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Aim: We conducted a novel classification system of degenerative lumbar spinal stenosis (DLSS) based on clinical manifestations and imaging (computed tomography and magnetic resonance imaging) features. We chose different minimally invasive surgical procedures according to our system. Clinical parameters and radiological findings will be assessed in the article., Material and Methods: A retrospective study was conducted on 96 patients undergoing minimally invasive surgery for DLSS. We chose different surgical procedures according to our novel classification system based on clinical manifestations, imaging features, and concurrence with other spinal diseases. Clinical parameters and radiological findings were assessed pre- and postoperatively., Results: The mean follow up period was 24 months (range, 15~36 months). There was a statistically significant improvement in the Visual Analogue Scale (VAS) score of low back pain and leg pain after surgery (p < 0.05). According to the Japanese Orthopaedic Association (JOA) scores, the operation efficacy was excellent in 57 cases, good in 36 cases, and fair in 3 cases. According to Bridwell's criterion, the fusion rate was 96% (48/50) in patients who underwent fusion surgery. There were no cages or pedicle screws related complications., Conclusion: Minimally invasive surgical treatment of DLSS has satisfactory outcomes according to the novel classification, but further long-term, prospective, randomized controlled studies involving a larger study group are needed to validate the long-term efficacy.

Study Design: A prospective study., Objective: To further investigate the implication of our surface locator and intradermal locator to reduce the radiation exposure to surgeons in minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) surgery., Summary of Background Data: Our previous studies published in the journal have introduced our novel spinal locators effectively minimizing fluoroscopic time during minimally invasive spinal surgery., Methods: Twenty patients underwent MIS-TLIF surgery with G-arm fluoroscopy from January 2013 to June 2013. There were 10 patients in group A who underwent standard MIS-TLIF using our spinal locators, and the other 10 in group B underwent conventional MIS-TLIF without spinal locators. The radiation dosages to the arm, the finger, the whole body, thyroid gland, gonad gland, and the eye of the surgeon were measured by thermoluminescence badges for both groups., Results: All 20 patients (9 male, 11 female), aged from 48 to 77 years old, successfully underwent the surgery. The operation time was 171.20±10.28 minutes for group A and 189.80±11.99 minutes for group B. The fluoroscopy time was 49.60±7.32 seconds for group A and 68.40±7.62 seconds for group B, hence a reduction of 27.49% was observed. There was no correlation between operation time and exposure time for group A or group B. The radiation reduction was 35.28% for the arm, 17.95% for the finger, 45.23% for the whole body, 53.62% for the thyroid gland (protected), 52.44% for the thyroid gland (unprotected), 44% for gonad gland (protected), 36.42% for the gonad gland (unprotected), 59.42% for the eye (protected), and 59.70% for the eye (unprotected)., Conclusion: The study indicated that radiation exposure to the surgeon would be effectively reduced in MIS-TLIF using our surface locator and intradermal locator, and it could be another practical choice for radiation-minimizing strategy.

Study Design: A magnetic resonance neurography (MRN)-based morphometric analysis of the working zone for posterolateral endoscopic lumbar discectomy (PELD) procedures on 32 health volunteers., Objective: The purpose is to utilize MRN as a noninvasive evaluation of the Kambin's working zone, and further to analyze operative safety of the PELD procedures., Summary of Background Data: Intraoperative nerve root injuries of PELD procedures occur relative to the Kambin's triangular working zone, which has been described previously based on formalin-fixed cadaver studies. However, the investigation in living individuals is not known. Thus, it is necessary to evaluate the dimensions of the working zone on both coronal and sagittal plane by radiologic assessments., Materials and Methods: MRN images of 32 health volunteers (average age 26.8 y; 18 men, 14 women) were analyzed from L1-L2 to L5-S1. On the coronal plane, we measured the distance from the superior endplate to the nerve root exiting from the dura (distance a), the distance from lateral aspect of the dura to the medial aspect of the nerve root along the superior endplate (distance b), and the angle between the nerve root and plane of the corresponding disk (angle α). On the transversal plane, the vertical distance from the upper facet surface to the exiting nerve root at the lower/upper disk margin level (distance c/d) was also measured., Results: On the coronal plane, distance a was 16.69±5.07 mm (range, 6.60-26.10 mm), distance b was 13.64±2.52 mm (range, 9.30-21.20 mm), angle α was 55.45±7.14 degrees (range, 40.00-73.00 degrees). Distance c on the transversal plane was 5.01±2.66 mm (range, 1.30-13.10 mm) and distance d was 1.99±1.26 mm (range, 0.70-7.80 mm). All these measurements increased as the spine level went down., Conclusions: The study indicated that MRN was a feasible noninvasive tool to evaluate the anatomic dimensions in the Kambin's working zone. Before PELD, radiologic measurements of this working zone were recommended to perform a safer procedure.

