[Clinical study of the Cobb+1 to Cobb fusion strategy for Lenke 5C adolescent idiopathic scoliosis patients with the lower lumbar apex].

Objective: To investigate the indications and surgical outcome of Cobb+1 to Cobb fusion strategy in Lenke 5C adolescent idiopathic scoliosis (AIS) patients with the lower lumbar apex. Methods: The clinical data of Lenke 5C AIS patients treated in Nanjing Drum Tower Hospital from August 2015 to December 2018 were retrospectively analyzed. The patients were followed-up for at least 2 years after surgery and treated with selective Cobb+1 to Cobb fusion strategy. The patients were divided into the normal lumbar apex group (apex location of the main curve was between T12 and L1) and the lower lumbar apex group (apex location of the main curve was below the disc of L1/L2). The occurrence of proximal decompensation in the two groups was compared. In addition, according to whether the patients had proximal decompensation at the last follow-up, the patients in the lower lumbar apex group were further divided into proximal decompensation group and non-decompensation group. The radiographic parameters and Scoliosis Research Society-22 (SRS-22) scores of the two groups were compared. Results: A total of 52 patients (19 cases in the normal lumbar apex group and 33 cases in the lower lumbar apex group), aged (15.3±1.6) years, were followed up for 2-5 (3.2±1.2) years. Six patients (6/19) in the normal lumbar apex group and 5 cases (15.2%) in the lower lumbar apex group showed proximal decompensation during follow-up, and the incidence was significantly higher in the normal lumbar apex group (P=0.034). Within the lower lumbar apex group, the patients with proximal decompensation (n=5) showed similar Risser grade, baseline thoracic Cobb angle, and main Cobb angle as those without proximal decompensation(n=28), and the differences were all not statistically significant (all P>0.05). However, the baseline thoracic/lumbar apical vertebra translation (AVT) ratio was significantly larger in patients with proximal decompensation (0.6±0.2 vs 0.4±0.2, P=0.042), but the postoperative upper instrumented vertebra (UIV) tilt angle was similar (4.5°±2.3° vs 6.2°±3.4°, P=0.312). Conclusion: Cobb+1 to Cobb fusion strategy, selecting UIV at 1 level above upper end vertebra (UEV), could be performed in Lenke 5C patients with the lower lumbar apex location. In addition, UIV could be selected at UEV+1 in patients with small baseline thoracic curve.

[Role of intercellular adhesion molecule-1 in adhesion and migration of mesenchymal stem cells in ankylosing spondylitis and its mechanisms].

Objective: To investigate the role and underlying mechanisms of intercellular adhesion molecule-1 (ICAM-1) in the adhesion and migration of mesenchymal stem cells (MSCs) in patients with ankylosing spondylitis (AS). Methods: Bone marrow and ligament tissues were collected during surgery from patients with AS and thoracolumbar fractures (as controls, HC) treated from October 2021 to October 2022 at Nanjing University Medical School Affiliated Nanjing Drum Tower Hospital. MSCs were isolated and cultured from the bone marrow using the Ficoll separation method. Cell morphology was observed under high-resolution microscopy, and differences in the cytoskeletal features between AS-and HC-MSCs were analyzed through immunofluorescence staining. The expression of ICAM-1 was quantified in both groups using real-time quantitative polymerase chain reaction (RT-qPCR) and flow cytometry. Transwell migration assays and wound healing experiments were conducted to evaluate the differences in migration rates between the two groups of MSCs. Results: The interspinous ligament and bone marrow was acquired in AS (2 males and 1 female; 33, 37, 32 years old, respectively) and no-AS patients (2 males and 1 female; 35, 32, 38 years old, respectively). AS-MSCs exhibited broader cell morphology compared to HC-MSCs under bright field and fluorescence microscopy. Immunofluorescence staining of the interspinous ligament showed higher expression of ICAM-1 (68.38±3.42 vs 48.31±2.43) and CD105 (37.97±2.16 vs 23.36±2.06) in AS patients (both P<0.001). Western blot and RT-qPCR analysis revealed significantly stronger protein expression and transcription levels of ICAM-1 in AS-MSCs when compared to those in HC-MSCs (both P<0.001). Flow cytometry confirmed greater mean fluorescence intensity of ICAM-1 in AS-MSCs than in that in HC-MSCs (924.30±54.99 vs 636.47±40.03, P=0.002). Regarding cell adhesion efficiency, it showed no significant difference between AS-MSCs and HC-MSCs in the early stage of adhesion (0.5 h: 1 496±213 vs 1 205±163, P=0.133), but they were all significantly higher in AS-MSCs in the later stage (1 h: 2 894±172 vs 1 908±155, P=0.002; 2 h: 4 540±286 vs 3 334±188, P=0.004; 3 h: 5 212±281 vs 4 208±303, P=0.014). Finally, cell migration experiments demonstrated a stronger migration capability of AS-MSCs compared to HC-MSCs (5 449±172 vs 4 016±155, P<0.001), and the inhibition efficiency of A-205804 on the migration rate of AS-MSCs was stronger than that on HC-MSCs (2 145±239 vs 3 539±316, P=0.004). Conclusions: The aberrant expression of ICAM-1 markedly influences the adhesion and migration dynamics of MSCs. Elevated ICAM-1 levels in MSCs derives from patients with AS significantly enhance their migratory capabilities.

