Background: Training beginners of the pedicle screw instrumentation technique in the operating room is limited because of issues related to patient safety and surgical efficiency. Three-dimensional (3D) printing enables training or simulation surgery on a real-size replica of deformed spine, which is difficult to perform in the usual cadaver or surrogate plastic models. The purpose of this study was to evaluate the educational effect of using a real-size 3D-printed spine model for training beginners of the free-hand pedicle screw instrumentation technique. We asked whether the use of a 3D spine model can improve (1) screw instrumentation accuracy and (2) length of procedure. Methods: Twenty life-size 3D-printed lumbar spine models were made from 10 volunteers (two models for each volunteer). Two novice surgeons who had no experience of free-hand pedicle screw instrumentation technique were instructed by an experienced surgeon, and each surgeon inserted 10 pedicle screws for each lumbar spine model. Computed tomography scans of the spine models were obtained to evaluate screw instrumentation accuracy. The length of time in completing the procedure was recorded. The results of the latter 10 spine models were compared with those of the former 10 models to evaluate learning effect. Results: A total of 37/200 screws (18.5%) perforated the pedicle cortex with a mean of 1.7 mm (range, 1.2–3.3 mm). However, the latter half of the models had significantly less violation than the former half (10/100 vs. 27/100, p < 0.001). The mean length of time to complete 10 pedicle screw instrumentations in a spine model was 42.8 ± 5.3 min for the former 10 spine models and 35.6 ± 2.9 min for the latter 10 spine models. The latter 10 spine models had significantly less time than the former 10 models (p < 0.001). Conclusion: A life-size 3D-printed spine model can be an excellent tool for training beginners of the free-hand pedicle screw instrumentation.

Background: Although literature provides evidence regarding the superiority of surgery over conservative treatment in patients with lumbar disc herniation, recurrent lumbar disc herniation (RLDH) was the indication for reoperation in 62% of the cases. The major problem with revisional lumbar discectomy (RLD) is that the epidural scar tissue is not clearly isolated from the boundaries of the dura matter and nerve roots; therefore, unintended durotomy and nerve root injury may occur. The biportal endoscopic (BE) technique is a newly emerging minimally invasive spine surgical modality. However, clinical evidence regarding BE-RLD remains limited. We aimed to compare the clinical outcomes after performing open microscopic (OM)-RLD and BE-RLD to evaluate the feasibility of BE-RLD. Methods: This retrospective study included 36 patients who were diagnosed with RLDH and underwent OM-RLD and BE-RLD. RLDH is defined as the presence of herniated disc material at the level previously operated upon in patients who have experienced a pain-free phase for more than 6 months. BE-RLD was performed as follows: two independent surgical ports were made inside the medial pedicular line of the target segment and on the intact upper and lower laminas. Peeling off the soft tissue from the vertebral lamina helps to easily identify the traversing nerve root and the recurrent disc material without dealing with the fibrotic scar tissue. Clinical outcomes were obtained using a visual analog scale (VAS) and the modified Macnab criteria before and at 2 days, 2 and 6 weeks, and 3, 6, and 12 months after surgery. Results: The data of 20 and 16 patients who underwent OM-RLD and BE-RLD, respectively, were evaluated. The demographic and perioperative data were comparable between the groups. During the year following the surgery, in the BE-RLD group, the VAS scores at each point were significantly improved over the baseline and remained improved up to 2 weeks after surgery (p < 0.05); however, no statistical difference between the two groups was observed after 6 weeks of surgery (p > 0.05). According to the modified Macnab criteria on the follow-up, the excellent or good satisfaction rates reported at 2 weeks, 6 weeks, 6 months, and 12 months after surgery were 81.25%, 81.25%, 75%, and 81.25%, respectively, in the BE-RLD group, and 50%, 75%, 75%, and 80%, respectively, in the OM-RLD group. Conclusion: BE-RLD yielded similar outcomes to OM-RLD, including pain improvement, functional improvement, and patient satisfaction, at 1 year after surgery. However, faster pain relief, earlier functional recovery, and better patient satisfaction were observed when applying BE-LRD. Trial registration: Retrospectively registered

