Comparison of full-endoscopic foraminoplasty and lumbar discectomy (FEFLD), unilateral biportal endoscopic (UBE) discectomy, and microdiscectomy (MD) for symptomatic lumbar disc herniation.

PURPOSE: This study aimed to evaluate the clinical outcomes of full-endoscopic foraminoplasty and lumbar discectomy (FEFLD), unilateral biportal endoscopic (UBE) discectomy, and microdiscectomy (MD) in the treatment of symptomatic lumbar disc herniation (LDH). METHODS: From January 2020 and May 2021, 128 patients with single-level LDH at L4-5 or L5-S1 received FEFLD, UBE discectomy or MD. Patients were divided into three groups according to surgical method: the FEFLD group (n = 43), the UBE group (n = 42), and the MD group (n = 43). Operative time, fluoroscopy frequency, in-bed time, length of hospital stays, total expenses, complications, visual analogue scale (VAS, 0-10), and Oswestry Disability Index (ODI, 0-100%) were assessed and compared among three groups. RESULTS: There were no significant differences in VAS or ODI scores at 12 months after surgery among three groups. In comparison with the MD group, the FEFLD and UBE group yield better VAS scores for back pain on the first day following surgery (P < 0.05). The FEFLD group was superior to the UBE group or MD group with less time in bed and shorter hospital stay (P < 0.05). The operation time and total expenses in the UBE group were significantly longer and higher than those in the FEFLD group or MD group (P < 0.05). CONCLUSIONS: FEFLD and UBE discectomy yield comparable results to conventional MD concerning pain relief and functional outcomes. In addition, FEFLD and UBE discectomy enable less back pain in the immediate postoperative period. FEFLD offers advantages in rapid recovery. Conventional MD is still an efficient and cost-effective surgical procedure.

Association between anemia and lumbar disc degeneration in patients with low back pain: an observational retrospective study.

OBJECTIVE: The goal of this study was to evaluate the possible associations between anemia and morphologic features of lumbar disc degeneration (LDD) in subjects with low back pain. MATERIALS AND METHODS: A total of 131 patients with normocytic or microcytic anemia (mean age 41.0 ± 6.4 yrs, BMI: 24.8 ± 3.3 kg/m2, 12.2% men) and a matched control group of 131 patients without anemia (mean age 41.0 ± 6.4 yrs, BMI: 24.9 ± 3.1 kg/m2, 12.2% men) were evaluated for LDD according to the Pfirrmann scoring system. The primary outcome was the difference of radiological features of LDD between two groups. The second outcome was the correlation between the hemoglobin (Hb) value and disc degeneration (DD). Statistical associations were assessed by Student's t-test, Chi-square test, and Spearman correlation. RESULTS: Anemic patients had a significantly higher number of degenerated discs than non-anemic patients in the level of L2/3 and L3/4 (p < 0.05). We also found that the severe DD occurred more frequently in the level of L2/3, L3/4 and L5/S1 among anemic patients (p < 0.05). In addition, we noticed that the incidence of multilevel LDD happened much more frequently in patients with anemia (p < 0.05). The Hb value showed a borderline negative correlation with the total score of DD (p = 0.056). CONCLUSION: The results suggested that patients with anemia, and those without are radiologically different with varying patterns of DD. Patients with back pain and anemia were more likely to have extensive and severe DD. Although relevant mechanisms are not yet well understood, this study improved our understandings of the pathophysiology for LDD.

Anemia was associated with multilevel lumbar disc degeneration in patients with low back pain: a single-center retrospective study.

