Biomechanical effects of different instrumented segments and trunk shifts on distal adjacent segments after congenital scoliosis posterior hemivertebrectomy: Preliminary results of a single case.

Objective: The present study aims to discuss the biomechanical effects of the sagittal vertical axis and different instrumented segments on distal adjacent segments after congenital scoliosis posterior hemivertebrectomy. Method: A case of congenital scoliosis caused by hemivertebra was selected for the reconstruction of the preoperative and postoperative 3D computed tomography data of the full spine. A finite element model of different fusion lengths and postoperative trunk shift (TS) values was established using the finite element method to compare the biomechanical effects of different models on the distal adjacent segment. Result: In the L1-L3 and T12-L1-L3-L4 fusion modes, the horizontal shift of the 1st vertebra below the lowest instrumented vertebra (LIV) increased with the trunk shift (TS) expansion after operation, and the imbalance between the left and right vertical stress of the 1st intervertebral disc below the LIV increased. With the decrease in fused segments in cases of TS = 10 mm and TS = 5 mm, the 1st vertebra below the LIV was subjected to a greater unbalanced force in the horizontal direction, and the 1st intervertebral disc below the LIV was subjected to a smaller imbalance between the left and right vertical stress after operation. Conclusion: When treating congenital scoliosis with hemivertebrectomy and pedicle screw fixation, fused segments can be properly extended and the postoperative TS shortened with a view of reducing the imbalance between the left and right stress of the 1st intervertebral disc below the LIV as well as the horizontal shift of the 1st vertebra below the LIV.

Harnessing developmental dynamics of spinal cord extracellular matrix improves regenerative potential of spinal cord organoids.

Neonatal spinal cord tissues exhibit remarkable regenerative capabilities as compared to adult spinal cord tissues after injury, but the role of extracellular matrix (ECM) in this process has remained elusive. Here, we found that early developmental spinal cord had higher levels of ECM proteins associated with neural development and axon growth, but fewer inhibitory proteoglycans, compared to those of adult spinal cord. Decellularized spinal cord ECM from neonatal (DNSCM) and adult (DASCM) rabbits preserved these differences. DNSCM promoted proliferation, migration, and neuronal differentiation of neural progenitor cells (NPCs) and facilitated axonal outgrowth and regeneration of spinal cord organoids more effectively than DASCM. Pleiotrophin (PTN) and Tenascin (TNC) in DNSCM were identified as contributors to these abilities. Furthermore, DNSCM demonstrated superior performance as a delivery vehicle for NPCs and organoids in spinal cord injury (SCI) models. This suggests that ECM cues from early development stages might significantly contribute to the prominent regeneration ability in spinal cord.

Percutaneous transforaminal endoscopic decompression with removal of the posterosuperior region underneath the slipping vertebral body for lumbar spinal stenosis with degenerative lumbar spondylolisthesis: a retrospective study.

BACKGROUND: Percutaneous transforaminal endoscopic decompression (PTED) is an ideal minimally invasive decompression technique for the treatment of lumbar spinal stenosis (LSS) with degenerative lumbar spondylolisthesis (DLS). The posterosuperior region underneath the slipping vertebral body (PRSVB) formed by DLS is an important factor exacerbating LSS in patients. Therefore, the necessity of removing the PRSVB during ventral decompression remains to be discussed. This study aimed to describe the procedure of PTED combined with the removal of the PRSVB and to evaluate the clinical outcomes. METHODS: LSS with DLS was diagnosed in 44 consecutive patients at our institution from January 2019 to July 2021, and they underwent PTED combined with the removal of the PRSVB. All patients were followed up for at least 12 months. The clinical outcomes were evaluated using the visual analog scale (VAS), Oswestry Disability Index (ODI), and modified MacNab criteria. RESULTS: The mean age of the patients was 69.5 ± 7.1 years. The mean preoperative ODI score, VAS score of the low back, and VAS score of the leg were 68.3 ± 10.8, 5.8 ± 1.0, and 7.7 ± 1.1, respectively, which improved to 18.8 ± 5.0, 1.4 ± 0.8, and 1.6 ± 0.7, respectively, at 12 months postoperatively. The proportion of patients presenting "good" and "excellent" ratings according to the modified MacNab criteria was 93.2%. The percent slippage in spondylolisthesis preoperatively (16.0% ± 3.3%) and at the end of follow-up (15.8% ± 3.3%) did not differ significantly (p>0.05). One patient had a dural tear, and one patient had postoperative dysesthesia. CONCLUSIONS: Increasing the removal of PRSVB during the PTED process may be a beneficial surgical procedure for alleviating clinical symptoms in patients with LSS and DLS. However, long-term follow-up is needed to study clinical effects.