Kang MS, et al. Clin Orthop Surg. 2022 Jul;14:e54. https://doi.org/10.4055/cios22050

Background: Many factors associated with chronic low back pain (CLBP) have been proposed, including individual, psychosocial, and physical factors. However, these associated factors are still controversial. Purpose: (1) To determine the prevalence of CLBP and (2) to analyze factors associated with CLBP in the general population using a nationally representative sample of South Koreans. Study design: Cross-sectional study. Patient sample: Data from versions IV-1, -2, and -3 of the Korea National Health and Nutrition Examination Survey (KNHANES), which were performed in 2007, 2008, and 2009, respectively (n = 24,871). Outcome measures: Multiple logistic regression analysis was performed to determine the association between several factors (age, gender, alcohol consumption, household income, education level, mid-intensity physical activity, depressive symptoms, vitamin D level, and comorbidities [stroke, ischemic heart disease, knee osteoarthritis, asthma, COPD, cancer history]) and CLBP. Methods: CLBP status was surveyed using a self-reported questionnaire. Demographic, socioeconomic status, comorbidities, and other factors were evaluated from health questionnaires, health and physical examinations, and laboratory tests. To analyze the association between these factors and CLBP, we used multiple logistic regression analysis. Results: Data from 17,038 participants were included in the final analysis, including 2,693 with CLBP and 14,345 without. The prevalence of CLBP was 15.8% in South Korean subjects, with a prevalence of 11.8% in men and 24.5% in women. After regression analysis, we found advanced age, female gender, mid-intensity physical activity, depressive symptoms, stroke, ischemic heart disease, knee arthritis, asthma, COPD, and cancer history were positively associated with CLBP. In contrast, alcohol consumption ≥ 1 drink per month, increased household income, higher education level, and vitamin D insufficiency were negatively associated with CLBP. Conclusions: Our study showed that CLBP was most common in the elderly and women in the general South Korean population. Several individual, socioeconomic, lifestyle, and health-related factors were associated with CLBP. These results demonstrate the influence of these factors on CLBP in the general population and suggest that consideration of these factors may improve the management of CLBP.

Objective: Biportal endoscopic transforaminal lumbar interbody fusion (BE-TLIF) is an emerging, minimally invasive technique performed under biportal endoscopic guidance. However, concerns regarding cage subsidence and sufficient fusion during BE-TLIF necessitate careful selection of an appropriate interbody cage to improve surgical outcomes. This study compared the fusion rate, subsidence, and other radiographic parameters according to the material and size of the cages used in BE-TLIF.Methods: In this retrospective cohort study, patients who underwent single-segment BE-TLIF between April 2019 and February 2023 were divided into 3 groups: group A, regular-sized three-dimensionally (3D)-printed titanium cages; group B, regular-sized polyetheretherketone cages; and group C, large-sized 3D-printed titanium cages. Radiographic parameters, including lumbar lordosis, segmental lordosis, anterior and posterior disc heights, disc angle, and foraminal height, were measured before and after surgery. The fusion rate and severity of cage subsidence were compared between the groups.Results: No significant differences were noted in the demographic data or radiographic parameters between the groups. The fusion rate on 1-year postoperative computed tomography was comparable between the groups. The cage subsidence rate was significantly lower in group C than in group A (41.9% vs. 16.7%, p=0.044). The severity of cage subsidence was significantly lower in group C (0.93±0.83) than in groups A (2.20±1.84, p=0.004) and B (1.79±1.47, p=0.048).Conclusion: Cage materials did not affect the 1-year postoperative outcomes of BE-TLIF; however, subsidence was markedly reduced in large cages. Larger cages may provide more stable postoperative segments.