PURPOSE: It has not been determined which factors were related to multilevel lumbar disc degeneration (MLDD). The objective of this study was to determine the prevalence of MLDD among symptomatic patients using the magnetic resonance imaging method. The study also aimed to clarify the associations between MLDD and suspected risk factors through a multivariate model. METHODS: A total of 530 young and middle-aged patients, suffered from low back pain were retrospectively assessed by 2 independent observers, who used sagittal T2-weighted MR imaging. Subjects were divided into two groups, MLDD group and non-MLDD group, according to the number of degenerated discs. Demographic and radiological data included age, gender, weight, height, body mass index, smoking status, alcohol drinking, lumbar lordosis, presence of hypertension (HT), diabetes mellitus and anemia. RESULTS: There were 309 men and 221 women with an average age of 37.5 ± 8.5 years. In general, 37.7% of patients were diagnosed with disc degeneration (DD) at more than two levels. Triple level DD was the most common pattern and was more prevalent in women (p <0.05). Using multivariate analyses, age (odds ratio [OR]: 1.14; 95% confidence interval [CI] 1.11-1.18; p <0.001), hypertension (OR: 2.67; 95% CI 1.38-5.16; p = 0.03) and anemia (OR: 3.84; 95% CI 2.03-7.28; p <0.001) were significantly associated with MLDD. CONCLUSION: Despite the young age of this cohort, MLDD is common among patients with low back pain. A significant independent association exists between age, HT, anemia and multilevel disc degeneration in the lumbar region.

Clinical application of the C2 pars screw technique in the treatment of ossification of the posterior longitudinal ligament.

BACKGROUND: Our research was designed to decide whether the application of C2 pars screws is an alternative choice for patients with OPLL involving the C2 segment. METHODS: A total of 40 patients who underwent cervical laminectomy with fusion (LF) from C2 to C6 for OPLL were reviewed. Among them, C2 pedicle screws were placed in 23 patients, who were the pedicle group, and C2 pars screws were placed in 17 patients, who were the pars group. The screw placement and vertebral artery (VA) anatomy presented by standard CT. General clinical characteristics and health-related outcomes were evaluated and compared preoperatively and during the follow-up period. RESULTS: The Pars group tended to have a shorter operation duration and less blood loss than the pedicle group (operation time: 115.29 ± 28.75 vs 133.48 ± 26.22, p = 0.044; blood loss: 383.53 ± 116.19 vs 457.83 ± 145.45, p = 0.039). Operation time and blood loss were both independently related to the pars group (operation time: OR = 0.966, p = 0.021; blood loss: OR = 0.993, p = 0.046). The idealization and acceptability of C2 screws in the pars group exceeded those in the pedicle group (100% vs 91.3%). However, no statistically obvious variation in the included complications or health-related outcomes between the pedicle and pars groups was observed. CONCLUSION: In the treatment of patients with OPLL involving the C2 segment, the application of C2 pars screws is an alternative choice, which is not only safer but also reduces the amount of blood loss, shortens the operation time and obtains a more ideal screw placement.

Spino cranial angle as a predictor of loss of cervical lordosis after laminoplasty in patients with cervical myelopathy.

BACKGROUND: To explore the relationship between spino cranial angle (SCA) and loss of cervical lordosis (LOCL), and to determine whether SCA has the ability to predict LOCL for patients with cervical myelopathy. METHODS: A total of 68 consecutive patients with cervical myelopathy who received laminoplasty (LAMP) were selected to the current study. C2-C7 lordosis was defined as a representation of the cervical alignment. Alignment change > 0° was considered LOCL. Multiple linear regression analysis was applied to evaluate the association between LOCL and various sagittal parameters at preoperative, such as SCA, CL, T1s and cSVA. Linear regression analysis was applied to evaluate the relationships between LOCL and preoperative SCA in each subgroup. RESULTS: Patients were assigned to three groups depending on the quartile of preoperative SCA. The first quarter of patients were defined as the low SCA group, the last quarter were defined as the high SCA group and the middle half were defined as the middle SCA group. There was no statistically significant difference in age, sex and the type of OPLL among the three groups. Patients in the low SCA group showed more cervical lordosis before surgery and more LOCL after LAMP (p < 0.001). After linear regression analysis for SCA and LOCL, preoperative SCA was negatively correlated with LOCL in the low SCA group (r = - 0.857, p < 0.001) and high SCA group (r = - 0.515, p = 0.034). However, there was no significant correlation between preoperative SCA and LOCL in the middle SCA group (r = 0.027, p = 0.881). CONCLUSIONS: Patients with lower SCA had more lordosis preoperatively and performed more LOCL after LAMP at 2 years of follow-up. Both too high or low preoperative SCA were negatively correlated with the degree of LOCL, while when the SCA fluctuates in a suitable range, it is easier to compensate for the changes of cervical sagittal alignment.