[Impact of C2-femoral heads center and sacroiliac fixation on the occurrence of post-operative proximal junctional kyphosis in adults with spinal deformity].

Objective: To analyze the relationship between post-operative proximal junctional kyphosis (PJK) and C2-femoral heads center (C2-FH), pelvic fixation in adult spinal deformity (ASD) patients, so as to provide a reference for the preoperative decision-making and the postoperative intervention timely. Methods: It was a retrospective study that analyzed 34 cases of ASD patients who underwent posterior pedicle screw fixation in Nanjing Drum Tower Hospital between January 2017 and May 2017. ASD patients were divided into two groups according to fixation options: the sacroiliac fixation group and the non-sacroiliac fixation group. The spine-pelvis parameters were evaluated on full-length X ray films of spine at preoperatively, 2 weeks postoperatively and the last follow-up, and the incidence of PJK was recorded. Results: A total of 34 ASD patients (3 males and 31 females) were included in this study, with an average age of (58±6) years. The mean follow-up period was (2.9±1.0) years (2.0-4.0 years). The age, follow-up time and various spine-pelvis parameters showed no significant differences between the two groups (all P>0.05). The immediate postoperative C2-FH in the sacroiliac fixation group was significantly lower than that in the non-sacroiliac fixation group [(-69.46±30.85) mm vs (-31.62±15.31) mm, P<0.001]. The incidence of PJK was as high as 50.0% (8/16) in patients with sacroiliac fixation, but it was only 22% (4/18) in patients without sacroiliac fixation (P=0.016). At the last follow-up, the C2-FH of both groups were both higher than -20 mm (both were approximately -15 mm, P=0.976), indicating that the C2-FH was compensated in both groups. Due to the loss of the distal compensation ability, the incidence of PJK in the sacroiliac fixation group was higher than that in the non-sacroiliac fixation group. Due to the fixation of pelvis and most of lumbar spine, no significant differences were found in lumbar lordosis (LL), pelvic tilt (PT) and sacral slope (SS) at the last follow-up in both groups when compared with those after the operation (all P>0.05); while the thoracic kyphosis (TK) and cervical lordosis (CL) increased significantly (both P<0.05) to compensate C2-FH at the last follow-up. Conclusion: It's demonstrated that C2-FH< -2 cm and pelvic fixation are high risk factors of PJK in ASD patients. It is suggested that both global sagittal balance and pelvic fixation should be considered in decision-making and corrective surgery, rather than only focusing on spine-pelvic parameters.

[Occurrence of rod fracture and salvage methods after primary surgery of the congenital lumbosacral deformity associated with sacral agenesis].

