BACKGROUND: Foreign studies have demonstrated that the blue light at 470 nm inhibits melatonin secretion and displays the most obvious biorhythm regulation. To date, light-emitting diode (LED) applied in regulating biorhythm remains poorly explored. OBJECTIVE: To explore whether a certain intensity of LED (blue) light could induce retinal injury in rats. DESIGN, TIME AND SETTING: Randomized, controlled animal experiment was performed at the Animal Laboratory of Peking University Third Hospital between May 2007 and April 2008. MATERIALS: A total of 32 SD rats and 16 BN rats were provided by Animal Department of Peking University Third Hospital. METHODS: A total of 16 SD and 16 BN rats were respectively randomly divided into test and control groups. Test group rats were placed in light boxes which were controlled by blue LED (wavelength 470 nm) at a intensity of 300-350μW/cm2, 4 hours everyday for 3 days. The remaining SD rats were placed in light box which was controlled by blue LED (wavelength 470 nm) at a intensity of 120-150μW/cm2, 4 hours everyday for 3 days. The control rats were not treated. MAIN OUTCOME MEASURES: At the second day after light irradiation, the rats of all groups were sacrificed and both eyeballs were harvested. The frozen sections were subjected to hematoxylin-eosin staining to observe changes of rat retina. RESULTS: A total of 48 rats were included in final analysis. The retina of SD rats became thinning and disorderly arranged following blue LED irradiation at density of 300-350μW/cm2, but the retina of BN rat remained unchanged similar to control group. After blue LED irradiation at density of 120-150μW/cm2, the retina of SD rat remained unchanged similar to control group. CONCLUSION: Blue LED light source irradiation at a intensity of 300-350μW/cm2 is safe to pigment-protected retina, and at a intensity of 120-150μW/cm2 does not injury retina of different races of rats.

Objective To investigate the protective effect of Ebselen on mitochondrial damage and its influence to Cytochrome C expression and the neuronal apoptosis after spinal cord injury in rats. Methods Sixty adult SD rats were ran-domly divided into 5 groups (12 each group). Spinal cord injury model was made using Allen's method. Sham operation group received only laminectomy;SCI group received laminectomy and spinal trauma;Saline group received saline injection intraperitoneally (0.1%DMSO) after injury;methylprednisolone group received 30 mg/kg methylprednisolone injection intra-peritoneally, ebselen group received 10 mg/kg ebselen injection intraperitoneally. The malonaldehyde (MDA) and glutathi-one (GSH)level at the injured sites of the spinal cord were detected 24 hours after trauma, and the expression level of Cyto-chrome C was also observed. Finally, neuronal apoptosis was identified by TUNEL staining. Results MDA level in the Eb-selen group was significantly lower than that in the SCI group, and GSH level was significantly elevated in the Ebselen group compared with SCI group (P<0.01). Expression of Cytochrome C in Ebselen group was lower than that in SCI group shown by Western blot, and the neuronal apoptosis in Ebselen group reduced significantly too compared with SCI group (P<0.01). Conclusion Ebselen can alleviate peroxidation,prohibit expression of Cytochrome C and inhibit neuronal apoptosis,thus it shows a protective effect to experimental acute SCI.

