[Application of cortical bone trajectory screw and sacral alar screw internal fixation for surgical treatment of lumbar adjacent segment degeneration].

Objective: To explore the application of cortical bone trajectory screw (CBTS) and sacral alar screw (SAS) internal fixation in the treatment of lumbar adjacent segment degeneration (ASD) and evaluate its clinical effect. Methods: Data of 24 patients who were diagnosed with ASD and treated by CBTS or SAS in Beijing Chaoyang Hospital were retrospectively reviewed. There were 14 males and 10 females with a mean age of (67.9±8.2) years. The patients were followed-up for (2.6±0.4) years. Perioperative parameters including operation time, intraoperative blood loss and postoperative time on the ground were counted. All patients were followed-up for at least 2 years. Visual analogue scale (VAS) and the Oswestry disability index (ODI) were compared between pre-operation and at the last follow-up. The internal fixation-related complications, pseudarthrosis and adjacent re-degeneration were evaluated in the follow-up. Results: There were 14 proximal ASD patients, 8 distal ASD patients, 1 both ends ASD patient and 1 ASD patient in between the fusion surgeries. Bone mineral density (BMD) T score of the adjacent vertebrae was -1.98±0.91 on average. The ASD patients were re-operated with CBTS and SAS internal fixation technique. A small incision was made in the revision surgery and the original fixation was not completely cut open and removed. The mean operation time was (125±36) min, mean blood loss was (85±33) ml. The postoperative ambulation time was (3.1±1.9) days, and the hospitalization time was (9.0±2.6) days. Before the operation, the average VAS (back pain) score was 5.2±1.0, the average of VAS (leg pain) score was 6.8±1.9 and ODI was 56.6%±12.8%. VAS score was reduced to 1.4±0.6 (waist pain) and 0.9±0.4 (leg pain). ODI was improved to 13.8%±6.3%. All the difference between preoperative and the last follow-up was statically significant (all P<0.01). No internal fixation failure, pseudarthrosis and adjacent re-degeneration were observed in the final follow-up. Conclusion: The application of CBTS and SAS internal fixation techniques in the surgical treatment of lumbar ASD has the advantages of less trauma, faster postoperative recovery, reliable internal fixation, and fewer complications, especially in patients with low bone mineral density.

[Clinical application of sacral alar screw fixation in surgical treatment of lumbosacral degenerative disease].

Objective: To verify the safety and feasibility of sacral alar screw fixation and fusion surgery in lumbosacral area. Methods: The clinical and radiological data of patients receiving L5/S1 single-level cortical bone trajectory screw combined with sacral alar screw decompression fixation and fusion in Beijing Chaoyang Hospital due to lumbar spinal stenosis from January 2019 to January 2020 were retrospectively analyzed. The clinical data included operation duration, intraoperative blood loss, postoperative drainage, pain and function scores during follow-up. The radiological data included preoperative and postoperative follow-up X-rays and three-dimensional reconstruction of lumbar spine CT. The fusion status and complication of internal fixation, such as screw loosening and fixation failure were evaluated by the radiological examination. Results: According to the inclusion and exclusion criteria, a total of 16 patients (7 males and 9 females) were included, with an average age of (69.6±5.2) years. The patients were followed-up for (16.2±1.7) months. The average operation duration was (144±21) min, the intraoperative blood loss was (103±20) ml, and the postoperative drainage was (80±34) ml. The patient's low back pain visual analogue scale (VAS) score was 6.8±1.0 before surgery, and it was improved to 0.9±0.7 at the last follow-up; leg pain VAS score was 6.1±0.9 before the operation and it improved to 0.9±0.7 at the last follow-up; Oswestry disability index (ODI) function score was 66.2%±8.0% before the surgery and it decreased to 26.6%±7.2% at the last follow-up. No neurological complications, surgical site infection, screw loosening, internal fixation failure or cage displacement were observed during the follow-up. The fusion rate was 68.8% (11/16) at 6 months post operation. Conclusion: It is safe, feasible and effective to apply cortical screws combined with sacral alar screws in short-segment decompression, fixation and fusion surgery on the lumbosacral region to treat lumbosacral spinal stenosis.

[A long-term follow up study of cervical spondylotic myelopathy using diffusion tensor imaging].