Mimicked Spinal Cord Fibers Trigger Axonal Regeneration and Remyelination after Injury.

Spinal cord injury (SCI) causes tissue structure damage and composition changes of the neural parenchyma, resulting in severe consequences for spinal cord function. Mimicking the components and microstructure of spinal cord tissues holds promise for restoring the regenerative microenvironment after SCI. Here, we have utilized electrospinning technology to develop aligned decellularized spinal cord fibers (A-DSCF) without requiring synthetic polymers or organic solvents. A-DSCF preserves multiple types of spinal cord extracellular matrix proteins and forms a parallel-oriented structure. Compared to aligned collagen fibers (A-CF), A-DSCF exhibits stronger mechanical properties, improved enzymatic stability, and superior functionality in the adhesion, proliferation, axonal extension, and myelination of differentiated neural progenitor cells (NPCs). Notably, axon extension or myelination has been primarily linked to Agrin (AGRN), Laminin (LN), or Collagen type IV (COL IV) proteins in A-DSCF. When transplanted into rats with complete SCI, A-DSCF loaded with NPCs improves the survival, maturation, axon regeneration, and motor function of the SCI rats. These findings highlight the potential of structurally and compositionally biomimetic scaffolds to promote axonal extension and remyelination after SCI.

A Comparative Study of Unilateral Biportal Endoscopic Decompression and Percutaneous Transforaminal Endoscopic Decompression for Geriatric Patients with Lumbar Lateral Recess Stenosis.

Purpose: The purpose of this research was to compare the efficacy of unilateral biportal endoscopic decompression (UBE) and percutaneous transforaminal endoscopic decompression (PTED) in the treatment of elderly patients with single-level lumbar lateral recess stenosis (LRS). Materials and Methods: Data from January 2020 to March 2022 were analyzed. Thirty-eight patients in the PTED group and thirty-nine patients in the UBE group completed the minimum 12-month follow-up. The demographic data and perioperative outcomes were reviewed. Clinical outcomes were evaluated using the VAS for back and leg pain, the Oswestry Disability Index (ODI), and the modified MacNab criteria. Results: Both groups of patients completed surgery and a one-year follow-up. There was no significant difference between the two groups in demographics data. UBE has the advantage in operative duration and X-ray time; as far as incision length, blood loss, and drainage volume are concerned, PTED is advantageous. Under the modified MacNab criteria, UBE exhibited a good-to-excellent rate similar to that of PTED (84.6% vs 81.6%, P>0.05). There were no significant differences at any point in time between UBE and PTED with respect to ODI, VAS, or back pain scores (P>0.05). UBE and PTED did not differ significantly in terms of complications. Conclusion: Both PTED and UBE achieved favorable outcomes in single-level LRS. For operative time and X-ray times, UBE is more advantageous, while PTED offers better estimates of blood loss, incision length, and drainage volume.

Percutaneous Pedicle Screw Fixation with Percutaneous Endoscopic Transforaminal Lumbar Interbody Fusion in the Treatment of Degenerative Lumbar Spondylolisthesis with Instability.