Objective To evaluate the clinical outcomes of sacral decompression and lumbopelvic fixation for neurologically impaired patients with sacral fracture-dislocation.Methods From January 2009 to December 2013,32 patients with sacral fracture and spino-pelvic dissociation of Roy-Camille types Ⅱand Ⅲ were treated at our department.They were 21 men and 11 women,with a mean age of 34.3 years.According to Roy-Camille classification,9 patients belonged to type Ⅱand 23 to type Ⅲ;25 patients had S1 fracture-dislocation and 7 S2 fracture-dislocation.After their overall conditions were stabilized,all were treated with open reduction,sacral decompression and lumbopelvic fixation.Pre-and post-operative neurological functions were recorded by Gibbons criteria.We analyzed the correlations between the neurological recovery and (i) the extent of cauda equina deficit and (ii) the continuity of sacral roots,as well as the correlations between the functional recovery of the bladder and bowels and the above two.The reduction and fusion status were evaluated by the Mears and Velyvis radiological criteria;clinical effectiveness was evaluated by Majeed scoring system.Intra-and post-operative complications were all recorded.Results The mean follow-up time for this series was 35 months (from 25 to 47 months).The average Gibbons score improved from 4.0 to 2.7 at the follow-ups.The patients with mild cauda equina deficit or with continuity of sacral roots achieved significantly better neurological recovery than those with severe cauda equina deficit or with discontinuity of sacral roots (P ＜ 0.001).However,the functional recovery of the bladder or bowels was not significantly correlated with the extent of cauda equina deficit or with the continuity of sacral roots.Anatomical reduction was achieved in 26 patients,satisfactory reduction in 5 and unsatisfactory reduction in one,yielding a satisfaction rate of 96.9％.Bony fusion was obtained in 29 patients at 3 months,but not until at 9 months in 2 patients,and still not at 9 months in one who showed no symptoms.The Majeed scoring showed 22 excellent,6 good and 4 moderate cases,giving an excellent to good rate of 87.5％.Two patients developed deep wound infection,3 complained of the pain related to hardware prominence,and one had unilateral rod breakage.Conclusions In treatment of sacral fracture with spino-pelvic dissociation,sacral decompression and lumbopelvic fixation can lead to effective neurological recovery,restoration of lumboscacral stability and alignment,early ambulation and prevention of deformity.Complete neurological recovery is more likely in patients with incomplete cauda equina deficit or with continuity of all sacral roots.

Objective To investigate outcomes of posterior instrumentation and fusion in treating ankylosing spondylitis (AS) combined with lower cervical fractures.Methods A retrospective case series study was made on 53 AS patients combined with cervical fractures or cervical thoracic fractures treated by posterior instrumentation and fusion from January 2006 to January 2013.There were 51 male and 2 female patients.The mean age of patients was 55 years old (range,34-69 years old).All the patients showed significant kyphosis on the thoracolumbar and cervicothoracic junction.A total of 20 patients had neurological dysfunction at different extents.According to the American spinal injury association (ASIA) classification,neurological status was scored as Grade A in 4 cases,Grade B in 5,Grade C in 4 and Grade D in 7.The operation time,total bleeding and decompression status were recorded during the surgery.Reduction,decompression condition and complications were evaluated.The neurological status and bone fusion were recorded at the follow-up.Results All surgeries were well accomplished.Mean surgical time was 3.7 h (range,2.9-5.3 h).Mean total bleeding was 690 ml (range,470-1 600 ml).Two patients died within 1 year follow-up because of internal diseases (1 case caused by respiratory system disease in 13 months postoperatively and 1 case caused by acute myocardial infarction in 15 months postoperatively).The mean follow-up time of other patients was 25 months (range,18-48 months).The CT scan manifested all patients achieved satisfactory fusion,and the mean time span of the fusion was 3.5 months (range,3-6 months) postoperatively.Among the 20 patients with various levels of neurological deficits before operation,the postoperative ASIA score was Grade A in 4 cases,Grade C in 2,Grade D in 4,and Grade E in 10.No instrumentation failure occurred during follow-up.Conclusion The posterior instrumentation and fusion for treating AS combined with cervical fractures can obtain satisfactory neurological results,spinal stabilization and clinical results,and hence an effective clinical problem-solving algorithm for such kind of patients.