Objective: To analyze the correlation between the parameters of diffusion tensor imaging (DTI) and the clinical function scores before and 5 years after anterior cervical discectomy and fusion (ACDF) by measuring the DTI signal of the maximum compression level (MCL) of the cervical spinal cord in patients with cervical spondylotic myelopathy (CSM). Methods: A prospective study was conducted and clinical data of 37 patients with CSM treated by ACDF in Beijing Chaoyang Hospital from February 2014 to February 2020 were analyzed. The MCL was studied with diffusion tensor imaging (DTI) of MRI. The changes of diffusion indexes (fractional anisotropy (FA)), and clinical function score including Modified Japanese Orthopedic Association (mJOA), neck disability index (NDI) and visual analog scale (VAS) of pain were compared among each follow-up point. The FA value and clinical function score were collected and the data was analyzed to determine whether the high signal intensity could be observed in T2-weighted imaging (T2WI) at each follow-up point. The changes of preoperative and postoperative data were compared, and the correlation between FA value and other two clinical function score were analyzed at each follow-up point. Results: There were 14 males and 23 females with a mean age of (55±10) years in this study. All patients received the surgery and the medullary symptoms improved significantly postoperatively. After 3 months, the mJOA and FA value were improved by 2.62±1.41 and 0.14±0.11 on average, respectively (both P<0.05); and there were significant differences in these two indexes between each follow-up point in two years after the operation (all P<0.05). At the MCL, there were strong correlations between the FA value and mJOA score pre-and postoperatively (rs=0.770, 0.729, both P<0.01). There was no significant correlation between mJOA, NDI and VAS (both P>0.05). Conclusions: The DTI sensitively reflects the improvement of spinal cord function and can be used as an important tool to predict and evaluate the state of spinal cord dysfunction in patients with CSM.

[Change of cervical sagittal alignment after the treatment of growing rods to the early-onset scoliosis].

Objective: To determine the impact of growing rods (GR) technique on cervical alignment in early-onset scoliosis (EOS) through the change of cervical alignment parameters after the GR surgery. Methods: Total of 24 consecutive EOS patients treated in Beijing Chao-Yang Hospital from 2009 to 2018 were retrospectively reviewed (17 males and 7 females). Cervical lordosis, T(1) slope and C(2-7) sagittal vertical axis (C(2-7)SVA), thoracic/lumbar Cobb angle, thoracic kyphosis (TK), global kyphosis Cobb angle, SVA were included in radiographic data in the full spinal standing X-ray before and post operation and at the last follow-up. Based on clinical data, including the upper instrumented vertebra (UIV), proximal junctional kyphosis (PJK) and the number of GR, patients were divided into different groups for statistical analysis. Logistic regression analysis was used to find the independent risk factors of the abnormality of C(2-7)SVA. Results: All patients received at least one time of distraction operation, the mean follow-up was (35±14) months. The C(2-7) Cobb angle increased from 17°±11° to 18°±9° and T(1) slope changed from 28°±13° to 28°±11° and C(2-7)SVA changed from (17±11) mm to (16±10) mm after the operation, but no significant differences were found in those indexes before and after the operation (t=-1.15, 0.14, 0.55, all P>0.05). At the last follow-up after GR technique, the C(2-7) Cobb angle, T(1) slope angle and C(2-7)SVA significantly increased when compared with those before the operation (t=-7.60, -4.08, -2.46, all P<0.05). The △C(2-7) Cobb angle and △T(1) slope angle PJK group was both more significant than those in non-PJK group (t=3.50, 3.25, both P<0.05); while there was no significant difference in the △C(2-7) Cobb angle and △T(1) slope angle when the choice of UIV and the number of GD were taken into account (t=-1.02, -1.61, -0.67, 0.31, all P>0.05). The occurrence of PJK was identified as an independent risk factor for the abnormality of C(2-7)SVA during the GR surgery with logistic regression analysis(OR=11.57, 95%CI: 1.49-91.54, P<0.05). Conclusions: When used for EOS to correct deformity, GR surgery will increase the cervical lordosis and T(1) slope angle of EOS patients. More attention should be paid to the cervical sagittal alignment and cervical sagittal imbalance in EOS patients with PJK.

[Effect of posterior lumbar fusion on the degeneration of adjacent segments using cortical bone trajectory screw fixation].