OBJECTIVE: To evaluate the safety and efficacy of percutaneous endoscopic transforaminal lumbar interbody fusion (PE-TLIF) in patients with L4-L5 degenerative lumbar spondylolisthesis (DLS) with instability. METHODS: The clinical data of 27 patients with L4-L5 DLS who underwent PE-TLIF from September 2019 to April 2022 were retrospectively reviewed. A minimum of 12 months of follow-up visits was provided to all patients. The demographics, perioperative, and clinical outcomes were reviewed based on the visual analog scale (VAS), Oswestry Disability Index (ODI), and modified MacNab criteria. Brantigan criteria estimated the result of interbody fusion at 12 months. RESULTS: The mean age was 70.70 ± 8.91 (55-83) years. The mean ± standard deviation values of the preoperative visual analog scale for back pain, leg pain, and Oswestry Disability Index were 7.37 ± 1.01, 7.26 ± 0.94, and 66.22 ± 7.49, respectively. The values improved to 1.66 ± 0.62, 1.74 ± 0.52, and 19.55 ± 5.56 at 12 months postoperatively (P ＜ 0.05). The modified MacNab criteria revealed that 88.89% (24/27) of patients achieved good-to-excellent outcomes. The interbody fusion rate was 100% at the final follow-up. CONCLUSIONS: In patients with L4-L5 DLS with instability, PE-TLIF under conscious sedation and local anesthesia could be an effective supplement for open decompression and fusion.

Comparison of 270-degree percutaneous transforaminal endoscopic decompression under local anesthesia and minimally invasive transforaminal lumbar interbody fusion in the treatment of geriatric lateral recess stenosis associated with degenerative lumbar spondylolisthesis.

PURPOSE: Various lumbar decompression techniques have been used for the treatment of degenerative lumbar spondylolisthesis (DLS). Few studies have compared the clinical efficacy of percutaneous transforaminal endoscopic decompression (PTED) and minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) in the treatment of lateral recess stenosis associated with DLS (LRS-DLS) in geriatric patients. The objective of the study was to compare the safety and short-term clinical efficacy of 270-degree PTED under local anesthesia and MIS-TLIF in the treatment of LRS-DLS in Chinese geriatric patients over 60 years old. MATERIALS AND METHODS: From January 2017 to August 2019, the data of 90 consecutive geriatric patients with single-level L4-5 LRS-DLS were retrospectively reviewed, including those in the PTED group (n = 44) and MIS-TLIF group (n = 46). The patients were followed up for at least 1 year. Patient demographics and perioperative outcomes were reviewed before and after surgery. The Oswestry Disability Index (ODI), visual analog scale (VAS) for leg pain, and modified MacNab criteria were used to evaluate the clinical outcomes. X-ray examinations were performed 1 year after surgery to assess the progression of spondylolisthesis in the PTED group and bone fusion in the MIS-TLIF group. RESULTS: The mean patient ages in the PTED and MIS-TLIF groups were 70.3 years and 68.6 years, respectively. Both the PTED and MIS-TLIF groups demonstrated significant improvements in the VAS score for leg pain and ODI score, and no significant differences were found between the groups at any time point (P > 0.05). Although the good-to-excellent rate of the modified MacNab criteria in the PTED group was similar to that in the MIS-TLIF group (90.9% vs. 91.3%, P > 0.05), PTED was advantageous in terms of the operative time, estimated blood loss, incision length, drainage time, drainage volume, length of hospital stay, and complications. CONCLUSIONS: Both PTED and MIS-TLIF led to favorable outcomes in geriatric patients with LRS-DLS. In addition, PTED caused less severe trauma and fewer complications. In terms of perioperative quality-of-life and clinical outcomes, PTED could supplement MIS-TLIF in geriatric patients with LRS-DLS.

Effects of atropine and tropicamide on ocular biological parameters in children: a prospective observational study.