Objective To evaluate the precise percutaneous sacroplasty (PSP) assisted by a Renaissance robot for sacral insufficiency fractures (SIF).Methods The clinical data of 12 SIF patients were retrospectively analyzed who had been treated from March 2016 to March 2018 at Department of Spinal Surgery,Honghui Hospital.They were 5 males and 7 females,aged from 55 to 76 years (average,67.5 years).They all received PSP assisted by a Renaissance robot.Their operation time,hospital stay and intraoperative radiation were recorded.The clinical efficacy was evaluated by comparing their visual analogue scale (VAS) and Oswestry disability index (ODI) before surgery,1 day,3 and 12 months after surgery.Results All the 12 patients underwent surgery successfully with no complications like cement leakage.Their operation time ranged from 32 to 47 minutes (mean,36.8 minutes),their hospital stay from 12 to 25 hours (mean 17.5 hours) and their intraoperative exposure to radiation from 0.87 to 1.53 mSv (mean,1.27 mSv).All the patients were followed up for 12 to 18 months (mean,15.8 months).Their VAS (1.7 ± 0.7) and ODI (22.8 ± 4.1) one day after surgery were significantly decreased than the preoperative values (7.6 ±0.9 and 43.7 ±4.6) (P ＜ 0.05).At 3 and 12 months after surgery,their VAS scores were 2.0 ± 0.8 and 2.4 ±0.8 and their ODI scores 21.5 ±4.3 and 23.0 ±4.6,respectively,showing no significant differences from the values at 1 day after surgery (P ＞ 0.05).Conclusion The PSP assisted by a Renaissance robot is safe and leads to satisfactory clinical efficacy for SIF as bone cement can be accurately injected into the target area of the fracture.

Objective:To evaluate the efficacy of unilateral puncture techniques in high-viscosity cement percutanueous vertebroplasty (PVP) in treatment of type I chronic symptomatic osteoporotic vertebral compression fracture (CSOVCF).Methods:A retrospective case control study was conducted to analyze the clinical data of 119 patients with type I CSOVCF admitted to Honghui Hospital affiliated to Xi'an Jiaotong University School of Medicine from December 2013 to December 2016. There were 42 males and 77 females, aged 58-95 years [(79.2±15.6)years]. All patients had bone mineral density of -4.5--2.5 SD [(-3.9±0.2)SD] (T score). The fractured segments included L 1-L 2 in 56 patients and L 3-L 5 in 63. All patients were treated by high-viscosity cement PVP with the unilateral puncture of transverse process and superior articular process in unilateral group ( n=60) and by the bilateral puncture approach with the Magerl method in bilaleral group ( n=59). The operation time, cement injection volume, and intraoperative fluoroscopy frequency were recorded. The visual analogue scale (VAS), Oswestry dysfunction index (ODI), anterior height ratio of injured vertebrae and Cobb angle were measured before operation, at postoperative 1 day and at the last follow-up. The adjacent vertebral fracture, cement leakage and other complications were recorded. Results:All patients were followed up for 12-48 months [(24.1±5.6)months]. The operation time in unilateral group [(21.5±6.5)minutes] was significantly shorter than that in bilateral group [(37.8±7.4)minutes] ( P<0.05). The cement injection volume in unilateral group [(4.2±0.7)ml] was less than that in bilateral group [(6.5±1.1)ml]( P<0.05). The intraoperative fluoroscopy frequency in unilateral group [(14.2±3.0)times] was less than that in bilateral group [(31.4±6.4)times] ( P<0.05). Both groups showed significant improvements in VAS, ODI, anterior height ratio of injured vertebrae and Cobb angle at postoperative 1 day and at the last follow-up compared with these before operation ( P<0.05), but there were no significant differences after operation between the two groups ( P>0.05). The incidence of adjacent vertebral fracture was 5%(3/60) in unilateral group and 8% (5/59) in bilaleral group ( P>0.05). Four patients (7%) had cement leakage in unilateral group and 11 patients (19%) in bilateral group ( P<0.05). No complications of wound infection, nerve injury or pulmonary embolism occurred. Conclusion:Compared with Magerl bilateral puncture approach, high-viscosity cement PVP with unilateral puncture of transverse process and superior articular process in treatment of type I CSOVCF has advantages of shorter operation time, less trauma, less radiation exposure and lower cement leakage rate.