The degree of fracture displacement does not affect the risk for concomitant proximal fibular fractures in tibial plateau fractures.

OBJECTIVE: The proximal fibula plays an important role in the knee joint; however, it has not been given enough attention by surgeons. This study aimed to investigate the risk factors for concomitant proximal fibular fractures in patients with tibial plateau fractures through computed tomography (CT) imaging. MATERIALS AND METHODS: From January 2016 to November 2017, patients who underwent percutaneous reduction and internal fixation (PRIF) for tibial plateau fractures at a level 1 trauma centre institute were included in this retrospective study. Full materials of CT imaging were obtained for measurements. Schatzker's and a newly proposed classification system were used for the fracture of the tibial plateau and proximal fibula, respectively. Several clinical and radiological characteristics were recorded, and the impact of those variables on fibular fractures was assessed with univariate and multivariate analyses. RESULTS: In total, 174 patients were enrolled in the study with mean age of 45.6±13.1 years. The incidence of combined proximal fibular fracture was 38.3%. Schatzker type VI fracture had the highest rate of fibular fracture (77.4%). High-energy-pattern tibial plateau fractures (p=0.029) and posterolateral joint facet (PJF) involvements (p=0.002) are risk factors for proximal fibular fracture on multivariate analysis. Neither posterolateral column (PLC) involvements nor fracture displacement correlated with proximal fibular fractures. CONCLUSIONS: Proximal fibular fractures were commonly seen among patients who sustained tibial plateau fractures. Schatzker type VI fractures had the highest rate of fibular fractures than other fracture types. High-energy fractures and PJF involvements correlated with a higher risk of proximal fibular fractures. A better understanding and awareness of the risk factors for proximal fibular fractures will provide surgeons with comprehensive understanding of tibial plateau fractures.

Iron regulatory protein 2 deficiency may correlate with insulin resistance.

Iron is known to be a crucial regulator of glucose, and several studies have demonstrated that iron overload is one of the risk factors for insulin resistance and diabetes; however, the mechanism has not yet been clarified. To investigate the effect of iron overload on glucose metabolism and the underlying mechanism, Irp2 knockout (Irp2-/-) mice (endogenous iron overload model) were used. We found that Irp2-/- mice exhibited hyperglycemia and iron overload in the liver and skeletal muscle. Increased MDA, decreased SOD levels, and increased cell apoptosis were also found in the liver and muscle of Irp2-/- mice. Glucose concentrations were significantly higher in Irp2-/- mice in insulin tolerance tests. However, early-phase insulin secretion was not altered in Irp2-/- mice. The expression of hepatic IRS2 and muscle GLUT4 was declined in Irp2-/- mice at both mRNA and protein levels when compared with those of wild-type control. In conclusions, Irp2-/- mice showed hyperglycemia, which might due to insulin resistance rather than due to impaired insulin secretion.

Irp2 Knockout Causes Osteoporosis by Inhibition of Bone Remodeling.

