 1 day and 3 days after operation and CRP at 1, 3, and 5 days after operation in UBE-TLIF group were slightly higher than those in the Endo-TLIF group ( P<0.05), while there was no significant difference in the levels of CK and CPR between the two groups at other time points ( P>0.05). All patients were followed up 12 months. VAS score of low back and leg pain and ODI at each time point after operation significantly improved when compared with those before operation in the two groups ( P<0.05); there was no significant difference in VAS score of low back and leg pain and ODI between the two groups at each time point after operation ( P>0.05). There was no significant difference in the intervertebral fusion rate between the two groups at 12 months after operation ( P>0.05). Conclusion: UBE-TLIF and Endo-TLIF are both effective methods for treating degenerative lumbar spinal stenosis with lumbar spondylolisthesis. However, compared to Endo-TLIF, UBE-TLIF requires further improvement in minimally invasive techniques to reduce tissue trauma and blood loss.

[Application of self-stabilizing zero-profile three-dimensional printed artificial vertebral bodies for treatment of cervical spondylotic myelopathy].

Objective: To evaluate the safety and effectiveness of applying self-stabilizing zero-profile three-dimensional (3D) printed artificial vertebral bodies in anterior cervical corpectomy and fusion (ACCF) for cervical spondylotic myelopathy. Methods: A retrospective analysis was conducted on 37 patients diagnosed with cervical spondylotic myelopathy who underwent single-level ACCF using either self-stabilizing zero-profile 3D-printed artificial vertebral bodies ( n=15, treatment group) or conventional 3D-printed artificial vertebral bodies with titanium plates ( n=22, control group) between January 2022 and February 2023. There was no significant difference in age, gender, lesion segment, disease duration, and preoperative Japanese Orthopedic Association (JOA) score between the two groups ( P>0.05). Operation time, intraoperative bleeding volume, hospitalization costs, JOA score and improvement rate, incidence of postoperative prosthesis subsidence, and interbody fusion were recorded and compared between the two groups. Results: Compared with the control group, the treatment group had significantly shorter operation time and lower hospitalization costs ( P<0.05); there was no significant difference in intraoperative bleeding volume between the two groups ( P>0.05). All patients were followed up, with a follow-up period of 6-21 months in the treatment group (mean, 13.7 months) and 6-19 months in the control group (mean, 12.7 months). No dysphagia occurred in the treatment group, while 5 cases occurred in the control group, with a significant difference in the incidence of dysphagia between the two groups ( P<0.05). At 12 months after operation, both groups showed improvement in JOA scores compared to preoperative scores, with significant differences ( P<0.05); however, there was no significant difference in the JOA scores and improvement rate between the two groups ( P>0.05). Radiographic examinations showed the interbody fusion in both groups, and the difference in the time of interbody fusion was not significant ( P>0.05). At last follow-up, 2 cases in the treatment group and 3 cases in the control group experienced prosthesis subsidence, with no significant difference in the incidence of prosthesis subsidence ( P>0.05). There was no implant displacement or plate-screw fracture during follow-up. Conclusion: The use of self-stabilizing zero-profile 3D-printed artificial vertebral bodies in the treatment of cervical spondylotic myelopathy not only achieves similar effectiveness to 3D-printed artificial vertebral bodies, but also reduces operation time and the incidence of postoperative dysphagia.

[Treatment of cervical ossification of posterior longitudinal ligament with titanium alloy trabecular bone three-dimensional printed artificial vertebral body].