Objective: To assess a new intradermal locator device for percutaneous placement of lumbar pedicle screws., Material and Methods: Patients were alternately assigned to two groups. The locator group underwent lumbar pedicle screw placement using the intradermal locator. The control group was aided by traditional fluoroscopy. Baseline demographics, visual analog scale (VAS) pain scores, operation time, intraoperative fluoroscopy time and guidewire insertion time were recorded. All postoperative CT scans were reviewed by an independent spine surgeon to grade screw placement accuracy., Results: Thirty-six patients (180 screws) were assigned to the locator group and 30 patients (128 screws) to the control group. The locator device could significantly reduce the fluoroscopy time [3.9 sec (SD = 1.9) vs. 9.6 sec (SD = 5.8), p < 0.001] and guidewire insertion time [2.69 min (SD = 0.67) vs. 4.49 min (SD = 1.96), p < 0.001] compared with the conventional method for each pedicle screw. The whole operation time of the locator group was shorter than that of the control group [2-segment: 243.2 min (SD = 16.9) vs. 301.7 min (SD = 14.9), p < 0.001; 1-segment: 154.5 min (SD = 14.3) vs. 194.6 min (SD = 19.3), p < 0.001]. As for the rates of pedicle breaches, postoperative VAS scores, no significant difference was found between the two groups., Conclusion: The intradermal locator device could help reduce the radiation exposure in percutaneous pedicle screw placement while maintaining the accuracy.

Study Design: This is a prospective single-center nonrandomized control clinical study involving 220 patients who underwent the novel localization method or conventional methods preoperatively in a minimally invasive surgery in lumbar spine., Objective: To introduce a novel preoperative locator designed by the authors for a minimally invasive surgery in lumbar spine and to compare the novel localization method with conventional methods in mean localization time and the mean number of C-arm fluoroscopy use preoperatively., Summary of Background Data: Conventional localization methods for minimally invasive surgery in lumbar spine are associated with more fluoroscopy time and radiation exposure. We describe a novel preoperative locator to help localize spinal anatomic landmarks, minimize preoperative localization time, and decrease radiation exposure. There have been no prospective clinical reports published on the comparison of the novel localization method with conventional methods., Methods: A total of 220 patients, 86 (39.1%) men and 134 (60.9%) women with an average age of 53.8±16.4 years were prospectively evaluated. We divided all patients into 2 groups. Group A: the first 100 patients who received the conventional preoperative localization methods (the palpation method and the Kirschner wire method). Group B: the remaining 120 patients who localized the spinal levels with the help of the novel locator before surgery. The localization time and the number of C-arm fluoroscopy use preoperatively were recorded., Results: The mean localization time of patients in groups A and B were 7.37±3.77 and 3.85±2.45 minutes, respectively. The mean number of preoperative C-arm fluoroscopy use in groups A and B were 2.29 and 1.29. There was significant difference in mean localization time and the mean number of C-arm fluoroscopy use between groups A and B (P<0.05). There was no incidence of wrong-level surgery in both groups., Conclusions: The novel preoperative locator is a simple and practical device that can help to minimize preoperative localization time and decrease radiation exposure.