It has been found that iron disorder may lead to osteoporosis. However, the mechanism has been little explored. In the present study, we try to investigate the effects of iron disorder on bone metabolism using Irp2 knockout (Irp2-/-) mice. Female Irp2-/- mice were used in this study. Bone mineral density (BMD) was measured by Micro-CT. Serum markers for bone turnover were measured by enzyme-linked immunosorbent assay. Content of iron was measured in bone and liver tissue, and Vitamin D 25-hydroxylase (CYP2R1) content was measured in liver tissue. Relative gene expression involved in iron export and uptake, and some genes involved in activities of osteoblast and osteoclast were all measured by real-time PCR and western blot. Compared to wild-type mice, Irp2-/- mice exhibited reduced BMD, bone iron deficiency, and hepatic iron overload. Serum levels of 25(OH)D3 and markers for bone formation such as bone alkaline phosphatase (Balp), bone-gla-protein (BGP), and type I collagen alpha1 chain (Col I α1) were decreased, while markers for bone resorption including cathepsin K (Ctsk) and tartrate-resistant acid phosphatase (Trap) were all significantly increased. Hepatic CYP2R1 level was decreased in Irp2-/- mice compared with wild-type control mice. Compared to wild-type C57BL6 control mice, the expression of genes involved in osteoblast activity such as Balp, BGP, and Col I α1 were all significantly decreased in bone tissue, while genes for osteoclast activity such as Ctsk and Trap were all markedly increased in Irp2-/- mice at mRNA level. Genes involved in iron storage, uptake, and exporting were also measured in bone tissue. Posttranscriptionally decreased ferritin (FTL), ferroportin 1 (FPN1), and increased transferrin receptor 1 (TfR1) gene expressions have been unexpectedly found in bone tissue of Irp2-/- mice. Irp2-/- mice exhibit reduced bone iron content and osteoporosis. Decreased circulating 25(OH)D3 levels promoted activity of osteoclast, while impaired activity of osteoblast may contribute to pathogenesis of osteoporosis. And, reduced bone iron content may not be totally caused by TfR1-dependent pathways.

The use of bidirectional rapid reductor in minimally invasive treatment of bicondylar tibial plateau fractures: preliminary radiographic and clinical results.

BACKGROUND: Minimally invasive treatment of complex tibial plateau fracture represents one of the most challenging problems in orthopedic surgery. We intended to describe the percutaneous surgery involving an originally designed traction device which might facilitate the closed reduction for bicondylar tibial plateau fractures. Further, to assess the clinical outcomes of this minimally invasive technique. METHODS: Between December 2015 and July 2016, Twenty-one patients, mean age 43.71 ± 13.80 years, suffering from a bicondylar tibial plateau fracture (AO/OTA 41-type C) were included. All fractures were firstly reduced by skeletal traction with the aid of bidirectional rapid reductor, and residual depressed fragments were treated with minimally invasive bone tamp reduction. We then evaluated at a minimum follow-up of one year: (1) the rate of complications, (2) the radiographic outcomes (the amount of depression, tibial plateau widening, tibial plateau angle and posterior slope angle) and (3) the clinical outcome (Rasmussen scoring system). RESULTS: All patients had their fractures healed without secondary displacement. No instrument-related complications occurred during operation. Post-operatively, superficial infection was found in two patients and donor-site morbidity was found in one patient. We observed a < 5 mm step-off in 100% of patients and a < 5 mm plateau widening in 95.5% of patients. Three patients were considered indicative of malalignment with TPA > 90° or PSA > 15°. At last evaluation, the Rasmussen clinical score was excellent in 11 patients (52.3%), good in 9 (42.9%) and fair in 1 (4.8%), and the radiological score was excellent in seven patients (33.3%), good in 14 (66.7%). CONCLUSIONS: The bidirectional rapid reductor facilitates the minimally invasive treatment of bicondylar tibial plateau fracture. The patients exhibited excellent functional recovery. These results should be validated with a larger group of patients and longer period results. TRIAL REGISTRATION: ChiCTR-OPC-16008011 .

A novel method of using elastic bionic fixation device for distal tibiofibular syndesmosis injury.

PURPOSE: To describe and evaluate the novel method of using elastic bionic fixation device in treating the distal tibiofibular syndesmosis (DTS) injury. METHODS: From June 2013 to January 2014, 17 subjects with ankle fractures combined with DTS separation were treated by the elastic bionic fixation device. The syndesmotic parameters, healing, functional scores, and possible complications were recorded. RESULTS: All patients had a mean follow-up of 23.35 ± 4.39 months (range, 15-28 months). Syndesmotic parameters returned to normal after surgery and remained normal throughout the follow-up period. X-ray examinations at 12 months follow-up showed no cable breakage of the elastic bionic fixation device or instrument invalidation compared to that of immediate post-operative X-ray films. Besides, no signs of articular degeneration and arthritis were observed. Furthermore, change in bone density near the fibular fixing button or tibial screw nut was also not detected. Primary wound healing was observed in 16 patients, while the remaining one showed redness and swelling of lateral ankle incision and got wound healing after seven to ten  days of antibiotic therapy and local radio frequency physiotherapy. All obtained excellent and good outcomes according to the AOFAS score at 12 months after surgery. CONCLUSIONS: The use of elastic bionic fixation device appears to be a promising option in treating DTS injury because it can provide stable and reliable elastic fixation, good functional recovery, and relatively fewer complications.