Objective: To evaluate the effectiveness of using titanium alloy trabecular bone three-dimensional (3D) printed artificial vertebral body in treating cervical ossification of the posterior longitudinal ligament (OPLL). Methods: A retrospective analysis was conducted on clinical data from 45 patients with cervical OPLL admitted between September 2019 and August 2021 and meeting the selection criteria. All patients underwent anterior cervical corpectomy and decompression, interbody bone graft fusion, and titanium plate internal fixation. During operation, 21 patients in the study group received titanium alloy trabecular bone 3D printed artificial vertebral bodies, while 24 patients in the control group received titanium cages. There was no significant difference in baseline data such as gender, age, disease duration, affected segments, or preoperative pain visual analogue scale (VAS) score, Japanese Orthopaedic Association (JOA) score, Neck Disability Index (NDI), vertebral height, and C 2-7Cobb angle ( P>0.05). Operation time, intraoperative blood loss, and occurrence of complications were recorded for both groups. Preoperatively and at 3 and 12 months postoperatively, the functionality and symptom relief were assessed using JOA scores, VAS scores, and NDI evaluations. The vertebral height and C 2-7 Cobb angle were detected by imaging examinations and the implant subsidence and intervertebral fusion were observed. Results: The operation time and incidence of complications were significantly lower in the study group than in the control group ( P<0.05), while the difference in intraoperative blood loss between the two groups was not significant ( P>0.05). All patients were followed up 12-18 months, with the follow-up time of (14.28±4.34) months in the study group and (15.23±3.54) months in the control group, showing no significant difference ( t=0.809, P=0.423). The JOA score, VAS score, and NDI of the two groups improved after operation, and further improved at 12 months compared to 3 months, with significant differences ( P<0.05). At each time point, the study group exhibited significantly higher JOA scores and improvement rate compared to the control group ( P<0.05); but there was no significantly difference in VAS score and NDI between the two groups ( P>0.05). Imaging re-examination showed that the vertebral height and C 2-7Cobb angle of the two groups significantly increased at 3 and 12 months after operation ( P<0.05), and there was no significant difference between 3 and 12 months after operation ( P>0.05). At each time point, the vertebral height and C 2-7Cobb angle of the study group were significantly higher than those of the control group ( P<0.05), and the implant subsidence rate was significantly lower than that of the control group ( P<0.05). However, there was no significant difference in intervertebral fusion rate between the two groups ( P>0.05). Conclusion: Compared to traditional titanium cages, the use of titanium alloy trabecular bone 3D-printed artificial vertebral bodies for treating cervical OPLL results in shorter operative time, fewer postoperative complications, and lower implant subsidence rates, making it superior in vertebral reconstruction.

[Analysis of imaging characteristics and effectiveness of cervical spondylotic myelopathy with cervical kyphosis].

Objective: To investigate the imaging characteristics of cervical kyphosis and spinal cord compression in cervical spondylotic myelopathy (CSM) with cervical kyphosis and the influence on effectiveness. Methods: The clinical data of 36 patients with single-segment CSM with cervical kyphosis who were admitted between January 2020 and December 2022 and met the selection criteria were retrospectively analyzed. The patients were divided into 3 groups according to the positional relationship between the kyphosis focal on cervical spine X-ray film and the spinal cord compression point on MRI: the same group (group A, 20 cases, both points were in the same position), the adjacent group (group B, 10 cases, both points were located adjacent to each other), and the separated group (group C, 6 cases, both points were located >1 vertebra away from each other). There was no significant difference between groups ( P>0.05) in baseline data such as gender, age, body mass index, lesion segment, disease duration, and preoperative C 2-7 angle, C 2-7 sagittal vertical axis (C 2-7 SVA), C 7 slope (C 7S), kyphotic Cobb angle, fusion segment height, and Japanese Orthopedic Association (JOA) score. The patients underwent single-segment anterior cervical discectomy with fusion (ACDF). The occurrence of postoperative complications was recorded; preoperatively and at last follow-up, the patients' neurological function was evaluated using the JOA score, and the sagittal parameters (C 2-7 angle, C 2-7 SVA, C 7S, kyphotic Cobb angle, and height of the fused segments) were measured on cervical spine X-ray films and MRI and the correction rate of the cervical kyphosis was calculated; the correlation between changes in cervical sagittal parameters before and after operation and the JOA score improvement rate was analyzed using Pearson correlation analysis. Results: In 36 patients, only 1 case of dysphagia occurred in group A, and the dysphagia symptoms disappeared at 3 days after operation, and the remaining patients had no surgery-related complications during the hospitalization. All patients were followed up 12-42 months, with a mean of 20.1 months; the difference in follow-up time between the groups was not significant ( P>0.05). At last follow-up, all the imaging indicators and JOA scores of patients in the 3 groups were significantly improved when compared with preoperative ones ( P<0.05). The correction rate of cervical kyphosis in group A was significantly better than that in group C, and the improvement rate of JOA score was significantly better than that in groups B and C, all showing significant differences ( P<0.05), and there was no significant difference between the other groups ( P>0.05). The correlation analysis showed that the improvement rate of JOA score was negatively correlated with C 2-7 angle and kyphotic Cobb angle at last follow-up ( r=-0.424, P=0.010; r=-0.573, P<0.001), and positively correlated with the C 7S and correction rate of cervical kyphosis at last follow-up ( r=0.336, P=0.045; r=0.587, P<0.001), and no correlation with the remaining indicators ( P>0.05). Conclusion: There are three main positional relationships between the cervical kyphosis focal and the spinal cord compression point on imaging, and they have different impacts on the effectiveness and sagittal parameters after ACDF, and those with the same position cervical kyphosis focal and spinal cord compression point have the best improvement in effectiveness and sagittal parameters.