BACKGROUND: The effectiveness of cycloplegia in delaying the progression of myopia and its application in refractive examination in children have been extensively studied, but there are still few studies on the effects of atropine/tropicamide on ocular biological parameters. Therefore, the purpose of this study was to explore the effects of atropine/tropicamide on children's ocular biological parameters in different age groups and the differences between them. METHODS: This was a prospective observational study in which all school children were examined for dioptres and ocular biological parameters in the outpatient clinic, and 1% atropine or tropicamide was used for treatment. After examination, we enrolled the patients grouped by age (age from 2 to 12 years treated by atropine, 55 cases; age from 2 to 10 years treated by tropicamide, 70 cases; age from 14 to 17 years treated by tropicamide, 70 cases). The ocular biological parameters of each patient before and after cycloplegia were measured, and the difference and its absolute value were calculated for statistical analysis using an independent-samples t test. RESULTS: We compared the value and the absolute value of the differences in ocular biological parameters before and after cycloplegia in the same age group, and we found that the differences were not statistically significant (P > 0.05). There were significant differences in the corresponding values of AL, K1 and ACD among the different age groups (P < 0.05). Before cycloplegia, there were significant differences in AL, K, K1, K2 and ACD in different age groups (P < 0.05). However, the differences in AL, K, K1, K2 and ACD among different age groups disappeared after cycloplegia (P > 0.05). CONCLUSIONS: This study demonstrated that atropine/tropicamide have different effects on cycloplegia in children of different ages. The effects of atropine/tropicamide on ocular biological parameters should be fully considered when evaluating the refractive state before refractive surgery or mydriasis optometry for children of different ages.

Changes in ocular biological parameters after cycloplegia based on dioptre, age and sex.

The effects of cycloplegia on ocular biological parameters in children have been extensively studied, but few studies have compared these parameters between different refractive states, ages, and sexes. Therefore, the purpose of this study was to investigate the changes in ocular biometry before and after cycloplegia in different groups based on dioptre, age and sex. We examined a total of 2049 participants in this cross-sectional study. A comprehensive eye examination was conducted before cycloplegia. Cycloplegia was implemented with the application of atropine or tropicamide. Ocular biological parameters were evaluated after cycloplegia, including axial length (AL), mean keratometry (K), flat keratometry (K1), steep keratometry (K2), central corneal thickness (CCT), anterior chamber depth (ACD) and white-to-white (WTW) distance. All the participants were categorized based on dioptre, age and sex. Statistical analysis was performed with paired t tests and Wilcoxon signed-rank tests. Regarding dioptre, AL was found to be increased significantly in the Fs, Ast and FA (p < 0.05) postcycloplegia groups. We observed significant increases in K, K1, K2 and ACD in the Fs group (p < 0.05) after cycloplegia. Regarding age, we found significant increases in AL, CCT and ACD in group 1 (p < 0.05), but AL decreased significantly in groups 2 and 3 (p < 0.05) postcycloplegia. There were no significant changes found in K, K1 and K2 in the three groups after cycloplegia (p > 0.05). Regarding sex, AL and WTW were found to decrease significantly among males and increase significantly among females (p < 0.05) postcycloplegia, while K, K1 and K2 showed the opposite trends. This study showed that there were differences in some ocular biological parameters after cycloplegia across different groups; in particular, there were significant differences in AL, CCT and ACD. Attention should be devoted to the influence of cycloplegia in clinical work.

Risk factors of new vertebral compression fracture after percutaneous vertebroplasty or percutaneous kyphoplasty.

Background: New vertebral compression fracture (VCF) may occur in patients who underwent percutaneous vertebroplasty (PVP) or percutaneous kyphoplasty (PKP) for osteoporotic vertebral compression fracture (OVCF). However, the risk factors of new VCF remain controversial. The research aimed to analyze the risk factors of new VCF after PVP or PKP. Methods: From August 2019 to March 2021, we retrospectively analyzed the patients who underwent PVP or PKP for OVCF at our institution. Age, gender, body mass index (BMI), smoking, drinking, hypertension, diabetes, fracture location, surgical method, Hounsfield unit (HU) value, preoperative degree of anterior vertebral compression (DAVC), bisphosphonates, bone cement volume, bone cement leakage, and cement distribution were collected. The risk factors were obtained by univariate and multivariate analysis of the data. Results: A total of 247 patients were included in the study. There were 23 patients (9.3%) with new VCF after PVP or PKP. Univariate analysis showed that age (p < 0.001), BMI (p = 0.002), fracture location (p = 0.030), and a low HU value (p < 0.001) were significantly associated with new VCF after PVP or PKP. A low HU value was an independent risk factor for new VCF after PVP or PKP obtained by multivariate regression analysis (OR = 0.963; 95% CI, 0.943-0.984, p = 0.001). Conclusions: In this study, a low HU value was an independent risk factor of new VCF after PVP or PKP.