Meta-analysis suggests that the electromagnetic technique is better than the free-hand method for the distal locking during intramedullary nailing procedures.

OBJECTIVES: To evaluate the comparative effectiveness and accuracy of electromagnetic technique (EM) verses free-hand method (FH) for distal locking in intramedullary nailing procedure. MATERIAL AND METHODS: Relevant original studies were searched in Medline, Pubmed, Embase, China National Knowledge Infrastructure, and Cochrane Central Database (all through October 2015). Comparative studies providing sufficient data of interest were included in this meta-analysis. The Stata 11.0 was used to analyze all data. RESULTS: Eight studies involving 611 participants were included, with 305 in EM group and 306 in FH group. EM outperformed FH with reduced distal locking time of 4.1 minutes [standardized mean difference (SMD), 1.61; 95 % confidence interval (95 %CI), 0.81 to 2.41] and the reduced fluoroscopy time of 25.3 seconds (SMD, 2.64; 95 %CI, 2.12 to 3.16). Regarding the accuracy of distal screw placement, no significant difference was observed between two techniques (OR, 2.39; 95 %CI, 0.38 to 15.0). There was a trend of longer operative time in FH versus EM by 10 minutes (79.0 and 69.0 minutes), although the difference was not statistically significant (SMD, 0.341; 95 % CI, -0.02 to 0.703). CONCLUSIONS: The existing evidence suggests EM technique is a better alternative for distal locking in intramedullary nailing procedure, and this might aid in the management of diaphyseal fractures in lower extremities.

Intramedullary nail versus volar locking plate fixation for the treatment of extra-articular or simple intra-articular distal radius fractures: systematic review and meta-analysis.

AIMS: This study aims to compare the outcomes of intramedullary nail (IMN) and volar locking plate (VLP) fixation for treatment of extra-articular or simple intra-articular distal radius fractures. METHODS: PubMed, Embase, Medline and Cochrane Collaboration Central databases were searched for studies that compared the results of IMN and VLP fixation for the treatment of distal radius fractures up to March 2016. Stata 11.0 was used to perform the meta-analysis. RESULTS: Six randomized controlled trials (RCT) and two retrospective studies were included in this review, including 463 patients. No significant differences were found between two treatment methods in terms of any functional score, radiographic parameters and motion range in the late post-operative period (6, 12 and 24 months). However, IMN did better than VLP at the post-operative six weeks and three months, no matter which functional scoring system was used. The incidence of carpal tunnel syndrome (CTS) was 8.7% in the VLP group, significantly higher than that (0.8%) in the IMN group (OR, 0.183; 95%CI, 0.045-0.74). But for other complications, such as infection (OR, 0.449; 95%CI, 0.095-2.114), tendious damage (OR, 0.931; 95%CI, 0.238-3.648), tenosynovitis (OR, 0.806; 95%CI, 0.209-3.108), algodystrophy (pain) (OR, 0.795; 95%CI, 0.291-2.173) and radial nerve paraesthesia (OR, 1.8143; 95%CI, 0.834-3.942), no significant differences were found (P > 0.05). CONCLUSIONS: Compared to VLP, IMN could provide better early postoperative functional outcomes and reduce the incidence of carpal tunnel syndrome, which could be of particular help in restoring confidence for workers with specialized manual skills to return to their prior jobs. Additionally, the conclusion should be cautiously treated, because it was reached in the context of limited amount of studies and relatively small sample size. Therefore, future studies with good design and large samples are required to verify this conclusion.