Objective: To compare the degenerative changes of adjacent segments after posterior lumbar fusion surgery using cortical bone trajectory (CBT) screws and pedicle screws (PS) in lumbar spinal degenerative disease. Methods: According to certain inclusion and exclusion criteria, prospective non-randomized study on cases of the single-segment lumbar spinal fusion surgery using cortical bone trajectory screws fixation and pedicle screws fixation in Beijing Chao-Yang Hospital from January 2015 to February 2016 was performed. The intervertebral space height (ISH), foramen height (FH), foramen width (FW), cephalad adjacent segment (CAS) and intervertebral disc degeneration grades at MRI scans were measured before surgery and during follow-up. Clinical symptoms were evaluated by Oswestry Dysfunction Index (ODI) score and pain visual analogue scale (VAS) before and during the follow-up. Radiologic adjacent segment degeneration (R-ASD) and symptomatic adjacent segment disease (S-ASD) patients were diagnosed during the follow-up. Paired sample t test was performed when data were compared before surgery and during follow-up. Results: A total of 69 patients were included in the study, 33 in the CBT group (male/female, 15/18), with an average age of (65±11) years, and 36 in the PS group (male/female, 17/19), with an average age of (64±10) years. The follow-up time was no less than 36 months. At the last follow-up, the ISH of the adjacent segments in the CBT group were not statistically different from that before surgery; the ISH of the adjacent segments in the PS group were significantly reduced compared with that before surgery (t=6.78, P<0.05). The loss of ISH, FH, and FW in the adjacent segments in the CBT group were smaller than those in the PS group, and the differences were statistically significant. During follow-up, 4 cases (12.1%) of R-ASD and no S-ASD were found in the CBT group, while 12 cases (33.3%) of R-ASD appeared in the PS group, which was significantly higher than that in the CBT group (χ(2)=4.35, P=0.04). According to MRI, the adjacent discs of PS group had significantly more severe degeneration at the last follow-up than the CBT group (Z=-2.14, P=0.03). Conclusions: Compared with the PS fixation fusion, the CBT screw fixation can effectively reduce the occurrence of adjacent segment degeneration.

[Assessment of biomechanical properties of paraspinal muscles in adolescent idiopathic scoliosis].

Objective: To assess the bio-mechanical properties of paraspinal muscles in adolescent idiopathic scoliosis (AIS). Methods: The MyotonPro® device and shear wave elasticity imaging(SWEI) technique were applied to detect the paraspinal muscle tone (F), stiffness (S), relaxation time (R), Deborah number (C) and elasticity (D) of paravertebral muscles on the concave side and convex side of scoliosis curvature at several points: apex of the curve (a), upper (b) and lower (c) limits of the curve in 23 cases of AIS treated from October to December 2017 in Beijing Chaoyang Hospital.Cobb angle of the main curve was measured on the standing anteroposterior whole spine radiograph.Pearson correlation analysis was applied to detect the relation between the bio-mechanical properties and Cobb angle of the main curve. Results: A total of 23 AIS patients [3 males and 20 females, mean age was (15±4) years] were assessed in this study.The mean Cobb angle was (66±33) degrees.The MyotonPro® data showed that the muscle tone on the concave side were all significantly greater than those on the convex side [a: (18.9±2.2) Hz vs (17.4±1.6) Hz, t=4.435, P<0.05; b: (18.2±2.0) Hz vs (16.7±1.7) Hz, t=4.183, P<0.05; c: (18.0±2.3) Hz vs (16.8±1.7) Hz, t=4.520, P<0.05]. The muscle stiffness on the concave side were all significantly greater than those on the convex side at the three points (t=1.974, 2.048, 1.749, all P<0.05). The relaxation time were all longer on the convex side (t=-3.422, -2.713, -2.380, all P<0.05). The Deborah number were greater on the convex side at a and b points (t=-2.939, -2.466, both P<0.05). No significant difference in elasticity was found between the muscles of the two sides.The SWEI results also indicated that the elasticity of the paraspinal muscles of the two sides were similar.The Pearson correlation analysis showed that stiffness on the concave side was moderate positively correlated with Cobb angle of the main curve (r=0.582, P<0.05). Deborah number on the two sides and relaxation time on the concave were moderate negatively correlated with Cobb angle of the main curve (r=-0.632, -0.432, -0.611, all P<0.05). Conclusions: The bio-mechanical properties of paraspinal muscles in AIS are different significantly between the concave and convex side and affected by the severity of scoliosis.

[Biomechanical effects on adjacent segments of different growing-rod fixation in early onset scoliosis].

Objective: To analyse the biomechanical effects on adjacent segments of different growing-rod (GR) fixation in early onset scoliosis through a finite element analysis method. Methods: A severe early-onset scoliosis patient was selected and the pre-operation and post-GR-operation (Upper instrumented levels: T(4), T(5). Lower instrumented levels: L(3), L(4)) whole spine 3-dimentional CT scan data were collected to build the finite models. Based on the different models, biomechanical differences on adjacent segments were analysed. Results: The stress on the adjacent structures decreased after the GR surgery compared with the pre-operation. Compared with the single GR, stress on T(3) vertebrae decreased by 6.2%, stress on T(3/4) disc decreased by 6.7%, stress on T(3/4) ligament decreased by 27.7%, stress on T(6) vertebrae decreased by 16.9%, stress on T(5/6) disc decreased by 1.2%, stress on T(5/6) ligament decreased by 40.4%, stress on L(2) vertebrae decreased by 32.6%, stress on L(2/3) disc decreased by 30%, stress on L(2/3) ligament decreased by 15.6%, stress on L(5) vertebrae decreased by 1.2%, stress on L(4/5) disc decreased by 15.7%, stress on L(4/5) ligament decreased by 100.0% in dual GR structure. The application of hook (s) on the upper instrumented vertebrae (s) decreased the stress on the cranial adjacent segment. Stress on T(3) vertebrae decreased by 2.8% and 2.2%, stress on T(3/4) disc decreased by 2.4% and 1.5%, stress on T(3/4) ligament decreased by 3.6% and 5.7% in single GR and dual GR models separately when the hook (s) were utilized. In the meanwhile, the stress on the adjacent segment was more concentrated in the single GR model. Conclusion: Dual-rod growing-rod and the application of hook (s) on the upper instrumented vertebrae could reduce the stress on the adjacent segments more effectively in patients with early onset scoliosis.