An Analysis of the Risk Factors for Adding-on Phenomena After Posterior Hemivertebral Resection and Pedicle Screw Fixation for the Treatment of Congenital Scoliosis Caused by Hemivertebral Malformation.

Objective: To retrospectively analyze the risk factors for adding-on phenomena (AOP) after posterior hemivertebral resection (PHR) and pedicle screw fixation for the treatment of congenital scoliosis (CS) caused by hemivertebral (HV) malformation. Methods: Patients with CS who underwent surgery and were followed up for more than five years were included in this study. The d general data, such as gender, age, HV segment, Risser sign, and triangular cartilage, postoperative complications, and imaging data at different periods, including the standard anteroposterior and lateral x-rays of the total spine were collected. Results: In total, 58 patients were included in this study, of which 10 experienced AOP and 48 did not. The results of the single-factor analysis showed that there were statistically significant differences between the patients with AOP and those without in terms of the HV direction, lowest instrumented vertebra (LIV)-upper instrumented vertebra (UIV) (P < 0.05), and postoperative trunk shift (P < 0.05). The results of the logistic regression analysis showed that the HV direction and the postoperative trunk displacement distance were the main risk factors for postoperative AOP. The area under the receiver operating characteristic curve was 0.842 (P < 0.001). The best cut-off value of the adding-on index as an indicator of the occurrence of AOP after surgery was 0.67. When the adding-on index was >0.67, the incidence of postoperative AOP was 90.0%, and the non-occurrence rate was 22.9%. Conclusion: PHR and pedicle screw fixation is an effective way to treat HV malformation in CS. The HV direction, LIV-UIV, and postoperative TS are risk factors for AOP in patients with CS treated with PHR and pedicle screw fixation. The adding-on index has a high degree of accuracy for the prediction of the occurrence of AOP after PHR and pedicle screw fixation.

A comparative study of percutaneous endoscopic interlaminar discectomy and transforaminal discectomy for L5-S1 calcified lumbar disc herniation.

BACKGROUND: Percutaneous endoscopic lumbar discectomy (PELD) is a relatively safe and effective minimally invasive surgery in the treatment of calcified lumbar disc herniation (CLDH). However, studies on percutaneous endoscopic interlaminar discectomy (PEID) and percutaneous endoscopic transforaminal discectomy (PETD) for CLDH have rarely been reported. This research aimed to compare the clinical efficacy of PEID and PETD for L5-S1 CLDH. METHODS: We retrospectively analyzed 54 consecutive patients with L5-S1 CLDH treated with PELD at our institution from August 2016 to August 2020. Patients were divided into PEID group (n = 28) and PETD (n = 26) group according to the surgical methods. The demographic characteristics and surgical results of the two groups were compared. Clinical outcomes were estimated by the visual analog scale (VAS) for leg pain, Oswestry disability index (ODI) and modified MacNab criteria. RESULTS: All patients were successfully operated on by PEID or PETD. No significant differences in the demographic characteristics, intraoperative blood loss, postoperative hospital stay and complication rate were noted between the PEID and PETD groups. The excellent and good rates in the PEID group were similar to those in the PETD group (89.29% vs 88.46%, P = 1.000), whereas the PEID group exhibited superior results for operative time (min) (64.61 ± 5.60 vs 85.58 ± 8.52, P < 0.001) and fluoroscopy times (n) (2.93 ± 0.90 vs 13.35 ± 2.30, P < 0.001) compared with the PETD group. CONCLUSIONS: PEID has achieved good clinical efficacy as PETD for L5-S1 CLDH. Compared with PETD, PEID has the advantages of shorter operative time and a reduced number of fluoroscopy times in the treatment of CLDH.

Clinical comparison of percutaneous transforaminal endoscopic discectomy and unilateral biportal endoscopic discectomy for single-level lumbar disc herniation.