[Application of modified acetabular anteversion and inclination angles test system in patients undergoing total hip arthroplasty after lumbar fusion].

Objective: To investigate the accuracy and effectiveness of acetabular cup placement in total hip arthroplasty (THA) after lumbar fusion applying of modified acetabular anteversion and inclination angles test system. Methods: A clinical data of 45 patients undergoing THA for osteoarthritis between January 2018 and June 2023 was retrospectively analyzed. All patients had previously received lumbar fusion. The modified acetabular anteversion and inclination angle test system was used in 26 cases (observation group) and not used in 19 cases (control group) during THA. There was no significant difference in baseline data such as gender, age, body mass index, operative side, number of lumbar fusion segments, and preoperative Harris score between the two groups ( P>0.05). The position of acetabular prosthesis, hip function (Harris score), and incidence of complications were compared between the two groups. Results: In the observation group, all acetabular cups were in the safe zone (anteversion angle, 25°-30°) during operation, and 1 acetabular cup (3.85%) was not in the safe zone after operation. In the control group, 9 acetabular cups (47.37%) were not in the safe zone. The postoperative difference between the two groups was significant ( P<0.05). There was no significant difference between intra- and post-operative acetabular inclination angles in the observation group ( P>0.05), and the postoperative acetabular inclination angle was significantly smaller in the observation group than in the control group ( P<0.05). All incisions healed by first intention and no infection occurred. All patients were followed up 6 months. There was no significant difference in Harris score between the two groups at different time point ( P>0.05), and there were significant differences between different time points in the two groups ( P<0.05). No joint dislocation occurred in the observation group during follow-up, while dislocation occurred in 2 cases and femoral impingement syndrome occurred in 1 case of the control group. There was no significant difference in the incidence of complications between the two groups ( P>0.05). Conclusion: For THA patients with lumbar fusion, the ideal placement angle of the acetabular cup can be obtained by using the modified acetabular anteversion and inclination angles test system during operation.

The effect of different fixation systems on oblique lumbar interbody fusion under vibration conditions.

Despite the fact that lower back pain caused by degenerative lumbar spine pathologies seriously affects the quality of life, however, there is a paucity of research on the biomechanical properties of different auxiliary fixation systems for its primary treatment (oblique lumbar interbody fusion) under vibratory environments. In order to study the effects of different fixation systems of OLIF surgery on the vibration characteristics of the human lumbar spine under whole-body vibration (WBV), a finite element (FE) model of OLIF surgery with five different fixation systems was established by modifying a previously established model of the normal lumbar spine (L1-S1). In this study, a compressive follower load of 500 N and a sinusoidal axial vertical load of ±40 N at the frequency of 5 Hz with a duration of 0.6 s was applied. The results showed that the bilateral pedicle screw fixation model had the highest resistance to cage subsidence and maintenance of disc height under WBV. In contrast, the lateral plate fixation model exerted very high stresses on important tissues, which would be detrimental to the patient's late recovery and reduction of complications. Therefore, this study suggests that drivers and related practitioners who are often in vibrating environments should have bilateral pedicle screws for OLIF surgery, and side plates are not recommended to be used as a separate immobilization system. Additionally, the lateral plate is not recommended to be used as a separate fixation system.

Finite element analysis of implanted lumbar spine: Effects of open laminectomy plus PLF and open laminectomy plus TLIF surgical approaches on L3-L4 FSU.