Meta-analysis shows that highly comminuted bicondylar tibial plateau fractures treated by single lateral locking plate give similar outcomes as dual plate fixation.

OBJECTIVES: This meta-analysis was conducted to compare the clinical outcomes of single lateral locking plate (SP) versus dual plate fixation (DP) for the repair of bicondylar tibial plateau fractures (AO/OTA type C or Schatzker type V and VI). METHODS: PubMed, Embase, Medline, CNKI, Wanfang database and Chinese VIP information were searched to identify the randomized and prospective comparative clinical studies which concern the treatment of bicondylar tibial plateau fractures (AO/OTA type C or Schatzker type V and VI) both with SP and DP fixation before October 1, 2015. STATA version 11.0 (Stata Corporation, College Station, TX, USA) was used for data-analysis after the critical assessment of the methodological quality of the trials. RESULTS: Finally, nine trials comprising 559 patients were included for this meta-analysis after the filtration. There were no significant differences between SP fixation and DP fixation with regards to outcomes for bone graft, post-operative malalignment and post-operative malreduciton in surgical details; infection, venous thrombosis, implant irritation and loss of reduction in complications; knee motion range in final outcomes. Lower surgical time, hospital stay, union time and incision necrosis were found in SP fixation compared with DP fixation. High rate of loss of alignment and more satisfaction with 12-month HSS score were associated with SP fixation than with DP fixation. CONCLUSIONS: Both SP fixation and DP fixation are acceptable strategies for managing this type of fracture. However, more high quality RCTs with large number of patients and long-term clinical evaluations are required to determine the optimal strategy for bicondylar tibial plateau fractures.

Full-Endoscopic Foraminoplasty and Lumbar Discectomy for Single-Level Lumbar Disc Herniation.

The Transforaminal Endoscopic Surgical System (TESSYS) technique has gained popularity for the treatment of lumbar disc herniations. Foraminoplasty is the key procedure in TESSYS. However, it requires advanced skills and long-term learning, which hinder its widespread adoption among surgeons. Recently, the introduction of full-endoscopic solutions has made the process more manageable. The main difference from traditional single-portal endoscopic surgery is that full-endoscopic surgery is equipped with a larger working channel, allowing full visualization of foraminoplasty and decreasing reliance on intraoperative fluoroscopy. Recently, published studies have shown that full-endoscopic foraminoplasty and lumbar discectomy (FEFLD) could achieve comparable results to conventional microdiscectomy in terms of pain relief and functional outcomes, while enhancing postoperative recovery. This study describes the technique of FEFLD in detail, including every crucial step, such as patient positioning, puncture trajectory, endoscopic dissection of the superior articular process (SAP), endoscopic foraminoplasty, and more. We hope this will be helpful to beginners who wish to apply this approach.

Characteristic of Paraspinal Muscle Change in Coronal Sub-type of Degenerative Lumbar Scoliosis and its Potential Clinical Significance.

OBJECTIVE: Clarifying paraspinal muscle (PM) change in degenerative lumbar scoliosis (DLS) is positive to evaluate the progression of scoliosis. This research compares the characteristic of PM change among different coronal sub-types of DLS and explores its potential clinical significance. METHODS: A total of 84 DLS patients between June 2019 to December 2021 were retrospectively analyzed. Patients were classified into three types based on the coronal balance distance (CBD): Type A, CBD <3 cm; Type B: C7 Plumb Line (C7PL) shifted to the concave side of the curve, and CBD >3 cm; Type C: C7PL shifted to the convex side of the curve, and CBD >3 cm. Fat infiltration rates in the multifidus (MS) and erector spinae (ES) at the apex of the main and fractional curves, and spinopelvic parameters were analyzed statistically. Pearson's or Spearman's correlation was applied to analyze the correlation between asymmetric degree of PM change and these parameters in three types. RESULTS: There were 62 cases with coronal sub-Type A, 6 cases with Type B, and 16 cases with Type C. Patients in Type B and C demonstrated higher fat infiltration in MS on the concave side of both the main and fractional curves when compared to those in Type A. The asymmetric degree of ES change was positively correlated with CBD at the apex of the main curve in Type B and at the apex of the fractional curve in Type C respectively, and that of MS was positively correlated with apical vertebral rotation, while negatively strong-correlated with pelvic incidence and sacral slope in Type C. CONCLUSION: PM fatty infiltration presented difference among varied coronal sub-types of DLS patients. The CBD in Type B and C patients was correlated with the asymmetric degree of ES change.