Purpose: To compare the clinical outcomes of percutaneous transforaminal endoscopic discectomy (PTED) and unilateral biportal endoscopic discectomy (UBE) for the treatment of single-level lumbar disc herniation (LDH). Materials and methods: From January 2020 to November 2021, 62 patients with single-level LDH were retrospectively reviewed. All patients underwent spinal surgeries at the Affiliated Hospital of Chengde Medical University and Beijing Tongren Hospital, Capital Medical University. Among them, 30 patients were treated with UBE, and 32 were treated with PTED. The patients were followed up for at least one year. Patient demographics and perioperative outcomes were reviewed before and after surgery. The Oswestry Disability Index (ODI), visual analog scale (VAS) for back pain and leg pain, and modified MacNab criteria were used to evaluate the clinical outcomes. x-ray examinations were performed one year after surgery to assess the stability of the lumbar spine. Results: The mean ages in the UBE and PTED groups were 46.7 years and 48.0 years, respectively. Compared to the UBE group, the PTED group had better VAS scores for back pain at 1 and 7 days after surgery (3.06 ± 0.80 vs. 4.03 ± 0.81, P < 0.05; 2.81 ± 0.60 vs. 3.70 ± 0.79, P < 0.05). The UBE and PTED groups demonstrated significant improvements in the VAS score for leg pain and ODI score, and no significant differences were found between the groups at any time after the first month (P > 0.05). Although the good-to-excellent rate of the modified MacNab criteria in the UBE group was similar to that in the PTED group (86.7% vs. 87.5%, P > 0.05), PTED was advantageous in terms of the operation time, estimated blood loss, incision length, and length of postoperative hospital stay. Conclusions: Both UBE and PTED have favorable outcomes in patients with single-level LDH. However, PTED is superior to UBE in terms of short-term postoperative back pain relief and perioperative quality of life.

Oblique lateral interbody fusion to treat lumbar spinal stenosis in a patient with situs inversus totalis: a case report.

Oblique lateral interbody fusion (OLIF) is a minimally invasive spinal surgery that is popular for lumbar degeneration and spinal deformity treatment because it causes minimal damage to the stability of the intervertebral structures. However, when encountering abnormal anatomical structures caused by situs inversus, surgical routes must be adjusted to avoid serious complications. A 42-year-old woman with lumbar spinal stenosis presented to our hospital. Preoperative X-ray and computed tomography indicated situs inversus totalis, with the abdominal aorta and inferior vena cava reversed. We established an appropriate surgical approach for OLIF via the right abdomen according to the characteristics of the anatomical structures. Postoperative X-rays showed adequate positioning of the interbody fusion cage and internal fixation screws. At the 3-month follow-up, the patient reported resolution of her symptoms. Vascular variations caused by situs inversus totalis can affect the course of OLIF. Understanding the unique anatomical structure in such patients is crucial for successful surgery and to avoid intraoperative complications.

Modular prosthesis fracture in a patient with developmental dysplasia of the hip: a case report and literature review.

BACKGROUND: Modular prosthesis fracture, especially distal femoral fracture, is a rare complication of total hip arthroplasty (THA). However, it is catastrophic, and may have a serious impact on the patients. A distal femoral prosthesis fracture in a patient with developmental dysplasia of the hip (DDH) with nonunion at the subtrochanteric osteotomy site has not yet been reported in any literature. This report presents the first such case, with a purpose of analyzing the causes of modular prosthesis fractures and nonunion of the osteotomy area, so as to provide orthopedic surgeons with experience and lessons. CASE PRESENTATION: We report the case of a 52-year-old woman with the distal femoral prosthesis fracture after THA and subtrochanteric osteotomy for Crowe type IV DDH. The patient had severe pain in the left thigh and her activities were limited. Plain radiographs revealed fracture of the left distal femoral prosthesis and nonunion in the subtrochanteric osteotomy region of the left femur. After a revision of the THA, the patient's symptoms were resolved. CONCLUSIONS: A prosthesis fracture combined with nonunion at the subtrochanteric osteotomy site is a rare complication. Modular THA combined with a subtrochanteric osteotomy in the treatment of Crowe type IV DDH should reduce the damage to blood supply and avoid further nonunion of the osteotomy area, which may otherwise lead to modular prosthesis fractures. A detailed preoperative plan and suitable rehabilitation program may help minimize the occurrence of subtrochanteric osteotomy nonunion and reduce complications, including femoral prosthesis fractures, in patients with DDH.