Several finite element (FE) studies reported performances of various lumbar fusion surgical approaches. However, comparative studies on the performance of Open Laminectomy plus Posterolateral Fusion (OL-PLF) and Open Laminectomy plus Transforaminal Interbody Fusion (OL-TLIF) surgical approaches are rare. In the current FE study, the variation in ranges of motions (ROM), stress-strain distributions in an implanted functional spinal unit (FSU) and caudal adjacent soft structures between OL-PLF and OL-TLIF virtual models were investigated. The implanted lumbar spine FE models were developed from subject-specific computed tomography images of an intact spine and solved for physiological loadings such as compression, flexion, extension and lateral bending. Reductions in the ROMs of L1-L5 (49 % to 59 %) and L3-L4 implanted FSUs (91 % to 96 %) were observed for both models. Under all the loading cases, the maximum von Mises strain observed in the implanted segment of both models exceeds the mean compressive yield strain for the vertebra. The maximum von Mises stress and strain observed on the caudal adjacent soft structures of both the implanted models are at least 22 % higher than the natural spine model. The findings indicate the risk of failure in the implanted FSUs and higher chances of adjacent segment degeneration for both models.

How does cervical sagittal profile change after the spontaneous compensation of global sagittal imbalance following one- or two-level lumbar fusion.

PURPOSE: This study aimed to evaluate the cervical sagittal profile after the spontaneous compensation of global sagittal imbalance and analyze the associations between the changes in cervical sagittal alignment and spinopelvic parameters. METHODS: In this retrospective radiographic study, we analyzed 90 patients with degenerative lumbar stenosis (DLS) and sagittal imbalance who underwent short lumbar fusion (imbalance group). We used 60 patients with DLS and sagittal balance as the control group (balance group). Patients in the imbalance group were also divided into two groups according to the preoperative PI: low PI group (≤ 50°), high PI group (PI > 50°). We measured the spinal sagittal alignment parameters on the long-cassette standing lateral radiographs of the whole spine. We compared the changes of spinal sagittal parameters between pre-operation and post-operation. We observed the relationships between the changes in cervical profile and spinopelvic parameters. RESULTS: Sagittal vertical axis (SVA) occurred spontaneous compensation (p = 0.000) and significant changes were observed in cervical lordosis (CL) (p = 0.000) and cervical sagittal vertical axis (cSVA) (p = 0.023) after surgery in the imbalance group. However, there were no significant differences in the radiographic parameters from pre-operation to post-operation in the balance group. The variations in CL were correlated with the variations in SVA (R = 0.307, p = 0.041). The variations in cSVA were correlated with the variations in SVA (R=-0.470, p = 0.001). CONCLUSION: Cervical sagittal profile would have compensatory changes after short lumbar fusion. The spontaneous decrease in CL would occur in patients with DLS after the spontaneous compensation of global sagittal imbalance following one- or two-level lumbar fusion. The changes of cervical sagittal profile were related to the extent of the spontaneous compensation of SVA.

Effects of intravenous single-bolus lidocaine infusion versus intravenous single-bolus magnesium sulfate infusion on postoperative pain, emotional status, and quality of life in patients undergoing spine fusion surgery: a randomized study.

BACKGROUND: We assessed the efficiency of intravenous adjuvants in decreasing opioid intake and pain scores after spine fusion surgery. METHODS: This study included 120 patients aged 18-60 listed for spine fusion surgery under general anesthesia. Patients were randomly assigned to four groups: Group (Lidocaine): received IV lidocaine 4 mg/kg in 50 mL volume over 30 min. Group (Magnesium): received IV magnesium sulfate 30mg/kg in 50 mL volume over 30 min. Group (combined Lidocaine and Magnesium): received IV lidocaine 4 mg/kg in 50 mL volume over 30 min.+IV magnesium sulfate 30mg/kg in 50 mL volume over 30 min. Group (Control): received IV saline 50 mL. The time to the first request analgesia, the postoperative pain score, total analgesic use, patient satisfaction, anxiety, depression, mental state, quality of life, and side effects were measured. RESULTS: The combined group had more extended time for the first analgesic request and fewer rescue analgesia doses than the other groups. NRS scores at rest or movement were statistically significantly lower in the lidocaine group and the combined group compared to the control group (P1, P3<0.05) at almost all times. This combination reduces anxiety and depression and improves overall health up to three months after a single infusion. The combined group had higher patient satisfaction. CONCLUSIONS: A synergistic effect of a combination of lidocaine and magnesium sulfate on perioperative pain was found. It reduces analgesic consumption, depression, and anxiety and improves overall health up to three months after a single infusion dose.