Reconsideration and Reflection on Spinal Disorders Through the Study of Intervertebral Discs in Patients with Lumbar Spondylolisthesis.

OBJECTIVE: This study analyzed and explored the relationship between isthmic spondylolisthesis and disc degeneration by comparing the degree of disc degeneration in patients with isthmic spondylolisthesis, lumbar disc herniation, and asymptomatic healthy individuals. METHODS: This study included a total of 138 cases, consisting of L5-S1 single segment lesion patients and a normal lumbar spine population. The cases were divided into 3 groups based on the type of disease: fifty eight cases in the isthmic spondylolisthesis (IS) group, 50 cases in the lumbar disc herniation (LDH) group, and 30 cases in the normal lumbar vertebrae (NLV) group. RESULTS: The research findings indicate that the proportion of intervertebral disc degeneration in the LDH group is significantly higher than that in the IS group and NLV group (65.3% vs. 33.3% vs. 25.8%, P < 0.05). The Pfirrmann grades of lumbar intervertebral discs (L1-L4) in the LDH group are significantly higher than those in the IS group and NLV group (P < 0.05), and the intervertebral height index (IHI) (L1-L4) of lumbar vertebrae in the LDH group is significantly lower than that in the IS group and NLV group (P < 0.05). CONCLUSIONS: The results showed that the degree of intervertebral disc degeneration in patients with isthmic spondylolisthesis was lighter than that in patients with LDH, and even similar to that in healthy individuals. The occurrence of IS may have slowed down the degeneration of nonaffected segment intervertebral discs through certain factors.

Is Intervertebral Disc Degeneration a Compensatory Mechanism in Adult Tethered Cord Syndrome?

OBJECTIVE: The purpose of the present study was to evaluate the influence of high nerve tension on lumbar disc degeneration and sagittal morphologies. MATERIALS AND METHODS: A total of 50 young and middle-aged patients (mean age 32.1 ± 7.4 years, 22 men and 28 women) who suffered from tethered cord syndrome (TCS) were retrospectively assessed by two observers. Demographic and radiological data were recorded, including lumbar disc degeneration, disc height index and lumbar spine angle, and were compared with 50 patients (mean age 29.7 ± 5.4 years, 22 men and 28 women) without spinal cord abnormalities. Statistical associations were assessed by student's t-test and chi-square test. RESULTS: Our results showed patients with TCS had a significantly higher rate of lumbar disc degeneration in L1/2, L2/3, L4/5 and L5/S1 than in those without TCS (P < 0.05). Moreover, the rates of multilevel disc degeneration and severe disc degeneration in TCS group were significantly higher than those in control group (P < 0.01). The mean disc height index of L3/4 and L4/5 in TCS group was significantly lower than that in control group (P < 0.05). The mean lumbosacral angle of TCS patients was significantly higher than that of patients without TCS (38.4 ± 3.5°vs. 33.7 ± 5.9°, P < 0.01). CONCLUSIONS: We found a certain correlation between TCS and lumbar disc degeneration and lumbosacral angle enlargement, suggesting that the spine reduces the high tension of the spinal cord through disc degeneration. Therefore, it is speculated that there is a "compromised regulation" mechanism in the body under the condition of neurological abnormalities.

Influence of prazosin on systemic iron levels and the associated iron metabolic alterations in spontaneously hypertensive rats.