Objective:To compare the clinical efficacies of robot-assisted and free-hand long segment screw fixation combined with wedge osteotomy in the treatment of type IV chronic symptomatic osteoporotic thoracolumbar fractures (CSOVCFs).Methods:A retrospective cohort study was conducted to analyze the clinical data of 72 patients with type IV CSOVCFs who were admitted to Honghui Hospital of Xi′an Jiaotong University from May 2019 to December 2021, including 22 males and 46 females; aged 61-82 years [(71.2±12.3)years]. Fracture segments were located at T 11-T 12 in 37 patients and at L 1-L 2 in 31. A total of 32 patients were treated with robot-assisted long segment screw fixation combined with wedge osteotomy (robot group) and 36 with free-hand long segment screw fixation combined with wedge osteotomy (free-hand group). The operation time, intraoperative bleeding volume, dosage of radiation exposure, intraoperative needle adjustment, time of single pedicle screw placement and accuracy of pedicle screw placement were compared between the two groups. The kyphotic Cobb angle, sagittal vertical axis (SVA), thoracic kyphosis (TK), lumbar kyphosis (LL), visual analogue scale (VAS) and Oswestry disability index (ODI) were measured preoperatively, at 3 days postoperatively and at the last follow-up. The incidences of facet joint violation, deviation in guide needle placement, cerebrospinal leak and proximal junctional kyphosis (PJK) were observed. Results:All patients were followed up for 12-26 months [(18.2±5.1)months]. The operation time and time of single pedicle screw placement showed no significant differences between the two groups (all P>0.05). The intraoperative bleeding volume was (502.5±58.3)ml in the robot group, less than that in the free-hand group [(690.2±45.9)ml]. The dosage of radiation exposure was (32.6±10.8)μSv in the robot group, lower than that in the free-hand group [(48.6±15.2)μSv]. The intraoperative needle adjustment was (2.1±0.3)times in the robot group, higher than that in the free-hand group [(20.7±5.8)times], and the accuracy of pedicle screw placement was 99.7% in the robot group, less than that in the free-hand group (91.8%) (all P<0.01). Compared with pre-operation, the kyphotic Cobb angle, SVA, TK and LL were significantly improved in both groups at postoperative 3 days and at the last follow-up (all P<0.05). Compared with postoperative 3 days, the kyphotic Cobb angle, SVA and TK were increased at the last follow-up within the two groups, but with no significant differences (all P>0.05). Compared with postoperative 3 days, the LL was decreased within the two groups at the last follow-up, but with no significant differences (all P>0.05). The VAS and ODI in the two groups were significantly lower at postoperative 3 days and at the last follow-up when compared with those before operation (all P<0.05), and both values were significantly lower at the last follow-up than those at postoperative 3 days (all P<0.05). There were no significant differences in the VAS or ODI at all time points between the two groups (all P>0.05). The incidence of facet joint violation in the robot group was 1.6%, markedly lower than that in the free-hand group (9.6%) ( P<0.01). The incidences of deviation in guide needle placement, cerebrospinal leak and PJK showed no differences between the two groups (all P>0.05). Conclusion:For type IV CSOVCFs, the robot-assisted long segment screw fixation combined with wedge osteotomy can better reduce intraoperative blood loss, decrease radiation exposure, improve accuracy of pedicle screw placement, and reduce facet joint violation when compared with free-hand long segment screw fixation combined with wedge osteotomy.

Objective:To compare the clinical efficacies of O-arm combined with CT three-dimensional navigation system assisted screw placement versus manual screw placement in treating lower cervical fracture and dislocation.Methods:A retrospective cohort study was used to analyze the clinical data of 41 patients with lower cervical fracture and dislocation, who were treated in Honghui Hospital, Xi′an Jiaotong University from May 2021 to February 2022. The patients included 26 males and 15 females, aged 31.5-48.6 years [(41.5±15.0)years]. The injured segments were C 3 in 3 patients, C 4 in 12, C 5 in 13, C 6 in 10 and C 7 in 3. Nineteen patients were treated with cervical pedicle screws by O-shaped arm combined with CT three-dimensional navigation system (navigation group, 76 screws) and 22 by bare hands (traditional group, 88 screws). The total operation time, effective operation time, single nail placement time, single screw correction times, screw distance from anterior cortex, intraoperative blood loss, intraoperative fluoroscopic radiation dose, incision length and length of hospital stay were compared between the two groups, and the height of intervertebral space, Cobb angle, interbody slip distance and American Spinal injury Association (ASIA) grade were compared before operation and at 3 days after operation. Visual analogue score (VAS), Japanese Orthopedic Association (JOA) score, and neck dysfunction index (NDI) were evaluated before operation, at 3 days, 3 months after operation and at the last follow-up. Accuracy of screw placement and incidence of complications (adjacent facet joint invasion, infection, screw loosening) were detected as well. Results:All the patients were followed up for 11.1-13.9 months [(12.5±1.4)months]. The total operation time, intraoperative blood loss, intraoperative fluoroscopic radiation dose and incision length in the navigation group were more or longer than those in the traditional group (all P<0.05). The effective operation time, single nail placement time, single nail correction times and screw distance from anterior cortex in the navigation group were markedly less or smaller than those in the traditional group (all P<0.05). There was no significant difference in the length of hospital stay between the two groups ( P>0.05). There were significant improvements in the height of intervertebral space, Cobb angle and interbody slip distance between the two groups at 3 days after operation (all P<0.05). There was no significant difference in the height of intervertebral space, Cobb angle, interbody slip distance or ASIA grade between the two groups before operation or at 3 days after operation (all P>0.05). Compared with pre-operation, the VAS, JOA score and NDI were significantly improved in both groups at 3 days, 3 months after operation and at the last follow-up (all P<0.05), with further improvement with time. There was no significant difference in VAS between the two groups before operation or at 3 months after operation (all P>0.05), but it was markedly lower in the navigation group compared with the traditional group at 3 days after operation and at the last follow-up (all P<0.05). There were no significant differences in JOA score or NDI between the two groups before operation or at 3 days and 3 months after operation (all P>0.05), but both were lower in the navigation group compared with the traditional group at the last follow-up (all P<0.05). The accuracies of placement of grade 0 and grade 0+1 screws were 92.0% (70/76) and 96.6% (73/76) in the navigation group, respectively, which were markedly higher than 88.7% (78/88) and 93.5% (82/88) in the traditional group (all P<0.05). The rates of adjacent facet joint invasion of A, B, and C degrees were 71.2% (54/76), 28.8% (22/76) and 0% (0/76) in the navigation group, respectively, while the invasion rates were 60.5% (53/88), 32.3% (28/88) and 7.3% (7/88) in the traditional group ( P<0.05). No screw loosening was noted in the navigation group, but the screw loosening rate was 9.1% (8/88) in the traditional group ( P<0.01). Conclusion:Compared with manual screw placement, O-arm combined with CT three-dimensional navigation system assisted screw placement for lower cervical fracture and dislocation has the advantages of shorter effective operation time, quicker screw placement, stronger screw holding force, better cervical stability, slighter postoperative pain, higher screw placement accuracy, and lower facet joint invasion and screw loosening rates.

Objective:To explore the efficacy of O-arm navigation system-assisted upper cervical pedicle screw internal fixation in the treatment of traumatic atlantoaxial instability.Methods:A retrospective cohort study was conducted to analyze the clinical data of 61 patients with atlantoaxial instability admitted to Affiliated Honghui Hospital of Xi′an Jiaotong University from January 2021 to June 2022, including 34 males and 27 females, aged 20-77 years [(50.2±13.1)years]. A total of 38 patients were treated with unarmed screw placement (unarmed group), and 23 with O-arm navigation system-assisted screw placement (navigation group). The unarmed group was divided into experienced group ( n=20) and unexperienced group ( n=18) based on the surgeons′ experience (whether they had 20 years or longer experience of spinal surgery and performed more than 100 atlantoaxial surgeries independently). The screw placement and surgical time of each group was recorded. The cervical CT scan was conducted at 7 days after surgery to evaluate the satisfaction rate of pedicle screw placement and cortical penetration rate according to Neo grading criteria. The cervical nerve function of the patients before, at 7 days after surgery and at the last follow-up was evaluated using the Japanese Orthopedic Association (JOA) score and the Neck Disability Index (NDI). The occurrence of complications was observed. Results:All patients were followed up for 9-25 months [(16.3±4.2)months]. There were no statistically significant differences in the screw placement and surgical time between the navigation group and the unarmed group (all P>0.05). The screw placement time of the navigation group was (41.0±7.8)minutes, longer