Experimental Study on Chloride Ion Diffusion in Concrete under Uniaxial and Biaxial Sustained Stress.

The existence of axial and lateral compressive stress affect the diffusion of chloride ions in concrete will lead to the performance degradation of concrete structure. This paper experimentally studied the chloride diffusivity properties of uniaxial and biaxial sustained compressive stress under one-dimensional chloride solution erosion. The influence of different sustained compressive stress states on chloride ion diffusivity is evaluated by testing chloride concentration in concrete. The experiment results show that the existence of sustained compressive stress does not always inhibit the diffusion of chloride ions in concrete, and the numerical value of sustained compressive stress level can affect the diffusion law of chloride ions in concrete. It is found that the chloride concentration decreases most when the lateral compressive stress level is close to 0.15 times the compressive strength of concrete. In addition, the sustained compressive stress has a significant effect on chloride ion diffusion of concrete with high water/cement ratio. Then, the chloride diffusion coefficient model under uniaxial and biaxial sustained compressive stress is established based on the apparent chloride diffusion coefficient. Finally, the results demonstrate that the chloride diffusion coefficient model is reasonable and feasible by comparing the experimental data in the opening literature with the calculated values from the developed model.

A comparison study of percutaneous endoscopic decompression and posterior decompressive laminectomy in the treatment of thoracic spinal stenosis.

BACKGROUND: Percutaneous endoscopic decompression (PED) is considered a minimally invasive and safe procedure in lumbar degenerative disease. Few authors report the success of PED for thoracic spinal stenosis (TSS) with thoracic myelopathy. The objective of this study was to compare the outcome of PED versus posterior decompressive laminectomy (PDL) for TSS. METHODS: We retrospectively reviewed 30 consecutive patients who underwent surgery for single-level TSS from January 1, 2015 to May 1, 2019.These patients were divided into PED (n = 16) and PDL(n = 14) group. Preoperative demographic characteristics and perioperative outcomes were reviewed. Pre- and postoperative neurological status was evaluated using the modified Japanese Orthopaedic Association (mJOA) score and the recovery rate (RR). RESULTS: The patients' mean age was 57.3 years (27-76) in PED group and 58.8 years (34-77) in PDL group. No statistical difference was found between two groups with regards to neurological status at pre-operative and final follow-up. The RR in PED group achieved the same improvement as PDL group (87.5% vs 85.7%, P > 0.05), while the PED brought advantages in operative time(m) (86.4 vs 132.1, p < 0.05), blood loss (mL) (18.21 vs 228.57, p < 0.05),drainage volume(mL) (15.5 vs 601.4, p < 0.05), and hospital stay (d) (3.6 vs 5.6, p < 0.05). CONCLUSIONS: Both PED and PDL showed favorable outcome in the treatment of TSS. Besides, PED had advantages in reducing traumatization. In terms of perioperative quality of life, PED could be an efficient supplement to traditional posterior decompressive laminectomy in patients with TSS.

Percutaneous Transforaminal Endoscopic Decompression for Geriatric Patients with Central Spinal Stenosis and Degenerative Lumbar Spondylolisthesis: A Novel Surgical Technique and Clinical Outcomes.