Objective: To analyze the occurrence of rod fracture after surgery for lumbosacral deformity associated sacral agenesis and discuss the relevant salvage methods. Methods: The clinical records of 19 patients who underwent surgical treatment for lumbosacral deformity associated sacral agenesis from January 2001 to January 2018 were retrospectively reviewed, including 11 boys and 8 girls. The average age was (9.6±5.2) years. The outcomes of surgical correction and internal fixation were evaluated by postoperative regular follow-up. We also recorded the time and position of rod fracture occurrence. The Cobb angle, coronal balance and sagittal balance were measured and compared to analyze the corresponding salvage methods and revision outcomes. Results: Three patients encountered rod fracture during follow-up, so the incidence of rod fracture after surgery for lumbosacral deformity associated sacral agenesis was 15.8%(3/19). Based on their own conditions, we formulated the individualized strategy and performed the revision surgery through the posterior-only approach. The most critical step was abundant bone-grafting and fusion in the defected sacroiliac joint. After revision, the scoliotic Cobb angle improved in two patients (91.5° vs 47.5°, 49.0° vs 28.0°) and coronal balance improved in one patient (40.3 mm vs 24.3 mm). No complication reoccurred during follow-up. Conclusion: The rod fracture after surgery for lumbosacral deformity associated sacral agenesis is quite common, which is probably correlated with its unique deformed structure and biomechanical characteristics. The individualized salvage methods and adequate bone-grafting and fusion for the defected sacroiliac joint will guarantee the reconstruction and maintenance of spine balance after revision.

[Clinical study of selection of the upper instrumented vertebra at one level caudal to upper end vertebra in patients with Lenke 5C adolescent idiopathic scoliosis].

Objective: To investigate whether the upper instrumented vertebra (UIV) can be selected at one level caudal to upper end vertebra (UEV) in Lenke type 5C adolescent idiopathic scoliosis (AIS) patients. Methods: Total of 28 Lenke 5C AIS patients who underwent selective posterior fusion in Drum Tower Hospital of Nanjing University Medical School from September 2013 to September 2015 were included. There were 4 males and 24 females, with an age of (15.0±2.0) years, the Risser sign was graded 2-5. The following imaging parameters were measured on standing full spine X-ray before, immediately after the surgery and at the last follow-up: thoracolumbar/lumbar (TL/L) Cobb angle, coronal balance, UIV translation, lower instrumented vertebra (LIV) translation, UIV tilt, LIV tilt, and thoracic apical vertebral translation (T-AVT), lumbar apical vertebral translation (L-AVT). The patients were divided into two groups: decompensation group (n=6) and non-decompensation group (n=22). Radiographic parameters and Scoliosis Research Society (SRS)-22 scores were compared between the two groups. Results: Six cases (21.4%) had proximal decompensation at the last follow-up. There were no significant differences in Risser grade(3.8±1.0 vs 3.6±1.6), baseline thoracic Cobb angle(25.8°±2.2° vs 26.3°±6.4°) and TL/L Cobb angle(43.7°±3.4° vs 45.2°±6.5°) between the two groups (all P>0.05). However, the baseline lumbar/thoracic apical vertebra translation (L-T AVT ratio) was significantly higher in patients with proximal decompensation (6.3±1.3 vs 4.0±2.0, P=0.048). Conclusion: Selecting UIV at one level caudal to UEV, would not increase the incidence of proximal decompensation in Lenke 5C AIS patients with Risser higher than grade 2, the smaller baseline L-T AVT ratio, and with thoracic compensatory curve over 15°, and can obtain satisfactory clinical results.

[Similar coronal curvature may not represent the same 3-dimensional deformity in adolescent idiopathic scoliosis: a matched-pair study using EOS imaging system].