than that of the experienced group [(23.6±6.8)minutes] ( P<0.01) and shorter than that of the unexperienced group [(50.1±10.1)minutes] ( P<0.05). The surgical time of the navigation group was (101.9±9.9)minutes, which was longer than that of the experienced group [(67.6±8.3)minutes] ( P<0.01) and shorter than that of the unexperienced group [(126.1±16.4)minutes] ( P<0.01). The satisfaction rate of pedicle screw placement and cortical penetration rate of the navigation group were 98.9% and 4.3%, respectively, which were better than those of the unarmed group (94.1% and 17.8%), the experienced group (96.2% and 13.8%), and the unexperienced group (91.7% and 22.2%) ( P<0.05 or 0.01). There was no statistically significant difference in JOA score or NDI before, at 7 days after surgery or at the last follow-up between the navigation group and the unarmed group, and no difference between the navigation group and the experienced group or the unexperienced group (all P>0.05). No complications such as spinal cord nervous or vascular injuries were observed during surgery in the navigation group or the unarmed group. Conclusions:Compared with the unarmed screw placement, O-arm navigation system-assisted upper cervical pedicle screw internal fixation shows no significant difference in screw placement time, surgical time, and postoperative neurological function status in the treatment of traumatic atlantoaxial instability, but has a higher accuracy in screw placement. Compared with the experienced surgeons′ unarmed screw placement, the technique also has higher screw placement accuracy but longer screw placement time and surgical time. Whereas in comparison with unexperienced surgeons′ unarmed screw placement, the technique can not only significantly improve its screw placement accuracy, while shortening screw placement time and surgical time so as to improve the surgical safety.

Objective: To compare the efficacy of unilateral and bilateral percutaneous kyphoplasty (PKP) for thoracolumbar osteoporotic vertebral compression fractures (OVCFs). Methods: A retrospective case control study was conducted to analyze the clinical data of 234 OVCFs patients admitted to Honghui Hospital affiliated to Xi'an Jiaotong University Medical College from June 2014 to January 2016. There were 95 males and 139 females, aged 60-89 years, with an average age of 68.3 years. The fractured segments included T₁₁ in 45 patients, T₁₂ in 65 patients, L₁ in 72 patients, and L₂ in 52 patients. A total of 116 patients were treated with PKP through unilateral puncture of transverse process and superior articular process (unilateral group), and 118 patients were treated with PKP through bilateral puncture of Magerl (bilateral group). The operation time, radiation exposure, bone cement injection and leakage were compared between the two groups. Visual analogue scale (VAS) and Oswestry dysfunction index (ODI) were used to evaluate the clinical efficacy and life quality improvement. The distribution of bone cement was observed by CT. The complications were recorded. Results: All patients were followed up for 25-36 months, with an average of 27 months. The operation time of unilateral group [(19.6±5.3)minutes] was significantly shorter than that of bilateral group [(35.6±8.9)minutes]; the radiation exposure [(0.65±0.22)mSv] was lower than that of bilateral group [(1.69±0.58)mSv]; the bone cement injection [(5.3±0.8)ml] was less than that of bilateral group [(6.5±1.3)ml] (P<0.05). The postoperative X-ray showed that 10 patients (8.6%) in the unilateral group and 22 patients (18.6%) in the bilateral group (P<0.05) were found with bone segment leakage, although without clinical symptoms. The postoperative VAS and ODI of the two groups were significantly improved than before operation (P<0.01), and there was no significant difference between the two groups (P>0.05). Bone cement was mainly distributed in the front and middle of the vertebral body (A2, B1, C2, D1) in the unilateral group and in the front 2/3 of the vertebral body (A, B, C, D) in the bilateral group. There were in total 10 patients with cerebrospinal fluid during intraoperative puncture, including two patients in the unilateral group and eight patients in the bilateral group (P>0.05). The puncture direction was adjusted during the operation, and there was no neurological damage after the operation. There were 16 patients with local pain caused by small joint injury, including two patients in unilateral group and 14 patients in bilateral group (P<0.05). The pain was relieved one month after physical treatment. A total of 30 patients had vertebral fracture again, including 18 in unilateral group and 12 in bilateral group (P>0.05), all of whom were treated with PKP again. Conclusion Compared with Magerl bilateral approach, PKP for OVCFs has the advantages of shorter operation time, less radiation exposure, low leakage rate of bone cement and good distribution of bone cement.