[Radiographic study of Coflex interspinous device for lumbar spinal stenosis].

OBJECTIVE: To assess the radiography change of lumbar spinal stenosis (LSS) treated with the implantation of Coflex interspinous device retrospectively. METHODS: Sixty patients (34 male and 26 female) with LSS who underwent the decompression and Coflex device implanted surgery from January 2010 to December 2013 were followed up. The mean age of the patients was 59.4 years. There were 33 cases underwent Coflex surgery and 27 cases underwent Topping-off surgery. The Coflex segment ranged from L1/2 to L4/5 (L1-2: 1, L2-3: 5, L3-4: 19, L4-5: 35). The foraminal height, foraminal width and intervertebral space height change of the Coflex segment as well as its adjacent segment were recorded pre-/post-operatively and at last follow-up.Meanwhile, the Oswestry Disability Index(ODI) and Visual Analog Scale(VAS) were measured in all patient pre-/post-operatively and at last follow-up. The measurement data was recorded asx±s. And the independent and paired samples t-test was used to conduct the statistical analysis. RESULTS: The foraminal height(FH) increased from (19.82±2.38) mm to (22.28±2.95) mm (P<0.05) post-operatively, and the FH decreased to (19.31±3.32) mm at the last follow up(P>0.05, compared to the post-operation). The average foraminal width(FW) was 11.2 mm, 11.58 mm and 11.12 mm at pre-/post-operation and follow up, which had no significant different change(P>0.05). The post-operative intervertebral space height (ISH) increased from (7.84±1.56) mm to (10.05±2.39) mm(P<0.05), and the ISH decreased to (7.91±1.77) mm at the last follow up(P>0.05, compared to the post-operation). The amount of the decreased FH and ISH had no significant difference when comparing the Coflex segment with its adjacent (Coflex±1) segments (P>0.05). The lumbar lordosis(LL) was 43.13°±15.93°, 38.41°±10.82° and 43.10°±13.21° at pre-/post-operation and follow up, there was no significant difference between pre- and post-operation(P>0.05). All patients showed statistically significant improvement(P<0.05) in the clinical outcome assessed in the VAS and ODI at the time of follow up compared to the pre-operation. The ODI score decreased from 65.12±13.56 to 9.89±1.77; the VAS score decreased from 8.02±1.81 to 1.66±0.51. CONCLUSIONS: Coflex device could temporarily improve the FH and ISH after operation. However, it could not maintain the improvement as the follow-up time extended. The surgical decompression is the responsible factor for the good clinical outcome but not the improvement of FH.

Single dose diclofenac suppository reduces post-Cesarean PCEA requirements.

PURPOSE: To assess the analgesic efficacy of administering, immediately after surgery, a single dose of diclofenac (100 mg suppository) to women who had undergone lower segment Cesarean section (LSCS) under combined spinal-epidural anesthesia, and received post-operative patient-controlled epidural analgesia (PCEA) with ropivacaine 0.2% and fentanyl 2 microg x ml(-1). METHODS: Forty-eight ASA physical status I or II term parturients scheduled for elective LSCS under regional anesthesia were enrolled into this randomised double-blind study. The patient-controlled epidural analgesia device was programmed to deliver a bolus of 4 ml of local anesthetic mixture with a lockout period of ten minutes and an hourly limit of 12 ml. There was no baseline infusion. The study commenced upon the patient's first demand for analgesia post-operatively and the patients were assessed at one, six, 12 and 24 hr post-operatively for pain scores on movement, dermatomal level of sensory blockade, degree of motor blockade and volume of local anesthetic used. At conclusion of the study, patients' satisfaction scores were recorded. RESULTS: The two groups of patients were similar demographically. Patients who received a diclofenac suppository used 52.8 +/- 17.8 ml of local anesthetic mixture while those who did not, used 74 +/- 25 ml (P <0.005). Pain scores and satisfaction scores did not differ significantly between the groups. CONCLUSION: A single administration of 100 mg diclofenac suppository is effective in reducing post-Cesarean epidural local anesthetic/opioid requirements by 33% for the first 24 hr post-operatively.