The relationship between cardiovascular diseases and iron disorders has gained increasing attention; however, the effects of hypotensive drugs on iron metabolic alterations in hypertension are not well understood. The purpose of this study was to investigate iron metabolic changes after prazosin treatment of spontaneously hypertensive rats (SHRs) and Wistar-Kyoto (WKY) rats. Our second objective was to examine the effects of hypertension and anti-hypertensive drugs on bone formation and resorption. SHRs and WKY rats were randomized into either prazosin-treated groups (WKY + PZ and SHR + PZ) or untreated groups (WKY and SHR). After 7 days of intragastric prazosin administration, the rats were sacrificed for analysis; blood samples and organs (the duodenum, liver, kidneys, spleen, and femur) were collected. Both WKY + PZ and SHR groups exhibited iron deficiency in the serum and liver. Prazosin increased the iron levels in the bone tissue of SHRs. Prazosin stimulated the expression of hepcidin mRNA in the liver of SHRs and inhibited the expression of this iron-regulatory hormone in WKY rats. FPN1 expression in the duodenum was increased significantly in SHRs, however markedly decreased after prazosin treatment. The expression of TLR4 and Ctsk was enhanced in the bone tissue of SHRs, whereas CLC-7 expression was inhibited. Both hypotension and hypertension can lead to iron deficiency. Treatment with prazosin restored iron homeostasis in SHRs. The inverse impacts of prazosin on hepatic hepcidin expression in SHRs versus WKY rats indicates differing iron regulatory mechanisms between hypertensive and normal animals. The osteoclast activity was found to be enhanced in SHRs. Further study is needed to address whether the changes in osteoblast and osteoclast activity in SHRs correlates with the effects on iron metabolism.

Biomechanical Evaluation of Oblique Lumbar Interbody Fusion with Various Fixation Options: A Finite Element Analysis.

OBJECTIVE: The aim of the present study was to clarify the biomechanical properties of oblique lumbar interbody fusion (OLIF) using different fixation methods in normal and osteoporosis spines. METHODS: Normal and osteoporosis intact finite element models of L1 -S1 were established based on CT images of a healthy male volunteer. Group A was the normal models and group B was the osteoporosis model. Each group included four subgroups: (i) intact; (ii) stand-alone cage (Cage); (iii) cage with lateral plate and two lateral screws (LP); and (iv) cage with bilateral pedicle screws and rods (BPSR). The L3 -L4 level was defined as the surgical segment. After validating the normal intact model, compressive load of 400 N and torsional moment of 10 Nm were applied to the superior surface of L2 to simulate flexion, extension, left bending, right bending, left rotation, and right rotation motions. Surgical segmental range of motion (ROM), cage stress, endplate stress, supplemental fixation stress, and stress distribution were analyzed in each group. RESULTS: Cage provided the minimal reduction of ROM among all motions (normal, 82.30%-98.81%; osteoporosis, 92.04%-97.29% of intact model). BPSR demonstrated the maximum reduction of ROM (normal, 43.94%-61.13%; osteoporosis, 45.61%-62.27% of intact model). The ROM of LP was between that of Cage and BPSR (normal, 63.25%-79.72%; osteoporosis, 70%-87.15% of intact model). Cage had the minimal cage stress and endplate stress. With the help of LP and BPSR fixation, cage stress and endplate stress were significantly reduced in all motions, both in normal and osteoporosis finite element models. However, BPSR had more advantages. For cage stress, BPSR was at least 75.73% less than that of Cage in the normal model, and it was at least 80.10% less than that of Cage in the osteoporosis model. For endplate stress, BPSR was at least 75.98% less than that of Cage in the normal model, and it was at least 78.06% less than that of Cage in the osteoporosis model. For supplemental fixation stress, BPSR and LP were much less than the yield strength in all motions in the two groups. In addition, the comparison between the two groups showed that the ROM, cage stress, endplate stress, and supplemental fixation stress in the normal model were less than in the osteoporosis model when using the same fixation option of OLIF. CONCLUSION: Oblique lumbar interbody fusion with BPSR provided the best biomechanical stability both in normal and osteoporosis spines. The biomechanical properties of the normal spine were better than those of the osteoporosis spine when using the same fixation option of OLIF.