Objective: To analyze the preoperative axial plane and the surgical outcomes of the Lenke type 1A patients with adolescent idiopathic scoliosis (AIS) whose coronal curve type was matched but thoracic kyphosis (TK) was different. Methods: This study retrospectively reviewed a series of Lenke type 1A female AIS patients who underwent corrective surgery in the Department of Spine Surgery of Nanjing Drum Tower Hospital from May to August 2017. After matched with the Cobb angle of the main thoracic curve, the apical vertebral, the vertebra number included in the curve, the lumber modifier in the Lenke classification and Risser sign, 12 pairs of AIS patients, whose coronal curve was matched but thoracic kyphosis was different, were included in this study. The patients were divided into normal TK group and thoracic hypokyphosis group. EOS whole-body images were taken preoperatively and reconstructed by three-dimensional reconstruction. The whole spine anteroposterior X-ray was taken at 3 weeks after surgery. The radiographic parameters were measured on the preoperative and postoperative two-dimensional X-ray images: coronal Cobb angle, TK, lumbar lordosis (LL), pelvic incidence (PI) and pelvic tilt (PT). The vertebra rotation was obtained on the EOS three-dimensional reconstructed image, and the average vertebral rotation of the major thoracic curve (MTR), the average vertebral rotation of the proximal thoracic curve (PTR) and the average vertebral rotation of the lumbar curve (LR) were calculated. The paired sample t test was used to compare the difference of preoperative and postoperative radiographic parameters between the groups. Results: A total of 24 patients (12 pairs) were included in this study with an average age of (13.7±2.9) years. The preoperative Cobb angle was similar in the two groups (53.8°±10.2° vs 51.0°±11.1°, t=0.27, P=0.81). The average preoperative TK of the normal TK groups was 28.2°±6.1°, while that of the thoracic hypokyphosis group was 11.2°±5.6°(t=7.68, P<0.01). The MTR in the normal TK group was significantly smaller than that in the thoracic hypokyphosis group (10.2° vs 12.7°, t=-3.74, P<0.01), and there was a significant correlation between TK and MTR (r=0.30, P=0.03). As for the lumbar curve rotation, the LR of the normal TK group was significantly smaller than that in the thoracic hypokyphosis group (t=-2.65, P=0.002), but the absolute value of the two groups was similar (t=-0.33, P=0.31). The lumbar Cobb angle correction rate was significantly greater in patients with thoracic and lumbar curve rotating in the same direction than that in the opposite direction (81.1% vs 61.9%, t=4.24, P=0.005). Conclusions: It indicated that when the coronal deformity is matched, the MTR of the patients with thoracic hypokyphosis is significantly larger than that in the patients with normal thoracic kyphosis. The direction of the thoracic and lumbar curve rotation is required to be well concerned in the preoperative surgical planning.

Posterior second sacral alar iliac screw insertion: anatomic study in a Chinese population.

OBJECTIVE: To provide radiographic parameters for optimal placement of posterior second sacral alar iliac (S2AI) screw for instrumentation and fusion of scoliosis to the second sacral level in a Chinese population. METHODS: S2AI screw trajectories were mapped on three-dimensional computed tomography (3DCT) reconstructions of 60 normal adult pelvises. 1 mm inferior and 1 mm lateral to the S1 dorsal foramen were chosen as the entry point, and ideal S2AI screw trajectories were explored by rotating and cutting the 3D pelvis, ensuring that the trajectories were of maximum length and width. The directions and depth of these determined trajectories were then measured. RESULTS: The ideal S2AI screw trajectories could be found in each pelvis. The left and right screw trajectory parameters for males were shown as follows: angulation was L 29.15 ± 8.60° vs. R 29.96 ± 8.28° (p = 0.286) caudally in the sagittal plane and L 36.49 ± 3.14° vs. R 37.16 ± 3.14° (p = 0.165) laterally in the transverse plane. The maximal and intrasacral lengths of trajectory were L 121.25 ± 8.33 vs. R 120.63 ± 7.54 mm (p = 0.460) and L 26.20 ± 3.31 vs. R 26.92 ± 4.76 mm (p = 0.268). The entry point was L 28.87 ± 3.33 vs. R 29.79 ± 3.55 mm (p = 0.186) lateral to the second sacral midline, and L 44.14 ± 11.87 vs. R 43.89 ± 12.53 mm (p = 0.687) underneath the skin. The trajectories for females were more caudal (L: 34.50 ± 6.56° vs. 29.15 ± 8.60°, p = 0.009; R: 35.72 ± 7.53° vs. 29.96 ± 8.28°, p = 0.007) in the sagittal plane, but the lateral angulation in the transverse plane showed no difference between genders (p > 0.05). The female iliac medullar cavities were obviously narrower than those of males (L: 14.76 ± 2.46 vs. 16.98 ± 3.52, p = 0.006; R: 14.94 ± 2.60 vs. 17.00 ± 2.81, p = 0.005). Although the average maximal length of trajectories for females were about 5 mm shorter than those of males, intrasacral length were equal to those of males. Furthermore, both the distance from entry point to the S2 midline and skin in the transverse plane showed no difference between genders. CONCLUSION: The feasibility to insert S2AI screws to the sacrum and ilium in an Asian population along with the ideal entry angle and length of trajectory were identified for clinical practice.