PURPOSE: Percutaneous transforaminal endoscopic decompression (PTED) is an ultra-minimally invasive surgical option for patients that does not involve the same amount of destabilizing facet joint removal as a traditional laminectomy. The objective of this study was to describe the procedure of PTED under local anesthesia for geriatric patients with central spinal stenosis and degenerative lumbar spondylolisthesis (CSS-DLS). MATERIALS AND METHODS: From January 2016 to December 2018, 30 consecutive geriatric patients who underwent surgery for single-level CSS-DLS were retrospectively reviewed. All patients were followed for at least 12 months (12-24 months). The visual analog scale (VAS) scores, Oswestry disability index (ODI) scores and modified MacNab criteria were used to evaluate the clinical results. RESULTS: The mean age was 73.1±6.0 years. Follow-up ranged from 12 to 36 months. The mean±SD values of the preoperative VAS for leg pain and ODI were 7.4±1.0 and 67.2±8.4, respectively. The values improved to 2.2±1.1 and 19.9±8.1 at 12 months postoperatively. The outcomes of the modified MacNab criteria showed that 93.3% of patients obtained a good-to-excellent rate. The percent slippage of spondylolisthesis before surgery (13.8±2.5%) and at the end of follow-up (14.0±2.5%) was not significantly different. CONCLUSION: PTED under local anesthesia could be a useful supplement to traditional decompression in geriatric patients with CSS-DLS.

Percutaneous Endoscopic Thoracic Decompression for Thoracic Spinal Stenosis Under Local Anesthesia.

BACKGROUND: Thoracic spinal stenosis (TSS), a common vertebral degenerative disease, is generally treated via surgical decompression. Percutaneous endoscopic thoracic decompression (PETD) under local anesthesia is considered a relatively safe, minimally invasive procedure. Few reports detail the success of endoscopic decompression for treatment of TSS caused by ossification of ligamentum flavum, the most common cause of TSS. This study investigated application of PETD for treatment of TSS caused by ossification of ligamentum flavum, ossification of posterior longitudinal ligament, or thoracic disc herniation. METHODS: From January 2017 to January 2019, 12 consecutive patients (6 men and 6 women) underwent PETD. TSS was caused by ossification of ligamentum flavum in 5 patients, thoracic disc herniation in 5 patients, and ossification of posterior longitudinal ligament in 2 patients. All cases were followed up for 1 year postoperatively. Preoperative and postoperative neurologic status was evaluated using the modified Japanese Orthopaedic Association score, and complications were documented. RESULTS: Average modified Japanese Orthopaedic Association score improved significantly from 6.25 ± 1.60 preoperatively to 9.75 ± 1.21 at final follow-up. Dural tear was observed in 1 case during the intervention, and 1 case had transient worsening of preoperative paralysis. Recovery at final follow-up was classified as excellent in 5 cases, good in 6 cases, and poor in 1 case. CONCLUSIONS: This retrospective analysis showed that PETD under local anesthesia may be a feasible alternative to treat TSS in elderly patients with other underlying complications for whom general anesthesia or major surgical trauma would be harmful.

Percutaneous transforaminal endoscopic decompression for lumbar spinal stenosis with degenerative spondylolisthesis in the elderly.

OBJECTIVES: Percutaneous transforaminal endoscopic decompression (PTED) under local anesthesia is rarely performed for lumbar spinal stenosis (LSS) with degenerative lumbar spondylolisthesis (DLS) because of the limited field of vision, inherent instability, etc. The objective of this study was to describe the procedure of the PTED technique and to demonstrate the early clinical outcomes. PATIENTS AND METHODS: From January 2017 to January 2019, 40 consecutive patients aged 60 and older were diagnosed with LSS with DLS in our institution and underwent PTED. All patient were followed up to 1 year postoperatively. The clinical outcomes were evaluated using the visual analogue scale (VAS), Oswestry Disability Index (ODI) and modified MacNab criteria. RESULTS: The mean age was 70.2 ± 7.1 years. Follow-up ranged from 12 to 24 months. The mean ± SD values of the preoperative VAS leg pain and ODI scores were 7.5 ± 1.1 and 67.3 ± 9.3, respectively. The scores improved to 2.2 ± 1.1 and 20.7 ± 8.1 at 12 months postoperatively. The outcomes of the modified MacNab criteria showed that 87.5 % of patients obtained a good-to-excellent rate. The percent slippage of spondylolisthesis before surgery (10.8 ± 2.6 %) and at the end of follow-up (11.0 ± 2.4 %) was not significantly different. One patient had a dural tear and intracranial hypertension, and one patient had tibialis anterior weakness. CONCLUSION: PTED under local anesthesia could be an effective treatment method for LSS with DLS in elderly patients. However, potential complications still require further evaluation.